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PubMed2005

Are reproductive and somatic senescence coupled in humans? Late, but not early, reproduction correlated with longevity in historical Sami women.

Evolutionary theory of senescence emphasizes the importance of intense selection on early reproduction owing to the declining force of natural selection with age that constrains lifespan. In humans, recent studies have, however, suggested that late-life mortality might be more closely related to late rather than early reproduction, although the role of late reproduction on fitness remains unclear. We examined the association between early and late reproduction with longevity in historical post-reproductive Sami women. We also estimated the strength of natural selection on early and late reproduction using path analysis, and the effect of reproductive timing on offspring survival to adulthood and maternal risk of dying at childbirth. We found that natural selection favoured both earlier start and later cessation of reproduction, and higher total fecundity. Maternal age at childbirth was not related to offspring or maternal survival. Interestingly, females who produced their last offspring at advanced age also lived longest, while age at first reproduction and total fecundity were unrelated to female longevity. Our results thus suggest that reproductive and somatic senescence may have been coupled in these human populations, and that selection could have favoured late reproduction. We discuss alternative hypotheses for the mechanisms which might have promoted the association between late reproduction and longevity.

Aging↗
PubMed1997

Influence of breeding season and reproductive status on male reproductive characteristics in the common mole-rat, Cryptomys hottentotus hottentotus.

The effects of breeding season and reproductive status on male reproduction were investigated in the common mole-rat (Cryptomys hottentotus hottentotus), a co-operatively breeding rodent that exhibits seasonal reproduction and a reproductive division of labour. Testicular anatomical and histological morphometrics, and selected sperm parameters were studied in 50 males from 17 wild caught colonies. Males exhibited no apparent manifestation of season on testicular activity: spermatogenesis and sperm quality (motility and percentage normal morphology) were similar in the reproductively active and inactive periods. This maintenance of reproductive activity during the non-reproductive period is essential in C. h. hottentotus males, as this period coincides with the period of maximal dispersal opportunities. Such reproductive activation in dispersing males may aid intersexual recognition, and assist pair-bond formation or successful assimilation into foreign colonies, thereby facilitating later outbreeding. Consequently, outbreeding opportunities may be important determinants of reproductive activity in male common mole-rats, moderating seasonal effects. Reproductive and non-reproductive males revealed no differences in any of the testicular or sperm parameters studied. The absence of a physiologically well-defined suppression of reproduction in male common mole-rats is more typical of social suppression in male mammals.

Animals↗
PubMedDate not supplied

Reproductive health awareness: an important dimension to be integrated into existing sexual and reproductive health programs.

The ultimate goal of any sexual and reproductive health program is to ensure cost effectiveness, quality and sustainability. Reproductive health awareness is an educational approach which is both relevant and sensitive to many communities' existing sexual and reproductive health needs and concerns. When working with community groups, a participatory approach that includes reproductive health awareness concepts is a simple non-threatening way for programs to quickly expand beyond pure information giving and explore what reproductive health means to people. Although many community sexual and reproductive health programs do not the term reproductive health awareness, they use techniques similar to the reproductive health awareness education approach, when facilitating discussions about sexual or reproductive health. If reproductive health awareness is identified and included as one of the dimensions of future sexual and reproductive health programs, this will hopefully strengthen the program's overall quality and effectiveness.

Awareness↗
PubMed1990

Reproductive toxicity: male and female reproductive systems as targets for chemical injury.

On the basis of current knowledge of reproductive biology and toxicology, it is apparent that chemicals affecting reproduction may elicit their effects at a number of sites in both the male and the female reproductive system. This multiplicity of targets is attributable to the dynamic nature of the reproductive system, in which the hypothalamic-pituitary-gonadal axis is controlled by precise positive and negative feedback mechanisms among its components. Interference by a xenobiotic at any level in either the male or the female reproductive system may ultimately impair hypothalamic or pituitary function. Normal gonadal processes such as spermatogenesis or oogenesis, ejaculation or ovulation, hormone production by Leydig or granulosa cells, and the structure or function of the accessory reproductive structures (e.g., epididymis, fallopian tube) also appear vulnerable to xenobiotics. The reproductive system is a complex one that requires local and circulating hormones for control. This brief review illustrates a system for characterizing the mechanism of action of reproductive toxicants, as well as for defining the sites available for disruption of reproduction. Unfortunately, at present, data addressing the actual vulnerability of reproduction are sorely lacking. However, when experiments have been conducted and combined with epidemiologic data or clinical observation, it has been possible to demonstrate impairment of reproductive processes by xenobiotics. The role of environmental exposure to xenobiotics in the increase in infertility that has been observed remains to be defined.

Environmental Exposure↗
PubMed2005

Trade-off between current reproductive effort and delay to next reproduction in the leatherback sea turtle.

The trade-off between current and future reproduction plays an important role in demographic analyses. This can be revealed by the relationship between the number of years without reproduction and reproductive investment within a reproductive year. However, estimating both the duration between two successive breeding season and reproductive effort is often limited by variable recapture or resighting effort. Moreover, a supplementary difficulty is raised when nonbreeder individuals are not present sampling breeding grounds, and are therefore unobservable. We used capture-recapture (CR) models to investigate intermittent breeding and reproductive effort to test a putative physiological trade-off in a long-lived species with intermittent breeding, the leatherback sea turtle. We used CR data collected on breeding females on Awa:la-Ya:lima:po beach (French Guiana, South America) from 1995 to 2002. By adding specific constraints in multistate (MS) CR models incorporating several nonobservable states, we modelled the breeding cycle in leatherbacks and then estimated the reproductive effort according to the number of years elapsed since the last nesting season. Using this MS CR framework, the mean survival rate was estimated to 0.91 and the average resighting probability to 0.58 (ranged from 0.30 to 0.99). The breeding cycle was found to be limited to 3 years. These results therefore suggested that animals whose observed breeding intervals are greater than 3 years were most likely animals that escaped detection during their previous nesting season(s). CR data collected in 2001 and 2002 allowed us to compare the individual reproductive effort between females that skipped one breeding season and females that skipped two breeding seasons. These inferences led us to conclude that a trade-off between current and future reproduction exists in leatherbacks nesting in French Guiana, likely linked to the resource provisioning required to invest in reproduction.

Animals↗
PubMed2005

Reproductive health needs and the reproductive health behaviour of the youth in Mangaung in the Free State province: a feasibility study.

From the community profiles conducted by nursing students in Mangaung, the following observation was prevalent: an increase in the prevalence of teenage pregnancy together with a high prevalence of HIV infection was demonstrated. The relationship between young people's reproductive behaviour and the prevalence of HIV is well documented. To address this problem, a community -based education programme is required. Developing a successful community-based educational programme that addresses the needs of youth requires that such a programme be based on the needs of such a group. The research question is applicable: How do youth in Mangaung in the Free State province in South Africa perceive their reproductive health needs and their reproductive health behaviour? The aim of this article is to explore and describe the reproductive health needs and the reproductive health behaviour of the youth in Mangaung. A quantitative research design that is descriptive and explorative in nature was conducted. The reproductive health needs and the reproductive health behaviour of the youth were collected by means of a structured questionnaire with open-ended and closed questions. A purposive non - probability sampling method was utilized and (n=250) drawn from the youth. The justification of the sample was further enhanced by collecting data from youth aged 13-25 at three high schools in Mangaung and at the health centre of MUCPP. Qualitative data obtained from open-ended questionnaires was coded and analyzed by using Tech's (1990) content analysis approach. A descriptive statistical analysis was performed on the quantitative data from closed questions. A descriptive analysis of the participant's ages and their perceived reproductive health needs and reproductive health behaviour was done. The mean age of the participants was 18.6, which could be because all the respondents were of school- going age. The results indicated that the youth received insufficient reproductive health information to be able to prevent pregnancy and HIV/AIDS. The special needs of youth were indicated by 92% who requested that the clinic should accommodate both boys and girls and 96% of the respondents requested sessions for discussions facilitated by a professional person. A total of 95% of the youth requested that a special programme of activities be conducted during school holidays. The risk behaviours practised by the youth were: having sex with a stranger, many partners, drinking alcohol, and using drugs and dagga. The researcher recommends that such a programme be supported by different university departments and rolled out to different

Adolescent↗
PubMed2004

Reproductive problems directly attributable to long-term captivity--asymmetric reproductive aging.

Problems attributable to long-term captivity have been identified and are responsible for the difficulties in establishing successful reproduction in captive populations of wildlife, specifically, elephants and rhinoceroses. Historically, non-reproductive periods of 10-15 years in nulliparous female rhinoceroses and elephants have not been considered problematic. New evidence suggests that prolonged exposure to endogenous sex steroids and that long stretches of non-reproductive periods induce asymmetric reproductive aging in captive animals. The consequences are reduced fertility, shortened reproductive life-span and, eventually, irreversible acyclicity. Although age-related reproductive lesions have also been documented in male rhinoceroses, they continue to maintain a longer reproductive life-span than females. Since human and domestic animal models have already indicated that early pregnancy provides natural protective mechanism against asymmetric reproductive aging processes and premature senescence, it is imperative that appropriate counter measures such as assisted reproductive technologies (ART) be utilized to ensure early pregnancy in captive animals for their preservation and to ensure increased genetic diversity of the captive populations.

Aging↗
PubMed2006

Endometriosis and assisted reproduction: the role for reproductive surgery?

PURPOSE OF REVIEW: The aim of this review paper is to discuss the relationship between endometriosis and assisted reproductive technology. More specifically, the following clinically relevant issues will be discussed. (1) Does the presence of endometriosis affect the outcome of assisted reproductive technology? (2) Does surgical treatment for endometriosis prior to or after assisted reproductive technology treatment affect the outcome of assisted reproductive technology? (3) Is assisted reproductive technology a risk factor for the recurrence of endometriosis after medical or surgical therapy? RECENT FINDINGS: The review is based on recently published review papers/meta-analyses or international guidelines as published by the European Society of Human Reproduction or the American Society of Reproductive Medicine, updated with a selective review of recent papers searching PubMed with the key words 'Endometriosis', 'Assisted Reproduction', 'IVF', 'IUI' and 'Reproductive Surgery'. SUMMARY: At the end of this review, a practical proposal for the clinical management of women with endometriosis-associated subfertility is proposed, based on our own experience.

Endometriosis↗
PubMed2003

Temporal localization of porcine reproductive and respiratory syndrome virus in reproductive tissues of experimentally infected boars.

Porcine reproductive and respiratory syndrome virus (PRRSV) has been reported to be shed in the semen of infected boars. To determine whether the reproductive tissues could be a persistent source of virus and the possible origin of PRRSV found in semen of infected boars, 20 PRRSV-seronegative boars were intranasally inoculated with 5 x 10(6) median tissue culture infective doses (TCID50) of PRRSV and necropsied at different times post-inoculation (p.i.) from Day 2 to Day 37 p.i. Blood samples were collected before experimental inoculation, at necropsy and at different times p.i. At necropsy, epididymal semen and reproductive tissues were collected and the presence of the virus determined by virus isolation. The infection of the boars was demonstrated by the isolation of the virus from the sera of all inoculated boars and by seroconversion. PRRSV was detected in serum samples from Day 2 to Day 23 p.i., although the viremic period was largely dependent on the individual response to infection. Viral replication was proven within different reproductive tissues from Day 2 to Day 23 p.i., being most consistently found in the epididymus. In addition, PRRSV was isolated in semen from Day 4 to Day 10 p.i. The correlation of a diminished viremia and the inability to isolate PRRSV from semen or reproductive tissues may be due to one of two possibilities. First, viremia is responsible for most of the virus isolated from reproductive tissues due to the movement of PRRSV-infected cells out of the blood and into the tissues. Second, viremia may initially seed the reproductive tissues with PRRSV, and then the virus is produced into the reproductive tract and shed into semen at low levels.

Animals↗
PubMed2003

Physiological costs of reproduction in the Sydney rock oyster Saccostrea glomerata. How expensive is reproduction?

In this study, triploid Sydney rock oysters Saccostrea glomerata, which do not reproduce and have only limited gonadal development, were used to calculate the cost of producing and maintaining somatic tissues. The consumption of oxygen was measured and converted to units of energy expended. The consumption of oxygen of diploid oysters, in different stages of the reproductive cycle, was also measured. Knowing the costs of producing and maintaining somatic tissues (obtained from the triploid oysters), it was possible to calculate the energy demand of somatic and reproductive tissues of diploid oysters. The focus of this study was to test whether this method would work, to investigate if this method would give results in accordance with modern life-history theory and to test hypotheses about costs of reproduction in oysters. It was found that in diploid oysters, 27% of the consumed oxygen was needed for reproductive processes. It was also found that the costs of production and maintenance of reproductive tissues were on average 84% of those of somatic tissues. Costs for the production and maintenance of somatic tissues decreased over time. Costs for reproduction also decreased, but were dependent on the stage of gonadal development. If the relative mass of gametes in the gonads was large, the costs were relatively small; if the mass was relatively small, the costs were large. Differences between traits of males and females were never significant, suggesting that reproductive effort and costs were similar in males and females. It was estimated that if diploid oysters did not reproduce, they could gain 64% more somatic ash-free dry mass. Thus, in terms of growth, reproduction is an expensive activity.

Animals↗
PubMed1994

Infectious diseases, reproductive effort and the cost of reproduction in birds.

Reproductive effort can have profound effects on subsequent performance. Field experiments on the collared flycatcher (Ficedula albicollis) have demonstrated a number of trade-offs between life-history traits at different ages. The mechanism by which reproductive effort is mediated into future reproductive performance remains obscure. Anti-parasite adaptation such as cell-mediated immunity may probably also be costly. Hence the possibility exists of a trade-off between reproductive effort and the ability to resist parasitic infection. Serological tests on unmanipulated collared flycatchers show that pre-breeding nutritional status correlates positively with reproductive success and negatively with susceptibility to parasitism (viruses, bacteria and protozoan parasites). Both immune response and several indicators of infectious disease correlate negatively with reproductive success. Similar relations are found between secondary sexual characters and infection parameters. For brood-size-manipulated birds there was a significant interaction between experimentally increased reproductive effort and parasitic infection rate with regard to both current and future fecundity. It seems possible that the interaction between parasitic infection, nutrition and reproductive effort can be an important mechanism in the ultimate shaping of life-history variation in avian populations.

Animals↗
PubMedDate not supplied

Relationship of reproductive cycle-associated and non-reproductive cycle-associated psychological problems in women.

OBJECTIVE: To determine the frequency of past psychological problems associated with the reproductive cycle in women seeking routine gynecological care. METHODS: Three hundred and sixty-eight women of menopausal age seen at a university medical center gynecology clinic were mailed a questionnaire requesting information about past mood or anxiety problems associated with specific reproductive cycle or hormone use times, such as the premenstruum, pregnancy, postpartum, perimenopause, following total hysterectomy with bilateral salpingo-oophorectomy, and during oral contraceptive or hormone replacement treatment. Chi-square analysis was done between groups categorized as with and without reproductively associated psychological problems (RAPP) and with or without non-reproductively related psychological problems (non-RAPP). Relative risk of women with RAPP having non-RAPP also was calculated. Results-One hundred thirteen women returned the questionnaire. Fifty percent of these women reported a past history of reproductive cycle-associated psychological problems (RAPP). Of these, 37% also reported psychological problems at times in their lives not associated with particular reproductive cycle (non-RAPP) times. However, of the 50% of women who reported no history of RAPP, only 14% reported non-RAPP. This was a significant difference between the groups (p = .0064). There was also a 2.7 times greater risk of women with RAPP also having non-RAPP (RR 2.7). CONCLUSIONS: Women with reproductively associated psychological problems have a greater risk of also having psychological problems at non-reproductively associated times.

Adult↗
PubMed1996

A somatic reproductive organ enhancer complex activates expression in both the developing and the mature Drosophila reproductive tract.

The Glucose dehydrogenase (Gld) gene is highly expressed in the mature Drosophila reproductive tract. Unlike several other Drosophila genes which function in reproductive physiological processes, Gld is also expressed extensively in the developing reproductive tract during metamorphosis. Proximal promoter elements drive Gld expression in a variety of tissues throughout development, but not in the reproductive tract. Herein, we have identified a somatic reproductive organ enhancer complex (SREC) containing multiple redundant enhancer modules in Gld intron I (+639 to +3906 nt). The SREC, in combination with the Gld promoter, activates beta galactosidase reporter gene expression in both the developing and the mature reproductive tract. The SREC activates a heterologous hsp70 promoter in the ejaculatory duct, but not in other reproductive tract tissues, suggesting that the SREC acts synergistically with Gld promoter proximal elements. Through deletion analysis we have delimited a 361-nt region of the SREC that is involved in ejaculatory duct/oviduct-specific expression. The ejaculatory duct/oviduct enhancer retains the ability to activate expression in both the developing and the mature reproductive tract, suggesting that the same basic enhancer elements activate Gld expression during metamorphosis and in adults. A model of the evolution of Gld expression in the ejaculatory duct and oviduct is presented.

Animals↗
PubMed1995

Cell proliferation kinetics of normal and tumour tissue in vitro: quiescent reproductive cells and the cycling reproductive fraction.

Current methods for measuring the cell kinetics of human tumours are made and interpreted within the context of a simplistic two compartment model for cell proliferation, consisting of cells that are cycling and those that are not. It is now recognized that the non-cycling compartment of many tumours is heterogeneous, composed of non-reproductive end-stage cells and reproductive cells that are dormant/quiescent. We have developed an in vitro analysis that distinguishes for the first time quiescent reproductive cells from non-reproductive end-stage cells and have integrated this analysis with monolayer clonogenic and suicide assays to simultaneously quantitate the duration of the cell cycle and reproductive cells that are: cycling, quiescent, clonogenic, and non-reproductive end-stage cells. We have defined a new parameter, the Cycling Reproductive Fraction (CRF), which is the cycling cell population referenced specifically to the reproductive cell population. Measurements of CRF from 72 tumour biopsies and from 5 normal foreskins showed that CRF approached 100% in some tumours; however, CRF showed near normal values (< 1%) in others suggesting that cell cycle control may be maintained in some tumours. Because of CRF's improved specificity, we believe that CRF may enhance classification, prognostication, and the optimization and prediction of response to chemotherapy.

Breast Neoplasms↗