Biomedical subjects

Edward Limbert

Publications and source records attributed to Edward Limbert.

9 recordsLinked to original sources

PubMed2006

[Diagnosis and treatment of solitary thyroid nodule--study and evaluation in Portugal].

INTRODUCTION: The best diagnostic and treatment strategy for an approach to the nodular thyroid disease continues to be a controversial issue. OBJECTIVES: The aim of this study was to characterise medical practice in the diagnosis and treatment of nodular thyroid disease by endocrinologists and surgeons in Portugal in 2002. METHODS: A questionnaire based on that used by the European Thyroid Association and the American Thyroid Association was drawn up. The questionnaire, based on a well-defined index case, was circulated by the Portuguese Endocrinology Society to endocrinologists and surgeons: 42 year-old woman with solitary thyroid nodule measuring 2 x 3 cm, with no history of malfunction or painful symptoms. Each doctor was asked to reply as to the adopted diagnosis and therapy procedures for the index case. Eleven variations to the original case were proposed in order to evaluate the alterations for each variation. RESULTS: 1492 questionnaires were sent out, 163 to endocrinologists and 1329 to surgeons. A total of 104 were returned. The global response rate was 7%. The response rate for endocrinologists was 27% and 4.5% for surgeons. Of the 104 questionnaires returned, 42% were from endocrinologists and 58% from surgeons. Concerning tests prescribed, surgeons would use more tests than endocrinologists for the index case. The main differences in laboratory terms were the higher number of prescriptions for total T4 and T3 and thyroglobulin by surgeons and more prescriptions for AATPO by endocrinologists. The average number of tests was 4.6, 4.1 for endocrinologists and 5.1 for surgeons. Relative to imaging and cytology, 32% of doctors advocated a scintigraphy to diagnose the index case, with no significant differences between endocrinologists and surgeons. Ultrasonography was used by over 85% of respondents. 90% prescribed a cytology, 83% guided by palpation and 18% ultrasonography-guided. Concerning treatment, 33% of doctors advocated levothyroxin treatment; surgery was advocated by 16.3% of endocrinologists and 36.6% of surgeons. Meanwhile, the majority of doctors (68%) would opt for no treatment and simply maintain the patient under surveillance. CONCLUSIONS: There are important differences in the approach to nodular thyroid disease among the various doctors and specialists, which highlight the difficulty in achieving a diagnostic and therapeutic consensus.

Endocrinology↗

PubMed2006

PROP1 gene analysis in Portuguese patients with combined pituitary hormone deficiency.

OBJECTIVE: Mutations of the PROP1 gene lead to combined pituitary hormone deficiency (CPHD), which is characterized by a deficiency of GH, TSH, LH/FSH, PRL and, less frequently, ACTH. This study was undertaken to investigate the molecular defect in a cohort of patients with CPHD. DESIGN, PATIENTS AND MEASUREMENTS: A multicentric study involving 46 cases of CPHD (17 familial cases belonging to seven kindreds and 29 sporadic cases) selected on the basis of clinical and hormonal evidence of GH deficiency, central hypothyroidism and hypogonadotrophic hypogonadism, in the absence of an identified cause of hypopituitarism. Mutations of PROP1 were investigated by DNA sequencing. Clinical, hormonal and neuroradiological data were collected at each centre. RESULTS: PROP1 mutations were identified in all familial cases: five kindreds presented a c. 301-302delAG mutation, one kindred presented a c. 358C --> T (R120C) mutation and one presented a previously unreported initiation codon mutation, c. 2T --> C. Of the 29 sporadic cases, only two (6.9%) presented PROP1 germline mutations (c. 301-302delAG, in both). Phenotypic variability was observed among patients with the same mutations, particularly the presence and age of onset of hypocortisolism, the levels of PRL and the results of pituitary imaging. One patient presented a sellar mass that persisted into adulthood. CONCLUSIONS: This is the first report of a mutation in the initiation codon of the PROP1 gene and this further expands the spectrum of known mutations responsible for CPHD. The low mutation frequency observed in sporadic cases may be due to the involvement of other unidentified acquired or genetic causes.

Adolescent↗

PubMed2005

[Treatment and follow up protocol in differentiated thyroid carcinomas of follicular origin].

Differentiated thyroid carcinoma of follicular origin (DTCFO), although not very frequent, has registered a raising incidence in the last decades. In the majority of the cases, DTCFO is a curable disease when treated and monitored by experienced, multidisciplinary teams. These factors contribute to an increasing number of DTCFO survivors requiring life-long monitoring, due to the possibility of occurrence of recurrences many years after the initial treatment. Several aspects of the treatment and management of these patients are still controversial. The present protocol represents the consensus of the members of the Grupo de Estudo da Tiróide of the Sociedade Portuguesa de Endocrinologia, Diabetes e Metabolismo. It aims to define guidelines, in agreement with the current state of the art and contemplating the necessary adaptations to local constrains, that ensure decreased mortality and protection of patients' quality of life, avoiding unnecessarily aggressive or ineffective treatments, optimizing the use of the available resources.

Clinical Protocols↗

PubMed2005

Metastatic follicular carcinoma associated with hyperthyroidism.

PURPOSE: A 68-year-old man with metastatic follicular thyroid carcinoma had T3 hyperthyroidism. MATERIAL AND METHODS: A bone scan showed intense uptake in the thyroid and multiple areas of increased uptake in the skeleton. Hyperthyroidism persisted after total thyroidectomy. Treatment with I-131 induced a transient state of euthyroidism lasting approximately 9 months. Further tumor growth and relapse of hyperthyroidism eventually occurred and the patient died 25 months after surgery. Molecular and cytogenetic analyses were performed. RESULTS: No mutations were detected of either of the thyrotropin receptor or of the alpha subunit of the stimulatory guanine-nucleotide-binding proteins. Hyperthyroidism was unlikely the result of thyroid-stimulating receptor antibodies. Comparative genomic hybridization analysis showed that the tumor was characterized by multiple chromosomal imbalances. CONCLUSIONS: This is an unusual case of follicular thyroid carcinoma with initial high I-131 uptake by the thyroid and bone metastases and concurrent hyperthyroidism. Despite the increased I-131 uptake in the tumor, I-131 treatment only transiently controlled the hyperthyroidism and had no effect on tumor size. The cause of hyperthyroidism remained unknown. T3 predominance was unlikely the result of type 2 deiodinase overexpression because loss of genetic material was demonstrated at chromosome 14 long arm, where type 2 deiodinase is mapped.

Adenocarcinoma, Follicular↗

PubMed2005

Association of polymorphisms in ERCC2 gene with non-familial thyroid cancer risk.

The ERCC2 protein is an evolutionary conserved ATP-dependent helicase that is associated with a TFIIH transcription factor complex and plays an important role in nucleotide excision repair. Mutations in this gene are responsible for xeroderma pigmentosum and also for Cocayne syndrome and trichothiodystrophy. Several single nucleotide polymorphisms have been identified in the ERCC2 locus. Among them, a G23591A polymorphism in the codon 312 results in an Asp --> Asn substitution in a conserved region and a A35931C polymorphism in the codon 751 results in a Lys --> Gln substitution. Because these polymorphisms have been associated with an increased risk for several types of cancers, we carried out an hospital based case-control study in a Caucasian Portuguese population to evaluate the potential role of these polymorphisms on the individual susceptibility to thyroid cancer. The results obtained did not reveal a significant association between each individual polymorphism studied (G23591A and A35931C) and an increased thyroid cancer risk, but individuals homozygous for non-wild-type variants are overrepresented in patients group. The evaluation of the different haplotypes generated by these polymorphisms showed that individuals simultaneously homozygous for rare variants of both polymorphisms have an increased risk for thyroid cancer [adjusted odds ratio (OR) 3.084; 95% confidence interval (95% CI), 1.347-7.061; P = 0.008] and for papillary thyroid-type tumors (adjusted OR, 2.997; 95% CI, 1.235-7.272; P = 0.015) but not for follicular thyroid-type tumors. These results suggest that genetic polymorphisms in this gene might be associated with individual susceptibility towards thyroid cancer, mainly papillary-type tumors, but larger studies are required to confirm these results.

Adult↗

PubMed2004

Combined effects of glutathione S-transferase polymorphisms and thyroid cancer risk.

Since exposure to ionizing radiation, a risk factor for thyroid cancer, may produce genotoxins potentially eliminated by glutathione-S-transferases, we conducted a case control study to evaluate the role of the GSTM1- and GSTT1-null genotypes and GSTP1 polymorphisms in thyroid cancer. The frequency of GSTP1 Ile/Ile, GSTM1-, and GSTT1-null genotypes was increased in cancer patients when compared with control population. Considering the genotypes over-represented in thyroid cancer patients as potential risk genotypes, we carried out an odds ratio (OR) analysis considering the presence of none, one, two, or three risk genotypes. The results obtained showed that the presence of three potentially risk alleles (GSTM1 null, GSTT1 null, and GSTP1 Ile/Ile) lead to a significant OR increase for all the cases, irrespective of the type of tumor (OR=2.91), for papillary (OR=3.64) but not for follicular tumors. The presence of GSTP1 Ile/Ile leads to a significant later age of tumor onset when compared with GSTP1 Ile/Val and Val/Val (P<0.05), suggesting a possible association between GSTP1 Ile/Ile and the age of disease manifestation. These results suggest that combined GST polymorphisms lead to a moderate increased risk for thyroid cancer, especially for the papillary type, and GSTP1 polymorphisms might modulate the age of onset of the disease.

Adult↗

PubMed2004

Follow-up and management of differentiated thyroid carcinoma: a European perspective in clinical practice.

As differentiated (follicular and papillary) thyroid cancer (DTC) may recur years after initial treatment, follow-up of patients with DTC is long term. However, this population has changed, with more individuals being discovered at an earlier stage of disease, so that previous follow-up protocols based mostly on data from high-risk patients no longer apply. We have proposed, in a previous issue of this Journal, an improved protocol for the follow-up of low-risk patients with DTC based on the findings of recent studies. We report here the case of a paradigmatic patient with papillary thyroid carcinoma, with the goal of illustrating the benefits of applying this algorithm in routine clinical practice. We also offer expanded and additional comments on various issues in the management of DTC.

Adult↗

PubMed2002

Possible transient adaptive response to mitomycin C in peripheral lymphocytes from thyroid cancer patients after iodine-131 therapy.

Our study attempted to assess the possible induction and persistence of an adaptive response in lymphocytes of thyroidectomized thyroid cancer patients treated with 131I (2,590 MBq, corresponding to whole body doses in the range of 200-300 mGy), to a testing dose of mitomycin C (MMC) in vitro. The cytogenetic endpoint studied was the induction of micronuclei in cytokinesis-blocked peripheral blood lymphocytes, immediately before treatment and 1, 6 and 24 months after therapy. One month after therapy, induction of micronucleated cytokinesis-blocked lymphocytes ( per thousand ) by MMC was lower (34.6 +/- 7.7) than before therapy (52.1 +/- 5.0). In 7 of 11 patients this reduction was significant. However, at 6 months, induction of micronuclei was markedly higher (133.1 +/- 13.6). This significant increase was observed regardless of the decrease at 1 month. At 24 months, the frequency of micronucleated cells decreased (84.8 +/- 5.5), but remained higher than before treatment. The results obtained 1 month after therapy could reflect adaptation due to radiation, or a higher rate of early apoptosis or cell death, with bone marrow suppression, visible as a lower response in vitro towards MMC. At 6 months, recovery of the lymphocyte population may occur, and higher responses to MMC in vitro could reflect higher chromosomal instability in the previously irradiated stem cells with a concomitant disappearance of adaptation, whereas at 24 months the results show a tendency to return to pretherapy values.

Adaptation, Physiological↗

PubMedDate not supplied

[Thyroid diseases].

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Female↗