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Migration and stability.

"In this endeavor to incorporate net migration in a model of population growth, we have found that when net maternity rates are held constant, birth trajectories can be traced in several examples. We have basically experimented with (a) unchanging age-specific net migration rates and also with (b) constant number of net migrants with unchanging age composition. In most cases, the birth trajectory approaches an exponential pattern of growth with two interesting exceptions. When the intrinsic rate of growth is negative, the population approaches stationarity in the second example. Also a linear trend is found in the same example, when the net reproduction rate is equal to one." (SUMMARY IN FRE AND ITA)

Age Distribution↗

Sperm transport in the female reproductive tract of the brushtail possum, Trichosurus vulpecula, following superovulation and artificial insemination.

This study investigated sperm transport following superovulation and artificial insemination (AI) in the common brushtail possum, Trichosurus vulpecula. Females were superovulated by treatment with 15 IU pregnant mare serum gonadotrophin (PMSG) then 4 mg luteinizing hormone (LH) 78 h later. Inseminations were performed 27 h after LH (4 million motile spermatozoa/uterus). At 1.5, 3, 6, 9 and 12 h after AI (n=5 per group), females were euthanised and reproductive tracts removed for examination and flushed for sperm. No ovulations had occurred by 1.5 h, but 20% of animals had ovulated by 3 or 6 h, and 80% by 9 or 12 h. The mean numbers of spermatozoa recovered ranged from 249 to 275x10(3) in the uterus; 16-51x10(3) in the isthmus; 8-11x10(3) in the middle segment; and 6-16x10(3) in the ampulla at 1.5, 3 and 6 h after AI. Sperm numbers in all regions decreased at later times (P<0.05) except the isthmus, where 100x10(3) sperm were recovered by 12 h. Highly motile thumbtack sperm (a putative indicator of capacitation in marsupials), were recovered from the isthmus (20%), middle segment (50%) and ampulla (90%) at all sampling times, but not from the uterus. The epithelium of the oviduct segments contained mucus-secreting and ciliated cells and peak secretory activity was observed in the ampulla at 6 h. At 3, 6 and 12 h, many spermatozoa were found in epithelial folds within the isthmus. The present study has provided basic information on sperm transport and storage events within the female reproductive tract of T. vulpecula following superovulation and AI. It is concluded that this model may be useful to better understand pre-fertilization sperm maturation events in the possum, which could facilitate the development of IVF technology.

Animals↗

The initial flare-up induced by gonadotropin releasing hormone agonist may serve as a predictor of ovarian response in the current IVF-ET treatment cycle in normogonadotropic women aged 40-48 years.

OBJECTIVE: Our purpose was to assess the potential role of the baseline hormone profile in combination with the initial pattern of response to gonadotropin releasing hormone (GnRH) analogue in predicting ovarian function and hence reproductive outcome in normogonadotropic patients aged 40 years or older undergoing IVF treatment. PATIENTS AND METHODS: A retrospective analysis of 394 controlled ovarian hyperstimulation (COH) cycles that reached the stage of oocyte retrieval was conducted. The study included 163 normogonadotropic (serum FSH < or = 15 IUIL) patients aged between 40 and 48 years who had regular menstrual cycles. Superovulation was achieved using menotropins in combination with GnRH analog (short protocol, beginning on menstrual day 2). The ovarian response was monitored on the third cycle day, the day following the first GnRH analogue administration. RESULTS: Cycle distribution by patient age was 175 (44.4%), 122 (30.9%), and 97 (24.7%), while the patient distribution was 85 (52.2%), 48 (29.5%), and 30 (18.3%) for age groups 40-41, 42-43, and 44-48 years, respectively. The mean total dose of menotropins needed for optimal COH was 1787 IU (range, 600-6000 IU). This dose increased with age, while the yield of oocytes and embryos declined (P < 0.05; ANOVA). A positive correlation was demonstrated between the E2 level on day 3 (GnRH analogue flare effect) and the outcome of the treatment cycle (number of oocytes and embryos). Using multiple stepwise regression analysis, it was demonstrated that the initial (day 3) serum E2 levels, combined with baseline FSH levels, patients's age and body mass index enabled early prediction of the ovarian response in the current IVF-ET treatment cycle (oocytes = 8.2 - 0.18 x Age + 0.17 x BMI - 0.12 x FSH + 0.0042 x E2). CONCLUSIONS: Multiple-parameter analysis demonstrated that the use of the initial E2 response to GnRH analogue stimulation combined with basic clinical data may assist in the prediction of ovarian function and hence the reproductive outcome in normogonadotropic IVF patients aged 40 years or older. This may serve as a clinical tool for improving patient selection and treatment outcome in IVF-ET.

Adult↗

[Toxoplasmosis in Dakar. Seroepidemiologic sampling of 353 women of reproductive age].

Thanks to a serological survey carried out in Dakar from January to November 1993 among 353 procreative women, immune cover regarding toxoplasmosis was assessed using ELISA methodology: 40.2% of the surveyed population had antibodies of toxoplasmosis. No evidence of age, pregnancy, number of previous pregnancies was noted in antitoxoplasmosis antibodies prevalence. The seroconversion risk seems to be low even when it has existed during pregnancy. Contamination occurred during childhood. Some sanitary education should be provided to the procreative population in order to achieve a better compliance with basic hygiene regulations during pregnancy.

Adolescent↗

Genomics in obstetrics and gynaecology.

With the Human Genome Project complete, and microarray technology progressing rapidly, the study of whole genomes has become a reality. The emerging field of genomics is full of promise, has become a cornerstone of commercial drug development, and looks certain to make a major contribution to clinical practice in the future. There is an increasing number of genomic studies concerned with obstetric and gynaecological conditions. Despite this, clinicians in their busy practices often lack a basic understanding of genomics and the tools involved in generating genome-based information. In the present review, we aim to provide the clinician with a basic overview of genomics--what it is, what tools it uses, and how it may benefit our patients. The existing published reports on genomic studies in the reproductive field is reviewed.

DNA Fingerprinting↗

Reproductive performance of sows supplemented with dietary L-carnitine over three reproductive cycles.

The effect of L-carnitine supplementation during pregnancy and lactation on the reproductive performance of sows was studied in two separate trials over three reproductive cycles. Both trials were identical in design and conduct but were performed with different animals. The trials comprised of a total of 127 sows (trial 1) and 100 sows (trial 2) which were divided into control and treatment groups. All animals were fed individually and received basic feed mixtures with low native carnitine concentrations. The rations of the sows in the treated group were supplemented with 125 mg L-carnitine per head and day during pregnancy and 250 mg L-carnitine per head and day during lactation. The animals of the control group received identical feed mixtures in identical amounts, but without the L-carnitine supplement. In the first trial, 212 litters were produced and evaluated for number and body weight of the animals, in the second trial, 173 litters were produced. L-carnitine supplementation significantly increased body weight gains of the sows between day 1 and day 85 of weaning. The number of born piglets, stillborn piglets and piglets fit for rearing was not influenced by dietary L-carnitine supplementation. However, L-carnitine supplementation significantly increased the weights of piglets and litters at birth, weight gains of litters during suckling and weights of litters at weaning. These effects of L-carnitine were seen in both trials; they were independent of the age of the sows and remained over three reproductive cycles in which the sows where continuously treated with L-carnitine. Overall, the study shows that dietary supplementation with L-carnitine during pregnancy and lactation improves the reproductive performance of sows over several reproductive cycles, independent of the age of the sows.

Animals↗

Controlling emerging infectious diseases like SARS.

To control emerging infectious diseases like SARS, it is necessary to resort to basic control measures that limit exposures to infectious individuals. These measures include isolating cases at diagnosis, quarantining household members and tracing contacts of diagnosed cases, providing the community with advice on how to reduce exposures, and closing schools. To justify such intervention it is important to understand how well each of these measures helps to limit transmission. In this paper, we determine the effect of a number of different interventions on the effective reproduction number and estimate requirements to achieve elimination of the infectious disease. We find that the strategy of tracing and quarantining contacts of diagnosed cases can be very successful in reducing transmission.

Australia↗

[Influence of neurological diseases on partnership and sexuality. Particularly in view of multiple sclerosis and Parkinson's disease].

A great number of neurological diseases exert a direct impact on sexuality, due to lesions in the central and peripheral nervous system and due to different neurological symptoms and their treatment (for example medication). The psychosocial basic needs for acceptance, intimacy, and security, which can be best fulfilled by sexual communication, attain essential importance in the situation of disease-induced helplessness. This implies that not only the experience of sexual pleasure and the functioning of reproduction can be influenced, but the partnership, too. A holistic treatment approach always requires the consideration of partnership aspects.

Female↗

Subfertility and the risk of testicular germ cell tumors (United States).

OBJECTIVES: Previous studies have reported an association between subfertility and the risk of testicular germ cell tumors. We examined fertility, measured by number of children fathered and prior diagnosis of infertility, as a risk factor for testicular cancer, while accounting for the influence of occult cancer and cryptorchidism. METHODS: Tumor registry data were used to identify 329 cases of testicular cancer in white men aged 20 to 69 years, diagnosed in western Washington State from 1977 to 1983; 672 cancer-free controls were identified by random-digit dialing. Telephone interviews ascertained reproductive histories and basic demographic information. Logistic regression was used to estimate the relative risk of testicular cancer associated with fertility. RESULTS: Testicular cancer risk was decreased among men who had previously fathered a child (age-adjusted odds ratio (OR) 0.76, 95% confidence interval (CI): 0.54-1.06). Inverse associations were seen for seminomas and non-seminomas, and only slight attenuations in the ORs were observed when men with a history of cryptorchidism were excluded. Prior diagnosis of infertility was associated with an increased risk of testicular cancer (OR 2.40, 95% CI: 1.00-5.77). CONCLUSIONS: These results are consistent with an increased risk of testicular cancer among men with reduced fertility that goes beyond the effects of cryptorchidism.

Adult↗

Composite model of time-varying appearance and disappearance of neurohormone pulse signals in blood.

Blood-borne neurohormonal signals reflect the intermittent burst-like release of peptides and steroids from neurons, glands and target tissues. Hormones control basic physiological processes, such as growth, metabolism, reproduction and stress-related adaptations. Secreted molecules undergo combined diffusion, advection and irreversible elimination from the circulation. Quantification of these interdependent processes by a structurally relevant model embodying discrete event times, continuous rates of secretion and elimination, and stochastic variations poses a formidable challenge. In an experimental setting, one observes only the hormone concentrations, which comprise a time-varying composite of secretion and elimination. The number, shape and location of underlying bursts (pulses) and attendant secretion and kinetic parameters are unobserved. The ability to estimate the properties of these processes from the observed data is fundamental to an understanding of regulated hormonal dynamics. The present formulation allows objective simultaneous appraisal of discrete (pulse times) and continuous (secretion/elimination) properties of neuroglandular activity in the presence of random variability. A probability distribution is constructed for the structural parameters (secretion/elimination, pulsing), and an algorithm is developed by which one can, based upon observed hormone concentration data, make probabilistic statements about the underlying structure: pulse frequency per day, total basal (constitutive) and pulsatile secretion per day, and half-lives of elimination. The algorithm consists of the following steps: first, explicit construction of a family of sequentially decreasing putative pulse-time sets for a given neurohormone concentration time series; and then, recursive iteration between the following two: (a) for a given pulse-time set, generate a sample from the probability distribution of unknown underlying hormone secretion and elimination rates; and (b) determine whether or not a probability-based transition from one pulse-time set to another is merited (i.e., add/remove a pulse-time or stay the same). We apply this procedure illustratively to joint estimation of pulse times, secretion rates and elimination kinetics of selected pituitary hormones (ACTH, LH and GH).

Activity Cycles↗

Importance of assisted reproductive technologies in the conservation of wild, rare or indigenous ungulates: review article.

Biodiversity is increasingly threatened by intensive agriculture, environmental pollution, extinction of natural habitats and several other factors. Several mammalian species including ungulates have disappeared or are threatened by extinction. However, ungulates play an important role both in the ecosystem and in the economy. In general, species or breeds are considered endangered if their population does not exceed 1,000 individuals. In these cases conservation programmes should be initiated in order to maintain or even increase their number. This review deals with the possibilities and limitations of assisted reproductive technologies (ART) in the conservation of ecologically valuable wild, rare and indigenous ungulates. The methods discussed here are artificial insemination, cryopreservation of semen and embryos, embryo recovery and transfer, in vitro production of embryos, as well as micromanipulation techniques including sperm injection, assisted hatching and cloning. Some of these procedures are already being exploited in the breeding of farm ungulates, but more basic information about the reproductive patterns of wild, rare and indigenous animal species is needed before the routine use of ARTs.

Animals↗

Reproductive and developmental toxicity screening test of basic rubber accelerator, 1,3-di-o-tolylguanidine, in rats.

Twelve male and female rats per group were exposed to the rubber accelerator 1,3-di-o-tolylguanidine (DTG) by gavage at 0, 8, 20 or 50 mg/kg bw/day. Males were dosed for a total of 49 days beginning 14 days before mating. Females were dosed for a total of 40-49 days beginning 14 days before mating to day 3 of lactation throughout the mating and gestation period. At 50 mg/kg bw/day, deaths were observed in two males and three females. Lowered body weight gain and food consumption were noted in males at 50 mg/kg bw/day and females at 20 and 50 mg/kg bw/day. Mydriasis, decreased locomotor activity, bradypnea, prone position, tremor and/or salivation were observed in males and females at 20 and 50 mg/kg bw/day. No effects of DTG were found on the estrous cyclicity, precoital interval, copulation, fertility and gestational indices, numbers of corpora lutea and implantations, or gestation length. A significant decrease in the number, body weight and viability of offspring and increase in the incidence of fetuses with external malformations were found at 50 mg/kg bw/day. Oligodactyly, anal atresia and tail anomalies were observed. These data suggest that DTG may be teratogenic. The NOAELs of DTG for general and developmental toxicity in rats are 8 and 20 mg/kg bw/day, respectively.

Abnormalities, Drug-Induced↗

[Variations in reproductive capacity, gonotrophic cycle and longevity of Anopheles sinensis infected by Brugia malayi larvae].

Under the experimental conditions of 26 +/- 10 degrees C, relative humidity 70-80%, 100 +/- 20 Lux and photoperiod 16 hours/day and using a membrane feeding method, the development of filarial larvae and the variations in reproductive capacity, gonotrophic cycle and longevity of An. sinensis infected with microfilariae of Brugia malayi were observed. The infection rate and infection intensity of filarial larvae in An. sinensis increased with the microfilarial density in the blood meal from 50 to 150 mf/20 microliters. The mature rate and IEI decreased when the density rose to 200 mg/20 microliters. The concentration ratio of mf in blood by An. sinensis was 1.2-1.4. In the 3rd gonotrophic cycle, the feeding ratio of infected mosquitoes became lower when the mf density rose to 150 mf/20 microliters, but the infection of filarial did not affect the number of oviposition, the regularity of egg-production activity and the hatching rate of eggs, while the quantity of egg-production increased when the mf density was 150 mf/20 microliters. The egg-production rate, and gonotrophic cycle were not basically influenced by filarial larvae infection. The multifeeding ratio was 16.7-48.4% in An. sinensis. The longevity of An. sinensis was extended by infection with mf density of 100 mf/20 microliters and shortened in infection with mf density of 200 mf/20 microliters. The authors conclude that "Brugia malayi-Anopheles sinensis" is a highly adapted "pathogen-vector" system.

Animals↗

The Nhlh2 transcription factor is required for female sexual behavior and reproductive longevity.

Nhlh2 is a member of the basic helix-loop-helix (bHLH) transcription factor family and is expressed in developing and adult neuroendocrine tissues such as the pituitary and hypothalamus. Targeted deletion of Nhlh2 (N2KO) in mice results in hypogonadism and obesity. While gonadally intact male N2KO mice are infertile and lack male sexual behavior, female N2KO mice can become pregnant and carry litters to full term. Unlike normal females in which fertility averages 8-12 months with approximately one pregnancy per month, N2KO females have a shorter reproductive span with most females supporting only three to four pregnancies in a 9-month period. In addition, N2KO females exhibit abnormal estrous cycles characterized by a truncated estrus and a prolonged proestrus. We have found that while young female N2KO mice ovulate the same number of oocytes as normal females in response to exogenous hormones, the number of oocytes released by aged N2KO females is reduced over 50%. Interestingly, oocytes from N2KO females are equally competent for in vitro fertilization assays when compared to oocytes from similarly aged normal and heterozygous mice. We have further demonstrated that both young and old N2KO females show at least a 50% reduction in hormone-stimulated sexual behavior as measured by their lordosis quotient. This suggests that N2KO females show a lifelong behavioral hyporesponsiveness to exogenous steroid hormones accompanied by a reduction in reproductive longevity via reduced ovulation with aging. Potential gene regulatory mechanisms that involve the action of the Nhlh2 transcription factor on female fertility and sexual behavior are discussed.

Age Factors↗

Limb development in a "nonmodel" vertebrate, the direct-developing frog Eleutherodactylus coqui.

Mechanisms that mediate limb development are regarded as highly conserved among vertebrates, especially tetrapods. Yet, this assumption is based on the study of relatively few species, and virtually none of those that display any of a large number of specialized life-history or reproductive modes, which might be expected to affect developmental pattern or process. Direct development is an alternative life history found in many anuran amphibians. Many adult features that form after hatching in metamorphic frogs, such as limbs, appear during embryogenesis in direct-developing species. Limb development in the direct-developing frog Eleutherodactylus coqui presents a mosaic of apparently conserved and novel features. The former include the basic sequence and pattern of limb chondrogenesis, which are typical of anurans generally and appear largely unaffected by the gross shift in developmental timing; expression of Distal-less protein (Dlx) in the distal ectoderm; expression of the gene Sonic hedgehog (Shh) in the zone of polarizing activity (ZPA); and the ability of the ZPA to induce supernumerary digits when transplanted to the anterior region of an early host limb bud. Novel features include the absence of a morphologically distinct apical ectodermal ridge, the ability of the limb to continue distal outgrowth and differentiation following removal of the distal ectoderm, and earlier cessation of the inductive ability of the ZPA. Attempts to represent tetrapod limb development as a developmental "module" must allow for this kind of evolutionary variation among species.

Animals↗

International training programs in reproductive sciences for conservation of Latin American felids.

Survival of the ten non-domestic felid species endemic to Latin America is imperiled by habitat loss, poaching and poor captive management. Over the past 10 years, conservation of these felids has been the primary focus of a reproductive research and training program conducted in Brazil, Mexico, and the USA. The objectives of this program were to: (1) provide intensive training in reproductive sciences to Latin American scientists, (2) conduct collaborative studies investigating basic and applied reproduction in endangered felids, and (3) establish a highly-trained scientific cohort to conduct independent conservation-based research. Four formal training courses, consisting of didactic lectures and hands-on instruction in research techniques, including semen collection, sperm cryopreservation and laparoscopic artificial insemination (AI), were taught in Brazil and Mexico between 1995 and 1998. Several of these scientists received further training in conducting fecal hormone analysis in the USA, and a number of research studies, many in collaboration with American scientists, were initiated in Latin American felids. Research findings have characterized basal reproductive traits in several felid species, including ocelots, margay, tigrinas and jaguars, and established that Latin American felids exhibit only minimal seasonal variation in most reproductive traits. Other studies have explored the impact of acute and chronic stressors on adrenocortical activity and demonstrated the importance of environmental enrichment in captivity, especially in small felids. Additional research has examined ovarian and immunological responsiveness of Latin American felids to exogenous gonadotropins and assessed the impact of nutrition on sperm production and oocyte quality. Applied reproductive studies have investigated sperm cryopreservation in both captive and wild felid populations and demonstrated the production of viable offspring in ocelots and tigrinas following laparoscopic AI. Ongoing studies are investigating the potential of in vitro fertilization (IVF), embryo cryopreservation and embryo transfer for genetic management of ocelots and tigrinas. To date, over 75 Brazilian ocelot and 50 tigrina IVF embryos have been cryopreserved and two pregnancies have been established in ocelots following transfer of frozen-thawed embryos. Findings from these studies are helping to improve husbandry, population management, and breeding of Latin American felids in captivity. Continued advances in assisted reproduction eventually may provide an alternative route for exchanging genetic material among Latin American felid populations. Most importantly, this collaborative program has been essential for building scientific capacity, within Brazil and Mexico, in establishing a core group of highly-trained reproductive biologists that will continue applying their new knowledge and skills to the conservation of Latin American felids.

Animals↗

[Progress and change in geriatric gynecological surgery (author's transl)].

Two periods of geriatric gynecological surgery (1947-1959 and 1960-1972) at the University Women's Hospital in Hamburg-Eppendorf were compared in regard to the age of the patient, surgical indications, surgical procedure, anesthetic technique, preoperative and postoperative morbidity, length of hospitalization and mortality rate. During a period of 26 years, 1514 women over the age of 60 were treated surgically. During the first period, 489 women were treated, and in the second period, 1,025. This 109.6% increase has been confirmed statistically. The increase in geriatric surgical cases stems basically from the increase in the number of surgical patients over the age of 70. The increase in breast carcinoma during the second period (from 43 to 348 operations) is most conspicuous. This is an increase of 809.3%. On the basis of this disproportionately large increase in breast surgery, more women were treated surgically in the University Women's Hospital in Hamburg-Eppendorf for breast carcinoma during the second period, than for carcinoma of the reproductive organs. Vulva carcinoma and craurosis vulvae were also more frequently considered to be an indication for surgical treatment. The total number of women who were surgically treated for prolapsed uterus and vagina remained more or less constant. In the analyzing the surgical records, it should be emphasized that, in the second observation period, two-thirds of these cases were treated by performing a vaginal hysterectomy with anterior and posterior vaginoplasty. For older patients, palliative surgical measures for prolapsed uterus and vagina were abandoned in favor of more definitive methods. The postoperative morbidity and mortality rate remained more or less constant for both periods. The postoperative period of hospitalization was slightly longer while the preoperative period was slightly shorter. The statistically confirmed increase in geriatric surgery during the last 13 years at the University Women's Hospital in Hamburg-Eppendorf clearly shows how important geriatric surgery has become. The immediate consequences are an increased workload for physicians, nursing staff and physical therapists.

Age Factors↗

Contact tracing and disease control.

Contact tracing, followed by treatment or isolation, is a key control measure in the battle against infectious diseases. It is an extreme form of locally targeted control, and as such has the potential to be highly efficient when dealing with low numbers of cases. For this reason it is frequently used to combat sexually transmitted diseases and new invading pathogens. Accurate modelling of contact tracing requires explicit information about the disease-transmission pathways from each individual, and hence the network of contacts. Here, pairwise-approximation methods and full stochastic simulations are used to investigate the utility of contact tracing. A simple relationship is found between the efficiency of contact tracing necessary for eradication and the basic reproductive ratio of the disease. This holds for a wide variety of realistic situations including heterogeneous networks containing core-groups or super-spreaders, and asymptomatic individuals. Clustering (transitivity) within the transmission network is found to destroy the relationship, requiring lower efficiency than predicted.

Communicable Disease Control↗