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Results for “Reproductive parameters”

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At least 1,063 records · Page 59Linked to original sources
PubMed1992

Two-generation reproduction study of hydrotreated shale oil vapors.

Two generations of Sprague-Dawley rats were each exposed to vapors generated by countercurrent distillation (50 degrees C) at 0, 0.5, 2.5, and 5.0 mg/liter, for 6 hr/day, 5 days/week, for 124-126 days prior to mating. After mating, exposure was continuous except for the last day of gestation through lactation for F0 dams, and the last day of gestation through Day 6 of lactation for F1 dams. F1 pups were not exposed during lactation; F2 pups were exposed via nursing only. Body weights were recorded weekly before mating; organ and body weights were recorded on Days 1, 13, and 30 of gestation and on Days 1, 4, and 21 of lactation. Histopathology, reproductive performance, and certain sperm parameters were evaluated. The test material significantly (p less than 0.05) depressed body weights of F0 males and brain and lung weights of F1 weanling males at 5.0 mg/liter. Testicular weights of F1 weanling males were depressed at the 0.5 and 5.0 mg/liter concentrations. While a dose-related decrease in sperm count and sperm ATP levels and an increase in ATP/sperm ratios were observed in F0 males at 2.5 and 5.0 mg/liter, there was no adverse effect on overall reproductive performance.

Animals↗
PubMed1985

Comparison of transformation, chromosome aberrations, and reproductive death induced in cultured mammalian cells by neutrons of different energies.

Dose-effect relations for cell transformation and reproductive death induced in C3H/10T1/2 cells, NBCH-3 cells, and WAGR-2 cells by 300 kV X rays and monoenergetic fast neutrons of 0.5, 4.2, and 15 MeV energy have been analyzed on the basis of the relations F(D) = t1D + t2D2 and S(D)/S(0) = exp - (a1D + a2D2), respectively. Values of a1 are a factor of about 10(3) larger than corresponding values of t1, while the dependence on neutron energy is similar for both effects. RBE values and relations between the a1 and t1 values are compared with characteristics, derived from corresponding parameters for chromosome aberrations and reproductive death, induced in other cell lines after irradiation with the same neutron beams. A hypothesis is developed assuming that nonrandom structural changes at a restricted number of sites on one or more chromosomes are the primary causes of transformation of cultured mammalian cells by ionizing radiations, whereas similar but randomly distributed chromosomal changes, which are induced at many sites on all chromosomes, cause observable aberrations and reproductive death. Flow cytometry of chromosome suspensions has been used to demonstrate nonrandom changes of chromosomes in selected clones of transformed cells and of random changes of chromosomes in cells inactivated by X rays and neutrons.

Animals↗
PubMed2003

Long-term fitness consequences of female extra-pair matings in a socially monogamous passerine.

Whether female birds choose extra-pair mating partners to obtain genetic fitness benefits is intensely debated. The most straightforward and crucial test of 'good genes' models of female extra-pair mating is the comparison of naturally 'cross-fostered' maternal half-siblings sharing the same rearing environment as any systematic differences in performance between the two categories of offspring phenotype can be attributed to differential paternal genetic contribution. We analysed local recruitment and first-year reproductive performance of maternal half-siblings in the coal tit (Parus ater), a passerine bird with high levels of extra-pair paternity. We provide a highly comprehensive measure of the long-term fitness consequences of female extra-pair matings based on a large sample of 736 within-pair offspring (WPO) and 368 extra-pair offspring (EPO) from 91 first and 55 second broods, from which 132 breeders recruited into the study population. In contrast to predictions derived from 'good genes' models, we found no differences in local recruitment and seven parameters of first-year reproductive performance when comparing WPO and EPO. These results question the universal validity of findings in other bird species supporting 'good genes' models, particularly as they are based on the best approximation to female fitness obtained so far.

Animals↗
PubMed1987

[Effect of a static magnetic field (3.5 T) on the reproductive behavior of mice, on the embryo and fetal development and on selected hematologic parameters].

To investigate possibilities of magnetic resonance imaging at high magnetic fields in humans, a whole-body magnet with a magnetic field density of 4 T was developed. Due to the few data that are available at present on biological effects and side effects of such high fields, a reproduction experiment with NMRI mice was performed using a crossover design. The mice were allowed to mate during a 7-day period within the field or after their stay in the field. The number of pregnant mice and foetuses were recorded and compared to the controls. Another group was held within the magnetic field during the whole period of pregnancy until day 18, one day before delivery. In all groups, development of the foetuses was studied. Additionally, haematological parameters of the males and females were estimated and necroscopy was performed. Brains, lungs and optical nerves were investigated using pathohistological techniques. It could be shown that in case of mating within the magnetic field, the number of pregnant mice was considerably reduced. This effect was, however, completely reversible if mating occurred after the stay in the field. Malformations, retardations or an increased number of resorptions were never found. The haematological parameters were, in general, not changed. Necroscopy as well as pathohistological investigations showed no pathological alterations. Therefore, it appears that whereas high magnetic fields reduce the activity of mating behaviour, they do not exert any influence on physiological parameters.

Animals↗
PubMed1990

[Reproductive and developmental toxicity study of mofezolac (N-22) (4)--Study by oral administration of N-22 during the perinatal and lactation periods in rats].

peri- and postnatal study of mofezolac (N-22), a new developed analgesic and anti-inflammatory agent, was carried out with Wistar rats. N-22 at dose levels of 0, 25, 50 and 100 mg/kg/day were administered orally to pregnant and subsequent delivered dams from day 17 of gestation through day 21 of lactation. Body weight gains of dams treated with 50 and 100 mg/kg/day were depressed during perinatal period. Prolongation of pregnancy period, low performance of pup care with decrease in body weights and food consumptions were observed in 100 mg/kg/day group. Decrease in number and birth index, increase in number of stillborns and tendency to decrease in viability index on day 4 were found in 100 mg/kg/day group. Other parameters of development, behavior or reproductive capability of F1 animals showed no changes related to administration of N-22. It was suggested that no effect dose levels of N-22 were 25 mg/kg/day for dams viewpoint of general toxicity and that was 50 mg/kg/day for dams on reproductive performance and for offspring on development.

Administration, Oral↗
PubMed1989

Survival, growth and reproduction of Daphnia carinata (Crustacea: Cladocera) exposed to chronic cadmium stress at different food (Chlorella) levels.

In nature, organisms have to respond to a diversity of factors acting simultaneously. The present investigation was conducted to study whether changes in food (Chlorella) levels could modify the chronic toxicity of cadmium on the various life-history parameters, such as survivorship, longevity, life expectancy, fecundity, age at first reproduction, R(0), T, r and growth rates of the cladoceran Daphnia carinata. The study indicated that at low food levels (0.5 x 10(6) cells ml(-1) Chlorella), cadmium concentrations in the range of 27-162 microg litre(-1) reduced these life-history parameters by 50% (EC(50)). At medium food levels (1.5 x 10(6) ml(-1) Chlorella) the EC(50) of cadmium was in the range of 51-127 microg litre(-1). At high food levels (4.5 x 10(6) cells ml(-1) Chlorella), the toxic effect of cadmium was greatly reduced. The decreases in survival, growth and reproduction of D. carinata at high cadmium-low food levels affected the fitness parameter 'r'. The study emphasises the need to include reproductive parameters other than mere survival in toxicity bioassays. The study also stresses the need to incorporate in laboratory tests other relevant factors that might modify pollutant toxicity.

Journal Article↗
PubMedDate not supplied

Mode of action: impaired fetal leydig cell function--effects on male reproductive development produced by certain phthalate esters.

Certain phthalate esters (di-2-ethylhexyl; di-n-butyl and butyl benzyl) have profound effects on the developing male reproductive system when administered orally to pregnant experimental animals during a critical window of development. These esters produce a syndrome of adverse effects that are characteristic of a disturbance in androgen-mediated development and include a variety of reproductive tract malformations and effects on developmental phenotypic markers. A testicular dysgenesis syndrome has been proposed to explain the secular increases in a number of human male reproductive deficits, including decreased semen parameters, increased incidence of cryptorchidism and hypospadias (two of the most common human birth defects), and increased incidence of testicular (germ cell derived) cancer. The rodent phthalate data lend support to the hypothesis. This example illustrates a number of points in the use of the Human Relevance Framework. First, chemical agents may have more than one mode of action (MOA): for example, phthalate-induced peroxisome proliferation leading to hepatocarcinogensis, compared with the induction of developmental effects via effects on androgen signaling. Second, the case demonstrates the life-stage sensitivity of the response to these compounds. Third, because humans may be exposed to multiple phthalate esters producing adverse effects on reproductive development, these compounds may be useful in testing the utility of the Human Relevance Framework (HRF) approach for evaluating cumulative and aggregate risk.

Abnormalities, Drug-Induced↗
PubMed1995

Use of postseparation sperm parameters to determine the method of choice for sperm preparation for assisted reproductive technology.

OBJECTIVE: To evaluate strict sperm morphology after preparation of semen specimens using three different sperm separation techniques, since strict morphology correlates well with IVF. DESIGN: Semen from 30 men were analyzed before and after sperm separation using mini-Percoll gradient, direct swim-up, and SpermPrep filtration column (ZBL, Inc., Lexington, KY) methods. SETTING: Assisted Reproductive Technology laboratory at Sinai Hospital of Baltimore. MAIN OUTCOME MEASURES: Primary end points measured were percent morphologically normal sperm and percent improvement in sperm morphology, using Kruger strict criteria. Secondary factors determined were percent motility, improvement in motility, hypoosmotic swelling, improvement in hypoosmotic swelling, and 24- and 48-hour sperm survival under simulated IVF conditions. RESULTS: Mini-Percoll produced specimens with significantly greater normal sperm morphology, morphology improvement, motility, hypoosmotic swelling, and survival than obtained with the other two separation methods. For 25 of 30 specimens, mini-Percoll yielded the greatest number of morphologically normal, motile sperm that survived for 24 hours. In four instances, mini-Percoll was associated with an increased percentage of acrosomal abnormalities despite an overall improvement in morphology. Hypoosmotic swelling scores were lower in two subjects after mini-Percoll sperm separation and in three subjects for each of the other methods. CONCLUSIONS: Data suggest that mini-Percoll is superior to swim-up or SpermPrep for producing specimens with enhanced morphology, motility, and in vitro survival. However, no single separation technique is always superior, and methodology may induce damage to the acrosome or sperm membranes. Sperm specimens should be evaluated individually to determine the best separation method before actual ART cycles. The technique that yields the most morphologically normal, motile sperm that survive in culture should be used for ART procedures.

Cell Separation↗
PubMed2006

Reproductive biology and mating system estimates of two Andean melocacti, Melocactus schatzlii and M. andinus (Cactaceae).

BACKGROUND AND AIMS: The genus Melocactus comprises 36 species of globose cacti with the most derived traits in the Cereeae tribe. It is the proper study system to examine what are the most derived reproductive strategies within that tribe. This study aims to characterize the reproductive biology and to estimate the mating system parameters of two Andean melocacti, Melocactus schatzlii and M. andinus. METHODS: The reproductive attributes of the two species were described, including floral morphology, anthesis patterns, floral rewards, floral visitors and visitation patterns. Levels of self-compatibility and autonomous self-pollination were estimated by hand-pollination experiments. Mating system estimates were obtained by conducting progeny array analyses using isozymes. KEY RESULTS: The flowers of the two species present the typical hummingbird-pollination syndrome. Despite their morphological resemblance, the two species differ in flower size, pollen and ovule production and anthesis pattern. Their main pollinator agents are hummingbirds, four species in M. schatzlii and one species in M. andinus. Both cacti are self-compatible and capable of self-pollination without the aid of pollen vectors. Population-level outcrossing rate was higher for M. schatzlii (t(m)=0.9) than for M. andinus (t(m)=0.4). At the family level, outcrossing rates for most mothers of M. schatzlii were higher (t(m)>0.8) than for M. andinus (t(m)<0.5). CONCLUSIONS: Although the two cacti are capable of selfing, M. schatzlii is a predominantly outcrossing species, while M. andinus behaves as a mixed-mating cactus. Hummingbirds are the only pollinators responsible for outcrossing and gene flow events in these species. In their absence, both melocacti set seeds by selfing. Based on its low population size, restricted distribution in Venezuela, low rates of floral visits, and high levels of inbreeding, M. andinus is considered to be an endangered species deserving further study to define its conservation status.

Animals↗
PubMed2005

Uterine effects of metformin administration in anovulatory women with polycystic ovary syndrome.

BACKGROUND: Metformin has been shown to improve fertility in anovulatory patients with polycystic ovary syndrome (PCOS), inducing not only a high ovulation and pregnancy rate but also reducing the incidence of miscarriages. The aim of the present study was to evaluate the uterine effects of metformin in patients with PCOS who ovulated under metformin. METHODS: Thirty-seven non-obese primary infertile anovulatory patients with PCOS and another 30 age- and body mass index-matched healthy women (control group) were studied. PCOS patients were treated with metformin (850 mg twice daily) for 6 months, whereas the control group did not receive any treatment. In these PCOS patients who ovulated whilst under metformin treatment (PCOS group) and in controls, uterine, sub-endometrial and endometrial blood flow, and endometrial thickness and pattern were evaluated using serial ultrasonographic assessments. RESULTS: Before treatment, uterine, sub-endometrial and endometrial blood flows were significantly lower in patients with PCOS than in the control group. All indexes of uterine vascularization were significantly improved in the PCOS group with metformin treatment and were not different from the controls. Nor was any difference in endometrial thickness and pattern detected between PCOS and control groups. After grouping the data of PCOS patients who ovulated under metformin for cycles with favourable/unfavourable reproductive outcome, no difference in any parameter was observed. CONCLUSIONS: Metformin improves all surrogate markers of endometrial receptivity in PCOS patients, without difference between patients who had favourable or unfavourable reproductive outcome.

Adult↗
PubMed2006

[Morpho-functional parameters of the corpus luteum in healthy women and in patients of reproductive age with uterine myoma].

Ovarian corpus luteum of menstruation at the stage of its peak activity was studied in normal women and in patients with proliferative uterine myoma using ultrasonography (intravaginal color Doppler imaging), laboratory analyses (progesterone and estrogen concentrations in peripheral blood) and morphological (histological, histochemical and morphometric) methods. In patients with proliferative uterine myoma, the defective corpus luteum was detected, as indicated by the prevalence of small granulosa lutein cells, insignificant amount and uneven distribution of lipid inclusions in their cytoplasm, marked reduction of progesterone concentration in peripheral blood, unechogenicity, low degree of vascularization and increase in the value of resistance index of ovarian stromal arteries.

Adult↗
PubMed2005

Establishing principal soil quality parameters influencing earthworms in urban soils using bioassays.

Potential contamination at ex-industrial sites means that, prior to change of use, it will be necessary to quantify the extent of risks to potential receptors. To assess ecological hazards, it is often suggested to use biological assessment to augment chemical analyses. Here we investigate the potential of a commonly recommended bioassay, the earthworm reproduction test, to assess the status of urban contaminated soils. Sample points at all study sites had contaminant concentrations above the Dutch soil criteria Target Values. In some cases, the relevant Intervention Values were exceeded. Earthworm survival at most points was high, but reproduction differed significantly in soil from separate patches on the same site. When the interrelationships between soil parameters and reproduction were studied, it was not possible to create a good model of site soil toxicity based on single or even multiple chemical measurements of the soils. We thus conclude that chemical analysis alone is not sufficient to characterize soil quality and confirms the value of biological assays for risk assessment of potentially contaminated soils.

Animals↗
PubMed2005

A two-generation reproductive toxicity study of butyl benzyl phthalate in rats.

A two-generation reproductive toxicity study with extra parameters was performed for Butyl benzyl phthalate (BBP). The compound was administered orally by gavage with the doses of 0, 100, 200, or 400 mg/kg/day to groups of 24 Crj:CD (SD)IGS rats of both sexes to confirm the utility of the protocol for identification of non-steroid chemicals with endocrine activity by ssessing effects on parental animals and offspring. Softening of the testes, diffuse atrophy of testicular seminiferous tubules, decreased spermatozoa and/or residual germ cells in the epididymal lumina were observed in the F1generation after doses more than 100 mg/kg, lowering of the F1 epididymal weights at doses more than 200 mg/kg, along with low F0 epididymal weights, Leydig cell hyperplasia, residual germ cells in the epidimymal lumina, and low seminal vesicle weights, small testes and epididymes, partial aplasia or aplasia of the epididymes, and Leydig cell hyperplasia in the F1 generation with 400 mg/kg. With regard to effects on the reproductive capacity, F1 parents at the dose of 400mg/kg showed a reduced fertility index and delayed preputial separation of the penis. In the offspring, lowered body weights in the F1 case, and change in anogenital distance in the F1 females and F2 males were observed at doses more than 100 mg/kg, with low splenic weights at 400 mg/kg in both generations. Thus, the utility of this protocol was confirmed. In the parental animals, the no observed effect level (NOEL) and the no observed adverse effect level (NOAEL) were less than 100 mg/kg/day, and no serious effects on the reproductive capacity were induced at doses less than 200 mg/kg/day. The NOEL and NOAEL for the growth and development of offspring were concluded to be less than 100 mg/kg/day.

Administration, Oral↗
PubMed2002

Effects of temperature and salinity on life history of the marine amphipod Gammarus locusta. Implications for ecotoxicological testing.

The life history of Gammarus locusta was analysed in the laboratory under the following temperature and salinity combinations: 20 degrees C-33/1000, 15 degrees C-20/1000 and 15 degrees C-33/1000 (reference condition). Life history analysis comprised survival, individual growth, reproductive traits and life table parameters. Compared to 15 degrees C, life history at 20 degrees C was characterised by at least a four-week reduction in the life-span, lower life expectancy, shorter generation time, faster individual growth, anticipation of age at maturity and higher population growth rate. These temperature effects constituted an acceleration and condensation of the life cycle, compared to the reference condition. Concerning salinity effects, with few exceptions, results show that overall this amphipod life history did not differ significantly between the salinity conditions tested. Regarding ecotoxicological testing implications, findings from this study indicate that the range of temperature and salinity conditions acceptable for testing was substantially expanded both for acute and chronic assays. A temperature of 20 degrees C or higher (for a salinity of 33/1000) is suggested for routine chronic sediment toxicity testing with G. locusta, in order to reduce the life cycle and consequently improve cost-effectiveness and standardisation. Results also suggest that a multiple-response approach, including survival, growth and reproduction, should be applied in chronic toxicity tests.

Animals↗
PubMed1991

The assessment of the behavioural teratogenic risk of the tocolytic drug phenoterol.

Phenoterol, a tocolytic drug widely used in cases of imminent preterm labour for disruption of uterine contractions, was studied for potential harmful impact on the developing fetal brain which is just going through the vulnerable period of accelerated histogenesis and cytodifferentiation. As the developmental stage of human fetus brain in late pregnancy closely resembles the ontogenetic phase of the rat brain in the early postnatal period, the model experiments were carried out using the drug administration in the neonate rat and life-long comprehensive follow-up of sequels in behaviour, reproductive functions and brain biochemical parameters. No deviations were found when phenoterol was administered in the dose 1 mg/kg/day s.c. on the postnatal days 6-9 (clinically relevant dosage). Several minor aberrations were observed after 10 times higher dose (10 mg/kg/day s.c. on postnatal days 5-7) in preweaning period (acceleration of somatic development) and in adulthood i.e. at the age of 2-7 months (higher score of emotionality). The inferiority of phenoterol treated rats became apparent only with the onset of senescence (age 11-14 months) when lower score of memory acquisition was ascertained joined with an increase of lipid peroxidation in the brain cortex.

Animals↗
PubMed2005

Reproductive success of broiler breeders in natural mating systems: the effect of male-male competition, sperm quality, and morphological characteristics.

In natural mating systems in which broiler breeder males compete for females, reproductive behavior plays an important role in male fertility, along with sperm competition and morphological and physiological characteristics. We investigated the effect of male-male competition compared with a noncompetitive situation on fertility, sperm quality, and morphological traits. Six groups of 3 males and 12 females were housed in mixed-sex pens. Their frequency of mating was recorded, and progeny of each male was determined through DNA fingerprinting. Males with the highest and the lowest mating frequencies were later placed into groups of 1 male and 4 females, their behavior was recorded, and their fertility was calculated. We collected data on semen quality (semen volume, sperm concentration, and mobility) and morphometrical characters. Finally, females were artificially inseminated with sperm from highest frequency, lowest frequency, or a mix, paternity and fertility were estimated. Our results indicate that heavier males had higher frequency of matings without cloacal contact, and males with smaller combs had more mating attempts. We also detected that males with high sperm concentration had lower fertility. However, we found an overall lack of association between mating behavior, morphometrical traits, sperm quality, and fertility. This, together with the discrepancy of results in fertility when compared with artificial insemination conditions, suggest a multifactorial nature of the fertility of broiler breeder males in natural mating systems. In addition we observed a high male fertility when housed individually, suggesting that male fertility is a relative parameter that depends upon the reproductive quality of the other male competitors within the group.

Animals↗
PubMed2001

A bit of sex stabilizes host-parasite dynamics.

To date, only a few studies have focused on the effects of sex on population dynamics. Previous models have typically found that sexual reproduction dampens population fluctuations. Although asexual and sexual reproduction are just the two endpoints along a continuum of varying rates of sex, previous work has ignored the effects of intermediate degrees of sex on population dynamics. Here we study the effects of partial sexual reproduction (i.e. sex occurs only every few generations or with small probability in each generation) on the coupled population dynamics of a Nicholson-Bailey host-parasite model. We show that complex dynamics are simplified for high host population growth rates if the frequency of sex is sufficiently high in both host and parasite: sex decreases fluctuations in population density, and leads to non-chaotic dynamics for population growth rates that would result in chaotic dynamics in the absence of sexual reproduction. However, the simplification does not increase gradually with an increasing frequency of sex but appears abruptly at low-to-intermediate frequencies of sex. For some parameter settings, intermediate frequencies of sexual reproduction can simplify the dynamics more than lower or higher frequencies. Thus, in agreement with earlier results, sexual reproduction typically stabilizes complex population dynamics in our models. Additionally, our results suggest that low-to-intermediate frequencies of sex may often be as (or even more) stabilizing as high frequencies.

Animals↗