Placental model as an important tool to study maternal-fetal interface

The placenta is a temporary organ that plays critical roles at the maternal-fetal interface. Normal development and function of the placenta is dependent on hormonal signaling pathways that make the placenta a target of endocrine disrupting chemical (EDC) action. Studies showing association between prenatal exposure, hormone disruption, and reproductive damage indicate that EDCs are developmentally toxic and can impact future generations. In this context, new placental models (trophoblast-derived cell lines, organotypic or 3D cell models, and physiologically based kinetic models) have been developed in order to create new approach methodology (NAM) to assess and even prevent such disastrous toxic harm in future generations. With the widespread discouragement of conducting animal studies, it has become irrefutable to develop in vitro models that can serve as a substitute for in vivo models. The goal of this review is to discuss the newest in vitro models to understand the maternal-fetal interface and predict placental development, physiology, and dysfunction generated by failures in molecular hormone control mechanisms, which, consequently, may change epigenetic programming to increase susceptibility to metabolic and other disorders in the offspring. We summarize the latest placental models for developmental toxicology studies, focusing mainly on three-dimensional (3D) culture models.

Triiodothyronine (T3) upregulates the expression of proto-oncogene TGFA independent of MAPK/ERK pathway activation in the human breast adenocarcinoma cell line, MCF7

OBJECTIVE

To verify the physiological action of triiodothyronine T3 on the expression of transforming growth factor α (TGFA) mRNA in MCF7 cells by inhibition of RNA Polymerase II and the MAPK/ERK pathway.

MATERIALS AND METHODS

The cell line was treated with T3 at a physiological dose (10-9M) for 10 minutes, 1 and 4 hour (h) in the presence or absence of the inhibitors, α-amanitin (RNA polymerase II inhibitor) and PD98059 (MAPK/ERK pathway inhibitor). TGFA mRNA expression was analyzed by RT-PCR. For data analysis, we used ANOVA, complemented with the Tukey test and Student t-test, with a minimum significance of 5%.

RESULTS

T3 increases the expression of TGFA mRNA in MCF7 cells in 4 h of treatment. Inhibition of RNA polymerase II modulates the effect of T3 treatment on the expression of TGFA in MCF7 cells. Activation of the MAPK/ERK pathway is not required for T3 to affect the expression of TGFA mRNA.

CONCLUSION

Treatment with a physiological concentration of T3 after RNA polymerase II inhibition altered the expression of TGFA. Inhibition of the MAPK/ERK pathway after T3 treatment does not interfere with the TGFA gene expression in a breast adenocarcinoma cell line.

Genotype and phenotype landscape of MEN2 in 554 medullary thyroid cancer patients: the BrasMEN study

Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant genetic disease caused by RET gene germline mutations that is characterized by medullary thyroid carcinoma (MTC) associated with other endocrine tumors. Several reports have demonstrated that the RET mutation profile may vary according to the geographical area. In this study, we collected clinical and molecular data from 554 patients with surgically confirmed MTC from 176 families with MEN2 in 18 different Brazilian centers to compare the type and prevalence of RET mutations with those from other countries. The most frequent mutations, classified by the number of families affected, occur in codon 634, exon 11 (76 families), followed by codon 918, exon 16 (34 families: 26 with M918T and 8 with M918V) and codon 804, exon 14 (22 families: 15 with V804M and 7 with V804L). When compared with other major published series from Europe, there are several similarities and some differences. While the mutations in codons C618, C620, C630, E768 and S891 present a similar prevalence, some mutations have a lower prevalence in Brazil, and others are found mainly in Brazil (G533C and M918V). These results reflect the singular proportion of European, Amerindian and African ancestries in the Brazilian mosaic genome.

Cell viability assessed in a reproducible model of human osteoblasts derived from human adipose-derived stem cells

Human adipose tissue-derived stem cells (hASCs) have been subjected to extensive investigation because of their self-renewal properties and potential to restore damaged tissues. In the literature, there are several protocols for differentiating hASCs into osteoblasts, but there is no report on the control of cell viability during this process. In this study, we used osteoblasts derived from hASCs of patients undergoing abdominoplasty. The cells were observed at the beginning and end of bone matrix formation, and the expression of proteins involved in this process, including alkaline phosphatase and osteocalcin, was assessed. RANKL, Osterix, Runx2, Collagen3A1, Osteopontin and BSP expression levels were analyzed using real-time PCR, in addition to a quantitative assessment of protein levels of the markers CD45, CD105, STRO-1, and Nanog, using immunofluorescence. Rhodamine (Rho123), cytochrome-c, caspase-3, P-27, cyclin D1, and autophagy cell markers were analyzed by flow cytometry to demonstrate potential cellular activity and the absence of apoptotic and tumor cell processes before and after cell differentiation. The formation of bone matrix, along with calcium nodules, was observed after 16 days of osteoinduction. The gene expression levels of RANKL, Osterix, Runx2, Collagen3A1, Osteopontin, BSP and alkaline phosphatase activity were also elevated after 16 days of osteoinduction, whereas the level of osteocalcin was higher after 21 days of osteoinduction. Our data also showed that the cells had a high mitochondrial membrane potential and a low expression of apoptotic and tumor markers, both before and after differentiation. Cells were viable after the different phases of differentiation. This proposed methodology, using markers to evaluate cell viability, is therefore successful in assessing different phases of stem cell isolation and differentiation.

Thyroxine increases Serca2 and Ryr2 gene expression in heart failure rats with euthyroid sick syndrome

OBJECTIVE

The current study was aimed at analyzing sarcoplasmic reticulum Ca2+ ATPase (Serca2) and ryanodine receptor type 2 (Ryr2) gene expression in rats subjected to surgery that induced HF and were subsequently treated with T4 using physiological doses.

MATERIALS AND METHODS

HF was induced in 18 male Wistar rats by clipping the ascending thoracic aorta to generate aortic stenosis (HFS group), while the control group (9-sham) underwent thoracotomy. After 21 weeks, the HFS group was subdivided into two subgroups. One group (9 Wistar rats) with HF received 1.0 µg of T4/100 g of body weight for five consecutive days (HFS/T4); the other group (9 Wistar rats) received isotonic saline solution (HFS/S). The animals were sacrificed after this treatment and examined for signs of HF. Samples from the left ventricles of these animals were analyzed by RT-qPCR for the expression of Serca2 and Ryr2 genes.

RESULTS

Rats with HF developed euthyroid sick syndrome (ESS) and treatment with T4 restored the T3 values to the Sham level and increased Serca2 and Ryr2 gene expression, thereby demonstrating a possible benefit of T4 treatment for heart function in ESS associated with HF.

CONCLUSION

The T4 treatment can potentially normalize the levels of T3 as well elevated Serca2 and Ryr2 gene expression in the myocardium in heart failure rats with euthyroid sick syndrome.

Frequency of multiple endocrine neoplasia type 1 in a group of patients with pituitary adenoma: genetic study and familial screening

The purpose of this study it was to evaluate the frequency of Multiple Endocrine Neoplasia type 1 (MEN1) in patients with pituitary adenoma and to perform genetic analysis and familial screening of those individuals afflicted with MEN1. 144 patients with pituitary adenoma at Botucatu Medical School, UNESP-Univ Estadual Paulista, were assessed retrospectively for MEN1 during the years of 2005-2011. The patients were evaluated for the presence of primary hyperparathyroidism (PHP) and enteropancreatic tumors. Genetic analysis was performed for the individuals with clinically diagnosed MEN1. Thirteen patients met the diagnostic criteria for MEN1, but three individuals belong to the same family and they were considered as a single MEN1 event, revealing 7.7 % frequency of MEN1 in this patient group. Genetic analysis showed MEN1 mutations in four index cases: IVS4+1 G>A, IVS3-6 C>T, c.1547insC and a new D180A mutation. One patient did not agree to participate in the genetic study and another one was referred for follow up in other hospital. Only polymorphisms were found in the other individuals, one of which was novel. We identified a high frequency of MEN1 in pituitary adenoma patients. Since PHP is one of the most common MEN1 tumor and patients are mostly asymptomatic, we suggest that all pituitary adenoma patients have their calcium profile analyzed.

Oncogenic osteomalacia: loss of hypophosphatemia might be the key to avoid misdiagnosis

Diagnosing oncogenic osteomalacia is still a challenge. The disorder is characterized by osteomalacia caused by renal phosphate wasting and low serum concentration of 1,25-dihydroxyvitamin D3 occurring in the presence of a tumor that produces high levels of fibroblast growth factor 23. However, it is possible that the disease is much more misdiagnosed than rare. We present the case of a 42-year-old man with a long-term history of undiagnosed progressive muscle weakness. His laboratory results mainly showed low serum phosphate. Surgical removal of a nasal hemangiopericytoma that had been diagnosed five years earlier, brought him to a symptom-free condition. Even though knowing the underlying etiology would explain his osteomalacia, the patient sought medical help from countless physicians for five consecutive years, and only after adequate treatment a rewarding outcome was achieved.

Supraphysiological triiodothyronine doses diminish leptin and adiponectin gene expression, but do not alter resistin expression in calorie restricted obese rats

Thyroid hormones regulate energy balance and act on adipokines. However, while it is unclear what the effects are of calorie restriction and high doses of triiodothyronine (T(3)) on adipokines in obesity, thyroid hormones are illicitly administered in isolation or in association with a hypocaloric diet as an obesity treatment. The present study determined the effect of T(3) on serum concentrations and gene expression of the adipokines leptin, resistin, and adiponectin in calorie-restricted obese rats. Male Wistar rats received a hypercaloric diet for 20 weeks followed by calorie restriction for 8 weeks. The animals were then randomly divided into 3 groups: calorie restriction (OR), OR with 5 μg of T(3)/100 g BW (RS1), and OR with 25 μg of T(3)/100 g BW (RS2) for 2 weeks. Blood and adipose tissue samples were collected for biochemical, hormonal, and gene expression analyses. Serum concentrations of leptin (OR: 3.7±0.6, RS1: 3.8±1, RS2 0.2±0.07 ng/dl) and resistin (OR: 2.5±0.6, RS1: 2.5±0.5, RS2 1.6±0.3 ng/dl) were diminished at the higher dose, while serum adiponectin (OR: 31±7, RS1: 24±5, RS2 26±7 ng/dl) levels were lower in the low dose group. Administration of T(3) reduced leptin gene expression (OR: 0.91±0.1, RS1: 0.95±0.1, RS2 0.22±0.1) only at the higher dose, resistin expression (OR: 1.06±0.2, RS1: 1.04±0.1, RS2 0.88±0.2) was not influenced by T(3) treatment, and adiponectin expression (OR: 1.55±0.5, RS1: 0.95±0.15, RS2 0.97±0.13) was diminished independent of the T(3) dose. These results indicate that T(3), directly or indirectly, inhibits the expression of leptin and adiponectin in calorie restricted obese animals.

Relationship between work rate and oxygen uptake in mitochondrial myopathy during ramp-incremental exercise

We determined the response characteristics and functional correlates of the dynamic relationship between the rate (Δ) of oxygen consumption (VO(2)) and the applied power output (work rate = WR) during ramp-incremental exercise in patients with mitochondrial myopathy (MM). Fourteen patients (7 males, age 35.4 ± 10.8 years) with biopsy-proven MM and 10 sedentary controls (6 males, age 29.0 ± 7.8 years) took a ramp-incremental cycle ergometer test for the determination of the VO(2) on-exercise mean response time (MRT) and the gas exchange threshold (GET). The ΔVO(2)/ΔWR slope was calculated up to GET (S(1)), above GET (S(2)) and over the entire linear portion of the response (S(T)). Knee muscle endurance was measured by isokinetic dynamometry. As expected, peak VO(2) and muscle performance were lower in patients than controls (P < 0.05). Patients had significantly lower ΔVO(2)/ΔWR than controls, especially the S(2) component (6.8 ± 1.5 vs 10.3 ± 0.6 mL·min(-1)·W(-1), respectively; P < 0.001). There were significant relationships between ΔVO(2)/ΔWR (S(T)) and muscle endurance, MRT-VO(2), GET and peak VO(2) in MM patients (P < 0.05). In fact, all patients with ΔVO(2)/ΔWR below 8 mL·min(-1)·W(-1) had severely reduced peak VO(2) values (<60% predicted). Moreover, patients with higher cardiopulmonary stresses during exercise (e.g., higher Δ ventilation/carbon dioxide output and Δ heart rate/ΔVO(2)) had lower ΔVO(2)/ΔWR (P < 0.05). In conclusion, a readily available, effort-independent index of aerobic dysfunction during dynamic exercise (ΔVO(2)/ΔWR) is typically reduced in patients with MM, being related to increased functional impairment and higher cardiopulmonary stress.

Molecular analysis of the PROP1 and HESX1 genes in patients with septo-optic dysplasia and/or pituitary hormone deficiency

OBJECTIVE: The present study aimed at evaluating the PROP1 and HESX1 genes in a group of patients with septo-optic dysplasia (SOD) and pituitary hormone deficiency (combined - CPHD; isolated GH deficiency - GHD). Eleven patients with a clinical and biochemical presentation consistent with CPHD, GHD or SOD were evaluated. SUBJECTS AND METHODS: In all patients, the HESX1 gene was analyzed by direct sequence analysis and in cases of CPHD the PROP1 gene was also sequenced. RESULTS: A polymorphism (1772 A > G; N125S) was identified in a patient with SOD. We found three patients carrying the allelic variants 27 T > C; A9A and 59 A > G; N20S in exon 1 of the PROP1 gene. Mutations in the PROP1 and HESX1 genes were not identified in these patients with sporadic GHD, CPHD and SOD. CONCLUSION: Genetic alterations in one or several other genes, or non-genetic mechanisms, must be implicated in the pathogenic process.

Misclassification probability as obese or lean in hypercaloric and normocaloric diet

The aim of the present study was to determine the classification error probabilities, as lean or obese, in hypercaloric diet-induced obesity, which depends on the variable used to characterize animal obesity. In addition, the misclassification probabilities in animals submitted to normocaloric diet were also evaluated. Male Wistar rats were randomly distributed into two groups: normal diet (ND; n=31; 3.5 Kcal/g) and hypercaloric diet (HD; n=31; 4.6 Kcal/g). The ND group received commercial Labina rat feed and HD animals a cycle of five hypercaloric diets for a 14-week period. The variables analysed were body weight, body composition, body weight to length ratio, Lee Index, body mass Index and misclassification probability. A 5% significance level was used. The hypercaloric pellet-diet cycle promoted increase of body weight, carcass fat, body weight to length ratio and Lee Index. The total misclassification probabilities ranged from 19.21% to 40.91%. In conclusion, the results of this experiment show that misclassification probabilities occur when dietary manipulation is used to promote obesity in animals. This misjudgement ranges from 19.49% to 40.52% in hypercaloric diet and 18.94% to 41.30% in normocaloric diet.

Molecular analysis of the Von Hippel-Lindau (VHL) gene in a family with non-syndromic pheochromocytoma: the importance of genetic testing

The two index patients of the family analyzed in this study had undergone bilateral adrenalectomy for pheochromocytomas. This prompted genetic analyses of the probands and seven first-degree relatives. The two pheochromocytoma patients and two additional asymptomatic family members were found to harbor a mutation c496G>T in exon 3 of the VHL gene. The family was then lost to systematic follow-up. Three years after performing the initial genetic evaluation, the sister of the probands, who was known to carry the same VHL germline mutation, was referred to our service after a pregnancy that was complicated by preeclampsia. She reported paroxysms suggestive for pheochromocytoma, but her urinary metanephrines were negative. However, computerized tomography of the abdomen showed an adrenal mass that was also positive on metaiodobenzylguanidine (MIBG) scintigraphy. This study illustrates that molecular analysis of the index patient(s) can lead to the identification of presymptomatic relatives carrying the mutation. Moreover, despite negative urinary metanephrines, the identification of a specific mutation has led to an increased suspicion and detection of a pheochromocytoma in the sister of the probands.

Tamoxifen inhibits transforming growth factor-alpha gene expression in human breast carcinoma samples treated with triiodothyronine

OBJECTIVES

To examine the effects of triiodothyronine (T3), 17beta-estradiol (E2), and tamoxifen (TAM) on transforming growth factor (TGF)-alpha gene expression in primary breast cancer cell cultures and interactions between the different treatments.

METHODS AND RESULTS

Patients included in the study (no.=12) had been newly diagnosed with breast cancer. Fresh human breast carcinoma tissue was cut into 0.3- mm slices. These slices were placed in six 35-mm dishes on 2-ml organ culture medium. Dishes received the following treatments: dish 1: ethanol; dish 2: T3; dish 3: T3+TAM; dish 4: TAM; dish 5: E2; dish 6: E2+TAM. TGF-alpha mRNA content was normalized to glyceraldehyde-3-phosphate dehydrogenase mRNA levels. All tissues included in this study were positive for estrogen receptor (ER) and thyroid hormone receptor expression. Treatment with T3 for 48 h significantly increased TGF-alpha mRNA levels compared to controls (15-fold), and concomitant treatment with TAM reduced expression to 3.4-fold compared to controls. When only TAM was added to the culture medium, TGF-alpha mRNA expression increased 5.3-fold, significantly higher than with all other treatment modalities.

CONCLUSION

We demonstrate that TGF-alpha mRNA expression is more efficiently upregulated by T3 than E2. Concomitant treatment with TAM had a mitigating effect on the T3 effect, while E2 induced TGF-alpha upregulation. Our findings show some similarities between primary culture and breast cancer cell lines, but also some important differences: a) induction of TGF-alpha, a mitogenic protein, by TAM; b) a differential effect of TAM that may depend on relative expression of ER alpha and beta; and c) supraphysiological doses of T3 may induce mitogenic signals in breast cancer tissue under conditions of low circulating E2.

Possible association between Carney complex and multiple endocrine neoplasia type 1 phenotypes

Carney Complex (CNC) and Multiple Endocrine Neoplasia type 1 (MEN1) are forms of multiple endocrine neoplasia of dominant autosomal inheritance. Diagnosis of CNC occurs when two major criteria (lentiginoses, primary pigmented nodular adrenocortical disease, cardiac and cutaneous myxomas, acromegaly, testicular neoplasias, thyroid cancer) are observed and/or a major criterion associated with a supplementary criterion (affected relative, PRKAR1A gene mutation) occurs. On the other hand, diagnosis for MEN1 occurs through detection of two or more tumors located at the pituitary gland, parathyroid and/or pancreatic cells. The present case describes a 55 year-old male patient, diagnosed with acromegaly, primary hyperparathyroidism and papillary thyroid cancer, exhibiting components that meet the diagnostic criteria of both conditions described. Despite the occurrence of only one sporadic association or the acromegaly per se being responsible for the papillary cancer, new molecular mechanisms may not be ruled out.

A Hypercaloric pellet-diet cycle induces obesity and co-morbidities in wistar rats

The present study was carried to develop and analyze the consequences of hypercaloric pellet-diet cycle that promotes obesity in rats. Male Wistar rats were randomly distributed into two groups that received either normal diet (ND; n =32; 3,5 Kcal/g) or a hypercaloric diet (HD; n =32; 4,6 Kcal/g). The ND group received commercial Labina rat feeding while the HD animals received a cycle of five hypercaloric diets over a 14-week period. The effects of the diets were analyzed in terms of body weight, body composition, hormone-metabolite levels, systolic arterial pressure and glucose tolerance at the 5% significance level. The hypercaloric pellet diet cycle promoted an increase in body weight and fat, systolic arterial pressure and a high serum level of glucose, triacylglycerol, insulin and leptin. The HD group also presented an impaired glucose tolerance. In conclusion, the results of this study show that the hypercaloric pellet-diet cycle promoted obesity in Wistar rats and displayed several characteristics that are commonly associated with human obesity, such as high arterial pressure, insulin resistance, hyperglycaemia, hyperinsulinaemia, hyperleptinaemia and dyslipidaemia.

Down-regulation of the cardiac sarcoplasmic reticulum ryanodine channel in severely food-restricted rats

We have shown that myocardial dysfunction induced by food restriction is related to calcium handling. Although cardiac function is depressed in food-restricted animals, there is limited information about the molecular mechanisms that lead to this abnormality. The present study evaluated the effects of food restriction on calcium cycling, focusing on sarcoplasmic Ca2+-ATPase (SERCA2), phospholamban (PLB), and ryanodine channel (RYR2) mRNA expressions in rat myocardium. Male Wistar-Kyoto rats, 60 days old, were submitted to ad libitum feeding (control rats) or 50% diet restriction for 90 days. The levels of left ventricle SERCA2, PLB, and RYR2 were measured using semi-quantitative RT-PCR. Body and ventricular weights were reduced in 50% food-restricted animals. RYR2 mRNA was significantly decreased in the left ventricle of the food-restricted group (control = 5.92 +/- 0.48 vs food-restricted group = 4.84 +/- 0.33, P < 0.01). The levels of SERCA2 and PLB mRNA were similar between groups (control = 8.38 +/- 0.44 vs food-restricted group = 7.96 +/- 0.45, and control = 1.52 +/- 0.06 vs food-restricted group = 1.53 +/- 0.10, respectively). Down-regulation of RYR2 mRNA expressions suggests that chronic food restriction promotes abnormalities in sarcoplasmic reticulum Ca2+ release.

Câncer diferenciado da tiróide de baixo risco: revisão do estado atual da literatura e proposta de conduta

A incidência do câncer diferenciado da tiróide vem aumentando há várias décadas no Brasil, assim como em todo o mundo. A popularização de métodos diagnósticos sensíveis e de uso relativamente simples tem contribuído para o diagnóstico cada vez mais freqüente de carcinomas de pequeno tamanho. Uma parte destes tumores ocorre em pacientes denominados de baixo risco, que poderiam se beneficiar de estratégias de conduta menos agressivas. Entretanto, a definição de baixo risco ainda é confusa e não existem meios seguros para distinguir os pacientes que evoluirão de forma pior dos demais. Por outro lado, o uso de novos métodos de acompanhamento vem mudando a maneira de conduzir estes casos. Um grupo multidisciplinar que inclui pesquisadores básicos, endocrinologistas, médicos nucleares, cirurgiões e patologistas endócrinos reviu a literatura pertinente e, com base em sua experiência, propõe algumas normas de conduta no carcinoma diferenciado da tiróide chamado de baixo risco em nosso meio.

Profile of thyroid hormones in breast cancer patients

Estrogen involvement in breast cancer has been established; however, the association between breast cancer and thyroid diseases is controversial. Estrogen-like effects of thyroid hormone on breast cancer cell growth in culture have been reported. The objective of the present study was to determine the profile of thyroid hormones in breast cancer patients. Serum aliquots from 26 patients with breast cancer ranging in age from 30 to 85 years and age-matched normal controls (N = 22) were analyzed for free triiodothyronine (T3F), free thyroxine (T4F), thyroid-stimulating hormone (TSH), antiperoxidase antibody (TPO), and estradiol (E2). Estrogen receptor ss (ERss) was determined in tumor tissues by immunohistochemistry. Thyroid disease incidence was higher in patients than in controls (58 vs 18%, P < 0.05). Subclinical hyperthyroidism was the most frequent disorder in patients (31%); hypothyroidism (8%) and positive anti-TPO antibodies (19%) were also found. Subclinical hypothyroidism was the only dysfunction (18%) found in controls. Hyperthyroidism was associated with postmenopausal patients, as shown by significantly higher mean T3 and T4 values and lower TSH levels in this group of breast cancer patients than in controls. The majority of positive ERss tumors were clustered in the postmenopausal patients and all cases presenting subclinical hyperthyroidism in this subgroup concomitantly exhibited Erss-positive tumors. Subclinical hyperthyroidism was present in only one of 6 premenopausal patients. We show here that postmenopausal breast cancer patients have a significantly increased thyroid hormone/E2 ratio (P < 0.05), suggesting a possible tumor growth-promoting effect caused by this misbalance.

Low triiodothyronine (T3) or reverse triiodothyronine (rT3) syndrome modifies gene expression in rats with congestive heart failure

Heart failure (HF) is frequently associated with euthyroid "sick" syndrome (low T3 and elevated rT3). We investigated if altered thyroid hormone in HF could affect expression of the TH receptor (TRalpha1), and alpha and beta myosin heavy chains (alpha-MHC, beta-MHC). HF was provoked in rats by aortic stenosis. We showed that rT3 generated from liver and kidney deiodination significantly increased and T3 decreased in HF; there was significantly higher TRalpha1 expression, no alpha-MHC expression, but beta-MHC expression. Changes in TRalpha could be compensating for low T3 from HF.

Aspectos genéticos do hipotireoidismo congênito

Hipotireoidismo congênito (HC) afeta cerca de 1:3000 a 1:4000 recém-nascidos (RN). Numerosos genes são essenciais, tanto para o desenvolvimento normal do eixo hipotálamo-hipófise-tireóide quanto para a produção hormonal, e estão associados ao HC. Cerca de 85% do hipotireoidismo primário é denominado disgenesia tireoidiana e evidências sugerem que mutações nos fatores de transcrição (TTF2, TTF1 e PAX-8) e no gene do receptor de TSH podem ser responsáveis pela doença. Os defeitos hereditários da síntese hormonal podem ser devidos a mutações nos genes NIS (natrium-iodide symporter), pendrina, tireoglobulina (TG), peroxidase (TPO). Mais recentemente, mutações no gene THOX-2 têm sido descritas para defeitos na organificacão. O hipotireoidismo central afeta cerca de 1:20.000 RN e tem sido associado com mutações nos fatores transcricionais hipofisários (POUIF1, PROP1, LHX3, HESX1). A síndrome de resistência periférica ao hormônio tireoidiano é uma doença rara que cursa com hipotireoidismo em alguns tecidos e, freqüentemente, está associada a mutações autossômicas dominantes no receptor beta (TRß).

[Growth hormone deficiency after treatment of medulloblastoma with radiotherapy in childhood: case report]

Craniospinal radiation therapy for treatment of brain tumors may result in growth hormone (GH) insufficiency with resultant linear growth retardation, one of the most common complications. We report the case of a 10-year-old boy presenting headache associated to vertigo, nausea and vomiting. A CT scan showed an homogeneous mass in the left cerebelar hemisphere, that was surgically removed. The histopathological examination revealed medulloblastoma and the patient was submitted to craniospinal radiation. He did not present tumor recurrence nor neurological or cognitive deficits during 4 years, but evolved to short stature due to GH deficiency. Nowadays, he is being receiving GH 0,1 U/kg/day and has presented 4cm stature increment after 6 months. The present case highlights the importance in carefully monitoring of children after cranial radiation for oncologic treatment, because they may develop hormonal deficiencies, that can be successfully replaced.

Tumor grade heterogeneity in urothelial bladder carcinoma--proposal of a system using combined numbers

OBJECTIVE

There is no consensus for grading when more than one grade is present in bladder carcinoma. We propose a grading system that considers the primary (most common) and secondary (second most common) grade of bladder cancer. Grade was correlated with stage of the tumors.

MATERIAL AND METHODS

We studied 293 bladder transurethral resections or radical cystectomies. Grade was considered as 1, 2 or 3 according to the 1999 World Health Organization system. The number was repeated when only one grade was seen. A final score was obtained which ranged from 2 to 6. All cases were also graded according to the highest grade area even if it was focal.

RESULTS

According to the highest grade area, the distribution was 80 (74.07%), 27 (25.00%) and 1 (0.92%) for grade 1; 31 (24.03%), 69 (53.48%) and 29 (22.48%) for grade 2; and 0 (0%), 17 (30.35%) and 39 (69.64%) for grade 3, corresponding to the stages Ta, T1 and T2-T3, respectively. Using the system of combined numbers, grade 2 was stratified into subgroups 1 + 2 and 2 + 2 which are statistically different (p < 0.05) when considering stage. In grade 3, there was also a trend for statistical difference (p = 0.066) between grades 2 + 3 and 3 + 3.

CONCLUSIONS

The grading system of combined numbers, stratifies grade 2 into subgroups 1 + 2 and 2 + 2, and grade 3 into subgroups 2 + 3 and 3 + 3 which are statistically different when considering stage. This grading system of combined numbers takes into consideration tumor heterogeneity and may be of value in prospective studies for analysis of prognosis and therapeutic response.

A novel mutation (Q40P) in PAX8 associated with congenital hypothyroidism and thyroid hypoplasia: evidence for phenotypic variability in mother and child

Congenital hypothyroidism associated with thyroid hypoplasia can be caused by several genetic defects, including mutations in the TSHbeta-subunit, the TSH receptor, the G(s)alpha-subunit, and the transcription factor PAX8. Four girls with sporadic congenital hypothyroidism and hypoplastic thyroid glands were analyzed for mutations in PAX8 and TTF2 (FKHL15). Mutations in the coding region of the TSHbeta-subunit gene, the TSH receptor gene, and exons 8 and 9 of G(s)alpha had been excluded previously. Serum TSH concentrations were 150 mU/liter or more, TG levels were within normal limits, and thyroid autoantibodies were absent. Technetium scintigraphies did not reveal the presence of thyroid tissue, but ultrasonography documented hypoplastic, normally located glands. One patient was found to harbor a heterozygous transversion 119A-->C in exon 3 of PAX8 replacing a conserved glutamine by proline in the paired box domain (Q40P). Analysis of her family members revealed that her mother, who has a thyroid gland of normal size and mild, adult-onset autoimmune hypothyroidism, is also heterozygous for this mutation. Functional analyses of the PAX8 Q40P mutation showed impaired binding to a PAX8 response element and absent trans-activation of a thyroid peroxidase promoter luciferase reporter gene. These findings confirm the important role of PAX8 in the development of the thyroid, but they indicate that PAX8 gene mutations may have a variable penetrance or expressivity. The absence of mutations in the coding sequences of the analyzed genes in the three other patients supports the concept that the pathogenesis of congenital hypothyroidism associated with thyroid hypoplasia is diverse.

Clinical and laboratory evaluation of hyperlipemic and hypothyroid patients

OBJECTIVE

To determine the frequency of hypothyroidism in a sample of hyperlipemic patients and evaluate clinical and laboratory factors indicative of thyropathy among them.

METHODS

Fifty-one hyperlipemic patients, grouped according to an earlier or recent diagnosis of their thyroid function into euthyroid and hypothyroid, were evaluated with clinical and laboratory examinations of blood levels of free T4 and TSH (by radioimmunoassay). Patients were on average 46.8 +/- 11.7 years old, predominantly of the female sex (62.5 %); 31 % had a previous diagnosis of hypothyroidism and were under treatment with thyroxin.

RESULTS

Fourteen three percent of patients analyzed had hypothyroidism, which had not been detected before. Differentiating attributes of the groups analyzed were: a predominance of females among the hypothyroid patients and a higher HDL serum concentration among those recently diagnosed.

CONCLUSION

In the present study, new cases of hypothyroidism in hyperlipemic patients were a frequent occurrence, yet few clinical and laboratory data except tests evaluating free T4 and TSH in the blood indicated which patients had thyroid dysfunction.

Thyrotropin receptor mutations in hyperfunctioning thyroid adenomas from Brazil

Constitutively activating mutations in the thyrotropin (TSH) receptor have been identified as a major molecular cause of hyperfunctioning thyroid adenomas. A smaller subset of these benign tumors is caused by constitutive activation of the adenylyl cyclase cascade by somatic mutations in the Gsalpha gene. In this study, we analyzed hyperfunctioning thyroid adenomas from seven Brazilian patients for TSH receptor and G(s)alpha gene mutations. Solitary autonomous thyroid adenomas were identified by ultrasound and scintigraphy, and DNA was extracted from adenomatous and periadenomatous tissue. Exons 9 and 10 of the TSH receptor gene, and exons 8 and 9 of the G(s)alpha gene, were amplified by polymerase chain reaction (PCR) and subjected to direct sequence analysis. Six of seven adenomas harbored heterozygous mutations known to confer constitutive activity to the TSH receptor. In one case, aspartate 619 was substituted by glycine (D619G). In four adenomas, alanine 623 was replaced by valine (A623V). Both residues are located in the third intracellular loop. In one instance, aspartate 633 located in the sixth transmembrane domain was replaced by tyrosine (D633Y). In this patient, one allele also contained a change of aspartate 727 to glutamate (D727E). This substitution is thought to be a polymorphic variant of the wild-type but it has also been associated with toxic multinodular goiters. Functional comparison of D727 with E727 did not reveal differences in basal or TSH-stimulated cyclic adenosine monophosphate (cAMP)-dependent luciferase activity in transiently transfected cells. These results demonstrate a high prevalence of activating TSH receptor mutations in toxic adenomas in this small series from Brazil (approximately 86%). These findings are in agreement with reports from other countries with a marginal iodine intake but contrast with studies from regions with a high iodine intake where these mutations appear to be less prevalent.

Structural analysis of the thyrotropin receptor in four patients with congenital hypothyroidism due to thyroid hypoplasia

Sporadic congenital hypothyroidism is most commonly caused by developmental abnormalities of the thyroid gland. More rarely, it is due to defects in gene products involved in the regulation of the hypothalamic-pituitary-thyroid axis or thyroid hormone synthesis. Loss of function mutations in the thyrotropin (TSH) receptor have been shown to result in resistance to biologically active TSH. In complete resistance to TSH, the thyroid gland is hypoplastic and unable to synthesize and secrete sufficient amounts of thyroid hormones. In partial resistance, referred to as euthyroid hyperthyrotropinemia, the size of the gland and the thyroid hormone levels are normal at the expense of an elevated TSH. Four patients with sporadic congenital hypothyroidism and properly located hypoplastic thyroid glands were included in this study. Serum TSH concentrations were 150 mU/L or higher, serum thyroglobulin levels were within normal limits (6.1 to 8.2 ng/mL; normal range: 2.1 to 32 ng/mL), and thyroid autoantibodies were absent. The coding region of the TSHbeta subunit gene, the TSH receptor gene, and exons 8 and 9 of Gsalpha were analyzed by direct sequencing and found to be normal in all patients. One patient was heterozygous for a G to A transition in the TSHbeta gene resulting in a substitution of alanine by threonine at position -7 of the signal peptide. This substitution was also found in her euthyroid father. In addition, Southern analysis of the TSH receptor gene excluded major structural alterations. These findings support previous reports that indicate that TSH resistance is genetically heterogeneous. In addition to mutations in the TSH receptor or the Gsalpha genes, other genetic defects can lead to an identical phenotype. These observations also suggest that TSH receptor mutations might be a relatively rare cause of congenital thyroid hypoplasia.

Combined pituitary hormone deficiency in an inbred Brazilian kindred associated with a mutation in the PROP-1 gene

Mutations in the pituitary-specific paired-like homeodomain transcription factor PROP-1 result in combined pituitary hormone deficiency (CPHD) which includes all anterior pituitary hormones with the exception of ACTH. In an inbred pedigree with CPHD, direct sequencing of the PROP-1 gene revealed a deletion of two base pairs (301-302delAG) in exon 2, resulting in a frameshift and a premature stop in codon 109 in the homeodomain. The clinical characteristics of this family support the notion that this truncation results in a more severe phenotype than missense mutations in the aminoterminal part of the homeodomain.

Autosomal recessive deficiency of combined pituitary hormones (except ACTH) in a consanguineous Brazilian kindred

Familial hypopituitarism represents a clinically and genetically heterogeneous disorder. In a subset of these families, defects in Pit-I, a transcription factor essential for proper pituitary development have been identified as underlying molecular cause. These patients present extreme short stature, GH, PRL and TSH deficiency but intact ACTH, LH and FSH secretion. The pituitary is usually hypoplastic. In this report we describe a consanguineous family (the parents are first cousins) with thirteen siblings. Of the ten living siblings, four (two males and two females) have panhypopituitarism with severe growth failure. They had evidence of growth hormone, prolactin and gonadotropin deficiencies and developed central hypothyroidism late in life. ACTH secretion was normal. Bone age was retarded and dual-photon bone densitometry indicated severe osteoporosis. Combined provocative tests for pituitary hormones indicated blunted responses for GH, LH, FSH and a modest rise in serum PRL and TSH. A clonidine-test failed to induce pituitary GH response. A corticotropin-releasing factor (CRF) provocative test was conducted after 6 months without the use of prednisone with a normal ACTH response after CRF in the affected sibling. Plasma IGF-I and IGF-BP3 were below normal levels. Serum E2 (females) and serum testosterone (males) levels were very low. MRI evaluation of the pituitary indicated pituitary aplasia in all subjects. The phenotype described in this kindred is different from families reported with Pit-1 mutations. However, it resembles previously published kindreds with similar clinical and biochemical findings. The relative preservation of ACTH suggests a genetic defect early in pituitary gland development.

Chromophobe renal cell carcinoma: clinicopathological study of 7 cases

Chromophobe renal cell carcinoma (CRCC) may be grossly and microscopically confused with oncocytoma. It is now believed that many, if not all, of the so-called malignant oncocytomas or oncocytomas with metastases reported in the literature were indeed chromophobe renal cell carcinomas. CRCC is characteristically positive for colloidal iron and shows cytoplasmic microvesicles in electron microscopy. This study of CRCC is thought to be the first one done in Latin America. Of a total of 106 renal epithelial neoplasms, 7 (6.6%) fulfilled the criteria for chromophobe renal cell carcinoma. This frequency in Brazil is similar to that in other parts of the world. There was no difference in age, sex, and race distribution of CRCC compared to usual renal epithelial tumors. Grossly, the CRCC ranged in size from 3.5 to 20 cm (average: 10.2 cm) in greatest dimension. Most frequently, the tumor was brown on the cut surface. The growth pattern showed compact areas in all tumors and, in most of the cases, both clear and eosinophilic cellular subtypes were seen. The electron microscopic findings favor an origin of the microvesicles from outpouchings of the outer membrane of mitochondria. The strong positivity for colloidal iron in spite of the destruction of the cytoplasmic vesicles in paraffin-embedded specimens seems to indicate that the acid mucopolysaccharides are not located inside the microvesicles. By the time of diagnosis, only one case had regional lymph node metastases and this particular case was the only one mixed (associated with the usual renal cell carcinoma). The follow-up examination after nephrectomy showed that prognosis seems to be favorable in CRCC, except when the tumor coexists with the usual renal cell carcinoma.

Autosomal recessive deficiency of combined pituitary hormones (except ACTH) in a consanguineous Brazilian kindred

Familial hypopituitarism represents a clinically and genetically heterogeneous disorder. In a subset of these families, defects in Pit-I, a transcription factor essential for proper pituitary development have been identified as underlying molecular cause. These patients present extreme short stature, GH, PRL and TSH deficiency but intact ACTH, LH and FSH secretion. The pituitary is usually hypoplastic. In this report we describe a consanguineous family (the parents are first cousins) with thirteen siblings. Of the ten living siblings, four (two males and two females) have panhypopituitarism with severe growth failure. They had evidence of growth hormone, prolactin and gonadotropin deficiencies and developed central hypothyroidism late in life. ACTH secretion was normal. Bone age was retarded and dual-photon bone densitometry indicated severe osteoporosis. Combined provocative tests for pituitary hormones indicated blunted responses for GH, LH, FSH and a modest rise in serum PRL and TSH. A clonidine-test failed to induce pituitary GH response. A corticotropin-releasing factor (CRF) provocative test was conducted after 6 months without the use of prednisone with a normal ACTH response after CRF in the affected sibling. Plasma IGF-I and IGF-BP3 were below normal levels. Serum E2 (females) and serum testosterone (males) levels were very low. MRI evaluation of the pituitary indicated pituitary aplasia in all subjects. The phenotype described in this kindred is different from families reported with Pit-1 mutations. However, it resembles previously published kindreds with similar clinical and biochemical findings. The relative preservation of ACTH suggests a genetic defect early in pituitary gland development.

Triiodothyronine mimics the effects of estrogen in breast cancer cell lines

MCF-7 (estrogen receptor positive--ER+) and MDA-MB-231 (estrogen receptor negative--ER-) are human breast cancer cell lines which express functional thyroid hormone receptors (c-erb A alpha1 and c-erb beta1) as indicated by stimulation of mitochondrial alpha-glycerophosphate dehydrogenase. In MCF-7, mimicking E2, T3 stimulated growth in a dose-dependent (10(10) M - 10(-8) M) manner, induced the expression of progesterone receptor and growth factor TGFalpha mRNAs and inhibited that of TGFbeta mRNA; T3 also increased progesterone binding and LDH5 isozyme activities. None of these effects were observed in (ER-) MDA-MB-231 cells. 10(-6) M tamoxifen (TAM) reverted growth stimulation, suppressed progesterone receptor and TGFalpha mRNA induction and restored TGFbeta mRNA to control levels in T3-treated MCF-7 cells. That T3 is acting in MCF-7 cells via its binding to ER is suggested by the immunoprecipitation of pre-bound 125I-T3 from MCF-7 nuclear extracts by an ER-specific monoclonal antibody and by the displacement of 3H-estradiol binding to ER by radioinert T3.

Modulation of insulin secretion and 45Ca2+ efflux by dopamine in glucose-stimulated pancreatic islets

1. The effect of dopamine on calcium efflux and insulin secretion is examined in the present study. For this purpose, islets isolated from adult Wistar rats were perfused or incubated at 37 degrees C for 60 min. 2. The results obtained from perfused islets indicate that 100 microM dopamine, in the presence of 5.6 mM glucose, increases insulin secretion and causes a modest elevation of 45Ca2+ efflux. However, glucose stimuli (from 5.6 to 16.7 mM) provoked an unexpected reduction of insulin release, with no alteration in calcium efflux, when 100 microM dopamine was present in the perfusion medium. 3. Similar findings were obtained in incubated islets when the prolonged effect of dopamine was investigated. 4. The observations described above led us to conclude that bioactive amines might play an important role in the modulation of the glucose-induced insulin secretion.

Obesity is the major cause of alterations in insulin secretion and calcium fluxes by isolated islets from aged rats

To investigate the alterations in insulin secretion induced by aging, 2-month-old, 12-month-old, and 12-month old lean rats (submitted to a caloric restriction during the last month that causes a weight loss of approximately 20%) were studied. As expected, glucose intolerance and increased insulin response were observed during IV-GTT in 12-month-old rats. These effects were, however, reversed by weight loss. Insulin secretion was investigated in isolated islets both during static incubation and perifusion. In 12-month-old rats insulin secretion and 45Ca2+ efflux were lower only in the second phase of the hormonal secretion, suggesting an involvement of voltage-sensitive calcium channels in these phenomena. Considering that in vivo and in vitro alterations were reversed after weight loss, it is possible to conclude that obesity is probably a major cause of impaired insulin secretion in 12-month-old albino rats. Since 14C-glucose metabolism was not changed in islets from aged rats, the effect of obesity on insulin secretion is not due to altered glucose metabolism in pancreatic B-cells.

Insulin secretion in Walker 256 tumor cachexia

The effect of cachexia on insulin secretion was examined in adult male rats. Isolated islets of Langerhans from Walker 256 tumor-bearing rats secreted less insulin by glucose stimuli as compared with the control group; this was accompanied by significant change in 45Ca2+ outflow rate. Reduced insulin secretion to glucose stimuli in tumor-bearing rats probably led to low insulinemia (one-third). These findings indicate that reduced insulin secretion is probably an important factor for the development of cachexia in Walker 256 tumor-bearing rats.