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Orientador: Sergio de Toledo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-08T11:35:58Z (GMT). No. of bitstreams: 1 Feitosa_DanieladaSilva_M.pdf: 3070475 bytes, checksum: 8b886a0cc7e91cdb336051a875f764c3 (MD5) Previous issue date: 2007 / Resumo: O objetivo do presente estudo foi avaliar, histometricamente, a influência de vdisfunções tireoidianas, hiper e hipotireoidismo, sobre o reparo ósseo ao redor de implantes de titânio inseridos em tíbias de ratos. Foram utilizados 42 ratos Wistar machos aleatoriamente divididos em 3 grupos experimentais: grupo 1 (n=15) -hipertireoidismo (800 mcg de L-tiroxina sódica e 180 mcg de triiodotironina sódica / 1000 ml de água); grupo 2 (n=14) - controle; grupo 3 (n=13) ¿ hipotireoidismo (1000 mg de propiltiouracil / 1000ml de água). Após 98 dias da administração das soluções, a constatação das alterações dos níveis hormonais foi obtida por meio de análise sérica e os implantes foram colocados em uma tíbia por animal. O reparo foi avaliado sessenta dias após o procedimento cirúrgico. Os ratos foram sacrificados e obtidas secções não-descalcificadas. Os parâmetros histométricos, avaliados separadamente na região cortical (zona A) e medular (zona B), foram: porcentagem de osso numa região de 500mm adjacente ao implante (AO), porcentagem de preenchimento ósseo dentro das roscas (PR) e porcentagem de contato direto osso-implante (CD). Os dados coletados foram analisados estatisticamente utilizando a análise de variância ANOVA monofatorial e o teste Tukey (a=5%). Na zona A, observou-se redução do reparo ósseo com a diminuição dos níveis de T3 e T4. Houve redução significante em AO no grupo 3 (93,74±2,70) em relação ao grupo 2 (95,93±1,90). Para PR, os valores foram 78,72±3,88 no grupo 1, 71,92±5,12 no grupo 2 e 65,60±8,76 no grupo 3, estatisticamente diferentes entre si. Para CD, diferença significante foi observada entre os grupos 1 e 3, apresentando respectivamente, 20,76±9,3 e 12,28±9,04. No osso medular, não houve diferenças estatisticamente significantes entre os grupos em nenhum dos parâmetros avaliados. Portanto, dentro dos limites deste estudo, as disfunções tireoidianas, hiper e hipoireoidismo, influenciaram o reparo do osso cortical ao redor de implantes de titânio inseridos em tíbias de ratos / Abstract: The aim of this study was to evaluate, by histometric analysis, the influence of thyroid dysfunctions, hyper and hypothyroidism, on bone healing around titanium implants inserted in rats. Forty-two male Wistar rats were randomly assigned to one of three groups: group 1 (n=15) - hyperthyroidism (800 mcg of sodium Lthyroxine and 180 mcg of sodium triiodothyronine / 1000 ml of water); group 2 (n=14) - control; group 3 (n=13) - hypothyroidism (1000 mg propyllthiouracil / 1000ml of water). Ninety eight days after solutions administration, serum analyses confirmed hormone levels differences and single screw-shaped titanium implants were placed in rat tibiae. Bone healing was evaluated sixty days after surgical procedure. The animals were sacrificed and undecalcified sections from tibiaes with implants were obtained. Percentage of bone in a 500mm-wide zone lateral to the implant (BA), percentage of bone filling within the limits of the implant threads (BF) and percentage of bone-to-implant contact (BIC) were obtained and arranged separately for the cortical (Zone A) and cancellous bone (Zone B). The data were statistically analysed using one-way ANOVA and Tukey¿s test (alpha=5%). In Zone A, intergroup analyses revealed a tendency for reduction in bone repair while hormone levels decreased. There was a statistical reduction in BA in group 3 (93.74±2.70) compared to group 2 (95.93±1.90). T3 and T4 significantly affected BF, showing 78.72±3.88, 71.92±5.12 and 65.60±8.76, for groups 1, 2 e 3, respectively. Differences were also found in BIC, between groups 1(20.76±9.3) and 3 (12.28±9.04). In addition, no differences were observed with respect to Zone B, in any parameter. Therefore, within the limits of the present investigation, thyroid dysfunctions may influence cortical bone repair around titanium implants placed in rats / Mestrado / Periodontia / Mestre em Clínica Odontológica

Endocrine disrupting compounds are ubiquitous in aquatic environments. Exposure to these compounds may cause deiodination of thyroid hormones in fish and also affect certain behaviors. Behavioral change may be a useful indicator of deiodination on an organismal level, and may indicate effects to populations, especially if these behaviors affect reproduction. We exposed Pimephales promelas (Fathead Minnow) to effluent from a recently upgraded wastewater treatment facility. The effluent contained a matrix of low-level (< 1.0 µg/L) concentrations of endocrine disrupting compounds pre- and post-upgrade. We examined the behavior of adult Fathead Minnow exposed to treated wastewater for 90 days and the behavior of their offspring at 12-20 days old. There was no significant difference in 11 of the 12 behaviors we documented for adult fish in control and treatment tanks (p > 0.05). However, treatment fish were significantly more aggressive towards a decoy fish compared to control fish (p < 0.05). There was no significant difference found in the predator avoidance behaviors examined in the F1 generation. Although our results did not find any significant differences between control and treatment fish in regard to most behaviors we would typical associate with thyroid deiodination, such behaviors may have manifested following a longer exposure period or by having a larger sample size. Other future considerations should include looking at different behaviors (e.g. social behaviors) and further characterization of the finished effluent.

Dominant-activating mutations in the RET (rear-ranged during transfection) proto-oncogene, which encodes a receptor tyrosine kinase, is often associated with the development of medullary thyroid carcinoma (MTC). The proximal promoter region of the RET gene consists of a guanine-rich sequence containing five runs of three consecutive guanine residues that serve as the binding site for transcriptional factors. As we have recently shown, this stretch of nucleotides in the promoter region is highly dynamic in nature and tend to form non-B DNA secondary structures called G-quadruplexes, which suppress the transcription of the RET gene. In the present study, ellipticine and its derivatives were identified as excellent RET G-quadruplex stabilizing agents. Circular dichroism (CD) spectroscopic studies revealed that the incorporation of a piperidine ring in an ellipticine derivative, NSC311153 improves its binding with the G-quadruplex structure and the stability induced by this compound is more potent than ellipticine. Furthermore, this compound also interfered with the transcriptional mechanism of the RET gene in an MTC derived cell line, TT cells and significantly decreased the endogenous RET protein expression. We demonstrated the specificity of NSC311153 by using papillary thyroid carcinoma (PTC) cells, the TPC1 cell line which lacks the G-quadruplex forming sequence in the promoter region due to chromosomal rearrangement. The RET downregulation selectively suppresses cell proliferation by inhibiting the intracellular Raf/MEK/ERK and PI3K/Akt/mTOR signaling pathways in the TT cells. In the present study, we also showed that the systemic administration of a water soluble NSC311153 analog in a mouse MTC xenograft model inhibited the tumor growth through RET downregulation.

Toxicities of sulfur-based drugs have been attributed to formation of highly reactive sulfur oxo-acids and depletion of glutathione by the formation of reactive metabolites. Metabolic activation of these sulfur centers to conceivably toxic reactive metabolites (RMs) that can covalently modify proteins is considered the initial step in drug-induced toxicity. Despite considerable effort and research, detection and characterization of these RMs during drug development and therapy remains a challenge. Methimazole (MMI) and 6-propyl-2-thiouracil (PTU) are two commonly used antithyroid, sulfur-based drugs. Though effective, these drugs are associated with idiosyncratic toxicity. PTU has acquired a black box warning and physicians are calling for its withdrawal. RMs resulting from bioactivation of these drugs have been implicated in the aforementioned adverse reactions. Unfortunately, isolating and detecting RMs using traditional analytical techniques has not been successful due to their high reactivity and short life span, typically less than a minute. Current approaches in drug metabolism studies use microsomal incubations to generate RMs, which are then trapped using nucleophiles. Antithyroid drugs, however, are known to deactivate enzymes involved in their oxidation. Moreover, due to the complex nature of biological matrices and low abundance of possible toxic conjugates, this technique results in poor selectivity and sensitivity. This study developed and optimized an analytical method based on coupling electrochemical redox reactions and mass spectrometry to generate, detect and identify RMs from antithyroid drugs. The metabolites were also compared to those that were generated using chemical oxidants and biological microsomes. Mimicry of enzymatic oxidation of the antithyroid drugs was carried out by electrochemically oxidizing them using a coulometric cell coupled on-line to electrospray ionization mass spectrometry (EC/ESI-MS). Oxidation of MMI and subsequent trapping with nucleophile resulted in formation of adducts with N-acetylcysteine, revealing reactive metabolites. The most-postulated metabolite, sulfenic acid, had never been isolated or detected until now, using electrochemistry on-line with electrospray ionization. The results showed that bioactivation of MMI proceeds predominantly through the S-oxide and not through formation of thiyl radicals. These same trapping experiments were also conducted with PTU, but no conjugates were detected. The lack of conjugates from PTU does not preclude formation of RMs, but asserts radical pathway might be dominant in EC oxidation. A double mixing stopped flow was used to investigate the kinetics and mechanism of reaction of the MMI and the biologically relevant hypochlorous acid (HOCl), a product of oxidation of chloride (Cl-) ions by myeloperoxidase. The products from the chemical oxidations were compared to the electrochemically generated metabolites, some differences were apparent. Human liver microsomes (HLM) were also used, to investigate oxidation of PTU. Oxidation of PTU, resulted in the supposedly toxic S-oxide, but this has never been isolated, save for speculation. A comparison of metabolites that were found with HLM to those generated electrochemically showed some degree of similarity. These results show that in vitro techniques such as chemical oxidations and electrochemistry coupled to mass spectrometry can be used to mimic oxidative metabolism and subsequent high throughput screening of reactive metabolites.

Background: Radiotherapy is used in the treatment of over 50% of cancer patients and bar surgery, is the most effective cancer intervention. However, in the clinic secondary malignancies have been observed following radiotherapy and in vitro increased cell migration and invasion have been seen following radiation. The Src/FAK signalling pathway is known to play an important role in the metastatic phenotype through its involvement in cell adhesion, migration and invasion and we have previously demonstrated that radiotherapy can activate this pathway along with the phosphoinositide 3-kinase (PI3K) pathway, also associated with tumour metastases and an aggressive phenotype. Using pharmacological inhibitors, we have investigated combination approaches to evaluate whether Src and PI3K targeting is beneficial in a radiotherapy context, especially focusing on metastatic phenotype. We wished to relate pathway activation to cellular phenotype and increase understanding of the metastatic cascade, the processes involved and the signalling pathways taking the lead. Method: Using thyroid carcinoma cell lines FTC133 and 8505c the effects of Src inhibition using AZD0530, FAK inhibition using FAKi and PI3K inhibition using GDC-0941 were studied. The effects of radiotherapy alone, and in combination with the above inhibitors, were also studied. In vitro MTT, apoptosis and clonogenic assays were used to assess cell proliferation and cell survival and scratch assays, cell adhesion and cell spreading assays were used to assess the effects of the drugs on metastatic characteristics. In vivo tumour growth, survival and ex vivo clonogenics were used to measure the effects of AZD0530 and GDC-0941. Western blotting, immunofluorescence and immunohistochemistry was used to observe the effects on pathway activation and protein localisation. Results: Src and FAK inhibition reduced metastatic characteristics of thyroid carcinoma cell lines in vitro such as cell spreading and migration. FAK inhibition showed a greater effect on cell survival by MTT, clonogenic and apoptosis. In the thyroid carcinoma cell lines radiotherapy enhanced the metastatic phenotype. This was seen by enhanced activation of the Src and PI3K pathways, increased migration and invasion in vitro and enhanced tumour metastasis in vivo. By combining Src inhibition with radiation a reduction in metastatic characteristics was observed and by combining PI3K inhibition with radiotherapy radiosensitivity could be improved. With the triple combination of Src and PI3K inhibition with radiotherapy a significant reduction in cell survival was demonstrated in vitro compared to radiation alone and either inhibitor combined with radiation, with a corresponding significant reduction in tumour growth being observed in vivo. With the combination of Src and PI3K inhibition significant reductions in metastatic characteristics were also observed both in vitro and in vivo seen by a reduction in cell migration and tumour metastasis. Finally combined inhibition of the Src and PI3K pathway reduced the radiation enhanced activation of several pathways in vivo including Src and PI3K.Conclusions: Together these results suggest that the Src and PI3K pathways play a role in radiation enhanced metastatic characteristics in thyroid carcinoma and through combined inhibition of the pathway the negative effects of radiation, enhanced migration and invasion, can be inhibited and the cells can be made more radiosensitive. Full characterisation of the pathways involved in radiation induced motility and radioresistance will provide further rationale for combination therapies and provide potential for application of these therapies in the clinic.

Xenopus Laevis has provided, during the last ten years, the basis of a growing body of physiological enquiries initiated by Jolly's research on reflex action. Its viability in the laboratory and amenability to operative procedure in particular, make it a peculiarly suitable object for investigation. It is regrettable therefore, that existing literature on the anatomy of Xenopus has been directed to elucidating those characteristics which are of especial interest to the Systematists and Morphologists rather than detailed information of a type which is essential to operative procedure. There is in particular no extant account of the endocrine system of Xenopus, although it is evident from superficial inspection that the suprarenal complex differs from that of the more familar Anura. The present enquiry concerns the Thyroid Gland, Pituitary and Epiphyseal Complexes with some observations concerning the possible occurrence of chromophil cells in the kidney of Xenopus laevis. The data have been placed on record specifically and constitution of these organs in physiological operations.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Aims: To determine the association between the thyroid hormones(FT3, FT4 and TSH) and the lipid profile markers(HDL-c, LDL-c and triglycerides) values in middle-aged women with no metabolic disorders and recurrent chronic symptomatology. Materials and Methods: We carried out an analytical cross-sectional study in euthyroid women with recurrent chronic symptoms of at least six months with no apparent diagnosis who attended the endocrinological gynaecology outpatient service of a private clinic in Lima-Peru during 2012–2014. Participants who met the eligibility criteria were evaluated according to their thyroid hormones(FT3, FT4 and TSH) and lipid profile markers(HDL-c, LDL-c and triglycerides) values. We elaborated univariate/multivariate linear regression models to evaluate the association between the thyroid markers and the lipid profile levels. The reported association measure was the beta coefficient(β) with its respective p-value. Results: We analyzed 211 participants, the average age was 44.9 ± 14.0(SD) years, the FT3 and FT4 mean levels were 3.2 ± 0.4 pg/mL and 1.2 ± 0.2 ng/dL respectively, while the TSH median was 2.8(IQR:1.9–4.0) μU/mL. The mean or median levels of LDL-c, HDL-c and triglycerides were of 137.5 ± 37.9 mg/dL, 54.0 ± 15.0 mg/dL and 118.5(IQR:79.5–169.5) mg/dL respectively. In the multivariate linear regression model between the FT3 and LDL-c levels, we found that for each increase in a FT3 unit, the LDL-c values decreased on average 30.85 mg/dL(p < 0.01). We found no statistically significant associations in the other multivariate models of linear regression, among the other thyroid hormones and lipid markers. Conclusion: We found an inverse association between the FT3 and LDL-c values in women with chronic gynaecological symptoms / Revisión por pares / Revisión por pares

Ectopic thyroid gland is a developmental anomaly that results from the arrest of thyroid tissue along its path of descent from the floor of mouth to the pre tracheal position in the lower neck. It is typically found along the thyroglossal duct with the base of the tongue being the most common site. Apart from mediastinal extension of goiter, the incidence of true intrathoracic ectopic thyroid tissue is rare. Presence of ectopic thyroid has been reported not only in the chest but also in the abdomen and pelvis. Pericardial and intracardiac locations are extremely uncommon and right ventricle location is predominant among the described cases. We describe a case of incidentally detected ectopic thyroid tissue in a rarer location—adjacent to the left atrium. The patient, who had undergone a nephrectomy for renal oncocytoma 5 years ago, presented with unintentional weight loss and left sided flank pain, prompting a workup to rule out abdominal malignancy. Findings on the computed tomography (CT) scan of the abdomen and pelvis prompted further investigation including a chest CT which showed a heterogeneously enhancing mass near the left atrium. Given its location, further radiological investigations played an important role in eliminating the differential diagnosis of paraganglioma. The mass was surgically resected and discovered to be a hyperplastic thyroid nodule on histologic examination.