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PubMed1991

An overview on biological markers in reproductive and developmental toxicology: concepts, definitions and use in risk assessment.

Reproduction and development are complex couple-dependent processes. Risk assessment for these health outcomes requires the use of biomarkers to link exposures to disease. Biological markers of susceptibility, external dose, internal dose, biologically effective dose, early or late biological responses, altered reproductive or developmental function, and reproductive or developmental disease are introduced. Using these biomarkers it is possible to define a biologically based risk assessment methodology for reproductive and developmental toxicity. Risk assessment for reproductive toxicity requires definition of male and female fecundity, couple-specific factors, spontaneous abortion rate, and other factors. Using using sperm count as a biomarker for male fecundity, an example of a reproductive risk assessment using biomarkers is performed.

Biomarkers↗

PubMed1990

Behavioural responses affecting gilt and sow reproduction.

Behavioural responses can have direct effects on reproduction when the performance of the behaviour contributes to productivity (e.g. achievement of copulation). Alternatively, there are indirect effects where a behavioural change is insufficient to allow adaptation to an environmental change and so the animal has to resort to physiological mechanisms with potential adverse effects on productivity. Boar contact has substantial effects on a number of female behaviours that can directly affect her productivity. Either daily introduction to a boar or continuous housing adjacent to boars is effective in stimulating the onset of oestrus in weaned sows. In addition, daily boar contact is necessary to maintain ovarian activity in post-pubertal gilts. The efficiency of the back-pressure test (BPT) in detecting sexually receptive females depends on females receiving intense and close boar contact at the time of testing. However, there are situations in which continuous stimulation from boars may adversely affect sexual behaviour; continuous housing of gilts adjacent to boars, with a wire-mesh division separating them, reduces the efficiency of detection of oestrus by means of the BPT or a boar. There is some evidence to indicate that housing weaned sows adjacent to boars may adversely affect the duration of oestrus but not detection rate of oestrus. The effects of female contact on productivity are generally indirect with physiological responses (rather than behavioural responses) to suboptimal group size, space allowance or housing system predominantly responsible for any adverse effects on reproduction. The literature on the effects of individual or group housing on reproduction is equivocal, but there is a trend for a reduced conception rate or pregnancy rate in individual housing. Group size and space allowance may affect the efficiency of detection of oestrus. A space allowance of 1 m2/animal appears to affect detection of oestrus adversely for gilts, probably via a chronic stress response associated with overcrowding. The literature on the effects of group size on sexual behaviour of female pigs is also equivocal, perhaps because in some studies there were suboptimal space allowances. Nevertheless, there appear to be problems with detection of oestrus in very small groups and in large groups. The effects of human contact on female reproduction are indirect. There are no direct effects on the sexual behaviour of female pigs and the effects on reproduction are probably mediated by a chronic stress response. High levels of fear of humans may depress the reproductive performance of pigs and this fear response is probably affected by the behaviour of the stockperson.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMedDate not supplied

[Comparative characteristics of the sex steroid content in the blood plasma of the big-mouthed buffalo, silver carp and channel catfish during reproduction].

A radioimmunoassay was to determine the content of estrogens, progestins and androgens in the blood plasma of female and male big-mouthed buffalo, silver carp and canal sheatfish before reproduction and in the first two species during reproduction as well. It was shown that sexual hormones of all 3 groups were present in the blood of males and females of the species under study, the androgen concentration being significantly higher than the estrogen and progestin content in species of both sexes. Sexual dimorphism in the estrogen and androgen content in the blood of the fishes before reproduction was revealed. An exception was a silver carp with the absence of sex differences in the androgen content. There were no significant differences in the initial progestin levels in the species of both sexes. Sex differences in the time-course of gonadal hormones during reproduction were revealed: an increase in the level of steroids of all 3 groups was observed during ovulation in females, that of androgens and progestins only in females of the studied species excluding silver carp. No increase in the concentration of androgens was observed in male silver carps during reproduction. In spite of the general regularities of the time-course of sexual steroids in the reproduction of the studied species of fish significant specific differences were noted in the absolute values of sexual hormone concentrations.

Androgens↗

PubMed1984

Clinical application of scanning electron microscopy in human reproduction.

The state of the art of scanning electron microscopy in the field of human reproduction and the clinical significance of SEM techniques is described on the basis of 272 articles in which the SEM was a substantial instrument for research. The first section deals with reproductive cell biology, the various cell types and function in relation to cell surface microstructure. The second section outlines briefly various types of cell and tissue preparation, and advantages and pitfalls. The following sections describe the female reproductive system (including vulva, vaginal and ectocervical squamous epithelium, metaplastic epithelium of the transformation zone, endocervix and cervical mucus, endometrium, IUDs, tube, ovary, and mammary gland), the male reproductive system (male sex organs, spermatozoa) and the conceptus (placenta, embryogenesis). It is indicated where SEM has revealed deeper insights in the structure and function of reproductive cells and tissues and where SEM has a potential for clinical application. The following areas seem promising: the placenta (description of various classes of pathological conditions), the oviduct (description of two types of hydrosalpinges with different prognostic significance), cervical and ascites cytology (SEM's capacity for (early) discrimination of malignant cells) and spermatozoa (prognostic significance of classification with the use of X-ray micro-analysis). In many instances the same results can be obtained by routine LM and TEM. Because SEM does have potentially large diagnostic and prognostic powers further research is essential in order to establish the future role of SEM in the field of human reproduction.

Breast↗

PubMed1983

Shared HLA antigens and reproductive performance among Hutterites.

Shared histocompatibility antigens between spouses may affect reproductive outcome adversely as a result of prenatal selection against compatible fetuses. Evidence from both animal and human studies suggest that histocompatible fetuses may not initiate a maternal immunologic response that prevents rejection of the embryo. Therefore, parents sharing HLA antigens may produce compatible fetuses and consequently experience a greater frequency of early fetal losses and show poorer reproductive outcome than couples not sharing antigens. In the Hutterites, an inbred human isolate that proscribes contraception, we tested the hypothesis that couples sharing HLA antigens have poorer reproductive outcomes than couples who do not. The Hutterites are characterized by high fertility and large family sizes. Couples that share zero (no. = 21), one (no. = 15), and more than one (no. = 10) HLA-A or HLA-B antigens were compared for reproductive performance. Median intervals between births were larger among couples that share more than one antigen in eight of 11 intervals examined. In addition, the median intervals from marriage to first, fifth, and tenth birth were consistently larger among couples that share more than one antigen. Differences among the groups appear to become larger with increasing parity, suggesting that the effect of histocompatibility on reproductive performance becomes more evident in later pregnancies. These differences in reproductive performance between couples that share zero, one, or more than one HLA-A or HLA-B antigens may have significant evolutionary consequences. However, our results demonstrate that sharing HLA antigens does not preclude normal pregnancy and caution should be exercised before concluding that shared HLA antigens are solely responsible for repeated fetal losses.

Birth Intervals↗

PubMedDate not supplied

[The reproductive history of female blood-sucking mosquitoes (Diptera, Culicidae)].

The author classifies current data on the morphology and function of normal and abnormal mosquito ovarioles, obtained with the use of intraovarian oil injections. A combined method for analysis of the female reproductive history is described, that helps elucidate the female reproductive age (the number of ovipositions), the initial fecundity (the number of normal and abnormal ovarioles), the potential fecundity in each gonotrophic cycle (the number of ovarioles with functional germarium), the total potential fecundity (the sum of potential fecundity values in each gonotrophic cycle), the actual fecundity (the number of eggs laid by females) in each gonotrophic cycle, and the total actual fecundity (the number of eggs laid over the female life). The method consists of 3 steps: (1) obtaining of an ovarian preparation, making use of an intraovarian oil injection, that permits a detailed study of every ovariole; (2) inventory of all the ovarioles in the ovary (3 methods are offered for the purpose); (3) quantitative analysis of female reproductive history. The general rule for determination of the reproductive age is as follows: every dilatation, the vestigial ones included, and every granulated site of an egg sac correspond to one reproductive cycle in a normal ovariole. Their sum in an ovariole represents the value of the female reproductive age. The number of the eggs developing in each ovariole corresponds to the number of granulated sites of the egg sac. The potential fecundity may reduce from cycle to cycle, because some ovarioles may become sterile.

Aging↗

PubMed1993

[Influence of somatotropin treatment on the reproduction function in the dairy cow].

Currently somatotropin in being developed for use in several animal species, primarily as a productivity enhancer. The objective of this paper was to review direct and indirect effects of somatotropin supplementation on reproduction particularly in the dairy cow. There is substantial evidence that somatotropin plays an important role in the normal ovarian function. This effect is probably mediated via IGF-I. Existing literature indicates that higher milk yields are antagonistic to reproductive performance and require enhanced nutrition and reproductive management. Similarly, studies indicate that reproductive performance may be impaired in diary cattle supplemented with somatotropin. Effects of somatotropin treatment on reproductive performance may depend on the dose and the stage of lactation. Low doses of somatotropin in early lactation may improve reproductive function.

Animals↗

PubMed1995

Lines of mice selected for reproductive longevity.

Two lines of mice selected for reproductive longevity were compared with one unselected control line to examine longevity and lifetime performance such as number of parturitions during lifetime. Mice were pair mated at about 8 weeks of age and cohabited throughout life. Litter size was reduced to eight at birth in selected line 121 and unselected control line 221, but not in selected line 141. At generation 16, the average number of days from mating to the last parturition was 240.8, 243.0 and 134.6 for lines 121, 141 and 221, respectively. Selected lines 121 and 141 had 80% and 93%, respectively, greater number of parturitions during their lifetimes than the control line. Mean litter size at the early stage of reproduction was similar in the selected and control lines, but persistency of reproduction differed markedly. The average number of young born alive per breeding pair during a lifetime was 77.2, 82.8 and 45.9 for lines 121, 141 and 221, respectively. Data from the short-lived half of the mouse lines showed that mean lifespan was 17% longer in the selected lines 121 and 141 (377.5 and 436.5 days, respectively) than the control line 221 (346.8 days), and phenotypic and genetic correlations between reproductive longevity and lifespan were in the neighbourhood of 0.75 and 0.25, respectively. It was concluded that reproductive longevity was improved through selective breeding and lifespan increased as a correlated response to selection for increased reproductive longevity. The mouse lines derived from this study represent a unique mammalian model for studying various aspects of aging and longevity.

Animals↗

PubMed1997

Reproductive phase dependent effects of dietary L-tryptophan on biochemical constituents of pineal gland in male Indian palm squirrel, Funambulus pennanti.

Tryptophan serves as the substrate for the synthesis of various hydroxy- and methoxyindoles in the pineal gland. In the present study L-tryptophan (L-Trp; 0.5 mg/animal/day) was given in drinking water to male Indian Palm Squirrel for 30 days during reproductive active and pineal inactive phase (April) as well as during reproductive inactive and pineal active phase (December). During reproductive active phase serotonin (5-HT) content of pineal gland increased while accessory sex organ's weight decreased without affecting testes weight. During reproductive inactive phase all the biochemical constituents (protein, cholesterol and serotonin) of pineal gland decreased while testes and accessory sex organ's weight increased. This indicates a reproductive phase dependent effect of L-Trp on the biochemistry of pineal gland including 5-HT synthesis/release which in turn (via melatonin) manipulates reproductive functions of this rodent.

Animals↗

PubMed1998

Assisted reproduction technology, multiple births, and adverse perinatal outcome.

The increase in the rate of multiple pregnancies in Australia in recent years is primarily due to the use of assisted reproduction technology. Compared to singleton births, fetal, neonatal, and perinatal mortality rates are 3-6 times higher in twins and 5-15 times higher in multiple births of a higher order. Cerebral palsy rates among survivors are six times higher in twins and twenty times higher in triplets. The increased risks in multiple pregnancies are not entirely explained by their higher prematurity and low birthweight rates. In Australia, the practice of transferring more than three embryos in any one assisted reproduction technology cycle has declined in recent years and, as a result, the number of multiple pregnancies from assisted reproduction technology has also declined. Nevertheless, assisted reproduction technology pregnancies remain to have poorer than normal outcome with regards to spontaneous abortion, ectopic pregnancy, preterm birth, low birthweight, and perinatal mortality. Infants born after assisted reproduction technology have a higher neonatal morbidity rate, including a greater requirement for assisted ventilation, and a higher long-term neurodevelopmental disability rate. These adverse outcomes following assisted reproduction technology are partly due to the increased risk of multiple pregnancy and partly due to preterm and low birthweight. This fact and the lack of evidence that the transfer of more than two embryos improves pregnancy rates, make it advisable to limit the number of embryos transferred to no more than one or two per cycle.

Australia↗

PubMedDate not supplied

Reproductive life of Bhoksa women.

The paper discusses the reproductive life of 111 ever-married Bhoksa women. The mean age at marriage for women of all ages among Bhoksas, like other tribal populations, is high, unlike the caste populations. The mean ages at first birth of the pooled sample and of the completed fertility cases suggest late and early marriages of the older and younger generations. The maximum number of marriages occur between 15 and 19 years and of first births between 16 and 20 years. Percentage of reproductive wastage is high in both the lower and higher age groups. Young mothers with low birth orders and older mothers with high birth orders display a high frequency of reproductive wastage. Evidently, both birth order and the age of the mother have effects on reproductive wastage. Average number of children ever born (including stillbirth but not abortion or miscarriage) per mother of all ages is the highest among Bhoksas of all the studied ethnic groups of India. The Bhoksa, like caste populations, show a high number of children ever born per mother of completed fertility. Quite a high masculinity in the secondary sex ratio, like other mongoloid population is noticed. The contribution of mortality component to the Total Index of Opportunity for Selection is more than that of the fertility component. Bhoksas conform to the general low range of net reproductive index, which is however greater than unity, suggesting that they are in a growth stage.

Age Factors↗

PubMed2003

Women's perceptions and practices regarding their rights to reproductive health.

ABSTRACT At the outpatient clinic of Ain Shams University Maternity Hospital, perceptions and practices of 1000 women regarding their reproductive health rights (reproductive rights) were evaluated. The majority had positive perceptions about their rights to reproductive health; however, 30% disagreed with prohibitions of discrimination against women, particularly prohibitions of female genital mutilation (FGM). A significant association was found between perceptions of sexual rights and demographic characteristics and between education and practices regarding early detection of cancer. No significant association was found between education and concepts of adolescent health education as a reproductive right. Programmes about women's reproductive rights that emphasize the issue of sexual health through religious education are recommended as one of the best strategies for the eradication of FGM.

Adult↗

PubMed2000

Morphology and histology of the male reproductive system in two species of internally inseminating South American catfishes, Trachelyopterus lucenai and T. galeatus (Teleostei: Auchenipteridae).

As part of an effort to characterize reproductive modifications in internally inseminating catfishes, ovaries and male reproductive systems were examined histologically in two species of auchenipterid catfishes, Trachelyopterus lucenai and T. galeatus, from southeastern Brazil. Internal insemination was documented in both species by the presence of sperm within ovaries. Although there is some variation in gross morphology of the male reproductive systems between the two species, both have four main regions: spermatogenic lobes, sperm storage regions, and secretory and storage regions of the seminal vesicle. In both species, the anterior portion of the reproductive system is spermatogenic and divided into numerous finger-like lobes. Posterior to the spermatogenic area is the storage region of the seminal vesicle, a large median structure with a honeycomb-like appearance. This region is consistently larger in T. lucenai. Attached to the storage region of the seminal vesicle in both species are secretory lobes comprised of tubules lined by secretory cells. These lobes in T. lucenai are small and located on the anterior aspect of the storage region of the seminal vesicle, whereas in T. galeatus the lobes are much larger and located laterally. The sperm storage regions of T. lucenai consist of two large lobes located ventral to the storage region of the seminal vesicle. Highly compact sperm packets (spermatozeugmata) fill the lumina of the ramifying tubules of these regions. Each spermatozeugma consists of elongate nuclei tightly arranged parallel to one another. In T. galeatus two distinct sperm storage regions are present. Just posterior to the spermatogenic lobes a series of small lobes serve as anterior sperm storage regions. Posterior to the secretory lobes of the seminal vesicle is a series of lobes, at the most posterior aspect of the reproductive tract, that serve as posterior sperm storage regions. Both are identical, histologically, to the sperm storage regions of T. lucenai. An absence of compact spermatozeugmata in the T. galeatus specimens may be related to variations in their sexual activity. The descriptions presented here allow for consistent terminology for comparison of regions of the male reproductive system based on presumed function.

Animals↗

PubMed1999

Reproductive skew and indiscriminate infanticide.

In communally breeding animals, there is an evolutionary conflict over the partitioning of reproduction within the group. If dominant group members do not have complete control over subordinate reproduction, this conflict may favour the evolution of infanticidal behaviour (by either subordinates or dominants or both). Elimination of offspring, however, is likely to be constrained by the difficulty of discriminating between an individual's own progeny and those of cobreeders. Here, we develop an evolutionarily stable strategy (ESS) model of reproductive partitioning, which demonstrates that killing of young can be favoured, even if such discrimination is not possible. The model predicts that infanticide will typically be associated with elevated levels of offspring production, and is most likely to prove evolutionarily stable when the coefficient of relatedness between cobreeders is low, and offspring are cheap to produce. The effect of infanticide is to release subordinates from the reproductive restraint they would otherwise be forced to exercise, leading to reduced reproductive skew. When infanticide is possible, addition of numerous young to the joint brood will not lower overall productivity, because progeny in excess of the most productive brood size are eliminated. Subordinates are thus free to contribute more young to the brood than would otherwise be the case. In addition, we show that the possibility of infanticide may influence the pattern of reproduction within a group even if no offspring are actually killed at equilibrium. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗

PubMed1998

Telomerase activity in the female reproductive tract and neoplasms.

OBJECTIVE: To study a possible utility of telomerase determination for cancer diagnosis. METHODS: In a total of 227 tissue samples comprising 114 normal tissues of the reproductive age, 10 fallopian tubes of the postmenopausal age, and 103 neoplastic tissues from female reproductive tracts, telomerase activity was determined. Using densitometrical analysis, telomerase activity was compared between carcinoma tissues and normal counterparts. RESULTS: A total of 97.3% (71/73) of cancer samples comprising ovarian carcinoma, endometrial carcinoma, and epidermoid carcinoma of the cervix and 89.5% (77/86) of the epithelia of the reproductive-aged uterus and fallopian tube showed telomerase activity. The epithelia of the fallopian tube of reproductive age showed significantly higher frequency of positivity (16/18) than the postmenopausal epithelia of the tube (3/10). No difference in telomerase activity was found between endometrial carcinomas and normal proliferative endometria. A significantly higher activity was found in ovarian epithelial carcinoma and epidermoid carcinoma of the cervix than in normal counterparts, although 92% (11/12) of the normal exocervix and 30% (3/10) of the normal ovary showed telomerase activity. CONCLUSIONS: Most epithelia of the female reproductive tract maintain telomerase activity during the reproductive age. Therefore, the detection of malignancies by telomerase determination may be feasible in ovarian carcinoma and epidermoid carcinoma of the cervix, but requires accurate quantification of telomerase activity.

Adult↗

PubMed2000

Stimulatory effects on the reproductive axis in female songbirds by conspecific and heterospecific male song.

Courtship vocalizations of male songbirds can profoundly enhance the reproductive physiology and behavior of conspecific females. However, no study has fully investigated the selectivity of conspecific song effects on reproductive development in birds. We studied the effects of conspecific and heterospecific song on reproductive development in domesticated (canaries) and wild songbirds (song sparrows). As expected, conspecific song enhanced follicular development. Unexpectedly, however, birds exposed to heterospecific song also underwent enhanced follicular development (compared to birds exposed to no song); conspecific and heterospecific songs were equally effective in enhancing ovarian development. In canaries exposed to 18L:6D, conspecific song induced oviposition earlier and at a greater frequency than in heterospecific and no song groups, with the fewest eggs being laid in the no song group. These results indicate that conspecific and heterospecific male song can enhance reproductive activity in female songbirds. Whether or not activation of the reproductive axis in female songbirds by heterospecific song occurs in the wild remains unclear. It is also unclear as to whether the ability of the reproductive axis to respond to heterospecific song performs a specific function, or whether it is simply a consequence of greater selection pressure acting upon behavioral responses to song.

Animals↗

PubMed2001

Posthatch oral estrogen exposure impairs adult reproductive performance of zebra finch in a sex-specific manner.

We determined whether short-term, posthatch oral exposure to estradiol benzoate (EB) or the industrial surfactant octylphenol (OP) could impair the reproductive performance of zebra finches. If so, naturally occurring phytoestrogens and xenoestrogens might influence reproduction in wild populations. Chicks were given oral administration of 10 or 100 nmol EB per gram of body mass (earlier work showed the latter to be the minimum oral dose required to maximally masculinize female song nuclei) or an equimolar amount of OP daily from 5 through 11 days of age. Canola oil was used as a vehicle and control. Reproductive testing was done either in individual pair cages or in communal cages that permitted self-selection of mates, N = 10 pairs per group. Pairs consisted of EB-treated males and females, EB-treated males paired with canola-treated females, vice versa, and canola-treated males and females. Posthatch EB treatment produced sex-specific impairments in reproduction that, in some instances, were additive when both sexes were treated. Egg production was reduced and egg breakage was increased in 100 nmol/g EB-treated male and female pairs. The incidence of missing eggs was increased in 10 nmol/g EB-treated male and female pairs. Candled fertility was reduced in both groups containing 100 nmol/g EB-treated males. The number of hatched chicks was severely reduced in all EB-treated groups. No adverse effects of OP treatment were detected. These significant treatment effects (all P < 0.05) show that posthatch EB treatment profoundly disrupts the reproductive performance of zebra finches, suggesting that exposure to estrogens in the wild could impair the reproductive performance of wild populations.

Age Factors↗

PubMed1998

Evolutionarily Stable Reproductive Strategies in Sexual Organisms: IV. Parent-Offspring Conflict and Selection of Seed Size in Perennial Plants.

The provisioning of offspring in sexually reproducing organisms provides an arena in which genetic conflict of interests between parents and their offspring may be expressed. While most existing models of parent-offspring-conflict consider the case of a parent that rears one offspring a year, this paper is concerned with perennial plants that produce many seeds at one time. Parent-offspring conflict is examined in the context of an integrated analysis of reproductive allocation, sex allocation, and the amount of resources invested in each offspring. I derive the evolutionarily stable strategy (ESS) results for the allocation of resources when the mother plant is in control as well as when the offspring are in control taking into account both density-independent and density-dependent population growth. To the extent that the relationships between gamete output and resource investment are linear for both sex functions, the separate treatment of reproductive effort, sex allocation, and offspring size-number compromise in modern life-history theories is justified, regardless of which side, parents or offspring, wins the conflict. In such cases, the ESS sex allocation is exactly what is found in traditional sex allocation theory, and the ESS reproductive effort maximizes the rate of population growth in density-independent populations, or the amount of resources allocated to reproduction during an average lifespan in density-dependent populations. In contrast to the previous theoretical conclusions based on the analyses of single-offspring cases, the ESS reproductive effort under the offspring's control of allocation to individual offspring is found to be lower than that when mothers are in control. This paradoxical result occurs because a mother producing fewer ovules fares better if she knows that each of her seed offspring will get more resources than the amount she is selected to give. The evolutionarily stable offspring size in both density-independent and density-dependent populations does not depend on mother's reproductive effort and investment-independent mortality, just as traditional models of offspring size-number trade-offs would predict.Copyright 1998 Academic Press Limited

Journal Article↗