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PubMed1999

Effects of porcine follicular fluid and oviduct-conditioned media on maturation and fertilization of porcine oocytes in vitro.

Advances in porcine in vitro fertilization have been impaired by low normal fertilization rates resulting from a high rate of polyspermy. The present study was undertaken to determine the effects of porcine follicular fluid (pFF) and oviductal explant-conditioned medium on maturation and fertilization of porcine oocytes in vitro. Oocytes and pFF were collected from small, medium, and large follicles and pooled within size category. Maturation and fertilization media were supplemented (10%) with either fetal calf serum (FCS) or pFF (either fresh or snap-frozen). Snap-frozen pFF from small (3.1-5.0 mm) and medium (5.1-7 mm) follicles, respectively, increased maturation rates of oocytes from small and medium follicles by nearly 36% (p < 0.05) compared with those treated with FCS or fresh pFF. Supplementing media with either fresh or snap-frozen pFF from medium follicles reduced (p < 0.05) polyspermy of oocytes from small follicles by 30% compared with supplemental FCS. Snap-frozen pFF increased (p < 0.05) normal fertilization compared to that in fresh pFF (29% vs. 18%). Supplementing oocytes from medium follicles with snap-frozen pFF yielded the lowest (18%, p < 0.05) polyspermy rate. Oocytes from both small and medium follicles supplemented with pFF and/or conditioned medium (CM) from oviducts of periovulatory gilts exhibited a 95% improvement in normal fertilization rate and a 34% decrease in polyspermy rate compared to those treated with FCS (p < 0.05). CM from oviducts of luteal gilts did not improve rates of polyspermy and normal fertilization (p > 0.05). We conclude that snap-frozen follicular fluid from medium follicles and CM from cultured oviducts of periovulatory gilts improve in vitro maturation, reduce polyspermy, and increase normal fertilization rates in vitro.

Animals↗
PubMed1999

Isoforms of the inositol 1,4,5-trisphosphate receptor are expressed in bovine oocytes and ovaries: the type-1 isoform is down-regulated by fertilization and by injection of adenophostin A.

Mammalian fertilization is characterized by the presence of long-lasting intracellular calcium ([Ca2+]i) oscillations that are required to induce oocyte activation. One of the Ca2+ channels that may mediate this Ca2+ release is the inositol 1,4, 5-trisphosphate receptor (IP(3)R). Three isoforms of the receptor have been described, but their expression in oocytes and possible roles in mammalian fertilization are not well known. Using isoform-specific antibodies against IP(3)R types 1, 2, and 3 and Western analysis, we determined the isoforms that are expressed in bovine metaphase II oocytes and ovaries. In oocytes, all isoforms are expressed, but type 1 is present in overwhelmingly larger amounts and is likely responsible for the majority of Ca2+ release at fertilization. In ovarian microsomes, all three isoforms appear well expressed, suggesting the participation of all IP(3)R isoforms in ovarian Ca2+ signaling. We then investigated whether the reported cessation/reduction in amplitude of fertilization-associated [Ca2+]i oscillations, which is observed as pronuclear formation approaches, corresponded with down-regulation of the IP(3)R-1 isoform. Fertilization resulted in approximately 40% reduction in the amount of receptor by 16 h postinsemination. In addition, injection of adenophostin A, a potent IP(3)R agonist that elicits high-frequency [Ca2+]i oscillations in mammalian oocytes, induced similar reduction in receptor numbers. Together, these data show that 1) the three IP(3)R isoforms are expressed in bovine oocytes; 2) IP(3)R-1 is likely to mediate most of the Ca2+ release during fertilization; 3) its down-regulation may explain the decline in amplitude of sperm-induced [Ca2+]i rises as fertilization progresses toward pronuclear formation; and 4) agonists of the IP(3)R induce down-regulation of the type-1 receptor in oocytes similar to that evoked by fertilization.

Adenosine↗
PubMed1993

Fertility awareness as a component of sexuality education. Preliminary research findings with adolescents.

Fertility awareness refers to the observation and interpretation of cervical mucus, often called vaginal discharge. A woman's cervical-mucus pattern indicates the time of ovulation and differentiates the fertile and infertile phases of the menstrual cycle from each other. Fertility awareness enables a woman to know when pregnancy can and cannot occur on a daily basis during each menstrual cycle. There has been, to date, almost no exploration of the appropriateness of fertility-awareness instruction for adolescents. A review of the literature on adolescent cognitive development, sexual activity, knowledge of fertility and contraceptive risk-taking behavior is presented. Based on the literature review, a theoretical rationale for fertility-awareness instruction as a unique sex-education curriculum for adolescents is proposed. The content and teaching techniques of a fertility-awareness presentation for teenagers is described. Directions for future research in fertility-awareness instruction for teenagers, and the need for long-term follow-up to assess the effects of such education on teenagers' sexual activity and contraceptive use are discussed.

Adolescent↗
PubMed2005

Has human fertility declined over time?: why we may never know.

BACKGROUND: Reports of decreased semen quality over time have raised concerns about possible reductions in human fertility. Studies of couple fertility have produced conflicting results. We evaluate how changes in the availability and use of effective contraception and induced abortion might bias the direct study of time trends in couple fertility. METHODS: We assess the potential for bias in the context of 2 common study designs: (1) a study of time-to-pregnancy that estimates fecundability (excluding unintended pregnancies) and (2) a study of infertility rates that categorizes couples as fertile or infertile (including couples with unintended pregnancies as fertile). RESULTS: In time-to-pregnancy studies, bias alone could produce more than a 2-fold apparent increase in fecundability over recent decades. In studies of infertility rates, the bias works in the opposite direction: a 30% underestimation of infertility during earlier decades could produce an apparent decrease in fertility over time. CONCLUSIONS: Over the past 5 decades, changes in social factors that affect the rate and fate of unintended pregnancies could substantially bias time trends in fertility. These biases may explain the conflicting reports in the literature. Except in rare settings in which the factors affecting reproductive choices have not changed, it is probably impossible to identify biologic changes in fertility over recent decades.

Abortion, Induced↗
PubMed1981

An assessment of the fertilizing ability of spermatozoa in the epididymis of the marmoset monkey (Callithrix jacchus).

The fertilizing ability of spermatozoa from differ regions of the epididymis of the marmoset monkey, Callithrix jacchus, was assessed by determining their rate of fusion with zonaless hamster ova in vitro. This technique tests for functional competence and was validated using epididymal spermatozoa of the hamster whose fertility have been measured previously by in vivo fertilization experiments. The results suggest that some marmoset spermatozoa first acquire the ability to fertilize in the distal caput and proximal corpus epididymidis although the majority become fertile on reaching the proximal cauda region. Acquisition of fertilizing capacity was associated with a change in the degree and character of sperm motility. However, it is considered that modifications to the sperm plasmalemma which allow capacitation and the acrosome reaction to occur are of primary importance for sperm fertility. The development of sperm fertilizing ability in the marmoset is discussed in relation to that in other primates.

Animals↗
PubMed1982

Fertilization of hamster ova by human spermatozoa in relation to other semen parameters.

Different indices of the zona-free hamster ovum test system were interrelated. High correlations were found between the fertilization percentage and the average number of penetrated spermatozoa/ovum (r = 0.99) and between the fertilization percentage and the number of spermatozoa attached to the ova surfaces (r = 0.72). Fertilization percentages from 63 subfertile patients were correlated with different semen factors assessed by multiple exposure photography (MEP). Low correlations were found between sperm concentration and fertilization percentage (r = 0.29) and between fertilization percentage and motile sperm count (r = 0.33). Spermatozoa progressing with high average velocity had low fertilization rates compared to specimen with moderate average velocity. Effects of sperm washing on the in vitro fertilizing capacity were studied in a group of 40 subfertile men. The fertilization percentages of 8 specimens--with visual seminal plasma abnormalities--increased significantly when immediate dilution of semen was applied.

Animals↗
PubMedDate not supplied

Human sperm movement assessed with the Hamilton-Thorn motility analyzer and in vitro fertilization.

UNLABELLED: The relationship between sperm movement characteristics obtained by computerized analysis and the in vitro fertilization rates of human oocytes was studied. In 144 consecutive in vitro fertilization treatments a sample of prepared semen was analysed by a Hamilton-Thorn Motility Analyzer. In addition a visual estimation of sperm count and motility was made. Significant correlations with the fertilization rate were found for all visual parameters. Of the computerized measurements, the mean velocities of motile spermatozoa and the concentration of motile cells were significantly correlated. The average path velocity correlated best (r = 0.42, P < 0.001). There was no relationship between the percentage of motile sperm showing hyperactivated movement and the fertilization rate. A forward stepwise logistic regression analysis selected the following variables of predictive value for fertilization: average path velocity, male factor infertility as indication for in vitro fertilization, motility and concentration, as measured by the Hamilton-Thorn analyzer. A logistic regression model to predict the cases with low (< 0.2) or high fertilization rates, included the average path velocity as a significant variable and classified the samples with 90% overall accuracy. IN CONCLUSION: movement characteristics of spermatozoa in culture medium, especially the average path velocity are of prognostic value in prediction of human oocyte fertilization rates.

Computers↗
PubMed2005

Effect of the removal of cumulus cells on the nuclear maturation, fertilization and development of porcine oocytes.

The present study was conducted to investigate the effects of attachment of cumulus cells to porcine oocytes during the process of maturation and fertilization on the nuclear maturation, fertilization and subsequent development after in vitro fertilization (IVF). In the first experiment, the cumulus cells were removed from cumulus-oocyte complexes (COCs) at 0, 24 and 42 h after the onset of maturation culture and were then cultured until reaching 42 h of cultivation. In the second experiment, COCs were denuded as described in the first experiment, then fertilized and cultured for 7 days. As a control, cumulus cells were allowed to maintain attachment to the oocytes until the end of IVF. The proportion of oocytes reaching metaphase II significantly increased with the delay in the removal treatment of cumulus cells. The proportion of normal fertilization gradually increased with delay in the removal treatment of cumulus cells from COCs until the end of IVF. However, no significant difference in the proportion of normal fertilization was found between the 42-h and control groups. The removal treatment of cumulus cells in the 0- and 24-h group significantly (p < 0.05) decreased the proportion of cleaved embryos when compared with the control, and none of them developed to the blastocyst stage. The proportion of development to the blastocyst stage was significantly higher (p < 0.05) in the control group than in the 42-h group (18.1% vs 12.4%; p < 0.05). The present study indicates that the attachment of cumulus cells to the oocyte during maturation and fertilization is important to support oocyte nuclear maturation, fertilization and subsequent embryo development. Particularly, the attachment of cumulus cells to the oocyte during IVF promotes embryonic development.

Animals↗
PubMed1994

Effects of human serum supplementation on fertilization and development of mouse embryos.

Serum is generally used as a protein supplement in culture media for human in vitro fertilization (IVF). To determine the effects of serum supplementation on the development of preimplantation embryos, one-cell and two-cell mouse embryos fertilized in vitro and in vivo were cultured in BWW medium supplemented with preovulatory patient serum (PS), human fetal cord serum (HCS), or bovine serum albumin (BSA). The rates of fertilization and development of embryos fertilized in vitro and in vivo were suppressed when the embryos were cultured with PS or HCS as compared with BSA. In the medium supplemented with HCS, growth of in vitro fertilized embryos was retarded at an earlier embryonic stage than was the case with embryos fertilized in vivo. These results suggest that the in vitro fertilized embryo culture model is more sensitive to culture conditions than is the in vivo fertilized embryo culture model. Incorporations of [3H]uridine and [3H]leucine were measured using embryos that developed to the blastocyst stage in a medium supplemented with HCS or BSA. Blastocysts cultured with HCS showed significantly higher incorporations of [3H]uridine and [3H]leucine than those cultured with BSA. While serum supplementation in culture media has adverse effects on embryo cleavage, it augments synthesis of RNA and protein.

Animals↗
PubMed2006

Structure and activity of the denitrifying community in a maize-cropped field fertilized with composted pig manure or ammonium nitrate.

One alternative to mineral fertilization is to use organic fertilizers. Our aim was to compare the impacts of 7-year applications of composted pig manure and ammonium nitrate on the structure and activity of the denitrifying community. Mineralization and organization of N, denitrification rates and N2O/N2 ratio were also investigated. Fourteen months after the last application, the potential denitrifying activity (+319%), N mineralization (+110%) and organization (+112%) were higher under pig compost than under ammonium nitrate fertilization. On the other hand, the N2O/(N2O+N2) ratio was lower (P<0.05, n=5) under organic fertilization. These effects of organic fertilization were in accordance with its higher total carbon content and microbial biomass. Fingerprints and clone library analyses showed that the structure of the denitrifying community was affected by the fertilization regime. Our results reveal that organic or mineral fertilizer applications could affect both structure and activity of the denitrifying community, with a possible influence on in situ N2O fluxes. These effects of the fertilization regime persisted for at least 14 months after the last application.

Amino Acid Sequence↗
PubMed1985

Polyspermy in in vitro fertilization of human oocytes: frequency and possible causes.

In an IVF program a total of 585 oocytes (180 patients) were examined for the presence of pronuclei 16 to 20 hours after the addition of spermatozoa. The overall fertilization rate was 71%, and in 58 (10%) of the fertilized oocytes, three or more pronuclei, indicating a failure of the block to polyspermy, could be observed. The frequency of polyspermy was related to the maturity of the oocyte, determined according to morphologic criteria. Immature oocytes showed a higher percentage of polyspermic fertilization (32%) compared to that of mature oocytes (6%). Preincubation of oocytes (for 0.5-1.5, 2-4, and 5-8 hours) prior to the addition of spermatozoa increased the fertilization rate (to 67%, 70%, and 83%, respectively). The polyspermy rate, however, was not significantly different between the various preincubation intervals (13%, 14%, and 19%, respectively). The polyspermy rate was affected by the number of spermatozoa used for in vitro fertilization. Insemination with 0.5-0.8, 1.0, or 1.5-2.0 X 10(6) spermatozoa/oocyte resulted in a polyspermy rate of 6%, 20%, and 32%, respectively. The appearance of polyspermic fertilization was not related to the age of the patient (which ranged from 20 to 45 years) nor to the method of ovarian stimulation (clomiphene, hMG, or clomiphene/hMG). Because of the high incidence of polyspermy under in vitro conditions it seems to be important to routinely examine the oocytes in the pronuclear stage. Reduction of the number of spermatozoa used for in vitro fertilization and the exact timing of insemination according to the maturity of the oocyte might reduce the occurrence of polyspermic fertilization.

Female↗
PubMed2000

The timing of the "fertile window" in the menstrual cycle: day specific estimates from a prospective study.

OBJECTIVES: To provide specific estimates of the likely occurrence of the six fertile days (the "fertile window") during the menstrual cycle. DESIGN: Prospective cohort study. PARTICIPANTS: 221 healthy women who were planning a pregnancy. MAIN OUTCOME MEASURES: The timing of ovulation in 696 menstrual cycles, estimated using urinary metabolites of oestrogen and progesterone. RESULTS: The fertile window occurred during a broad range of days in the menstrual cycle. On every day between days 6 and 21, women had at minimum a 10% probability of being in their fertile window. Women cannot predict a sporadic late ovulation; 4-6% of women whose cycles had not yet resumed were potentially fertile in the fifth week of their cycle. CONCLUSIONS: In only about 30% of women is the fertile window entirely within the days of the menstrual cycle identified by clinical guidelines-that is, between days 10 and 17. Most women reach their fertile window earlier and others much later. Women should be advised that the timing of their fertile window can be highly unpredictable, even if their cycles are usually regular.

Estrogens↗
PubMed2002

The general fertility rate in women with psychotic disorders.

OBJECTIVE: This study determined the general fertility rate and age-specific fertility rates for women with psychotic disorders. METHOD: This historical matched-cohort study of patient records from a primary care database (the General Practice Research Database) was carried out for women of childbearing age (15-44 years) with psychotic disorders. RESULTS: The women with psychotic disorders (N=7,936) had a lower overall general fertility rate than the normal comparison subjects (N=23,023), although fertility was only significantly lower in the women aged 25 and above. This lower fertility rate was less marked in women with affective psychoses. There was no evidence that treatment with neuroleptics influenced the fertility rate in women with non-affective psychoses. CONCLUSIONS: This study found markedly lower fertility rates in women with psychotic disorders than in matched normal comparison subjects, particularly in women with non-affective disorders. Knowledge of fertility rates in women with psychotic disorders is fundamental for clinicians and researchers, since it has implications for family planning services, prevention of obstetric complications, child-care support, and hypotheses about the etiology of these disorders.

Adolescent↗
PubMed2004

Oocyte production and sperm utilization patterns in semi-fertile strains of Caenorhabditis elegans.

BACKGROUND: Caenorhabditis elegans hermaphrodites are capable of producing hundreds of progeny. However, genetic and environmental factors can keep many animals from attaining their full reproductive potential. In these situations, efficient use of any functional gametes becomes more important for reproductive success. To learn about this aspect of C. elegans reproductive biology, we examined oocyte production and sperm utilization patterns in a unique collection of semi-fertile sperm function mutants. RESULTS: In the mutants examined here, broods can be very small but sperm induced high levels of ovulation. Ovulation rates reach maximum levels between the first and second day of adulthood. Ovulations rates remain high during the reproductive period and gradually decline with age. These results further demonstrate a decoupling of the ability of sperm to fertilize oocytes and induce ovulation. We also observe that in our semi-fertile mutants the peak of successful fertilization events precedes the bulk of oocyte production. Mixing populations of functional and nonfunctional sperm under conditions without sperm competition also shows that functional sperm are utilized efficiently. Although overall brood size can be similar for different mutant strains, slight differences in the pattern of sperm utilization in these strains can lead to significant differences in resource utilization and population growth. CONCLUSIONS: This study represents the first detailed description of oocyte and progeny production patterns over the entire reproductive period for wild-type and fertility impaired strains of C. elegans. The phenotype of our mutants provide an ideal system for studying sperm utilization patterns since they only affect one major process, the ability to fertilize oocytes. In semi-fertile mutants, the nature of the reproductive process and/or specific molecular mechanisms ensures that any functional sperm are utilized quickly. Only a fraction of the sperm produced by our semi-sterile mutants are functional as opposed to every sperm having a low but equal chance of fertilizing an oocyte. In addition to the number of progeny produced, the pattern of progeny production can have an important influence on the dynamics of population growth.

Animals↗
PubMed2005

Fertility- and menopause-related information needs of younger women with a diagnosis of early breast cancer.

PURPOSE: The use of chemotherapy and endocrine therapies in the treatment of premenopausal women carries with it reproductive and gynecologic implications that young women may find distressing and discordant with plans for childbearing. This multicenter study aimed to investigate fertility- and menopause-related information needs among young women with a diagnosis of early-stage breast cancer. PATIENTS AND METHODS: Two hundred twenty-eight women with a diagnosis of early-stage breast cancer who were aged 40 years or younger at diagnosis and who were 6 to 60 months after diagnosis were entered onto the trial. Participants completed a mailed self-report questionnaire that included a purposely designed fertility- and menopause-related information needs survey and standardized measures of distress, anxiety, quality of life, menopausal symptoms, and information-seeking style. RESULTS: Seventy-one percent of participants discussed fertility-related issues with a health professional as part of their breast cancer treatment, and 86% discussed menopause-related issues. Consultation with a fertility or menopause specialist was the most preferred method of obtaining this information. Receiving fertility-related information was rated as being significantly more important than receiving menopause-related information at time of diagnosis (P < .001) and at treatment decision making (P = .058). Receiving menopause-related information was rated as being significantly more important than receiving fertility-related information during adjuvant treatment (P < .05), at completion of adjuvant treatment (P < .001), and during follow-up (P < .001). Common questions, sources of information, and correlates of perceived importance were identified. CONCLUSION: The results of this study suggest that younger women have unmet needs for fertility- and menopause-related information and provide preliminary empirical data to guide the development of better fertility- and menopause-related patient education materials for younger women with a diagnosis of early breast cancer.

Adult↗
PubMed1984

Gonadotropin and prolactin levels in follicular fluid of human ova successfully fertilized in vitro.

Follicular fluid (FF) and oocytes were obtained from 94 follicles of 36 women for fertilization in vitro. Ovulation was induced with human menopausal gonadotropin, and follicular aspiration was performed 36 h after an ovulatory injection of hCG. The concentrations of immunoreactive hCG, FSH, and PRL were correlated with the degree of maturation of the oocyte-corona-cumulus complex mass (OCCC), fertilization, rate of cleavage, and the incidence of pregnancy after embryo transfer. Immature OCCC were derived from follicles that contained significantly lower levels of FSH than those from which intermediate and mature OCCC were derived (5.2 +/- 0.6 vs. 11.1 +/- 1.2 mlU/ml; P less than 0.05). FF from oocytes that were successfully fertilized contained higher levels of both hCG and FSH than FF surrounding oocytes that did not fertilize (136.7 +/- 8.7 vs. 108.5 +/- 10.3 mlU/ml hCG; 10.55 +/- 0.6 vs. 5.3 +/- 0.8 mIU FSH, respectively). There was no correlation between early embryonic growth rate and FF concentrations of FSH, hCG, and PRL. Ova reaching the two-cell stage 40 h after fertilization in vitro were associated with the same FF concentrations of FSH, hCG, and PRL as those that cleaved to the four-cell stage. The PRL concentration in FF was significantly higher in mature fertilized ova and in fertilized ova that were associated with a successful pregnancy. It is suggested that the intrafollicular concentration of FSH is associated with the degree of mucification of the OCCC, but FF levels of both FSH and hCG are associated with successful fertilization. High levels of PRL in FF were associated with successful pregnancy and may imply a role of this hormone in oocyte maturation.

Adult↗
PubMed1992

Polyphosphoinositide metabolism during the fertilization wave in sea urchin eggs.

A transient increase in intracellular free calcium is believed to be the signal responsible for the stimulation of the egg metabolism at fertilization and the resumption of the cell cycle. We have studied how the polyphosphoinositides (PPI) turn over at fertilization in sea urchin eggs, in order to determine the relationship between the metabolism of these lipids and the calcium signal. We compare the patterns of PPI turnover that occur during the first minute following fertilization in eggs in which PPI are labelled to steady state with [3H]inositol or [3H]arachidonate with that in which PPI are labelled for a shorter period with [3H]inositol. When eggs are labelled to apparent isotopic equilibrium with either [3H]inositol or [3H]arachidonate, no early increase in [3H]PtdInsP2 occurs while PtdIns decreases slightly. On the contrary, when not labelled to isotopic equilibrium, all [3H]PPI increase during the first 15 seconds following fertilization. We find that, within seconds, fertilization triggers a 600-fold increase in the turnover of PPI, producing an amount of InsP3 apparently sufficient to trigger calcium release. We suggest that phosphoinositidase C and PtdInsP kinase, responsible respectively for the hydrolysis and synthesis of PtdInsP2, are both stimulated to a comparable degree in the first 30 seconds following fertilization and that net changes in the amount of PtdInsP2 at fertilization are very sensitive to the relative levels of activation of the two enzymes. Activating the eggs with the calcium ionophore A23187 showed that both these enzymes are sensitive to calcium, suggesting that calcium-dependent InsP3 production might play a role in the initiation and/or the propagation of the fertilization calcium wave.(ABSTRACT TRUNCATED AT 250 WORDS)

1-Phosphatidylinositol 4-Kinase↗
PubMed1979

Fertilization in brown algae. II. Evidence for lectin-sensitive complementary receptors involved in gamete recognition in Fucus serratus.

Fertilization in Fucus serratus is directly proportional to the number of sperm added, saturating at approximately 250 sperm per egg with an apparent Km of 120 sperm per egg. The effect of a range of lectins on fertilization has been tested. Preincubation of gametes with Con A and fucose-binding protein (FBP) inhibited fertilization. At low concentrations this was by specifically binding to eggs; at high concentrations pretreatment of either gametes inhibited fertilization probably due to cytotoxicity. Fertilization was not inhibited by simple sugar haptens, but polysaccharides containing fucosyl or mannosyl residues (yeast mannan, fucoidan, ascophyllan) inhibited fertilization by binding to sperm. Pretreatment of eggs with alpha-fucosidase or alpha-mannosidase was effective in inhibiting fertilization. All the results indirectly demonstrate that fertilization in Fucus serratus is based on an association between fucosyl- and mannosyl-containing ligands on the egg surface and specific carbohydrate-binding receptors on the sperm surface.

Carbohydrates↗