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N J Sarlis

Publications and source records attributed to N J Sarlis.

At least 19 recordsLinked to original sources
PubMed2002

Resistance to thyroid hormone in a patient without thyroid hormone receptor mutations.

Resistance to thyroid hormone (RTH) is a clinical syndrome characterized by elevated serum thyroid hormone (TH) levels, unsuppressed thyrotropin (TSH) levels, and tissue hyposensitivity to TH. In almost all cases, the genetic basis of RTH lies in mutation of one of the two TH receptor beta (TRbeta) alleles. Recently, patients from several families with phenotypic manifestations of RTH in the absence of TR mutations have been described. We report a case of a 31-year-old woman who presented with goiter, tachycardia, elevated TH levels, unsuppressed TSH, and "inappropriately normal" levels of peripheral TH action markers. In two separate clinical evaluations, the patient exhibited typical clinical and biochemical evidence for peripheral and pituitary RTH. Surprisingly, reverse transcriptase-polymerase chain reaction (RT-PCR) of full-length TRalpha and TRbeta mRNAs, and genomic PCR using primers flanking exons encoding the carboxy-terminal region of TRbeta failed to demonstrate mutations in the TRalpha or TRbeta genes. It is likely that defects in the regulation of TR genes or mutations in transcriptional cofactors involved in TR signaling account for this patient's phenotype.

Adult↗
PubMed2001

A case of spurious hypercalcitoninemia: a cautionary tale on the use of plasma calcitonin assays in the screening of patients with thyroid nodules for neoplasia.

The measurement of plasma CT has an important role as a screening test for medullary thyroid carcinoma (MTC) in patients with thyroid nodules. However, elevated plasma CT levels should be interpreted within the context of the overall clinical picture in each individual case and carefully validated before therapeutic decisions are made. We present the case of a 17-yr-old girl who was referred to us with a thyroid nodule and elevated plasma CT levels, as measured by a one-site RIA not involving prior plasma extraction. Plasma CT was re-measured using two different methods, a RIA with prior plasma extraction and a two-site immunochemiluminometric assay (ICMA), and was either very low or undetectable. Subsequently, samples were re-assayed using the initially applied CT RIA; plasma CT levels were again found to be elevated. These elevations were of a spurious nature, probably caused by the presence of an unidentified substance in the patient's plasma interfering with the measurement of CT in the initially used RIA. Our patient was eventually diagnosed with Hashimoto's thyroiditis, and had no evidence of MTC. As several conditions can cause either true or spurious hypercalcitoninemia, we suggest that elevated plasma CT levels should be confirmed at least once before other extensive diagnostic investigations are initiated or thyroidectomy is recommended. Finally, the assay selected should detect only the mature CT molecule.

Adolescent↗
PubMed2001

The spectrum of thyroid diseases in childhood and its evolution during transition to adulthood: natural history, diagnosis, differential diagnosis and management.

In this contribution, we review current knowledge on the pathogenesis, diagnosis and differential diagnosis of thyroid disorders in childhood and adolescence, as well as present an update on therapy methods and management guidelines for these disorders. This overview is conceptually divided into two parts, one focusing on thyroid functional disorders, i.e. conditions leading to hyper- and hypothyroidism, and another one pertinent to structural abnormalities of the thyroid gland, i.e. nodular disorders and thyroid cancer. Currently, congenital hypothyroidism is diagnosed in a much more timely fashion rather than in the past, rendering hypothyroidism-related mental retardation and developmental deficits very rare in newborns and children and, hence, diminishing significantly its public health impact. At the same time, considerable advances have occurred in our understanding of the molecular basis of several genetic conditions affecting the thyroid gland in childhood, such as familial non-autoimmune hyperthyroidism, as well as of the pathways leading to thyroid neoplasia.

Adolescent↗
PubMed2001

Renal metastases from thyroid papillary carcinoma: study of sodium iodide symporter expression.

Kidney metastases from thyroid cancer are rare. We report two such patients and demonstrate that the in vivo 131I uptake by the kidney metastasis is associated with high levels of sodium iodide (Na+/I-) symporter (NIS) expression in the first case. Case 1: A 61-year-old woman with papillary thyroid carcinoma-follicular variant (PTC-FV) presented with scapular metastasis. After thyroidectomy and scapulectomy, a 131I posttherapy scan showed left upper quadrant uptake. A 3.0-cm metastatic PTC-FV deposit was removed by partial nephrectomy. Case 2: A 53-year-old woman presented with back pain. A computed tomography (CT) scan showed a 3.5-cm renal mass, a multinodular goiter, and lung metastases thought secondary to a renal cell carcinoma. A unilateral nephrectomy revealed metastatic PTC-FV. After thyroidectomy, a 131I posttherapy scan showed lung and skeletal metastases. NIS immunoreactivity in tumoral tissue was strongly positive in the primary tumor, shoulder, and kidney metastasis in case 1, as well as in the primary tumor in case 2. Spotty, low-level NIS expression was observed in the kidney metastasis in case 2. In conclusion, kidney metastases of PTC-FV may occasionally retain adequate levels of NIS expression, enabling their detection during life. Thus, intense uptake in the abdomen during 131I imaging should not be assumed to be physiological gastrointestinal tract residual radionuclide activity.

Carcinoma, Papillary↗
PubMed2001

Somatic mutation of TRbeta can cause a defect in negative regulation of TSH in a TSH-secreting pituitary tumor.

In patients with TSH-secreting tumors (TSHomas), serum TSH is poorly suppressed by thyroid hormone. The mechanism for this defect in negative regulation of TSH secretion is not known. To investigate the possibility of a somatic mutation of TR causing this defect, we performed mutational analysis of TRbeta by RT-PCR using RNA obtained from five surgically resected TSHomas. In one TSHoma, we identified a somatic mutation in the ligand-binding domain of TRbeta that caused a His to Tyr substitution at codon 435 of TRbeta1 corresponding to codon 450 of TRbeta2. Interestingly, this mutation occurred in the same codon as two mutations (TRbetaH435L and H435Q) previously identified in patients with the syndrome of resistance to thyroid hormone. This mutant TRbeta had impaired T3 binding and T3-mediated negative regulation. It also blocked the negative regulation by wild-type TRbeta2 on glycoprotein hormone alpha-subunit and TSHbeta reporter genes in cotransfection studies. Our results demonstrate that somatic mutation of TRbeta occurred in a TSHoma and was probably responsible for the defect in negative regulation of TSH by thyroid hormone in the tumor.

Adult↗
PubMed2001

Low concentrations of the histone deacetylase inhibitor, depsipeptide (FR901228), increase expression of the Na(+)/I(-) symporter and iodine accumulation in poorly differentiated thyroid carcinoma cells.

Thyroid carcinoma accounts for the majority of deaths from endocrine cancers. A major cause of treatment failure is the inability to trap iodine. Chemotherapeutic agents with differentiating properties have been tried in an attempt to increase iodine uptake. We examined the ability of the novel histone deacetylase (HDAC) inhibitor, depsipeptide (FR901228), to modulate the expression of thyroid-specific genes. Four cell lines, two derived from follicular thyroid carcinomas (FTC 133 and FTC 236) and two derived from anaplastic thyroid carcinomas (SW-1736 and KAT-4) were used. In these four cell lines, a very low concentration of depsipeptide (1 ng/mL) increased histone acetylation and expression of both thyroglobulin and the Na(+)/I(-) symporter messenger RNAs. After 3 days, messenger RNA levels approached those of a normal thyroid control. Depsipeptide induced increases in (125)I accumulation indicated that a functional Na(+)/I(-) symporter protein was induced. Transient transfections indicate that the effects are mediated at least in part by a trans-activating factor. These in vitro results suggest that depsipeptide or other histone deacetylase inhibitors might be used clinically in thyroid carcinomas that are unable to trap iodine as an adjunct to radioiodine therapy.

Acetylation↗
PubMed2001

Aberrant alternative splicing of thyroid hormone receptor in a TSH-secreting pituitary tumor is a mechanism for hormone resistance.

Patients with TSH-secreting pituitary tumors (TSHomas) have high serum TSH levels despite elevated thyroid hormone levels. The mechanism for this defect in the negative regulation of TSH secretion is not known. We performed RT-PCR to detect mutations in TRbeta from a surgically resected TSHoma. Analyses of the RT-PCR products revealed a 135-bp deletion within the sixth exon that encodes the ligand-binding domain of TRbeta2. This deletion was caused by alternative splicing of TRbeta2 mRNA, as near-consensus splice sequences were found at the junction site and no deletion or mutations were detected in the tumoral genomic DNA. This TRbeta variant (TRbeta2spl) lacked thyroid hormone binding and had impaired T3-dependent negative regulation of both TSHbeta and glycoprotein hormone alpha-subunit genes in cotransfection studies. Furthermore, TRbeta2spl showed dominant negative activity against the wild-type TRbeta2. These findings strongly suggest that aberrant alternative splicing of TRbeta2 mRNA generated an abnormal TR protein that accounted for the defective negative regulation of TSH in the TSHoma. This is the first example of aberrant alternative splicing of a nuclear hormone receptor causing hormonal dysregulation. This novel posttranscriptional mechanism for generating abnormal receptors may occur in other hormone-resistant states or tumors in which no receptor mutation is detected in genomic DNA.

Adenoma↗
PubMed2001

Exaggerated levothyroxine malabsorption due to calcium carbonate supplementation in gastrointestinal disorders.

OBJECTIVE: To describe a patient with primary hypothyroidism in whom ingestion of levothyroxine with calcium carbonate led to markedly elevated serum thyrotropin concentrations. CASE SUMMARY: A 61-year-old white woman with primary hypothyroidism, systemic lupus erythematosus, celiac disease, and history of Whipple resection for pancreatic cancer was euthyroid with levothyroxine 175-188 micrograms/d. After taking a high dose of calcium carbonate (1250 mg three times daily) with levothyroxine, she developed biochemical evidence of hypothyroidism (thyrotropin up to 41.4 mU/L) while remaining clinically euthyroid. Delaying calcium carbonate administration by four hours returned her serum thyrotropin to a borderline high concentration (5.7 mU/L) within a month. Serum concentrations of unbound and total thyroxine and triiodothyronine tended to decrease, but remained borderline low to normal while the patient concomitantly received levothyroxine and calcium carbonate. DISCUSSION: Concomitant administration of levothyroxine and calcium carbonate often results in levothyroxine malabsorption. While in most patients the clinical consequences of this interaction, even with prolonged exposure, are relatively small, overt hypothyrodism may develop in patients with preexisting malabsorption disorders. However, as the current case illustrates, the clinical manifestations of the initial levothyroxine deficit may not always be apparent and, of all usual laboratory thyroid function tests, only thyrotropin measurement will reliably uncover the exaggerated levothyroxine malabsorption. CONCLUSIONS: Decreased absorption of levothyroxine when given with calcium carbonate may be particularly pronounced in patients with preexisting malabsorption disorders. Once recognized, a change in drug administration schedule usually minimizes or eliminates this interaction.

Antacids↗
PubMed2000

Evidence for a common step in three different processes for modulating the kinetic properties of glucocorticoid receptor-induced gene transcription.

The dose-response curve of steroid hormones and the associated EC(50) value are critical parameters both in the development of new pharmacologically active compounds and in the endocrine therapy of various disease states. We have recently described three different variables that can reposition the dose-response curve of agonist-bound glucocorticoid receptors (GRs): a 21-base pair sequence of the rat tyrosine aminotransferase gene called a glucocorticoid modulatory element (GME), GR concentration, and coactivator concentration. At the same time, each of these three components was found to influence the partial agonist activity of antiglucocorticoids. In an effort to determine whether these three processes proceed via independent pathways or a common intermediate, we have examined several mechanistic details. The effects of increasing concentrations of both GR and the coactivator TIF2 are found to be saturable. Furthermore, saturating levels of either GR or TIF2 inhibit the ability of each protein, and the GME, to affect further changes in the dose-response curve or partial agonist activity of antisteroids. This competitive inhibition suggests that all three modulators proceed through a common step involving a titratable factor. Support for this hypothesis comes from the observation that a fragment of the coactivator TIF2 retaining intrinsic transactivation activity is a dominant negative inhibitor of each component (GME, GR, and coactivator). This inhibition was not due to nonspecific effects on the general transcription machinery as the VP16 transactivation domain was inactive. The viral protein E1A also prevented the action of each of the three components in a manner that was independent of E1A's ability to block the histone acetyltransferase activity of CBP. Collectively, these results suggest that three different inputs (GME, GR, and coactivator) for perturbing the dose-response curve, and partial agonist activity, of GR-steroid complexes act by converging at a single step that involves a limiting factor prior to transcription initiation.

Acetyltransferases↗
PubMed2000

Increased levothyroxine requirements presenting as "inappropriate" TSH secretion syndrome in a patient with nephrotic syndrome.

Patients with primary thyroid failure on levothyroxine (LT4) replacement who develop nephrotic syndrome (NS) may rarely present with an increase in LT4 requirements. In this report, we describe a patient with thyroid failure following radioactive iodine ablation for Graves' disease who required an escalation of LT4 doses following the onset of NS. The case presented with disproportionately elevated TSH levels in the presence of normal (or slightly subnormal) thyroid hormone levels, thus, masquerading as a state of "inappropriate" TSH secretion. This pattern of extreme dysregulation in thyroid function indices due to urinary loss of thyroid hormones has not been previously described in NS, and, therefore, extends the spectrum of endocrine manifestations of NS.

Adult↗
PubMed2000

Diurnal thyrotropin secretion in short-term profound primary hypothyroidism: does it ever persist?

Circulating serum thyrotropin (TSH) levels in euthyroid humans show a definite circadian variation, which is maintained in both mild hyperthyroidism and mild hypothyroidism. Yet conflicting data exist with regard to whether this variation persists in at least some patients with severe primary hypothyroidism. We, therefore, studied the diurnal variation in serum TSH in 10 patients (age range 20 to 84 years) with a history of thyroid failure due to prior total thyroidectomy and radioiodine (RAI) ablative treatment performed for thyroid cancer after short-term discontinuation of thyroid hormone (TH) therapy. Serum TSH was measured hourly for a 24-hour period. All data were normalized by converting the TSH values to a percentage (%), designating the 11:00 hour value as 100% (baseline). The average serum TSH levels were markedly elevated in all patients. There was no statistically significant difference between the TSH % values at any time during the 24-hour period when compared with baseline. Further, cosine regression analysis showed absence of rhythmicity in TSH % values over time; notably, no patient showed a variation in TSH % values > or = 15% of baseline. In conclusion, diurnal rhythmicity in serum TSH levels was abolished in a uniform cohort of patients with short-term severe primary hypothyroidism. We speculate that the complete lack of peripheral negative feedback input to the hypothalamus or pituitary or both may override the central rhythm-sustaining influences on TSH secretion.

Adult↗
PubMed2000

Ectopic lingual thyroid: an otolaryngologic emergency beyond childhood.

Ectopic thyroid is rare and occasionally presents suddenly in childhood. Adult patients with thyroid ectopy who develop local symptoms commonly have an enlarged ectopic gland and hypothyroidism. We describe the first case of an adult patient who sudden presented with sudden dysphagia and dyspnea caused by a large lingual thyroid in clinical and biochemical euthyroidism. Treatment consisted of surgical removal of the ectopic gland and thyroid hormone replacement therapy.

Adolescent↗
PubMed2000

Assessing the effects of thyroid suppression on benign solitary thyroid nodules. A model for using quantitative research synthesis.

Systematic review of the available information with a modified, largely quantitative method of research synthesis disclosed that an initial trial of thyroid hormone suppression therapy leads to clinically significant (> or = 50%) reduction of nodule size or arrest of nodule growth in a subset of patients with benign solitary thyroid nodules. In fact, in addition to objective improvements due to decreasing nodule size, L-T4 suppression therapy may benefit patients by reducing perinodular thyroid volume. Consequently, both pressure symptoms and cosmetic complaints may improve (9, 68). Additional studies for the assessment of the risks versus benefits of supraphysiologic doses of L-T4, the optimal level of thyroid suppression and the dose needed to achieve this magnitude of reduction, the optimal length of the initial trial, and the conditions for the continuation of L-T4 thyroid suppression therapy, as well as the identification of markers for patients most likely to respond to this therapy, are warranted. Finally, quantitative assessment of available evidence as described here may be applicable to the review of other controversial issues as well.

Adult↗
PubMed2000

Recombinant human thyrotropin for the diagnosis and treatment of a highly functional metastatic struma ovarii.

The optimal treatment of metastatic thyroid cancer that produces high amounts of thyroid hormone has not been well defined. A 46-yr-old woman presented with a follicular thyroid carcinoma arising from a struma ovarii with hepatic metastases. After the removal of both the struma and the thyroid gland, the liver metastases showed evidence of a high degree of hormonogenesis. Brain, chest, abdomen, and bone imaging was negative for additional metastases. Because iodine uptake by most thyroid carcinomas is quite low in the absence of high levels of ambient TSH, we used recombinant human TSH (rhTSH) (Thyrogen) to achieve a concentration of 131I activity in the tumor high enough for a significant cytotoxic effect. After rhTSH administration (0.9 mg im daily for 2 consecutive days), a 131I diagnostic whole body scan confirmed the existence of 17 discrete hepatic foci of 131I uptake. To calculate the amount of 131I that would deliver an absorbed radiation dose that would be optimally cytotoxic to the metastases (>8000 rad/lesion) and not to the normal liver, we performed lesion dosimetry. Analysis of dosimetric data showed that 15 of 17 lesions would receive an adequate radiation dose following the administration of 65 mCi of 131I. Additionally, we performed whole body dosimetry to assure that this dose would not cause bone marrow toxicity. The patient was reevaluated 6 months after therapy; the liver metastases showed significant, but partial, response. In conclusion, we used the combination of rhTSH with lesional and whole body dosimetry for the treatment of highly functional metastases from follicular thyroid carcinoma arising within a struma ovarii. This strategy can be applied to determine a safe and effective dose of 131I for the treatment of any thyroid cancer metastases that produce enough TH to preclude stimulation of endogenous pituitary TSH secretion.

Female↗