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PubMed1986

[Fertilization results in superovulated ewes and goats after transmural-intrauterine insemination controlled by laparoscopy].

A comparative experiment in oestrous synchronized and superovulated ewes and does is described on which fertilization was studied following natural mating or transmural intrauterine insemination by laparoscopy. Thirty-two ewes were inseminated into each uterine horn with 50-100 microliter of fresh undiluted semen, whereas 26 ewes were mated by fertile rams. Fertilization rates of eggs recovered 5-7 days later were 93.7% (163/174) and 60.5% (78/129) respectively. Eight does were inseminated by laparoscopy while 12 does were mated by fertile bucks. Numbers of eggs fertilized of those recovered 6-7 days later were 42/47 (89.4%) in the intrauterine inseminated group and 51/60 (85%) in the naturally mated group. These results indicate that high levels of fertilization can be obtained in ewes following intrauterine insemination with fresh semen with the aid of a laparoscope and that it is possible to overcome the reduced fertilization rates after natural mating. In contrast to the ewe the intrauterine semen deposition in does did not improve the high fertilization rates obtained after natural mating.

Animals↗
PubMed1980

The effect of benzo(a)pyrene on fertility, primordial oocyte number, and ovarian response to pregnant mare's serum gonadotropin.

The polycyclic aromatic hydrocarbon (PAH) benzo(a)pyrene (BP) reduced the fertility of DBA/2N mice in a dose-dependent fashion. Control mice produced offspring at a rate of 0.91 pups/mouse per week. Treatment with BP at doses of 10, 100, 200, and 500 mg/kg decreased offspring production rates to 0.61, 0.20, zero and zero pups/mouse per week, respectively. BP also destroyed primordial oocytes in similarly treated mice. Treatment with BP at doses of 10, 50, 100, and 500 mg/kg destroyed 20%, 58%, 88%, and 100%, respectively, of the primordial oocytes in DBA/2N mouse ovaries. Dose-response curves for fertility reduction and primordial oocyte destruction were identical. The threshold for fertility reduction was 3.4 mg/kg and for primordial oocyte destruction it was 2.7 mg/kg. The 50% effect doses for fertility reduction and primordial oocyte destruction were 25.5 mg/kg and 24.5 mg/kg, respectively. Although BP reduced fertility and destroyed primordial oocytes, it had no effect on the ovarian weight response to pregnant mare's serum gonadotropin (PMSG), consistent with the observations that BP at these doses does not destroy growing or preovulatory oocytes or follicles. The similarity of the dose-response curves for fertility reduction and primordial oocyte destruction suggested that their mechanism of action is similar and resides within the ovary. As BP had no effect on ovarian response to PMSG, the effect was likely to reside outside the regulatory mechanisms controlling ovulation. These data suggest that the site of fertility reduction by BP may reside in the mechanisms of fertilization, implantation, or early conceptus development.

Animals↗
PubMed1982

[Economic problems and contradictions in mineral fertilizer application for solving nutrition problems in the developing countries].

The optimum application of mineral fertilizers in the agriculture of the developing countries is inhibited by the monopolization of the mineral fertilizer industry in the capitalist economic world system and the numerous contradictions in the developing countries themselves. Thus it requires the full state sovereignty and economic independence of the developing countries, and the creation of such social conditions which enable the further extension and better utilization of the fertilizer capacities as well as the optimum fertilizer application. This means applying mineral fertilizers in the best possible way in order to ensure the nutrition of their own population and aiming at agrarian structures which promote mineral fertilization, restructuring the system of mineral fertilizer prices, and developing the mineral fertilizer service.

Developing Countries↗
PubMed1983

Genetic and phenotypic correlations between duration of fertility and certain traits in Alexandria and Fayoumi chickens.

Two Alexandria lines selected for a high (HL) or low (LL) eight-week body weight, and an unselected Fayoumi line were used to study the duration of fertility, fertility percentage, fertility percentage duration, age at sexual maturity, egg number in the first ninety days of laying, egg weight, eight-week body weight, and body weight at sexual maturity. The fertility could be improved through selection for duration of fertility. Within the lines, early mature pullets had a longer duration of fertility than those matured later. The duration of fertility within the lines is a rather good indicator of eight-week body weight. Within the lines, the duration of fertility increases with the increase in body weight at the age of sexual maturity.

Animals↗
PubMed1995

Fertilization and pregnancy with acrosome intact sperm by intracytoplasmic sperm injection in patients with disordered zona pellucida-induced acrosome reaction.

OBJECTIVE: To determine whether fertilization and pregnancy could be obtained by injection of acrosome-intact sperm into the cytoplasm in patients with persistent failure of fertilization in IVF-ET associated with disordered zona pellucida (ZP)-induced acrosome reaction (AR). DESIGN: Sperm-ZP binding and penetration and ZP-induced AR were compared between patients and fertile donors. Acrosome-intact sperm removed from the ZP were injected into the cytoplasm of the oocytes. SETTING: Reproductive Biology Unit, Royal Women's Hospital. MAIN OUTCOME MEASURES: The proportion of ZP penetrated and ZP-induced AR and fertilization and pregnancy after intracytoplasmic sperm injection were analyzed. RESULTS: Most (7/8) of the patients had consistently normal sperm characteristics including concentration, motility and velocity, acrosomes, and morphology. Mean number of sperm bound to the ZP was not significantly different between patients (97 sperm/ZP) and fertile donor controls (100 sperm/ZP). However, AR of sperm bound to the ZP was significantly lower in the patients (4%) than in controls (61%). None of the ZP (n = 32) were penetrated by patient sperm whereas all (n = 32) ZP were penetrated by control sperm. Acrosome intact sperm removed from the ZP were used for intracytoplasmic sperm injection. All patients had > or = 50% normal fertilization and embryo development. Three pregnancies (one early aborted, two ongoing) were achieved after the transfer of fresh or frozen embryos. CONCLUSION: Acrosome-intact human sperm can produce a high fertilization rate and pregnancies after intracytoplasmic sperm injection in patients with disordered ZP-induced AR. The acrosome reaction is unlikely to be important for fertilization with intracytoplasmic sperm injection.

Acrosome↗
PubMedDate not supplied

The ethane dimethanesulfonate-induced decrease in the fertilizing ability of cauda epididymal sperm is independent of the testis.

Several decades ago it was reported that when adult male rats were exposed to a single injection of 50 mg/kg body weight ethane dimethanesulfonate (EDS) and mated with untreated females, average litter size was significantly reduced as early as 2 weeks later. Recently, we demonstrated that EDS exerts multiple effects in the epididymis of adult rats. Some of these effects were independent of reduced serum testosterone (T) levels. Later we found that EDS has direct effects on epididymal epithelial cells in vitro. Herein, we sought to determine whether EDS perturbs the fertilizing ability of cauda epididymal sperm. Four days after exposure to 50 mg/kg EDS, sperm from the proximal cauda epididymidis were inseminated into adult receptive females in utero; on the next day the percentage of fertilized eggs was determined. Exogenous T administration and castration were used to determine what role, if any, androgen deprivation and the testis had on the fertilizing ability of proximal cauda epididymal sperm. Sperm motion parameters, serum T, T in the caput/corpus epididymidis, and detergent-extracted sperm protein were evaluated and correlated with fertilizing ability. We found that both castration and EDS exposure significantly compromised the fertilizing ability of sperm in proximal cauda epididymidis 4 days after exposure. Exogenous T, sufficient to maintain serum T, completely restored the fertilizing ability of sperm following castration, but not after EDS exposure. Moreover, exogenous T failed to restore fertilizing ability when castrated animals were exposed to EDS. Thus, the effects that EDS exerts on sperm maturation in vivo are independent of the testis. Finally, the only endpoint that was well correlated with fertilizing ability was the relative amount of an acidic 18-kDa sperm protein.

Animals↗
PubMed1977

Binding of concanavalin A to the surface of sea urchin eggs and its alteration upon fertilization.

The binding of concanavalin A (Con A) to Strongylocentrotus purpuratus eggs has been investigated using 125I-concanavalin A (125I-Con A). The lectin binds specifically to the egg surface and does not produce agglutination of the eggs. High 125I-Con A concentrations are necessary to saturate all of the surface binding sites. Scatchard plots of the binding data are biphasic and may be interpreted as showing two main classes of sites. Unfertilized eggs have 4 X 10(8) high affinity sites/egg (Ka=8 X 10(-7) M) and 4.5 X 10(8) istes of lower affinity (Kb=4 X 10(-6) M). The sites may be assigned to different layers of the egg surface by studying the effects of removal of egg coats on the binding reaction. Removal of the jelly coat by washing eggs at pH 4.5 has no effect on binding. However, disruption of the vitelline layer with dithiothreitol leads to a decrease in the number of high affinity sites. After fertilization, the high affinity sites are found upon the fertilization membrane produced from the vitelline layer. Low affinity sites predominate in the plasma membrane, and are not affected by treatments which alter the vitellinelayer. The number of low affinity sites double upon fertilization, with the insertion of new membrane into the egg surface, as a result of cortical granule exocytosis. The doubling of sites is not due to hyaline material released from the cortical vesicles at fertilization, and thus these sites appear to reside upon the new membrane that is inserted from the cortical vesicles. If eggs are activated with ammonia, bypassing the cortical reaction, no change in the binding of ConA occurs. Con A inhibits fertilization at concentrations higher than 0.1 mg/ml, where less than 50% of the high affinity (viteline layer) binding sites are occupied, and there is little binding to the low affinity (plasma membrane) sites. Thus, the interaction of sperm with vitelline layer components may be an obligatory step in the fertilization process. A fraction of the 125I-Con A binding sites is cleaved from the egg surface upon fertilization or after activation by the calcium ionophore A23187. This release of Con A binding sites occurs during the limited proteolysis of surface components that accompanies the cortical reaction, and does not occur with ammonia activation of the egg, where the cortical reaction does not occur. Thus, the changes in Con A binding at fertilization are caused by the massive cortical granule exocytosis that occurs within minutes of sperm penetration, and not by activation of the egg per se.

Animals↗
PubMed1977

Relative income and fertility.

The present study examines the relationship between relative income (i.e., actual income in relation to the expected income of one's socioeconomic group) and fertility, using data collected by the 1967-1968 Canadian Family Growth Study (Balakrishnan et al., 1975). We broaden the tests of relative income beyond cumulative fertility to spacing behavior and then examine some of assumptions included in the relative income model of fertility. Results of the tests, in brief, are as follows: (a) Relative income is found to be more closely related to spacing than to cumulative fertility; and (b) the relationship between relative income and fertility is strongest among those couples who plan their life ahead and have a high level of education and occupation, and when temporal alignment is brought between the measures of relative income and fertility. For the relative income model to receive confirmation, it was specified that the following hypotheses must be confirmed: (a) that fertility behavior would vary positively with relative income but the fertility norm would show no relationship with relative income: and (b) that consumption norms and behavior would show no relationship with relative income. The outcome of these tests are in the expected direction, giving support to the relative income model. In addition, there is some evidence of predictive capability of the relative income model for correlative behavior.

Birth Rate↗
PubMed1996

The ionic basis of membrane potential changes from before fertilization through the first cleavage in the egg of the frog Rana cameranoi.

Experiments were performed to identify the ionic basis of membrane potential changes in the Rana cameranoi egg, from prior to fertilization through the first cleavage. The membrane potential was monitored continuously during this period. Ten per cent Ringer was used as the recording solution in the control group. The effects of Na+ or Ca2+ conductances were observed by altering external concentrations of these ions. K+ and Cl- conductances were tested by adding channel blockers of these ions (TEA and SITS, respectively) to the extracellular medium. The resting potential of the unfertilized egg is mainly affected by K+ conductance. Chloride conductance is responsible for the depolarization phase of the fertilization potential evoked by sperm entry, and K+ conductance is responsible for the repolarization phase of this potential. We suggest that Na+ permeability does not directly contribute to the fertilization potential; however fertilization potential peak is significantly reduced upon a reduction of extracellular sodium. The fertilization potential is not significantly influenced by extracellular Ca2+, and eggs fertilized in calcium-free solutions maintain their normal development; these results suggest that extracellular Ca2+ does not significantly contribute to the electrical and mechanical blocks that prevent polyspermy. The membrane potential of the fertilized egg does not alter significantly until the first cleavage. Potassium conductance contributes to hyperpolarization generated upon the first cleavage, whereas sodium is the basic ion responsible for the phase which follows peak hyperpolarization, and which plays a role in the return of the post-cleavage membrane potential to a steady level. Cl- conductance, which is important as the ionic basis of the fertilization potential, does not significantly influence any parameter of the cleavage cycle.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1976

Reproductive performance and fertility testing in strain 13 and Hartley guinea pigs.

A study to test the effects of certain experimental manipulation on the reproductive capacity of male guinea pigs required verifying the fertility of the male guinea pigs before and after manipulation. Methods of testing fertility were evaluated, and normal reproductive data from preexperimental and control groups were tabulated and analyzed. No data from the actual experiments were included. Virgin and proven fertile males were mated with 1 (1:1) or 2 (2:1) virgin or proven fertile females. Inbred (13/N Umm) and conventional (Mfi:CFDH-ML (DH) ) guinea pigs were used. Ninety-five percent of both groups of males were fertile. Eighty-four percent of both groups of females were fertile. Male guinea pigs previously proven fertile had the same subsequent fertility rate as virgin males. Over one-third of the conceptions did not take place during the first estrus cycle (16 da) during which the males and females were mated. Strain 13 and Hartley females had litters of approximately the same size (3.1 vs 3.0), but the neonatal mortality was statistically lower (P less than 0.001) in the Hartley stock (9.3%) than in the Strain 13 guinea pigs (28.4%).

Animals↗
PubMed1994

Fertilization and in vitro development of cryopreserved human prophase I oocytes.

OBJECTIVE: To determine the potential for in vitro maturation, fertilization, and cleavage after cryopreservation of immature, prophase I human oocytes. DESIGN: Immature oocytes obtained in excess of the number required by the patient were randomized and cryopreserved at the prophase I stage or cultured as control. After thawing and maturation in vitro, test and control oocytes were inseminated with husband's sperm and evaluated for fertilization and cleavage in vitro. SETTING: In vitro fertilization program. PATIENTS: Consenting patients undergoing controlled ovarian hyperstimulation for the purposes of IVF. MAIN OUTCOME MEASURES: Rates of maturation to metaphase II, fertilization, and cleavage were compared between control and cryopreserved oocytes. RESULTS: Upon thaw, 58.5% (72/123) of prophase I oocytes were viable. Control oocytes demonstrated a 74.8% (98/131) maturation rate to metaphase II, a 56.5% (52/92) fertilization rate, and an 11.5% (6/52) blastocyst rate. Cryopreserved oocytes showed a 83.3% (60/72) rate of maturation, a 57.7% (30/52) fertilization rate, and a 3.3% (1/30) blastocyst rate. No significant differences were noted between any of these parameters. CONCLUSIONS: These results demonstrate that prophase I oocytes from stimulated IVF cycles are able to survive cryopreservation and resume meiosis to achieve full nuclear maturation post-thaw. In addition, cryopreserved oocytes retain the same capacity for fertilization and development as control oocytes.

Adult↗
PubMedDate not supplied

Age-specific incidence and prevalence rates of treated epilepsy in an unselected population of 2,052,922 and age-specific fertility rates of women with epilepsy.

BACKGROUND: There are no data on prevalence or incidence of treated epilepsy, and no data on fertility of women with epilepsy from an unselected UK population. METHODS: We used the General Practice Research Database to ascertain the incidence and prevalence of people with treated epilepsy in an unselected population of 2,052,922 people in England and Wales, and also age-specific fertility rates. We defined period prevalence of treated epilepsy as the number of people with epilepsy taking an antiepileptic drug per 100,000 people during 1995. The incidence of treated epilepsy was defined as the number of new cases of treated epilepsy per 100,000 people during the same period. We calculated fertility rates among women with treated epilepsy between 1991 and 1995 and compared these rates with the population rates for England and Wales in 1993. FINDINGS: The period prevalence of treated epilepsy in 1995 was 5.15 per 1000 people (95% CI 5.05-5.25). The prevalence was lower in children (age 5-9 years 3.16 [2.86-3.48]; 10-14 years 4.05 [3.70-4.42]), and higher in older people (65-69 years 6.01 [5.50-6.57]; 70-74 years 6.53 [5.97-7.14]; 75-79 years 7.39 [6.73-8.11]); 80-84 years 7.54 [6.78-8.39]; 85 years and older 7.73 [6.98-8.66]). The incidence of treated epilepsy was 80.8 per 100,000 people (76.9-84.7). The incidence was lower in children (5-9 years 63.2 [50.5-79.1]; 10-14 years 53.8 [42.4-68.3]) and higher in older people (65-69 years 85.9 [68.5-107.3]; 70-74 years 82.8 [65.0-105.2]; 75-79 years 114.5 [116.9-179.2]; 80-84 years 159 [125.2-202.6]; > or = 85 years 135.4 [100.4-178.7]). Fertility was lower among women with treated epilepsy, with an overall rate of 47.1 livebirths per 1000 women aged 15-44 per year (42.3-52.2), compared with a national rate of 62.6 in the same age-group. The standardised fertility ratios were significantly lower between the ages of 25 and 39 years in women with epilepsy (p<0.001). INTERPRETATION: Compared with previous studies, we found that the incidence of epilepsy was higher in elderly people and lower in children. The prevalence rates also increase with age. Women aged 25-39 years with treated epilepsy have significantly lower fertility rates than those in the general population. Research is needed to identify any potentially preventable causes for the low fertility rates.

Adolescent↗
PubMedDate not supplied

Proximate determinants of fertility in Nigeria.

Data from the 1981-82 Nigeria Fertility Survey (NFS) are used to identify the key proximate determinants of fertility in Nigeria. The patterns of their individual and collective effects are analyzed in a search for possible sources of fertility change. Exposure to the risk of childbearing through first marriage is found to be the most important proximate determinant of Nigerian fertility. Subsequent to marriage, fertility is determined mainly by breastfeeding and postpartum sexual abstinence. Where fertility shows significant socioeconomic variations, there are equally identifiable patterns of the impact of the proximate determinants which explain these differentials to a large extent. On a national scale, the observed patterns of the impact of the measured proximate determinants do not appear to suggest that Nigerian fertility is soon to experience a large decline.

Adolescent↗
PubMedDate not supplied

Effects of multi-family housing on marital fertility in Iran: population policy implications.

The hypothesis of the relationship between housing types and fertility, which was originally developed and tested in Bogota, Colombia's housing study, is reexamined using Iranian data of urban married women of reproductive age. The findings of the study clearly and consistently show that women living in single-family housing units have significantly higher actual and desired fertility than women living in multi-family housing units, regardless of their major social, economic and demographic differences. Furthermore, the analysis of the relative effects of socioeconomic and demographic variables on fertility indicate that housing types have greater effects on fertility than wife and husband's level of education, when the effects of other variables are controlled. This study implies that crowding and density, which generally are the outcome of high fertility, do have feedback effects causing fertility to decline. This provides some evidence for the hypothesis of self-generating fluctuations in population growth which maintains that a large population will face stiff economic competition, lower incomes, congestion and crowding if other means of production as well as social infrastructure do not expand simultaneously. Finally, this study suggests an optimistic sign of fertility reduction in the large urban populations where the single-family housing units are being replaced by multi-family housing units mainly because of high cost of land, material, and labor, and the shortage of housing units. Most of the large cities in Iran today fit the above descriptions.

Adult↗
PubMedDate not supplied

Changes in fertility relative to starting, stopping, and spacing behaviors in a migrating Mennonite community, 1775-1889.

Fertility change over time in a migrating Mennonite church congregation is reconstructed through genealogies developed from church registries of vital events during 1725-1924. The congregation was located in Prussia from 1725-1821, in Russia from 1822-1874, and in Kansas, U.S.A., from 1875-1924. Age-specific marital fertility rates were relatively low and usually peaked for women aged 25-29. Total fertility rates ranged from 1.19 to 5.29. These relatively low figures for a natural fertility population may partly reflect underreporting of births and deaths of infants, but it also reflects the heterogeneity in fertility evident for this population. Some women had many children while others were having either few or none. This pattern changed twice. Fertility was lowest during residence late in Prussia and early in Russia, peaked during residence late in Russia, and has decreased slightly for women born in the United States.

Birth Intervals↗
PubMedDate not supplied

Prospects and programs for fertility reduction, 1990-2015.

What is the likelihood that each of the 37 developing countries with populations of 15 million or more in 1990 will reach replacement fertility by the year 2015? These countries have a combined population of 3.9 billion, 91 percent of the population of all developing countries. For this article, a composite index was used as the basis for predicting future levels of total fertility. The index was constructed from socioeconomic variables (life expectancy at birth, infant mortality rates, percent adult literacy, ratio of children enrolled in primary or secondary school, percent of the labor force in nonagricultural occupations, gross national product per capita, and percent of the population living in urban areas), total fertility rates for the years 1985-90, total fertility rate decline from 1960-65 to 1985-90, family planning program effort scores in 1989, and the level of contraceptive prevalence in 1990. Eight countries are classified as certain to reach replacement fertility by 2015, and an additional thirteen probably will also. Five countries are classified as possibly reaching replacement fertility, and eleven as unlikely to do so.

Birth Rate↗
PubMed1991

Behavioural and biological determinants of fertility transition in sub-Saharan Africa.

In the transition from high to low fertility, different biological and behavioural proximate determinants play roles of varying importance in mediating the change. In most regions of the world, the practice of contraception has come to play the major role, so much so that there is a close relationship worldwide between the level of practice of contraception and the level of fertility. In sub-Saharan Africa, the prevalence of contraceptive practice is low, and fertility levels are exceptionally high for recorded levels of contraceptive practice, even where levels of contraceptive practice are comparable to other regions. The discrepancies are explained to a very large extent by differences between Africa and other regions in other proximate determinants--notably exposure to the risk of pregnancy, and abstinence after delivery. It would seem that transition in African countries will follow one of two patterns that are different to the pattern of transition observed in all other regions. First, fertility may rise before it declines, due to abandonment of traditional fertility regulation for some time prior to the eventual adoption of contraceptive practice. Second, the prevalence of contraceptive practice may rise for a time before there is an observable decline in fertility, because at the same time that contraception is adopted, traditional regulation of fertility is being abandoned, offsetting any effect on fertility. Kenya is an example of the first pattern, while Botswana, Ghana, and Zimbabwe are probably examples of the second.

Africa↗
PubMed1997

Experimental mate switching in pied flycatchers: male copulatory access and fertilization success

By making female birds pair successively with different males, and analysing the paternity of the eggs laid, it is possible to examine how a male's success in obtaining fertilizations is determined by the timing of his copulatory access to the female. Such an experiment is reported here with pied flycatchers, Ficedula hypoleucaMate switching was induced at different stages within the female's fertile period by removing the resident male. The paternity of the clutch was analysed by microsatellite DNA typing. Removed males had full paternity in the clutch if they were removed as late as after the second egg was laid (day 1), and they lost all paternity if they were removed more than 1 day before the first egg was fertilized (less than day -2). Male switching during the period day -2 to day 1 always resulted in mixed paternity in the clutch. Males that were paired to the female for only a few (1-3) days during this period achieved on average more than one fertilization per access day, with a peak on day -1. Thus, assuming that the timing of observed pair bonds reflects the timing of each male's copulatory access to the female, the first eggs in the laying sequence were fertilized by inseminations occurring shortly before the time of fertilization, whereas the last eggs were fertilized by inseminations taking place several days prior to their fertilization. Our documentation of the most important period for copulatory access has some important implications for understanding sexual behaviour in this species.

Journal Article↗