Publications (6)10.37 Total impact
- Diabetes care 09/2007; 30(8):2135-7. · 7.74 Impact Factor
- Arquivos Brasileiros de Endocrinologia & Metabologia 07/2006; 50(3):573-4. · 0.88 Impact Factor
- Arquivos Brasileiros de Endocrinologia & Metabologia 07/2004; 48(3):429-30. · 0.88 Impact Factor
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ABSTRACT: Pregnancy induces a series of physiological modifications that include a significant elevation of thyroxine-binding globulin (TBG) levels. This elevation interferes in the serum levels of total thyroxine and stresses the use of free thyroxine (FT4), together with TSH measurement, as the first line tests in the evaluation of thyroid function in pregnancy. A careful definition of the normal values for FT4 during pregnancy is paramount for the study of thyroid abnormalities, since minimal dysfunctions can result in significant fetal abnormalities. We studied 132 normal pregnant women, from 6 to 38 weeks of gestation, and the serum FT4 measured by an indirect two-step assay (normal values for non-pregnant women: 0.7 to 1.5 ng/dL; mean+/-SD 0.98+/-0.14 ng/dL, n= 797) showed values between 0.5 and 1.3 ng/dL; mean+/-SD of 0.78+/-0.16 ng/dL, values significantly lower than the observed in non-pregnant women (P<0.0001). Values tended to decline progressively throughout pregnancy, with a significant negative correlation with TBG levels (rs= -0.51, P<0.0001), as well as with weeks of gestation (rs= -0.649, P<0.0001). TSH levels did not show any correlation with gestational age. Our data corroborate the need of a precise definition of FT4 normal values during pregnancy, aiming a better laboratory evaluation of thyroid dysfunctions in this group of patients.Arquivos Brasileiros de Endocrinologia & Metabologia 04/2004; 48(2):305-9. · 0.88 Impact Factor
- Arquivos Brasileiros De Endocrinologia E Metabologia - ARQ BRAS ENDOCRINOL METABOL. 01/2004; 48(3).
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ABSTRACT: N THE CLINICAL SETTING, assessment of insulin resistance (IR) can be made without any laboratory test, but by evaluating data such as weight or BMI, among others. However, in the last few years laboratories have been asked to provide direct or indirect measures of IR. Homeostatic model assessment (HOMA-IR) is a simple and inexpensive technique to evaluate IR from basal (fasting) glucose and insulin or C-peptide concen- trations, validated against a variety of physiological methods (1-4). To va- lidate the potential use of HOMA-IR values in clinical practice, it is impor- tant to establish its distribution in a sample of normoglycemic individuals from a population with the same genetic background (2). In this regard, we aim to describe the distribution of HOMA-IR values in a large sample of Brazilian population. We analyzed retrospectively fasting insulin and glucose levels in 1,898 Brazilian adults (25% males, age range 18-90 years). All had fasting glucose < 99 mg/dL, none on insulin secretagogues or insulin use. Insulin levels were determined by a time-resolved fluroim- munoassay (Perkin Elmer). HOMA-IR was calculated with the following: fasting serum insulin (µU/ml) + fasting plasma glucose (mmol/l)/22.5 (1). In the entire group the mean HOMA-IR was 1.8 ± 0.9 (M ± SD). Taking into account the relationship between adiposity and insulin levels and IR, we stratified the group according to the BMI (kg/m2) in terciles: < 25 (n= 883); 25-30 (n= 624) and > 30 (n= 391) (table 1). A recent pu- blication in a group of 312 non-obese, normoglicemic Brazilian subjects found a mean HOMA-IR of 1.7, and a threshold value for insulin resis- tance of 2.71 (3). The use of HOMA -IR to quantify insulin sensitivity can be helpful in clinical practice for comparisons of insulin sensitivity, gather- ing of longitudinal data in subjects at risk for development of abnormal glucose tolerance. Also, HOMA -IR can be used to assess longitudinal changes of IR in patients with diabetes in order to examine the natural his- tory of the disease and to assess the effects of treatment, as demonstrated for example in the U.K. Prospective Diabetes Study (UKPDS) (5). Our results can be useful as a reference for further Brazilian studies using HOMA-IR values as a measure of IR in this particular population.
Universidade Federal de São PauloSan Paulo, São Paulo, Brazil