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PubMed1987

Cannabinoids reduce fertility of sea urchin sperm.

Cannabinoids are potent pharmacological substances derived from marihuana. The effects of delta 9-tetrahydrocannabinol (THC), cannabinol (CBN), and cannabidiol (CBD) on fertilization in the sea urchin Strongylocentrotus purpuratus were investigated. Insemination of THC-treated eggs (5-400 microM) with excess sperm did not result in polyspermic fertilization. At minimal sperm densities, THC (0.1-10 microM) inhibited fertilization in a dose-dependent manner. Pretreatment of eggs with THC did not reduce their receptivity to sperm. Pretreatment of sperm with THC reduced their fertilizing capacity. The concentration of THC required to reduce sperm fertility by 50% was 1.1 +/- 1.1 microM. The fertilizing capacity of THC-treated sperm depended on concentration of sperm and duration of pretreatment. The fertility of sperm at minimal densities was reduced by 50% at 129.3 +/- 43 s treatment with 10 microM THC. The adverse effect of THC on sperm fertility was reversible. CBN and CBD at comparable concentrations (0.1-10 microM) inhibited fertilization in a manner similar to THC. First division was not delayed in zygotes that were fertilized with sperm pretreated with 10 microM THC. These studies show that cannabinoids directly affect the process of fertilization in sea urchins by reducing the fertilizing capacity of sperm.

Animals↗
PubMed1995

Pretransition marital fertility variation over time: was there deliberate control in England?

An important line of research concerning historical fertility patterns in currently developed countries of Europe has concluded that, prior to the fertility transition, marital fertility was essentially constant over time, and deliberate fertility control was virtually unknown. It has been argued that variations over time in overall fertility were largely the consequence of variations in nuptiality. Other researchers have challenged these views and present evidence for the existence of a significant minority of fertility controllers in pretransition populations. In this article, we find support for this second view and argue that (1) there was significant, non-random variation in marital fertility over time, prior to the transition; (2) in many cases, this variation in marital fertility was large relative to contemporaneous variations in nuptiality; and (3) in a substantial minority of the cases, the variation over time in pretransition marital fertility was so large that it is suggestive of deliberate fertility control. Thus, our findings question the view of fertility transition as an innovation in deliberate marital fertility control. While most of our evidence is based on data from England and Wales, we find corroboration of our key results in other European data.

Family Planning Services↗
PubMedDate not supplied

Site-specific phosphorus application based on the kriging fertilizer-phosphorus availability index of soils.

Site-specific phosphorus management is done to optimize crop production and minimize P loss from soils. The spatial variability of the available P prior to fertilizer application and the P-fixation tendency of soil both need to be taken into account for variable-rate P application. The objectives of this research were to document the spatial variability of the fertilizer-P availability index, which shows the P-fixation tendency, and to develop a strategy that takes the spatial distribution of this index into account for site-specific phosphorus application. In this study, the spatial patterns of the fertilizer-P availability index were characterized by using geostatistics. The ordinary kriging was used for spatial interpolation of the fertilizer-P availability index. Because the fertilizer-P availability index of soil is related to oxalate-extractable Fe and Al and because measuring oxalate-extractable Fe and Al is much easier than directly determining the fertilizer-P availability index, the spatial distribution of the fertilizer-P availability index can be obtained using the oxalate-extractable Fe and Al data. The spatial distribution of Olsen-extractable P, which was used to measure the available-P status prior to fertilizer-P application, was also estimated by using ordinary kriging. The required fertilizer-P amounts were then determined using the kriging estimates of the fertilizer-P availability index and Olsen-extractable P. A fertilizer-P recommendation map for the 430-ha study site in Changhua county, Taiwan was generated by using this approach for illustration. The proposed method for generating fertilizer-P recommendation maps can be used for variable-rate application to maintain an adequate P status for crop production and to potentially reduce the P loss from soils.

Agriculture↗
PubMed2006

Proteins of the cauda epididymal fluid associated with fertility of mature dairy bulls.

We evaluated the relationships between proteins in cauda epididymis fluid (CEF) and fertility scores of dairy bulls. Fertility was expressed as the percentage point deviation (PD) of bull nonreturn rate from the average fertility of all bulls at an artificial insemination center. The number of services for each bull ranged from 1074 to 52 820, and PD values ranged from +7.7% to -6.6%. CEF from 20 bulls was obtained from vasa deferentia cannulae and was separated from sperm by centrifugation immediately after collection. Samples were evaluated by 2-dimensional (2-D) sodium dodecyl sulfate polyacrylamide gel electrophoresis gels stained with Coomassie blue, and polypeptide maps were analyzed by PDQuest software. Protein quantities, defined as the total integrated optical density of the spots, were compared between groups of high-fertility sires (n = 12; PD >or= 0) and low-fertility sires (n = 8; PD < 0) and were also used as independent variables in regression analysis. Proteins were identified by capillary liquid chromatography-nanoelectrospray ionization-tandem mass spectrometry. An average of 118 spots was detected in 2-D maps of the CEF, but we were unable to distinguish any protein that was expressed only in high-fertility or in low-fertility bulls. However, the amount of alpha-L-fucosidase 2 and cathepsin D was 2.3- and 2.4-fold greater (P < .05) in high-fertility than in low-fertility bulls, respectively. Conversely, the intensities of 3 isoforms (24-27 kd; pl 6.3-5.8) of prostaglandin D-synthase (PGDS) were from 3.2- to 2.2-fold greater in low-fertility sires (P < .05). An empirical regression model established that a significant proportion (R(2) = 0.72; P < .0001) of the variation in fertility scores (PD values) was explained by the intensities of cathepsin D and 1 isoform of PGDS (24 kd; pl 6.3). Thus, multiple proteins present in the CEF are potential biomarkers of fertility in high-use, mature Holstein bulls.

Animals↗
PubMed2005

Late fertility in Europe: some comparative and historical data.

THE ISSUE: Given the substantial increase in late fertility (at ages 35 and older) in the last few years in Western countries, the paper raises the question of what factors have caused this new trend, and how likely it is to continue. METHODS: Late fertility is measured using the sum of age-specific fertility rates at 35 or more; its contribution to the total fertility rate (in % of the total fertility rate) and the proportion of first childbirths in this fertility is then computed. Late fertility among men is assessed using the same method, where the necessary data are available. The data analysed sometimes date back to the 18th century for women (Sweden), and the early 20th century for men (in France). RESULTS: Late fertility is now much lower than it used to be. Despite the current increase--which can be traced back to the early 1980s for most Western countries, and appears to be much more recent and limited in the former socialist countries--current levels are very low compared with those of the past, among men as well as women. Reduced family size was the main factor in that decline, which became more pronounced as a result of women having a first child at younger ages. The reversal of the trend is due only to postponed childbearing, which must be viewed as part of a general trend towards postponement of all demographic events. More and more of the children born in such circumstances are thus first children. Very late fertility (at 40 or more) has increased, though only slightly, for men as well as women, and age 45 seems to be a limit beyond which few are prepared to have children. Social norms concerning the age limit for a person to have a child could account for the differences from one country to another in that respect. CONCLUSION: Late fertility is likely to continue increasing as long as fertility continues to decrease among young people. However, the increase will continue to be due mostly to the "younger" age groups (under 40 for women, under 45 for men); both biological constraints and social norms probably play a part in the stagnation of very late fertility levels.

Adult↗
PubMed1984

Census-derived estimates of fertility by duration since first marriage in the Republic of Korea.

This paper estimates ever-married birth rates by age and duration since first marriage and ever-married total fertility rates for the Republic of Korea, derived by applying an extension of the own-children method of fertility estimation to the 1975 and 1980 censuses. Since each census provides annual estimates for the 15-year period previous to enumeration, there is a ten-year period of overlapping estimates that facilitates checks for consistency and accuracy. Comparisons are also made with estimates derived from the 1974 Korea National Fertility Survey, which was part of the World Fertility Survey. The method works well, except in its application to the 1975 Census where the evidence suggests considerable misreporting of age at first marriage because of the way the question was asked and coded. Results confirm that ever-married fertility fell substantially in Korea between 1961 and 1980, with a temporary resurgence in the late 1960s and early 1970s. Ever-married fertility rose at younger ages and shorter durations and fell at older ages and longer durations. Ever-married fertility differentials by urban-rural residence and by education were usually in the expected direction, with urban fertility generally lower than rural fertility and the fertility of those with more education usually lower than the fertility of those with less education. Differential ever-married fertility by urban-rural residence and education declined over the estimation period.

Adolescent↗
PubMed1995

Fertility index analysis in cryptorchidism.

We report on 226 male patients with cryptorchidism 6 months to 16 years old who underwent open testis biopsy at orchiopexy or orchiectomy at Children's Hospital and Health Center from 1986 to 1990. A total of 355 specimens was obtained. Tissues were preserved in Bouin's solution and examined on light microscopy for fertility index measurements. Several biopsies prepared using Bouin's preserved paraffinized tissue and glutaraldehyde preserved semi-thin cut tissue were found to have comparable fertility index measurements. Of 184 patients with unilateral undescended testes 87 also underwent biopsy on the contralateral descended testis. A total of 42 patients had bilateral undescended testes. Age matched comparisons were made between fertility index measurements of the undescended testes and those previously reported of normal testes. Additional case matched comparisons of fertility indexes were made in those children who underwent biopsy of the undescended testis and its descended mate. Statistical analysis was performed using the independent Student t-test. When comparing undescended to descended testes, there was no significant difference in the fertility index of patients 1 year old or younger but fertility index differences were statistically significant in all of the other age groups. Fertility index measurements were significantly decreased from normal expected values in all age groups with unilateral cryptorchidism and in all but the 13 to 18-month-old group with bilateral cryptorchidism. The fertility index in the descended testis was similar to previously reported normal testis measurements in boys between 13 months and 6 years old. Our data suggest that potential fertility in the cryptorchid testis may be significantly impaired compared to normal testicular fertility regardless of patient age at the time of discovery of the undescended testis. The fertility index of the descended mates of unilateral undescended testes may also be somewhat impaired in certain age groups. Orchiopexy in the first year of life may be indicate to preserve available fertility potential.

Adolescent↗
PubMed1993

Analysis of human in vitro fertilization failure.

Fertilization failure is a serious problem in human in vitro fertilization (IVF) programs and deserves further investigation and management. Two hundred and ninety-four IVF cycles performed at the National Taiwan University Hospital from July 1989 to June 1991 were retrospectively analyzed. Thirty-seven (13%) of the 294 cycles were observed to have fertilization failure. The incidence of fertilization failure in male factor patients was significantly higher (p < 0.05) than in others. Patients with oligoasthenospermia tended to have a higher rate of fertilization failure than patients with oligospermia or asthenospermia alone. In non-male factor patients, a smaller number of oocytes and mature oocytes was found in patients with fertilization failure than in patients achieving fertilization. Sperm penetration assay (SPA) using zona-free hamster eggs was performed for 15 patients with fertilization failure; no correlation was found between SPA and the fertilizing ability of the sperm in vitro. Four patients with severe oligoasthenospermia had repeated fertilization failure in subsequent IVF cycles. The other five patients, including four non-male factor patients and one male factor patient, achieved fertilization in their second IVF trial. Our results suggest that severe oligoasthenospermic patients with repeated fertilization failure should be candidates for micromanipulation of gametes in subsequent IVF trials.

Female↗
PubMed1996

[Elucidation of the mechanism of fertilization and clinical application of assisted reproductive technology].

Fertilization is the process including many events such as maturation of egg and sperm, attachment, binding, acrosomal reaction, penetration, fusion, cortical reaction, zona reaction and nuclear fusion of both gamete, whereby individual gametes from the female and male unite to create offspring. Although the reason for mechanism of fertilization is still not clearly understood, this process may accelerate the rate adaptation in evolution. In this special lecture, I would like to present our experimental and clinical results especially concerning with morphological, physiological, biochemical and molecular approach on the mechanism of fertilization. 1. Development and maturation of follicles and oocytes. It is well known that pituitary FSH, LH control the ovarian function. Follicular development and ovum maturation are also controlled by both pituitary gonadotropins and local factors such as autocrine and paracrine agents. When hMG is injected during 1-6 day of menstrual cycle, several dominant follicles are developed. If hMG is injected after selection of dominant follicles, only one dominant follicle develop in the ovary. When PMS-treated immature rats were injected with immature or mature follicle fluids, rats injected with mature follicular fluid showed strongly suppress in the ovarian weights and numbers of ovulated follicles. Also mature follicle suppress aromatization from and androstenedione to estradiol. These findings mean that mature follicular fluid contains inhibitory factors. Apoptosis of granulosa cells and follicular steroids are related to fertilization. 2. Intracellular calcium of oocyte. Intracellular calcium concentration is known to start to increase in a periodic manner after fertilization in oocytes of mammalians. In 65% of tested mouse oocytes, fertilization occurred during 4 hours observation after sperm insemination in vitro. An initial long lasting intracellular calcium concentration was observed and followed by periodic manner. This calcium oscillation is inhibited by calcium blockers such as verpamil and nifedipine, but increased by high concentration of extracellular calcium concentration in the medium. Role of increase of intracellular calcium are understood to prevent polysperm and activate metabolism of oocytes. 3. Glucose metabolism of oocytes. Mouse embryo utilizes pyruvate as an essential nutrient until the 8-cell stage, and glucose thereafter. We have devised non-radiometrie and enzymatic microassay method to measure glucose, deoxyglucose, deoxyglucose 6-phosphate incorporated into individual mouse oocytes and preimplantation embryo. In parallel, the activities of several enzymes of glycolytic pathway were also determined. In this study, glucose metabolism is necessary to develop in fertilized ova with changing activity of enzymes. 4. Molecular bases of ovarian fluid. The zona pellucida ZP is involved in a number of events in fertilization, all these fertilization events occur in the oviduct. Oviductal glycoprotein 200-240 KD has been identified from oviductal zona pellucida. Monoclonal antibody of oviductal glycoprotein reacted with ZP of oviductal egg but not with the ovarian egg. Anti-ZPO antibody inhibit to bind sperm to ZP. Sequences in mouse and hamster oviduct specific glycoprotein are estimated, this glycoprotein mRNA was observed in only oviduct by northern blotting method. These molecular gene expression was observed by in situ hybridization in the oviduct of estrous cycle of hamster. 5. Microinsemination of sperm. Microinsemination of sperm into oocyte is widely used in clinical medicine. Sperm penetration assay (hamster test) is useful method to estimate fertilization capacity of sperm. But immotile sperm cannot estimate it. So modified micro sperm penetration assay was established to estimate fertilization capacity of sperm by using micro-manipulator. Subzonal sperm injection (SUZI) and intracytoplasmic sperm injection (ICSI) promotes fertilization and cleavage rate in immotile

Animals↗
PubMedDate not supplied

Discriminant analysis indicates a single sperm protein (SP22) is predictive of fertility following exposure to epididymal toxicants.

In a previous study, we found that ethane dimethanesulphonate (EDS) compromised the fertilizing ability of proximal cauda epididymal sperm from the rat within 4 days of exposure, an effect that persisted in castrated, testosterone (T)-implanted animals, establishing direct action on the epididymis. This EDS-induced reduction in fertilizing ability was highly correlated with a quantitative decrease in specific sperm protein. Here we sought to determine whether the fertility of proximal cauda epididymal sperm recovered from animals exposed to a variety of male reproductive toxicants could be predicted by assessing quantitative changes in specific sperm protein(s), or whether more common endpoints (e.g., sperm motility, sperm morphology, serum and epididymal tissue T, cauda epididymal sperm reserves) also are required to predict fertility. Intact adult male rats were dosed with EDS (25 or 50 mg/kg), chloroethylmethanesulphonate (CEMS; 12.5 or 18.75 mg/kg), or epichlorohydrin (EPI; 3 or 6 mg/kg) daily for 4 days. Castrated, T-implanted rats were dosed with hydroxyflutamide (HFLUT; 12.5 or 25 mg/kg) daily for 5 days. On day 5, proximal cauda epididymal sperm were inseminated in utero into receptive, cervically stimulated adult females, and on day 9, fertility (implants/corpora lutea) was assessed. Fertility-was decreased by the higher dose of each toxicant (P < 0.05) and also by the lower dose of EPI and HFLUT. Likewise, an acidic 22 kDa sperm protein (SP22) was decreased quantitatively (P < 0.05) in silver-stained two-dimensional gels by the higher dose of each toxicant as well as by the lower dose of EPI and HFLUT. Although sperm motility and serum T were altered by specific exposures, these endpoints were not useful in predicting fertility. In contrast, SP22 was highly correlated (P < 0.0001; r2 = 0.83) with fertility. Indeed, the amount of SP22 correctly predicted 90% and 94% of the fertile (> 50% fertility) and subfertile (< 50 fertility) animals, respectively, when discriminant analysis was performed. Thus, the amount of SP22 in a cauda epididymal sperm sample may be a useful predictor of fertility in toxicant-treated animals.

Animals↗
PubMed1998

Effects of endometrial stromal cells and peritoneal fluid on fertility associated with endometriosis.

Endometriosis is one cause of infertility. The disease causes severe non-bacterial inflammation and adhesion in the ovarian tubes and/or referred reproductive organs, but a number of types of unexplained infertility without severe organic disorders also exist. In the present study, we investigated the effects of endometrial stromal cells (SC) and peritoneal fluid (PF) in endometriosis on the fertilization and embryonic development rates using mouse ova and embryos. In addition, we prepared endometriosis artificially in rats and investigated the effects of peritoneal perfusate on the fertilization and embryonic development rates. We also investigated the in vitro fertilization rate in these rats. The mouse ova, sperm, and two-cell embryos were cultured on SC isolated surgically from patients with uterine myoma (M) or endometriosis (E), and 24 hours later, the fertilization and embryonic development rates were investigated. To this co-culture system, PF from M or E patients was added, at varying concentrations, and the fertilization and embryonic development rates were investigated. Then, rats with experimental endometriosis were prepared. After confirmation of the presence of lesions, peritoneal perfusate was added, at varying concentrations, to the co-culture system, and the fertilization and embryonic development rates were investigated. In addition, the in vitro fertilization rate was investigated in these rats. Both the fertilization rate and the embryonic development rate were significantly lower for the co-culture system in the E group. In the PF addition system, PF decreased the fertilization and embryonic development rates at lower concentrations in the E group. In rats with artificial endometriosis, peritoneal perfusate from rats with lesions significantly decreased the fertilization and embryonic development rates at lower concentrations. The in vitro fertilization rate was significantly lower in rats with lesions. The above results strongly suggested that inhibitions of fertilization and embryonic development induced by SC and PF, and altered quality of the ovum itself, might be responsible for infertility in endometriosis.

Animals↗
PubMed1990

Determinants of fertility control in Korea.

The objective of this study is to examine the socioeconomic and intervening determinants of fertility control in Korea. The conceptual framework applied here is based on the synthesis framework of fertility control developed by Easterlin and Crimmins. The data came from the 1974 Korean National Family Survey, which was conducted as part of the World Fertility Survey. The study focuses on the relative importance of the socioeconomic factors and intervening variables in the determination of fertility control. The most interesting finding is that there are only small differentials in fertility control by socioeconomic factors. The analysis emphasizes the importance of examining the determinants of fertility control in terms of the intervening variables, which include the components of natural fertility, desired family size, and costs of fertility control. These intervening variables provide general support for the theoretical predictions. Moreover, most of the coefficients for these variables are statistically significant at the .05 level. The analysis also shows that motivation for fertility control is an important factor in determining use of fertility control.

Age Factors↗
PubMed1991

Identifying the fertile phase of the human menstrual cycle.

The identification of the human fertile phase as the time during which a woman or a couple may conceive is elusive. The fertile time depends on many factors in each individual menstrual cycle and may be said to be more of a statistical than a physiological entity. This paper reviews the application of statistical methods to three areas related to conception and the fertile phase. The first is the prediction and detection of ovulation from serial measurements, such as hormones, basal body temperature and cervical mucus, throughout the menstrual cycle. Typically, such variables increase from some baseline level to a peak around ovulation (the most fertile time), then subside to low levels in the postovulatory phase. The statistical challenge is to detect the rise (signalling the onset of potential fertility) and subsequent fall. Analytic methods considered include thresholds, Bayesian change-point models and particularly the cumulative sum (cusum) technique which is both simple to apply and understand, and effective. The second area comprises appropriate methods of analysing and interpreting data from clinical studies of the fertile phase, especially in so-called natural family planning (NFP) where it is usual for women to observe several indices of potential fertility. Such studies usually try to establish the temporal relationships between markers of the fertile phase and examine the success of different combinations of markers in delineating the fertile time in comparison with a standard 'defined' phase, for example, the interval from three days before to two days after the peak of luteinizing hormone. The third area is the assessment of the probability of conception on certain days of the cycle, which is vital to the understanding of the fertile phase and its application to NFP. Direct estimation of such probabilities is impractical; instead, resort must be made to estimation by maximum likelihood of the parameters of specially constructed models. Suitable models are described. Finally, the need for a new prospective study of the probability of conception in relation to the markers of the fertile phase used in the symptothermal method of NFP is discussed.

Female↗
PubMed2004

Fertility awareness-based methods for contraception.

BACKGROUND: "Fertility awareness-based methods" (FAB) of family planning "involve identification of the fertile days of the menstrual cycle, whether by observing fertility signs such as cervical secretions and basal body temperature, or by monitoring cycle days. FAB methods can be used in combination with abstinence or barrier methods during the fertile time" (WHO 2000). Several names have been used to describe this approach to contraception, including "rhythm," "natural family planning" and "periodic abstinence." Fertility awareness-based methods can be used with abstinence from sexual intercourse. Alternatively, they can be used with barrier contraceptives or withdrawal during presumed fertile times. OBJECTIVES: We retrieved and analyzed all randomized controlled trials that examined any fertility awareness-based methods used for contraception. SEARCH STRATEGY: We searched the computerized databases Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, POPLINE, EMBASE, and LILACS (each from its inception to January, 2004) for randomized controlled trials of fertility awareness-based methods. We examined the reference list of each trial as well as that of review articles. SELECTION CRITERIA: We included all randomized controlled trials in any language that compared any fertility awareness-based methods for contraception with a placebo; another method, including an alternative fertility awareness-based method; or fertility awareness-based methods used in conjunction with another contraceptive. DATA COLLECTION AND ANALYSIS: We assessed all titles and abstracts found for inclusion. We evaluated the methodological quality of the trials for potential biases by qualitatively assessing the study design; randomization method; allocation concealment; blinding; premature discontinuation rates; and loss to follow-up rates. Because of methodological weaknesses, we could not enter the trial results in RevMan, calculate measures of association, or aggregate data. MAIN RESULTS: Because of poor methods and reporting, pregnancy rates could not be determined. A trial in Colombia found similar numbers of pregnancies among women randomized to the ovulation and symptothermal methods. In contrast, a companion trial in Los Angeles observed more pregnancies in the group assigned to the ovulation method. In the two U.S. trials, recruitment of participants was unexpectedly difficult; this aspect was not mentioned in the report from Colombia. Continuation rates were poor. In the two larger trials, most participants discontinued their assigned method before entering the observation phase of the trial. REVIEWERS' CONCLUSIONS: The comparative efficacy of fertility awareness-based methods of contraception remains unknown. Despite intensive training and ongoing support, most participants in these trials discontinued prematurely. Contraceptive methods should be properly evaluated, preferably in randomized controlled trials, before adoption and dissemination.

Awareness↗
PubMed1992

The fertilization antigen-1 does not have proteolytic/acrosin activity, but its monoclonal antibody inhibits sperm capacitation and acrosome reaction.

OBJECTIVE: To determine if human sperm surface fertilization antigen exhibits proteolytic or acrosin activity and to investigate the mechanism(s) whereby monoclonal antibody (mAb) to fertilization antigen inhibits human sperm penetration of zona-free hamster ova. DESIGN: Proteolytic and acrosin activities of human fertilization antigen were determined. Acrosomal status, acrosin activity, and motion characteristics were evaluated after incubation of human sperm with immunoaffinity-purified mAb to fertilization antigen. SETTING: Academic research environment. PARTICIPANTS: Fertile donors used as controls for infertile patients for fertility evaluation. INTERVENTIONS: Human spermatozoa were treated with mAb to fertilization antigen and induced to undergo acrosome reaction using calcium ionophore A23187. MAIN OUTCOME MEASURES: Proteolytic and acrosin activities of fertilization antigen. Sperm penetration assay, acrosomal status, and motion parameters. RESULTS: Fertilization antigen does not exhibit proteolytic or acrosin activity; however, its mAb completely blocks human sperm penetration of zona-free hamster ova. The mAb to fertilization antigen inhibits ionophore-induced acrosome reaction and blocks development of the hyperactivated state of human sperm cells. CONCLUSIONS: Monoclonal antibody to fertilization antigen blocks fertilization by inhibiting capacitation and acrosome reaction.

Acrosin↗
PubMed2001

Sperm morphology, motility, and concentration in fertile and infertile men.

BACKGROUND: Although semen analysis is routinely used to evaluate the male partner in infertile couples, sperm measurements that discriminate between fertile and infertile men are not well defined. METHODS: We evaluated two semen specimens from each of the male partners in 765 infertile couples and 696 fertile couples at nine sites. The female partners in the infertile couples had normal results on fertility evaluation. The sperm concentration and motility were determined at the sites; semen smears were stained at the sites and shipped to a central laboratory for an assessment of morphologic features of sperm with the use of strict criteria. We used classification-and-regression-tree analysis to estimate threshold values for subfertility and fertility with respect to the sperm concentration, motility, and morphology. We also used an analysis of receiver-operating-characteristic curves to assess the relative value of these sperm measurements in discriminating between fertile and infertile men. RESULTS: The subfertile ranges were a sperm concentration of less than 13.5 x 10(6) per milliliter, less than 32 percent of sperm with motility, and less than 9 percent with normal morphologic features. The fertile ranges were a concentration of more than 48.0 x 10(6) per milliliter, greater than 63 percent motility, and greater than 12 percent normal morphologic features. Values between these ranges indicated indeterminate fertility. There was extensive overlap between the fertile and the infertile men within both the subfertile and the fertile ranges for all three measurements. Although each of the sperm measurements helped to distinguish between fertile and infertile men, none was a powerful discriminator. The percentage of sperm with normal morphologic features had the greatest discriminatory power. CONCLUSIONS: Threshold values for sperm concentration, motility, and morphology can be used to classify men as subfertile, of indeterminate fertility, or fertile. None of the measures, however, are diagnostic of infertility.

Adult↗
PubMed1997

Growth and water relations of Eucalyptus marginata (jarrah) stands in response to thinning and fertilization.

We studied the effects of five thinning treatments (T1 = 5.5, T2 = 11, T3 = 16.5, T4 = 22.5 and T5 = 28.5 m(2) ha(-1) basal area under bark) x two fertilizer treatments (F0 = unfertilized and F1 = fertilized with 400 kg ha(-1) N plus 229 kg ha(-1) P) on growth and water relations of pole-sized Eucalyptus marginata J. Donn ex Sm. trees growing in southwestern Australia. Thinning reduced leaf area index (LAI) from 2.1 in the T4 and T5 treatments to 0.8 in the T1F0 treatment. Fertilizer had no effect on LAI in the T2, T4 or T5 treatments, but increased LAI by 45 and 20% in the T1 and T3 treatments, respectively. Thinning plus fertilizing increased diameter growth most in the fastest growing trees, from 0.4 cm year(-1) for trees in the T5F0 and T5F1 treatments to 0.7 and 1.2 cm year(-1) for trees in the T1F0 and T1F1 treatments, respectively. In both fertilizer treatments, stand basal area and volume growth increased with increasing stand density up to 15 m(2) ha(-1), and thereafter declined with increasing stand density, such that the growth rate of trees in the T5 treatment was only half of that at a stand density of 15 m(2) ha(-1). In response to fertilizer, growth rates of the slowest and fastest-growing trees increased from 0.35 and 3.5 m(2) ha(-1) year(-1) (F0) to 0.56 and 5.4 m(3) ha(-1) year(-1) (F1), respectively. Stand growth efficiency (growth per unit LAI) increased in response to thinning, and fertilizer increased stand growth efficiency at all stand densities. Throughout the dry season, T5 trees had lower predawn shoot water potentials (Psi(pd)) (minimum of -1.5 MPa) than T1 or T2 trees (minimum of -0.7 MPa). Fertilizer decreased Psi(pd) in T5 trees (by -0.9 and -1.5 MPa, respectively, in F0 and F1), but not in T1 or T2 trees. Stand growth rate was closely related to cumulative midday water stress (CMWS) over the dry season, and volume growth rate declined sharply from 6 m(3) ha(-1) year(-1) at a CMWS of 130 MPa days, to zero at a CMWS of 220 MPa days. Application of fertilizer to thinned stands increased LAI, stand growth efficiency and stand growth. In unthinned stands, fertilizer increased stand growth efficiency and stand growth; however, it also increased tree water stress, which limited the fertilizer-induced increases in LAI and growth. We attribute the increase in tree and stand growth in response to application of fertilizer to increased photosynthetic rates, increased allocation to stem wood, and in thinned stands also to higher LAIs.

Journal Article↗
PubMed1988

Comparison of heterospermic and homospermic inseminations as measures of male fertility.

This study attempted to determine a basis for the previously observed greater sensitivity of heterospermic tests when compared to homospermic tests for detecting differences in fertility between males. In theory, the results of heterospermic tests are an indication of the proportion of eggs fertilized per unit time whereas results of homospermic inseminations measure only the cumulative or final proportion of eggs fertilized. The fertilizing ability of sperm from males of CF1 and C57BL/6N strains of mice was compared homospermically using both relatively high and low concentrations of sperm and by measuring the proportion of eggs penetrated per unit of time. The fertilizing ability of sperm from these strains was also compared using heterospermic inseminations. When females were inseminated with a high concentration of sperm, males of both strains fertilized a high and indistinguishable percentage of eggs when examined after 30 hr. When females were inseminated with either a low concentration of sperm or when the proportion of eggs penetrated was measured at 5 hr, differences between strains of mice were distinguishable. Heterospermic insemination further magnified the observed difference between strains. The results of this study confirm that measuring the percentage of eggs fertilized per unit of time can enhance the magnitude of differences between males in fertility as compared to measuring only the final percentage of eggs fertilized. Measuring the percentage of eggs fertilized per unit of time does not, however, entirely account for the large differences observed between fertility of males when they are compared using heterospermic inseminations.

Animals↗