Comparative study between intact PTH and fragments of PTH in patients on hemodialysis and CAPD.

Twenty-nine patients on hemodialysis (HD) and 29 patients on continuous ambulatory peritoneal dialysis (CAPD) were studied. Serum calcium and phosphorous levels were similar in the 2 groups. Serum parathyroid hormone (PTH) levels were determined by 4 different methods. Mid-molecule PTH levels were higher in HD (1099.5 +/- 876.8 pmol/L) than in CAPD patients (541.0 +/- 138.8 pmol/L), p less than 0.001, while intact PTH levels were similar. The ratio MM-PTH/Intact PTH was higher in HD (55.2 +/- 29.0) than in CAPD patients (39.0 +/- 20.0), where p less than 0.01. In patients with similar C-PTH, those on CAPD had higher levels of intact PTH (46.0 +/- 27.0 pmol/L) than those in HD (29.3 +/- 29.0 pmol/L), p less than 0.01. The ratio C-PTH/intact PTH was higher in HD (104.9 +/- 39.6) than in CAPD patients (59.3 +/- 32.3), p less than 0.001. The Peritoneal Saturation Index (PSI) of MM-PTH was 23.4 +/- 12%, and it showed a hyperbolic correlation in respect to MM-PTH serum levels. We concluded that CAPD can modify the plasma C-PTH and MM-PTH serum levels by peritoneal losses of these fragments.     

Technical and clinical characterization of the Bio-PTH (1-84) immunochemiluminometric assay and comparison with a second-generation assay for parathyroid hormone

BACKGROUND: The Bio-Intact parathyroid hormone (1-84) assay (Bio-PTH), a newly developed two-site immunochemiluminometric assay, measures exclusively PTH (1-84) in contrast to second-generation "intact PTH" (I-PTH) assays. We investigated the technical performance and clinical significance of this new assay. METHODS: PTH was measured simultaneously by the Bio-PTH assay and Allegro intact PTH IRMA in sera from Japanese patients with calcium disorders. RESULTS: Measured Bio-PTH in serum was unaffected by six freeze-thaw cycles and was stable at 4 degrees C for 7 days and during storage at -20 or -80 degrees C over 28 days. The calibration curve was linear to 1800 ng/L. The detection limit was 3.9 ng/L. The intra- and interassay imprecision was <2.8% and 3.5%, respectively, for analyte concentrations spanning the range of the calibration curve. Bio-PTH was unaffected by a 1000-fold excess of PTH (7-84), although I-PTH reacted equally with PTH (7-84) and PTH (1-84). Bio-PTH was correlated with I-PTH in healthy individuals (r = 0.953; P <0.0001; n = 26) and in the full population without renal dysfunction (r = 0.994; P <0.0001; n = 62). In 72 volunteers, mean (SD) Bio-PTH was 22.2 (7.1) ng/L, or 62% of the mean I-PTH [36.1 (22.3) ng/L]. This ratio was 51% in hemodialysis patients (n = 177). Mean Bio-PTH was high in patients with primary hyperparathyroidism [121 (85) ng/L; n = 18] and hemodialysis patients [102 (104) ng/L; n = 177], low in idiopathic hypoparathyroidism [5.5 (2.8) ng/L; n = 4], and within 2 SD of the mean for healthy controls in Paget disease of the bone [34 (15) ng/L; n = 9] and bone metastasis [24 (12) ng/L; n = 8]. CONCLUSION: The Bio-PTH assay is sensitive and precise and produces expected results for patients with the studied disorders of calcium metabolism.     

Correlations among serum calcium, vitamin D and parathyroid hormone levels in the elderly in southern Taiwan

This study correlates serum vitamin D levels to related hormones and dietary intakes among 57 elderly Chinese above the age of 65 who were living in the same community in rural Southern Taiwan (Pingtung) and who had no conditions or drug intake known to interfere with the metabolism of vitamin D. Demographic characteristics, past medical history, medications, and dietary intake were collected via questionnaires. Venous blood samples were collected for analyses of serum 25-hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH) and calcium levels. Our results showed subjects in this study to have normal mean values of serum 25(OH)D, PTH and calcium levels. The mean serum 25(OH)D level was 36.21 (+/- 6.37) ng/ml, the mean serum PTH level 29.24 (+/- 18.62) pg/ml and the mean serum calcium level 9.14 (+/- 0.52) mg/dl. While the mean serum 25(OH)D and calcium values were not found to be significantly different between men and women, the mean serum PTH level was significantly higher in women (33.42 +/- 20.00 pg/ml) than in men (23.07 +/- 14.66 pg/ml) (p <.05), and serum PTH levels were significantly negatively correlated to serum calcium (r = -.33, p <.05) but not 25(OH)D (r = -.21). A higher intake of calcium was significantly associated with higher serum calcium levels (r =.29, p <.05), but not with serum 25(OH)D levels. Results from this study suggested that the elderly people living in Pingtung, a particularly sunny region, had normal serum 25(OH)D levels. The fact that the elderly women studied had higher serum PTH levels and that these levels were negatively correlated to serum calcium levels suggests that a higher PTH level in the elderly women may be related to susceptibility for osteoporosis. In an effort to provide optimal nursing care for the elderly by minimizing hip fractures and related morbidity, further nursing studies are needed to study the effects of the environment, dietary intake and bone metabolism.     

Mid-molecule parathyroid hormone assay comparison

Parathyroid hormone (PTH) assays are becoming available to clinical chemistry laboratories for in-house use. We evaluated the clinical utility of two mid-molecule PTH assays in comparison to a sensitive but technically demanding component assay. A normal reference population, and an abnormal population including cases of primary and secondary hyperparathyroidism, hypoparathyroidism, and humoral hypercalcemia of malignancy were tested. PTH determinations with each assay system and total serum calcium determinations were done on all specimens. The Endocrine Metabolic Center (EMC) kit assay and the Immuno Nuclear Corp. (INC) kit assay demonstrated adequate standard curve reproducibility and precision for clinical use. With the aid of calcium determinations each assay performed well in the separation of abnormal patient groups, and in the separation of abnormal from normal PTH-calcium homeostasis. PTH values for the reference population differed among the three assays. The component assay and the EMC assay had a negative correlation with serum calcium, but the INC assay had a positive correlation with serum calcium.     

Serum magnesium concentration is an independent predictor of parathyroid hormone levels in peritoneal dialysis patients.

BACKGROUND: Parathyroid hormone (PTH) is a cardinal factor in the pathogenesis of bone disease in the dialysis population. The spectrum of renal osteodystrophy has been reported to have changed during the past years, and adynamic bone disease has emerged as the most common bone disorder in these patients. Continuous ambulatory peritoneal dialysis (CAPD) is considered a risk factor for the development of this condition, and furthermore, the adynamic bone lesion is associated with a state of relative hypoparathyroidism (hypo-PTH). Calcium, vitamin D, and phosphorus play a key role in the control of parathyroid gland function in uremic patients. However, magnesium may also be able to modulate PTH secretion in a way similar to calcium. OBJECTIVE: The aims of this study were (1) to analyze the serum Mg concentration in a large group of CAPD patients, (2) to study the relationship between serum Mg and PTH levels, and (3) to investigate whether this relationship is independent of other factors, such as calcium, phosphorus, and calcitriol, that regulate parathyroid function. PATIENTS AND METHODS: We studied 51 stable patients, aged 23-77 years, under maintenance CAPD for more than 6 months (range 8-48 months). Calcium carbonate was used as a phosphate binder in all patients, and 9 subjects also received aluminum hydroxide. No patient had been previously treated with vitamin D. Biochemical parameters were prospectively evaluated over 6 months, and the mean values were computed. RESULTS: The mean serum Mg was 1.08 +/- 0.19 mmol/L, and hypermagnesemia, defined as a Mg level higher than 1.01 mmol/L, was found in 30 patients (59%). Thirty-one subjects (60%) had an intact PTH (iPTH) level lower than 120 pg/mL and were diagnosed as having relative hypo-PTH. Except for the values of iPTH and alkaline phosphatase, the only difference between the two groups was the serum Mg concentration, which was significantly higher in patients with hypo-PTH (1.16 +/- 0.15 mmol/L vs 0.91 +/- 0.14 mmol/L; p< 0.001). Furthermore, iPTH levels were lower in patients with hypermagnesemia than in subjects with normal serum Mg (69 +/- 49 pg/mL vs 190 +/- 89 pg/mL, p < 0.001). There was a significant correlation between serum Mg and PTH levels (r= -0.70, p< 0.01). After controlling for the effect of other variables by partial correlation analysis, a significant positive association between P and PTH (r= 0.25, p < 0.05), and a negative relationship between Mg and PTH (r= -0.57, p < 0.001) were evident. A forward stepwise multiple regression analysis showed that only P and Mg predicted PTH values (multiple r = 0.59, p < 0.001). CONCLUSIONS: Hypermagnesemia and hypoparathyroidism are frequent in CAPD patients. There is a significant inverse relationship between serum Mg concentration and iPTH levels. Furthermore, this association is independent of the most important factors regulating parathyroid gland function (calcium, phosphorus, and calcitriol). These results suggest that hypermagnesemia may have a suppressive effect on PTH synthesis and/or secretion. Therefore, elevated serum Mg levels may play a role in the pathogenesis of adynamic bone disease.     

Assessment of vitamin D and calcium status in healthy adult Austrians

BACKGROUND: Because there is reason to assume that also in Austria calcium and vitamin D malnutrition is wide-spread, we initiated a comprehensive study on calcium and vitamin D status in relation to bone health in a large group of the normal adult population. SUBJECTS AND METHODS: We assessed dietary calcium and vitamin D intake, serum concentrations of Ca2+, phosphate, alkaline phosphatase, 25(OH)D, 1,25(OH)2D, parathyroid hormone (PTH), follicle-stimulating hormone (FSH), sex hormones and bone mineral density (BMD) by double-energy X-ray absorptiometry at five different skeletal sites in 648 females and 400 males (age 21-76 years). RESULTS: Mean daily intake of vitamin D (101 IU, range 0.2-320) and calcium (569 mg, range 40-2170) was significantly less than the respective recommended dietary allowances. Two hundred and seventy-one (26%) individuals had hypovitaminosis D with serum 25(OH)D < 12 ng mL(-1), while serum Ca2+ was less than normal in 82 (7.8%) subjects. Multiple regression analysis revealed significant correlations between mean calcium intake and BMD in the femoral region in the men (r = 0.13, P < 0.05) though not in the women. No consistent data could be obtained for associations between BMD and vitamin D status, except for 25(OH)D and BMD at the spine in the men (r = 0.10, P < 0.05). 25(OH)D correlated negatively (P < 0.05) with age in the women (r = -0.11) and with PTH in the women (r = -0.11) and men (r = -0.16). Inversely, a significant (P < 0.001) age-related increase in PTH was observed in both sexes (men, r = 0.19; women, r = 0.14). CONCLUSIONS: Prevalence of hypovitaminosis D in adult Austrians is an imminent risk for development of secondary hyperparathyroidism with advancing age, and requires timely correction of nutritional deficits.     

Two-site assay of intact parathyroid hormone in primary hyperparathyroidism: studies in basal conditions, following adenoma removal and during calcium and EDTA infusion

This study has been carried out in order to investigate parathyroid hormone secretion in patients with primary hyperparathyroidism in basal conditions, during stimulation and suppression tests and following successful surgery. Parathyroid gland secretory activity has been evaluated by a highly sensitive immunoradiometric assay (IRMA) which detects only the biologically intact active hormone and with a well established midmolecule (MM) PTH RIA. There was a good correlation between the two assays in basal state (r = 0.779); however the correlation found between serum PTH levels and total calcium values was better for the intact hormone (P < 0.001) than for the radioimmunoassay (P < 0.05). Twenty-four hours following surgery, serum intact PTH levels were in all patients < 10 pg/ml while midmolecule PTH was still detectable, thereafter remaining at a higher level during the next six days. Serum IRMA PTH levels fell rapidly in response to the increase in serum calcium, then there was a trend to reach a plateau; serum midregion PTH levels fell, although slower than those of intact hormone. The percent increase obtained for serum intact hormone levels was higher than that observed for MM RIA, following EDTA stimulation. The results obtained indicate that the assays of intact and midmolecule parathyroid hormone clearly reflect different aspects of hormone metabolism ‘in vivo’ and may prove therefore to be useful for its investigation in various calcium disorders.     

碳酸钙口服片和碳酸钙咀嚼片对多次机采血小板男性献血者血清Ca2+和甲状旁腺激素水平的影响

目的 探讨碳酸钙口服片和咀嚼片对多次机采血小板男性献血者血清Ca2+和甲状旁腺激素(PTH)水平的影响.方法 采用简单随机抽样方法,选择2016年6月15日至7月15日,于深圳市血液中心捐献血小板的76例多次机采血小板男性献血者为研究对象.采用简单随机分组方法,将其分为3组:碳酸钙口服片组(n=27,机采前20 min口服碳酸钙D3片1片),碳酸钙咀嚼片组(n=25,机采前20 min口服碳酸钙D3咀嚼片1片)非未补钙组(n=24,机采前未服用任何补钙制剂).采用MCS+型血细胞分离机采集3组献血者血小板.并且分别于血小板机采前(机采前20 min),机采开始时,机采过程中(机采开始后约30 min),机采结束时,留取献血者静脉血5 mL.分别采用邻甲酚酞络合酮比色法和化学发光法,检测3组献血者的血清Ca2+和PTH水平.于血小板机采结束后,向碳酸钙口服片组和碳酸钙咀嚼片组献血者发放调查问卷,调查其对所服用碳酸钙制剂的满意度.采用统计学方法,比较3组献血者在血小板机采不同时间点的血清Ca2+和PTH水平,以及碳酸钙口服片组和碳酸钙咀嚼片组献血者对碳酸钙制剂的满意率.3组献血者一般资料比较,差异均无统计学意义(P＞0.05).结果 ①血小板机采前、机采开始时,3组献血者的血清Ca2+水平分别比较,差异均无统计学意义(P＞0.05).机采过程中,碳酸钙口服片组、碳酸钙咀嚼片组及未补钙组献血者的血清Ca2+水平分别为(2.26±0.06)mmol/L、(2.28±0.04) mmol/L和(2.24±0.06)mmol/L,3组比较,差异有统计学意义(F=3.47,P=0.04);碳酸钙口服片组与碳酸钙咀嚼片组,碳酸钙口服片组与未补钙组分别比较,差异均无统计学意义(P=0.08、0.36);碳酸钙咀嚼片组与未补钙组比较,差异有统计学意义(P=0.01).机采完成时,3组献血者的血清Ca2+水平分别为(2.25±0.06) mmol/L、(2.26±0.04) mmol/L和(2.17±0.05)mmol/L,3组比较,差异有统计学意义(F=21.29,P＜0.01);其中,碳酸钙口服片组和碳酸钙咀嚼片组比较,差异无统计学意义(P=0.56);但是均高于未补钙组,并且差异均有统计学意义(P＜0.01).②血小板机采前、机采开始时,3组献血者的血清PTH水平分别比较,差异均无统计学意义(P＞0.05).机采过程中,碳酸钙口服片组、碳酸钙咀嚼片组及未补钙组献血者的血清PTH水平分别为(110±21)pg/L、(102±26) pg/L和(161±40) pg/L;碳酸钙口服片组与碳酸钙咀嚼片组比较,差异无统计学意义(P=0.32);但是均低于未补钙组,并且差异均有统计学意义(P＜0.01).机采完成时,3组献血者血清PTH水平分别为(95±23)pg/L、(91±25)pg/L和(147±38)pg/L;碳酸钙口服片组与碳酸钙咀嚼片组比较,差异无统计学意义(P=0.09);但是均低于未补钙组,并且差异均有统计学意义(P＜0.01).③本研究共计发放调查问卷52份,均填写完整并收回.碳酸钙咀嚼片组献血者对碳酸钙制剂的满意率为92.0％(23/25),高于碳酸钙口服片组的59.3％(16/27),二者比较,差异有统计学意义(x2 =7.42,P＜0.01).结论 血小板机采前20 min口服碳酸钙咀嚼片,可使多次机采血小板男性献血者于机采过程中及机采结束后血清Ca2+和PTH水平保持稳定.碳酸钙咀嚼片口感良好,服用方便,可用于机采血小板献血者献血前使用.     

Evidence for alteration of the vitamin D-endocrine system in obese subjects.

Serum immunoreactive parathyroid hormone (PTH) is increased in obese as compared with nonobese subjects and declines with weight loss. To determine whether alteration of the vitamin D-endocrine system occurs in obesity and whether ensuing secondary hyperparathyroidism is associated with a reduction in urinary calcium, a study was performed in 12 obese white individuals, five men and seven women, and 14 nonobese white subjects, eight men and six women, ranging in age from 20 to 35 yr. Body weight averaged 106 +/- 6 kg in the obese and 68 +/- 2 kg in the nonobese subjects (P less than 0.01). Each of them were hospitalized on a metabolic ward and were given a constant daily diet containing 400 mg of calcium and 900 mg of phosphorus. Whereas mean serum calcium, serum ionized calcium, and serum phosphorus were the same in the two groups, mean serum immunoreactive PTH (518 +/- 48 vs. 243 +/- 33 pg/ml, P less than 0.001), mean serum 1,25-dihydroxyvitamin D [1,25(OH)2D] (37 +/- 2 vs. 29 +/- 2, P less than 0.01), and mean serum Gla protein (33 +/- 2 vs. 24 +/- 2 ng/ml, P less than 0.02) were significantly higher, and mean serum 25-hydroxyvitamin D (25-OHD) (8 +/- 1 vs. 20 +/- 2 ng/ml, P less than 0.001) was significantly lower in the obese than in the nonobese men and women. Mean urinary phosphorus was the same in the two groups, whereas mean urinary calcium (115 +/- 10 vs. 166 +/- 13 mg/d, P less than 0.01) was significantly lower, and mean urinary cyclic AMP (3.18 +/- 0.43 vs. 1.84 +/- 0.25 nM/dl GF, P less than 0.01) and creatinine clearance (216 +/- 13 vs. 173 +/- 6 liter/d, P less than 0.01) were significantly higher in the obese than in the nonobese individuals. There was a significant positive correlation between percentage of ideal body weight and urinary cyclic AMP (r = 0.524, P less than 0.01) and between percentage of ideal body weight and serum immunoreactive PTH (r = 0.717, P less than 0.01) in the two groups. The results provide evidence that alteration of the vitamin D-endocrine system in obese subjects is characterized by secondary hyperparathyroidism which is associated with enhanced renal tubular reabsorption of calcium and increased circulating 1,25(OH)2D. The reduction of serum 25-OHD in them is attributed to feedback inhibition of hepatic synthesis of the precursor by the increased serum 1,25(OH)2D.     

联机血液透析滤过纠正尿毒症血液透析患者钙磷代谢紊乱临床观察

目的 探讨联机血液透析滤过(HDF)、综合血液透析(HD)对患者钙、磷、甲状旁腺激素(PTH)清除效果.方法 取本血液净化中心维持性血液透析患者40例,随机分为两组,联机HDF组(n=20)和HD组(n=20).维持透析6个月后检测透析前、透析后钙、磷、PTH.结果 联机HDF组透析前后血钙水平为(1.90±0.35) mmol/L vs(2.20±0.67)mmol/L,HD组分别为(2.02±0.22)mmol/L vs (2.30±0.18) mmol/L,两组透析后血钙均有轻度升高,但两组透析后差异无统计学意义(P＞0.05);联机HDF组透析前后血磷水平为(2.45±0.41) mmol/L vs (1.70±0.15)mmol/L;而HD组分别为(2.52±0.60) mmol/L vs(1.82±0.20)mmol/L,两组患者接受透析后较透析前其血磷浓度均有明显的降低,并且两组透析后差异有统计学意义(P＜0.05).联机HDF组透析前后血PTH为(702.0±14.3)ng/L vs(345.0±16.8)ng/L; HD组分别为(697.2±13.2)ng/L vs(391.7±19.4)ng/L,两组患者在接受治疗后均有明显的降低,而联机组患者其治疗后含量明显低于HD组(P＜0.05).结论 联机HDF可以有效清除维持性血液透析患者血液中钙、磷PTH,改善患者预后.     

Immunoradiometric assay of parathyrin with polyclonal and monoclonal region-specific antibodies.

In this immunoradiometric assay (IRMA) of parathyrin (PTH) a polyclonal anti-amino-PTH(1-34) is the capture antibody and a radiolabeled monoclonal anti-hPTH(44-68) is the second antibody. Gel filtration of serum from a hyperparathyroid patient yielded only a single peak of PTH, corresponding to the elution position of synthetic PTH(1-84). Healthy elderly individuals (ages 78 +/- 5 y, mean +/- SD, n = 45) had PTH concentrations (21 +/- 13 ng/L) not significantly higher than those from healthy younger (38 +/- 11 y) adults (20 +/- 8 ng/L, n = 94). Assay results agreed well with those obtained with a carboxyl-terminal PTH assay both in normal subjects (r = 0.63, P less than 0.001) and in patients with primary hyperparathyroidism (r = 0.59, P less than 0.001). Both assays equally discriminated patients with surgically confirmed primary hyperparathyroidism from normal individuals, but the PTH(1-84) IRMA also allowed a nearly absolute discrimination between normal subjects and patients with primary hypoparathyroidism (undetectable serum PTH in 18 of 21 cases) and secondary hypoparathyroidism (caused by hypercalcemia that was caused by a malignant tumor, PTH 1.3 +/- 1.3 ng/L, n = 32). Moreover, the PTH(1-84) IRMA is more sensitive (detection limit in serum, 0.8 ng/L) and easier and quicker to perform than the carboxyl-terminal assay.     

良性原发性甲状旁腺功能亢进症患者血清1,25-二羟基维生素D3水平变化

目的探讨良性原发性甲状旁腺功能亢进症(primary hyperparathyproidism,PHPT)患者血清1,25-二羟基维生素D3[1,25-dihydroxyvitamin D3,1,25(OH)2D3]水平变化及与甲状旁腺激素(parathyroid hormone,PTH)、血钙、血磷的关系。方法良性PHPT患者56例为观察组,同期体检健康者1118例为对照组,采用电化学发光法检测2组血清1,25(OH)2D3、PTH水平,比色法测定血钙水平,磷钼酸盐法测定血磷水平。比较2组维生素D缺乏[1,25(OH)2D3<20μg/L]、严重缺乏[1,25(OH)2D3<10μg/L]的比率及不同年龄分层患者血清1,25(OH)2D3水平变化,Pearson法分析观察组维生素D缺乏、严重缺乏患者血清1,25(OH)2D3与PTH、血钙及血磷的相关性。结果观察组维生素D缺乏比率、严重缺乏比率(94.64%、46.43%)高于对照组(62.79%、14.13%)(P<0.05);Pearson相关分析显示,观察组血清1,25(OH)2D3与PTH、血钙及血磷均无线性相关性(r=-0.226,P=0.352;r=-0.274,P=0.256;r=0.073,P=0.593)。观察组年龄18~40岁、>40~60岁、>60岁患者血清1,25(OH)2D3[(10.76±3.17)、(10.61±5.01)、(10.72±4.85)μg/L]低于对照组[18~40岁:(18.19±9.86)μg/L,>40~60岁:(17.18±9.19)μg/L,>60岁:(17.91±10.52)μg/L](P<0.05);观察组维生素D缺乏患者血清PTH[(818.86±233.49)ng/L]、血钙[(2.98±0.59)mmol/L]、血磷[(0.78±0.17)mmol/L]与维生素D严重缺乏患者[(640.09±622.69)ng/L、(2.96±0.69)mmol/L、(0.75±0.20)mmol/L]比较差异无统计学意义(P>0.05);观察组维生素D缺乏、严重缺乏患者血清1,25(OH)2D3与PTH(r=-0.360,P=0.060;r=0.071,P=0.723)、血钙(r=-0.225,P=0.250;r=-0.228,P=0.252)、及血磷(r=0.239,P=0.221;r=-0.208,P=0.297)均无线性相关。结论良性PHPT患者血清1,25(OH)2D3低于正常人群,维生素D缺乏比率较高,且血清1,25(OH)2D3与PTH、血钙及.血磷无线性相关。     

Positive correlation of serum bio-intact PTH(1-84) but not intact PTH with parathyroid gland size in hemodialysis patients.

To evaluate the usefulness of newly-developed bio-intact parathyroid hormone (Bio-PTH) assay, which measures exclusively intact PTH(1-84) molecule, serum PTH level determined by Bio-PTH assay, in comparison with second-generation intact PTH (I-PTH) assay, was examined for its correlation with parathyroid gland size. Serum PTH was determined in 46 male HD patients, together with bone formation markers bone alkaline phosphatase, intact osteocalcin, N-terminal propeptide of type I collagen, and bone resorption markers deoxypyridinoline, pyridinoline, beta-crossLaps. Maximal diameter of parathyroid gland was determined with ultrasonography as the parathyroid gland size. Serum Ca and Pi correlated significantly with parathyroid gland size rationalizing our method to define parathyroid gland size. Serum Bio-PTH was correlated significantly in a positive manner with parathyroid gland size (R = 0.308, P = 0.0474), whereas serum I-PTH did not. Furthermore, parathyroid gland size did not exhibit a significant correlation with any of bone formation markers or bone resorption markers. The lack of correlation between bone markers and parathyroid gland size in HD patients may be explained by the occurrence of refractoriness of bone to PTH. In conclusion, serum Bio-PTH assay could provide a better assay than I-PTH assay to estimate parathyroid function in HD patients, due mainly to its exclusive correlation with parathyroid gland size.     

Determination of intact parathyrin by immunoradiometric assay evaluated in normal children and in patients with various disorders of calcium metabolism

We report the reference values for intact parathyrin (PTH) measured by a two-site immunoradiometric assay (IRMA) during childhood. The study has been carried out in 215 healthy children and adolescents, ages 2.0 to 18.7 years. Some patients with altered mineral homeostasis were also studied to assess the sensitivity of the method in a clinical setting. Mean intact PTH concentrations were 30.8 (SD 9.6) ng/L; the median was 28.5 ng/L. Normal reference values were 16.0-59.0 ng/L (95% confidence interval). The distribution of intact PTH values was nongaussian. We found no significant variations between males and females and no age-related variations. The IRMA used was sufficiently sensitive to detect differences in PTH concentrations between healthy children and patients with hypocalcemia or hypercalcemia.     

维持性血液透析患者全血微量元素与甲状旁腺激素水平的相关性分析

目的 探讨维持性血液透析(maintenance hemodialysis,MHD)患者血清甲状旁腺激素(parathyroid hormone,PTH)与全血微量元素之间的关系. 方法 采用单中心横断面研究,纳入2019年9月在暨南大学附属广州红十字会医院血液透析中心行MHD的患者.记录患者临床资料、用药情况,测定透...     

Intraoperative parathyroid hormone analysis: A study of 200 consecutive cases

BACKGROUND: Immunoassays for parathyroid hormone (PTH), with short incubation times and results available in <15 min, have allowed intraoperative monitoring of the success of parathyroid surgery. The purpose of this study was to evaluate the analytical performance of a rapid PTH assay and its clinical performance in a series of 200 patients. METHODS: PTH was measured with a modified immunochemiluminometric assay with a 7-min incubation time (QuiCk-IntraOperative(TM) Intact PTH assay). The rapid assay was compared with results in a central laboratory (immunoradiometric assay) in 44 EDTA-plasma specimens. The rapid assay was used intraoperatively in 200 consecutive cases with specimens analyzed before and 5-10 min after resection of the hypersecreting parathyroid gland(s). RESULTS: Intraassay imprecision was 12% at 28 ng/L and 11% at 278 ng/L. Regression analysis of results of the rapid PTH assay and the IRMA PTH assay in 44 parathyroidectomy patients yielded y = 1.26x - 12 ng/L, S:(y|x) = 26.3 ng/L, r = 0.984, and in 40 of 44 patients with values <200 ng/L, y = 1.02x + 1.9, S:(y|x) = 13.9, r = 0.947. In the 195 cases using intraoperative PTH testing with complete results and defined clinical outcomes, the overall accuracy of the assay in predicting surgical success was 88% using the criterion of a 50% decrease at 5-10 min and 97% including the subset of patients with delayed decreases of PTH. CONCLUSIONS: The rapid PTH assay had excellent analytical performance and excellent agreement with the PTH immunoradiometric assay and predicted the success of parathyroid surgery in this large series of consecutive patients.     

Effects of estrogen on mineral metabolism in postmenopausal women as evaluated by multiple assays measuring parathyrin bioactivity

Data on the effect of estrogen on immunoreactive parathyrin (iPTH) in postmenopausal women are conflicting. We administered estrogen or placebo to 21 postmenopausal women for 12 weeks and measured PTH bioactivity (bioPTH), using the renal cytochemical bioassay. Before treatment, there was a negative correlation between nephrogenous cAMP and the tubular maximum for urinary phosphate excretion and a positive correlation between values measured by a mid-region-specific PTH RIA and those measured in an immunoradiometric assay for intact PTH. Values measured by the midregion-specific RIA were also positively correlated with nephrogenous cAMP. BioPTH values were not correlated with other indices of PTH activity but were increased compared with values for younger subjects. After estrogen treatment there was no change in bioPTH activity despite an early decrease in serum osteocalcin and a later increase in nephrogenous cAMP. PTH concentrations measured by mid-region-specific or intact RIAs were unchanged, but sample size may have been insufficient to exclude the possibility of significant changes in these values. The effects of estrogen on mineral metabolism in postmenopausal women are time-dependent. Early effects are independent of PTH, and later effects are variably associated with increased PTH activity.     

中老年慢性肾病患者并发骨质疏松的相关因素分析

目的:分析慢性肾病并发骨质疏松的相关因素,为防治慢性肾病并发骨质疏松提供理论依据。方法:研究2016年7月至2017年7月我院收治的70例非透析慢性肾病患者的临床资料。采用双能X线骨密度仪测定患者骨密度值(BMD),并测定相关生化指标及骨代谢指标。根据慢性肾病患者的BMD,将其分为骨质疏松组(30例)和非骨质疏松组(40例)。比较两组患者的性别、年龄、病程、体重指数(BMI)、血钙、血磷、血清的骨碱性磷酸酶(BALP)、甲状旁腺激素(PTH)、维生素D、血肌酐、血清尿酸、肾小球滤过率(GFR)的差异并进行相关性分析。结果:根据WHO诊断标准,本研究中骨质疏松患者达42.86%,女性发病率为50.00%,而男性为32.14%。两组性别构成比无统计学差异(P>0.05)。两组比较,骨质疏松组年龄明显大于非骨质疏松组,病程显著长于非骨质疏松组,BMI低于非骨质疏松组,均具有统计学意义(P <0.05)。两组实验室指标比较,血钙、血磷、血肌酐、血清尿酸及GFR无显著差异(P>0.05);骨质疏松组BALP、PTH高于非骨质疏松组(P<0.05),而维生素D低于非骨质疏松组(P<0.05)。相关性分析显示, BMD与BMI、维生素D呈正相关(r=0.607,0.450,P<0.05);BMD与年龄、病程、BALP及PTH呈负相关(r=-0.581,-0.256,-0.383,-0.551,P<0.05);而BMD与与性别、血钙、血磷、血肌酐、血清尿酸及GFR无明显相关性(P>0.05)。结论:中老年慢性肾病患者具有较高的骨质疏松风险,女性骨质疏松发病率明显高于男性。年龄、病程、维生素D、BMI、 BALP及PTH是慢性肾病患者并发骨质疏松的相关因素,慢性肾病并发症与骨质疏松密切相关,临床中应引起重视。     

Clinical evaluation of two novel biointact PTH(1–84) assays in hemodialysis patients

Objectives

In chronic kidney disease–mineral and bone disorder (CKD-MBD), most treatment decisions are guided by parathyroid hormone (PTH) levels. Here, we aimed at assessing the technical and clinical performance of two novel automated biointact PTH(1–84) assays, from Roche Diagnostics (Ro) and DiaSorin (DS), in hemodialysis patients.

Design and methods

We recorded demographics, dialysis treatment characteristics, pharmacotherapy for CKD-MBD and laboratory work-up. Statistical methods included Passing–Bablok, and multiple linear regression.

Results

121 patients, dialyzing on average for 3.5 years (range: 0.1–22.5), with serum phosphate 1.9 ± 0.6 mmol/L (mean ± SD), participated in the study. Median serum concentration for intact PTH was 223 ng/L (range: 5–2844), and for biointact PTH(1–84) was 136 ng/L (Ro; range: 1–1644), respectively 138 ng/L (DS; range: 4-1580). Both biointact assays were significantly correlated (r = 0.98; Ro = 0.87 × DS + 19.60). Bland–Altmann plots revealed an average bias ± 2 SD of 10 ± 27 ng/L below 200 ng/L, and − 32 ± 157 ng/L above 200 ng/L (Ro minus DS). The variably adjusted association between PTH and serum phosphate was very similar, regardless of the PTH assay, but this was not the case for PTH-derived measures (ratios biointact/intact; differences intact minus biointact). (Log)PTH concentrations as well as serum phosphate were significantly associated with serum creatinine, but only in patients with > 0 mL urine per day.

Conclusions

Results from Roche and DiaSorin biointact PTH(1–84) assays were well correlated, but showed increased deviations at higher concentrations. Biointact PTH(1–84) levels are roughly two third of intact PTH. The association between PTH and serum creatinine may depend on residual renal clearance of PTH and/or serum phosphate.