Anti-ruthenium antibodies mimic macro-TSH in electrochemiluminescent immunoassay.

BACKGROUND: Macro-hormones are circulating conjugates of hormones with immunoglobulins, which often artefactually elevate biochemical test results. Particularly when causing only moderate elevation no suspicion will be raised. By far the most frequently encountered macro-hormone is macro-prolactin. Here we report a female patient with rheumatoid arthritis who had persistently and grossly elevated thyroid stimulating hormone (TSH) but normal free thyroxine in electrochemiluminescent assays. Although clinically euthyroid, she was put on thyroxine therapy which caused hyperthyroid symptoms. METHODS: An analytic interference by macro-TSH was assumed by dilution experiments, polyethylene-glycol-precipitation, the addition of a heterophilic antibody blocking reagent and size exclusion chromatography. RESULTS: Further workup, however, revealed the presence of anti-ruthenium antibodies. CONCLUSIONS: To our knowledge this is the first report of anti-ruthenium antibodies selectively interfering with a TSH assay and causing erratic gross elevation of TSH mimicking macro-TSH.

Risk factors for "PTH spikes" during surgery for primary hyperparathyroidism.

PURPOSE: Increased intraoperative parathyroid hormone excretion ("PTH spikes") due to unintended manipulation of parathyroid adenoma can be observed frequently during surgery for primary hyperparathyroidism. This may lead to difficulties in interpreting intraoperative PTH curves. The aim of this study was to elucidate possible risk factors for PTH spikes and to evaluate the impact on different interpretation criteria of intraoperative PTH curves. METHODS: Eight hundred forty-seven patients with primary hyperparathyroidism were included. The probability of PTH spikes was analyzed regarding preoperative PTH- and creatinine levels, and size of adenoma and their impact on the Vienna, Miami, and Halle criteria was evaluated. RESULTS: PTH spikes occurred in 102 patients (12 %) and revealed to be independent of PTH- and creatinine levels (p = 0.13) preoperatively. There was a significant negative correlation between "manipulation PTH" and "baseline PTH" values and the gland volume, respectively. Patients presenting with smaller adenomas and those with low-baseline PTH values show significantly higher manipulation values. No risk factor for manipulation was exposed and no significantly higher risk of misclassification as "false positive" in case of PTH spikes was detected for any interpretation criterion. For the "Vienna Criterion," however, a significant increase in the risk of "false negative" misclassification was observed with increasing manipulation values. CONCLUSIONS: In patients with PTH spikes, none of the analyzed criteria show a significant increase in missed adenomas. Nevertheless, the Vienna criterion shows a higher rate of potentially unnecessary explorations with increasing manipulation values. Thus, caution is warranted in detecting PTH spikes and in individual interpretations of specific PTH curves is recommended. The Miami criterion seems to be favorable in this group of patients.

Inorganic phosphate and FGF-23 predict outcome in stable systolic heart failure.

BACKGROUND: Recent studies show associations between inorganic phosphate and risk of heart failure in the general population as well as between fibroblast growth factor 23 (FGF-23) and outcome in coronary heart disease. This study was carried out to assess whether circulating levels of inorganic phosphate and FGF-23, a new central hormone in mineral bone metabolism, predict outcome in systolic heart failure. MATERIALS AND METHODS: Ninety-nine consecutive outpatients with systolic heart failure were enrolled. Mean (SD) age was 61 years (11), mean left ventricular ejection fraction (LVEF) was 33% (10), 82 patients were men, median estimated creatinine clearance was 83 mL/min (Q(1) -Q(3) 58-106), median NTproBNP level was 803 pg/mL (Q(1) -Q(3) 404-2757), median inorganic phosphate was 1·12 mM (Q(1) -Q(3) 1·02-1·22), median FGF-23 was 39·02 pg/mL (Q(1) -Q(3) 32·45-55·86) and median follow-up was 35 months. Associations between inorganic phosphate, FGF-23 and endpoints were assessed using Cox regression analyses. RESULTS: Inorganic phosphate and FGF-23 levels were significantly higher (P < 0·001 and P = 0·009) in patients reaching the combined endpoint of cardiac hospitalization or death. FGF-23 (ln) predicted all-cause mortality (hazard ratio (HR) 5·042, P = 0·032) in a model adjusted for age, gender, estimated creatinine clearance, LVEF, New York Heart Association (NYHA) stage and NTproBNP level. Inorganic phosphate predicted heart failure hospitalization (HR 26·944, P = 0·021), cardiac hospitalization (HR 16·016, P = 0·017) and the combined endpoint (HR 13·294, P = 0·015) in models adjusted for the same co-variables. CONCLUSION: The results of this study demonstrate the independent prognostic value of inorganic phosphate and FGF-23 in heart failure even in the context of established risk markers.

Sclerostin serum levels correlate positively with bone mineral density and microarchitecture in haemodialysis patients.

BACKGROUND: Sclerostin is a soluble inhibitor of osteoblast function. Sclerostin is downregulated by the parathyroid hormone (PTH). Here, it was investigated whether sclerostin levels are influenced by intact (i) PTH and whether sclerostin is associated with bone turnover, microarchitecture and mass in dialysis patients. METHODS: Seventy-six haemodialysis patients and 45 healthy controls were included in this cross-sectional study. Sclerostin, Dickkopf-1 (DKK-1), intact parathyroid hormone (iPTH), vitamin D and markers of bone turnover were analysed. A subset of 37 dialysis patients had measurements of bone mineral density (BMD) using dual-energy X-ray absorptiometry and bone microarchitecture using high-resolution peripheral quantitative computed tomography. RESULTS: Dialysis patients had significantly higher sclerostin levels than controls (1257 pg/mL versus 415 pg/mL, P < 0.001). Significant correlations were found between sclerostin and gender (R = 0.41), iPTH (R = -0.28), 25-hydroxy-cholecalciferol (R = 0.27) and calcium (R = 0.25). Gender and iPTH remained significantly associated with sclerostin in a multivariate analysis. Sclerostin serum levels were positively associated with BMD at the lumbar spine (R = 0.46), femoral neck (R = 0.36) and distal radius (R = 0.42) and correlated positively mainly with trabecular structures such as trabecular density and number at the radius and tibia in dialysis patients. DKK-1 was related neither to bone measures nor to serologic parameters. CONCLUSIONS: Considering that sclerostin is an inhibitor of bone formation, the observed positive correlations of serum sclerostin with BMD and bone volume were unexpected. Whether its increase in dialysis patients has direct pathogenetic relevance or is only a secondary phenomenon remains to be seen.

Biomarkers of bone turnover in diagnosis and therapy of osteoporosis: a consensus advice from an Austrian working group.

AIM: Reasonable application of laboratory parameters in prevention, diagnosis, treatment and therapy monitoring of osteoporosis. TARGET GROUPS: Physicians from different specialist disciplines (general medicine, geriatrics, gynaecology, urology, internal medicine-especially endocrinology and metabolism, nephrology, laboratory medicine, rheumatology, nuclear medicine, orthopaedics, paediatrics, rehabilitation and physical medicine, radiology, social medicine, transplantation medicine, accident surgery), moreover social insurances, hospitals and self-help groups. BACKGROUND: Evaluation of aetiology of bone disorders, widening of the therapeutic spectrum for diseases of bone and knowledge on biochemical markers of bone turnover. Improvements in judging the success of therapy and in monitoring the compliance of patients. Research perspectives. BASES: Scientific literature and guidelines, consensus meetings. RÉSUMÉ: Basic and specialized laboratory investigations are important in differentiation between primary and secondary osteoporosis for an adequate therapy. Biochemical markers of bone turnover are an additional aid in evaluation of individual fracture risk. These markers identify responders to bone therapy faster than surveillance of bone mineral density, which helps to improve patient's compliance too. Characteristics, preanalytic precautions and applications are presented for selected markers of bone resorption and formation and for parameters regulating bone metabolism.

Reciprocal role of GATA-1 and vitamin D receptor in human myeloid dendritic cell differentiation.

Two major pathways of human myeloid dendritic cell (DC) subset differentiation have previously been delineated. Langerhans cells (LCs) reside in epithelia in the steady state, whereas monocytes can provide dendritic cells (DCs) on demand in response to inflammatory signals. Both DC subset pathways arise from shared CD14+ monocyte precursors, which in turn develop from myeloid committed progenitor cells. However, the underlying hematopoietic mechanisms still remain poorly defined. Here, we demonstrate that the vitamin D(3) receptor (VDR) is induced by transforming growth factor beta1 during LC lineage commitment and exerts a positive role during LC generation. In contrast, VDR is repressed during interleukin-4 (IL-4)-dependent monocyte-derived DC (moDC) differentiation. We identified GATA-1 as a repressor of VDR. GATA-1 is induced by IL-4 in moDCs. Forced inducible expression of GATA-1 mimics IL-4 in redirecting moDC differentiation and vice versa, GATA-1 knockdown arrests moDC differentiation at the monocyte stage. Moreover, ectopic GATA-1 expression stabilizes the moDC phenotype under monocyte-promoting conditions in the presence of vitamin D3 (VD3). In summary, human myeloid DC subset differentiation is inversely regulated by GATA-1 and VDR. GATA-1 mediates the repression of VDR and enables IL-4-dependent moDC differentiation. Conversely, VDR is induced downstream of transforming growth factor beta1 and is functionally involved in promoting LC differentiation.

Anti-Mullerian hormone levels decline under hormonal suppression: a prospective analysis in fertile women after delivery.

BACKGROUND: AMH's reported stability during periods of hormonal change makes it a practical tool in assessing ovarian reserve. However, AMH declines with age and age-specific cut-offs remain to be established in women with proven fertility. This study aims to determine age-specific ranges of AMH in women with proven fertility. METHODS: Two hundred-ten fertile women, aged 18-40 years, were prospectively recruited for AMH measurements within 14 days after delivery and age stratified into 3 groups (18-30, 31-36 and 37-40 years). Eligibility required spontaneous conception within a maximal period of six months. Autoimmune diseases, chemotherapy, radiation, ovarian surgery and polycystic ovary syndrome precluded inclusion. RESULTS: 95% confidence intervals of AMH declined with advancing female age from 0.9-1.1 to 0.6-0.9 and 0.2-0.4 ng/mL (P < 0.001). AMH levels were not statistically associated with day of blood draw after delivery or pregnancy characteristics. Neither were they predictive of resumption of menses. They, however, at all ages were lower than reported in the literature for infertile patients. CONCLUSIONS: Like infertile populations, fertile women demonstrate declining AMH with advancing age. Uniformly lower levels than in infertile women suggest that AMH levels do not appear as stable under all hormonal influences as previously reported.

A simple micro-photometric method for urinary iodine determination.

BACKGROUND: Urinary iodide concentration (UIC) is useful to evaluate nutritional iodine status. In clinical settings UIC helps to exclude blocking of the thyroid gland by excessive endogenous iodine, if diagnostic or therapeutic administration of radio-iodine is indicated. Therefore, this study established a simple test for the measurement of UIC. METHODS: UIC was analyzed in urine samples of 200 patients. Samples were pre-treated at 95°C for 45 min with ammonium persulfate in a thermal cycler, followed by a photometric Sandell-Kolthoff reaction (SK) carried out in microtiter plates. For method comparison, UIC was analyzed in 30 samples by inductivity coupled plasma mass spectro-metry (ICP-MS) as a reference method. RESULTS: Incubation conditions were optimized concerning recovery. The photometric test correlated well to the reference method (SK=0.91*ICP-MS+1, r=0.962) and presented with a functional sensitivity of 20 µg/L. UIC of patient samples ranged from <20 to 750 µg/L (median 110 µg/L); 90% of the urine samples had iodide concentrations below 210 µg/L. CONCLUSION: The modified SK-test takes approximately 90 min for analyses of 20 urine samples compared with 27 h for ICP-MS. The photometric test provides satisfactory results and can be performed with the basic equipment of a clinical laboratory.

Impact of spinach consumption on DNA stability in peripheral lymphocytes and on biochemical blood parameters: results of a human intervention trial.

INTRODUCTION: A controlled intervention trial was conducted to assess the impact of spinach consumption on DNA stability in lymphocytes and on health-related biochemical parameters. METHODS: The participants (n = 8) consumed homogenised spinach (225 g/day/person) over a period of 16 days. DNA migration was monitored in single cell gel electrophoresis-comet assays under standard conditions, which reflect single- and double-strand breaks, after treatment of nuclei with lesion-specific enzymes (formamidopyrimidine glycosylase, FPG and endonuclease III, ENDO III) and after treatment of intact cells with H(2)O(2) before, during and after intervention. RESULTS: While no reduction in DNA damage was observed under standard conditions after different time intervals of spinach intake, other endpoints, namely ROS sensitivity and DNA migration attributable to the formation of oxidatively damaged DNA bases (i.e. pyrimidines-ENDO III-sensitive sites and purines-FPG sensitive sites) were reduced 6 h after consumption of the first portion and after 11 days of continuous consumption. In the case of ENDO III-sensitive sites, also after 16 days, a decrease in comet formation was observed. At the end of a 40 days washout period, the DNA stability parameters were not significantly different from the background values. Other biochemical parameters which were significantly altered by spinach intake were the folate (+27%) and homocysteine (-16%) concentrations in blood, and it was found in an earlier human study that folate may prevent oxidative damage to DNA bases. CONCLUSIONS: Taken together, our results show that moderate consumption of spinach causes protection against oxidative DNA damage in humans and that this phenomenon is paralleled by alterations of health-related biochemical parameters.

Parathyroid Hormone Concentrations in Maintenance Hemodialysis: Longitudinal Evaluation of Intact and Biointact Assays.

RATIONALE & OBJECTIVE: Management of chronic kidney disease mineral and bone disorder requires parathyroid hormone (PTH) concentrations. "Biointact" PTH immunoassays detect "whole" PTH (wPTH), whereas "intact" immunoassays measure PTH plus PTH fragments (iPTH). We aimed to determine whether longitudinal changes in PTH concentrations can be evaluated using biointact and intact immunoassays alike. STUDY DESIGN: Open noninterventional longitudinal cohort study. SETTING & PARTICIPANTS: PTH concentrations were measured quarterly up to 5 times in 102 hemodialysis patients. PREDICTORS & TESTS COMPARED: Age, sex, phosphate levels, and others as clinical predictors for PTH trend. Tests compared were iPTH immunoassays from Siemens and Roche and wPTH immunoassays from Roche and DiaSorin. OUTCOMES: PTH concentration trend; regression equations; test bias. ANALYTICAL APPROACH: Predictive regression-to-the-mean model for PTH slope; Bland-Altman plots, Passing-Bablok regression, and reference change values for test comparisons. RESULTS: wPTH concentrations were similar with both immunoassays (wPTH-Roche = 11.7 + 0.97 × wPTH-DiaSorin, r = 0.99; mean ± 1.96 SD bias, 8.2 ± 43.3 pg/mL [17.5% ± 40.9%], by Bland-Altman plots). iPTH-Siemens concentrations were higher than iPTH-Roche concentrations (iPTH-Siemens = -5.4 + 1.33 × iPTH-Roche, r = 0.99; mean ± 1.96 SD bias, 84.0 ± 180.2 pg/mL [21.1% ± 29.8%], by Bland-Altman plots). iPTH-Roche and iPTH-Siemens concentrations were 2- and 2.5-fold higher than wPTH concentrations, respectively. Full agreement among all 4 immunoassays in detecting both significant and insignificant changes in PTH concentrations, upward or downward from one quarter to the next, was reached in 87% of consecutive measurements. In a predictive model, baseline PTH concentrations > 199 pg/mL (wPTH-Roche), 204 pg/mL (wPTH-DiaSorin), 386 pg/mL (iPTH-Roche), and 417 pg/mL (iPTH-Siemens) correctly predicted declining PTH concentration trend in 62% to 68% of patients, but age, sex, hemodialysis vintage, and calcium and phosphate levels were no significant predictors. LIMITATIONS: Limited number of immunoassays, only 59 patients attended all quarterly samplings. CONCLUSIONS: wPTH-Roche and wPTH-DiaSorin concentrations were similar, while iPTH was higher than wPTH concentrations. The iPTH-Siemens immunoassay is either higher calibrated or detects more fragments than iPTH-Roche. However, longitudinal PTH concentration changes largely coincided with all tested immunoassays.

Is minimally invasive parathyroidectomy without QPTH monitoring justified?

BACKGROUND: It is matter of discussion if quick parathyroid hormone (QPTH) monitoring is helpful in patients with primary hyperparathyroidism (PHPT) and "localized single-gland disease" (SGD; concordant sestamibi and ultrasound results) to further increase the rate of success (permanent normocalcemia) of performing selective parathyroidectomy by minimally invasive parathyroid exploration (MIP). The aim of this study was to evaluate if a randomized controlled trial was justified in order to clarify this discussion. MATERIALS AND METHODS: The prospective database of patients with sporadic PHPT, SGD, MIP, and QPTH monitoring (1999-2005) was evaluated regarding the "conversion rate" to bilateral exploration and permanent normocalcemia ("QPTH" group). Retrospectively, the patients were analyzed a second time "without" applying QPTH monitoring ("non-QPTH" group). Statistical differences between both groups were calculated (McNemar's test). RESULTS: By definition, 338 patients with "localized SGD" underwent MIP. MIP was finished in 308 (91.1%) patients. Five of 308 patients (1.6%) showed persisting (n = 1) or recurrent disease (n = 4). In 30 of 338 patients (8.9%), a conversion to bilateral exploration was necessary (false preoperative localization 15 patients--one patient not cured; multiple-gland disease correctly indicated by QPTH monitoring 15 patients--one patient not cured). Analyzing the "non-QPTH" group, 14 additional patients showed persisting disease. Thus, without using QPTH monitoring, the rate of persisting PHPT would increase from 0.9% (three patients) to 5.0% (17 patients; p = 0.0005). CONCLUSION: Intraoperative QPTH assay seems necessary even in patients with "localized SGD" by two techniques in an endemic goiter region. Abandoning QPTH monitoring would more than double the rate of persisting disease. A randomized trial seems not to be justified.

PTH secretion of "manipulated" parathyroid adenomas.

PURPOSE: Increased secretion of parathyroid hormone (PTH) and its fragments intraoperatively may influence PTH monitoring. The purpose of this study was to investigate whether "intended intraoperative manipulation" of parathyroid adenomas through mechanical stimulation (through squeezing or manual rubbing) would lead to increased PTH excretion. The different PTH fragments that result from this kind of manipulation were correlated and analyzed. METHODS: The enlarged glands of six consecutive patients who underwent open minimally invasive parathyroid exploration were "manipulated" for 30 s as soon as they had been identified. Blood samples were drawn before skin incision, at the beginning of the manipulation, 30 s, and at 2-, 5-, 10-, and 15-min intervals. Serum levels of (1-84)PTH were measured and (7-84)PTH was calculated. RESULTS: An increased PTH secretion was documented in four of six "manipulated" single adenomas (mean PTH +/- SD 312 +/- 497 pg/ml). The PTH of one patient rose from 343 to 1,747 pg/ml. The ratio of (1-84)PTH to (7-84)PTH was 1.3 +/- 0.6 (median +/- SD):1 at "baseline" and 1.4 +/- 0.2:1 after manipulation. The coefficient of determination (R(2)) for the "baseline values" and for the values after manipulation is R(2) = 0.9816 and R(2) = 0.9985, respectively. CONCLUSIONS: First, secretion of PTH varies widely after manual manipulation of adenomas. Second, PTH fragments circulate in the same ratio before and after "manipulation."

Chronic heart failure leads to an expanded plasma volume and pseudoanaemia, but does not lead to a reduction in the body's red cell volume.

Aims Chronic heart failure (CHF) is frequently associated with a decreased haemoglobin level, whereas the mechanism remains largely unknown. Methods and results One hundred consecutive CHF patients without anaemia or renal dysfunction based on non-cardiac reasons were enrolled. We explored determinants of anaemia (as iron parameters, erythropoietin, hepcidin and kidney function) including red cell volume (RCV) (by a 51 Cr assay) as well as related markers and plasma volume. The influence of each factor on haemoglobin concentrations was determined in a multiple regression model. Mean haemoglobin concentrations were 11.7 +/- 0.8 mg/dL in anaemic CHF patients and 14.4 +/- 1.2 mg/dL in non-anaemic patients. Corrected reticulocytes were lower in anaemic patients (35.1 +/- 15.7 vs. 50.3 +/- 19.2 G/L, P = 0.001), but the RCV was not reduced (1659.3 +/- 517.6 vs. 1826.4 +/- 641.3 mL, P = 0.194). We found that plasma volumes were significantly higher in anaemic CHF patients (70.0 +/- 2.4 vs. 65.0 +/- 4.0%, P < 0.001). Plasma volume was the best predictor of haemoglobin concentrations in the regression model applied (B = -0.651, P < 0.001, R(2) = 0.769). Conclusion Haemodilution appears to be the most potent factor for the development of low haemoglobin levels in patients with CHF. Our data support an additional independent, but minor influence of iron deficiency on haemoglobin concentrations in CHF patients.

Glucocorticoids in the treatment of children with acute lymphoblastic leukemia and hodgkin's disease: a pilot study on the adverse psychological reactions and possible associations with neurobiological, endocrine, and genetic markers.

PURPOSE: We did a controlled study to assess adverse psychological reactions (APR) associated with high-dose glucocorticoid therapy and tried to detect somatic correlates for the observed reactions. PATIENTS AND METHODS: Our study included 37 patients with acute lymphoblastic leukemia (ALL) and 11 patients with Morbus Hodgkin (MH) disease, who were treated with high-dose glucocorticoid therapy, and 26 control patients with other types of malignancies. APRs were assessed with a standardized measure via parent-report. Patients with ALL and MH were further analyzed for signs of neuronal cell death in the cerebrospinal fluid, polymorphisms of the glucocorticoid receptor gene, as well as cortisol, adrenocorticorticotropic hormone, and dehydroepiandrosterone sulfate blood levels. RESULTS: Fifty-four percent of ALL, 36% of MH, and 23% of control patients developed APR in the first few weeks of therapy. Approximately 3.5 months later, the majority of patients with ALL showed no APR, similar to control patients. Patients demonstrating a higher, nonsuppressible secretion of cortisol and/or adrenocorticorticotropic hormone during glucocorticoid therapy were found to be more likely to develop APR. No sign of neuronal cell destruction and no correlation of APR with specific glucocorticoid receptor polymorphisms were found. CONCLUSION: Our results suggest that the development of APR due to glucocorticoid therapy is measurable and correlates with hormonal reaction patterns.

Calcium-stimulated calcitonin - The "new standard" in the diagnosis of thyroid C-cell disease - clinically relevant gender-specific cut-off levels for an "old test".

INTRODUCTION: Pentagastrin (Pg) stimulated calcitonin (sCT) was used to enhance accuracy in medullary thyroid cancer (MTC) diagnosis. As it is now unavailable, calcium (Ca) has been recommended as an alternative. The aim of this study was to define gender-specific cut-off values to predict MTC in patients with elevated basal CT (bCT) following Pg-sCT and Ca-sCT stimulation and to compare the time courses of CT release during stimulation. MATERIALS AND METHODS: The stimulation tests were applied in 62 consecutive patients with thyroid nodules. Basal calcitonin was measured by chemiluminescent immunometric assay. All patients underwent thyroidectomy and bilateral central neck dissection. C-cell pathology was confirmed by histological and immunohistochemical evaluation. RESULTS: In 39 (0.63) patients MTC was documented while isolated C-cell hyperplasia (CCH) was identified in 23 (0.37) patients. Medullary thyroid cancer was predicted in males with bCT values > 43 pg/mL or sCT concentrations > 470 pg/mL (Pg-sCT) or > 1500 pg/mL (Ca-sCT), and in females with bCT concentrations > 23 pg/mL or sCT concentrations > 200 pg/mL (Pg-sCT) or > 780 pg/mL (Ca-sCT), respectively. Pg-sCT correctly predicted MTC in 16 (0.66) compared to 13 (0.54) after Ca-sCT in males and in 12 (0.80) compared to 11 (0.73) in females; without statistical significance. In patients with CCH or low tumor burden, there was a tendency of faster CT release after Ca stimulation (CT peak after 3min in > 60%) compared to patients with advanced MTC (CT peak after 3min in < 10%). CONCLUSIONS: Using gender-specific cut-off values, Ca could replace Pg to predict MTC with similar diagnostic power.

A "defined baseline" in PTH monitoring increases surgical success in patients with multiple gland disease.

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

The value of intraoperative pentagastrin testing in medullary thyroid cancer.

BACKGROUND: The decrease of calcitonin levels after curative operation in patients with medullary thyroid cancer is characterized by individual variation; therefore, intraoperative calcitonin measurements to evaluate the completeness of the resection seem to not be feasible. The aim of this study was to evaluate whether an intraoperative pentagastrin test after thyroidectomy and central neck dissection is useful to predict lymph node involvement of the lateral neck. METHODS: A group of 30 consecutive patients underwent primary surgery. After thyroidectomy and dissection of the central lymph node compartment, an intraoperative pentagastrin test was performed. Biochemical and histologic data were compared retrospectively. RESULTS: Of the group, 20 patients (67%) showed no, or only central neck lymph node, involvement and no increase in calcitonin after intraoperative stimulation. Lymph node involvement was documented histologically in the lateral neck of 10 patients (33%), and 8 patients showed an increase of calcitonin as an indication of lymph node involvement. In two patients, each with 1 single micrometastasis in the lateral neck, the intraoperative pentagastrin test was negative. CONCLUSIONS: Intraoperative calcitonin monitoring after pentagastrin stimulation seems promising in predicting lymph node involvement of the lateral neck to aid selection of patients for lateral lymph node dissection. The development of a highly sensitive, quick calcitonin assay is imperative.

Roche Elecsys Prolactin II assay: reactivity with macroprolactin compared with eight commercial assays for prolactin and determination of monomeric prolactin by precipitation with polyethylene glycol.

Hyperprolactinaemia due to macroprolactin (MPRL) can lead to misdiagnosis and inappropriate treatment. We studied the new Roche Elecsys Prolactin assay (PRL II) which has been developed to reduce reactivity with MPRL. We investigated the performance of the PRL II assay at six laboratory sites to determine precision and establish reference intervals for total immunoreactive PRL and for monomeric PRL determined by precipitation with polyethylene glycol (PEG). We compared the reactivities with macroprolactin of the PRL II, the PRL I and seven other PRL assays. The PRL II assay reacted less strongly than the PRL I assay and similarly to the ADVIA Centaur assay with macroprolactin. PEG precipitation can be used with the PRL II assay to estimate the concentration of monomeric PRL.

Roche Elecsys Prolactin II assay: reactivity with macroprolactin compared with eight commercial assays for prolactin and determination of monomeric prolactin by precipitation with polyethylene glycol.

Hyperprolactinaemia due to macroprolactin (MPRL) can lead to misdiagnosis and inappropriate treatment. We studied the new Roche Elecsys Prolactin assay (PRL II) which has been developed to reduce reactivity with MPRL. We investigated the performance of the PRL II assay at six laboratory sites to determine precision and establish reference intervals for total immunoreactive PRL and for monomeric PRL determined by precipitation with polyethylene glycol (PEG). We compared the reactivities with macroprolactin of the PRL II, the PRL I and seven other PRL assays. The PRL II assay reacted less strongly than the PRL I assay and similarly to the ADVIA Centaur assay with macroprolactin. PEG precipitation can be used with the PRL II assay to estimate the concentration of monomeric PRL.

Increased plasma amylin in type 1 diabetic patients after kidney and pancreas transplantation: A sign of impaired beta-cell function?

OBJECTIVE: In response to hyperglycemia, beta-cells release insulin and C-peptide, as well as islet amyloid pancreatic polypeptide, which is involved in glucose homeostasis. After successful pancreas-kidney transplantation (PKT), type 1 diabetic patients may revert to a nondiabetic metabolism without exogenous insulin therapy and re-secrete all beta-cell hormones. RESEARCH DESIGN AND METHODS: Using mathematical models, we investigated hormone (amylin, insulin, C-peptide) and metabolite (glucose, free fatty acids) kinetics, beta-cell sensitivity to glucose, and oral glucose insulin sensitivity index (OGIS) in 11 nondiabetic type 1 diabetic patients after PKT (BMI 25 +/- 1 kg/m2, 47 +/- 2 years of age, 4 women/7 men, glucocorticoid-free), 6 matching nondiabetic patients after kidney transplantation (25 +/- 1 kg/m2, 50 +/- 5 years, 3 women/3 men, on glucocorticoids), and 9 matching nondiabetic control subjects (24 +/- 1 kg/m2, 47 +/- 2 years, 4 women/5 men) during a 3-h 75-g oral glucose tolerance test (OGTT). RESULTS: PKT patients had higher fasting amylin (19 +/- 3 vs. control subjects: 7 +/- 1 pmol/l) and insulin (20 +/- 2 vs. control subjects: 10 +/- 1 microU/ml; each P < 0.01) levels. Kidney transplant subjects showed increased OGTT plasma insulin at 90 min and C-peptide levels (each P < 0.05). In PKT patients, plasma glucose from 90 to 150 min was 9-31% higher (P < 0.05 vs. control subjects). Amylin clearance was comparable in all groups. Amylin's plasma concentrations and area under the concentration curve were up to twofold higher in PKT patients during OGTT (P < 0.05). OGIS was not significantly different between groups. beta-Cell sensitivity to glucose was reduced in PKT patients (-64%, P < 0.009). Fasting plasma amylin was inversely associated with beta-cell sensitivity to glucose (r = -0.543, P < 0.004). CONCLUSIONS: After successful PKT, type 1 diabetic patients with nondiabetic glycemia exhibit increased fasting and post-glucose load plasma amylin, which appears to be linked to impaired beta-cell function. Thus, higher amylin release in proportion to insulin might also reflect impaired beta-cell function in type 1 diabetic patients after PKT.