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A Guadarrama

Publications and source records attributed to A Guadarrama.

6 recordsLinked to original sources
PubMed1996

Effect of copper ion on the motility, viability, acrosome reaction and fertilizing capacity of human spermatozoa in vitro.

The objective of this study is to provide additional information on the effect of copper ion (Cu2+) in preventing pregnancy. Human spermatozoa, selected by the swim-up method, were incubated for 0, 5 or 24 h in the presence of 10 ng, 1 microgram, 10 micrograms or 100 micrograms of Cu2+ mL-1 in BWW culture medium, and then evaluated in terms of their motility, viability, acrosome reaction (AR) and the capacity to penetrate zona-free hamster eggs. AR and penetration in zona-free hamster eggs were assessed at 5 h of incubation. Motility, viability and AR in sperm incubated for 5 h were significantly affected by Cu2+ at a concentration of 100 micrograms mL-1, but not at the lower concentrations. Incubation for 24 h did not affect motility and viability of sperm incubated in the presence of concentrations of Cu2+ ranging from 10 ng mL-1 to 10 micrograms mL-1, but a concentration of 100 micrograms mL-1 caused a significant decrease in both parameters. In contrast, the penetration rate of zona-free hamster oocytes significantly decreased compared with that of controls, when only sperm were incubated in the presence of concentrations of Cu2+ ranging from 10 ng mL-1 to 10 micrograms mL-1, and no penetration was observed in the presence of 100 micrograms mL-1 of Cu2+ . When only oocytes were exposed to Cu2+, the penetration rate dropped to 50% of that of the controls. Finally, when both gametes were exposed to Cu2+ before co-incubation, the penetration rate fell to zero for every concentration tested. Results showed that copper, at concentrations similar to those released from intrauterine devices (IUD), affects the fertilizing capacity of human gametes in vitro and interferes with the sperm-oocyte interaction leading to fertilization. These effects suggest that the principle action of Cu2+ released from Cu-IUD is to act as a preconception contraceptive agent when delivered in endometrial and oviducal fluids.

Acrosome↗
PubMed1992

Pregnancy rate in an oocyte donation program.

Oocyte donation programs offer an alternative treatment for infertile women with ovarian failure or abnormal ovarian function. Seventeen cycles of in vitro fertilization and embryo transfer with donated oocytes were performed in 13 women, with a mean age of 34.8 years. The hormonal replacement therapy consisted of a fixed dose of oral estradiol valerate, 6 mg daily, and intramuscular progesterone in oil, 100 mg daily. Estrogen and progesterone were continued for 10 more weeks after embryo transfer if pregnancy was established. After 13 embryo transfers, 8 pregnancies were obtained, for a pregnancy rate per transfer of 61.5%. Today seven pregnancies are progressing normally, including one set of twins. This results suggest that an oocyte donation program using a fixed and simple hormonal replacement therapy is an adequate treatment for these infertile couples.

Adult↗
PubMed1990

High potassium concentration and the cumulus corona oocyte complex stimulate the fertilizing capacity of human spermatozoa.

Progressively motile spermatozoa were incubated for 24 hours in culture media containing 4.7 or 25 mM K, in the presence or absence of hamster cumulus oophorus. The percentage of spermatozoa with progressive motility was significantly higher at 24 hours in the presence of cumulus corona oocyte complexes, irrespective of K concentration. A significant decrease in sperm mortality was observed with the association of 25 mM K and cumulus cells. A higher percentage of acrosome reaction was observed in spermatozoa incubated in 25 mM K when compared with 4.7 mM K, irrespective of time and the presence or absence of cumulus. The percentage of penetrated oocytes at 2 and 5 hours of incubation was higher when sperm had been incubated in 25 mM K than in 4.7 mM K. The presence of cumulus in the culture medium induced an additional significant increase in the percentage of penetrated oocyte. Although at 24 hours of incubation the percentage of acrosome reaction was higher than at 2 and 5 hours, the percentage of penetrated oocytes did not increase proportionally.

Acrosome↗
PubMed1988

High potassium concentration improves the rate of acrosome reaction in human spermatozoa.

Progressively motile spermatozoa recovered by swim-up method from semen of two fertile men were incubated 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 less than 0.05). There was a greater percentage of reacted spermatozoa with 25 mM K, as compared with 4.7 and 15 mM (P less than 0.05). Furthermore, the time taken to achieve 20% of AR was 2 hours at 25 mM K compared with 10.9 hours at 4.7 mM K.

Acrosome↗