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At least 1,009 records · Page 56Linked to original sources
PubMed1988

Photoperiodic adjustments in hypothalamic amines, gonadotropin-releasing hormone, and beta-endorphin in the white-footed mouse.

This study was undertaken to examine short photoperiod (SD; 8 h of light, 16 h of darkness)-induced alterations in reproductive endocrine and neuroendocrine parameters in the male white-footed mouse, Peromyscus leucopus. Exposure to SD for 8 weeks caused dramatic reductions in testis and seminal vesicle weights, decreased circulating LH and testosterone levels, and lowered the content of LH in the pituitary gland relative to those in mice under long photoperiod (LD; 16 h of light, 8 h of darkness). These changes were associated with significant increases in content of radioimmunoassayable GnRH in the mediobasal hypothalamus (MBH) and anterior hypothalamus at two time points in the light/dark cycle: 2100 h (dark phase) and 0900 h (light phase), respectively. Exposure to SD also caused an increase in radioimmunoassayable beta-endorphin in the MBH and preoptic area of the hypothalamus (POA) at 2100 h, but not at 0900 h. Mice exposed to SD also had a significantly higher metabolism of serotonin in the MBH at 0900 and 2100 h compared to mice under LD. The concentration of noradrenaline in the hypothalamus was unaffected by exposure to SD. However, the metabolism of dopamine (DA) in the POA at 0900 h was significantly increased relative to that in mice maintained under LD at this time. This increase in DA metabolism was associated with enhanced immunocytochemical staining for tyrosine hydroxylase in nerve fibers of the POA. Conversely, staining for tyrosine hydroxylase in tuberoinfundibular DA cell bodies of the arcuate nucleus was less intense under SD exposure. From these data it is concluded that exposure to SD caused regional and time-dependent alterations in the activities of hypothalamic amines (serotonin and DA) and neuropeptides (beta-endorphin and GnRH). These changes may be part of the neuroendocrine mechanism for SD-induced seasonal adaptations.

Amines↗
PubMed2002

Twenty-one day administration of dienogest reversibly suppresses gonadotropins and testosterone in normal men.

Androgen-progestin combinations are promising male contraceptive regimens. Optimization of these regimens includes the development of new progestins with more favorable biological properties. In this context we tested the effects of the progestin dienogest (DNG) on reproductive hormones and metabolic parameters in men. After a 3-wk control period, 25 men were randomly assigned to receive daily doses of 2, 5, or 10 mg DNG or placebo and 10 mg cyproterone acetate for 21 d (n = 5 subjects/group). Subjects were followed for 2 wk after cessation of hormone administration. Weekly blood samples, physical examinations, hormone and chemistry measurements, semen analysis, and sexual/behavioral assessments were performed. These parameters were compared among study groups and within each group at different time points throughout the study periods. DNG and cyproterone acetate administration resulted in profound suppression of gonadotropins and T with no change in SHBG levels. No adverse effects were detected in any subject. Hormone levels returned to baseline after stopping hormone intake. DNG is a potent suppressor of gonadotropins and T in men and does not induce adverse effects over a 21-d administration. DNG is a promising progestin to be used in clinical trials for male contraception.

Adult↗
PubMed2005

Genetic parameters of fertility in two lines of rabbits with different reproductive potential.

A Bayesian analysis with a threshold model was performed for fertility defined as a binary trait (1 = successful mating, 0 = unsuccessful mating) in two populations of rabbits of different reproductive potential and different genetic origin: Line P selected for litter size and Line C selected for growth rate. There were 20,793 records of natural mating (86.2% successful) in Line C between 1983 and 2003, and 17,548 records (80.5% successful) in Line P, between 1992 and 2003. Data related to 5,388 and 3,848 females and 1,021 and 685 males in Lines C and P, respectively. The pedigree included 6,409 and 4,533 individuals in Lines C and P, respectively. The binary response was modeled under a probit approach. The model for the latent variable included male and female additive genetic effects, male and female permanent environmental effects, and the year-season and physiological status of the female (nulliparous, multiparous lactating, or multiparous nonlactating) as systematic effects. Means (standard deviation in parentheses) of the estimated marginal posterior distribution (EMPD) of male heritability were 0.013 (0.006) and 0.010 (0.008) in Lines C and P, respectively, and those of EMPD of female heritability were 0.056 (0.013) and 0.062 (0.018) in Lines C and P, respectively. Means of the EMPD of the proportion of the phenotypic variance due to environmental male and female effects were, respectively, 0.031 (0.007) and 0.128 (0.018) in Line C and 0.053 (0.010) and 0.231 (0.024) in Line P. Means (standard deviations in parentheses) of the EMPD of genetic correlation between male and female fertility were 0.733 (0.197) in Line C and 0.434 (0.381) in Line P. The posterior distribution of genetic correlations presents a huge dispersion, and the estimates should be taken with caution because of the almost negligible estimate of the male genetic component. Results indicate that little genetic variation exists for female fertility, and practically none for male fertility. It would, therefore, be possible to improve reproductive performance by including female fertility in a breeding program, but response to selection would be very small.

Animals↗
PubMed1999

Reference intervals and physiologic alterations in hematologic and biochemical values of free-ranging desert tortoises in the Mojave Desert.

Desert tortoise (Gopherus agassizii) populations have experienced precipitous declines resulting from the cumulative impact of habitat loss, and human and disease-related mortality. Evaluation of hematologic and biochemical responses of desert tortoises to physiologic and environmental factors can facilitate the assessment of stress and disease in tortoises and contribute to management decisions and population recovery. The goal of this study was to obtain and analyze clinical laboratory data from free-ranging desert tortoises at three sites in the Mojave Desert (California, USA) between October 1990 and October 1995, to establish reference intervals, and to develop guidelines for the interpretation of laboratory data under a variety of environmental and physiologic conditions. Body weight, carapace length, and venous blood samples for a complete blood count and clinical chemistry profile were obtained from 98 clinically healthy adult desert tortoises of both sexes at the Desert Tortoise Research Natural area (western Mojave), Goffs (eastern Mojave) and Ivanpah Valley (northeastern Mojave). Samples were obtained four times per year, in winter (February/March), spring (May/June), summer (July/August), and fall (October). Years of near-, above- and below-average rainfall were represented in the 5 yr period. Minimum, maximum and median values, and central 95 percentiles were used as reference intervals and measures of central tendency for tortoises at each site and/or season. Data were analyzed using repeated measures analysis of variance for significant (P < 0.01) variation on the basis of sex, site, season, and interactions between these variables. Significant sex differences were observed for packed cell volume, hemoglobin concentration, aspartate transaminase activity, and cholesterol, triglyceride, calcium, and phosphorus concentrations. Marked seasonal variation was observed in most parameters in conjunction with reproductive cycle, hibernation, or seasonal rainfall. Year-to-year differences and long-term alterations primarily reflected winter rainfall amounts. Site differences were minimal, and largely reflected geographic differences in precipitation patterns, such that results from these studies can be applied to other tortoise populations in environments with known rainfall and forage availability patterns.

Animals↗
PubMed1999

[Prognostication of reproductive disorders in women living under different ecologic conditions].

Sensitivity of females to environmental hazards is known to increase extremely during pregnancy. The harmful effects could appear not only in mother, but also in fetus. Thus, special importance is associated with materials about effects of environmental hazards in industrial agglomeration on female reproductivity. The authors demonstrate relationships of incidence and severity of female reproductive disorders, neonatal health with actual jeopardy of ecological hazards characteristic for industrial agglomeration of Volgograd region. The data obtained help to consider reproductive and neonatal health parameters which are highly prone to anthropogenous factors and to use those parameters for forecasting the pathologic conditions dependent on ecologic matters. The results could serve as a base for prognosis on demographic situation in Volgograd region by the beginning of XXI century.

Adolescent↗
PubMedDate not supplied

[Comparative study of properties of temperate erwiniophages 49 and 59].

Molecular-biological properties of two relative temperate erwiniophages 49 and 59 have been comparatively studied. The both phages are highly specific with respect to sensitive bacteria and lyse only inconsiderable quantity of amylovora-like strains of Erwinia horticola. It has been established that erwiniophages are distinguished by the basic parameters of a single reproduction cycle in the cells of common host E. horticola 450. Considerable differences between phages have been also found in the areas of genomes responsible for the establishment and maintenance of lysogenic state in the cells of the bacterium-host. Study of structure polypeptides has confirmed the identity of capsids and tails of phages 49 and 59. It has been shown that phage 49 has another, as compared to phage 59, basal plate, which availability destabilises the phage tail and leads to virion destruction under various physical effects. Virion DNA of phages 49 and 59 are of the same size--47.9 kbp, but differ as to GC-content. Using the restriction analysis it has been shown that genome of phage 49, as well as the genome of phage 59, is permuted, but its permutation is of discrete character. The fact of recombination interaction between erwiniophages 49 and 59 has been established. It is supposed that phage 49 is the recombination (hybrid) derivative of phage 59 and unknown phage, or prophage, genetic module. The given recombination, probably, took place under the persistence of different phages in the general polylysogenic system of E. horticola.

Bacteriophages↗
PubMed2003

[Preliminary study on measurement of human fecundity applicability of time to pregnancy with Japanese subjects].

BACKGROUND: Debate has been continuing whether endocrine disrupting chemicals (EDC) in the environment affect human reproduction. We are planning to use time to pregnancy (TTP) as a measure of human fecundity to relate EDC exposure in a future research. TTP is expressed as the number of non-contracepting menstrual cycles or months required for a couple to conceive. An extended TTP might be considered to reflect an injury to reproductive processes. Since this parameter has never been measured in Japan. the present preliminary study aimed at establishing a Japanese version of the TTP questionnaire and determining if TTP could be reliably measured in Japan. METHODS: We prepared a self-administered questionnaire that consisted of questions on TTP, sexual life and dietary habits. Women who visited a gynecology clinic in Tokyo for confirmation of pregnancy during the period October 2000 to March 2001 were the subjects asked to fill in the questionnaire. The results were statistically analyzed by chi-square test, t-test and binorminal logistic model after classifying the subjects into two groups: (a) Group I (TTP < or = 6 months; n = 53) (b) Group II (TTP > 6 months; n = 16) RESULTS: Of the 92 women approached, 69 (75.0%) could report TTP. The distribution of TTP, the mode being around 1-2 months with a positive skew toward longer value, was similar to those reported so far in Western countries. There were statistically significantly more smokers in Group II (smoker 62.5%) than in I (15.6%). Logistic regression analysis indicated prior gravidity and fish and milk consumption, in addition to cigarette smoking, to be related to TTP. CONCLUSIONS: The present preliminary study indicated that TTP surveys are feasible with Japanese based on the high response rate and plausible distribution of reported value. It also indicated that TTP was related to cigarette smoking, gravidity and dietary habits, again consistent with previous studies.

Adult↗
PubMedDate not supplied

[Immune male infertility: correction with efferent therapy].

Effects of plasmapheresis and hemosorption on efficacy of the treatment of autoimmune male infertility (AMI) were studied in 289 AMI males with oligoasthenozoospermia aged 19 to 37 years. The males were divided into three groups by the levels of antisperm antibodies (ASAB) in the blood and ejaculate. The study was made of cellular and humoral immunity, intensity of protein and lipid free radical oxidation and antioxidant defense. Patients of group 1 with high ASAB in the blood but low in ejaculate received a course of plasmapheresis. Patients of group 2 with high ASAB both in the blood and ejaculate were subjected to hemosorption and plasmapheresis in one contour. Group 3 patients with high ASAB in ejaculate but low in the blood received efferent therapy only after medication and photomodification of the blood. The treatment reduced elevated levels of ASAB in the blood and ejaculate, normalized free radical oxidation, cellular and humoral immunity, antioxidant defense. This resulted in improvement of spermogram parameters, efficacy of assisted reproductive technologies, higher probability of natural pregnancy in the patients' wives.

Adult↗
PubMed2006

Czech Teratology Information Service: comparison of treatments by psychotropic and antiepileptic drugs.

OBJECTIVES: Care, treatment and follow-up in psychiatric and epileptic pregnant women were compared with women inquiring Czech Teratology Information Service (CZTIS) due to other exposure to drugs during pregnancy. METHODS: Data were collected by CZTIS, member of European Network of Teratology Information Services from 1996. Exposed groups were compared with pregnant women exposed to drugs which were not classified as major teratogens or hyperthermia. Groups do not vary in age, reproductive history and other parameters. RESULTS: We observed higher frequency of miscarriage and voluntary termination of pregnancy in the group of psychiatric patients. The number of malformation in prospective follow-up cases was lower than in control group. CONCLUSIONS: Chronic diseases as epilepsy or psychiatric disorders have to be treated during pregnancy. Women should obtain accurate information about possible risk before pregnancy. Co-operation is needed in these cases. Physicians should keep in mind that appropriate information is to be given to the patient according to her disease, education and comprehension of the problem. If there is any doubt they should organize help for their patients.

Anticonvulsants↗
PubMed1987

[Hyperandrogenemia as a cause of amenorrhea].

The so-called postpill amenorrhea remains a much debated subject in gynecological endocrinology. We have therefore scrutinized the reproductive history and endocrinological parameters of 145 patients with the presumptive diagnosis of postpill amenorrhea, seen at our department during the last two years. 166 cases of secondary amenorrhea served as a control group. Both groups showed a high incidence of late menarche (20%), previous oligomenorrhea and elevated androgen serum levels. There were no significant differences between both collectives. These findings suggest that although oral contraceptives may unfavorably influence the menstrual cycle, there is no causal relationship between such agents and the development of secondary amenorrhea. It seems that in many cases of presumptive postpill amenorrhea the common juvenile hyperandrogenemic ovarian insufficiency might be the underlying problem.

Adolescent↗
PubMedDate not supplied

[Locomotion of human circulating lymphocytes methodological aspects "in vitro" (author's transl)].

Locomotor activity of lymphocytes from human peripheral blood towards the chemoattractant casein was examined in vitro in modified Boyden chambers with a single micropore filter (according to the Wilkinson's method), and in Keller's chambers with two micropore filters. Using the single filter technique, this paper reports the precise standard parameters necessary for a reproductive assay, that is a filter of 5 micron pore size (Millipore), an incubation of 5 h with 5 mg/2 ml of alpha-casein, and the counting of lymphocytes at the front of migration within the filter. The distinction between the chemotaxis (directional locomotion) and the chemokinesis (random migration) in the presence of the alpha-casein was confirmed with human circulating lymphocytes. When the results obtained with the double filter technique are compared with that of single filter, Keller's method shows no advantage over the single filter technique modified by Wilkinson. The latter appears adequate to study specific and non-specific drug-induced lymphocyte chemotaxis and chemokinesis with normal or pathological cells in man.

Caseins↗
PubMedDate not supplied

[Effect of low temperatures on molecular parameters of DNA].

Cryoconservation effects on macromolecular parameters of DNA from reproductive cells of fishes are studied as well as cryodamages of DNA in solutions under various freezing conditions, by the viscometry method. A dependence of the low temperature action on DNA concentration in solution and on the action duration is determined. It is stated as well that the nitrogen temperature action on the biopolymer solution results in the formation of both double- and single-stranded breaks. The cryoprotector (ethylenglycol 12%) added into the solution frozen prevents from the formation of double-stranded breaks and decreases the number of single-stranded ones. The long-term (0.5 year) keeping of the biopolymer solution at -196 degrees C both under the cryoprotector (20% 1.2-propanediol) protection and without the cryoprotector induces the significant number of single-stranded breaks. Mechanisms of cryodamages of DNA macromolecules in cells and under the nitrogen temperature action are discussed.

Animals↗
PubMed2004

Effects of human and murine antisense oligonucleotide inhibitors of ICAM-1 on reproductive performance, fetal development, and post-natal development in mice.

The potential for reproductive toxicity of an antisense oligonucleotide designed to inhibit ICAM-1 was evaluated as part of the safety assessment for this compound. Since antisense compounds are often specific to the species in which they are intended to work, both the human and murine active ICAM-1 inhibitors were tested (ISIS 2302 and ISIS 3082, respectively). Male and female mice were treated prior to cohabitation, through cohabitation, gestation, delivery, and weaning. Mice were treated with 0, 3, 6, and 12 mg/kg ISIS 2302 or ISIS 3082 by daily i.v. injection. Reproductive indices evaluated included estrus cycling, sperm count and motility, fertility, litter parameters, fetal development, delivery, fetal body weight, lactation, and weaning. Behavioral assessment and reproductive capacity of the F1 generation mice was assessed on selected animals. Concentrations of oligonucleotide in selected maternal target organs, placenta, fetal tissues, and expressed milk were also measured. There were no changes in reproductive performance, litter parameters, fetal development, or postnatal development in mice treated with either ISIS 2302 or ISIS 3082. Maternal liver and kidney contained dose-dependent concentrations of oligonucleotide, but there was relatively little or no oligonucleotide measured in placenta, fetal tissues, or expressed milk. Neither the human nor murine-specific antisense inhibitor of ICAM-1 produced any reproductive toxicity in mice, and exposure of fetus or pups was negligible.

Animals↗
PubMed1974

Demographic parameters and natural selection.

This paper introduces two new demographic parameters, the entropy and the reproductive potential of a population. The entropy of a population measures the variability of the contribution of the different age classes to the stationary age distribution. The reproductive potential measures the mean of the contribution of the different age classes to the growth rate. Using a relation between these measures and the Malthusian parameter, it is shown that in a random mating population in Hardy-Weinberg equilibrium, and under slow selection, the rate of change of entropy is equal to the genetic variance in entropy minus the genetic covariance of entropy and reproductive potential. This result is an analogue of Fisher's fundamental theorem of natural selection.

Gene Frequency↗
PubMed2000

Physiological perturbations in several generations of Daphnia magna straus exposed to diazinon.

Daphnia magna was exposed to sublethal diazinon concentrations (0.05, 0.1, 0.5, 0.75, and 1.0 ng/L) for 21 days. The algae Nannochloris oculata (5x10(5) cells/mL) was used to feed the daphnids. Chronic toxicity tests were carried out using neonates of F(1) (first brood) and F(1) (third brood) offspring generations from parentals (F(0)) preexposed to the organophosphate. The effect of diazinon on survival, reproduction, and growth was monitored for the selected daphnid generations. The parameters used to evaluate pesticide effect on reproduction were mean total young per female, mean brood size, time to first reproduction, mean number broods per female, and intrinsic rate of natural increase (r). Survival and growth (body length) were also determined after 21 days of exposure to the pesticide. Reproduction as well as survival was significantly reduced when diazinon concentration increased in the medium. This effect was greater in F(1) (first) and F(1) (third) offspring compared to the parental generation (F(0)) daphnids. The intrinsic rate of natural increase (r) decreased with increasing concentrations of diazinon, especially in those animals from the first and third brood. However, the growth of the exposed organisms decreased in the same order of magnitude in all generations tested. The maximum acceptable toxicant concentration (MATC) was calculated for F(0), F(1) (first), and F(1) (third) generations of D. magna exposed to the pesticide using as parameter of evaluation the intrinsic rate of natural increase (r). The interpolation of these results gave MATC values of 0.62 and 0.07 ng/L pesticide for F(0)-F(1) (first) generations and F(1) (third) generation, respectively. Therefore, F(1) (third) generation seems to be more sensitive to diazinon than generations F(0) and F(1) (first). The EC(50) values have been derived for some selected parameters on the generations of D. magna exposed to diazinon. EC(50) values decreased in F(1) (first) and F(1) (third) generations compared to the parental generation F(0). Expanding the reproduction tests to several generations revealed important information on chronic toxicity that could add to an increased cost-effectiveness in the protection of aquatic environments.

Animals↗
PubMed2005

Quantitative characteristics of Atlantic halibut, Hippoglossus hippoglossus L., semen throughout the reproductive season.

The overall objective of the study was to investigate changes in quantitative parameters of Atlantic halibut (Hippoglossus hippoglossus L.) semen throughout the reproductive season in order to systematize the knowledge about biology of Atlantic halibut spermatozoa. Semen samples were collected from February to May from broodstock males kept under either a natural or 3-month advanced photoperiod regime. Spermatozoa concentration, semen pH and osmolality, as well as spermatozoa motility parameters were investigated. The use of catheterization of sperm was examined. Also, fertilization tests were performed. We found that spermatozoa concentration increases in a linear-like mode towards the end of the spawning season, which correlated with a decrease in a number of spermatozoa motility parameters, including actual percentage of motile spermatozoa (MOT), curvilinear velocity (VCL) and straight-line velocity (VSL) of spermatozoa. A breakpoint in MOT occurred when spermatozoa reached a concentration in the range of 17-20 x 10(9) spermatozoa/mL. The fertilization ability of sperm from males kept under natural photoperiod decreased in April. Survival of embryos at 80 degrees days produced by fertilizing eggs of single female with sperm from natural photoperiod males was 88, 76 and 41% on April 09 and 17, and May 01, respectively, whereas using sperm from 3-month delayed photoperiod males for fertilizing eggs from the same female on April 27 resulted in 80% of surviving embryos, not differing significantly from the data from April 09. Physical decomposition of spermatozoa was observed towards the end of the season and it was related to an increase in the whole semen osmolality. Catheterization of semen did not improve spermatozoa motility parameters, however, it reduced the variation in recorded values, especially in the case of pH, caused by contamination with feces or urine. Post-seasonal decrease in spermatozoa concentration was likely related to intensive ageing processes. Based on the present study and available data by other researchers, a model of changes of quantitative parameters in Atlantic halibut semen throughout the reproductive season is proposed.

Animals↗
PubMed1990

Maximum likelihood estimation of the parameters of the prior distributions of three variables that strongly influence reproductive performance in cows.

Ovulation detection rate, pregnancy rate, and embryo loss rate greatly affect the reproductive performance of cows. A previous model described the separate effects of these variables on the resulting calving patterns and assumed that the variables have the same value for all cows belonging to the same herd. This is not a realistic biological assumption, so the beta distribution is used to introduce "between-cow" variation in the three variables. Two approaches are used to find maximum likelihood estimates of the parameters of these prior beta distributions. The first considers sequences of ovulations, artificial inseminations, and pregnancies, separately. For both ovulation detection rate and pregnancy rate this approach considers the number of "successes" of each event for a particular cow (e.g., in the case of an ovulation, a success is a detection), and conditions on the total number of occurrences of that event in the cow, so that beta-binomial distributions are considered. However, for embryo loss rate the number of pregnancies required until a particular cow calves is considered, so that a beta-geometric distribution results. If the cow is removed before she calves, a censored sequence will result. The second approach considers the sequences of ovulations, artificial inseminations, pregnancies, and embryo losses, together, which will stop only when the cow calves. Otherwise, if she is removed before that time, a censored sequence will result. In this case, a joint distribution, with three independent prior beta distributions, is considered. The results of the analysis of data from 22 herds are discussed.

Animals↗