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More than 90% fertilization rates after intracytoplasmic sperm injection and artificial induction of oocyte activation with calcium ionophore.

OBJECTIVE: To examine whether fertilization rates after intracytoplasmic sperm injection can be increased by artificial oocyte activation. DESIGN: Oocytes that failed to fertilize spontaneously by 24 hours after intracytoplasmic sperm injection were treated either with calcium ionophore to induce activation or with solvent only to serve as control. The ability of ionophore-treated and control oocytes to achieve delayed fertilization was compared. SETTING: Private hospital and public research center. PATIENTS: Infertile couples treated by intracytoplasmic sperm injection. INTERVENTIONS: Intracytoplasmic sperm injection. MAIN OUTCOME MEASURES: Fertilization and cleavage rates. RESULTS: The mean rate of spontaneous fertilization after intracytoplasmic sperm injection was 32%, but 88% of the oocytes that failed to fertilize spontaneously did so after subsequent exposure to calcium ionophore. Most of these oocytes underwent at least one apparently normal cleavage division. In contrast, delayed fertilization of oocytes not treated with ionophore was an exceptional finding. If only oocytes remaining intact after intracytoplasmic sperm injection are taken into account, the mean global fertilization rate of ionophore-enhanced intracytoplasmic sperm injection was 91%. CONCLUSIONS: These results show that the failure of oocyte activation is the main cause of fertilization failure after intracytoplasmic sperm injection. If an appropriate, clinically applicable treatment is found to overcome this problem, intracytoplasmic sperm injection can be expected to yield fertilization rates far exceeding those of standard IVF with normal spermatozoa.

Adult↗

A GIS-based fuzzy classification for mapping the agricultural soils for N-fertilizers use.

Special attention should be paid to the choice of the proper N-fertilizer, in order to avoid a further acidification and degradation of acid soils and at the same time to improve nitrogen use efficiency and to limit the nitrate pollution of the ground waters. Therefore, the risk of leaching of the fertilizer and of the acidification of the soils must be considered prior to any N-fertilizer application. The application of N-fertilizers to the soil requires a good knowledge of the soil-fertilizer relationship, which those who are planning the fertilization policy and/or applying it might not have. In this study, a fuzzy classification methodology is presented for mapping the agricultural soils according to the kind and the rate of application of N-fertilizer that should be used. The values of pH, clay, sand and carbonates soil variables are estimated at each point of an area by applying geostatistical techniques. Using the pH values three fuzzy sets: "no-risk-acidification"; "low-risk-acidification"; and "high-risk-acidification" are produced and the memberships of each point to the three sets are estimated. Additionally, from the clay and sand values the membership grade to the fuzzy set "risk-of-leaching" is calculated. The parameters and their values, which are used for the construction of the fuzzy sets, are based on the literature, the existing knowledge and the experimentation, of the soil-fertilizer relationships and provide a consistent mechanism for mapping the soils according to the type of N-fertilizers that should be applied and the rate of applications. The maps produced can easily be interpreted and used by non-experts in the application of the fertilization policy at national, local and farm level. The methodology is presented through a case study using data from the Amfilochia area, west Greece.

Agriculture↗

Effects of semen filtration and dilution rate on morphology and fertility of frozen gander spermatozoa.

Feces, urates or dirt originating from feathers often contaminate gander semen during collection, threatening its fertilizing ability. Seminal plasma used as a diluent has a similar effect, particularly on spermatozoa subjected to cryopreservation or short-term storage under refrigeration. The aim of the experiments was to evaluate the effects on spermatozoa motility, morphology and fertilizing ability after minimizing the influence of the contaminants by semen filtration or dilution prior to freezing. Pooled semen, collected twice a week from 9 White Italian ganders by dorso-abdominal massage, was divided into two parts. One sample was filtered and both were diluted in 1:1 or 1:0.5 (v/v) with EK diluent, equilibrated for 15 min at +4 degrees C, mixed with dimethyl-acetamide (DMA) in the final concentration 6% (v/v) and frozen to -140 degrees C in a computerized freezer, at a rate of 60 degrees C/min. In fresh and processed (filtered, freeze-thawed) semen were examined the spermatozoa motility and morphology, and fertilizing ability for freeze-thawed semen, both for unfiltered and filtered. In freeze-thawed semen no tangible differences due to experimental factors were observed in motility and percent of live spermatozoa in total. On average 35 to 42% of the spermatozoa survived the freezing process, but only 10 to 15% were normal, without any damage visible under the light microscope. The fertility of unfiltered freeze-thawed semen inseminated twice a week in a 0.2 mL dose (about 3 to 5 x 10(6) of live normal spermatozoa each) averaged 66.1% and hatchability of the set eggs 57.1 and 86.5% of the fertile eggs. The fertility obtained after the insemination with semen filtered prior to freezing was lower (64.3%), but hatchability was slightly higher (58.6 and 91.1% of set and fertile eggs, respectively). The duration of fertility for filtered semen was longer than that for unfiltered, 10 days after the last insemination the eggs were still fertile. The fertility results of freeze-thawed gander semen were very promising taking into consideration the small amount of inseminated live normal spermatozoa and it is possible to improve this result by increasing the number of spermatozoa in the insemination dose.

Animals↗

Effect of sperm capacitation and fertilization media on IVF and early embryo development of prepubertal goat oocytes.

Experiments were carried out to develop an improved IVF system for prepubertal goat oocytes matured in vitro. Cumulus oocyte complexes (COC) were obtained by slicing ovaries from slaughtered prepubertal goats. Oocytes were matured in TCM199 supplemented with 20% estrous goat serum (EGS) + 10 micrograms/mL FSH + 10 micrograms/mL LH + 1 microgram/mL estradiol 17 beta for 27 h at 38.5 degrees C in 5% CO2 in air. In Experiments 1 and 2, freshly ejaculated spermatozoa were capacitated in 1 of 3 media: TALP/H, modified Defined Medium (mDM) and mH-M199 with 50 micrograms/mL heparin for 45 min. Matured oocytes were fertilized in TALP, mDM or mH-M199 in Experiment 1 and in TALP in Experiment 2. In Experiment 3, three media were used for sperm capacitation and fertilization: Treatment A (control group): spermatozoa were capacitated in mDM with 50 micrograms/mL heparin for 45 min and fertilized in TALP medium with 1 microgram/mL hypotaurine; Treatment B: spermatozoa were capacitated in mDM with 50 micrograms/mL heparin + 388 micrograms/mL caffeine for 30 min and fertilized in TALP medium without hypotaurine; Treatment C: spermatozoa were capacitated in mDM with 50 micrograms/mL heparin for 45 min and fertilized in TALP medium with PHE (20 microM penicillamine, 10 microM hypotaurine and 2 microM epinephrine). At 24 h post insemination, the ova were transferred to a granulosa cell monolayer, and early embryo development was evaluated until Day 8. In experiment 2, the results show, that mDM plus heparin for sperm capacitation and TALP medium with hypotaurine for oocyte fertilization provided the highest proportion of penetrated oocytes, both total number (79.6%) and normal fertilization (55.1%), whereas the use of caffeine (44.6 and 31.2%, total and normal fertilization rate, respectively) and PHE (31.8 and 20.6%, total and normal fertilization rate, respectively) as motility enhancers did not improve the results obtained in the control group (48.7% and 37.2%, total and normal fertilization rate, respectively). These were no differences for the results of morulae and blastocysts.

Animals↗

Temperature related fertility selection on body size and the sex-ratio gene arrangement in Drosophila pseudoobscura.

We measured temperature-dependent fertility selection on body size in Drosophila pseudoobscura in the laboratory. One hundred single females of each of the three karyotypes involving the 'sex-ratio' (SR) and the standard (ST) gene arrangement on the sex chromosome laid eggs at either 18 or 24 degrees C. The experiment addressed the following hypotheses: (a) Fertility selection on body size is weaker at the higher temperature, explaining in part why genetically smaller flies appear to evolve in populations at warmer localities. (b) Homokaryotypic SR females are less fecund than homokaryotypic ST females, possibly mediated by the effect of body size on fertility, explaining the low frequencies of SR despite its strong advantage due to meiotic drive. The data were also expected to shed light on a mechanism for the evolution of plasticity of body size through fertility selection in environments with an unpredictable temperature regime. Hypothesis (a) was clearly refuted because phenotypically larger ST females had an even larger fertility surplus at the higher temperature and, more importantly, the genetic correlation between fertility and body size disappeared at the lower temperature. As to (b), we found that temperature affects fertility directly and indirectly through body size such that ST and SR females were about equally fecund at both temperatures, although different in size and size-adjusted fertility. We observed heterosis for both size and fertility, which might stabilize the polymorphism in nature. The reaction norms of body size to the temperature difference were steeper for ST females than for SR females, implying that fertility selection could change phenotypic plasticity of body size in a population. Selection on body size depended not only on the temperature, but also on the karyotypes, suggesting that models of phenotype evolution using purely phenotypic fitness functions may often be inadequate.

Animals↗

Relationships between sperm motility characteristics assessed by the computer-aided sperm analysis (CASA) and fertilization rates in vitro.

PURPOSE: Some studies have suggested that computer-aided sperm analysis (CASA) estimates of concentration and movement characteristics of progressively motile spermatozoa are related to fertilization rates in vitro. However, it has also been suggested that the greater number of motility parameters assessed by CASA does not imply more precision in predicting fertility. This study was carried out to investigate the relationships between the CASA estimates and fertilization rates in vitro. METHODS: Semen quality analysis was performed using CASA in 136 in vitro fertilization-embryo transfer (IVF-ET) cycles with at least 3 oocytes collected. The CASA estimates before and after swim-up were compared between 108 cycles with fertilization rate > 50% ("good" group) and 28 cycles with fertilization rate < or = 50% ("poor" group). RESULTS: Before swim-up, there were significant correlations between fertilization rates and CASA estimates, including amplitude of lateral head displacement (ALH) (r = .269), curvilinear velocity (VCL) (r = .297), straight line velocity (VSL) (r = .266), and rapid sprm movement (Rapid) (r = .243). There was also a significant correlation between the fertilization rates and straightness (STR) after swim-up (r = -0.178). As for sperm movement characteristics, there were significant differences of ALH (p < .005), VCL (p < .001), VSL (p < .005), and Rapid (p < .01) between "good" and "poor" groups before swim-up. After swim-up, there were significant differences of VCL (p < .005), average path velocity (VAP) (p < .005), and Rapid (p < .05) between the two groups. CONCLUSIONS: These results indicate that some of the CASA estimates provide reliable estimation of the fertilizing ability of human sperm. There were significant differences of the two sperm movement characteristics, including VCL and Rapid (before and after swim-up), indicating that the total distance traveled by rapid sperm movement might be important in human sperm fertilizing abilities.

Cell Size↗

Free amino acid concentration in hydatid cyst fluids from fertile and infertile human and animal Echinococcus granulosus.

The aim of this study was to search and compare free amino acid composition of fertile and infertile cyst fluids obtained from humans and animals infected naturally with Echinococcus granulosus, by using automated analysis based on cation-exchange chromatography with post-column ninhydrin derivatization system. 11 free amino acids from fertile (sheep origin), nine from infertile (cattle origin), 13 from infertile (human origin) hydatid cyst fluids and 19 amino acids from sera of patients with hydatid infection were detected. The levels of glycine, alanine, valine and lyrosine in fertile and infertile hydatid cysts fluids were significantly higher than in sera from patients with hydatid cysts. Glycine level in the fertile hydatid cyst fluids (sheep origin) was significantly higher than those of infertile cysts fluids (cattle and human origin) and sera with hydatid patients. Glycine level in fertile hydatid cyst fluids was about two times more concentrated in infertile cattle cyst fluids, 10 times more concentrated in infertile human hydatid cyst fluids and 13 times more concentrated in sera with hydatid patients. On the other hand, alanine and valine concentration in the fertile and infertile cyst fluids were at similar level with the exception that valine level in fertile cyst fluids was 12 times more concentrated in infertile human cyst fluids. The levels of tyrosine, citrulline, leucine, isoleucine and lysine amino acids in fertile and infertile hydatid cyst fluids were similar. Our findings with respect to fertile and infertile cysts fluids showed that free amino acids concentrations in cyst fluids were significantly, higher in sera from patients with hydatid cyst. Total amount of free amino acids content in fertile and infertile cyst fluids was three to eight times higher from that of human sera with hydatid patients.

Amino Acids↗

Fertility and pregnancy-related events in women with celiac disease: a population-based cohort study.

BACKGROUND & AIMS: Previous studies have raised concern about reduced fertility and increased adverse pregnancy-related events in women with celiac disease, but none has estimated overall fertility compared with the general female population. METHODS: We compared computerized primary care data for 1521 women with celiac disease with data for 7732 age- and practice-matched women without celiac disease. We estimated population-based rates of fertility and adverse pregnancy outcomes. RESULTS: Crude fertility rates were 48.2 and 47.7 live births per 1000 person-years for women with and without celiac disease, respectively (rate ratio, 1.01; 95% confidence interval, 0.90-1.14). Age-specific fertility rates showed that women with celiac disease had lower fertility when younger but higher fertility when older compared with women without celiac disease. This increase in relative fertility with increasing age held whether women had treated or untreated celiac disease. Risks of cesarean section (odds ratio, 1.33; 95% confidence interval, 1.03-1.70) and miscarriage (rate ratio, 1.31; 95% confidence interval, 1.06-1.61) were moderately higher in women with celiac disease, but risks of assisted birth, breech birth, preeclampsia, postpartum hemorrhage, ectopic pregnancy, stillbirth, and termination were similar. CONCLUSIONS: Overall, women with celiac disease have fertility similar to that of the general female population, but they have their babies at an older age. Although our findings may reflect a disease effect, the age shift in fertility rates and the increase in cesarean section risk is consistent with socioeconomic or educational advantages of women with celiac disease.

Abortion, Spontaneous↗

Effect of continuous intrauterine administration of prostaglandin F2 alpha and indomethacin on fertilization of rabbits.

The effect of continuous intrauterine administration of prostaglandin F2 alpha (PGF2 alpha) or indomethacin or indomethacin together with PGF2 alpha and PGE2 or vehicle on fertilization of rabbits was studied. These substances and vehicle were delivered into the cornua of the uterus via an Alzet minipump for 11 days. The animals were inseminated vaginally. Compared with controls (104 eggs of which 88.5% were fertilized) a reduction of the fertilization rate was observed with indomethacin (74 eggs of which 70% were fertilized). Exogenously added PGF2 alpha did not change the fertilization rate. The administration of indomethacin together with PGE2 raised the fertilization rate to 86% (63 eggs of which 54 were fertilized). The application of PGF2 alpha together with indomethacin showed a fertilization rate of 85% (59 eggs of which 50 were fertilized). The indomethacin application was associated with a reduction of prostaglandin production in several tissues from the female genital tract, showing that indomethacin is taken up by the endometrium of the rabbit. The ovary, oviduct, cervix and vagina were mainly affected by this treatment. The route of transport of this drug is not known, however. The reduction of the total number of eggs together with the decrease of the fertilization rate after indomethacin administration point towards multiregional sites of interference of prostaglandins in reproductive functions. PGF2 alpha seems to be the more important factor since PGE2 may be converted to PGF2 alpha in reproductive tissues.

Animals↗

Reducing the risk of multiple births by transfer of two embryos after in vitro fertilization.

BACKGROUND: In vitro fertilization is associated with a high risk of multiple births, which is a direct consequence of the number of embryos transferred. However, other factors that contribute to the risk are not well defined. METHODS: Using the data base established by the Human Fertilization and Embryology Authority in the United Kingdom, we studied the factors associated with an increased risk of multiple births in 44,236 cycles in 25,240 women. The factors included the woman's age, the cause and duration of infertility, previous attempts at in vitro fertilization, previous live births, number of eggs fertilized, and number of embryos transferred. RESULTS: Older age, tubal infertility, longer duration of infertility, and a higher number of previous attempts at in vitro fertilization were all associated with a significantly decreased chance of a birth and of multiple births. Previous live birth was associated with an increased chance of a birth but not of multiple births. The higher the number of eggs fertilized, the higher the likelihood of a live birth. When more than four eggs were fertilized, there was no increase in the birth rate for women receiving three transferred embryos as compared with those receiving two, but there was a considerable increase in the rate of multiple births when three were transferred (odds ratio, 1.6; 95 percent confidence interval, 1.5 to 1.8). CONCLUSIONS: Among women undergoing in vitro fertilization, the chances of a live birth are related to the number of eggs fertilized, presumably because of the greater selection of embryos for transfer. When more than four eggs are fertilized and available for transfer, the woman's chance of a birth is not diminished by transferring only two embryos. Transferring more embryos increases the risk of multiple births.

Adult↗

Sperm preparation for intracytoplasmic injection: methods and relationship to fertilization results.

Sperm preparation for intracytoplasmic sperm injection (ICSI) is described and the effect of high speed centrifugation during preparation on fertilization rate is evaluated. No significant differences were found in the 2-pronuclear or abnormal fertilization rates between sibling oocytes injected with sperm prepared by swim-up or mini-Percoll combined with high speed centrifugation. The high fertilization rate obtained with both methods indicates that high speed centrifugation is not necessary to prepare sperm for ICSI. Fertilization rates were also compared for sperm obtained from ejaculates, fresh and frozen epididymal aspirates, and testicular biopsies. High fertilization rates were obtained from all groups but they were significantly higher in those oocytes injected with epididymal sperm (78% per oocyte surviving injection). The high fertilization rate with epididymal sperm may reflect sperm quality or may result from the method of sperm preparation for injection. Fertilization after the injection of sperm from which the tail was dislodged during immobilization was compared with that obtained using intact sperm. A significantly lower rate of 2-pronuclear fertilization was found in those oocytes injected with sperm heads only (55%) compared with intact sperm (68%), although cleavage rates between the two groups were similar. The use of hypo-osmotic medium to select potentially live sperm from an immotile sample is also described and fertilization was obtained after the injection of sperm with a structural defect which were selected using this technique. These results indicate that high fertilization rates can be obtained with ejaculated, epididymal and testicular sperm without special treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Separation↗

Population growth and fertility patterns in an Old Order Amish settlement.

BACKGROUND: Since they are a healthy and well-nourished isolate with strong religious proscriptions against birth control, the fertility patterns of the Old Order Amish have long been studied by demographers, particularly those with an interest in natural fertility. AIM: The present report describes population growth, population structure, and fertility patterns in a little-studied Amish settlement located in northeastern Ohio, USA (Geauga Settlement). SUBJECTS AND METHODS: A directory prepared by the Geauga Settlement provides data on the dates of birth of the mother, father, and all children for 1337 families for the period up to 1 January 1993. This information was used to assess population size, population structure, fertility rates, age at marriage, age of mothers at first and last birth, and birth intervals. Estimates of total settlement size were also derived from an older directory covering the period up to 1 January 1988 and a recently published directory which covers the period up to 1 January 1998. RESULTS: The settlement consisted of 7546 individuals in 1988, 8345 individuals in 1993, and 9572 individuals in 1998. The completed marital fertility rate was 7.7 (SD 3.6) births per woman. Total fertility rate decreased by about one birth between 1909 and 1967, in association with a change in fertility patterns, with women born in more recent cohorts tending to have more of their offspring at an earlier age, both of which suggest the existence of behaviours to control fertility. On the other hand, the age at the birth of the last child remained fairly constant over this time period. CONCLUSIONS: There is some suggestion of fertility control by Amish families. However, this control appears to be independent of parity, suggesting that there is no intention to limit family size. It is therefore reasonable to conclude that the Amish in the Geauga Settlement are a natural fertility population.

Adult↗

Use of census data for construction of fertility history for Danish women.

BACKGROUND: Modern epidemiology increasingly uses data on families. The authors constructed an extended fertility database for women born in Denmark from 1930 onwards by supplementing the existing Fertility Database with household data from the 1970 census. METHODS: A fertility history was constructed for all women participating in the 1970 census, but aiming for complete data only for women aged 20-39. The fertility history of these women prior to the 1970 census was constructed from the census data including 1,648,813 persons coded as children. An algorithm was used transforming household information into fertility history data by matching women and children according to family position. Children for whom the algorithm gave no match were searched for in the Fertility Database; children not found in the Fertility Database either were searched for manually. The fertility history after the 1970 census was retrieved from the Fertility Database. RESULTS: Using data from the census 1970, 98.5% of the children were linked to a mother, and 99.6% of these links were estimated to be correct, corresponding to 98.1% of the children being linked correctly. In total, 964,720 children of women aged 20-39 in 1970 were identified, which was equivalent to 96.6% of the expected live-born children, and to 99.1% of the expected surviving children. CONCLUSION: Census household data proved to be an excellent data source for construction of fertility histories.

Adult↗

Metabolic similarities between fertilization and phagocytosis. Conservation of a peroxidatic mechanism.

At the time of fertilization, sea urchin eggs release a peroxidase which, together with H2O2 generated by a respiratory burst, is responsible for hardening of the fertilization membrane. We demonstrate here that the ovoperoxidase of unfertilized eggs is located in cortical granules and, after fertilization, is concentrated in the fertilization membrane. Fertilization of sea urchin eggs or their parthenogenetic activation with the ionophor A23187 also results in (a) the conversion of iodide to a trichloroacetic acid-precipitable form (iodination), (b) the deiodination of eggs exogenously labeled with myeloperoxidase and H2O2, (c) the degradation of thyroxine as measured by the recovery of the released radioiodine at the origin and in the inorganic iodide spot on paper chromatography, and (d) the conversion of estradiol to an alcohol-precipitable form (estrogen binding). The iodination reaction and the binding of estradio occurs predominantly in the fertilization membrane where the ovoperoxidase is concentrated. From the estimation of the kinetics of incorporation of iodine, we determine that the peroxidative system is active for 30 min after fertilization, long after hardening of the fertilization membrane is complete. Most of the bound iodine is lost during the hatching process. Iodination of albumin is catalyzed by the material released from the egg during fertilization, when combined with H2O2 and iodide. Iodination, thyroxine degradation, and estradiol binding are inhibited by azide, cyanide, aminotriazole, methimazole, ascorbic acid and ergothioneine, all of which can inhibit peroxidase-catalyzed reactions. These responses of the sea urchin egg to fertilization are strikingly similar to the changes induced in polymorphonuclear leukocytes by phagocytosis and, in both instances, a peroxidative mechanism may be involved.

Animals↗

Relationship between human in-vitro fertilization and intracytoplasmic sperm injection and the zona-free hamster egg penetration test.

The zona-free hamster egg penetration test (HEPT) is widely used for evaluating the fertilizing ability of human spermatozoa. However, the relationship between the HEPT and microassisted fertilization has yet to be determined. To evaluate the efficiency of HEPT in selecting the most appropriate method of in-vitro fertilization (IVF), including intracytoplasmic sperm injection (ICSI) in couples with male factor infertility, clinical laboratory data was analysed retrospectively. The patients were divided into groups according to the sperm penetration index as determined by the HEPT: group A (sperm penetration index = 0), group B (sperm penetration index < 15) and group C (sperm penetration index > or = 15). A total of 405 oocytes were collected and inseminated by conventional methods in 69 couples with male factor infertility. In all, 31 out of 148 (20.9%) oocytes fertilized in group A; 35 out of 117 (29.9%) in group B; and 73 of 140 (52.1%) in group C. The clinical pregnancy rates per transfer in groups A, B and C were 0% (0/13), 0% (0/14) and 25.9% (7/27) respectively. Both the fertilization rate and pregnancy rate in group C was significantly higher than in groups A and B. ICSI was carried out in a total of 57 couples and 334 oocytes in metaphase II stage were manipulated. The normal fertilization (2 pronuclear) rate per oocyte was 65.6 +/- 26.0% (mean +/- SD). Out of 127 oocytes, 76 (59.8%) fertilized in group A, 57 out of 87 oocytes (65.5%) in group B and 86 out of 120 oocytes (71.7%) in group C. Of the 56 transfers, 17 clinical pregnancies were obtained, giving an average pregnancy rate of 30.4% per transfer. The clinical pregnancy rates per transfer in groups A, B and C were 17.4% (4/23), 40.0% (4/10) and 39.1% (9/23) respectively. No significant differences were observed in the fertilization rates or in the pregnancy rates between the three groups. In addition, there were no differences in the fertilization and pregnancy rates between the ICSI and IVF patients in group C. These findings suggest that the results of the HEPT are well correlated with the fertilizing ability of human spermatozoa in the patients treated by conventional IVF. Couples suffering from male factor infertility with a sperm penetration index of < 15 (as determined by HEPT) should consider treatment with ICSI, while those with a sperm penetration index of > or = 15 should attempt conventional IVF.

Animals↗

Differential evaluation of human sperm hypoosmotic swelling test and its relationship with the outcome of in-vitro fertilization of human oocytes.

The hypoosmotic swelling test is a simple laboratory test to measure the functional integrity of the human sperm membrane. Its in-vivo and in-vitro applicability needs to be evaluated before it can be accepted as a useful routine test for the fertilizing potential of human semen. We studied the standard semen analysis results and differential sperm tail swelling patterns of seminal and swim-up sperm after hypoosmotic treatment in 97 semen samples used for in-vitro fertilization of human oocytes. Semen samples were classified as infertile (0% fertilization rate; n = 27) or fertile (greater than 0% fertilization rate; n = 70) before statistical analyses. There was a significant difference (P less than 0.005) in percentage normal morphology of seminal sperm between the fertile and infertile semen samples. The percentage normal morphology of seminal sperm correlated (r = 0.4250; P less than 0.005) with the in-vitro fertilization rate of human oocytes and this parameter was selected by the multivariate stepwise discriminant analysis as the discriminator capable of predicting the in-vitro fertilization rate with 57.7% accuracy. The percentage total swelling of seminal and swim-up sperm after hypoosmotic treatment was not correlated with the in-vitro fertilization rate. The percentage swelling pattern g (the open type) of seminal sperm was also selected by the multivariate stepwise discriminant analysis as the discriminator to predict the in-vitro fertilization rate. This parameter correlated with the percentage normal morphology of seminal sperm (r = 0.3014; P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Membrane↗

The prognosis for assisted conception treatment after unexpected failure of fertilization in vitro: a comparative study.

The relative prognosis for further assisted conception treatment (without micro-injection) after initial unexpected failure of fertilization in apparently favourable couples undergoing in-vitro fertilization (IVF) treatment was assessed. After their first cycle of treatment, 481 consecutive couples were grouped according to their fertilization (including cleavage) rate per oocyte into five bands. Proportions of couples proceeding to further cycles of treatment by IVF or gamete intra-Fallopian transfer (GIFT) and resulting fertilization and pregnancy rates were compared. Pregnancy rates in the first cycle of treatment were significantly related to fertilization rate. The fertilization rate was zero in 13 couples (3%) and only 1-24% in 18 (4%). There were no significant differences between these groups in the proportions proceeding to further treatment (31, 50%) compared with others (overall 37%, including some treated by GIFT), or in their median fertilization rates (75, 60% compared with 67%--IVF cycles only), pregnancy rates (20, 38% of cycles compared with 37%--IVF or GIFT) or birth rates (20, 38% of cycles compared with 31%--IVF or GIFT). Amongst couples whose initial fertilization rate was > or = 50% there was no fertilization in 4% of subsequent IVF cycles. We conclude that in couples with well defined favourable conditions, including tests of sperm function for assisted conception treatment, who have unexpected failure of fertilization, the prognosis for further treatment remains favourable without resort to more complex investigations or micro-injection methods. Such failure occurs infrequently and generally as a random event, and should have no appreciable effect on life-table calculation of cumulative pregnancy and birth rates in this group of patients.

Fertilization in Vitro↗

Sperm concentration and the fertilization of human eggs in vitro.

The effect of sperm concentration on the fertilization of preovulatory and immature human eggs was studied in the context of an ongoing in vitro fertilization-embryo transfer (IVF-ET) program. Fertilization success was independent of the follicular recruitment protocol used, and with preovulatory eggs, was inversely related to sperm concentration over the range of 2.5 - 50 X 10(4) motile sperm/ml. Maximum fertilization (80.8%) occurred at a concentration of 2.5 X 10(4) motile sperm/ml. The incidence of polyspermic fertilization was directly related to the sperm concentration, decreasing from 5.5% at 10 X 10(4) to 0% at 1-2.5 X 10(4) motile sperm/ml. Immature eggs cultured in vitro, then inseminated, also demonstrated an inverse relationship between fertilization and sperm concentration with a maximum fertilization rate of 66.6% at 5 X 10(4) motile sperm/ml. The percentage of motile sperm in the inseminating population had no influence on fertilization rates unless the value dropped below 40%. Fertilization success using sperm from oligospermic and polyzoospermic males was also examined. In contrast to males with normal semen parameters, oligospermic males demonstrated highest fertilization success at 50 X 10(4) motile sperm/ml. The IVF of preovulatory eggs using sperm from polyzoospermic males was comparable to that for males with normal semen parameters at equivalent sperm concentrations. The implications of these findings to the application of IVF-ET technology to the infertile couple is discussed.

Embryo Transfer↗