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PubMed1995

Micropuncture retrieval of epididymal sperm with in vitro fertilization: importance of in vitro micromanipulation techniques.

OBJECTIVES: To evaluate the importance of in vitro micromanipulation techniques, specifically intracytoplasmic sperm injection (ICSI), for the fertility treatment of men with congenital absence of the vas deferens (CAV) or other unreconstructable male reproductive tract obstruction. METHODS: Results using ICSI during in vitro fertilization (IVF) were compared to previously published results of IVF alone and IVF with other micromanipulation techniques at the same infertility center. Main outcome parameters evaluated were: fertilization rate per oocyte, clinical pregnancy rate, and ongoing pregnancies and deliveries. RESULTS: IVF with ICSI yielded a fertilization rate per oocyte of 140 of 312 (45%) and a clinical pregnancy rate of 14 of 27 (52%) per cycle of sperm and egg retrieval. Ongoing pregnancies or deliveries have occurred for 13 of 27 (48%) cycles with ICSI. These results were better than our previously published results of IVF alone or in conjunction with the micromanipulation techniques of subzonal insertion (SuZI) or partial zona dissection (PZD) that yielded a 119 of 631 (19%; P < 0.0001) fertilization rate, clinical pregnancy rate of 14 of 51 (27%; P < 0.001) and ongoing pregnancy or delivery for 12 of 51 cycles (24%; P < 0.001). CONCLUSIONS: Epididymal sperm retrieval should be performed only when micromanipulation is available in conjunction with IVF to maximize chances of fertilization and subsequent pregnancies. The use of ICSI for epididymal sperm appears to maximize chances of pregnancy for couples with surgically unreconstructable obstructive male infertility.

Cytoplasm↗
PubMed2001

Pentoxifylline improves in vitro fertilization and subsequent development of bovine oocytes.

The purpose of this study was to examine whether pentoxifylline improves in vitro fertilization and developmental rates of bovine oocytes. In the first experiment, we examined the effects on the fertilization rate of various concentrations of pentoxifylline (0-7.5 mM) combined with heparin (10 IU/mL). In the second experiment, we examined fertilization cleavage and blastocyst rates after frozen-thawed spermatozoa, obtained from four different bulls, were incubated with heparin (10 IU/mL) with or without caffeine (5 mM) or pentoxifylline (5 mM). In the first experiment, a significantly higher fertilization rate was obtained in heparin containing 5 mM pentoxifylline compared to that in heparin alone or in heparin containing 7.5 mM pentoxifylline (86% vs 60% vs 64%, respectively). The percentage of monospermy in 5 mM pentoxifylline (81%) was significantly higher than in heparin alone (57%). In the second experiment, the interactions among Bulls A, B, C, and D; between treatments (pentoxifylline-with-heparin, caffeine-with-heparin and heparin alone), and between bulls and treatments were analyzed for the number of oocytes penetrated, monospermic oocytes, cleaved oocytes and blastocysts. Among bulls, there was a significant difference in the number of oocytes penetrated (P < 0.01), monospermic oocytes (P < 0.05), cleaved oocytes (P < 0.001), and blastocysts (P < 0.001). Between treatments, there was a significant difference in the number of oocytes penetrated (P < 0.001), monospermic oocytes (P < 0.01) and cleaved oocytes (P < 0.001). Interaction between bulls and treatments was observed for the number of oocytes penetrated (P < 0.05). Individually, for Bulls A, C and D, the numbers of oocytes penetrated and monospermic oocytes in pentoxifylline-with-heparin were significantly higher than in heparin alone. For Bull D, significantly higher results were obtained for the number of oocytes penetrated, monospermic oocytes, cleaved oocytes and blastocysts in pentoxifylline-with-heparin compared to caffeine-with-heparin and heparin alone (P < 0.05). These results suggest that treating sperm with 5 mM pentoxifylline in combination with heparin is effective for bovine in vitro fertilization and it that this treatment is effective even for bulls that produce low fertilization and blastocysts after sperm treatment with caffeine-with-heparin or heparin alone.

Animals↗
PubMed2000

Effect of freezing rate of ram spermatozoa on subsequent fertility in vivo and in vitro.

Ram spermatozoa are most susceptible to damage during freezing between the temperatures of -10 degrees C and -25 degrees C. The objectives of the present study were to examine how freezing rate through this critical temperature zone affected the fertility of spermatozoa as assessed in vivo and in vitro. Semen from six adult rams was frozen at two different rates ("fast": 5 degrees C/min from +5 to -25 degrees C; "slow": 0.5 degrees C/min from +5 to -25 degrees C). In Experiment 1, semen from the fast and slow treatments was used to fertilize ovine oocytes that had been matured in vitro. Semen from the fast treatment yielded a higher cleavage rate (57% vs. 26%; P<0.001) and more blastocysts per oocyte (28% vs. 13%, P<0. 001) than slow-frozen. No correlation was found between fertilizing ability and viability as assessed by fluorescent probes. Experiment 2 was designed to establish the conception rates following both cervical and intrauterine insemination of frozen-thawed semen from the same bank of semen as used in Experiment 1. Ewes were superovulated with FSH and inseminated by laparoscopy with frozen semen. A significant difference was found in the number of fertilized ova following embryo recovery (81.4% vs. 39.3%; P<0.001). In a further study, 119 mature cull ewes were inseminated following a 12-day synchronization treatment with frozen semen by either intrauterine (laparoscopic) or cervical insemination. Insemination with fast-frozen semen resulted in a significantly higher pregnancy rate (P<0.05) irrespective of method of insemination. The data show that freezing rate affects the proportion of spermatozoa that retain their fertilizing ability post-thawing. However, once fertilization has occurred, development to the blastocyst stage is independent of freezing rate.

Animals↗
PubMed1991

Fertility levels and trends in Arsi and Shoa regions of Central Ethiopia.

Levels and trends of fertility in the Arsi and Shoa regions of Central Ethiopia are examined, using data from the 1986 Population, Health and Nutrition baseline survey of the Ministry of Health of Ethiopia. The population has high fertility. Total fertility of six children per woman in the late 1960s increased to eight children per woman in the early 1980s, then declined to seven children per woman in the mid-1980s. Urban fertility declined by a substantial amount during the 15 years before the survey while rural fertility increased during the same period. The implications of high fertility are considered.

Adolescent↗
PubMed1993

Attenuation of nursing-related ovarian suppression and high fertility in well-nourished, intensively breast-feeding Amele women of lowland Papua New Guinea.

Intense, sustained nursing lengthens inter-birth intervals and is causally linked with low natural fertility. However, in traditional settings, the effects of such nursing on fertility are difficult to disentangle from those of nutrition. Results from a prospective, direct observational study of reproductive function in well-nourished Amele women who nurse intensively and persistently but who also have high fertility are here presented. Endocrine measures show that ovarian activity resumes by median 11.0 months postpartum. Median duration of postpartum amenorrhoea is 11.3 months, time to next conception is 19.0 months, and the inter-birth interval is 28.0 months. Average life time fertility is 6.8. High fertility in Amele women is due both to refractoriness of reproductive function to suckling stimuli, and to maintenance of equivalent age-specific fertility rates across the reproductive life span.

Birth Intervals↗
PubMed1993

Effects of family sex composition on fertility preference and behaviour in rural Bangladesh.

The effects of family sex composition on fertility preferences and behaviour during the period 1977-88 are examined using longitudinal data from Matlab, Bangladesh. The sex composition of living children was found to be systematically related to fertility preferences and behaviour, with a higher number of sons at each family size associated with a higher percentage of women wanting no more children, a higher percentage currently using contraception, and lower subsequent fertility. However, the highest percentage wanting no more children, using contraception and having lowest subsequent fertility was found among women who already had one daughter as well as at least one son. The effects of sex preference on fertility preferences and behaviour were measured using an index developed by Arnold (1985). The results suggest that while sex preference remained largely unchanged during the study period, its effect on contraceptive use declined and its impact on actual fertility remained modest and fairly stable.

Adult↗
PubMed1997

Family size and sex preferences and eventual fertility in Botswana.

Botswana is one of the sub-Saharan countries where actual fertility has declined. This study examines the fertility preferences of both men and women and shows that fertility intentions have a significant influence on future fertility behaviour. Fertility preferences are relatively low and there is no significant difference between those of men and women. Men's preference for sons influences desired family size and eventual fertility. For women as well as men, child survival is an important factor. Women's income is also influential.

Adolescent↗
PubMed2004

The effect of a two-hour, room temperature incubation of human spermatozoa in TEST-yolk buffer on the rate of fertilization in vitro.

PURPOSE: To reassess the use of TEST-yolk buffer (TYB) in an in vitro fertilization (IVF) program by comparing fertilization rates achieved in a glucose-free cleavage medium by the standard IVF preparation of sperm versus a 2-h, room temperature incubation of sperm in TYB. METHODS: Oocytes collected for IVF were randomly split into two groups and inseminated with either TYB-treated sperm or IVF-prepared sperm. SETTING: Stanford Reproductive Endocrinology and Infertility Center. PATIENTS: Fifty couples undergoing IVF with at least 10 mature oocytes. MAIN OUTCOME MEASURES: Fertilization rates in vitro. RESULTS: Fertilization rates were significantly higher (p = 0.015) with TYB treatment. The average 2PN fertilization rate was 49.6% (188/379) for the IVF group and 57.4% (221/385) in the IVF with TYB group. CONCLUSIONS: A 2-h, room temperature incubation of sperm in TYB produces significantly higher 2PN fertilization rates as compared to standard IVF preparation of sperm in a current generation cleavage medium.

Culture Media↗
PubMed2002

Function of the cumulus oophorus before and during mammalian fertilization.

CONTENTS: Fertilization encompasses a series of different steps which have to be performed in a well-orchestrated way to create a new individual. They include sperm capacitation, sperm binding and penetration of the zona pellucida, traversing the perivitelline space, binding and fusion with the oolemma, activation of the oocyte and decondensation of the sperm head to form the male pronucleus. In most mammalian species, cumulus cells surround the oocyte at the time of fertilization. Removal of the cumulus oophorus at this point of time often leads to a drop in fertilization rates. It is not yet known how cumulus cells interact with the oocyte or with spermatozoa to promote fertilization. There are different possibilities: 1 cumulus cells cause mechanical entrapment of spermatozoa and guide hyperactivated spermatozoa towards the oocyte, while preventing abnormal spermatozoa to enter the cumulus matrix; 2 cumulus cells create a micro-environment for the spermatozoa which favours their capacitation and penetration into the oocyte; 3 cumulus cells prevent changes in the oocyte which are unfavourable for normal fertilization; these changes can be located in the zona pellucida or in the cytoplasm. In this review, studies in several species are listed to prove the importance of these three cumulus cell functions and the current lines of research are highlighted. Moreover, different ways to improve in vitro fertilization of bovine cumulus-denuded oocytes are discussed.

Animals↗
PubMedDate not supplied

Fertility attitudes and behavior of Saudi Arabian students enrolled in U.S. universities.

Although fertility declines have taken place in several Arab countries, the Arab nations are growing rapidly. In Saudi Arabia, the total fertility rate (TFR) is 7.1, and the growth rate is 3.5 per cent per year, among the highest in the world. This research examines the structural determinants (indirect indicators) of fertility attitudes and behavior among Saudi Arabian students studying in American universities. Specifically, this study examined the relationship between fertility attitudes and behavior, and background characteristics which included age, religiosity, education, income, length of stay in the U.S., and wife's age and wife's education. Results indicate a highly significant effect of religiosity as a major positive determinant of fertility attitudes. However, the major determinant of fertility behavior, the number of children respondents had, was wife's education which was negatively related with family size.

Adult↗
PubMedDate not supplied

Reproductive change in Zimbabwe and Kenya: the role of the proximate determinants in recent fertility trends.

This study examines trends in proximate determinants of fertility in Zimbabwe and Kenya. Findings from the four Demographic and Health Surveys conducted in these countries show that the dramatic fall in fertility in these countries is consistent with the underlying trends in the most important proximate determinants of fertility. In Zimbabwe, contraceptive use far exceeds other proximate determinants in influencing fertility levels and trends. The results show that the fertility inhibiting effects of contraception are more important than the effects of postpartum infecundability, marriage patterns, or sterility. The results also show that contraceptive use has its greatest suppressing effects in the middle and younger age groups. However, in Kenya, the dominant fertility inhibiting effect is postpartum infecundability, with contraception coming in second.

Adolescent↗
PubMed1998

Do men undergoing sterilizing cancer treatments have a fertile future?

This study was designed to assess the effect of cancer treatments on the natural and assisted reproductive potential of men. A cohort of men with cancer, in whom radiotherapy and/or chemotherapy was planned, were invited to participate. Twenty-two pre- and post-treatment semen samples were analysed. The reproductive potential of participants was assessed with respect to the current range of fertility treatment options available. Abnormal sperm concentrations were found in 27% of patients pre-treatment compared to 68% post-treatment following a mean latency of 20 months from treatment. Fifty-nine percent of patients experienced a clinically significant decrease in sperm, concentration following radiotherapy and/or chemotherapy; 23% developed azoospermia following treatment. Eighty-two percent of patients with testicular malignancy had oligo- or azoospermia post-treatment. Only one patient had a clinically significant reduction in the percentage of motile spermatozoa post-treatment. Cryopreservation of semen prior to treatment improved the fertility prospects of 55% of patients. Intracytoplasmic sperm injection (ICSI) enhanced the fertility prospects of a further 14%. In the absence of, or after depletion of, cryopreserved semen, ICSI could enhance the fertility prospects of 45% of patients. Fertilization has been achieved by ICSI using spermatozoa retrieved by testicular biopsy from an azoospermic testicular cancer survivor 8 years after chemotherapy. It was concluded that chemotherapy and/or radiotherapy may depress semen concentration to the extent of rendering a man infertile. The severity of the reduction in sperm concentration following treatment is unpredictable but likely to be most severe in those with testicular malignancy and those treated with radiotherapy or alkylating chemotherapy agents. Not all men are keen to undergo an appraisal of their post-treatment fertility potential, for reasons which are unclear. Improving awareness and education of patients concerning the effects of both cancer and cancer treatments on reproductive potential is essential. With the advent of ICSI, it is possible to offer a very reasonable chance of conception in all men with cancer who present for cryopreservation of semen prior to treatment in whom spermatozoa (even in very low concentrations) are present in the ejaculate.

Adult↗
PubMed1995

Sperm morphology assessment: historical review in relation to fertility.

Careful analysis of sperm morphology has always been an important part of a routine semen examination. However, the usefulness of sperm morphology assessment as a predictor of a man's fertilizing potential has often been challenged due to different classification systems, various slide preparation techniques and inconsistency of analyses within and between laboratories. Automated sperm morphology analysis instruments may overcome the subjective nature of visual assessments of sperm morphology, but the technical problems are numerous and the validity of these instruments has still to be proven. Having reviewed the literature, it seems clear that there is general agreement concerning the clinical relevance and predictive value of this single semen parameter in vivo and in vitro. Nevertheless, even in cases of severe teratozoospermia, fertilization may be possible. Studies on the acrosome reaction are very promising for patients with severe sperm morphology abnormalities that do not have major effects on the fertilizing potential. Most promising is the development of intracytoplasmic sperm injection (ICSI) as the treatment of first choice in cases of severe teratozoospermia with failed fertilization in vitro. Normal fertilization and pregnancy rates can be obtained with ICSI in the presence of extreme teratozoospermia, suggesting that sperm morphology may be important in spermatozoa-zona binding, penetration and spermatozoon-oocyte fusion but fails to be of any predictive value once the spermatozoon reaches the cytoplasm of the oocyte. To conclude, accurate and strict sperm morphology assessment is very useful in evaluating a patient's fertilizing potential, with the main advantage that the methods used to examine this parameter are easy to learn on equipment found in most laboratories.

Classification↗
PubMed1986

Association of the in-vitro fertilizing capacity of human spermatozoa with sperm morphology as assessed by three classification systems.

Stained sperm morphology slides from an in-vitro fertilization programme were evaluated by the modified Williams system, the World Health Organization (WHO) system and morphometric size measurements (image analysis) to determine which system(s) were better predictors of fertility. Amorphous sperm head shape was the best predictor of fertility in both the modified Williams system and the WHO system, predicting the proper fertility status in 65% of the cases. Using only normal sperm in the statistical model, normal sperm became a correct predictor in 66% of the cases in the modified Williams system. Morphometric measurements were not useful in predicting the fertility status of these samples. These studies indicate that morphology can not be used as a sole predictor of fertilizing capacity of human spermatozoa.

Fertility↗
PubMed1990

Relationships between human sperm acrosin, acrosomes, morphology and fertilization in vitro.

Acrosin was measured in the semen used for sperm preparation for in-vitro fertilization (IVF) in 118 patients. Acrosin levels correlated with the proportion of spermatozoa with normal intact acrosomes determined with Pisum sativum agglutinin labelled with fluorescein. However, acrosin levels and the proportion of spermatozoa with normal intact acrosomes in semen were not significantly related to the fertilization rate in vitro. Only the percentage normal morphology and sperm concentration in the insemination medium were independently significantly related to the fertilization rate by logistic regression analysis. In patients with fewer than 30% of spermatozoa with normal morphology, although acrosin levels were not correlated with the fertilization rate, the proportion of spermatozoa with normal intact acrosomes in the insemination medium was the only significant factor in the logistic regression analysis. In conclusion, acrosin levels have no prognostic value for fertilization in vitro but the proportion of spermatozoa with normal intact acrosomes may be a useful clinical marker of fertilizing ability in men with poor sperm morphology.

Acrosin↗
PubMed1986

Bicarbonate is essential for fertilization of mouse eggs: mouse sperm require it to undergo the acrosome reaction.

Fertilization of mouse eggs by capacitated mouse sperm occurs readily in vitro in a defined culture medium designated medium CM, derived from Krebs-Ringer bicarbonate medium by supplementation with glucose, lactate, pyruvate, and albumin. Medium CM contains 25 mM HCO-3 equilibrated with CO2 to pH 7.4. Replacement of the CO2/HCO-3 buffer with 25 mM N-hydroxyethylpiperazine-N-ethanesulfonate (HEPES) while otherwise maintaining pH, ionic strength, and composition identical to that of medium CM, yielded medium HM in which the percentage of in vitro fertilization observed was consistently zero. Addition of 10 mM HCO-3 to medium HM yielded medium HMB, in which the percentage of eggs fertilized was 70%, equal to that observed in medium CM. This percentage applies to cumulus-free, zona-intact eggs. With zona-free eggs, the percentage fertilization increased to 90% in media CM and HMB, but remained zero in medium HM. This result shows that HEPES does not inhibit fertilization while omission of CO2/HCO-3 blocks it completely. Capacitation of mouse sperm, as determined by chlortetracycline fluorescence assay, proceeded at the same rate in media CM and HMB, but was retarded in medium HM. Sufficient sperm became capacitated, however, that this could not be the block of fertilization. The acrosome reaction in sperm bound to isolated zonae pellucidae, as also determined by chlortetracycline fluorescence assay, occurred with the same time course in media CM and HMB, but did not occur in medium HM.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrosome↗
PubMed1998

Spontaneous and fertilization-induced Ca2+ oscillations in mouse immature germinal vesicle-stage oocytes.

Mouse germinal vesicle (GV)-stage oocytes not only show Ca2+ oscillations in response to fertilization but also exhibit spontaneous Ca2+ oscillations during meiotic maturation in vitro. Spontaneous Ca2+ oscillations were entirely suppressed by microinjection of heparin (25 microM final intracellular concentration), an antagonist of inositol trisphosphate (IP3) receptor, whereas fertilization-induced Ca2+ oscillations were only partially inhibited by heparin even at a high dosage of 600 microM. Inhibition of endogenous IP3 generation by antagonizing phospholipase C using U73122 (20 microM final concentration) also failed to suppress the generation of fertilization-induced Ca2+ transients, suggesting that the two types of Ca2+ oscillations do not have the same dependence on IP3-induced Ca2+ release. In addition, spontaneous Ca2+ oscillations require the presence of intact GV whereas fertilization-induced Ca2+ oscillations are independent of the GV but require cytoplasm, since enucleation eliminated only spontaneous Ca2+ oscillations but not fertilization-induced Ca2+ oscillations. These results suggest that IP3-induced Ca2+ release is the primary mechanism responsible for spontaneous Ca2+ oscillations. Sperm-induced Ca2+ oscillations, however, may employ more complex mechanisms during fertilization.

Animals↗
PubMed2000

Ability of integrins to mediate fertilization, intracellular calcium release, and parthenogenetic development in bovine oocytes.

The ability of arginine-glycine-aspartic acid (RGD; a sequence recognized by integrins) or non-RGD-containing peptides to block fertilization, induce intracellular Ca(2+) oscillations, and initiate parthenogenetic development in bovine oocytes was investigated. Addition of a soluble RGD peptide during fertilization at concentrations ranging from 10 to 1000 microg/ml significantly decreased (P<0.05) fertilization as compared to the in vitro-fertilized controls. The addition of non-RGD peptide had no effect on fertilization. Two intracellular Ca(2+) transients 21.5+/- 1.9 min apart were observed in 56 of 60 oocytes incubated in RGD peptide concentrations ranging from 20 to 1000 microg/ml. No intracellular Ca(2+) transients were observed in medium alone, non-RGD treatment groups or in the RGD peptide at 10 microg/ml. The percentage of oocytes activated with ionomycin and 6-dimethylaminopurine (63% cleavage and 34% blastocyst development) was significantly higher (P<0.05) than those activated with the RGD peptide and 6-dimethylaminopurine (35% cleavage and 19% blastocyst development). These groups were significantly higher (P<0.05) than either peptide alone, 6-dimethylaminopurine alone, or the non-RGD peptide and 6-dimethylaminopurine treatment groups. These data provide evidence that ligation of an integrin on bovine oocytes with a soluble RGD peptide is capable of blocking fertilization, inducing intracellular Ca(2+) transients, and initiating parthenogenetic development.

Adenine↗