Calcitonin levels by ECLIA correlate well with RIA values in higher range but are affected by sex, TgAb, and renal function in lower range.

Calcitonin (CT) is a marker for both initial diagnosis and monitoring of patients with residual or recurrent medullary thyroid carcinoma (MTC). In Japan, serum CT had been measured by radioimmunoassay (RIA) until recently. Electrochemiluminescence immunoassay (ECLIA) became commercially available in 2014, and this technique is now the only method used to examine CT concentration. The purposes of this study were to investigate the correlations between the CT concentration measured with ECLIA (ECLIA-CT) and RIA (RIA-CT) and to explore the clinical characteristics of patients with elevated ECLIA-CT. CT concentrations of 348 sera samples from 334 patients with various thyroid disorders including nine MTC were measured using both assays. The correlation analysis revealed an excellent correlation between ECLIA-CT and RIA-CT among the cases with CT level >150 pg/mL by both assays (rs = 0.991, p < 0.001). However, 63% of all samples exhibited undetectable ECLIA-CT, while their RIA-CTs were measured between 15 and 152 pg/mL. The ECLIA-CTs in all patients who underwent total thyroidectomy for non-MTC showed low concentrations. High ECLIA-CT was observed in patients with MTC or pancreas neuroendocrine tumor. ECLIA-CT was also increased in 14 other male patients with non-MTC, including four with renal failure. Multivariate logistic regression analysis showed that male sex, negative TgAb, and lower estimated glomerular filtration rate were independent factors to predict detectable ECLIA-CT (≥0.500 pg/mL). These results indicate that ECLIA-CT correlates well with RIA-CT in higher range and is affected by sex, TgAb, and renal function.

Calcitonin measurement in pediatrics: reference ranges are gender-dependent, validation in medullary thyroid cancer and thyroid diseases.

BACKGROUND: There is only limited information on serum reference ranges of calcitonin (CT) in infants, children and adolescents. This gap hampers valid diagnostics in patients with multiple endocrine neoplasia type 2 (MEN 2) and planned prophylactic thyroidectomy. In addition, age-dependent reference ranges for CT are necessary to define a cure in medullary thyroid carcinoma (MTC). We asked whether the reference ranges for CT levels were age- and gender-dependent in the serum of a pediatric cohort. METHODS: A total of 6090 serum samples of 2639 subjects of the LIFE-Child cohort aged between 1 month and 17.9 years were analyzed by the CT electrochemiluminescence immunoassay (ECLIA). Reference intervals were estimated using the LMS method. For clinical validation the serum of 28 patients (61 samples) with MEN 2 and 106 patients (136 samples) with thyroid diseases were analyzed. RESULTS: CT levels showed a clear age- and gender-dependence with significantly higher values in boys (p<0.01). An accelerated decline of CT levels from newborn to children at the age of 4 and 5 years was observed for both sexes. A cure for MTC was demonstrated in 71% of MEN 2 patients after thyroidectomy, whereas 5 patients remained suspicious for micrometastasis or relapse. Only 1.5% of our patients with thyroid diseases revealed increased CT levels. CONCLUSIONS: This is the largest study to establish novel pediatric reference ranges from the CT values of healthy subjects. It allows a precise laboratory monitoring of CT in pediatric patients with MEN 2. Thyroid diseases did not have a relevant influence on CT levels in our pediatric cohort.

Higher cut-off serum procalcitonin level for sepsis diagnosis in metastatic solid tumor patients.

OBJECTIVE: The current study aimed to know procalcitonin levels in patients with metastatic tumor, and to discover the cut-off point for sepsis in this population. A cross-sectional study was conducted with patients with solid tumor. Sepsis and systemic inflammation response syndrome (SIRS) were identified using clinical, laboratory, and microbiological criteria. The cut-off point was determined using receiver operating characteristic (ROC) curve. RESULTS: A total of 112 subjects enrolled in this study, 51% male, mean age 47.9 ± 12.47 years. Among 71 (63.4%) patients who had metastasis, 36 (32.1%) had sepsis and 6 (5.3%) experienced SIRS. In the absence of sepsis, the procalcitonin levels were significantly higher in patients with metastatic tumor compared to those without [0.25 ng/mL (0.07-1.76) vs. 0.09 ng/mL (0.03-0.54); p < 0.001]. The ROC curve showed that levels of procalcitonin for sepsis in metastatic solid tumors were in the area under curve (AUC) [0.956; CI 0.916-0.996]. Cut-off point of procalcitonin for sepsis was 1.14 ng/mL, Sn 86%, and Sp 88%. Thus, the results show that metastatic tumor affects the patients' procalcitonin level, even in the absence of sepsis. The cut-off point of procalcitonin level for diagnosing sepsis in the meta-static solid tumor was higher compared to the standard value.

Cómo convencer al jefe de servicio y al gerente de la importancia de las unidades/consultas especializadas de cefaleas / How to convince the head of department and managing director of the importance of specialised headache clinics

A pesar de que la cefalea es, con diferencia, el principal motivo neurológico de consulta, y de la complejidad diagnóstica y terapéutica de algunos pacientes, el número de consultas monográficas de cefalea (CC) y de unidades de cefalea (UC) es muy reducido en nuestro país. En este artículo pasaremos revista a los principales argumentos que nos permitan, como neurólogos, defender la necesidad de la implementación de una CC/UC, dependiendo de la población que se debe atender, en todos nuestros servicios de neurología. Para ello deberemos, en primer lugar, vencer las reticencias internas, que hacen que la cefalea sea aún poco apreciada y atractiva dentro de nuestra especialidad. El hecho de que la cefalea justifique más de un cuarto de las consultas a un servicio de neurología estándar de nuestro país y de que existan más de 200 cefaleas diferentes, algunas de ellas realmente invalidantes, y las nuevas opciones de tratamiento para pacientes crónicos, como la OnabotulinumtoxinA para la migraña crónica o las técnicas de neuromodulación, obligan a introducir dentro de nuestras carteras de servicios la asistencia especializada en cefaleas. Aunque no disponemos de datos incontrovertibles, existen ya datos suficientes en la literatura que indican que esta atención es eficiente en pacientes con cefaleas crónicas no sólo en términos de salud, sino también desde el punto de vista económico (AU)

In spite that headache is, by far, the most frequent reason for neurological consultation and that the diagnosis and treatment of some patients with headache is difficult, the number of headache clinics is scarce in our country. In this paper the main arguments which should allow us, as neurologists, to defend the necessity of implementing headache clinics are reviewed. To get this aim we should first overcome our internal reluctances, which still make headache as scarcely appreciated within our specialty. The facts that more than a quarter of consultations to our Neurology Services are due to headache, that there are more than 200 different headaches, some of them actually invalidating, and the new therapeutic options for chronic patients, such as OnabotulinumtoxinA or neuromodulation techniques, oblige us to introduce specialised headache attendance in our current neurological offer. Even though there are no definite data, available results indicate that headache clinics are efficient in patients with chronic headaches, not only in terms of health benefit but also from an economical point of view (AU)

Liquid Chromatography-High Resolution Mass Spectrometry for Peptide Drug Quality Control.

A liquid chromatography-high resolution mass spectrometry (LC-HRMS) method was developed using three peptide drugs: salmon calcitonin, bivalirudin, and exenatide as model systems to assess the suitability of this approach for monitoring peptide drug product quality. Calcitonin and its related impurities displayed linear responses over the range from 0.1 to 10 µM (R (2) values for calcitonin salmon, Glu(14)-calcitonin, and acetyl-calcitonin were 0.995, 0.996, and 0.993, respectively). Intra-assay precision in terms of relative standard deviation (%RSD) was less than 10% at all tested concentrations. The accuracy of the method was greater than 85% as measured by spiking 0.1, 0.3, and 1% of Glu(14)-calcitonin and acetyl-calcitonin into a stock calcitonin solution. Limits of detection for calcitonin, Glu(14)-calcitonin, and acetyl-calcitonin were 0.02, 0.03, and 0.04 µM, respectively, indicating that an impurity present at less than 0.1% (0.1 µM) of the drug product API concentration (107 µM) could be detected. Method validation studies analyzing bivalirudin and exenatide drug products exhibited similar results to calcitonin salmon in regard to high selectivity, sensitivity, precision, and linearity. Added benefits of using LC-HRMS-based methods are the ability to also determine amino acid composition, confirm peptide sequence, and quantify impurities, even when they are co-eluting, within a single experiment. LC-HRMS represents a promising approach for the quality control of peptides including the measurement of any peptide-related impurities. While the development work performed here is focus on peptide drug products, the principles could be adapted to peptide drug substance.

Umbilical cord blood serum procalcitonin by Time-Resolved Amplified Cryptate Emission (TRACE) technology: reference values of a potential marker of vertically transmitted neonatal sepsis.

BACKGROUND: Neonatal infection remains a major diagnostic problem because of non-specific clinical signs and symptoms, as well as low sensitivity and specificity of routine laboratory tests. C-reactive protein (CRP), white blood cell count, absolute neutrophil count and immature/total neutrophil ratio are the most widely used tests in the diagnosis of sepsis and provide useful information, but none of these has demonstrated to be reliable in detecting all septic infants. Procalcitonin (PCT) has been suggested as a potentially useful laboratory test performed in umbilical cord blood when perinatal bacterial sepsis is under investigation. METHODS: In this study, the reference interval for umbilical cord blood serum PCT was established for the first time by Time-Resolved Amplified Cryptate Emission (TRACE) technology. RESULTS: The reference interval for PCT in umbilical cord blood serum ranged from 0.04 to 0.43 microg/L in 168 non-infected newborn infants (95% CI 0.02-0.06 and 0.35-0.60 microg/L, respectively). Cord blood serum PCT correctly classified one infected patient out of 90 newborn infants at risk of vertically transmitted sepsis and identified another neonate as a potentially infected patient despite having negative blood cultures. However, cord blood CRP misclassified 21 out of the 90 patients as infected neonates. CONCLUSIONS: Cord blood PCT measured by TRACE is a potentially more useful early marker of neonatal sepsis than cord blood CRP.

The FDA's assessment of follow-on protein products: a historical perspective.

The scientific and regulatory issues that are associated with the possible introduction of 'follow-on' versions of protein drug products are the topic of considerable debate at present. Because of the differences between protein drug products and small-molecule drugs, the development of follow-on versions of protein products presents more complex scientific challenges than those presented by the development of generic versions of small-molecule drugs. Here, with a view to illustrating the Food and Drug Administration's (FDA's) scientific reasoning and experience in this area, we discuss past examples of the FDA's actions involving the evaluation of various types of follow-on and second-generation protein products and within-product manufacturing changes. The FDA believes its evaluation of the safety and effectiveness of follow-on protein products will evolve as scientific and technological advances in product characterization and manufacturing continue to reduce some of the complexity and uncertainty that are inherent in the manufacturing of protein products.

Multicenter collaborative study to calibrate salmon calcitonin by bioassay and high-performance liquid chromatography: establishment of the third international standard.

Salmon calcitonin (sCT) is widely used therapeutically in the treatment of patients with postmenopausal osteoporosis, Paget's disease, and some forms of hypercalcemia. Preparations of synthetic calcitonin peptides of high purity and reproducibility are now routinely produced and physicochemical methods, particularly reverse-phase high-performance liquid chromatography (RP-HPLC), are replacing the in vivo biological assay for monitoring and calibration. Although the bioassay is no longer required for routine batch control in Europe, calcitonin bioassays are still required in some countries and in the development of new products. Stocks of the Second International Standard (IS) for salmon calcitonin are now depleted and, to replace it with a new calibrant, an international collaborative study was organized in which the aims were to: determine the activity of the candidate sCT by in vivo bioassay in terms of the second IS; assess the stability of the preparation after accelerated thermal degradation; estimate the purity of the ampouled candidate preparation; and determine the sCT content in gravimetric units by HPLC. The HPLC data in terms of ampoule content were in good agreement giving an estimate of 23.1 (coefficient of variation [CV] 3.8%) microg per ampoule. The HPLC chromatograms revealed a small, but detectable, degree of heterogeneity, which possibly occurred during the formulating or ampouling procedures, resulting in a reduction in monocomponent content (purity) from 96% to 92%. The biological activity of the ampoule contents in international units (IU) was calculated from the mass value and the internationally agreed-upon figure of 6000 IU/per mg for the specific activity of salmon calcitonin. This gave a value of 138 IU per ampoule, which was in good agreement with the biological assay estimate (140 IU per ampoule). The preparation of sCT was subsequently adopted as the Third International Standard by the World Health Organization with an assigned content of 138 IU per ampoule.

[Elcatonin Reference Standard (Control 921) of National Institute of Health Sciences].

The raw material of elcatonin was examined for preparation of the "Elcatonin Reference Standard". The candidate material was evaluated by a domestic collaborative study in which five laboratories participated. The biological activity was determined to be 11.3 Unit/Amp. against the International Elcatonin Reference Standard (Code 84/614), based on one hour hypocalcaemia rat bioassay. In spite of the differences in rat strain, sex, administration method, dosage and assay method for serum calcium etc., the separately obtained biological activities for the candidate agreed closely with each other (95% confidence limits 11.08-11.53 Unit/Amp.). The physico-chemical evaluation of the candidate material was also performed, by using HPLC and amino acid chromatography. Based on the above results, this raw material was authorized to be the Elcatonin Reference Standard of the National Institute of Health Sciences.

Establishment of the second international standards for porcine and human calcitonins: report of the international collaborative study.

The biological potency of calcitonins in clinical use in long-term treatment of Paget's disease of bone and, increasingly, in osteoporosis is usually expressed international units defined by the relevant World Health Organization international reference preparation. The international reference preparations for porcine and human calcitonins were ampouled in 1970 and stocks are now exhausted. Replacement standards were ampouled in 1989 and have been evaluated and calibrated by an international collaborative study comprising 16 laboratories in 12 countries. Evaluations included high-performance liquid chromatography and in vitro bioassay; calibration of each new ampouled preparation in terms of its international reference preparation was by in vivo rat hypocalcaemia bioassay. On the basis of the results of the study and with the agreement of the participants, replacement standards were established by the Expert Committee on Biological Standardization of the World Health Organization in 1991: the international standard for porcine calcitonin (ampoule code 89/540), with an assigned potency of 0.8 international units per ampoule, and the international standard for human calcitonin, with an assigned potency of 17.5 international units per ampoule. Both international standards appeared to be sufficiently stable to serve as the international standards for in vivo biological assays. Comparison of the two species of calcitonin in the same hypocalcaemia assay showed that they were approximately equipotent when the doses were given intravenously but that the human peptide was four- to sixfold more potent than porcine calcitonin when doses were given subcutaneously, emphasizing the need to compare "like with like".

Nasal human calcitonin for tumor-induced hypercalcemia.

We treated four hypercalcemic cancer patients by nasal hCT, 3 x 2 mg daily, which has been reported to be active in Paget's disease at lower doses. Only one patient became normocalcemic and mean (+/- SEM) calcium levels fell from 11.6 +/- 0.2 mg/dl before therapy to 10.7 +/- 0.6 mg/dl 2-3 days after starting hCT. The tolerance was excellent but, because of insufficient efficacy, we do not recommend this form of therapy for cancer hypercalcemia.

Clinical efficacy of salmon calcitonin in Paget's disease of bone.

Clinical interest in salmon calcitonin began in 1972 when this peptide was shown to be effective in the treatment of Paget's disease. Salmon calcitonin is more potent than porcine calcitonin, with human calcitonin intermediate in potency. Salmon calcitonin is a highly effective therapeutic agent in the treatment of Paget's disease. During chronic treatment with salmon calcitonin, alkaline phosphatase activity and urinary hydroxyproline excretion decrease on an average of 50% in patients with Paget's disease. Patients may experience a variety of clinical benefits during chronic treatment, including relief of bone pain, a reversal of neurological deficits, stabilization or improvement of hearing loss, and improvement of vascularity of bone. Radiologic healing of osteolytic lesions in particularly striking with calcitonin treatment. Paget's disease patients prefer treatment with salmon calcitonin administered by means of a nasal spray. Salmon calcitonin has an excellent safety profile and produces mild side effects in a small percentage of patients. The most common side effects associated with salmon calcitonin administration are nausea and facial flushing. It is unusual to observe severe side effects. In about 20% of patients, production of antibodies may neutralize the effects of the exogenously administered calcitonin; these patients respond to human calcitonin. At this time salmon calcitonin should still be considered a valuable therapeutic agent in the treatment of Paget's disease, particularly in patients with osteolytic lesions.

International Standards for salmon calcitonin, eel calcitonin, and the Asu1-7 analogue of eel calcitonin: calibration by international collaborative study.

Regulatory specifications in most countries require that the potency of salmon calcitonin (sCT) clinical products be expressed in International Units (IU) defined by the World Health Organization (WHO) International Standard. The first ampouled standard was prepared in 1972 and has been distributed world-wide since then. A batch of ampoules to serve as the replacement standard is now required. Other piscine calcitonins, eel calcitonin (eCT) and an amino-suberic acid analogue of eCT (Asu1-7 eCT) are now clinical products in some countries and international standards are required for these peptides which are similar to, but not identical with, sCT. This paper describes the preparation of three new ampouled standards and their biological calibration by international collaborative study comprising 17 participants from 10 countries. Following the recommendations in the final report of the collaborative study, the 2nd International Standard (IS) for sCT, the 1st IS for eCT and the 1st IS for Asu1-7 eCT were recently established by WHO, each with an assigned potency in IU, and are now available for issue.

A highly specific and sensitive enzyme-immunometric assay for calcitonin gene-related peptide based on enzyme amplification.

Calcitonin gene-related peptide (CGRP) is an important member of the peptide family encoded by the calcitonin gene. It has been found to be a potent vasodilator in man and a major circulating gene product (Girgis et al., 1985). The present study reports the development of a sensitive and rapid two-site immunoassay for CGRP based on enzyme amplification (Self, 1985). The assay has been easy to construct, taking advantage of available antisera raised for other purposes. Nevertheless it has been found to be clearly superior to our previous radioimmunoassay in terms of sensitivity, specificity, speed and convenience.

The international reference preparation of calcitonin, human, for bioassay: assessment of material and definition of the international unit.

An international reference material is required for bioassays of preparations of synthetic human calcitonin for administration to man and for use in immunoassays. A preparation of synthetic human calcitonin in ampoules coded 70/234 (previously widely used as the MRC Research Standard) has been examined in an international collaborative study involving 7 laboratories in 6 countries. The results of 34 in vivo bioassays with two other preparations of synthetic human calcitonin showed that this preparation was suitable to serve as a standard. With the agreement of the participants in the collaborative study, the batch of ampoules, code 70/234, was established in 1978 by the World Health Organization as the International Reference Preparation of Calcitonin, Human, for Bioassay. The International Unit of human calcitonin was defined as the activity contained in one ampoule of this preparation, thus maintaining continuity of the unit of the research standard.