Browsing by Author "Cardenas, H"

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    Basic aspects of oviduct function
    (PARTHENON PUBLISHING GROUP LTD, 1997) Croxatto, HB; Ortiz, ME; Villalon, M; Cardenas, H; Imarai, M; Hermoso, M; Velasquez, L; Orihuela, P; Coutifaris, C; Mastroianni, L
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    PAF receptor and PAF acetylhydrolase expression in the endosalpinx of the human Fallopian tube: possible role of embryo-derived PAF in the control of embryo transport to the uterus
    (2001) Velasquez, LA; Maisey, K; Fernandez, R; Valdes, D; Cardenas, H; Imarai, M; Delgado, J; Aguilera, J
    BACKGROUND: Prostaglandin-E-2 and platelet-activating factor (PAF) are embryonic-derived signals that time embryo passage into the uterus in the mare and hamster respectively. PAF-like activity is detectable in the spent media of preimplantation human embryos and it has been suggested that PAF may be the embryonic signal that controls embryo transport to the uterus in our species. The actions of PAF are regulated at the level of its synthesis and degradation as well as the expression of a specific cell surface receptor (PAFr). The enzyme PAF acetylhydrolase (PAF-AH) degrades PAR This study was undertaken to examine whether or not PAFr and PAF-AH are expressed in the human Fallopian tube and to identify the cell types in which they are expressed. METHODS: The presence of PAFr mRNA in tissue extracts was investigated using reverse transcription-polymerase chain reaction. We amplified the predicted amplicon for PAFr mRNA from RNA samples extracted from Fallopian tubes. The expression of PAF-AH was detected by Western blot and the localization of PAFr and PAF-AH proteins was detected by immunohistochemistry. RESULTS: Utilizing antibodies against PAFr and PAF-AH, co-localization of the two proteins in the epithelium and stromal cells were demonstrated. CONCLUSIONS: These observations show that the human Fallopian tube expresses PAFr and PAF-AH at a location compatible with the proposed paracrine role of early embryo-derived PAF.
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    There a mucosal immune system associated with the mammalian oviduct?
    (1998) Cardenas, H; Corvalan, L; Imarai, M
    The oviduct is a key component of the reproductive system where essential stages such as spermatozoa capacitation, fertilization and early embryo development rake place. Recently, an additional role for the entire female reproductive tract has emerged with important implications for our understanding and management of reproductive health, namely, its role in mounting local immune responses against microbial pathogens. Most of the evidence about mucosal immune responses in the female reproductive tract is related to the vagina, with less information available for the uterus. The less known segment in this regard is the oviduct, which prompted us to review and summarize the current state of knowledge on the immune system at the level of the mammalian oviduct. A comprehensive search was conducted in Medline ann -for the last two years-also in Current Contents. Results demonstrate that the mammalian oviduct is endowed with many of the elements that characterize a mucosal immune system. However, there are gaps in our knowledge that, in addition to important interspecies differences, make it essential to explore further some fundamental questions regarding this system.
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    Variability of breast sucking, associated milk transfer and the duration of lactational amenorrhoea
    (1999) Prieto, CR; Cardenas, H; Croxatto, HB
    Quantitative relationships between physical parameters of sucking, milk transfer and the duration of amenorrhoea were examined in normal mother-baby pairs under exclusive breastfeeding. Sucking pressures were recorded twice on the second and once on the fifth month after birth, during complete breastfeeding episodes, by means of a catheter attached to the nipple and connected to a pressure transducer, the signals of which were analysed by computer. Babies were weighed before and after each sucking episode to estimate milk transfer. In the first nursing episode after noon, 2-month-old babies sucked from 140 to > 800 times during 4-15 min from the first breast, obtaining from 20 to > 100 g milk. The physical parameters of sucking and milk transfer exhibited high inter-individual but low intra-individual variabilities. There were significant differences in the physical parameters of sucking and-milk transfer efficiency between first and second breast and between the second and fifth months after birth. Milk transfer efficiency was inversely correlated with time occupied by non-sucking pauses greater than or equal to 1.5 s, and was directly correlated with mean intersuck intervals in the first breast and with duration of the sucking episode, number of sucks, mean pressure and area under the pressure curve in the second bl:east. There was no correlation between the physical parameters of sucking and duration of lactational amenorrhoea (n = 62). However, significantly more mothers had amenorrhoea lasting > 180 days among those whose babies spent a longer proportion of the nursing episode in non-sucking pauses greater than or equal to 1.5 s. This finding indicates that sensory stimulation of the nipple produced during a nursing episode by stimuli other than sucking itself may have an important role in sustaining lactational amenorrhoea. It is concluded that nursing episodes have a complex structure that allows the development of a breastfeeding phenotype in each mother-baby pair, exhibiting important inter-individual variability The present analysis does not support the contention that this source of variability accounts for the variability in the duration of lactational amenorrhoea.