Browsing by Author "Germain, AM"
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- ItemA high-fat diet induces and red wine counteracts endothelial dysfunction in human volunteers(2000) Cuevas, AM; Guasch, V; Castillo, O; Irribarra, V; Mizon, C; San Martin, A; Strobel, P; Perez, D; Germain, AM; Leighton, FEndothelial dysfunction is associated with atherogenesis and oxidative stress in humans. In rat and rabbit blood vessels, wine polyphenol antioxidants induce vascular relaxation in vitro through the NO-cCMP pathway. To assess the effect of a regular high-fat diet (HFD) and moderate red wine consumption on endothelial function (EF), a study was performed in healthy male volunteers. EF was measured as flow-mediated dilatation of the brachial artery, employing high-resolution ultrasound after an overnight fast. Other clinical and biochemical parameters related to EF were also measured. Six volunteers received a control diet, rich in fruits and vegetables (27% calories as fat) and five volunteers received an HFD (39.5% calories as fat). Measurements were done twice on each volunteer: after a period of 30 d with diet plus 240 mt of red wine/d, and after a period of 30 d with diet, without wine. In the absence of wine, there is a reduction of EF with HFD when compared to the control diet (P = 0.014). This loss of EF is not seen when both diets are supplemented with wine for 30 d (P = 0.001). Plasma levels of n-3 fatty acids (R-2 = 0.232, P = 0.023) and lycopene (R-2 = 0.223, P = 0.020) show a positive correlation with individual EF measurements, but they do not account for the significant differences observed among dietary groups or after wine supplementation. These results help elucidate the deleterious effect of a high-fat diet and the protective role of wine, n-3 fatty acids and dietary antioxidants in cardiovascular disease.
- ItemBile acids increase response and expression of human myometrial oxytocin receptor(MOSBY, INC, 2003) Germain, AM; Kato, S; Carvajal, JA; Valenzuela, GJ; Valdes, GL; Glasinovic, JCOBJECTIVE: We tested the hypothesis that during intrahepatic cholestasis of pregnancy bile acids activate the myometrial oxytocin receptor pathway.
- ItemDistribution of angiotensin-(1-7) and ACE2 in human placentas of normal and pathological pregnancies(W B SAUNDERS CO LTD, 2006) Valdes, G; Neves, LAA; Anton, L; Corthorn, J; Chacon, C; Germain, AM; Merrill, DC; Ferrario, CM; Sarao, R; Penninger, J; Brosnihan, KBThis work was designed to study the expression of the vasodilator peptide angiotensin-(1-7) [Ang-(1-7)] and its generating enzyme (ACE2) in the uteroplacental interface. Placentas were obtained from 11 early pregnancy failures (5 miscarriages and 6 ectopic pregnancies), 15 normotensive, and 10 preeclamptic gestations. In placental villi, the main sites of immunocytochemical expression of Ang-(1-7) and ACE2 were the syncytiotrophoblast, cytotrophoblast, endothelium and vascular smooth muscle of primary and secondary villi. Syncitial Ang-(1-7) expression in samples obtained from miscarriages and ectopic pregnancies was increased compared to normal term pregnancy [2.0 (2.0-2.25 for the 25 and 75% interquartile range) vs 1.3 (1.0-1.9), p < 0.01]. In the maternal stroma, Ang-(1-7) and ACE2 were expressed in the invading and intravascular trophoblast and in decidual cells in all 3 groups. Ang-(1-7) and ACE2 staining was also found in arterial and venous endothelium and smooth muscle of the umbilical cord. The expression of Ang-(1-7) and ACE2 was similar in samples obtained from normal term or preeclamptic pregnancies, except for increased expression of ACE2 in umbilical arterial endothelium in preeclarmpsia [0.5 (0.5-0.8) vs 0.0 (0.0-0.0), p < 0.01]. The uteroplacental location of Ang-(1-7) and ACE2 in pregnancy suggests an autocrine function of Ang-(1-7) in the vasoactive regulation that characterizes placentation and established pregnancy. (c) 2005 Elsevier Ltd. All rights reserved.
- ItemPreterm labor: Placental pathology and clinical correlation(LIPPINCOTT WILLIAMS & WILKINS, 1999) Germain, AM; Carvajal, J; Sanchez, M; Valenzuela, GJ; Tsunekawa, H; Chuaqui, BObjective: To determine the relevance of ischemia in the incidence of preterm labor. A second objective was to document perinatal outcomes for patients with preterm labor classified according to its clinical, functional, and pathologic characteristics (infectious, ischemic, mixed, or idiopathic).
- ItemTissue kallikrein and bradykinin B2 receptor in human uterus in luteal phase and in early and late gestation(2001) Valdés, G; Germain, AM; Corthorn, J; Chacón, C; Figueroa, CD; Müller-Esterl, WThis study was addressed to evaluate the temporo-spatial pattern of key components of the kallikrein-kinin system in human uterus in luteal phase (n = 7), early pregnancy (isolated spontaneous abortions, n = 11; ectopic pregnancies, n = 9), idiopathic preterm deliveries (n = 5), and term gestations (n = 12). Tissue kallikrein mRNA and protein and the type 2 bradykinin receptor (B2R) protein were expressed in luminal and glandular epithelium and in endothelial cells of stromal and myometrial blood vessels, while tissue kallikrein mRNA and B2R, but not tissue kallikrein protein, were observed in decidual cells and in arteriolar and myometrial muscle. A greater signal intensity for tissue kallikrein mRNA and protein and of B2R protein was observed in the early pregnancy samples. The sites and variations of the tissue kallikrein mRNA and protein and of the B2R protein in the human uterus and in fallopian tubes during the luteal phase and in pregnancy coincide with those described for other vasoactive effectors such as nitric oxide, prostacyclins, growth factors, and renin. The uterine localization of the main enzyme and receptor of the tissue kallikrein-kinin system in key sites for embryo attachment, implantation, placentation, maintenance of placental blood flow, and parturition supports the notion that the kallikrein-kinin system participates in these processes, probably through vasodilation, increased vasopermeability, enhanced matrix degradation, stimulation of cell proliferation, and myometrial contractility.
- ItemTissue kallikrein in human placenta in early and late gestation(2001) Valdés, G; Chacón, C; Corthorn, J; Figueroa, CD; Germain, AMThis study was addressed to identify kallikrein mRNA and protein in early, preterm, and term human placenta and to evaluate their temporospatial pattern. Kallikrein mRNA was expressed in syncytio/cytotrophoblasts and in the endothelial cells of the floating villi, with a greater intensity in early samples (isolated spontaneous abortions and ectopic pregnancies). Cytotrophoblasts at the base of the anchoring villi, maternal decidua and decidual arteries, endothelial cells of chorionic and basal plate blood vessels, and the amniotic epithelium presented a positive signal. Tissue kallikrein was predominantly observed in syncytiotrophoblasts and had a greater immunoreactivity in first-trimester samples. Intraarterial trophoblasts, blood vessels of the floating villi, basal and chorionic plates, and the amniotic epithelium showed positive immunoreactivity. The sites and variations of the tissue kallikrein mRNA and protein in the human placenta, in different stages of pregnancy, support the hypothesis that this enzyme may participate in the establishment and maintenance of placental blood flow through vasodilation, platelet antiaggregation, cell proliferation, and trophoblast invasion.
- ItemTwenty-four-hour pattern of cortisol in the human fetus at term(2001) Serón-Ferré, M; Riffo, R; Valenzuela, GJ; Germain, AMOBJECTIVES: Indirect evidence suggests that adrenal steroid production in the human fetus may have a circadian rhythm. To assess whether there is a 24-hour rhythm of fetal cortisol in the human fetus, we investigated the relationship between fetal and maternal cortisol and cortisone concentrations in maternal, umbilical arterial, and umbilical venous blood samples over a 24-hour period.
- ItemUrinary kallikrein excretion in the human menstrual cycle, normal pregnancy and lactation(PARTHENON PUBLISHING GROUP, 1998) Valdes, G; Corthorn, J; Oyarzun, E; Berrios, C; Foradori, A; Germain, AM; Villarroel, LObjectives To evaluate the temporal pattern of active and total urinary kallikrein excretion during the menstrual cycle, pregnancy and lactation, and to associate changes in kallikrein excretion with those of ovarian and placental hormones.