Browsing by Author "Guerra, Irene"

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    Endothelial dysfunction - A link among preeclampsia, recurrent pregnancy loss, and future cardiovascular events?
    (LIPPINCOTT WILLIAMS & WILKINS, 2007) Germain, Alfredo M.; Romanik, Mary Carmen; Guerra, Irene; Solari, Sandra; Soledad Reyes, Maria; Johnson, Richard J.; Price, Karen; Karumanchi, S. Ananth; Valdes, Gloria
    We tested the hypothesis that endothelial dysfunction could cause placentation-related defects, persist after the complicated pregnancy, and probably cause cardiovascular disease later in life. Brachial arterial reactivity and factors related to endothelial dysfunction, such as circulating cholesterol, uric acid, nitrites, L-arginine, asymmetrical dimethylarginine, vascular endothelial growth factor, and soluble vascular endothelial growth factor receptor-1, in women with previous healthy pregnancies (n = 22), patients with severe preeclampsia (n = 25), or patients with recurrent pregnancy loss (n = 29), at day 10 of the luteal phase of an ovulatory cycle an average of 11 to 27 months after pregnancy were evaluated. Both groups with placentation defects had a significant decrease in endothelium-dependent dilatation, a higher rate of endothelial dysfunction, lower serum nitrites, and higher cholesterol as compared with control subjects; subjects with previous preeclampsia additionally had higher normal blood pressures and a greater parental prevalence of cardiovascular disease. Patients with recurrent pregnancy loss also demonstrated a significantly lower endothelium-independent vasodilatation. A trend to an inverse correlation was found between serum cholesterol serum and endothelial-mediated vasodilatation in the whole study population. Uric acid, L-arginine, asymmetrical dimethylarginine, vascular endothelial growth factor, and soluble vascular endothelial growth factor receptor-1 were similar in all of the groups. We postulate that endothelial dysfunction may represent a link between preeclampsia and increased cardiovascular disease latter in life and propose that women with unexplained recurrent miscarriages are also at increased cardiovascular risk. The identification and correction of endothelial dysfunction detected during the reproductive stage on obstetric outcome and on cardiovascular diseases needs to be elucidated.
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    Phenotype and genotype of thiopurine methyltransferase in Chilean individuals
    (SOC MEDICA SANTIAGO, 2012) Jorquera, Andres; Solari, Sandra; Vollrath, Valeska; Guerra, Irene; Chianale, Jose; Cofre, Colomba; Kalergis, Alexis; Ibanez, Patricio; Bueno, Susan; Alvarez Lobos, Manuel
    Background: Thiopurines (azathioprine and 6-mercaptopurine) are highly effective medications but with potential adverse effects. Thiopurine methyltransferase (TMPT) is the key enzyme in their pharmacokinetics and is genetically regulated. A low activity of TPMT is associated with myelotoxicity. The genotype and enzyme activity can vary by ethnicity. Aim: To study the activity and genotype of TPMT in a group of Chilean subjects. Material and Methods: In 200 healthy adult blood donors, TPMT activity was determined by high performance liquid chromatography (HPLC). Deficient, low, normal or high levels were defined when enzymatic activity was <= 5, 6-24, 25-55 and >= 56 nmol/grHb/h, respectively. Genotyping of TPMT ((star)1, (star)2, (star)3A, (star)3B, (star)3C) was performed by PCR. Results: Seventy seven women (38.5%) and 123 men (61.5%), with an average age of 34.9 years were studied. Eighteen subjects (9%) had a low enzymatic activity, 178 (89%) had normal activity, 4 (2%) had high activity and no genotype deficient subjects were identified. The wild type genotype ((star)1) was found in 184 (92%) individuals and 16 (8%) were heterozygous for the variants: (star)2 (n = 2), (star)3A (n = 13) and (star)3C (n = 1). No homozygous subjects for these variants were identified. Wild type genotype had an increased enzymatic activity (40.8 +/- 7.2 nmol/gHb/h) compared to heterozygous group (21.2 +/- 3 nmol/gHb/h; p < 0.001). Conclusions: Less than 10% of a Chilean population sample has a low enzymatic activity or allelic variants in the TPMT gene, supporting the use of thiopurines according to international recommendations. (Rev Med Chile 2012; 140: 889-895).