Factores asociados a insulinemia en población general adolescente.

Objectives: To identify factors that correlate with insulin values and to examine its independent associations among adolescents. Methods: A cross-sectional population-based study was conducted among adolescents aged 12-16,9 years old. A multi-stage stratified cluster random sampling method was employed. Anthropometric measurements and nutritional survey were performed, and fasting blood samples for insulin were obtained. Statistics: Multiple lineal regression. Results: 379 adolescents were included. Mean age was 14.08 ± 1.30 years. Factors associated with higher fasting insulin levels were puberty [ 4.55 (95% IC 0.42-8.69)], abdominal obesity [ 6.11 (95% IC 3.93-8.29)] and to be born small for gestational age (SGA) [ 7.45 (95% IC 2.47-12.44)]. It was observed a negative association between the regular intake of olive oil at home and insulin values [ -4.14 (95% IC -7.31- -0.98)]. Conclusions: Abdominal obesity and SGA were factors associated with higher fasting insulin values. In contrast, the regular intake of olive oil at home was an independent protective factor.

Disruption of GIP/GIPR axis in human adipose tissue is linked to obesity and insulin resistance.

CONTEXT Glucose-dependent insulinotropic peptide (GIP) has a central role in glucose homeostasis through its amplification of insulin secretion; however, its physiological role in adipose tissue is unclear. OBJECTIVE Our objective was to define the function of GIP in human adipose tissue in relation to obesity and insulin resistance. DESIGN GIP receptor (GIPR) expression was analyzed in human sc adipose tissue (SAT) and visceral adipose (VAT) from lean and obese subjects in 3 independent cohorts. GIPR expression was associated with anthropometric and biochemical variables. GIP responsiveness on insulin sensitivity was analyzed in human adipocyte cell lines in normoxic and hypoxic environments as well as in adipose-derived stem cells obtained from lean and obese patients. RESULTS GIPR expression was downregulated in SAT from obese patients and correlated negatively with body mass index, waist circumference, systolic blood pressure, and glucose and triglyceride levels. Furthermore, homeostasis model assessment of insulin resistance, glucose, and G protein-coupled receptor kinase 2 (GRK2) emerged as variables strongly associated with GIPR expression in SAT. Glucose uptake studies and insulin signaling in human adipocytes revealed GIP as an insulin-sensitizer incretin. Immunoprecipitation experiments suggested that GIP promotes the interaction of GRK2 with GIPR and decreases the association of GRK2 to insulin receptor substrate 1. These effects of GIP observed under normoxia were lost in human fat cells cultured in hypoxia. In support of this, GIP increased insulin sensitivity in human adipose-derived stem cells from lean patients. GIP also induced GIPR expression, which was concomitant with a downregulation of the incretin-degrading enzyme dipeptidyl peptidase 4. None of the physiological effects of GIP were detected in human fat cells obtained from an obese environment with reduced levels of GIPR. CONCLUSIONS GIP/GIPR signaling is disrupted in insulin-resistant states, such as obesity, and normalizing this function might represent a potential therapy in the treatment of obesity-associated metabolic disorders.

Rapid diagnosis of human brucellosis by peripheral-blood PCR assay.

A single-step PCR assay with genus-specific primers for the amplification of a 223-bp region of the sequence encoding a 31-kDa immunogenetic Brucella abortus protein (BCSP31) was used for the rapid diagnosis of human brucellosis. We examined peripheral blood from 47 patients, with a total of 50 cases of brucellosis, and a group of 60 control subjects, composed of patients with febrile syndromes of several etiologies other than brucellosis, asymptomatic subjects seropositive for Brucella antibodies, and healthy subjects. Diagnosis of brucellosis was established in 35 cases (70%) by isolation of Brucella in blood culture and in the other 15 cases (30%) by clinical and serological means. The sensitivity of our PCR assay was 100%, since it correctly identified all 50 cases of brucellosis, regardless of the duration of the disease, the positivity of the blood culture, or the presence of focal forms. The specificity of the test was 98.3%, and the only false-positive result was for a patient who had had brucellosis 2 months before and possibly had a self-limited relapse. In those patients who relapsed, the results of our PCR assay were positive for both the initial infection and the relapse, becoming negative once the relapse treatment was completed and remaining negative in the follow-up tests at 2, 4, and 6 months. In conclusion, these results suggest that the PCR assay is rapid and easy to perform and highly sensitive and specific, and it may therefore be considered a useful tool for diagnosis of human brucellosis.

Strategy for optimizing DNA amplification in a peripheral blood PCR assay used for diagnosis of human brucellosis.

We studied two of the possible factors which can interfere with specific DNA amplification in a peripheral-blood PCR assay used for the diagnosis of human brucellosis. We found that high concentrations of leukocyte DNA and heme compounds inhibit PCR. These inhibitors can be efficiently suppressed by increasing the number of washings to four or five and decreasing the amount of total DNA to 2 to 4 microg, thereby avoiding false-negative results.