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PubMedDate not supplied

[Importance of microbiologic examination of vaginal secretions in the reproductive period].

Vaginal infections, during reproductive period are frequent and although not life treating, they can affect their normal functions. They can also affect women's fertility as well as the course of pregnancy. The outcome of pregnancy can be endangered due to the possibility of infection of newborn while passing trough birth canal of the infected mother. As statistically shown, bacterial vaginosis is considerably more often found with the patients having precancerous changes on cervix, or diagnosed cancer of cervix, comparing with women with healthy cervix. It can also cause the appearance of postoperative pelvic cellulitis after hysterectomy. On the other side, the presence of S. agalactiae in vaginal secretion may cause very serious and lethal infections of the newborn such as meningitis, pneumonia and sepsis. As for protozoa T. vaginalis it has been shown that it could cause reduced fertility ability and that during pregnancy it could damage fetal membranes and bring to its premature rupture and premature birth. There is also increased risk of cervix cancer. During reproductive period of women especially if risk factors are existing such as hormone therapy, diabetes mellitus type 1 and applications of wide range antibiotics, vaginal fungal infections caused by Candida can frequently appear. These infection apart from the discomfort like itch and affluent secretion they can also mean diagnostic and therapeutical problem. Regular microbiological test of women are highly recommended during reproductive period as standard for bacterial vaginosis, fungal and trichomonas infections. If those results appear negative, further microbiological tests are necessary. Such tests which are more elaborate, more timely and more expensive are referring to tests on chlamydia, microplasma and some viruses that can also be the cause of vaginal secretion disbalance in women during reproductive period.

Adult↗
PubMed2002

Interval between preovulatory surges of luteinizing hormone increases late in the reproductive period in turkey hens.

In turkey hens, the egg production rate is relatively high early during a reproductive period, but declines as the period progresses. Among lines with different egg production potential, the interval between preovulatory surges of LH is the primary determinant of the egg production rate. The main objective of this study was to determine whether the decline in egg production rate late during an egg production period is also associated with a difference in the interval between LH preovulatory surges. A group of photosensitive turkey hens (Early) were photostimulated with continuous light (24L:0D) at 40 wk of age to induce egg laying, and serial blood samples were collected after about 3 wk of egg production. A second group of hens (Late) were housed in floor pens and photostimulated with 14L:10D at 40 wk of age for a normal 36-wk reproduction period and were then switched to 24L:0D lighting for 2 wk before collection of serial blood samples. Continuous light photostimulation was used for at least 2 wk before and during serial blood sampling to avoid potential masking effects of diurnal lighting on the interval between LH surges. The Early (n = 12) and Late (n = 16) hens were cannulated 3 days before being serially bled hourly for 10 days. The mean interval between preovulatory surges of LH was shorter in the Early hens than in the Late hens (26.1 +/- 2.5 h and 34.7 +/- 3.9 h, respectively). The intra-hen LH surge interval coefficient of variation was lower in the Early hens than in the Late hens (7.2% and 18.6%, respectively). The inter-hen LH surge interval coefficient of variation was similar in the Early and Late hens (9.5% and 11.2%, respectively). The incidence of blind surges of LH (those not retrospectively associated with ovipositions) was not different between Early and Late laying hens (8.4% +/- 15.2% and 7.3% +/- 14.6%, respectively). In conclusion, in turkey hens, longer intervals and greater intra-hen variation between LH surges were associated with a poorer rate of egg production late in the reproductive period relative to early in the reproductive period.

Animals↗
PubMed2001

Reproductive period and risk of dementia in postmenopausal women.

CONTEXT: Exogenous estrogen use may lower risk of dementia in postmenopausal women. A relationship between long-term exposure to endogenous estrogens and incident dementia has been hypothesized but not studied. OBJECTIVE: To determine whether a longer reproductive period, as an indicator of longer exposure to endogenous estrogens, is associated with lower risk of dementia and Alzheimer disease (AD) in women who have natural menopause. DESIGN AND SETTING: The Rotterdam Study, a population-based prospective cohort study conducted in the Netherlands. PARTICIPANTS: A total of 3601 women aged 55 years or older who did not have dementia at baseline (1990-1993) and had information on age at menarche, age at menopause, and type of menopause. Participants were reexamined in 1993-1994 and 1997-1999 and were continuously monitored for development of dementia. MAIN OUTCOME MEASURES: Incidence of dementia, based on Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition criteria, and AD, based on National Institute of Neurological Disorders and Stroke/Alzheimer's Disease and Related Disorders Association criteria, compared by quartiles of reproductive period among women with natural menopause. RESULTS: During 21 046 person-years of follow-up (median follow-up, 6.3 years), 199 women developed dementia, including 159 who developed AD. After adjusting for age, dementia was not clearly associated with length of reproductive period. However, after adjusting for multiple covariates, women with natural menopause and more reproductive years had an increased risk of dementia (adjusted rate ratio [RR] for women with >39 reproductive years [highest quartile] compared with <34 reproductive years [lowest quartile], 1.78; 95% confidence interval [CI], 1.12-2.84). The adjusted RR per year of increase was 1.04 (95% CI, 1.01-1.08). For risk of AD, the adjusted RRs were 1.51 (95% CI, 0.91-2.50) and 1.03 (95% CI, 1.00-1.07), respectively. Risk of dementia associated with a longer reproductive period was most pronounced in APOE epsilon4 carriers (adjusted RR for >39 reproductive years compared with <34 reproductive years, 4.20 [95% CI, 1.97-8.92] for dementia and 3.42 [95% CI, 1.51-7.75] for AD), whereas in noncarriers, no clear association with dementia or AD was observed. CONCLUSION: Our findings do not support the hypothesis that a longer reproductive period reduces risk of dementia in women who have natural menopause.

Aged↗
PubMed2005

Reproductive period and cognitive function in a representative sample of naturally postmenopausal women aged 60-64 years.

BACKGROUND: Greater lifetime estrogen exposure has been postulated to result in better cognition in later life, particularly in the area of verbal memory. In women, the highest levels of endogenous estrogen occur during their reproductive period, between menarche and menopause. OBJECTIVE: To investigate the association between reproductive period and cognition. METHODS: The sample consisted of 760 naturally postmenopausal women aged 60-64 years (mean age 62.5 +/- 1.5 years) participating in the PATH Through Life Study who were randomly drawn from the population of Canberra, Australia. Participants were administered a verbal learning test (immediate recall and 1-minute delay), the Mini-Mental State Examination (MMSE), digit span backwards, the Symbol-Digit Modalities Test and simple and choice reaction time tests. RESULTS: There were no significant associations detected between reproductive period and performance on any of the cognitive tests, either before or after controlling for potential confounding variables. CONCLUSIONS: Reproductive period, a surrogate measure of endogenous estrogen exposure, had no detectable effect on cognitive performance in this sample.

Australia↗
PubMedDate not supplied

[Evolutionary stability in the dynamics of populations having short reproduction periods].

A special class of models of competition (D-systems) were constructed in which the coefficients of population growth are periodic delta-functions. Effective methods for the analysis of the global dynamics of D-systems were proposed. In the framework of this model system, the problem of the existence of evolutionarily stable parameters, the periods of reproduction of populations in a variable medium, was studied. Using analytical methods and the data of computer-assisted experiments, open sets of evolutionarily stable parameters were found.

Animals↗
PubMed2005

Duration of the reproductive period decreases the frequency of preovulatory luteinizing hormone surges in heavy weight-sire line turkey hens.

The frequency of preovulatory luteinizing hormone (LH) surges is an important determinant of ovulation and oviposition rates in turkeys. Egg production rate is relatively poor in heavy weight-sire line type turkey hens and declines with advancing duration of the reproductive period. The purpose of this study was to measure frequency and characteristics of preovulatory LH surges in turkey hens of a heavy weight-sire line type early, at peak of egg production (Early), and late, after egg production rate had declined (Late), in a reproductive period. The Early hens were photostimulated with a continuous photoperiod [24 h light (L):0 h dark (D)] at 40 weeks of age and sampled during peak egg production at about 47 weeks of age. The Late hens were photostimulated at 40 weeks of age with a long day photoperiod (14L:10D). After a 27-week egg production period, the Late hens were switched to the 24L:0D photoperiod and sampled at 74 weeks of age. Continuous lighting was used during blood sampling to allow the rhythm of preovulatory LH surges to free run. All hens were cannulated 3-5 days before starting sampling and hourly blood samples were collected for 200 h. All hens were necropsied and ovarian and oviductal morphologies were measured after serial bleeding. The Late hens had a longer interval between intra-clutch preovulatory LH surges than the Early hens, and a higher incidence of atretic ovarian follicles. The Early hens had higher baseline and surge amplitude LH concentrations but lower progesterone (P4) surge amplitude concentrations than the Late hens. The duration of preovulatory LH surges, incidence of "blind" preovulatory LH surges, baseline P4 concentrations, and overall estradiol-17beta (E2) concentrations were not different between Early and Late hens. In conclusion, a longer interval between preovulatory LH surges, lower LH baseline and surge amplitude concentrations, a higher incidence of atretic follicles, and higher P4 surge amplitude concentration were associated with the decline in egg production late in the reproductive period in a heavy weight-sire line of turkey hens.

Aging↗
PubMedDate not supplied

Time-related trends of age at menopause and reproductive period of women in a Chuvashian rural population.

OBJECTIVE: The objective of this study was to examine in an observational, cross-sectional, community-based study the secular trend of age at menopause among women in a rural Chuvashian population and to identify factors associated with age at menopause. DESIGN: The sample included 316 postmenopausal women born between 1920 and 1950 with mean age at menopause of 48.47 +/- 4.63 (34-58) years. Statistical analyses included simple and multiple linear regression and "whiskers" plots. RESULTS: Significant association was found between year of birth and age at menopause (beta = 0.194, P < 0.001) and reproduction period (P = 0.193, P < 0.001). Mean values of age at menopause increased from 47.0 years (born during 1920-1925) to maximal values of 49.7 years (born during 1940-1945) and 49.3 years (born during 1945-1950). Mean values of their reproductive period increased from 30.7 (born during 1920-1925) to maximal values of 34.1 (born during 1940-1945) and to 33.7 (born during 1945-1950). Multiple linear regression analysis demonstrated that year of birth was the only statistically significant (P = 0.19, P < 0.01) predictor of age at menopause. Age at menarche can also be a possible predictor of age at menopause (beta = -0.12, P = 0.04). CONCLUSIONS: The study confirmed certain secular trends of age at menopause and reproductive periods in Chuvashian women. The authors also observed a negative association between age at menarche and age at menopause. The number of children and medical abortions as well as body mass index showed no association with age at menopause.

Adult↗
PubMed2005

The effect of long non-reproductive periods on the genital health in captive female white rhinoceroses (Ceratotherium simum simum, C.s. cottoni).

White rhinoceroses suffer from a low reproductive rate in captivity. Intensive efforts to propagate specifically the northern white rhinoceros have been very limited. The dismal outlook for this subspecies in the wild makes successful ex situ breeding programs paramount. In this context, this study examined 48 southern and 6 northern white rhinoceroses using ultrasound and faecal hormone analysis to elucidate causes for female reproductive failure and to determine whether long non-reproductive periods have a detrimental impact on genital health. Results showed that 76% of the nulliparous females had intact hymenal membrane indicating these females had never been bred, at an age when their wild counterparts have delivered multiple offspring. Fifty-six percent of the studied population had various reproductive pathology. Cystic endometrial hyperplasia; leiomyomas of the cervix, uterus and ovary, adenoma; para-ovarian cysts and hydromucometra represent the scope of lesions identified. The stages of the lesions in nulliparous females correlated with age (r = 0.4, P < 0.05). Due to the severity of the lesions, 28% of the study population was considered post-reproductive. Therefore, the reproductive life span in some individuals was 10-20 years shorter than expected. However, in parous females the incidence of pathological lesions was significantly lower (P < 0.0001). Seventy-eight percent females studied had erratic or absent luteal activity. The hormone data corresponded with two ultrasonographic levels of ovarian activity, active and inactive, occurring within an age range of 3-19 years and 15-38 years, respectively. This suggests the lack of ovarian activity by reproductive mid-life in non-reproducing females. The accuracy of the ultrasound findings was validated by necropsy in nine animals showing a strong positive correlation (r2 = 0.9, p < 0.001). Our data suggests that the development of reproductive pathology and ovarian inactivity in white rhinoceros is an age-related consequence of long non-reproductive periods. This asymmetric ageing process of the genital organs can be prevented with the achievement of at least one pregnancy.

Animals↗
PubMed1990

Relationship between brain gonadotropin-releasing hormone and final reproductive period of the adult male sea lamprey, Petromyzon marinus.

Gonadotropin-releasing hormone (GnRH) concentrations were measured in brains of adult male sea lamprey, Petromyzon marinus, during their final reproductive period. The lampreys were collected during their upstream migration in coastal New Hampshire rivers and sampled at the trap (referred to as Group A) or they were transferred to an artificial spawning channel (referred to as Group B). Plasma estradiol and progesterone were also measured, and histological examination of the gonadal stages was done as well. The concentrations of brain GnRH and plasma estradiol fluctuated significantly through time. There was a rise in brain concentrations of GnRH coincident with an increase in temperature just prior to spawning. In addition, there was a significant progressive correlation between increasing plasma estradiol and temperature in lampreys from Group B during the period studied. These studies provide evidence for progressive seasonal relationships between changes in brain GnRH and gametogenic and steroidogenic activity of the gonads in adult male sea lampreys during their final reproductive period.

Amino Acid Sequence↗
PubMed1976

Persistence of semen quality during the reproductive period in two strains of turkeys differing in semen yield.

Semen yield, sperm concentration and frequency of bent sperm were measured during the ninth week following stimulatory lighting (in January) and correlated with similar measurements obtained 1-1/2 and 4-1/2 months later in the reproduction period for two strains of medium bodied turkeys differing in semen yield. These correlations, based on measurements made early in the reproductive period, were not large enough so that the male's subsequent performance could accurately be predicted. Strain differences were also apparent in correlation coefficients for semen yield. The correlation coefficients were larger for the strain having the smallest yeild. In general, the significant correlation coefficients between semen yield and sperm concentration were positive and those between semen yield and percent bent sperm and between sperm concentration and percent bent sperm were negative. However, the correlation coefficients tended to be low in magnitude.

Animals↗
PubMed2003

Reproductive period affects lipid composition and quality of fresh and stored spermatozoa in Turkeys.

Semen of Turkeys between 31 and 52 weeks of age was analyzed to investigate the cause of reduction in Turkey fertility at the end of the reproductive period. Sperm motility and viability, lipid concentration, fatty acid composition and lipid peroxides were evaluated on fresh spermatozoa or spermatozoa stored for 48h at 4 degrees C. Fertility of fresh semen was also evaluated. Fertility obtained with fresh semen decreased at 44-47 weeks of age. Ageing was also accompanied by a decrease in sperm viability (at 47 weeks) and later by a decrease in motility of spermatozoa (at 52 weeks). Polyunsaturated fatty acids (PUFAs) were the first lipids of fresh spermatozoa affected by age, especially n-3 and n-9 PUFAs. Changes in these PUFAs were followed by a 30% increase in lipid peroxidation at 47 and 52 weeks of age and a reduction in phospholipid content at 52 weeks. In vitro storage did not cause lipid peroxidation in sperm obtained during the first half of the reproductive period but malondialdehyde (MDA) levels significantly increased in sperm obtained during the second half of this period. In vitro storage also decreased phospholipid content of spermatozoa from 41 weeks of age, and viability and motility regardless of age. In conclusion, lipid alteration mainly originating from PUFAs peroxidation could partly explain the decrease in semen quality and fertility observed with ageing. In addition, lipid peroxidation was increased during in vitro storage of spermatozoa from older Turkeys.

Aging↗
PubMed1987

Production and glycosylation of sperm constitutive proteins in the lizard Lacerta vivipara. Evolution during the reproductive period.

From epididymal fluid samples taken at three different times during the reproductive period (early April, late April, mid-May), the soluble proteins were separated with one dimensional electrophoresis on polyacrylamide gel. Their evolution was studied: firstly quantitatively, after staining with Coomassie blue, or, for one protein (the "L" protein), by immunodetection; secondly, according to their glycosylation after transfer to nitrocellulose and treatment with a set of labelled lectins: from Wheat germ, Ricinus communis, Lens culinaris, Asparagus pea or Canavalia ensiformis, with or without use of their specific inhibitor sugars. At least 15 proteins underwent a quantitative and/or qualitative evolution, mainly during the month of April. Protein "L" (19 kDa), which is androgen dependent and which fixates on to spermatozoa during their epididymal transit, appears to be little or not glycosylated. By contrast its accumulation in the epididymal canal increases considerably during the month of April. Five other proteins proved to be especially interesting because of their evolution during this same period, notably the MW 94, 67, 35, 29 and 25.5 kDa proteins. With the exception of the 67 kDa all the others increased quantitatively. All were decisively enriched in mannose or in methyl-mannoside residues. The proteins of MW 29 and 25.5 kDa were also enriched in galactose or N-acetyl galactosamine residues. These findings are of physiological significance since they are set up concomitantly with the acquisition of maximum motility of spermatozoa in the distal segment of the epididymis, and they coincide with a very great increase in testosteronemia.

Animals↗
PubMed2005

Metformin treatment of PCOS during adolescence and the reproductive period.

Insulin resistance is a common feature of PCOS. Hyperinsulinemia has been causally linked with all features of the syndrome, such as hyperandrogenism, reproductive disorders, and metabolic disturbances. Several insulin-sensitizing agents have been tested in the management of PCOS. Metformin is the only drug currently in widespread clinical use for PCOS. In a high percentage of patients, treatment with metformin is followed by regularization of the menstrual cycle, less pronounced hyperandrogenism and cardiovascular risk factors, and some improvement in the response to therapies aimed at induction of ovulation. In adolescent girls who are anovulatory and moderately obese, metformin administration can have a normalizing effect on multiple aberrations within the endocrine-metabolic status. During the reproductive period, metformin administration can improve reproductive function and the establishment of pregnancy. A role of metformin in prevention of gestational diabetes and hypertensive complications of pregnancy has yet to be shown. Finally, any real benefit of insulin-lowering treatment in terms of lesser cardiovascular risk in women with PCOS women remains to be demonstrated.

Adolescent↗
PubMed1980

[Somatic embryogenesis of certain Spongillidae during the reproductive period of their life cycle].

Development of small fragments taken from the body of some Spongillidae (Halichondria panicea, Spongilla lacustris) was studied during various periods of their reproductive cycle. Reconstructive morphogenesis of fresh-water sponges from small pieces of their body tissue took 5-7 days and did not depend on the stage of the reproductive cycle in the maternal organism. Form-restoring potentials in marine reproductive sponges were different. The least potentials for the development into new species were noted in the fragments containing oocytes at stages of vitellogenesis, embryos and larvae. The sponge fragments having embryos and larvae perished before they began to develop. Restorative morphogenesis of the fragments having oocytes at the stage of vitellogenesis lasted two months, while the development of the fragments having oogonia and oocytes at early stages of development transformed into a young sponge during two weeks. The fate of oocytes, embryos and larvae under conditions of restorative morphogenesis was different: oogonia and oocytes at early stages of development were preserved, while oocytes at the stage of vitellogenesis and embryos were mostly resorbed. Most of larvae completed their embryogenesis, however, if they were lesioned, external and internal larval cells could participate in the restorative process.

Animals↗
PubMed1982

Body weight changes during the reproductive period in four strains of turkey hens.

Body weight changes were taken at eight times during a 180-day reproductive period in four lines of turkey hens differing by up to 32% in body weight and 82% in egg production. The same pattern of change in body weights was observed in all four lines, indicating that body weight changes during reproduction in turkey hens are not associated with mature body weights or egg production potential.

Animals↗
PubMed2000

Pollen coupling of forest trees: forming synchronized and periodic reproduction out of chaos.

Many of the tree species in mature forests show masting; their reproductive activity has a large variance between years and is often synchronized between different individuals. In this paper, we analyse a globally coupled map model in which trees accumulate photosynthate every year, produce flowers when the energy reserve level exceeds a threshold, and set seeds and fruits at a rate limited by pollen availability. Without pollen limitation, the trees in the forest show independent chaotic fluctuation. Coupling of trees via pollen exchange results in reproduction being synchronized partially or completely over the forest. The whole forest shows diverse dynamical behaviors determined by the values of two essential parameters; the depletion coefficient k and the coupling strength beta. We find perfectly synchronized periodic reproduction, synchronized reproduction with a chaotic time series, clustering phenomena, and chaotic reproduction of trees without synchronization over individuals. There are many parameter windows in which synchronized reproduction of trees shows a stable periodic fluctuation. For perfectly synchronized forests, we can calculate all the Lyapunov exponents analytically. They show that synchronized reproduction of all the trees in the forest can only occur when trees flower at low (but positive) levels in a significant fraction of years, resulting in small fruit sets due to outcrossed pollen limitation. This is consistent with the observation that the distinction between mast years and non-mast years is often not clear cut.

Models, Biological↗
PubMedDate not supplied

[Phenotype structure and its dynamics at different stages of the reproductive period of Proteocephalus osculatus (Cestoda: Proteocephalidae)--a parasite of catfish (Silurus glanis L.)].

Discrete variability of four P. osculatus characteristics descriptive of cestodes' major functional complexes: attachment and trophic-reproduction, was determined. Phenotypic diversity of P. osculatus from 2 samples collected at different stages of the population reproductive period was analysed. Unequal adaptation of phenotypes to the ambient conditions was hypothesised.

Adaptation, Physiological↗