Browsing by Author "ORTIZ, ME"
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- ItemATTEMPTS TO MODIFY OVUM TRANSPORT IN WOMEN(1979) CROXATTO, HB; ORTIZ, ME; DIAZ, S; HESS, R
- ItemCORRELATION BETWEEN HISTOLOGIC DATING OF HUMAN CORPUS-LUTEUM AND THE LUTEINIZING-HORMONE PEAK-BIOPSY INTERVAL(1980) CROXATTO, HD; ORTIZ, ME; CROXATTO, HBThe accuracy of retrospective dating of ovulation in women based on the histologic dating of the corpus luteum was assessed. Corpora lutea enucleated from the ovary of 39 women from 1-6 days following the luteinizing hormone [LH] peak in plasma were examined by routine histologic techniques and dated according to Corner''s criteria. The correlation between the LH peak-biopsy interval and histologic dating was assessed. Linear regression analysis of the data gave a correlation coefficient of 0.76. The dating of different corpora lutea obtained at the same LH peak-biopsy interval can differ by as much as 4 days. The stages named by Corner as days 1 and 2 seem to develop within the first 24 h following the LH peak, while stages corresponding to days 4 and 5 each take 2 days to develop. The use of corpus luteum morphologic features for retrospective timing of ovulation is evidently subject to an error of variable magnitude due to unequal duration of each stage, and considerable individual variation.
- ItemDIFFERENTIAL TRANSPORT OF FERTILIZED AND UNFERTILIZED OVA IN PSEUDOPREGNANT RATS(SOC BIOL CHILE, 1979) VILLALON, M; ORTIZ, ME; AGUAYO, C; MUNOZ, J; CROXATTO, HB
- ItemDIFFERENTIAL TRANSPORT OF FERTILIZED AND UNFERTILIZED OVA IN THE RAT(SOC STUDY REPRODUCTION, 1982) VILLALON, M; ORTIZ, ME; AGUAYO, C; MUNOZ, J; CROXATTO, HB
- ItemEFFECT OF ESTRADIOL 3-BENZOATE AND ESTRADIOL 3,17BETA ON OVUM TRANSPORT IN RATS(ASSN LATINOAMER CIENC FISIOL, 1975) ORTIZ, ME; VILLALON, M; ALONSO, ML; CROXATTO, HB
- ItemEMBRYOS OF DIFFERENT AGES TRANSFERRED TO THE RAT OVIDUCT ENTER THE UTERUS AT DIFFERENT TIMES(1989) ORTIZ, ME; LLADOS, C; CROXATTO, HBIndirect evidence of embryo signalling to the oviduct was sought in rats by examining the transport of embryos of different ages. One-cell or four-cell embryos were transferred to the oviducts of recipient rats on Day 1 of pregnancy, and the number, condition, and location of native and transferred embryos was assessed on Day 4. To control for effect of the presence of foreign embryos and excess number of eggs and the transfer procedure upon the fate of native embryos, other groups of rats were sham-operated or left undistributed. Recipients had a mean number of ova significantly higher than controls. In controls and recipients of 1-cell embryos, the majority of eggs reached the morula stage and all of them were located in the oviducts. In those animals receiving 4-cell embryos, half of the eggs had reached the blastocyst stage and 28% were in the uteri (p < 0.005). These results support the idea that advanced embryos can influence the timing of their entrace to the uterus in rats.
- ItemENDOCRINE 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, HBPossible 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.
- ItemFERTILIZED AND UNFERTILIZED OVA ARE TRANSPORTED AT DIFFERENT RATES BY THE HAMSTER OVIDUCT(1986) ORTIZ, ME; BEDREGAL, P; CARVAJAL, MI; CROXATTO, HBTo determine if the egg provides any clues for the regulation of ovum transport in the hamster, oocyte and embryo transport were compared. On the evening preceeding ovulation, the animals were randomly assigned to one of five groups. They were caged overnight with a male of proven fertility (Group 1) or they were isolated (Group 2). Other females were artificially inseminated in both uterine horns at 2200 h either with fertile epididymal spermatozoa (Group 3), spermatozoa rendered infertile by freezing the thawing (Group 4), or with fertile spermatozoa in one uterine horn and infertile spermatozoa in the contralateral horn (Group 5). The number, condition, and distribution of ova in the genital tract were assessed at various intervals during the next 4 days. The rate of fertilization and normal development in females or sides inseminated with fertile or infertile spermatozoa was over 90% and 0% respectively. Embryos in Groups 1 and 3 reached the uterus 1 day earlier than unfertilized oocytes in Groups 2 and 4. In group 5, the transport of embryos resulting from insemination with fertile spermatozoa followed a pattern similar to those in Groups 1 and 3; the oocytes in the contralateral tract resembled those of Groups 2 and 4. The different transport rates of embryos and oocytes were not associated with the reproductive state of the female but with the condition of the ova. Moreover, the different transport rates were observed in animals transporting the two types of eggs simultaneously on different sides indicating that there is a local recognition of some unidentified factor unequally present in fertilized and unfertilized eggs.
- ItemHIGH POTASSIUM CONCENTRATION IMPROVES THE RATE OF ACROSOME REACTION IN HUMAN-SPERMATOZOA(1988) ROBLERO, L; FERNANDEZ, E; GUADARRAMA, A; ZEGERSHOCHSCHILD, F; ORTIZ, MEProgressively motile spermatozoa recovered by swim-up method from semen of two fertile men were inoculated for 24 hours in culture media containing either 4.7, 15, or 25 mM of potassium (K). Aliquots of each culture condition were obtained at 0, 1, 5, 10, and 24 hours of incubation for the assessment of progressive motility, percentage of dead spermatozoa, and percentage of acrosome reaction (AR), as measured by triple-stain technique. A total of ten experiments including each K concentration were analyzed. The results of this study showed no effect of K concentration on the percentage of progressively motile spermatozoa, irrespective of the time of incubation. The percentage of live spermatozoa was significantly greater in culture medium containing 25 mM K (P < 0.05). There was a greater percentage of reacted spermatozoa with 25 mM K, as compared with 4.7 and 15 mM (P < 0.05). Furthermore, the time taken to acheive 20% of AR was 2 hours at 25 mM K compared with 10.9 hours at 4.7 mM K.
- ItemIMPORTANCE OF UTERINE EXPULSION OF EMBRYOS IN THE INTERCEPTIVE MECHANISM OF POSTCOITAL ESTRADIOL IN RATS(1991) ORTIZ, ME; BASTIAS, G; DARRIGRANDE, O; CROXATTO, HBThis study compares the interceptive effectiveness of 1-mu-g oestradiol given as a single s.c. injection at 0900 or 1700 hours on Day 1, 2, 3, or 4 of pregnancy in rats. Increasing the interval from ovulation to treatment accelerated the oviducal transport of a larger number of embryos, the majority of which were lost from the genital tract. However, after treatment at 1700 hours on Day 3 the majority of accelerated embryos were retained in the uterus. The number of implanted embryos on Day 14 was equal to the number of eggs remaining in the tract 24 h after treatment. As a consequence, the highest interceptive effectiveness was obtained with treatment given at 1700 hours on Day 2 and at 0900 hours on Day 3 of pregnancy. Accelerated oviducal transport and uterine expulsion of embryos begin to dissociate after Day 2 of pregnancy in the rat. This explains why the most effective treatments to accelerate oviducal transport are not always the most effective to reduce the number of implantations. These data emphasize the importance of retentive and expulsive properties of the uterus for fertility and infertility.
- ItemOVUM TRANSPORT AND FERTILITY FOLLOWING POST-OVULATORY TREATMENT WITH ESTRADIOL IN RATS(SOC STUDY REPRODUCTION, 1979) ORTIZ, ME; VILLALON, M; CROXATTO, HB
- ItemPOST-OVULATORY AGING OF HUMAN OVA .1. LIGHT MICROSCOPIC OBSERVATIONS(1982) ORTIZ, ME; SALVATIERRA, AM; LOPEZ, J; FERNANDEZ, E; CROXATTO, HBThe 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.
- ItemSPERM MIGRATION THROUGH THE FEMALE GENITAL-TRACT OF THE NEW-WORLD MONKEY CEBUS-APELLA(1995) ORTIZ, ME; GAJARDO, G; LEON, CG; HERRERA, E; VALDEZ, E; CROXATTO, HBThis study was designed to characterize sperm migration in the female genital tract of Cebus apella. Forty-eight cycles of eighteen females mated during the periovulatory period were studied. Eggs were searched for and spermatozoa were counted in segmental flushings of the genital tract performed in situ 1-7 h, 19-31 h, or 45-56 h after coitus. Of 14 eggs recovered, 8 were fertilized, thus assuring a reasonable normality of prefertilization phenomena in both males and females.
- ItemUTERINE KALLIKREIN IN THE EARLY PREGNANT RAT(OXFORD UNIV PRESS INC, 1993) VALDES, G; CORTHORN, J; SCICLI, AG; GAETE, V; SOTO, J; ORTIZ, ME; FORADORI, A; SAED, GMUterine homogenates of cycling and early pregnant Sprague Dawley rats and purified rat urinary kallikrein showed similar curves of displacement of I-125-kallikrein binding to a polyclonal antibody. Uterine kallikrein concentration measured by RIA was 8.7 +/- 2 SEM ng/g wet weight during the cycle (n = 6 in diestrus and metestrus) and 20.8 +/- 2 SEM (n = 7) ng/g wet weight on Day 7 of pregnancy (P7) (p < 0.001). On P7, kallikrein concentration was increased 12.4-fold in the implantation nodes, as compared to the interimplantation segments. Uterine homogenates of rats on P7, submitted to DEAE-cellulose chromatography and Sephadex gel filtration, yielded two fractions containing kallikrein immunoreactivity and kininogenase activity, with molecular masses that ranged from 120-125 kDa and 39-43 kDa, respectively. In the RIA, both fractions displayed parallelism with purified kallikrein. Enzymatic activity was expressed after activation by trypsin. It was inhibited by aprotinin, PMSF, p-amino-benzamidine, and leupeptin, but not by soybean or ovomucoid trypsin inhibitors. Kallikrein mRNA was demonstrated by reverse transcriptase/polymerase chain reaction in uteri of nonpregnant and P7 rats. These results show that rat uterus synthesizes one or more serine proteases that are immunologically and enzymatically related to tissue kallikrein. The increase of kallikrein in the implantation node on P7-determined both by an increment of whole uterus kallikrein content and a depletion of the interimplantation segments-suggests that kallikrein may play a role in the vasoactive changes of implantation.