Epigenetic characterization of the H19/IGF2 locus in calf clones placenta / Caracterização epigenética do locus H19/IGF2 na placenta de bezerros clones

Somatic Cell Nuclear Transfer (SCNT-Cloning) is a promising technique in many areas and is based on genetically identical individuals. However, its efficiency is low. Studies suggest that the leading cause is inadequate epigenetic reprogramming. This study aimed to characterize the methylation pattern of the exon 10 regions of the IGF2 gene and the Imprinting Control Region (ICR) of the H19 gene in the placenta of cloned calves. For this study, female and male cloned calves presenting different phenotypes were used. Genomic DNA from these animals' placenta was isolated, then treated with sodium bisulfite and amplified to the ICR/H19 and IGF2 loci. PCR products were cloned into competent bacteria and finally sequenced. A significant difference was found between controls and clones with healthy phenotypes for the ICR/H19 region. In this region, controls showed a hemimethylated pattern, as predicted in the literature due to this region has an imprinted control, while clones were showed less methylated. For the IGF2, no significant differences were found between controls and clones. These results suggest that different genomic regions in the genome may be independently reprogrammed and that failures in reprogramming the DNA methylation patterns of imprinted genes may be one of the causes of the low efficiency of SCNT.(AU)

A Transferência Nuclear de Células Somáticas (TNCS-Clonagem) é uma técnica promissora em várias áreas, e se baseia na produção de indivíduos geneticamente idênticos. No entanto, sua eficiência é baixa. Estudos sugerem que a principal causa seja uma reprogramação epigenética inadequada. O objetivo desse trabalho é caracterizar o padrão de metilação da região éxon 10 do gene IGF2 e da Região Controladora de Imprinting (ICR) do gene H19 na placenta de bezerros clonados. Para a execução do trabalho foram selecionados clones bovinos fêmeas e machos, apresentando diferentes fenótipos. O DNA da placenta desses animais foi extraído, e em seguida foi tratado com bissulfito de sódio e amplificado para os loci ICR/H19 e IGF2. Os produtos da PCR foram clonados em bactérias competentes e, por fim, sequenciados. Foi encontrada uma diferença significativa entre os controles e os clones com fenótipos saudáveis para a região da ICR/H19. Nesta região, os controles tiveram um padrão hemimetilado, como previsto pela literatura, devido essa região ser imprinted. Enquanto os clones encontravam-se menos metilados. Para a região do éxon 10 do IGF2, não foi encontrada diferença significativa entre controles e clones. Estes resultados sugerem que as diferentes regiões do genoma podem se reprogramar independente umas das outras e que falhas na reprogramação do padrão de metilação do DNA de genes imprinted podem ser uma das causas da baixa eficiência da TNCS.(AU)

Hipoglucemia inducida por carcinoma adrenal / Adrenal carcinoma induced hypoglycemia

El carcinoma suprarrenal es una neoplasia maligna infrecuente y de mal pronóstico. La presentación clínica más común es originada por la producción hormonal excesiva, mientras que el desarrollo de hipoglucemia sintomática es excepcional. Presentamos el caso de una mujer de 37 años que ingresó al hospital por síntomas de hipoglucemias graves, hipertensión arterial, hipopotasemia y amenorrea secundaria. En el laboratorio se halló hipoglucemia con insulina inhibida y niveles de andrógenos en rango tumoral. La tomografía computarizada (TC) de abdomen y pelvis mostró voluminosa formación heterogénea de aspecto sólido sin plano de clivaje con respecto al parénquima hepático e intenso realce con contraste. Luego de la extirpación de la masa retroperitoneal, evolucionó con valores de glucemia y potasemia normales, estabilizó la presión arterial y recuperó los ciclos menstruales.

Adrenal carcinoma is a rare malignancy of poor prognosis. The most common clinical presentation is secondary to hormone production, while the development of symptomatic hypoglycemia is exceptional. We report the case of a 37 year old-woman admitted to hospital with severe hypoglycemia, hypertension, hypokalemia and amenorrhea. In the laboratory we found hypoglycemia, with low insulin levels, and androgen levels in tumor range. CT of abdomen and pelvis showed a heterogeneous lesion of solid appearance without a cleavage plane relative to liver parenchyma, and intense contrast enhancement. Retroperitoneal mass was removed, and the patient evolved without complications, blood glucose and potassium were normalized, blood pressure stabilized and menstrual cycles recovered.

Maternal and cord blood levels of insulin-like growth factors--I and--II and insulin-like growth factor binding protein-1: correlation with birth weight and maternal anthropometric indices.

OBJECTIVES: To study the correlation of maternal and cord blood insulin like growth factor (IGF)-I and -II and IGF binding protein (IGFBP)-1 levels with birth weight and maternal anthropometric indices. DESIGN: Longitudinal prospective study. SETTING: Academic Institutions and a Tertiary Care Maternity Hospital. PARTICIPANTS: Women with uncomplicated singleton pregnancy (N = 35) and their newborns. MEASUREMENTS: Maternal weight, height, symphysiofundal height and serum levels of IGF-I, IGF-II, IGFBP-1 were measured thrice during the antenatal period, within 24 h of delivery and at 6 weeks and 6 months postpartum. Newborn anthropometric indices were recorded at birth, and at 6 weeks and 6 months of age. Cord blood levels of IGF-1, IGF-II, IGFBP-1, paternal height and weight, and placental weight measured. RESULTS: Maternal and cord blood IGF-I levels were lower than values reported for Caucasians. All newborns showed adequate growth at birth, and up to 6 months of age. Cord blood IGF-1 positively correlated with chest circumference (r = 0.4532, P = 0.0262), IGFBP-1, negatively with birth weight (r = -0.4024, P = 0.0461) and IGF-II had no effect. Cord blood IGF-I positively correlated with maternal levels at 28 +/- 2 (r = 0.4571, P = 0.0247) and 36 +/- 2 (r = 0.4291, P = 0.0364) weeks of amenorrhoea, whereas IGF-II and IGFBP-1 did not correlate with maternal values. Maternal IGF-I, IGF-II and IGFBP-1 did not correlate with newborn or maternal anthropometric indices. Placental weight correlated significantly with birth weight (r = 0.5299, P = 0.0348) and head circumference (r = 0.5031, P = 0.0470). CONCLUSIONS: Cord blood IGFBP-1 and placental weight appear to be determinants of birth weight variation even among appropriately grown for gestational age newborns.

Insulin-like growth factors and their binding proteins in children with IDDM.

The structure of insulin-like growth factor (IGF), especially IGF-I, and its receptor is similar to that of insulin. Therefore, the changes of IGFs and IGF-binding proteins may be related to glucose homeostasis in children with insulin dependent diabetes mellitus (IDDM). Sixty-three fasting blood samples of 21 children with IDDM attending 3 consecutive diabetic clinics were studied. The HbA1c progressively decreased from the 1st to the 3rd visit. IGF-I levels, both total and free forms, were not significantly different from that of control. IGFBP-3 levels in 3 visits (3406+/-305, 3376+/-252, and 2406+/-247 ng/mL) were significantly lower than that of control (5020+/-415 ng/mL) with the p value of 0.007, 0.002, and < 0.001 respectively. IGFBP-1 levels in the 1st and 2nd visits (102.1+/-12.9 and 114.1+/-14.5 ng/mL) were significantly higher than that of control (60.1+/-15.2 ng/mL) with the p value of 0.03 and 0.01 respectively, but not in the 3rd visit. IGF-I level had a positive correlation with IGFBP-3 (R=0.56, p=0.01) and free IGF-I (R=0.53, p=0.01). Free IGF-I had a negative correlation with IGFBP-1 (R=-0.64, p=0.01). IGF-II at the 15 visit had a negative correlation with HbA1c (R=-0.49, p=0.047). The authors found no correlations between IGF-I, IGFBP-3, free IGF-I, IGFBP-1 and HbA1c in the study. The patients' height SDS followed the genetic height potential. It was, therefore, postulated that a near normal free IGF-I level in diabetic children resulted from a balance of interaction between IGFBP-1 and IGFBP-3 to total IGF-I in order to keep the normal metabolic status as much as possible.

Serum insulin-like growth factor (IGF)-I and IGF-binding proteins in lung cancer patients

Many studies have shown that insulin-like growth factors (IGF-I & IGF-II) are implicated in the autocrine and paracrine growth of various tumors. Alterations in serum IGFs and IGF-binding proteins (IGFBPs) profiles have been reported in lung cancer. In this study, we measured serum levels of IGF-I and IGFBPs in 41 patients with lung cancer (small cell lung cancer, SCLC, 9; non-small cell lung cancer, NSCLC, 32) by radioimmunoassay and Western ligand blot (WLB). The serum IGF-I level in patients with lung cancer was significantly lower than in controls (207.9+/-62.6 vs 281.3+/-53.9 ng/mL, p0.05). The concentration of IGFBP-3 in lung cancer was 48% of that found in controls by WLB. The serum level of IGFBP-2 was markedly elevated in patients with lung cancer compared with controls (1303.7+/-618.0 vs 696.2+/-300.5, p<0.01). However, there was no significant difference between SCLC and NSCLC groups. This result showed that serum level of IGF-I/IGFBPs may be useful markers for diagnosing and identifying tumor types in lung cancer and further studies are needed.