Effects of continuous chelation on the instrumentation of curved canals with a martensitic NiTi file system: an ex vivo micro-CT evaluation.

This study aimed to evaluate the influence of continuous chelation on apical transportation and centrality in shaped curved canals prepared with a martensitic file system and evaluated by micro-CT. Twenty-four lower molar canals with a curvature of 25º-40º were scanned pre-operatively with micro-CT and divided into 2 groups according to two different irrigation regimens (n = 12). Group 1 was irrigated with NaOCl, group 2 with Dual Rinse. All canals were prepared with VDW.ROTATE system. The samples were scanned post-operatively and evaluated at 1, 3 and 5 mm from the apex to determine apical transportation and canal centrality using VG Studio software. Statistical analysis was performed with SPSS software using the non-parametric Mann-Whitney test. No statistically significant differences were found between the two groups for both apical transportation and canal centrality at any of the levels studied (p < 05). The use of continuous chelation during the instrumentation of the canals with martensitic alloy files does not produce greater transportation and does not generate changes in centralization compared to NaOCl-only irrigation. Combined chelation and disinfection while shaping with martensitic NiTi can simplify the irrigation regimen without inducing iatrogenic aberrations.

Impact of circulating bacterial DNA in long-term glucose homeostasis in non-diabetic patients with HIV infection: cohort study.

In HIV-infected patients, the damage in the gut mucosal immune system is not completely restored after antiretroviral therapy (ART). It results in microbial translocation, which could influence the immune and inflammatory response. We aimed at investigating the long-term impact of bacterial-DNA translocation (bactDNA) on glucose homeostasis in an HIV population. This was a cohort study in HIV-infected patients whereby inclusion criteria were: patients with age >18 years, ART-naïve or on effective ART (<50 HIV-1 RNA copies/mL) and without diabetes or chronic hepatitis C. Primary outcome was the change in HbA1c (%). Explanatory variables at baseline were: bactDNA (qualitatively detected in blood samples by PCR [broad-range PCR] and gene 16SrRNA - prokaryote), ART exposure, HOMA-R and a dynamic test HOMA-CIGMA [continuous infusion of glucose with model assessment], hepatic steatosis (hepatic triglyceride content - 1H-MRS), visceral fat / subcutaneous ratio and inflammatory markers. Fifty-four men (age 43.2 ± 8.3 years, BMI 24.9 ± 3 kg/m2, mean duration of HIV infection of 8.1 ± 5.3 years) were included. Baseline HbA1c was 4.4 ± 0.4% and baseline presence of BactDNA in six patients. After 8.5 ± 0.5 years of follow-up, change in HbA1c was 1.5 ± 0.47% in patients with BactDNA vs 0.87 ± 0.3% in the rest of the sample p < 0.001. The change in Hba1c was also influenced by protease inhibitors exposure, but not by baseline indices of insulin resistance, body composition, hepatic steatosis, inflammatory markers or anthropometric changes. In non-diabetic patients with HIV infection, baseline bacterial translocation and PI exposure time were the only factors associated with long-term impaired glucose homeostasis.

Biological markers of fertility (inhibin-B) in HIV-infected men: influence of HIV infection and antiretroviral therapy.

OBJECTIVES: Inhibin B (IB) levels and the IB: follicle-stimulating hormone (FSH) ratio (IFR), biomarkers of global Sertoli cell function, show a strong relationship with male fertility. The aim of the study was to examine the prevalence of impaired fertility potential in HIV-infected men and the influence of antiretroviral therapy (ART) on fertility biomarkers. METHODS: A cross-sectional study with sequential sampling was carried out. A total of 169 clinically stable patients in a cohort of HIV-infected men undergoing regular ambulatory assessment in a tertiary hospital were included. The mean [± standard deviation (SD)] age of the patients was 42.6 ± 8.1 years, all were clinically stable, 61.5% had disease classified as Centers for Disease Control and Prevention (CDC) stage A, and were na?ve to ART or had not had any changes to ART for 6 months (91.1%). Morning baseline IB and FSH concentrations were measured using an enzyme-linked immunosorbent assay (ELISA) and an electrochemiluminescent immunoassay (ECLIA), respectively. A multivariate logistic regression model was used to identify factors associated with impaired fertility, defined as IB < 119 pg/mL or IFR < 23.5. RESULTS: The mean (± SD) IB level was 250 ± 103 pg/mL, the median [interquartile range (IQR)] FSH concentration was 5.1 (3.3-7.8) UI/L and the median (IQR) IFR was 46.1 (26.3-83.7). The prevalence of impaired fertility was 21.9% [95% confidence interval (CI) 16.3-20.7%]. Negative correlations of body mass index and waist: hip ratio with FSH and IB levels were observed (P < 0.01), while a sedentary lifestyle and previous nevirapine exposure were associated with a decreased risk of IB levels ≤ 25th percentile in multivariate analysis. Only older age, as a risk factor, and sedentary lifestyle, with a protective effect, were independently associated with impaired fertility in multivariate analysis. CONCLUSIONS: Global testicular Sertoli cell function and fertility potential, assessed indirectly through serum IB levels and IB: FSH ratio, appear to be well maintained in HIV-infected men and not damaged by ART.

Impact of vitamin D insufficiency on insulin homeostasis and beta cell function in nondiabetic male HIV-infected patients.

OBJECTIVES: Vitamin D is thought to play a role in glucose homeostasis and beta cell function. Our aim was to examine the impact of plasma 25-hydroxyvitamin D [25(OH)D] upon in vivo insulin sensitivity and beta cell function in HIV-infected male patients without diabetes. METHODS: A cross-sectional study was carried out involving a cohort of HIV-infected patients undergoing regular assessment in a tertiary hospital. Eighty-nine patients [mean (± standard deviation) age 42 ± 8 years] were included in the study: 14 patients were antiretroviral therapy (ART)-naïve, while 75 were on ART. Vitamin D insufficiency (VDI) was defined as 25(OH)D < 75 nmol/L; insulin sensitivity was determined using a 2-h continuous infusion of glucose model assessment with homeostasis (CIGMA-HOMA), using the trapezoidal model to calculate the incremental insulin and glucose areas under the curve (AUCins and AUGglu, respectively). Beta cell function was assessed using the disposition index (DI). Abdominal visceral adipose tissue (VAT) and hepatic triglyceride content (HTGC) were measured by magnetic resonance imaging (MRI) and 1-H magnetic resonance spectroscopy. Multivariate linear regression analysis was performed. RESULTS: VDI was associated with insulin resistance (IR), as indicated by a higher CIGMA-HOMA index (odds ratio 1.1) [1.01-1.2]. This association was independent of the main confounders, such as age, Centers for Disease Control and Prevention (CDC) stage, ART, lipodystrophy, body mass index, VAT:subcutaneous adipose tissue ratio and HTGC, as confirmed by multivariate analysis (B = 12.3; P = 0.01; r² = 0.7). IR in patients with VDI was compensated by an increase in insulin response. However, beta cell function was lower in the VDI subpopulation (33% decrease in DI). CONCLUSIONS: VDI in nondiabetic HIV-positive male patients is associated with impaired insulin sensitivity and a decrease in pancreatic beta cell function.

Utilidad de la tiroglobulina plasmática tras TSH humana recombinante en el cáncer diferenciado de tiroides libre de enfermedad / Utility of serum thyroglobulin determination after recombinant human thyrotropin administration in the follow-up patients with differentiated thyroid cancer without residual disease

Objetivos: Valorar la determinación de tiroglobulina (Tg) plasmática tras la administración de tirotropina (TSH) humana recombinante (TSHhr) en el seguimiento para valorar la persistencia de enfermedad o remisión del cáncer diferenciado de tiroides libre de enfermedad. Material y métodos: Estudio prospectivo en 38 pacientes con cáncer diferenciado de tiroides libres de enfermedad con concentraciones indetectables de Tg en tratamiento hormonal supresor. Se determinó la Tg, la TSH, tiroxina libre, la triyodotironina libre inicial y las 48 y las 72 h tras la administración de 0,9 mg por vía intramuscular de TSHhr, gammagrafías de extensión tumoral (GET) en situación de retirada del tratamiento hormonal supresor y ecografías cervicales. Resultados: La Tg tras TSHhr permaneció indetectable en 34 pacientes, y la ecografía y la GET resultaron negativas. En 3 pacientes se observó aumento de concentración de Tg tras TSHhr sin evidencia de enfermedad (ecografía y GET negativas) y en 1 paciente se observó un aumento de concentración de Tg tras la TSHhr, con presencia de enfermedad objetivada en la ecografía cervical y GET negativa. Conclusiones: La determinación de Tg tras TSHhr, unida a la realización de la ecografía cervical, es una prueba endocrinológica funcional útil en los pacientes con cáncer diferenciado de tiroides libre de enfermedad. Su realización evita la retirada del tratamiento hormonal supresor y la realización de GET que suponen un mayor coste económico e incapacidad para el paciente sin aportar más información relevante

Objectives: To evaluate serum thyroglobulin (Tg) determination after recombinant human thyrotropin (rhTSH) administration as screening in the follow-up of patients with differentiated thyroid cancer (DTC). Material and methods: A prospective study was performed in 38 patients with DTC without residual disease and undetectable Tg concentrations under thyroid hormone suppression therapy. Tg, thyroid-stimulating hormone, free T4, and free T3 were measured at baseline and 48 and 72 hours after administration of rhTSH (0.9 mg IM). In all patients, whole body scan (WBS) was performed after thyroid hormone withdrawal. Neck ultrasound was also performed. Results: After rhTSH administration Tg remained undetectable in 34 patients with negative neck ultrasound and WBS. Tg increased after rhTSH administration in 3 patients without evidence of active disease (negative WBS and neck ultrasound) and in 1 patient with evidence of active disease in neck ultrasound and negative WBS. Conclusions: Tg determination after rhTSH administration together with neck ultrasound is useful in the follow-up of patients with DTC and disease-free status. Tg determination avoids the need to withdraw thyroid hormone suppression and the use of other tests such as WBS, which lead to higher economic and social costs but do not provide further information in the follow-up of these patients

Técnicas de laboratorio en endocrinología clínica / Laboratory techniques in clinical endocrinology

Las técnicas de análisis hormonales han experimentado grandes avances en los últimos 30 años. El inmunoanálisis es el método más empleado en el laboratorio de endocrinología asistencial y es en el que nos vamos a centrar. El radioinmunoanálisis competitivo clásico que utilizaba anticuerpos policlonales fue sustituido en la década de los ochenta, siempre que la naturaleza del antígeno lo permitiera, por inmunoanálisis no competitivos con anticuerpos monoclonales. Estos métodos se caracterizan por una sensibilidad y una especificidad elevadas. Posteriormente, en la década de los noventa, los marcadores radiactivos fueron reemplazados por marcadores no isotópicos que hicieron posible la automatización del inmunoanálisis. Se revisan las ventajas y las limitaciones de los métodos más empleados en el presente. Las principales mejoras se reflejan en la precisión, la fiabilidad y el menor tiempo de respuesta. Entre las limitaciones cabe destacar el efecto matriz y, dentro de éste, los autoanticuerpos y los anticuerpos heterofílicos. Ambos pueden dar lugar a resultados falsamente elevados y, en algún caso, disminuidos. En conclusión, el conocimiento por parte de bioquímicos y endocrinólogos de las características y las limitaciones de los métodos utilizados es fundamental para interpretar resultados discordantes (AU)

In the last 30 years great advances have been made in the techniques used for hormone analysis. The main method used in hormone assay is immunoassay. The classical competitive radioimmunoassay used polyclonal antibodies; in the 1980s, this was replaced by noncompetitive assays, using monoclonal antibodies. These methods have high sensitivity and specificity. In the 1990s radioactive markers were replaced by nonisotopic labels, which opened the way for complete automation of immunoassays. We review the advantages and limitations of the methods that are most frequently used today. The main advantages are improved accuracy, reliability, and accelerated turnaround times for tests. The limitations include the matrix effect. Autoantibodies and heterophilic antibodies play a role in this effect and lead to falsely high and, sometimes, falsely low results. In conclusion biochemists and endocrinologists should be aware of the problems of each of the methods used in order to be able to interpret discordant results (AU)

Problemática en el diagnóstico bioquímico del déficit de secreción de hormona del crecimiento / Issues concerning the biochemical diagnosis of growth hormone deficiency

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La determinación aislada de hormona del crecimiento es un parámetro válido deseguimiento en la acromegalia / Basal growth hormone leve is a useful parameter for monitoring acromegaly

Objetivo. Evaluar la utilidad de la determinación aislada de hormona del crecimiento (GH) en la acromegalia sobre la base del estudio de secreción espontánea de GH. Pacientes y método. Se ha realizado un estudio retrospectivo que incluía un total de 24 pacientes acromegálicos a los que se había realizado un estudio de la secreción espontánea de GH durante la evaluación inicial de la acromegalia. Las muestras de sangre se obtuvieron mediante una bomba de extracción continua tipo CORMED unida a un catéter no trombogénico heparinizado y con separación de alícuotas cada 20 min. El estudio se prolongó entre 10 y 24 h. Con el total de muestras obtenidas se obtuvo un pool para determinación de la concentración integrada de GH. Para el análisis de secreción de pulsos se utilizó el programa computarizado PULSAR. Resultados. Sólo el 5,6 por ciento de la secreción total de GH ha sido pulsátil en los pacientes del presente estudio. Se ha objetivado una fuerte correlación entre la concentración integrada de GH y la concentración basal de GH (r = 0,83; p < 0,0001), así como el área bajo la curva sobre la línea 0 y la GH basal (r = 0,76. p = 0,0001). Se ha evidenciado una correlación más débil pero estadísticamente significativa entre la concentración integrada de GH e IGF1 (r = 0,42; p = 0,03).Conclusiones. En la acromegalia, la secreción de GH es predominantemente tónica. La determinación aislada de GH basal es fiel reflejo de la concentración integrada de GH, por lo que puede ser empleada en el diagnóstico y seguimiento de la enfermedad (AU)

[Usefulness of RET proto-oncogene in the diagnosis of hereditary-type medullary carcinoma of the thyroid. Correlation with surgical findings]. / Utilidad del proto-oncogen RET en el diagnóstico del carcinoma medular de tiroides de tipo hereditario. Correlación con los hallazgos quirúrgicos.

In about 25% of cases medullary thyroid carcinoma (MTC) is hereditary. In this group is possible to detect germline point mutations of the RET proto-oncogene in about 95% of the studied cases. The purpose of the present paper is to confirm the value of the RET in the screening of the hereditary MTC. We studied 43 subjects at risk for a Multiple Endocrine Neoplasia Type 2A Syndrome. RET analysis was positive for MEN 2A in 22 subjects. Fifteen of the 22 have undergone a total thyroidectomy at our facility. Histopathological study of the surgical specimens confirmed the presence of a MTC in all the cases. According with our experience. RET analysis is a 100% sensitive and specific method of hereditary MTC screening, and we think it has obvious advantages over the calcitonin tests in technical, economic and ethic aspects.

Utilidad del proto-oncogen RET en el diagnóstico del carcinoma medular de tiroides de tipo hereditario. Correlación con los hallazgos quirúrgicos / Utility of the RET prot-oncogene in the diagnosis of the hereditary medullary thyroid carcinoma. Correlation with the surgical results

Un 25 por ciento de los carcinomas medulares de tiroides (CMT) son de carácter hereditario, y en el 95 por ciento de los mismos se puede detectar una mutación en el proto-oncogen RET. El objeto de este trabajo es la evaluación del RET como método de despistaje del CMT hereditario. Se estudiaron 43 sujetos con riesgo de padecer un MEN 2A. En 22 pacientes el estudio del RET determinó la sospecha de un CMT, 15 de los cuales fueron intervenidos en nuestro hospital, confirmándose en todos ellos la existencia de un CMT. De acuerdo con nuestra experiencia quirúrgica, el despistaje familiar mediante el uso del RET es 100 por ciento sensible y específico, y aporta ventajas metodológicas, económicas y sociales sobre el empleo de la calcitonina (AU)

In about 25% of cases medullary thyroid carcinoma (MTC) is hereditary. In this group is possible to detect germline point mutations of the RET proto-oncogene in about 95% of the studied cases. The purpose of the present paper is to confirm the value of the RET in the screening of the hereditary MTC. We studied 43 subjects at risk for a Multiple Endocrine Neoplasia Type 2A Syndrome. RET analysis was positive for MEN 2A in 22 subjects. Fifteen of the 22 have undergone a total thyroidectomy at our facility. Histopathological study of the surgical specimens confirmed the presence of a MTC in all the cases. According with our experience. RET analysis is a 100% sensitive and specific method of hereditary MTC screening, and we think it has obvious advantages over the calcitonin tests in technical, economic and ethic aspects (AU)

Prevalence of macroprolactin detected by Elecsys 2010.

BACKGROUND: Macroprolactin or big-big PRL is, usually, a complex of little prolactin (PRL) with anti-PRL autoantibody. There are some patients with hyperprolactinemia showing a high proportion of serum macroprolactin. However, its clinical significance is not clear. Immunoassays used to determine PRL differ in their ability to detect macroprolactin. Moreover, in recent years, PRL assays have changed from isotopic methods (radioimmunoassays and immunoradiometric assays) to non-isotopic automated immunoassays. The effect of macroprolactin on currently used methods is often unknown. The aim of this work was to study the different reactivity of macroprolactin in two immunoassays systems, Elecsys 2010 and ACS Centaur, and to assess the clinical repercussion of this condition. METHODS: We studied retrospectively 956 consecutive routine patients. Samples with a PRL value >636 mIU/l (211 samples) were subjected to the polyethylene glycol (PEG) precipitation test to detect macroprolactin, and 2 of them also to gel filtration chromatography for further confirmation. PRL was measured by Elecsys 2010 and, alternatively, by ACS Centaur. RESULTS: By Elecsys 2010, macroprolactin was detected in 19 patients (9%). After removing macroprolactin, PRL levels were within the normal range in every case but one. When original sera from patients with macroprolactin were processed with ACS Centaur. PRL levels were normal or only marginally elevated. The correlation of PRL values in samples with and without macroprolactin assayed by both systems was 0.64 and 0.98, respectively. CONCLUSIONS: Nearly 9% of hyperprolactinemic patients detected by Elecsys 2010 may have macroprolactin, but the detection rate obtained using ACS Centaur is much lower. As macroprolactin seems to have minimal clinical relevance, it would be important that the users of PRL assays be aware to what extent macroprolactin interferes with their assays, and have available a validated method, such as the PEG precipitation test, to confirm the presence of macroprolactin.

[The validation of a portable 3-channel recording system (Oxyflow, Edentec) for the diagnosis of the sleep apnea syndrome]. / Validación de un sistema portátil de registro de tres canales (Oxyflow, Edentec) para el diagnóstico del síndrome de apnea del sueño.

OBJECTIVE: To evaluate the usefulness of a portable recording device (Oxyflow, EdenTec) to measure oronasal airflow, oxygen saturation and arterial pulse for diagnosing sleep apnea syndrome (SAS) using conventional polysomnography as the gold standard. METHODS: Sixty-two subjects suspected of having SAS were studied prospectively by simultaneously recording conventional polysomnography and Oxyflow data in the sleep laboratory. Two different investigators, blinded to each other's findings, interpreted the data from each method. The apnea-hypopnea index (AHI) cut-off points used were?? 10, 15 and 30. The sensitivity, specificity, positive predictive value and negative predictive value of the Oxyflow indices for each AHI cut-off point were calculated. Both computer-generated and manually collected data from the Oxyflow device were analyzed. Manual readings were recorded by two independent investigators and interobserver agreement was calculated. The usefulness of both automatic and manual analyses for SAS diagnosis was assessed using receiver operating characteristic curves (ROC). RESULTS: Fifty-eight (93.5%) men and 4 (6.5%) women with a mean age (+/- SD) of 53 +/- 11 years (29-73) were enrolled. An AHI > or = 10 was observed in 58% of the patients and mean AHI was 25 +/- 28 (0-125). The index of respiratory disturbance per hour of analysis with desaturation events > or = 4% (RDI4%) was the parameter with the largest area under the ROC curve (0.90 for AHI > or = 10; 0.94 for AHI > or = 15 and 0.96 for AHI > or 30). Manual reading was practical and reproducible (agreement 0.93, kappa coefficient 0.82) but its efficiency was no greater than that of automatic analysis. CONCLUSIONS: The Oxyflow device may be a useful diagnostic tool for SAS. Its portability and simplicity makes it potentially useful for in-home studies.

Validación de un sistema portátil de registro de tres canales (Oxyflow, Edentec) para el diagnóstico del síndrome de apnea del sueño / Validation of a portable three-channel recording system (Oxyflow, EdenTec) for diagnosing sleep apnea syndrome

Objetivo: Evaluar la utilidad de un sistema de registro portátil (Oxyflow, Edentec), que mide flujo nasobucal, saturación de oxígeno y pulso arterial, para el diagnóstico del síndrome de apnea del sueño (SAS), utilizando la polisomnografía convencional como patrón de referencia. Métodos: Se estudiaron prospectivamente 62 sujetos con sospecha de SAS, realizándose simultáneamente polisomnografía convencional y registro con Oxyflow en el laboratorio de sueño. Dos investigadores diferentes interpretaron los registros de cada uno de los métodos, a ciegas respecto al otro. Se utilizaron diferentes puntos de corte para el índice de apneas-hipopneas (IAH) (>= 10, 15 y 30). Se calcularon la sensibilidad, especificidad, valor predictivo positivo y valor predicto negativo de los índices del Oxyflow para cada punto de corte del IAH. Al analizar los registros del Oxyflow, se emplearon tanto datos generados por el software incluido en el sistema como los obtenidos con una interpretación manual de los mismos. El análisis manual fue realizado por dos investigadores independientes, y se calculó la concordancia interobservador. La utilidad del análisis manual y el automático para el diagnóstico del SAS fue evaluado usando curvas receptor-operador (ROC). Resultados: Se incluyeron en el estudio 58 varones (93,5 por ciento) y 4 mujeres (6,5 por ciento), con una edad media (ñ DE) de 53 ñ 11 años (29-73). El 58 por ciento de los pacientes tenían un IAH >= 10 (IAH medio: 25 ñ 28 [0-125]). De todos los parámetros analizados, el RDI4 por ciento (índice de episodios respiratorios por hora de registro, con desaturaciones >= 4 por ciento) presentó el mayor área bajo la curva ROC (0,90 para IAH >= 10; 0,94 para IAH >= 15 y 0,96 para IAH >= 30). El análisis manual fue factible y reproducible (concordancia: 0,93; coeficiente kappa: 0,82), pero su eficiencia no fue mayor que la del análisis automático. Conclusiones: El sistema Oxyflow puede ser una herramienta útil para el diagnóstico del SAS. Su portabilidad y simplicidad lo hacen potencialmente útil para estudios domiciliarios. (AU)

Insulin, androgens, and obesity in women with and without polycystic ovary syndrome: a heterogeneous group of disorders.

OBJECTIVE: To analyze the correlations among insulin, androgens, body mass index (BMI), and other related metabolic anomalies in women with and without polycystic ovary syndrome (PCOS). DESIGN: Retrospective study of normal and obese women with and without PCOS. SETTING: Gynecologic endocrinology units of Elche, San Juan, and Alicante Hospitals and Hormone Laboratory at Alicante University Hospital ("Miguel Hernández" University). PATIENT(S): A total of 212 women were studied: 137 with PCOS and 75 without PCOS. INTERVENTION(S): BMI, gonadotropins, insulin, androgens (T, androstenedione, DHEAS), 17alpha-hydroxyprogesterone, sex hormone-binding globulin, and triglycerides were studied. Glycemia and insulin response to the tolerance test (GTT) with a 100-g oral glucose load were also assessed in 103 women. RESULT(S): A good correlation between insulin and BMI was found in normal and obese women without hormonal dysfunction and in patients with or without PCOS. Good correlations, although lower, between insulin and T, and BMI, insulin, and T with triglycerides were also found in patients with PCOS. These patients fell into clearly distinct categories: with or without insulin resistance and with or without obesity, but slim women with PCOS had insulin and metabolic variables similar to those without PCOS, and most obese women with PCOS were insulin-resistant and more hyperandrogenic and hypertriglyceridemic. CONCLUSION(S): Insulin, androgens, and BMI are related in women both with PCOS and without PCOS, especially in obese ones. Insulin and metabolic indices are similar in lean women with PCOS and those without PCOS, but obese women with PCOS are more insulin-resistant, hyperandrogenic, and hypertriglyceridemic. Three types of disorders can be distinguished: simple nonhyperandrogenic obesity, typical nonhyperinsulinemic PCOS, and insulin-resistant PCOS.

Analytical and clinical evaluation of TSH and thyroid hormones by electrochemiluminescent immunoassays.

OBJECTIVES: To perform an analytical evaluation of the new electrochemiluminescent immunoassays (ECLIA) for TSH, FT4, and T3 in the Elecsys 2010 immunoassay system. To assess the clinical classification of patients under suspicion of thyroid disease based on these laboratory assays. MATERIALS AND METHODS: The analytical evaluation included the performance of minimum detectable concentrations, within-assay and inter-assay precision for the three analytes, functional sensitivity and linearity studies for TSH, and method comparison with the previous methods of RIA for FT4 and T3, and IRMA for TSH in current protocols of our institution. 102 patients with clinical suspicion of thyroid disease were assayed by ECLIA and radioactive techniques. Their differential clinical classification based on laboratory tests was studied as well. RESULTS: The minimum detectable concentrations coincided with the manufacturer's: <0.005 mU/L for TSH, <0.30 pmol/L for FT4, and <0.30 nmol/L for T3. Functional sensitivity for TSH was 0.044 mU/L. Over the analytical range tested, within-assay imprecision was below 3.2% for TSH, 2.2% for FT4 and 9.6% for T3, and interassay CVs were below 4.0% for TSH, 5.9% for FT4 and 12.9% for T3. Measurement of diluted sera showed the TSH assay to overestimate recoveries by 18.6%. We have compared sera results of the Elecsys ECLIA assays with those obtained from the IRMA (Spectria-Orion Diagnostica) for TSH: TSH (ECLIA) = 0.074+0.953 TSH (IRMA), (r = 0.974; Sy/x = 2.638), and RIA (Coat a Count-DPC) for FT4:FT4 (ECLIA) = 5.043+0.682 FT4 (RIA), (r = 0.770; Sy/x = 4.774) and RIA (Spectria-Orion Diagnostica) for T3: T3(ECLIA) = -0.461+1.084 T3 (RIA), (r = 0.970; Sy/x = 0.412). When sera from 102 patients were processed by both methods, minimal disagreement in the area of diagnostic classification was observed in 8/102 (7.8%) of the cases. CONCLUSION: The Elecsys 2010 is specially attractive as a routine assay because it is fully automated, obtaining results in only 18 minutes. The analytical assay performance for TSH, FT4 and T3 was shown to be acceptable. Using two different sets of diagnostic tests minimal discrepancies were found in the laboratory assessment for the classification of patients with clinical suspicion of thyroid disease.

Influence of anti-insulin antibodies on insulin immunoassays in the autoimmune insulin syndrome.

The autoimmune insulin syndrome (AIS) is a rare, benign syndrome characterized by hyperinsulinaemia and hypoglycaemia associated with the presence of autoantibodies to insulin in patients who have not been treated with insulin. We report here the case of a 52-year-old patient with recurrent attacks of severe postprandial hypoglycaemia and we also present the effect of anti-insulin antibodies on insulin immunoassays. The patient was submitted to the following diagnostic tests: 5-h oral glucose tolerance test (OGTT), a prolonged 72-h fast and an insulin tolerance test (ITT). Serum glucose, total and free insulin, C-peptide, proinsulin, insulin antibodies and other autoantibodies were measured. Insulin concentrations were measured by two methods: a double antibody radioimmunoassay (RIA) and an immunoradiometric assay (IRMA). Insulin concentration measured by RIA was extremely high in the OGTT and 72-h fast. In contrast, insulin concentrations measured by IRMA were between 120 and 888 pmol/L in the OGTT and between 37 and 133 pmol/L during the 72-h fast. Fasting free-insulin concentrations measured by RIA were between 2224 and 2669 pmol/L, whereas free-insulin concentrations measured by IRMA ranged between 93 and 237 pmol/L. Total insulin concentrations measured by RIA and IRMA were 57,615 and 94,021 pmol/L, respectively. The C-peptide concentrations were moderately high in the three tests. Serum insulin antibody concentrations were extremely high (62-71%), compared with less than 3% in normal serum samples. In conclusion, the high insulin concentrations measured by RIA were caused by insulin autoantibodies. However, insulin concentrations measured by IRMA were not influenced by them. We conclude that IRMA is the more accurate method for measuring insulin concentrations in such cases.

Usefulness of urinary growth hormone (GH) measurement for evaluating endogenous GH secretion in acromegaly.

We investigated the relationship between urinary growth hormone (u-GH) and spontaneous 24-hour plasma GH secretion in 15 acromegalic patients. To measure u-GH, we have developed a method based on concentrating the sample by centrifugal ultrafiltration and then performing an immunoradiometric assay using commercially available reagents. u-GH correlated well with the integrated concentration of plasma GH (r = 0.66, p < 0.02). Additionally, u-GH excretion in acromegalic patients was significantly higher than in the control group (190 +/- 100 vs. 3.89 +/- 0.56 pg/min, mean +/- SEM, p < 0.001). Immunoreactive u-GH showed the same elution pattern in Sephadex G-75 as standard or labeled hGH, proving that the substance measured in urine is authentic GH. In conclusion, u-GH appears to be a simple, noninvasive and inexpensive test for evaluating GH secretion in active acromegaly.