Ana Paula Santin

Role of Estrogen in Thyroid Function and Growth Regulation

Thyroid diseases are more prevalent in women, particularly between puberty and menopause. It is wellknown that estrogen (E) has indirect effects on the thyroid economy. Direct effects of this steroid hormone on thyroid cells have been described more recently; so, the aim of the present paper was to review the evidences of these effects on thyroid function and growth regulation, and its mechanisms. The expression and ratios of the two E receptors, α and β, that mediate the genomic effects of E on normal and abnormal thyroid tissue were also reviewed, as well as nongenomic, distinct molecular pathways. Several evidences support the hypothesis that E has a direct role in thyroid follicular cells; understanding its influence on the growth and function of the thyroid in normal and abnormal conditions can potentially provide new targets for the treatment of thyroid diseases.

Blood Antioxidant Parameters in Sickle Cell Anemia Patients in Steady State

Sickle cell anemia (SCA) is a hereditary disorder with higher potential for oxidative damage due to chronic redox imbalance in red cells. We measured antioxidant enzymes including catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD). We also determined oxidative damage of proteins in hemolysate of red blood cells (RBCs) and plasma (carbonyl assay). We characterized the membrane damage in terms of lipid peroxidation by accumulation of malonaldehyde (MDA) by HPLC in 30 healthy controls and 20 SCA patients in steady-state condition. Twenty (9 males/11 females) adult SCA patients and 30 healthy controls were studied. All patients and control subjects had antioxidant (CAT, GPx, SOD, carbonyl and MDA) and hematological parameters done. Our data show that SCA patients had significant higher GPx and SOD activities than healthy controls. Carbonyl assay was noted in plasma but not in hemolysate. An enhanced production of MDA was observed in the serum of SCA patients. Our data support the growing evidence that patients with SCA are subjected to chronic oxidative stress and are able to oxidative damage in biological macromolecules such as proteins and lipids.

Prognosis of Thyroid Cancer Related to Pregnancy: A Systematic Review

Differentiated thyroid cancer (DTC) is the second most common cancer in pregnancy. Its management is a challenge for both doctors and patients, and the best timing for surgery is unclear. A systematic review evaluating the prognosis of DTC in pregnant patients was conducted. After reviewing 401 unique citations and 54 full texts, 4 studies that compared the prognosis of patients with DTC related to pregnancy (DTC diagnosed during pregnancy or within 12 months after childbirth) or not were included. In two studies the primary outcome was overall survival, in one study the primary outcomes were recurrent disease and death related to thyroid cancer, and in one study the primary outcome was recurrent or persistent disease. In the first two studies, there was no difference in overall survival in patients with pregnancy-related DTC, when compared with matched controls; in one study, there was no difference in death caused by DTC nor recurrence in DTC related to pregnancy. Nevertheless, in a recent retrospective study, a higher rate of recurrent or persistent DTC was observed in patients with DTC related to pregnancy. There are not many studies on which to base treatment decisions in pregnant patients with DTC.

Validation of Reference Genes for Normalizing Gene Expression in Real-Time Quantitative Reverse Transcription PCR in Human Thyroid Cells in Primary Culture Treated with Progesterone and Estradiol

The use of appropriately chosen reference genes for normalizing gene expression in real-time quantitative reverse transcription polymerase chain reaction is an important step in the analysis of gene expression, compensating for several technical factors. As female sex hormones have been shown to influence growth and differentiation of thyroid follicular cells, the establishment of normalizer genes in human thyroid cells in primary culture, treated with progesterone, and estradiol, is important to evaluate their effect on gene expression in these cells, so candidate reference genes were studied. β-Actin, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), β2-microglobulin (B2M), and TATA box binding protein (TBP) were evaluated in thyroid cells treated with estradiol, progesterone, and their inhibitors. Normfinder software was used to assess the stability of the genes and identified β-actin as the gene with adequate stability and lower inter-group variations, when compared to TBP, B2M, and GAPDH.

Prevalence of common α-thalassemia determinants in south Brazil: importance for the diagnosis of microcytic anemia

Alpha thalassemia has not been systematically investigated in Brazil. In this study, 493 unrelated individuals from the southernmost Brazilian state of Rio Grande do Sul were screened for deletional forms of α-thalassemia. One hundred and one individuals had microcytic anemia (MCV < 80 fL) and a normal hemoglobin pattern (Hb A 2 < 3.5% and Hb F < 1%). The subjects were screened for - α3.7 , - α4.2 , - α20.5 , — SEA and — MED deletions but only the - α3.7 allele was detected. The - α3.7 allele frequency in Brazilians of European and African ancestry was 0.02 and 0.12, respectively, whereas in individuals with microcytosis the frequency was 0.20. The prevalence of α-thalassemia was significantly higher in individuals with microcytosis than in healthy individuals (p = 0.001), regardless of their ethnic origin. There were also significant differences in the hematological parameters of individuals with - α3.7 / αα, - α3.7 /- α3.7 and β-thalassemia trait compared to healthy subjects. These data suggest that α-thalassemia is an important cause of microcytosis and mild anemia in Brazilians.

Neonatal screening for hemoglobinopathies: results of a public health system in South Brazil.

AIM The aim of this study was to estimate the prevalence of hemoglobinopathies in South Brazil. METHODS Samples of dried blood spots collected by heel prick in neonates were evaluated by isoeletric focusing and/or high-performance liquid chromatography techniques. All variants were characterized at the molecular level. RESULTS A total of 437,787 samples were evaluated. Among these, 6391 showed an abnormal hemoglobin pattern. These included 48 cases (0.01%) of sickle cell disorders (33 hemoglobin SS [Hb SS], 7 Hb SC, 7 Hb S/beta thalassemia, 1 Hb SD), 1 neonate who was homozygous for beta thalassemia, 6272 (1.4%) newborns who were heterozygous for Hb S, C, or D, and 71 (0.02%) neonates who were carriers for rare hemoglobin variants. Most of these rare variants were identified for the first time in Brazil. CONCLUSIONS Comparing these results with those obtained in other Brazilian regions, we observe a highly heterogeneous distribution. This knowledge is useful in healthcare planning and allocation of resources, as well as identifying at-risk couples, which will assist with disease prevention.

Glucose-6-phosphate-dehydrogenase deficiency and its correlation with other risk factors in jaundiced newborns in Southern Brazil.

OBJECTIVE To evaluate the correlation between glucose-6-phosphate-dehydrogenase (G6PD) deficiency and neonatal jaundice. METHODS Prospective, observational case-control study was conducted on 490 newborns admitted to Hospital de Clínicas de Porto Alegre for phototherapy, who all experienced 35 or more weeks of gestation, from March to December 2007. Enzymatic screening of G6PD activity was performed, followed by PCR. RESULTS There was prevalence of 4.6% and a boy-girl ratio of 3:1 in jaundiced newborns. No jaundiced neonate with ABO incompatibility presented G6PD deficiency, and no Mediterranean mutation was found. A higher proportion of deficiency was observed in Afro-descendants. There was no association with UGT1A1 variants. CONCLUSIONS G6PD deficiency is not related to severe hyperbilirubinemia and considering the high miscegenation in this area of Brazil, other gene interactions should be investigated.

Polymorphic variants of UGT1A1 in neonatal jaundice in southern Brazil.

Alterations in the hepatic conjugation of bilirubin due to uridyl-diphosphate-glucuronosyltransferase 1A1 (UGT1A1) polymorphisms have been proposed as risk factors to neonatal jaundice. Herein, we estimated the frequency of genotypes of the promoter region of UGT1A1 gene in newborns and evaluated its association with severe hyperbilirubinemia. Prospective study of cases and controls including all newborns admitted for phototherapy at HCPA, Brazil, during 9 months; 490 babies were enrolled and PCR was performed. Polymorphic genotypes were detected in 16% of the patients and 7 of the 10 possible genotypes were identified with higher prevalence of polymorphisms in Afro-descendants. In this sample, the variants of UGT1A1 were not associated to severe hyperbilirubinemia; other genic factors should be sought in this high miscegenation area of Brazil.

Prevalence of UGT1A1 Gene Polymorphism in Patients with Hemolytic Anemia in Southern Brazil

The aim of the work was to determine the variation of UGT1A1 genotypes in patients with hemolytic anemia in the southern Brazil. Three hundred twenty-three patients with hemolytic anemia were genotyped for UGT1A1 along with 232 controls. Allelic and genotypic distribution did not differ among studied groups. The TA7/TA7 genotype presented a frequency that ranged from 3.2% to 18.0% (nonsignificant). Alleles TA5 and TA8 were also found in the sample, even though southern Brazil is a major Caucasoid region. Genotype prevalence was very similar to those of African origins, reflecting the diversity of ethnic origins and the high degree of admixture in southern Brazil. Further studies should be conducted to correlate the modulating role of UGT1A1 polymorphism with the clinical conditions of each patient with hemolytic anemia.

Determinação da acurácia do método qualitativo da medida da atividade da glicose-6-fosfato desidrogenase

Glucose-6-phosphate dehydrogenase deficiency (G6PD) is a public health problem which affects about 400 millions of people all over the world. Some methods that measure the activity of G6PD have already been developed. Thus, the aim of this study was to evaluate the accuracy of the Brewers method compared with a standard reference and estimate the prevalence of G6PD deficiency in the sample. A cross-sectional study of a group of patients in HCPA presenting with jaundice was carried out from June 2004 to May 2005. Samples were processed by the metahaemoglobin reduction test (Brewers method) and by the method of Haemoglobin Normalization, which was used as the standard reference. A total of 173 patients were analyzed for G6PD activity. The ages varied from one day to 82 years old with 66% of the sample being less than 16 days old. The mean activity and standard deviation of G6PD for the analyzed sample was 17.67 ± 5.66 U/gHb. The estimated frequencies of G6PD deficiency for the standard reference and Brewers method were 13 (7.7%) subjects (total or partial deficiency) and 14 (8.67%), respectively. When the Brewers method was compared with the quantitative method of Hemoglobin Normalization, it showed a sensitivity of 92.8% and specificity of 98.7%. As G6PD deficiency predominates in our society, low cost tests, such as the Brewers test can be used for screening this deficiency, mainly to monitor newborn babies who are at risk of developing jaundice.