Ricardo Iwakura

Fluorescence lifetime of normal, benign, and malignant thyroid tissues

Abstract. Fine-needle aspiration cytology is the standard technique to diagnose thyroid pathologies. However, this method results in a high percentage of inconclusive and false negatives. The use of time-resolved fluorescence techniques to detect biochemical composition and tissue structure alterations could help to develop a portable, minimally invasive, and nondestructive method to assist during surgical procedures. This study aimed to use fluorescence lifetimes to differentiate healthy and benign tissues from malignant thyroid tissue. The thyroid tissue was excited at 298–300 nm and the fluorescence decay registered at 340 and 450 nm. We observed fluorescence lifetimes at 340 nm emission of 0.80±0.26 and 3.94±0.47  ns for healthy tissue; 0.90±0.24 and 4.05±0.46  ns for benign lesions; and 1.21±0.14 and 4.63±0.25  ns for malignant lesions. For 450 nm emissions, we obtain lifetimes of 0.25±0.18 and 3.99±0.39  ns for healthy tissue, 0.24±0.17 and 4.20±0.48  ns for benign lesions, 0.33±0.32 and 4.55±0.55  ns for malignant lesions. Employing analysis of variance, we differentiate malignant lesions from benign and healthy tissues. In addition, we use quadratic discriminant analysis to distinguish malignant from benign and healthy tissues with an accuracy of 76.1%, sensitivity of 74.7%, and specificity of 83.3%. These results indicate that time-resolved fluorescence can assist medical evaluation of thyroid pathologies during surgeries.

Hidratação e equilíbrio ácido-base em pacientes cirúrgicos

Estudou-se a influencia da hidratacao em 30 pacientes submetidos a cirurgia de pequeno e grande porte. Os pacientes foram divididos em grupos de 5 conforme o porte cirurgico e o tipo de hidratacao: restricao hidrica, segundo o balanco diario e sobrecarga hidrossalina. As alteracoes mais relevantes do equilibrio acido base foram: pre-operatorio - alcalose respiratoria; pos-operatorio imediato - acidose respiratoria; 1o, 2o e 3o dias de pos-operatorio - alcalose respiratoria, metabolica ou mista. Os metodos de hidratacao com restricao hidrica ou segundo o balanco nao afetaram o equilibrio acido-base, enquanto que a sobrecarga hidrossalina reduziu de modo significativo a incidencia de alcalose metabolica no pos-operatorio.

Proteína p53 em nefroblastomas

A imunoexpressao do antigeno p53 foi estudada em 35 pacientes com idade media de 38± 29 meses. Todos foram tratados com nefrectomia e quimioterapia, em 17 se associou tambem a radioterapia. O tempo medio de seguimento foi de 69± 66 meses. Em 5 deles a histologia era defavoravel. Em 10 casos (28,5%) a marcacao foi positiva, com ordem crescente de positividade para epitelio, blastema e estroma. Cinco pacientes faleceram da doenca, nenhum deles com histologia desfavoravel. Nao se encontrou relacao significante entre o padrao imunohistoquimico e os paremetros seguintes: sobrevida dos pacientes, estadio e grau do tumor.

Characterization of thyroid tissue using infrared spectroscopy

Financial support: None. Conflicts of interest: No conflicts of interest declared concerning the publication of this article. Submitted: July 20, 2017. Accepted: December 05, 2017. The study was carried out at Faculdade de Medicina (FM), Universidade de São Paulo (USP), Ribeirão Preto (RP), SP, Brazil. abstract Introduction: In recent years, the number of surgical procedures involving the thyroid gland has increased worldwide; however, no increase in mortality rate has been observed. The Fourier Transform Infrared (FTIR) spectroscopy technique presents evidence in the characterization of multiple tissues, such as the thyroid gland, with the advantage of being rapid and preserving the tissue analyzed. Objectives: Characterize both healthy and pathological thyroid tissues by FTIR spectroscopy. Methods: Patients were selected at the Head and Neck Surgery Service of the Hospital das Clínicas, Ribeirão Preto Medical School, University of Sao Paulo USP, Ribeirão Preto-SP, Brazil, from 2014 to 2015. The sample consisted of 44 patients with reference for thyroidectomy. The analysis was performed by defining the areas of each band using the OriginPro 8.6.0 software. The band was then normalized to 1240 cm-1. The mean area was calculated using the Student’s t-test with p<0.05. After calculation of the means, the second-order derivative of the spectrum was evaluated to show the positions of each absorption band. Results: The infrared spectrum of each piece was obtained and expressed as a function of absorbance and wave numbers in the mean IR (4000-900 cm-1). The present study demonstrated that, in the analysis of thyroid tissue by FTIR spectroscopy, it is possible to differentiate benign nodules from healthy tissue with significant difference in the area of the B-band between healthy tissue and goiter, which corresponds to 1452.90 cm-1 in healthy tissue (proteins and lipids) and 1069.80 cm-1 in goiter (DNA), as well as significant difference in width between normal thyroid tissue and carcinoma of the C band. Conclusions: FTIR spectroscopy is able to differentiate pathologically altered thyroid tissues from the thyroid gland compared with findings in healthy thyroid tissues. In patients with benign nodular disease of the thyroid gland, it is possible to differentiate healthy goiter tissue with statistical significance, as well as malignant nodules from healthy tissue through FTIR spectroscopy.

Analysis of the role of thyroidectomy and thymectomy in the surgical treatment of secondary hyperparathyroidism

PURPOSE Parathyroidectomy can be subtotal or total with an autograft for the treatment of renal hyperparathyroidism. In both cases, it may be extended with bilateral thymectomy and total or partial thyroidectomy. Thymectomy may be recommended in combination with parathyroidectomy in order to prevent mediastinal recurrence. Also, the occurrence of thyroid disease observed in patients with hyperparathyroidism is poorly understood and the incidence of cancer is controversial. The aim of the present study was to report the experience of a single center in the surgical treatment of renal hyperparathyroidism and to analyse the role of thyroid and thymus surgery in association with parathyroidectomy. MATERIALS AND METHODS We analysed parathyroid surgery data, considering patient demographics, such as age and gender, and surgical procedure data, such as type of hyperparathyroidism, associated thyroid or thymus surgery, surgical duration and mediastinal recurrence. Histopathological results of thyroid and thymus samples were also analysed. RESULTS Medical records of 109 patients who underwent parathyroidectomy for secondary hyperparathyroidism were reviewed. On average, thymectomy did not have impact on time of parathyroidectomy (p = 0.62) even when thyroidectomy was included (p = 0.91). Intrathymic parathyroids were detected in 7.5% of the thymuses removed and papillary carcinoma was detected in 20,8% of thyroid tissue samples. Two patients showed recurrence of supernumerary intrathymic parathyroids and a single case of mediastinitis was observed. CONCLUSIONS Parathyroidectomy with thymectomy and/or thyroidectomy has an important role in the treatment of renal hyperparathyroidism since thyroid cancer can frequently occur and require surgery. Thymectomy should be considered to avoid recurrence and a risky re-operation.

Time-resolved fluorescence spectroscopy for intraoperative assistance of thyroid surgery

Searching for new methods to provide information of biochemical composition and structure is critical to improve the prognosis of thyroid diseases. The use of time-resolved fluorescence techniques to detect biochemical composition and tissue structure alterations could help develop a portable, minimally invasive, and non-destructive method to assist during surgical procedures. This research looks for employ a fluorescence technique based on lifetime measurements to differentiate healthy and benign lesions from malignant thyroid tissue. We employ a wide range of excitation and chose a more appropriate region for this work: 298-300 nm; and the fluorescence decay was measured at 340-450 nm. We observed fluorescence lifetimes at 340 nm emission of 0.80±0.26 and 3.94±0.47 ns for healthy tissue; 0.90±0.24 and 4.05±0.46 ns for benign lesions; and 1.21±0.14 and 4.63±0.25 ns for malignant lesions. For 450 nm emissions, we obtain lifetimes of 0.25±0.18 and 3.99±0.39 ns for healthy tissue, 0.24±0.17 and 4.20±0.48 ns for benign lesions, 0.33±0.32 and 4.55±0.55 ns for malignant lesions. We successfully demonstrated that fluorescence lifetimes at 340 nm emission can differentiate between thyroid malignant and healthy/benign tissues.

Optical Characterization of Parathyroid Tissues

The parathyroid glands are small and often similar to lymph nodes, fat, and thyroid tissue. These glands are difficult to identify during surgery and a biopsy of the parathyroid for identification can lead to damage of the gland. The use of static and time-resolved fluorescence techniques to detect biochemical composition and tissue structure alterations could help to develop a portable, minimally invasive, and nondestructive method to assist medical evaluation of parathyroid tissues. In this study, we investigated 10 human parathyroid samples using absorbance, fluorescence, excitation, and time-resolved fluorescence measurements. Moreover, we compared the results of time-resolved fluorescence measurements with 59 samples of thyroid tissues. The fluorescence lifetimes with emission at 340 nm were 1.09 ± 0.10 and 4.46 ± 0.06 ns for healthy tissue, 1.01 ± 0.25 and 4.39 ± 0.36 ns for benign lesions, and 0.67 ± 0.36 and 3.92 ± 0.72 ns for malignant lesions. The lifetimes for benign and malignant lesions were significantly different, as attested by the analysis of variance with confidence levels higher than 87%. For each class of samples (healthy, benign, and malignant) we perceived statistical differences between the thyroid and parathyroid tissue, independently. After further investigations, fluorescence methods could become a tool to identify normal and pathological parathyroid tissues and distinguish thyroid from parathyroid tissues.

Antígeno MIB-1 em nefroblastomas

Foram estudados 35 pacientes tratados com nefrectomia radical e quimioterapia, em 17 (48,5%) dos quais se associou tambem a radioterapia. A idade media dos pacientes foi de 38± 29 meses e o tempo de seguimento pos-operatorio de 69± 66 meses. Obito pela neoplasia ocorreu em 5 pacientes, todos com histologia favoravel. As pecas conservadas em formol ou blocos de parafina para imunhistoquimica com anticorpo MIB-1, metodo da avidina-biotina-peroxidase. Em 13/35 (37,1%) dos tumores a marcacao para o MIB-1 foi positiva. As proporcoes respectivas de marcacao para blastema, epitelio e estroma foram: 34,6%, 18,7% e 0%. Nao houve diferenca estatistica entre a marcacao imunohistoquimica e com o tipo histologico, estadio e sobrevida dos pacientes.