Insulin resistance, beta-cell function, and glucose tolerance in Brazilian adolescents with obesity or risk factors for type 2 diabetes mellitus.

OBJECTIVE: To evaluate insulin resistance (IR), beta-cell function, and glucose tolerance in 119 Brazilian adolescents with obesity or risk factors (RF) for type 2 diabetes mellitus (T2DM). STUDY DESIGN: We analyzed weight (kg), height (m), body mass index (BMI; kg/m(2)), waist (W; cm), acanthosis nigricans (AN), systolic and diastolic blood pressure (SBP and DBP; mm Hg), fasting plasma glucose (FPG), and 2-h plasma glucose (2hPG) on oral glucose tolerance test (OGTT; 1.75 g of glucose/weight), lipid profile [total cholesterol (TC), fractions, and triglycerides (TGs)], fasting insulin (FI) and 2-h insulin on OGTT (2hI-RIA), HOMA-B (%; beta-cell function--HOMA program), HOMA-S (%; insulin sensitivity--HOMA program) and HOMA-IR [fasting plasma insulin (mU/ml)xfasting plasma glucose (mmol/L)/22.5]. Division according to number of RF-family history of T2DM (FHT2DM), obesity, hypertension, dyslipidemia, polycystic ovary syndrome (PCOS), and AN. G1: subjects with no or one RF; G2: subjects with two or more RFs. Statistical data were nonparametrical. RESULTS: Fasting plasma glucose (G2: 81.6+/-10.2 vs. G1: 79.8+/-9.9 mg/dl) and 2hPG (88.1+/-18.0 vs. 87.0+/-19.9 mg/dl) were not different between G2 (n=67) and G1 (n=52), and all adolescents had normal glucose tolerance (NGT). Fasting insulin (13.0+/-7.9 vs. 7.6+/-3.9 microIU/ml; P<.001) and 2hI (60.2+/-39.1 vs. 38.3+/-40.0 microIU/ml; P<.001), HOMA-B (169.1+/-131.6% vs. 106.1+/-39.9%; P<.001), and HOMA-IR (2.62+/-1.7 vs. 1.52+/-0.8; P<.001) were higher in G2. HOMA-S (92.5+/-59.5% vs. 152.2+/-100.5%; P<.001) was also lower in this latter group. CONCLUSION: Brazilian adolescents with two or more RFs for the development of T2DM have higher IR and beta-cell function and lower insulin sensitivity. However, adolescents with impaired glucose tolerance (IGT) or DM have not been found, differently from similar studies. Differences in ethnic background, environment, and lifestyle factors may account for this disparity.

Comparaçäo entre os métodos de cromatografia de troca iônica e cromatografia de afinidade para a dosagem de hemoglobina glicolisada (HbA1) / Comparison between ion exchange chromatography and affinity chromatography methods for the measurement of the glycosylated hemoglobin (bA1)

O método de cromatografia de afinidade para a dosagem de hemoglobina foi comparado com o método de cromatografia de troca iônica em minicolunas. Os resultados obtidos em indivíduos normais e pacientes diabéticos pelos dois procedimentos tiveram uma alta correlaçäo (r = 0,91), mas os valores obtidos foram mais baixos pelo ensaio de afinidade. As concentraçöes aparentes de HbA1 pelo método de troca iônica estiveram acima do normal nos pacientes urêmicos e nos homozigotos para anemia falciforme. Todavia, nestes estados com baixa sobrevida dos eritrócitos as concentraçöes de HbA1 pela cromatografia de afinidade estiveram normais ou abaixo do normal. O método de cromatografia de afinidade parece ser mais específico do que o método de troca iônica na medida da hemoglobina glicosilada