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PubMed1997

Influence of insemination-ovulation interval and sperm cell dose on fertilization in sows.

This experiment was conducted to determine the effects of sperm dose at insemination on fertilization rates and accessory sperm cells attached to day 5 embryos. Multiparous sows (n = 115) were artificially inseminated once with 1 x 10(9), 3 x 10(9) or 6 x 10(9) sperm cells between 3 h and 48 h before ovulation. Transrectal ultrasonography was performed at intervals of 4 h to determine the time of ovulation and sows were killed at 120 +/- 5 h after ovulation to assess the results of fertilization. The insemination-ovulation interval had a major influence on the fertilization rate and accessory sperm count. A nonsignificant but consistent increase in fertilization rate and in number of accessory sperm cells due to the sperm dose was observed. During the insemination-ovulation interval of 12-24 h, the median fertilization rates were 95%, 100% and 100%, and the median accessory sperm counts were 11, 17 and 31 for the 1 x 10(9), 3 x 10(9) and 6 x 10(9) doses, respectively. During the insemination-ovulation interval of 24-36 h, the median fertilization rates were 88%, 95% and 97%, and the median accessory sperm counts were 6, 8 and 11 for the 1 x 10(9), 3 x 10(9) and 6 x 10(9) doses, respectively. No direct relationship was detected between embryo quality and the accessory sperm count but there was a relationship between insemination-ovulation interval and accessory sperm count. The fertilization rate was positively correlated with the breeding value for litter size of the sows. In conclusion, the effects of sperm dose on fertilization rate and on accessory sperm count in sows were small and nonsignificant, indicating only small effects of sperm dose on the functioning of the sperm reservoir in the sow.

Animals↗

PubMed1984

[The effects of calmodulin and it's antagonist, W-7, on the acrosome reaction and fertilization of human spermatozoa].

The acrosome reaction of mammalian spermatozoa has been shown to be dependent upon an influx of Ca2+ following capacitation. Recently it was shown that calmodulin which activates various enzymatic activities in a calcium-dependent manner is contained in the acrosomal portion of sperm obtained from diverse species including human. Therefore calmodulin appears to be the primary target for Ca2+-dependent regulatory process involved in the acrosome reaction. This report examines the effects of calmodulin and it's antagonist, W-7, on the acrosome reaction in human spermatozoa and the fertilization with zona free hamster eggs. The results are as follows: 1) In the experiment on fertilization in mBWW medium with 30nM of calmodulin, there was no significant difference between the calmodulin and the control. (2) In fertilization in mBWW medium with 2.5 to 25 microM of W-7, there were no significant changes in the fertilization rate, but there was a significant decrease in the fertilization rate when the concentration of W-7 was elevated up to 50 microM. (3) When fertilization in mBWW was performed using spermatozoa pretreated with W-7, the fertilization rates were more markedly and promptly elevated with insemination times than the control. (4) When the eggs and spermatozoa were pretreated with W-7 before insemination and then placed in mBWW medium, the fertilization rate was markedly decreased. (5) Triple stain method and transmission electron microscopy showed that a large proportion of spermatozoa had undergone the acrosome reaction in mBWW medium containing W-7 with normal manner. From the results given above, it appears that calmodulin plays an important role in the acrosome reaction and fertilization in human spermatozoa.

Acrosome↗

PubMed1993

Intracytoplasmic single sperm injection of 1-day-old unfertilized human oocytes.

Although the average fertilization rate in most in-vitro fertilization (IVF) centres is approximately 60-70%, there are cases of complete or virtually complete fertilization failures. The aim of our work was to study the fertilization and the subsequent cleavage characteristics of 1-day-old human oocytes treated by intracytoplasmic single sperm injection (ICSI) after failing to fertilize during the standard IVF procedure. A total of 115 metaphase II 1-day-old unfertilized oocytes were collected from 23 patients. No additional treatment was applied to the oocytes or to the semen sample. A single spermatozoon from the patient's husband was injected into the cytoplasm of each of these oocytes 21-33 h after ovum retrieval. Injected oocytes were observed at 16-18 h and again 42-44 h after the ICSI procedure. Of the injected oocytes, 92% (n = 106) were intact after ICSI, 38% (n = 44) had two distinct pronuclei and there was no difference in the fertilization rate of oocytes when andrological and non-andrological patients were compared. Similarly, there was no difference in the fertilization rate after ICSI where patients with acceptable or good (> 15%) fertilization after standard IVF were compared to patients who had poor (< or = 15%) fertilization after IVF. There was no significant difference in the sperm concentration or in the progressive forward motility (a + b motility) in these groups except where a + b motility of andrological and non-andrological patients was compared. The majority (84%) of the normally fertilized oocytes cleaved and most (77%) of these embryos showed < 20% fragmentation 2 days after the ICSI procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Cellular Senescence↗

PubMedDate not supplied

Advanced methods for evaluation of sperm quality.

Routine semen analysis includes measurements of sperm concentration, motility, and morphology. In our study, three additional tests were evaluated in relation to fertilization rate in an in vitro fertilization program: the freezing and hypo-osmotic swelling tests that evaluate the functional integrity and stability of the sperm membrane under extreme osmotic conditions, and migration sedimentation test that isolates high-quality motile sperm cells. The study was performed on semen delivered by men of couples treated at the In Vitro Fertilization Unit, and men who served as semen donors (fresh or cryopreserved semen). No correlation was found between the sperm fertilization rate, and the decrease in motility percent following the freezing-thawing process. Thus, the freezing test cannot be used to predict semen fertilization capacity. The hypo-osmotic swelling test was applied on semen given by a similar population of men. While the hypo-osmotic swelling test values carried out with fresh semen was found to have good correlation with fertilization, no correlation was found when frozen thawed semen was used. Post-migration sedimentation test sperm characteristics, and especially the recovery rate of the motile sperm, were significantly better in in vitro fertilization cycles with fertilizations. Both the hypo-osmotic swelling test and migration sedimentation test can assist in evaluating semen quality, judged by the fertilization rate in an in vitro fertilization program.

Female↗

PubMed2001

Annual summary of vital statistics: 2000.

The birth rate in 2000 (preliminary data) was 14.8 births per 1000 population, an increase of 2% from 1999 (14.5). The fertility rate, births per 1000 women aged 15 to 44 years, increased 3% to 67.6 in 2000, compared with 65.9 in 1999. The 2000 increases in births and the fertility rate were the third consecutive yearly increases, the largest in many years, halting the steady decline in the number of births and fertility rates in the 1990s. Fertility rates for total white, non-Hispanic white, black, and Native American women each increased about 2% in 2000. The fertility rate for black women, which declined 19% from 1990 to 1996, has changed little since 1996. The rate for Hispanic women rose 4% in 2000 to reach the highest level since 1993. Birth rates for women 30 years or older continued to increase. The proportion of births to unmarried women remained about the same at one third, but the number of births rose 3%. The birth rate for teen mothers declined again for the ninth consecutive year. The use of timely prenatal care (83.2%) remained unchanged in 2000, and was essentially unchanged for non-Hispanic white (88.5%), black (74.2%), and Hispanic (74.4%) mothers. The number and rate of multiple births continued their dramatic rise, but all of the increase was confined to twins; for the first time in more than a decade, the number of triplet and higher-order multiple births declined (4%) between 1998 and 1999 (multiple birth information is not available in preliminary 2000 data). The overall increases in multiple births account, in part, for the lack of improvement in the percentage of low birth weight (LBW) births. LBW remained at 7.6% in 2000. The infant mortality rate (IMR) dropped to 6.9 per 1000 live births (preliminary data) in 2000 (the rate was 7.1 in 1999). The ratio of the IMR among black infants to that for white infants was 2.5 in 2000, the same as in 1999. Racial differences in infant mortality remain a major public health concern. The role of low birth weight in infant mortality remains a major issue. Among all of the states, Utah and Maine had the lowest IMRs. State-by-state differences in IMR reflect racial composition, the percentage LBW, and birth weight-specific neonatal mortality rates for each state. The United States continues to rank poorly in international comparisons of infant mortality. Expectation of life at birth reached a record high of 76.9 years for all gender and race groups combined. Death rates in the United States continue to decline. The age-adjusted death rate for suicide declined 4% between 1999 and 2000; homicide declined 7%. Death rates for children 19 years of age or less declined for 3 of the 5 leading causes in 2000; cancer and suicide levels did not change for children as a group. A large proportion of childhood deaths, however, continue to occur as a result of preventable injuries.

Birth Rate↗

PubMed1994

Evaluation of different sperm function tests as screening methods for male fertilization potential--the value of the sperm migration test.

OBJECTIVE: To assess the value of different sperm function screening tests in predicting fertilization. DESIGN: Prospective study. SETTING: Academic tertiary referral center for fertility treatment. PATIENTS: Ninety-five couples attending for initial screening and IVF-ET. Only cycles where three or more grade I oocytes were collected were included, and patients with endometriosis were excluded. INTERVENTIONS: Each patient had a standard semen analysis, cervical mucus (CM) penetration test, hypo-osmotic swelling test, and sperm migration test performed between 4 and 8 weeks before IVF-ET. MAIN OUTCOME MEASURES: The correlation between sperm function test results and the percentage of fertilized oocytes and the power of the tests to predict fertilization. RESULTS: The sperm migration test correlated highly with fertilization rate (r = 0.62) and was most useful in identifying the group of patients likely to achieve fertilization (Odds ratio [OR] 0.07, confidence interval [CI] 0.02 to 0.2). The CM penetration test showed a moderate correlation with fertilization rate (r = 0.45) and some predictive power (OR 0.37, CI 0.13 to 1.00). Sperm concentration, but not motility or normal morphology, showed slight correlation with fertilization rate (r = 0.28) but the combination of normal semen parameters did not distinguish patients likely to achieve fertilization (OR 1.51, CI 0.62 to 3.65). The hypo-osmotic swelling test did not correlate with fertilization rate (r = 0.21). CONCLUSIONS: This study evaluated the predictive power of several simple tests available for use in most laboratories as screening tests of sperm fertilization potential. Apart from sperm concentration, normal traditional semen characteristics were of little clinical benefit. The hypo-osmotic swelling test had no predictive power. The CM penetration test correlated with fertilization rate but might be difficult to perform routinely as a continuous supply of suitable CM would be required. The sperm migration test proved to be the best discriminator of sperm fertilization potential and should be considered as a first level screening test in the assessment of male fertility.

Cervix Mucus↗

PubMed1995

Annual summary of vital statistics-1994.

Recent trends in the vital statistics of the United States continued in 1994, including decreases in the number of births, the birth rate, the age-adjusted death rate, and the infant mortality rate. Life expectancy increased slightly to 75.7 years. Only marriages reversed the recent trend with a slight increase in 1994. An estimated 3,979,000 infants were born during 1994, a decline of < 1% from 1993. The birth rate was 15.3 live births per 1000 population, a 1% decline. These decreasing rates reflect a decline in the fertility rate to 67.1 live births per 1000 women aged 15 to 44 years. Final figures for 1993 indicate that fertility rates declined for all racial groups, by 1% for white women (to 65.4) and 3% for black women (to 80.5). The fertility rate for Hispanic women (106.9) was 84% higher than that for non-Hispanic white women and 31% higher than for non-Hispanic black women. Between 1991 and 1993, birth rates for teenage mothers remained virtually unchanged, and abortion rates have steadily declined, suggesting that teenage pregnancy rates are levelling off. The number and proportion of births to women over age 30, however, continued to rise. The rate of births to all unmarried women (45.3 per 1000 in 1993) has been stable for 3 years. Prenatal care utilization improved in 1993; 79% of women initiated care in the first trimester and < 5% had delayed care or no care. Improvements occurred among nearly all racial and ethnic groups. Reported smoking during pregnancy declined to 15.8% in 1993 from 16.9% in 1992. The proportion of babies delivered by cesarean section was 21.8% in 1993, a 2% decrease from 1992. Between 1992 and 1993, the rate of low birth weight (LBW) rose slightly to 7.2%, while very low birth weight (VLBW) remained stable at 1.3%. Most of the increase in LBW occurred among white infants and reflected, primarily, an increase in the proportion of multiple births. The black/white ratio in LBW continued to increase to more than two-fold with the largest difference recorded among term and postterm infants. Age-adjusted death rates in 1994 were lower for heart disease, malignant neoplasm, pulmonary diseases, other accidents, and homicides. The age-adjusted death rate for human immunodeficiency virus disease continued to rise to 15.1 in 1994. The infant mortality rate declined 4% in 1994, to 7.9 per 1000, the lowest rate ever recorded in the United States. The decline was primarily in neonatal mortality.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

PubMed1997

Detection of deoxyribonucleic acid fragmentation in human sperm: correlation with fertilization in vitro.

The objective of this study was to determine the incidence of DNA fragmentation in human sperm, and to correlate any detected DNA damage with semen analysis parameters and fertilization rates in in vitro fertilization (IVF). A total of 298 semen samples were collected from men in the infertility program at The Toronto Hospital. For each sample, the percentage of sperm with DNA fragmentation was determined using the method of terminal deoxynucleotidyl transferase-mediated dUTP-biotin end-labeling (TUNEL) and fluorescence-activated cell sorting. The percentage of sperm with fragmented DNA was less than 4% in the majority of samples but ranged from 5% to 40% in approximately 27% of the samples. A negative correlation was found between the percentage of DNA fragmentation and the motility, morphology, and concentration of the ejaculated sperm. In 143 IVF samples, a significant negative association was also found between the percentage of sperm with DNA fragmentation and fertilization rate (p = 0.008) and embryo cleavage rate (p = 0.01). In addition, 35 men who smoked demonstrated an increased percentage of sperm with fragmented DNA (4.7 +/- 1.2%) as compared to 78 nonsmokers (1.1 +/- 0.2%; p = 0.01). These results demonstrate a negative association between semen analysis parameters and sperm with fragmented DNA. Since extremely poor semen samples are the indication for intracytoplasmic sperm injection, there is a high likelihood that sperm with fragmented DNA may be selected by chance and used for oocyte injection, resulting in poor fertilization and/or cleavage rates.

Adult↗

PubMed1995

Factors of importance for the establishment of a successful program of intracytoplasmic sperm injection treatment for male infertility.

OBJECTIVE: To establish an intracytoplasmic sperm injection treatment program for couples with male infertility and to determine those factors important for success. DESIGN: A retrospective analysis of 171 consecutive cycles of intracytoplasmic sperm injection concerning 145 infertile couples. SETTING: Infertility clinic in a private hospital associated with a university hospital. PATIENTS: Couples with infertility in the male partner whose sperm parameters were unacceptable for conventional IVF or in whom fertilization by conventional IVF failed repeatedly. INTERVENTIONS: One hundred seventy-one transvaginal oocyte retrievals were completed after superovulation with GnRH agonist and gonadotropins. MAIN OUTCOME MEASURES: The parameters evaluated included fertilization, cleavage, implantation, pregnancy, and spontaneous abortion in relation to patient indications and improved procedures. RESULTS: After intracytoplasmic sperm injection, normal fertilization occurred in 45% of the oocytes (n = 1,499). Of 171 treatment cycles, 93% of the couples had fertilization and 86% had ET. Thirty-six pregnancies were achieved. During the period studied, the mean fertilization rate increased from 21.3% during the first 17 weeks to 67.8% during the last 13 weeks, and the pregnancy rate (PR) per started cycle increased from 12.8% to 31.3%. CONCLUSIONS: Technical factors critical for achieving high rates of fertilization and pregnancy were the use of standardized intracytoplasmic sperm injection pipettes, the immobilization of sperm before injection, and the aspiration of a minimal amount of ooplasm before reinjection with the sperm. Intracytoplasmic sperm injection appears to be superior to other micromanipulation methods for alleviating male infertility.

Adult↗

PubMed2002

Fertilization efficiency of in vitro matured oocytes transferred to oviducts of inseminated goats: a model to assess in vivo fertilization performance of goat spermatozoa.

An alternative to conventional in vivo validation of sperm assays might be to assess the fertilization rate of multiple oocytes transferred to the oviducts of inseminated females. Increasing the number of oocytes increases the egg-sperm ratio in the oviduct under an unaltered endocrine milieu, setting the basis for picking up statistical differences between treatments in small populations. The study evaluated the model by transferring oocytes to females inseminated under conditions that are known to modify the fertilization rate in the field. The study then evaluated the use of cattle oocytes to replace goat oocytes for assessing sperm function under this model. In Experiment 1, 12 females were inseminated at estrus with either 100 or 300 million spermatozoa 20 h before transferring homologous oocytes into the oviduct ipsilateral to the ovulation point. In Experiment 2, 10 females were inseminated either once or twice; 10-20 h later, homologous oocytes were transferred into the oviduct ipsilateral to the ovulation point. In Experiment 3, 13 bilateral-ovulated females were inseminated and 20 h later goat and cattle oocytes were transferred to contralateral oviducts. Then, 16-20 h later, oocytes were flushed from the oviduct, cleaned of spermatozoa and stained to assess the fertilization rate. The fertilization rate was improved by increasing sperm numbers at insemination (P < 0.04) and by increasing the number of inseminations (P < 0.02). The results in Experiment 3 showed that fertilization rates were similar for goat and cattle oocyte (P > 0.05) and that fertilization values were highly correlated (r = 0.811, P < 0.001). Results suggest that the model can be used for in vivo validation of in vitro sperm assays by facilitating the expression of statistical differences in small number of animals. In addition, cattle oocytes can be used to replace goat oocytes to study in vivo sperm function in goats.

Animals↗

PubMed1997

In vitro fertilization in mice: Strain differences in response to superovulation protocols and effect of cumulus cell removal.

Strain differences have proven to be crucial components in mouse in vitro fertilization (IVF) and superovulatory protocols. To maximize the yield of IVF-derived mouse eggs, a series of experiments was conducted using different injection timing intervals for administration of pregnant mare serum gonadotropin (PMSG) and hCG to induce follicular development and ovulation. Strains were chosen that were representative of those commonly used in genetic engineering experimentation. These strains included ICR outbred, C57BL/6 inbred, and B6SJLF1 hybrid (C57BL/6J x SJL/J F1) mice. Females were superovulated using 4 PMSG/hCG/IVF timing regimens (group), with sperm obtained from males of the same strain. Group designations were based on the following PMSG/hCG and hCG/oocyte collection intervals, respectively: Group 1, 55 and 21.5 h; Group 2, 60 and 14.5 h; Group 3, 55 and 14.5 h; Group 4, 48 and 14.5 h. After overnight culture of ova, fertilization rates (development to the 2-cell stage) were assessed. A logistic regression was performed using indicator variables for both strain and group. There was a significant strain influence on ova fertilization rate, based on the coefficients of mouse strain (ICR, beta = -1.1067, P = 8E-17 and C57BL/6, beta = -0.5172, P = 8E-06). Additionally, group affected the proportion of fertilized ova obtained (coefficient of Group 1, beta = -1.3152, P = 0.00 and Group 3, beta = 0.9531, P = 3E-12). From the coefficients for the interaction terms, the effect of groups varies across mouse strain. Therefore, the treatment that produces the highest fertilization rate is related to and contingent upon the strain of mouse. In the second study, the Group 3 protocol was used to evaluate fertilization differences between cumulus-intact and cumulus-free oocytes. Again, there was a significant strain influence on ova fertilization rate based on the coefficients of mouse strain (ICR, beta = -2.6639, P = 0.00; C57BL/6, beta = -2.5114, P = 0.00). However, there was no difference between Cumulus and No Cumulus groups (cumulus coefficient, beta = 0.1640, P = 0.59872), indicating that there was no affect of cumulus presence on fertilization rate. In summary, responses to standardized mouse IVF protocols vary significantly. The efficiency of IVF procedures can be optimized between and within specific mouse strains by the timing of superovulatory regimens. However, absence of cumulus cells during the IVF procedure does not adversely affect fertilization rate.

Journal Article↗

PubMed2004

Cryopreserved sibling oocytes and intracytoplasmic sperm injection rescue unexpectedly poor fertilization in conventional in vitro fertilization.

PURPOSE: To report a successful pregnancy from cryopreserved sibling oocytes and intracytoplasmic sperm injection (ICSI) for an infertile couple with an unexpectedly low fertilization rate in the fresh in vitro fertilization (IVF) cycle. METHODS: The woman had bilateral tubal obstruction and polycystic ovarian syndrome. The man had normal semen parameters. The couple underwent a cycle of controlled ovarian hyperstimulation in that 20 oocytes were retrieved. Twelve oocytes were conventionally inseminated and eight were cryopreserved using a slow freezing method. However, only one oocyte was fertilized, and no pregnancy was achieved. In the next cycle, the frozen oocytes were thawed and ICSI was performed. RESULTS: After thawing, seven oocytes (88%) survived and one was damaged. Six were at the metaphase II stage and were injected. Five (83%) achieved normal fertilization, and all of them cleaved (100%). After replacement of the embryos, a singleton pregnancy developed. A healthy female baby was delivered at term. Karyotyping revealed 46, XX. CONCLUSIONS: In addition to well-known indications, cryopreservation of excess sibling oocytes for patients receiving IVF has a possible advantage of preventing unexpectedly low fertilization rate or fertilization failures.

Adult↗

PubMed1996

Fertilization after intracytoplasmic sperm injection with cryopreserved testicular spermatozoa.

OBJECTIVE: To assess the possibility of cryopreserving testicular tissue extracted sperm for intracytoplasmic sperm injection (ICSI). DESIGN: A report of two cases. Our study was approved by the Ethical Committee at the Instituto Valenciano de Infertilidad. SETTING: In vitro fertilization program at the Instituto Valenciano de Infertilidad. PATIENTS: Two azoospermic patients with severe spermatogenic failure but with focal spermatogenesis on testicular biopsies. In both cases, a first ICSI attempt with fresh testicular biopsy extracted sperm was unsuccessful. INTERVENTIONS: Cryopreservation of testicular spermatozoa in 100-micro L "pills." Intracytoplasmic sperm injection with thawed testicular spermatozoa. MAIN OUTCOME MEASUREMENTS: Fertilization rate, cleavage rate, embryo quality, clinical pregnancy. RESULTS: Fertilization rates were 36 percent and 100 percent after ICSI with fresh testicular spermatozoa, and 63 percent and 57 percent after ICSI with cryopreserved testicular sperm. In both cases, cleavage rates and embryo quality were similar when using fresh and cryopreserved testicular spermatozoa. No clinical pregnancies were achieved. CONCLUSION: High fertilization rates can be obtained after ICSI with frozen-thawed testicular tissue extracted spermatozoa. Cryopreservation of testicular sperm may avoid repetition of testicular biopsies in azoospermic patients in whom the only source of spermatozoa is the testicle.

Adult↗

PubMed1990

The cryopreservation of donor semen by a simplified method: use in an IVF and GIFT programme.

The cryopreservation of semen used in assisted reproduction procedures was carried out exclusively by a simplified method in which a mixture of semen and cryoprotectant was contained in 1-ml tuberculin syringes and plunged directly into liquid nitrogen. Donor semen samples halved and frozen in syringes and in straws in a controlled-rate freezer showed no significant difference in post-thaw motility (P = 0.217) or survival (P = 0.217) after 30 min. However, after 180 min the survival rate showed a significant reduction in syringes (P = 0.045). A significant difference (P less than 0.00008) in the rate of fertilization of oocytes was seen in IVF cycles using frozen-thawed donor sperm (58/142, 42%) when compared to fresh sperm from husbands (2315/3926, 59%). A significant reduction (P less than 0.00005) in fertilization rate was also observed in the case of supernumerary oocytes in GIFT cycles with the cryopreserved donor sperm (29/132, 22%) compared to the husbands' sperm (239/514, 46%). However, the pregnancy rate following IVF and embryo replacement was the same after fertilization with fresh sperm (75/351, 21%) as opposed to frozen sperm (3/14, 21%). Furthermore, a higher pregnancy rate was observed in GIFT with frozen donor sperm (9/19, 47%) than with fresh sperm from husbands (28/103, 27%), though this was not statistically significant (P = 0.079). These results show this simplified methods of semen cryopreservation to be effective when used in an IVF and GIFT programme, giving pregnancy rates comparable to fresh normospermic semen samples. The method is simple, quick and inexpensive.

Cell Survival↗

PubMed1991

[[The tempo and quantum components in trends in period fertility measures in present-day Japan: a Butz-Ward-type model and its application]].

"This paper examined the validity of a Butz-Ward-type model by applying it to trends in Japan's fertility rates from 1968 to 1986. Most of the existing studies on the Butz-Ward model used total fertility rates as the dependent variable. As the Butz-Ward model is concerned with couples' fertility behaviors, [the author uses]...total marital fertility rates. We first calculated total marital fertility rates (TMFR) from 1968 to 1986 by using data of Japan's National Fertility Surveys.... As a result of the auto-regression analysis of TMFR, we found a statistically significant negative effect of a rise in employed wife's wage rate as was expected. As for the timing indices, the third birth timing index was significantly positively affected by an increase in husband's income when his wife was employed, while the third birth was likely to be delayed by a rise in employed wife's wage rate." An English summary is available from the author.

Asia↗

PubMed1999

Study of evaluation criteria used for in vitro bovine oocyte selection and maturation.

Production of bovine preimplantation embryos in vitro requires beneficial maturation conditions and high quality oocytes at the germinal vesicle stage. The current classification of oocytes is based on character of the cumulus cell investment around the oocyte. We wished to study the nuclear stage of immature oocytes selected for in vitro maturation according to cumulus cell character and, in the other hand, to compare the relationship among 3 parameters utilized to evaluate in vitro maturation of bovine oocytes (degree of cumulus expansion, meiotic maturation rate and in vitro fertilization rate) when fetal calf serum, steer serum and bovine follicular fluid supplementation were used. Ovaries were collected at an abattoir and the oocytes harvested. As regards selection criteria, immature oocytes were classified as Class A, B, C and D according to the character of the cumulus cells. A high percentage of Class A oocytes (87.7%) were in the germinal vesicle stage with respect to the other classes (p < 0.05). Significant differences were found in the meiotic maturation rate in Class A oocytes (76.5%) versus those of the other classes (p < 0.05). The meiotic maturation rate diminished to 47.5% when Class A oocytes were denuded and then matured in vitro (p < 0.05). As regards maturation criteria, there was no cumulus expansion when oocytes were matured in TCM-199 without supplementation, partial expansion with the addition of fetal calf serum and full expansion when supplemented with steer serum or bovine follicular fluid. No significant differences were found in the meiotic maturation rate for the various treatments. In vitro fertilization rate was significantly lower in media without supplementation versus supplemented media (p < 0.05), but no significant differences were found between the supplemented media inter se. There is no direct relationship between the three studied parameters to evaluate in vitro maturation. Class A oocytes are the most likely to mature in vitro as they not only have a close association with their surrounding cumulus cells, but are also very numerous in the germinal vesicle stage. The degree of cumulus expansion and the meiotic maturation rate have a relative importance in evaluating in vitro maturation, as oocyte maturation implies not only nuclear events but also at other cellular levels, as evaluated by in vitro fertilization.

Animals↗

PubMed1995

Effects of supplementation of the maturation media with insulin on in vitro maturation and in vitro fertilization of bovine oocytes.

This study was carried out to determine the effects of supplementation of the maturation media with insulin on in vitro maturation and fertilization of bovine oocytes. In Experiment 1, cumulus-intact bovine oocytes were cultured in a maturation medium (TCM-199 containing 10% fetal calf serum, 0.02 U/ml follicular stimulating hormone and 1 microgram/ml estradiol-17 beta) with or without insulin supplementation (10 micrograms/ml). The maturation and fertilization rates of oocytes and subsequent embryonic development to the blastocyst stage were not affected by the treatment with insulin in the presence of serum and the hormones during the maturation period. In Experiment 2, to avoid the effects of serum and the hormones, a serum- and hormone-free maturation medium (TCM-199 containing 1 mg/ml polyvinyl alcohol) was used. In the absence of serum and hormones during the maturation period, the maturation rate was not affected by treatment with insulin, but the fertilization rate was improved. In Experiment 3, when denuded oocytes were inseminated together with cumulus cells cultured in serum- and hormone-free maturation medium supplemented with insulin, the fertilization rate was increased. These results demonstrate that the addition of insulin to the serum- and hormone-free maturation medium improves the fertilization rate of bovine oocytes in vitro, and suggest that insulin may stimulate the secretion of sperm capacitating agent (s) from cumulus cells.

Animals↗

PubMed1989

Pregnancy rate is significantly higher in in vitro fertilization procedure with spermatozoa isolated from nonliquefying semen in which liquefaction is induced by alpha-amylase.

In 115 patients (group I) in which normal liquefaction of semen occurred, the fertilization rate of the yielded oocytes was 71.2% after standard in vitro fertilization procedure, and the viable pregnancy rate per patient per cycle was 13.0%. In a comparable group of 26 patients (group II), in which semen liquefaction did not occur spontaneously, alpha-amylase was added in order to liquefy the semen. In this group, the fertilization rate was 86.7% of the yielded oocytes, and the viable pregnancy rate per patient per cycle was 26.9% (P less than 0.05). It is concluded that alpha-amylase can be of use to liquefy nonliquefying semen, and that the resultant spermatozoa have a positive effect on pregnancy results.

Adult↗