Browsing by Author "SALVATIERRA, AM"

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    ENDOCRINE RESPONSE AND OVUM TRANSPORT IN WOMEN TREATED WITH D-TRP6-LUTEINIZING HORMONE-RELEASING HORMONE IN THE POST-OVULATORY PERIOD
    (1982) GUILOFF, E; SALVATIERRA, AM; ORTIZ, ME; CROXATTO, HB
    Possible alterations in ovum transport during increased activity of the hypothalamic-pituitary-ovarian axis were investigated in women. D-Trp6-LHRH, a synthetic peptide with potent gonadotropin-releasing activity, was used to induce a gonadotropin surge and stimulate ovarian steroid secretion in the postovulatory phase. The compound was administered i.m. or i.v. 24, 48 or 72 h following the maximum preovulatory lutropin level in plasma in 7 women. An immediate and pronounced gonadotropin surge accompanied by a moderate increase in the estradiol and progesterone level was obtained in all cases. Ova were recovered from the fallopian tubes in 4 of the 7 women 24 h following treatment. The rate of recovery and the location of ova within the genital tract indicate that the treatment and the resulting endocrine changes failed to accelerate migration of the ova toward the uterus. In comparison with other mammals transport of the ovum in the woman is relatively insensitive to endocrine changes occurring in the postovulatory phase.
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    FOLLICLE-STIMULATING HORMONE-GRANULOSA CELL AXIS INVOLVEMENT IN THE ANTIFOLLICULOTROPHIC EFFECT OF LOW-DOSE MIFEPRISTONE (RU486)
    (OXFORD UNIV PRESS UNITED KINGDOM, 1995) CROXATTO, HB; SALVATIERRA, AM; FUENTEALBA, B; LEIVA, L
    This study was designed to assess the involvement of follicle stimulating hormone (FSH)-granulosa and luteinizing hormone (LH)-theca axes in the antifolliculotrophic effect of mifepristone. Plasma gonadotrophins, including plasma LH bioactivity and pulsatility, oestradiol, testosterone and inhibin concentrations, and follicular growth were monitored in volunteer women treated with placebo or mifepristone in two consecutive cycles. Mifepristone was given either as a single dose of 5 mg (n = 7) when the leading follicle had reached a diameter between 12 and 14 mm, or as a multiple dose of 5 mg/day for 3 days, beginning when the leading follicle had reached a diameter between 14 and 16 mm (n = 5) or between 6 and 11 mm (n = 5), Following the single dose of mifepristone, follicular growth and the accompanying increase in plasma oestradiol were arrested at 12 and 36 h respectively without changes in gonadotrophin or testosterone serum concentrations. The 3 day regimen arrested follicular growth and oestradiol rise and decreased plasma inhibin concentrations when follicles were larger than 12 mm at the onset of treatment. These results indicate that the antifolliculotrophic action of mifepristone is associated with a selective compromise of the FSH-granulosa axis of dominant follicles that have passed a critical stage of growth.
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    POST-OVULATORY AGING OF HUMAN OVA .1. LIGHT MICROSCOPIC OBSERVATIONS
    (1982) ORTIZ, ME; SALVATIERRA, AM; LOPEZ, J; FERNANDEZ, E; CROXATTO, HB
    The morphologic changes undergone by the human secondary oocyte following ovulation were assessed by light microscopy in 57 specimens recovered from the Fallopian tube and endometrial cavity between 24 and 144 h after the luteinizing hormone [LH] peak in plasma. Ova recovered shortly after ovulation were surrounded by a large cumulus mass comprising .apprx. 20,000 follicular cells. Whenever it was possible to perform a detailed observation of the perivitelline space in these ova, the presence of a polar body was recognized. The oocyte usually occupied an excentric position within the cumulus. Ovum denudation appeared to proceed by breakdown of the cumulus into fragments and release of the oocyte with a small number of cells attached to the zona. As a consequence of this process, the oocyte, surrounded by a few layers of the cells, frequently coexisted with large fragments of the cumulus. Progress of ovum denudation was time dependent and proceeded at a relatively slow pace. Some uterine ova still had cells attached to the zona. At 96 h after the LH peak 40% of the ova underwent fragmentation of the cytoplasm giving rise to anucleated pieces of varying sizes. The dimensions of the zona pellucida and ooplasm presented wide individual variations as well as some time related changes. The mean external diameter of the zona .+-. SD of 43 ova was 161.6 .+-. 14.6 .mu.m. The occurrence of denudation and cytoplasmic fragmentation were more clearly related to the postovulatory age of the ovum than to the site of recovery. The rate of denudation of human oocytes seems to proceed at a much lower speed in comparison with small mammals currently used as laboratory animals.
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    RELATIVE CONTRIBUTIONS OF ANOVULATION AND LUTEAL PHASE DEFECT TO THE REDUCED PREGNANCY RATE OF BREAST-FEEDING WOMEN
    (1992) DIAZ, S; CARDENAS, H; BRANDEIS, A; MIRANDA, P; SALVATIERRA, AM; CROXATTO, HB
    Objective: To evaluate the contribution of anovulation and luteal phase defects to lactational infertility.
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    SERUM OSTEOCALCIN IN NORMAL MENSTRUAL-CYCLE
    (1992) MORENO, JML; GONZALEZ, G; CAMPINO, C; SALVATIERRA, AM; CROXATTO, HB
    Serum osteocalcin (OC) was serially measured along an ovulatory menstrual cycle in 4 healthy unmedicated volunteers (age 33-38 years). During the study the women maintained their normal diet and daily physical activity. Starting at days 4-5 of the cycle, blood samples were taken between 09-11 AM every 2 or 3 days for OC, FSH, LH, E2 and P determinations. Daily ultrasound assessment of ovulation was performed in all subjects between days 7-18 of the cycle. Hormone determinations and OC were performed by RIA. While blood levels of FSH, LH, E2 and P changed during the cycle, according to the expected ovulatory pattern, serum OC concentrations remained stable during the cycle in each subject. In conclusion, serum OC is independent of the gonadotropin and ovarian steroid variations during the normal menstrual cycle.