Parathyroid Hormone Radioimmunoassay: The Clinical Evaluation of Assays Using Commercially Available Reagents

This paper reports on the diagnostic usefulness of two commercial PTH assay kits and four “in-house” assays using commercially available reagents, studying the same samples from normal controls and different patient groups. The ability of such assays to discriminate proven primary hyperparathyroid (1° HPT) patients from normals varied significantly but without any apparent correlation with assay components. For all assays, performance declined markedly in 1° HPT patient groups with lower serum calcium levels. Patients with PTH secondary to chronic renal disease were well discriminated from normal by all assays. Although immunoassays are useful in many cases of 1° HPT, it is difficult to develop C-terminal or mid-region PTH assays that are uniformly diagnostically useful in the clinical situation where they are of greatest potential use i.e. in cases of mildly hypercalcaemic 1° HPT.     

分化型甲状腺癌术后^（131）I清甲治疗对甲状旁腺功能的影响

目的：观察分化型甲状腺癌切除术后131I清甲治疗对甲状旁腺功能的影响。方法：：对174例（女116,男58）分化型甲状腺癌术后行131I清甲治疗的患者行血清甲状旁腺素（parathyroid hormone,PTH）检测,平均年龄（43.50±14.02）岁。血清PTH检测分四个阶段进行,分别为首次131I清甲治疗前（阶段Ⅰ）,首次131I清甲治疗后3个月（阶段Ⅱ）、6个月（阶段Ⅲ）和9个月（阶段Ⅳ）。174例患者均于阶段I检测后第2d行首次131I清甲治疗,61例患者于阶段Ⅳ检测后第2d行再次131I治疗。血清PTH测定均采用放射免疫分析,正常值为（5～20）ng/dl,PTH检测值低于5ng/dl认定为甲状旁腺功能减退,PTH检测值低于正常范围持续时间超过6个月,认定为持续性甲状旁腺功能减退,6个月内恢复正常,则认定为暂时性甲状旁腺功能减退。每个阶段中发现的甲状旁腺功能减退病例均以病例数（n）和发生率（%）表示,各阶段中PTH检测值均以x珋±s表示,各阶段间PTH值比较采用ANOVA分析,P〈0.05认为差异有统计学意义。结果：①阶段Ⅰ～Ⅳ中各发现68例（39.08%）,26例（14.94%）,16例（12.50%）和13例（15.12%）甲状旁腺功能减退。持续性甲状旁腺功能减退共发现2例,均产生于阶段Ⅰ。②阶段Ⅰ～Ⅳ所发现的甲状旁腺功能减退患者的PTH检测值分别为2.38±1.39,1.94±1.16,2.10±1.29和2.44±1.20ng/dl。经ANOVA分析,各阶段间PTH水平无明显统计学差异,F=0.863,P〉0.05。结论：分化型甲状腺癌切除术后131I清甲治疗会导致甲状旁腺功能减退,其发生可能与残余甲状腺内放射性131I对甲状旁腺产生的辐射损伤有关,其程度与手术所引起的无明显差异,其发生时间在131I清甲治疗后的较长时间内都有可能发生。所以,分化型甲状腺癌术后患者在131I清甲治疗后应定期复查血清PTH,以期及时发现甲状旁腺功能减退。     

Clinical studies on phosphate handling in hypercalcaemia

Phosphate indices (serum phosphate, tubular reabsorption of phosphate, renal threshold phosphate concentration (TmP/GFR) and index of phosphate excretion) were studied in 88 hypercalcaemic subjects: 64 with primary hyperparathyroidism (HPT) and 24 with hypercalcaemia from other causes, predominantly malignant disease. HPT patients as a group could easily be separated from normal subjects (n = 16) and patients with functional hypoparathyroidism (n = 7) by use of the phosphate variables but these indices were of little discriminating value for the differential diagnosis between HPT and hypercalcaemia from other causes. There was no difference in the urinary cyclic adenosine monophosphate (cAMP) excretion between the two hypercalcaemic patient groups, but HPT patients had clearly elevated serum parathyroid hormone (PTH) levels compared with normal PTH concentrations in patients with other causes of hypercalcaemia. A positive correlation between cAMP and serum calcium and an inverse relationship between cAMP and TmP/GFR were found in patients with hypercalcaemic malignant disease. These findings suggest the existence of a humoral factor with PTH-like effects in malignant disease. Since PTH levels were low, the physiological actions were apparently not mediated by circulating PTH. No difference in the values for phosphate variables, PTH, cAMP or serum calcium was found between renal stone-forming and stone-free patients with HPT.     

Parathyroid hormone (PTH) assay of parathyroid cysts examined by fine-needle aspiration biopsy

The authors report three cases of parathyroid cysts examined by the fine-needle aspiration biopsy technic. A presumptive diagnosis of parathyroid cyst was made when characteristic water-clear fluid was aspirated. The diagnosis was then confirmed by parathyroid hormone (PTH) assay. The authors believe that the C-terminal/midmolecule determination should be the assay of choice, because the N-terminal-specific assay gave normal or slightly elevated results in all the cases studied. If only an N-terminal-specific PTH assay is obtained, potential for a false negative diagnosis exists. With a correct PTH assay, a specific diagnosis of parathyroid cyst can be rendered, which enables appropriate treatment of total fluid aspiration, which thereby eliminates the need for thyroid hormone treatment or surgery in most cases. A discussion of PTH assays is presented along with speculations concerning the secretion of PTH by the parathyroid gland. The previous literature detailing cytologic findings and the PTH assays of parathyroid cysts diagnosed by the fine-needle aspiration biopsy are reviewed.     

Use of C-terminal parathyroid assays in a large metropolitan hospital

The use of C-terminal parathyroid (C-PTH) assays, performed at a commercial laboratory, was evaluated for one year at Charity Hospital, New Orleans. Of 72 patients, the most frequent diagnosis was primary hyperparathyroidism (1 degree HPT) (n = 17, 24 percent), followed by malignancy (n = 15, 21 percent), chronic renal disease (n = 10, 14 percent), and thiazide diuretics (n = 5, 7 percent). In the 1 degree HPT group, all were hypercalcemic (mean serum calcium, 11.6 ml per dL) and had elevated C-PTH. Patients with malignancy had higher mean serum calcium levels than patients with 1 degree HPT. Three patients with malignancy had elevated C-PTH; two had suspected coexisting 1 degree HPT and neoplasm; and one had suspected pseudohyperparathyroidism. Patients with chronic renal disease undergoing dialysis treatment had the highest C-PTH recorded (all had elevated C-PTH) but only 50 percent were hypocalcemic. Three of the five patients on thiazide diuretics had increased C-PTH, indicating that the withdrawal of this drug may unmask underlying hyperparathyroidism. Appropriate reasons for ordering C-PTH include evaluation of hypercalcemia (n = 32, 44 percent) or hypocalcemia (n = 12, 17 percent); indicated clinical reasons not included in the hyper- or hypocalcemic groups, including chronic renal disease in patients undergoing dialysis or transplant (n = 5, 7 percent); in suspected 1 degree HPT, (n = 5, 7 percent); and in patients with renal stones (n = 2, 3 percent) or on thiazide diuretics (n = 2, 3 percent). Based on laboratory and clinical criteria, C-PTH assay was appropriately used in 81 percent of the patients surveyed (58/72).     

Improvement in histological diagnosis of primary hyperparathyroidism with a monoclonal antiparathyroid antibody

The monoclonal antiparathyroid antibody E11 reacts with a glycoprotein of high molecular weight, which acts as a calcium receptor on the surface of parathyroid cells and mediates calcium regulation of parathyroid hormone (PTH) release. Reduced expression of the calcium receptor has been implicated as a cause of the defect in PTH regulation in the pathological parathyroid parenchyma of patients with hyperparathyroidism (HPT). The present study evaluated the efficacy of immunostainings with the E11 antibody in comparison with routine histopathological methods including staining by the oil red O technique for histological discrimination between normal and pathological parathyroid glands. Parathyroid tissue from euparathyroid individuals invariably presented intense and homogeneous surface staining, with the antibody on virtually all chief cells, while the pathological glands from patients with HPT consistently showed heterogeneous and reduced immunostaining. Even minimally enlarged pathological glands from individuals with mild hypercalcemia and the normal-sized glands associated with adenomas displayed parathyroid chief cells with reduced antibody reactivity. The monoclonal antiparathyroid antibody should constitute a useful tool in parathyroid histopathology not only by its ability to identify the parathyroid tissue, but also by directly demonstrating the functionally normal and abnormal cells within the parathyroid tissue.     

Aspects pratiques des dosages de PTH

New knowledge concerning PTH biology was accumulated during the past few years. The finding that the so-called “intact” PTH assays measure a “non 1-84” PTH fragment in addition to full-length PTH has led to the development of new assays. These new assays, which were initially thought to measure 1-84 PTH only, have been shown to recognize also another PTH species called “amino-PTH”. As the various names given to the different assay methods are highly confusing, there is a need for a simplified nomenclature. A simple way would be to identify the older “intact” PTH assays as second-generation assays and the new assays (Whole, CAP, BioIntact) as third-generation assays. Although of considerable potential interest for the comprehension of PTH physiology, the third-generation PTH assays have not yet proved to be superior to the second-generation assays in clinical practice. There is thus currently no recommendation to switch from the second-generation to the third-generation assays in clinical practice, or to use a ratio derived from the concomitant measurement of PTH with both assay-generation. Because second- and third-generation PTH assays are usually highly correlated, significant differences in the clinical information provided by these methods are unlikely. However, our opinion is that more definitive bone biopsy studies in dialyzed patients selected according to their bone- and calcium-related treatment are still needed to reach a consensus. Finally, we have proposed that PTH reference values should be established in healthy subjects with a normal vitamin D status. This supposes that 25OHD is measured in the reference population beforehand, and that the subjects with vitamin D insufficiency are eliminated from the reference group. Although more complicated than the usual way to establish normative data, we have shown that it decreases the upper limit of normal by 25–35%, enhancing thus the diagnostic sensitivity for hyperparathyroidism without a decrease in specificity.     

Recurrence in Parathyroid Hyperplasias Owing to Secondary Hyperparathyroidism is Predicted by Morphological Patterns and Proliferative Activity Values

The histological pattern and the cell proliferative activity (as detected by Ki-67 immunostaining) of a series of 50 parathyroid hyperplasias (PTHs) secondary to renal failure were studied to assess their value in predicting recurrence of hyperparathyroidism (HPT). On account of their clinical evolution, these cases were divided into two groups: recurrent HPT (23 cases) and nonrecurrent HPT (27 cases). A nodular growth pattern (as opposed to diffuse) was the prevalent one and was observed in 20 (74%) cases of nonrecurrent HPT and in 22 (95.6%) cases of recurrent HPT, a statistically significant difference (p<0.05). The Ki-67 proliferative fraction was 1.9% in recurrent HPT cases, as compared with 0.81% in nonrecurrent HPT, a difference which was statistically significant (p=0.001). We conclude that a nodular pattern of growth and an elevated Ki-67 proliferative fraction (>1.5%) in PTH are both associated with a higher risk of recurrence (4.30) of HPT.     

Parathyroid hormone: radioimmunoassay and clinical interpretation.

A radioimmunoassay for serum immunoreactive parathyroid hormone (iPTH), which has had widespread clinical use for five years, is described in detail. The iPTH results in large groups of patients are reported, and are discussed in relation to the specificity of the assay and in relation to other assays. The assay has excellent precision and is highly proficient in discrimination of groups of patients. Ninety-three percent of 412 patients with surgically proven primary hyperparathyroidism were confidently separated from normal subjects or patients with hypercalcemia owing to other causes, while 86 percent of 160 patients with chronic renal failure and secondary hyperparathyroidism had iPTH values more than 2 S.D. above the normal mean. Results in patients with ectopic hyperparathyroidism were lower than in primary hyperparathyroidism although these groups showed considerable overlap. The antiserum used in this assay for iPTH appears to be specific for the carboxy-terminal region of the secreted or intact form of PTH but recognizes predominantly the secreted form rather than carboxy-terminal fragments believed to be in the circulation. It does not recognize amino terminal fragments. The assay is useful in selective venous catheterization for preoperative localization of hyperfunctioning parathyroid tissue.     

LINE-1 hypomethylation in familial and sporadic cancer

Increased and decreased methylation at specific sequences (hypermethylation and hypomethylation, respectively) is characteristic of tumor DNA compared to normal DNA and promotes carcinogenesis in multiple ways including genomic instability. Long interspersed element (LINE), an abundant class of retrotransposons, provides a surrogate marker for global hypomethylation. We developed methylation-specific multiplex ligation-dependent probe amplification assays to study LINE-1 methylation in cases of colorectal, gastric, and endometrial cancer (N?=?276), stratified by patient category [sporadic; Lynch syndrome (LS); familial colorectal cancer type X (FCCX)] and microsatellite instability status. Within each patient group, LINE-1 showed lower methylation in tumor DNA relative to paired normal DNA and hypomethylation was statistically significant in most cases. Interestingly, normal colorectal mucosa samples from different patient groups displayed differences in LINE-1 methylation that mirrored differences between the respective tumor tissues, with a decreasing trend for LINE-1 methylation from patients with sporadic colorectal cancer to LS to FCCX. Despite the fact that the degree of LINE-1 methylation is generally tissue specific, normal colorectal mucosa, gastric mucosa, and endometrium from LS patients showed similar levels of LINE-1 methylation. Our results suggest that the degree of LINE-1 methylation may constitute a "field defect" that may predispose normal tissues for cancer development.     

Effects of secretin on parathyroid hormone and calcium in normal subjects, patients with hyperparathyroidism and patients with gastrinoma

In vitro studies have demonstrated that secretin can stimulate the release of parathyroid hormone (PTH), but reports concerning its effects on PTH and calcium in vivo are contradictory. To examine this question further, a bolus injection of secretin (75 IU) was given to 12 normal subjects and 10 patients with primary hyperparathyroidism (HPT). Six of the patients had multiple endocrine neoplasia and five had endocrine pancreatic tumours (EPT). Three normocalcaemic patients with EPT were also included in the study. The mean serum gastrin level rose significantly (from 19 to 40 pmol/l, p less than 0.01) within 15 min of secretin injection in the normal subjects. HPT patients without EPT had a somewhat higher mean basal level of gastrin (39 pmol/l, p less than 0.05 compared with controls), but it did not increase significantly after the secretin bolus. In six EPT patients the gastrin concentrations rose by more than 300 pmol/l. Although secretin had a biological capacity to release gastrin, it had no discernible effects on either serum PTH or serum calcium in any of the groups studied. Nor were any changes in PTH or calcium observed when secretin was given as a continuous infusion (3 IU/kg/h) over 90 min. Thus, our data do not support the concept that secretin, in vivo, is a secretagogue of PTH.     

Comparison of different parathyroid hormone radioimmunoassays in uremic patients with secondary hyperparathyroidism

Parathyroid hormone (PTH) levels of patients with chronic renal failure (CRF) were measured by three different radioimmunoassays (RIA); RIA for mid-region PTH by antibody CH9 (i-PTH) (1), RIA for intact fragments of PTH (intact PTH) and RIA for C-terminal fragments of PTH (PTH-C). PTH levels were higher in CRF patients undergoing hemodialysis therapy (hemodialysis patients) by all three methods. However, PTH levels measured only by i-PTH assay and intact PTH assay were significantly higher in patients with CRF who were not on dialysis (non-dialyzed CRF patients). PTH levels were above normal when creatinine clearance was below 45 ml/min in the intact PTH assay and 66 ml/min in the i-PTH assay. I-PTH levels were well correlated with the severity of osteitis fibrosa evaluated by the degree of periosteal resorption in the digits of hemodialysis patients. Since special handling of the sample is required for the intact PTH assay, i-PTH assay is the most suitable method for diagnosing secondary hyperparathyroidism in patients with CRF.     

Pathogenesis of anaemia in hyperparathyroidism

It is suggested that parathyroid hormone (PTH), when in excessive amounts, interferes with normal erythropoiesis by downregulating the erythropoietin receptors on erythroid progenitor cells in the bone marrow. Therefore, physiologic concentrations of EPO can no longer sustain normal red cell counts, so normocytic and normochromic anaemia ensues. In primary hyperparathyroidism (HPT), this effect is observed with very high concentrations of PTH. In secondary HPT during chronic renal failure, this effect is more pronounced because erythropoietin synthesis is impaired.     

Proliferative activity of the parathyroid cells in rats with secondary hyperparathyroidism

Proliferative kinetics of parathyroid cells in secondary hyperparathyroidism (HPT) are still unknown. We examined the histopathological changes and proliferative activity of parathyroid cells in spontaneously hypercholesterolemic (SHC) rats that exhibit secondary HPT and in normal Sprague Dawley (SD) rats from 3 weeks to 32 weeks of age. Proliferative activity [proliferating cell nuclear antigen(PCNA) labeling index], evaluated by means of immunohistochemical examination of PCNA, declined in SD rats with age from 10.8% at 3 weeks of age to 0.15% at 32 weeks of age. In SHC rats, a PCNA labeling index of 11.6% declined to 3.12% at 14 weeks of age and rebounded to 6.15% at 26 weeks of age. Parathyroid glands increased in size as determined by the maximum cross-sectional area, but in SHC rats, the increase was significantly greater, paralleling the progression of renal dysfunction, and at 32 weeks they were almost three times larger than in SD rats. Parathyroid hormone (PTH) levels in SHC rats also rose sharply after 20 weeks and reached 611 pg/ml at 32 weeks, while PTH in SD rats remained unchanged at approximately 110 pg/ml. This study showed that in the course of developing HPT in SHC rats, there is a large increase in the size of the parathyroid gland, a concomitant increase in PTH levels, and a PCNA labeling index that is higher than in normal SD rats.     

Use of hormonal parameters of phospho-calcium metabolism as a means of discriminating bone and joint disorders in patients with renal insufficiency

Serum carboxyterminal parathyroid hormone (PTH) concentration (homologous measurement of the 53-84 fragment and heterologous bovine measurement) has been measured and correlated with both clinical and radiological findings of secondary hyperparathyroidism (HPT), studied quantitatively according to a score published in literature, in 95 patients with chronic renal failure on maintenance hemodialysis. Mean serum PTH concentration (53.84) is statistically higher in patients with severe clinical and radiological evaluation of HPT than in patients with moderate or slight manifestations of HPT (M +/- DS: 515.8 +/- 243.7 pg/ml VS 271.3 +/- 166.1 pg/ml p less than 0.001). However, even with high serum concentration, serum PTH level does not allow to predict HPT severity, suggesting a retention of PTH fragments in serum without biologic activity probably.     

Detection of Phylogenetically Diverse Human Immunodeficiency Virus Type 1 Groups M and O from Plasma by Using Highly Sensitive and Specific Generic Primers

The high degree of genetic diversity within human immunodeficiency virus type 1 (HIV-1), which includes two major groups, M (major) and O (outlier), and various env subtypes within group M (subtypes A to J), has made designing assays that will detect all known HIV-1 strains difficult. We have developed a generic primer set based on the conserved immunodominant region of transmembrane protein gp41 that can reliably amplify as few as 10 copies/PCR of viral DNA from near-full-length clones representing group M subtypes A to H (subtypes I and J were not available). The assay is highly sensitive in detecting plasma viral RNA from HIV-1 strains of diverse geographic origins representing different subtypes of HIV-1 group M as well as HIV-1 group O. Of the 253 group M plasma specimens (subtypes A, 68 specimens; B, 71; C, 19; D, 27; E, 23; F, 33; and G, 12), 250 (98.8%) were amplified by using the gp41 M/O primer set. More importantly, all 32 (100%) group O plasma samples were also amplified with these primers. In vitro spiking experiments further revealed that the assay could reliably detect as few as 25 copies/ml of viral RNA and gave positive signals in HIV-1-seropositive specimens with plasma copy numbers below the limits of detection by all commercially available viral load assays. In addition, analysis of five seroconversion panels indicated that the assay is highly sensitive for early detection of plasma viremia during the "window period." Thus, the highly sensitive assay will be useful for early detection of HIV-1 in clinical specimens from all known HIV-1 infections, regardless of their genotypes and geographic origins.     

Parathyroid gland function in subgroups of metabolically mediated urolithiasis as evaluated by serum parathyroid hormone,and urinary and nephrogenous cyclic nucleotides

Summary In healthy controls (n=34) and in the various metabolically defined subgroups of urolithiasis patients, including primary hyperparathyroidism (pHPT), parathyroid hormone (PTH) was studied using two different antisera, as were the cyclic nucleotides (cAMP; cGMP) and related variables in both urine and plasma; in addition, the nephrogenous components of the cyclic nucleotides were also determined. In nonpHPT (so-called idiopathic) stone disease, nephrogenous cAMP (2-h fasting urine) was significantly lower than normal in the normo-calciuric majority (n=60), and also lower than normal (medians) in all the other subgroups (absorptive hypercalciuria,n=15; renal hypercalciuria,n=23; uric acid lithiasis,n=17; uric/calcium oxalate lithiasis,n=12). In contrast, it was significantly elevated in pHPT (n=20), and only in this latter condition was nephrogenous cGMP (2-h urine) elevated. The total nucleotide production (sum of nephrogenous cAMP + nephrogenous cGMP) is again significantly lower only in normo-calciuric calcium stone disease. Except for high values in pHPT, no differences in plasma nucleotides are observed. Stone patients (idiopathic and pHPT) have significantly lower-than-normal serum phosphate and phosphate threshold in common. With the exception of pHPT, the differences in serum calcium are only minute, while ionised calcium is moderately elevated within the normal range in the serum of renal hypercalciuria patients.In all subgroups of idiopathic lithiasis, PTH is either normal to low (intact hormone assay), or slightly but significantly elevated in three subgroups (absorptive and renal hypercalciuria, patients alternately forming uric acid or calcium oxalate stones), when measured in an assay recognizing only a bioinactive hormone fragment (mid-portion assay). In surgically proven pHPT, median PTH established with the same two assays, is elevated by a factor of 8 (intact hormone assay), or 3 (mid-portion assay) in comparison with healthy controls.From the results it is concluded that a) idiopathic urolithiasis is accompanied by normal or low renal bioactivity of the parathyroid glands in the presence of a low renal phosphate threshold concentration; b) the elevated serum PTH in three idiopathic subgroups measured with an antibody with recognition largely of the bioinactive mid-portion of the hormone, is not in accordance with the simultaneously normal or low urinary and nephrogenous cAMP of these individuals, but is in accord with the normal or low serum PTH measured with an antibody recognizing all regions of the human hormone; c) the activity of tubular guanylate cyclase in pHPT is probably increased, but not in situations where both hypercalcemia and a considerable excess of parathyroid hormone are absent (remaining groups).     

Mesure de la parathormone : facteurs de variation et problèmes de standardisation

The parathyroid hormone (PTH) assay still involves some problems, considering the molecular heterogeneity and the different specificity of the available sandwich immunometric methods. A number of preanalytical variation factors can affect the PTH measurement: the intraindividual biological variability (pulsatile secretion, circadian rhythm) and the interindividual variability (sex, age, genetics factors), as well as the sample typology and way of storage, can be mentioned. Beside the molecular heterogeneity (C-terminal fragments, included the recently identified non-(1–84)) molecular forms which may interfere with "intact molecule" PTH methods), the factors affecting the analytical variability concern the antibody interference (anti-PTH autoandibodies and heterophilic antibodies) and particularly the calibration differences existing among the commercially available assays. In order to evaluate these differences, we performed recovery tests with both synthetic hPTH(1–84) from Bachem and recombinant hPTH(1–84) 95/646 from NIBSC. The results are similar to those recently obtained by UK-NEQAS and highlight remarkable between-method calibration differences, which are the main reason for the disagreements among PTH values obtained with different kits. On the contrary, no relationship apparently exists between the cross-reactivity with synthetic hPTH(7–84) fragment and the method bias (UK-NEQAS, 2001). Therefore the lack of an International Standard is the main obstacle to solving the problems related to PTH measurement?     

Influence of Single Experience with Intraoperative Near-Infrared Autofluorescence on Postoperative Parathyroid Insufficiency after Thyroidectomy - A Preliminary Clinical Study

Introduction: Total thyroidectomy has become the most common thyroid procedure. This treatment method results in most postoperative hypocalcemia (PH) and hypoparathyroidism (HPT) cases due to the unwitting removal of the parathyroid glands (PTGs). Near-infrared autofluorescence (NIRAF) is a new method that helps identify PTGs. This study aimed to determine whether short-term experience with intraoperative NIRAF may influence postoperative complications after thyroidectomy.Materials and methods: Overall, 65 patients who underwent thyroidectomy by one high-volume surgeon were enrolled in the study between March 2018 and August 2021. In August 2020, the surgeon performed four operations using the NIRAF device. After that experience, the technique of operating and preserving PTGs has been totally changed. Postoperative serum calcium (Ca) and parathormone (PTH) concentrations were measured. Using retrospective study analysis, we assessed the rate of PH and HPT.Results: There was no statistically significant difference in Ca (p = 0.1612) and PTH (p = 0.3590) concentrations between groups operated on before and after the NIRAF experience. The serum concentrations of Ca and PTH of all patients were positively correlated (r = 0.4074; p = 0.0022) as well as the Ca concentration and age of patients (r = 0.3292; p = 0.0116), respectively.Conclusions: These findings suggest that short-term NIRAF experience, and changing attitude to preserving PTGs does not affect thyroidectomy outcomes, even when utilized by a highly experienced high-volume thyroid surgeon. However, continuous use of NIRAF might enhance treatment outcomes, particularly for surgeons with limited experience.     

Mitt-C-regionales Parathormon in der klinischen Routine: Diagnostische Wertigkeit beim extrarenalen (primären) und renalen (sekundären) Hyperparathyreodismus

Summary The selective determination of mid-C-regional parathyroid hormone (mid-C-PTH) in combination with other laboratory parameters is a reliable tool for diagnosis and treatment of extrarenal (primary) and renal (secondary) hyperparathyroidism. Early stages, which show either high-to-normal serum calcium and elevated mid-C-PTH or increased serum calcium but normal mid-C-PTH, can be distinguished from overt hyperparathyroidism. Alkaline phosphatase (AP) activity and mid-C-regional PTH provide biochemical confirmation of histologically classified renal osteodystrophy. Since the index AP×PTH signifies osseous changes in dialysis patients at an early stage, therapeutic regimens may be altered without additional invasive procedures. After renal transplantation mid-C-PTH normalizes and serum creatinine decreases. Increased mid-C-PTH in patients with normal renal graft function reflects autonomous PTH secretion, which requires careful monitoring to prevent PTH-induced hypercalciuria.

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Abkürzungsverzeichnis AP Alkalische Phosphatase - Ca Gesamtcalcium - DFO Desferrioxamin - HPT Hyperparathyreodismus - Index (AP×PTH) Produkt aus Mitt-C-PTH und AP - Mitt-C-PTH Mitt-C-regionales PTH - MW Molekulargewicht - NTX Nierentransplantation - PTH Parathormon - PTX Parathyreoidektomie mit Reimplantation in den Unterarm - PO₄ Phosphat - RIA Radioimmunoassay Mit Unterstützung der Deutschen Forschungsgemeinschaft (DFG) Ju 177/1-1