RESUMO
PURPOSE: The aims of this study were to assess the role of an in-house competitive thyroglobulin assay (Tg-c) in the follow-up of metastatic differentiated thyroid carcinoma (DTC) patients who presented underestimated Tg measurements by immunometric assays (Tg-IMA) and to compare the results with IMA and LC-MS/MS Tg methods. METHODS: This prospective study included 40 patients. Twenty-one with metastatic disease: 14 had Tg-IMA levels inappropriately low or undetectable (eight patients with positive and six with borderline TgAb) and seven had high Tg-IMA levels. Nineteen had an excellent response to therapy. The competitive assay employs a polyclonal antibody produced in rabbits immunized with human Tg, Tg labeled with biotin, and for the solid phase separation, a monoclonal anti-rabbit IgG antibody adsorbed to microtiter plates. RESULTS: All 14 patients with structural disease and underestimated levels of Tg-IMA presented detectable Tg-c levels. The median Tg-c level in the group with positive TgAb was 183 µg/L (range: 22-710 µg/L), and 58 µg/L (range 23-148 µg/L) in the borderline TgAb group. The levels of Tg-LC-MS/MS were detectable in some patients (range < 0.5-18 µg/L). All seven patients with high Tg-IMA presented also high levels of Tg-c. Only 2/19 patients with excellent response had Tg-c levels above the functional sensitivity. CONCLUSIONS: The competitive assay was able to detect Tg in all patients, even in the presence of serum TgAb, and may be an option in patients with underestimated Tg-IMA and relevant structural disease.
Assuntos
Tireoglobulina , Neoplasias da Glândula Tireoide , Animais , Autoanticorpos , Cromatografia Líquida , Seguimentos , Humanos , Estudos Prospectivos , Coelhos , Espectrometria de Massas em TandemRESUMO
Thyroid Stimulating Hormone (TSH) levels are related to the pituitary gland's ability to detect thyroid hormone concentration. Many studies have analyzed the correlation between TSH and T4, demonstrating a complex system correlation. This complex system may vary among different TSH levels and patients. OBJECTIVES: The main purpose of this study is to assess the correlation and agreement of serum TSH measured with two assays in different settings. DESIGN & METHODS: We evaluated healthy individuals as well as subclinical or overt hypothyroid patients. Eighty participants had TSH levels measured by Cobas Roche Elecsys 600 (Roche Diagnostics) and Abbott Architect I 2000 (Abbott Diagnostics). The TSH methods correlations were established with Pearson's correlation, and the strength of the agreement was determined by the McBride scale. The paired Student's t-test was applied to evaluate TSH values from both methods. The one-sample t-test was used to evaluate the difference between TSH values. The agreement was also assessed by a Bland-Altman plot. A regression analysis was applied to the correlation between TSH and T4. RESULTS: There was a significant difference in TSH values measured by the two methods (p<0.01). Our results demonstrated a poor correlation for TSH in the euthyroid (r: 0.888, p<0.01) and the subclinical hypothyroid (r:0.886, p<0.01) range. The Bland-Altman plot demonstrates that the majority of the TSH values fell between the lines of equality. There were few differences in the values in the normal upper range and slightly above that range (from a TSH: 3.25 to 6.36mUI/L). The level of correlation between TSH assays remains high in all scenarios for age (r≥0.951), BMI (r≥0.962), anti-TPO antibodies (r: 0.977) or levothyroxine use (r: 0.970). CONCLUSIONS: TSH measurement is essential to access thyroid function. Although the overall agreement between the methods is substantial, there was a poor agreement in the normal upper range and close above. The disagreement observed reinforces the difficulty in using different assays in clinical practice. The better correlation with fT4 and the reference range used by Cobas assay allowed the best clinical performance.
Assuntos
Análise Química do Sangue/métodos , Hipotireoidismo/sangue , Tireotropina/sangue , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos ProspectivosRESUMO
Measuring thyroid hormones is an important aspect for the study of metabolism and for monitoring diseases in both human and animal models. The traditional method for hormone measurement in rats is the radioimmunoassay (RIA). However, the RIA is associated with some practical disadvantages, including the use of radioactive material, the need for specialized equipment and expert staff, the short shelf-life of kits according to the half-life of the radioisotope and high costs. The objective of this study was to develop a new cost-effective method for measuring TSH levels in rats that avoids the use of radioactive material. We developed an in-house competitive immunoassay using a reference standard, polyclonal antibody produced in rabbits and biotinylated antigen. This method was tested in 64 Wistar rats that were divided into a control group (n = 41) and a group with hypothyroidism (n = 23). Our assay demonstrated an analytical sensitivity of 0.24 ng/mL (n = 12) and an intra-assay coefficient of variation (CV) of 8.9% for sera with TSH levels of 1.5 ng/mL and 13.2% for sera with TSH levels of 17.5 ng/mL (n = 14). The inter-assay CV was 13.5% for sera with TSH levels of 1.4 ng/mL and 14.5% for TSH levels of 18.2 ng/mL (n = 5). The analysis of mean TSH levels in control rats (5.06 ± 0.5701) and hypothyroid rats (51.09 ± 5.136) revealed a statistically significant difference (p < 0.001) between the groups. This method showed good sensitivity, can be automated and is low-cost compared with RIA. Our method offers a viable alternative for TSH measurement in rats.
Assuntos
Imunoensaio/métodos , Doenças da Glândula Tireoide/diagnóstico , Tireotropina/sangue , Animais , Análise Custo-Benefício , Imunoensaio/economia , Masculino , Coelhos , Ratos , Ratos Wistar , Sensibilidade e Especificidade , Doenças da Glândula Tireoide/sangueRESUMO
ABSTRACT Measuring thyroid hormones is an important aspect for the study of metabolism and for monitoring diseases in both human and animal models. The traditional method for hormone measurement in rats is the radioimmunoassay (RIA). However, the RIA is associated with some practical disadvantages, including the use of radioactive material, the need for specialized equipment and expert staff, the short shelf-life of kits according to the half-life of the radioisotope and high costs. The objective of this study was to develop a new cost-effective method for measuring TSH levels in rats that avoids the use of radioactive material. We developed an in-house competitive immunoassay using a reference standard, polyclonal antibody produced in rabbits and biotinylated antigen. This method was tested in 64 Wistar rats that were divided into a control group (n = 41) and a group with hypothyroidism (n = 23). Our assay demonstrated an analytical sensitivity of 0.24 ng/mL (n = 12) and an intra-assay coefficient of variation (CV) of 8.9% for sera with TSH levels of 1.5 ng/mL and 13.2% for sera with TSH levels of 17.5 ng/mL (n = 14). The inter-assay CV was 13.5% for sera with TSH levels of 1.4 ng/mL and 14.5% for TSH levels of 18.2 ng/mL (n = 5). The analysis of mean TSH levels in control rats (5.06 ± 0.5701) and hypothyroid rats (51.09 ± 5.136) revealed a statistically significant difference (p < 0.001) between the groups. This method showed good sensitivity, can be automated and is low-cost compared with RIA. Our method offers a viable alternative for TSH measurement in rats.
Assuntos
Animais , Masculino , Coelhos , Ratos , Doenças da Glândula Tireoide/diagnóstico , Imunoensaio/métodos , Tireotropina/sangue , Doenças da Glândula Tireoide/sangue , Imunoensaio/economia , Sensibilidade e Especificidade , Análise Custo-Benefício , Ratos WistarRESUMO
ABSTRACT Objectives The presence of thyroglobulin (Tg) in needle washouts of fine needle aspiration biopsy (Tg-FNAB) in neck lymph nodes (LNs) suspected of metastasis has become a cornerstone in the follow-up of patients with papillary thyroid carcinoma (PTC). However, there are limited data regarding the measurement of anti-Tg antibodies in these washouts (TgAb-FNAB), and it is not clear whether these antibodies interfere with the assessment of Tg-FNAB or whether there are other factors that would more consistently justify the finding of low Tg-FNAB in metastatic LNs. Materials and methods We investigated 232 FNAB samples obtained from suspicious neck LNs of 144 PTC patients. These samples were divided according to the patient’s serum TgAb status: sTgAb- (n = 203 samples) and sTgAb+ (n = 29). The TgAb-FNAB levels were measured using two different assays. Tg-FNAB was also measured using two assays when low levels (< 10 ng/mL) were identified in the first assay of the metastatic LNs from the sTgAb+ samples. Results The TgAb-FNAB results were negative in both assays in all samples. Low levels of Tg-FNAB were identified in 11/16 of the metastatic LNs of the sTgAb+ patients and 16/63 of the sTgAb- patients (p < 0.05) using assay 1. The measurement of the Tg-FNAB levels using assay 2 indicated additional metastases in 5 LNs of the sTgAb+ patients. Conclusions Factors other than the presence of TgAb-FNAB may contribute to the higher number of metastatic LNs with undetectable Tg-FNAB in the sTgAb+ group. In addition, the measurement of Tg-FNAB using different assays was useful to enhance the diagnosis of metastatic LNs, particularly when cytological and Tg-FNAB results are discordant.
Assuntos
Humanos , Autoanticorpos/sangue , Tireoglobulina/sangue , Neoplasias da Glândula Tireoide/sangue , Carcinoma/sangue , Linfonodos/imunologia , Valores de Referência , Carcinoma/imunologia , Carcinoma/patologia , Carcinoma Papilar , Fluorimunoensaio/métodos , Valor Preditivo dos Testes , Biópsia por Agulha Fina/instrumentação , Biópsia por Agulha Fina/métodos , Linfonodos/patologia , Metástase Linfática/imunologia , Metástase Linfática/patologia , PescoçoRESUMO
OBJECTIVES: The presence of thyroglobulin (Tg) in needle washouts of fine needle aspiration biopsy (Tg-FNAB) in neck lymph nodes (LNs) suspected of metastasis has become a cornerstone in the follow-up of patients with papillary thyroid carcinoma (PTC). However, there are limited data regarding the measurement of anti-Tg antibodies in these washouts (TgAb-FNAB), and it is not clear whether these antibodies interfere with the assessment of Tg-FNAB or whether there are other factors that would more consistently justify the finding of low Tg-FNAB in metastatic LNs. MATERIALS AND METHODS: We investigated 232 FNAB samples obtained from suspicious neck LNs of 144 PTC patients. These samples were divided according to the patient's serum TgAb status: sTgAb- (n = 203 samples) and sTgAb+ (n = 29). The TgAb-FNAB levels were measured using two different assays. Tg-FNAB was also measured using two assays when low levels (< 10 ng/mL) were identified in the first assay of the metastatic LNs from the sTgAb+ samples. RESULTS: The TgAb-FNAB results were negative in both assays in all samples. Low levels of Tg-FNAB were identified in 11/16 of the metastatic LNs of the sTgAb+ patients and 16/63 of the sTgAb- patients (p < 0.05) using assay 1. The measurement of the Tg-FNAB levels using assay 2 indicated additional metastases in 5 LNs of the sTgAb+ patients. CONCLUSIONS: Factors other than the presence of TgAb-FNAB may contribute to the higher number of metastatic LNs with undetectable Tg-FNAB in the sTgAb+ group. In addition, the measurement of Tg-FNAB using different assays was useful to enhance the diagnosis of metastatic LNs, particularly when cytological and Tg-FNAB results are discordant.
Assuntos
Autoanticorpos/sangue , Carcinoma/sangue , Linfonodos/imunologia , Tireoglobulina/sangue , Neoplasias da Glândula Tireoide/sangue , Biópsia por Agulha Fina/instrumentação , Biópsia por Agulha Fina/métodos , Carcinoma/imunologia , Carcinoma/patologia , Carcinoma Papilar , Fluorimunoensaio/métodos , Humanos , Linfonodos/patologia , Metástase Linfática/imunologia , Metástase Linfática/patologia , Pescoço , Valor Preditivo dos Testes , Valores de Referência , Reprodutibilidade dos Testes , Câncer Papilífero da Tireoide , Neoplasias da Glândula Tireoide/imunologia , Neoplasias da Glândula Tireoide/patologia , UltrassonografiaRESUMO
Germline mutations in codon 918 of exon 16 of the RET gene (M918T) are classically associated with multiple endocrine neoplasia type 2B (MEN 2B) with highly aggressive medullary thyroid cancer (MTC), pheochromocytoma and a unique phenotype. The objectives of this study are to describe the rare M918V RET mutation discovered in 8 MTC kindreds from Brazil lacking the MEN 2B phenotype classically observed in M918T patients and to investigate the presence of a founder effect for this germline mutation. Eight apparently sporadic MTC cases were diagnosed with the germline M918V RET mutation. Subsequently, their relatives underwent clinical and genetic assessment (n = 113), and M918V was found in 42 of them. Until today, 20/50 M918V carriers underwent thyroidectomy and all presented MTC/C-cell hyperplasia; the remainder carriers are on clinical follow-up. None of the M918V carriers presented clinical features of MEN 2B. Their clinical presentation was heterogeneous, and the age at tumor diagnosis ranged from 24 to 59 years. Lymph node metastases were present in 12/20 patients, and presumable distant metastases in 2/20; in contrast, we observed a carrier of up to 87 years of age without evidence of MTC. Ethnographic fieldwork and haplotype analyses suggested that the founder mutation first settled in that area fifteen generations ago and originated from Portugal. Our study is the first to demonstrate the RET M918V mutation co-segregating in 8 familial MTC kindreds with validated evidence of a founder effect. We suggest that M918V MTC should be clinically considered an American Thyroid Association (ATA) moderate-risk category.
Assuntos
Substituição de Aminoácidos , Carcinoma Medular/congênito , Neoplasia Endócrina Múltipla Tipo 2a/genética , Mutação de Sentido Incorreto , Proteínas Proto-Oncogênicas c-ret/genética , Neoplasias da Glândula Tireoide/genética , Adolescente , Adulto , Idoso de 80 Anos ou mais , Brasil , Carcinoma Medular/genética , Criança , Família , Feminino , Efeito Fundador , Mutação em Linhagem Germinativa , Humanos , Masculino , Metionina/genética , Pessoa de Meia-Idade , Linhagem , Valina/genética , Adulto JovemRESUMO
Objective Consuming a low-iodine diet (LID) is a widely accepted practice before administering radioiodine (131I) to evaluate and to treat thyroid disease. Although this procedure is well established for the management of patients with differentiated thyroid cancer, its use in patients with benign disease is unclear. So, we aimed to evaluate the influence of a LID on the outcome in patients with Graves’ disease (GD) treated with131I. Subjects and methods We evaluated 67 patients with GD who were divided into 2 groups: one group (n = 31) consumed a LID for 1-2 weeks, and the second group (n = 36) was instructed to maintain a regular diet (RD). Results The LID group experienced a 23% decrease in urinary iodine after 1 week on the diet and a significant 42% decrease after 2 weeks on the diet. The majority (53%) of the patients in the LID group had urinary iodine levels that were consistent with deficient iodine intake. However, there was no difference in the rate of hyperthyroidism’s cure between the LID and the RD groups 6 months after 131I therapy. Furthermore, the therapeutic efficacy did not differ in patients with varying degrees of sufficient iodine intake (corresponding urinary iodine levels: < 10 μg/dL is deficient; 10-29.9 μg/dL is sufficient; and > 30 μg/dL is excessive). Conclusion In the present study, we demonstrated that although a LID decreased urinary iodine levels, those levels corresponding with sufficient or a mild excess in iodine intake did not compromise the therapeutic efficacy of131I for the treatment of GD.
Assuntos
Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Doença de Graves/dietoterapia , Doença de Graves/tratamento farmacológico , Radioisótopos do Iodo/uso terapêutico , Iodo/administração & dosagem , Oligoelementos/farmacologia , Terapia Combinada , Seguimentos , Alimentos Formulados , Iodo/urina , Estado Nutricional , Resultado do TratamentoRESUMO
OBJECTIVE: Consuming a low-iodine diet (LID) is a widely accepted practice before administering radioiodine (131I) to evaluate and to treat thyroid disease. Although this procedure is well established for the management of patients with differentiated thyroid cancer, its use in patients with benign disease is unclear. So, we aimed to evaluate the influence of a LID on the outcome in patients with Graves' disease (GD) treated with 131I. SUBJECTS AND METHODS: We evaluated 67 patients with GD who were divided into 2 groups: one group (n = 31) consumed a LID for 1-2 weeks, and the second group (n = 36) was instructed to maintain a regular diet (RD). RESULTS: The LID group experienced a 23% decrease in urinary iodine after 1 week on the diet and a significant 42% decrease after 2 weeks on the diet. The majority (53%) of the patients in the LID group had urinary iodine levels that were consistent with deficient iodine intake. However, there was no difference in the rate of hyperthyroidism's cure between the LID and the RD groups 6 months after 131I therapy. Furthermore, the therapeutic efficacy did not differ in patients with varying degrees of sufficient iodine intake (corresponding urinary iodine levels: < 10 µg/dL is deficient; 10-29.9 µg/dL is sufficient; and > 30 µg/dL is excessive). CONCLUSION: In the present study, we demonstrated that although a LID decreased urinary iodine levels, those levels corresponding with sufficient or a mild excess in iodine intake did not compromise the therapeutic efficacy of 131I for the treatment of GD.
Assuntos
Doença de Graves/dietoterapia , Doença de Graves/tratamento farmacológico , Radioisótopos do Iodo/uso terapêutico , Iodo/administração & dosagem , Oligoelementos/farmacologia , Adolescente , Adulto , Idoso , Terapia Combinada , Feminino , Seguimentos , Alimentos Formulados , Humanos , Iodo/urina , Masculino , Pessoa de Meia-Idade , Estado Nutricional , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: Serum calcitonin (sCT) is a useful biomarker for medullary thyroid cancer (MTC). Consensus has not been reached concerning sCT measurements in the evaluation of nodular thyroid disease (NTD). OBJECTIVE AND METHODS: We developed a new immunofluorometric assay for sCT and have validated it in samples from 794 patients [203 with MTC, 205 with autoimmune thyroid disease (ATD), 248 with NTD, 80 with differentiated thyroid cancer (DTC) 'free of disease', 58 with chronic renal failure (CRF)] and 178 normal individuals, including samples after pentagastrin tests and samples from the washout of 92 FNA procedures in patients with NTD or MTC. We also compared some samples from patients with low or high calcitonin levels using both this assay and the Nichols Institute Diagnostics (NID) assay. RESULTS: The assay's analytical sensitivity was 1.0 pg/ml. Considering MTC patients prior to surgery, the cut-off values for the 95% reference range were 11.1 pg/ml for males and 5.5 pg/ml for females and employing the ROC curve were 18.4 pg/ml for males and 7.8 pg/ml for females. sCT in patients with MTC was strongly correlated with disease status. Patients with NTD and ATD did not present false-positive results. sCT measurements were significantly correlated with age (excluding MTC and CRF). The NID test had a strong correlation with our assay. A hook effect was observed only with concentrations >200,000 pg/ml. CONCLUSIONS: We developed a novel sCT assay and validated it in healthy subjects, as well as in a large cohort of patients with MTC, NTD, ATD, DTC, and CRF.
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OBJECTIVE: Reviewing the clinical outcomes of a large kindred with a RET p.Gly533Cys mutation, 10 years after the first description of this kindred, has provided an important set of clinical data for healthcare decision-making. DESIGN AND PATIENTS: We identified 728 RET533 Brazilian relatives, spread out over 7 generations. We performed clinical examination, biochemical and imaging analyses in the proband and in 103 carriers. MEASUREMENT AND RESULTS: The proband has been followed without evidence of structural disease in the last 10 years but with elevated calcitonin. The clinical and surgical features of 60 thyroidectomized RET533 relatives were also described. Forty-six patients had MTC (21-72 years), and 11 patients had C-cell hyperplasia (CCH) (5-42 years). Twelve MTC patients with lymph node metastases had a tumour size of 0·7-2·8 cm. Calcitonin level and CEA were correlated with disease stage, and none of the patients presented with an altered PTH or metanephrine. A 63-year-old woman developed pheochromocytoma and breast cancer. Two other RET533 relatives developed lung squamous cell carcinoma and melanoma. CONCLUSIONS: A vast clinical variability in RET533 presentation was observed, ranging from only an elevated calcitonin level (3%) to local metastatic disease (25%). Many individuals were cured (42%) and the majority had controlled chronic disease (56%), reinforcing the need for individualized ongoing risk stratification assessment. The importance of this update relies on the fact that it allows us to delineate the natural history of RET 533 MEN2A 10 years after its first description.
Assuntos
Neoplasia Endócrina Múltipla Tipo 2a/genética , Mutação , Proteínas Proto-Oncogênicas c-ret/genética , Neoplasias da Glândula Tireoide/genética , Adolescente , Adulto , Idoso , Substituição de Aminoácidos , Calcitonina/sangue , Antígeno Carcinoembrionário/sangue , Carcinoma Neuroendócrino , Criança , Pré-Escolar , Cisteína/genética , Saúde da Família , Feminino , Seguimentos , Glicina/genética , Humanos , Masculino , Metanefrina/urina , Pessoa de Meia-Idade , Neoplasia Endócrina Múltipla Tipo 2a/cirurgia , Linhagem , Neoplasias da Glândula Tireoide/cirurgia , Tireoidectomia , Fatores de Tempo , Adulto JovemRESUMO
OBJECTIVE: Adequate isolation of nucleic acids from peripheral blood, fine-needle aspiration cells in stained slides, and fresh and formalin-fixed/paraffin-embedded tissues is crucial to ensure the success of molecular endocrinology techniques, especially when samples are stored for long periods, or when no other samples can be collected from patients who are lost to follow-up. Here, we evaluate several procedures to improve current methodologies for DNA (salting-out) and RNA isolation. MATERIALS AND METHODS: We used proteinase K treatment, heat shock, and other adaptations to increase the amount and quality of the material retrieved from the samples. RESULTS: We successfully isolated DNA and RNA from the samples described above, and this material was suitable for PCR, methylation profiling, real-time PCR and DNA sequencing. CONCLUSION: The techniques herein applied to isolate nucleic acids allowed further reliable molecular analyses. Arq Bras Endocrinol Metab. 2012;56(9):618-26.
OBJETIVO: O isolamento adequado de ácidos nucleicos a partir de sangue periférico, lâmina corada de punção aspirativa por agulha fina, tecido fixado em formalina e emblocado em parafina e tecido fresco é fundamental para assegurar o sucesso de técnicas aplicadas em endocrinologia molecular, principalmente quando lidamos com amostras estocadas por longos períodos ou quando há impossibilidade de nova coleta de amostra de pacientes que perderam o seguimento. Neste trabalho, objetivamos otimizar as metodologias clássicas para a extração de DNA (salting-out) e RNA. MATERIAIS E MÉTODOS: Utilizamos proteinase K, choque térmico, dentre outras modificações, com o objetivo de aumentar a quantidade e a qualidade do material recuperado a partir das amostras descritas acima. RESULTADOS: Isolamos com sucesso DNA e RNA de tais amostras e o material obtido foi adequado para a realização de PCR, perfil de metilação, PCR em tempo real e sequenciamento de DNA. CONCLUSÃO: As técnicas aplicadas neste estudo para isolar ácidos nucleicos permitiram a realização posterior de análises moleculares consistentes e confiáveis. Arq Bras Endocrinol Metab. 2012;56(9):618-26.
Assuntos
Humanos , DNA , RNA , Biópsia por Agulha Fina , DNA , Eletroforese em Gel de Ágar , Inclusão em Parafina , Reação em Cadeia da Polimerase , RNA , Coloração e Rotulagem , Fixação de Tecidos , Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/patologiaRESUMO
OBJECTIVE: In the last decade, data published stressed the role of highly-sensitive thyroglobulin (Tg) assays in the follow-up of differentiated thyroid carcinoma (DTC) patients. The present study describes a new, highly-sensitive Tg assay, compares it with an available commercial assay, and validates it in the follow-up of DTC patients. SUBJECTS AND METHODS: The immunofluorometric high-sensitivity Tg assay is based on monoclonal and polyclonal antibodies produced at our laboratories. It was validated in 100 samples of 87 patients with DTC submitted to total thyroidectomy, 87% of whom also received radioiodine. For correlation, all samples were also tested using a commercial Tg assay (Beckman Access) with functional sensitivity (FS) of 0.1 ng/mL. RESULTS: The new method showed FS of 0.3 ng/mL. The correlation between the two methods was good (r = 0.74; p < 0.0001). The diagnostic sensitivity was 88.9%, and it was increased to 100% when combined with neck US. CONCLUSION: This new, high-sensitivity Tg assay presented a good correlation with Beckman Access assay and with the clinical outcome of the patients. The continuous availability of a validated assay is an additional advantage for long term follow-up of DTC patients. Arq Bras Endocrinol Metab. 2012;56(9):658-65.
OBJETIVO: Na última década, estudos mostraram a importância dos ensaios de tiroglobulina (Tg) com melhor sensibilidade funcional no seguimento dos pacientes com carcinoma diferenciado de tiroide (CDT). Neste estudo, descrevemos o desenvolvimento de um novo ensaio de Tg de alta sensibilidade, que foi validado no seguimento de pacientes com CDT e correlacionado com um ensaio comercialmente disponível. SUJEITOS E MÉTODOS: O ensaio imunofluorométrico de Tg baseia-se em anticorpos, um monoclonal e um policlonal desenvolvidos em nosso laboratório. Avaliamos 100 amostras de soro de 87 pacientes com CDT submetidos à tiroidectomia total, sendo que 87% deles também receberam 131I. A Tg foi dosada também em ensaio comercial (Beckman Access). RESULTADOS: A correlação entre os dois métodos foi de 0,74 (p < 0,0001). O novo ensaio mostrou uma sensibilidade funcional de 0,3 ng/mL. A sensibilidade diagnóstica foi de 88,9%, que aumentou para 100% quando associada ao ultrassom cervical (US). CONCLUSÃO: O novo método de dosagem de Tg mostra boa correlação com o ensaio comercial Beckman Access e com a evolução clínica dos pacientes. O novo ensaio será fundamental no seguimento dos nossos pacientes com CDT. Arq Bras Endocrinol Metab. 2012;56(9):658-65.
Assuntos
Adulto , Idoso , Animais , Feminino , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Coelhos , Adulto Jovem , Fluorimunoensaio/normas , Tireoglobulina/sangue , Anticorpos Monoclonais/biossíntese , Anticorpos Monoclonais , Fluorimunoensaio/métodos , Sensibilidade e Especificidade , Neoplasias da Glândula Tireoide/diagnósticoRESUMO
BACKGROUND: There is a concern regarding the use of iodinated contrast agents (ICA) for chest and neck computed tomography (CT) to localize metastatases in patients with differentiated thyroid cancer (DTC). This is because the iodine in ICA can compete with (131)I and interfere with subsequent whole scans or radioactive iodine treatment. The required period for patients to eliminate the excess iodine is not clear. Therefore, knowing the period for iodine levels to return to baseline after the injection of ICA would permit a more reliable indication of CT for DTC patients. The most widely used marker to assess the plasmatic iodine pool is the urinary iodine (UI) concentration, which can be collected over a period of 24 hours (24U) or as a single-spot urinary sample (sU). As 24U collections are more difficult to perform, sU samples are preferable. It has not been established, however, if the measurement of iodine in sU is accurate for situations of excess iodine. METHODS: We evaluated 25 patients with DTC who received ICA to perform chest or neck CT. They collected 24U and sU urinary samples before the CT scan and 1 week and 1, 2, and 3 months after the test. UI was quantified by a semiautomated colorimetric method. RESULTS: Baseline median UI levels were 21.8 µg/dL for 24U and 26 µg/dL for sU. One week after ICA, UI median levels were very high for all patients, 800 µg/dL. One month after ICA, however, UI median levels returned to baseline in all patients, 19.0 µg/dL for 24U and 20 µg/dL for sU. Although the values of median UI obtained from sU and 24U samples were signicantly different, we observed a significant correlation between samples collected in 24U and sU in all evaluated periods. CONCLUSION: One month is required for UI to return to its baseline value after the use of ICA and for patients (after total thyroidectomy and radioiodine therapy) to eliminate the excess of iodine. In addition, sU samples, although not statistically similar to 24U values, can be used as a good marker to evaluate patients suspected of contamination with iodine.
Assuntos
Meios de Contraste , Radioisótopos do Iodo/uso terapêutico , Iodo/urina , Compostos Radiofarmacêuticos , Neoplasias da Glândula Tireoide/radioterapia , Adolescente , Adulto , Carcinoma/radioterapia , Carcinoma/cirurgia , Carcinoma Papilar , Meios de Contraste/farmacocinética , Feminino , Humanos , Iodo/farmacocinética , Compostos de Iodo/urina , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Compostos Radiofarmacêuticos/farmacocinética , Câncer Papilífero da Tireoide , Neoplasias da Glândula Tireoide/cirurgia , Tireoidectomia , Tomografia Computadorizada por Raios X , Adulto JovemRESUMO
OBJECTIVE: Adequate isolation of nucleic acids from peripheral blood, fine-needle aspiration cells in stained slides, and fresh and formalin-fixed/paraffin-embedded tissues is crucial to ensure the success of molecular endocrinology techniques, especially when samples are stored for long periods, or when no other samples can be collected from patients who are lost to follow-up. Here, we evaluate several procedures to improve current methodologies for DNA (salting-out) and RNA isolation. MATERIALS AND METHODS: We used proteinase K treatment, heat shock, and other adaptations to increase the amount and quality of the material retrieved from the samples. RESULTS: We successfully isolated DNA and RNA from the samples described above, and this material was suitable for PCR, methylation profiling, real-time PCR and DNA sequencing. CONCLUSION: The techniques herein applied to isolate nucleic acids allowed further reliable molecular analyses.
Assuntos
DNA/isolamento & purificação , RNA/isolamento & purificação , Biópsia por Agulha Fina , DNA/sangue , Eletroforese em Gel de Ágar , Humanos , Inclusão em Parafina , Reação em Cadeia da Polimerase , RNA/sangue , Coloração e Rotulagem , Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/patologia , Fixação de TecidosRESUMO
OBJECTIVE: In the last decade, data published stressed the role of highly-sensitive thyroglobulin (Tg) assays in the follow-up of differentiated thyroid carcinoma (DTC) patients. The present study describes a new, highly-sensitive Tg assay, compares it with an available commercial assay, and validates it in the follow-up of DTC patients. SUBJECTS AND METHODS: The immunofluorometric high-sensitivity Tg assay is based on monoclonal and polyclonal antibodies produced at our laboratories. It was validated in 100 samples of 87 patients with DTC submitted to total thyroidectomy, 87% of whom also received radioiodine. For correlation, all samples were also tested using a commercial Tg assay (Beckman Access) with functional sensitivity (FS) of 0.1 ng/mL. RESULTS: The new method showed FS of 0.3 ng/mL. The correlation between the two methods was good (r = 0.74; p < 0.0001). The diagnostic sensitivity was 88.9%, and it was increased to 100% when combined with neck US. CONCLUSION: This new, high-sensitivity Tg assay presented a good correlation with Beckman Access assay and with the clinical outcome of the patients. The continuous availability of a validated assay is an additional advantage for long term follow-up of DTC patients.
Assuntos
Fluorimunoensaio/normas , Tireoglobulina/sangue , Adulto , Idoso , Animais , Anticorpos Monoclonais/biossíntese , Feminino , Fluorimunoensaio/métodos , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Coelhos , Sensibilidade e Especificidade , Neoplasias da Glândula Tireoide/diagnóstico , Adulto JovemRESUMO
BACKGROUND: It has been suggested that the female preponderance for autoimmune thyroid disease might be associated with hormonal differences, abortion, and fetal microchimerism. Findings emerging from the few epidemiological studies on this matter, however, are controversial. In this study, we investigated the hypothesis whether parity, abortion, and the use of estrogens are associated with a higher risk for thyroid autoimmunity. METHODS: This cross-sectional population-based study examined 675 women from a Japanese-Brazilian population aged above 30 years. Thyroid peroxidase antibodies (TPOAbs), thyroglobulin antibodies (TgAbs), thyrotropin, and free T4 were measured by immunofluorimetric assays. Urinary iodine concentration was measured using a colorimetric method. Data were analyzed in logistical regression models to obtain the odds ratio (OR) and 95% confidence intervals. RESULTS: TPOAbs and TgAbs were present in 11.6% and 13.6% of women, respectively. After adjustment for age, smoking, and urinary iodine concentration, the OR for positive TPOAb (OR, 1.22 [95% confidence interval, 0.732.02]) and for positive TgAb (OR, 1.01 [0.631.62]) among women who had one or more parities did not differ from those who had never given birth. In addition, we found no association between the presence of thyroid antibodies and previous abortions or the use of estrogens. CONCLUSIONS: Parity, abortion, and the use of estrogens are not associated with thyroid autoimmunity in this population. These findings reinforce previous reports that advocated against a key role of fetal microchimerism in the pathogenesis of autoimmune thyroid disease.
Assuntos
Doenças Autoimunes/imunologia , Paridade/imunologia , Doenças da Glândula Tireoide/imunologia , Aborto Induzido/estatística & dados numéricos , Adulto , Povo Asiático , Brasil/epidemiologia , Estrogênios/uso terapêutico , Feminino , Humanos , Iodeto Peroxidase/imunologia , Japão/etnologia , Pessoa de Meia-Idade , Gravidez , Tireoglobulina/imunologia , Doenças da Glândula Tireoide/epidemiologia , Tireotropina/sangue , Tiroxina/sangueRESUMO
CONTEXT: Serum thyroglobulin is a sensitive tumor marker in the follow-up of patients with differentiated thyroid carcinoma (DTC), but the presence of endogenous anti-thyroglobulin antibodies (TgAb) can interfere on its measurement. To prevent interference by TgAb, several investigators have tried to quantify blood mRNA Tg by real-time RT-PCR, but the results have been variable, not reporting a correlation between mRNA Tg and the presence of metastases. OBJECTIVE: The aim of the study was to evaluate the development of a sensitive and specific quantitative RT-PCR assay for blood mRNA Tg in the follow-up of patients with DTC. DESIGN AND PATIENTS: An assay employing primers located in a region not affected by alternative splicing or single nucleotide polymorphisms was developed to study 104 DTC patients (13 of 104 with positive TgAb). RESULTS: The assay is specific for thyroid tissue because we found mRNA Tg expression in normal thyroid tissue, but we did not find any mRNA Tg expression in any extrathyroidal tissues. Quantitative mRNA Tg levels were significantly different between patients "free of disease" (82 of 104) and those with metastases (22 of 104) (2.61 +/- 0.26 vs. 27.58 +/- 1.62 pg mRNA Tg/microg RNA) (P < 0.0001). A cutoff point of 5.51 was able to discriminate between the two groups. In addition, the measurement of mRNA Tg was not affected by the presence of TgAb. CONCLUSION: This new mRNA Tg quantification is a reliable method that allowed us to differentiate patients free of disease from those with metastases, and it could represent an appropriate molecular marker for the follow-up of patients with DTC, especially those with positive TgAb.
Assuntos
RNA Mensageiro/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Tireoglobulina/biossíntese , Tireoglobulina/genética , Neoplasias da Glândula Tireoide/diagnóstico , Adolescente , Adulto , Idoso , Primers do DNA , DNA Complementar/biossíntese , DNA Complementar/genética , Feminino , Humanos , Assistência de Longa Duração , Masculino , Pessoa de Meia-Idade , Pescoço/diagnóstico por imagem , Metástase Neoplásica/diagnóstico , Recidiva Local de Neoplasia/diagnóstico , RNA Mensageiro/genética , Curva ROC , Neoplasias da Glândula Tireoide/diagnóstico por imagem , Neoplasias da Glândula Tireoide/patologia , Ultrassonografia , Adulto JovemRESUMO
AIM: The objective of this study is to assess the contribution of ADIPOQ variants to type 2 diabetes in Japanese Brazilians. METHODS: We genotyped 200 patients with diabetes mellitus (100 male and 100 female, aged 55.0 years [47.5-64.0 years]) and 200 control subjects with normal glucose tolerant (NGT) (72 male and 128 female, aged 52.0 years [43.5-64.5 years]). RESULTS: Whereas each polymorphism studied (T45G, G276T, and A349G) was not significantly associated with type 2 diabetes mellitus, the haplotype GGA was overrepresented in our diabetic population (9.3% against 3.1% in NGT individuals, P=.0003). Also, this haplotype was associated with decreased levels of adiponectin. We also identified three mutations in exon 3: I164T, R221S, and H241P, but, owing to the low frequencies of them, associations with type 2 diabetes could not be evaluated. The subjects carrying the R221S mutation had plasma adiponectin levels lower than those without the mutation (2.10 microg/ml [1.35-2.55 microg/ml] vs. 6.68 microg/ml [3.90-11.23 microg/ml], P=.015). Similarly, the I164T mutation carriers had mean plasma adiponectin levels lower than those noncarriers (3.73 microg/ml [3.10-4.35 microg/ml] vs. 6.68 microg/ml [3.90-11.23 microg/ml]), but this difference was not significant (P=.17). CONCLUSIONS: We identified in the ADIPOQ gene a risk haplotype for type 2 diabetes in the Japanese Brazilian population.
Assuntos
Adiponectina/genética , Diabetes Mellitus Tipo 2/epidemiologia , Adiponectina/sangue , Povo Asiático/genética , Glicemia/genética , Índice de Massa Corporal , Brasil/epidemiologia , Diabetes Mellitus Tipo 2/etnologia , Diabetes Mellitus Tipo 2/genética , Feminino , Estudo de Associação Genômica Ampla , Haplótipos , Humanos , Japão/etnologia , Masculino , Pessoa de Meia-Idade , Mutação , Polimorfismo GenéticoRESUMO
OBJECTIVE: The currently available data concerning the influence of subclinical thyroid disease (STD) on morbidity and mortality are conflicting. Our objective was to investigate the relationships between STD and cardiometabolic profile and cardiovascular disease at baseline, as well as with all-cause and cardiovascular mortality in a 7.5-year follow-up. DESIGN: Prospective, observational study. METHODS: An overall of 1110 Japanese-Brazilians aged above 30 years, free of thyroid disease, and not taking thyroid medication at baseline were studied. In a cross-sectional analysis, we investigated the prevalence of STD and its relationship with cardiometabolic profile and cardiovascular disease. All-cause and cardiovascular mortality rates were assessed for participants followed for up to 7.5 years. Association between STD and mortality was drawn using multivariate analysis, adjusting for potential confounders. RESULTS: A total of 913 (82.3%) participants had euthyroidism, 99 (8.7%) had subclinical hypothyroidism, and 69 (6.2%) had subclinical hyperthyroidism. At baseline, no association was found between STD and cardiometabolic profile or cardiovascular disease. Multivariate-adjusted hazard ratios (HRs (95% confidence interval)) for all-cause mortality were significantly higher for individuals with both subclinical hyperthyroidism (HR, 3.0 (1.5-5.9); n=14) and subclinical hypothyroidism (HR, 2.3 (1.2-4.4); n=13) than for euthyroid subjects. Cardiovascular mortality was significantly associated with subclinical hyperthyroidism (HR, 3.3 (1.4-7.5); n=8), but not with subclinical hypothyroidism (HR, 1.6 (0.6-4.2); n=5). CONCLUSION: In the Japanese-Brazilian population, subclinical hyperthyroidism is an independent risk factor for all-cause and cardiovascular mortality, while subclinical hypothyroidism is associated with all-cause mortality.