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Results for “Reproductive parameters”

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PubMed1990

Effect of age on response to human menopausal gonadotropin stimulation.

Conception rates decline in the latter part of the reproductive years. To examine which ovarian parameters are altered with aging, 486 cycles from 225 ovulatory infertile women undergoing human menopausal gonadotropin (hMG) superovulation and washed intrauterine insemination were analyzed. Infertility factors included endometriosis (68%), unexplained infertility (8.4%), male factor (12.9%), and ovulatory dysfunction (10.7%). Parameters that demonstrated a linear relationship with increasing age included numbers of ampules of hMG required per cycle (r = 0.79; P less than 0.05), days of stimulation (r = 0.73; P less than 0.01), estradiol level at the time of hCG (r = -0.92; P less than 0.0001), number of follicles larger than 15 mm (r = -0.61; P less than 0.05), and rate of rise of estradiol (r = -0.92; P less than 0.0001). These same age-dependent changes were observed in women receiving a standard stimulation protocol (3 ampules hMG beginning on cycle day 2). When standard cycles were limited to the first cycle only, the preovulatory estradiol (r = -0.92; P less than 0.005), slope of estradiol rise (r = -0.92; P less than 0.005), and number of preovulatory follicles (r = -0.92; P less than 0.005) still showed a significant decrease with age. Although the mean estradiol level per preovulatory follicle showed a slight decrease with maternal age, no statistically significant trend was noted. In addition, the cycle day of hCG administration was unaffected by age. With advancing age, there appears to be a decreased ovarian response to an increased amount of stimulation, as measured by steroidogenesis and follicular recruitment; yet the estradiol/follicle remains unaltered, indicating continued health of the follicle. These observations may explain in part the observed decrease in fecundity in older women.

Adult↗

PubMed2001

Intramuscular testosterone undecanoate and norethisterone enanthate in a clinical trial for male contraception.

Recent trials for hormonal male contraception are based on gestagens or GnRH antagonists combined with oral or injectable testosterone substitution. However, the efficacy of most trials remained disappointing. Norethisterone enanthate (NETE) has been used as a long-acting injectable female contraceptive and has shown sustained suppression of spermatogenesis in male monkeys and prolonged suppression of gonadotropins in men. This study was designed to prove the efficacy of the long-acting testosterone undecanoate ester (TU) alone or in combination with NETE in a phase II clinical trial. Fourteen healthy men received injections of 1000 mg TU in combination with injections of 200 mg NETE every 6 weeks over a period of 24 weeks, followed by a control period of 28 weeks. Another 14 volunteers received TU alone. During the study semen variables, reproductive hormones, clinical chemistry and lipid parameters, well-being, and sexual function were monitored. Scrotal content and prostates were checked sonographically. During the entire treatment period mean testosterone serum concentrations remained within the normal limits. Marked suppression of gonadotropins in both treatment groups resulted in azoospermia in 7 of 14 and 13 of 14 volunteers and in oligozoospermia in 7 of 14 and 1 of 14 in the groups given TU only or TU/NETE, respectively. However, the highest azoospermia rate in the TU/NETE group was achieved 8 weeks after the end of the treatment period, and 1 volunteer with very high initial sperm counts (mean, 190 million/mL at baseline) remained oligozoospermic (10.2 million/mL). From week 20 to week 24 there was a significant, fully reversible maximum weight gain of 3.7 kg, on the average, in the NETE group. In the NETE and TU alone groups there were significant 26.6% and 11.5% maximum decreases in high density lipoprotein cholesterol compared with baseline values during the treatment period. A significant elevation of low density lipoprotein and a decrease in lipoprotein(a) were detected in the TU/NETE group. In conclusion, combination treatment with NETE showed suppression of spermatogenesis comparable with results using testosterone esters in combination with GnRH antagonists or cyproterone acetate, but had more favorable injection intervals and better efficacy. Because of its long-lasting, profound suppression of spermatogenesis and the absence of serious side-effects, the combination of TU and NETE can be considered a first choice for further studies of hormonal male contraception.

Adult↗

PubMed1995

Hypothalamic multiunit activity and pulsatile luteinizing hormone release in the castrated male rat.

Using chronically implanted microelectrodes, multiunit electrical activity (MUA) was recorded from the arcuate nucleus of freely moving gonadectomized male rats. Intermittent increases in MUA activity (MUA volleys) closely associated with luteinizing hormone pulses measured in the peripheral circulation were observed, which confirms that this experimental approach can be used for monitoring the activity of the gonadotropin-releasing hormone-associated hypothalamic pulse generator in the male rat. The mean MUA volley frequency was 22.2 min (range 13-38 min), whereas the mean MUA volley duration was 2.7 +/- 0.8 min (standard deviation). In addition to a large inter-individual variability. MUA volley intervals also showed an important intra-individual variability. This observation suggests that, beside the mean frequency of pulse generator activation, the degree of variability in gonadotropin-releasing hormone-associated pulse generator activity might be an additional relevant parameter in the characterization of the reproductive function in the male rat.

Animals↗

PubMed2000

Reproductive state of rat mammary gland stroma modulates human breast cancer cell migration and invasion.

It has been established that the invasive behavior of cancer cells can be regulated by alterations in their extracellular environment. We investigated whether extracellular matrix isolated from nulliparous and postlactating (involuting) rat mammary glands differentially modulated the metastatic behavior of human breast cancer cells. Using modified Boyden chamber and three-dimensional culture assays, nulliparous mammary matrix was found to suppress motility and invasion in highly metastatic MDA-MB-435 cells, whereas involution mammary matrix supported motility and invasion in highly metastatic MDA-MB-435 cells, but not in cells with low metastatic potential. Biochemical characterization of the matrices revealed intact fibronectin (FN) and low matrix metalloproteinase activity in nulliparous mammary matrix and fragmented FN and high matrix metalloproteinase activity in the matrix isolated from involuting glands. Purified intact FN was found to inhibit cell invasiveness, whereas FN fragments enhanced cell invasiveness in a matrix metalloproteinase-dependent manner. These data suggest that physiological changes that occur in the mammary extracellular matrix as a result of reproductive status alter the in vitro parameters of metastatic potential.

Animals↗

PubMed1975

Estimation and computation of the growth rate in Leslie's and Lotka's population models.

Leslie's or Lotka's population model has a rate of natural increase (lambda or r) which represents the growth rate of the population and characterizes the ability of the population to attain a stable age distribution. In this article are presented upper and lower bounds on that rate, primarily in terms of the net reproduction rate and other commonly used parameters of the population. Also a discussion is given of quadratically convergent numerical iterative methods of computing the growth rate.

Age Factors↗

PubMedDate not supplied

[The interaction of the serotonin and dopaminergic systems of the brain in the mechanisms of latent inhibition in rats].

Decrease of serotonin concentration in the septo-hippocampal region of Wistar male rats was obtained by introduction of 5,7-dihydroxytryptamine in the raphe median nucleus. In seven days, after 20 pre-expositions of the conditioned stimulus (presentation of the experimental chamber) conditioned reaction of passive avoidance was elaborated. In sham-operated control the pre-exposition of the conditioned stimulus caused latent inhibition, determined by several parameters: low level of conditioned reaction reproduction, its prolonged preservation at the formed level and nonsubjection to amnesia. Introduction of haloperidol in a dose of 0.5 mg/kg one hour before learning restored the state of latent inhibition disturbed by switching off of the mesolimbic serotonin system. It is supposed that in the state of pre-exposition, the decrease of attention to nonreinforced stimulus takes place because of the intensification of inhibitory influence of the serotoninergic system and reciprocal decrease of dopaminergic system activity.

5,7-Dihydroxytryptamine↗

PubMed1988

[Psychological and psychosocial factors and relevant therapeutic measures in spontaneous abortion and recurrent spontaneous abortion and habitual abortion].

It has been demonstrated that psychological and psychosocial factors are implicated in spontaneous and recurrent spontaneous abortions. According to these results we showed in our review, that certain psychological disorders, such as anxiety and nervousness, psychosomatic and personality disorders, negative attitude towards sexuality and pregnancy, parental conflicts and others may impair pregnancy outcome. Severe psychological and psychiatric problems prior to pregnancy were rarely evidenced, in opposite, depressive reactions after pregnancy loss frequently observed. The results suggest possible interactions between etiologic and psychoreactive parameters. Relations between nervous system and reproductive organs may explain influences of stress upon pregnancy outcome, as elevated stress hormones (catecholamines, cortisol) are able to reduce fetal vascularisation and oxygen supply and possibly induce labour and abortion. These observations are of interest, because in a considerable number of cases cannot be found. Adequate counseling and therapeutics may help overcome depressive reactions after pregnancy loss and avoid further complications.

Abortion, Habitual↗

PubMed1980

[Experimental studies on various model material. 3. Dimensional behavior and reproductive fidelity as compared to those of elastomers].

Bandless impressions of tooth stumps obtained with the model materials Begolith, Dentaloc, Tewestone, Impredur and Keramid-Cement in combination with the elastic impression materials Silcoflex, Sanal/Silcoflex, Xirux/Xirux F and Impergum were studied in relation to dimensional behavior and reproduction fidelity. With reference to these parameters as well as to the hardness and abrasive behavior of the model materials after processing at various temperatures, recommendations are made for the optimum combination of these two groups of materials in practice.

Acrylic Resins↗

PubMed1996

Transmission of two pseudorabies virus strains that differ in virulence and virus excretion in groups of vaccinated pigs.

OBJECTIVE: To determine whether 2 pseudorabies virus (PRV) strains that differ in virulence differ in transmission among vaccine strain 783-inoculated pigs. DESIGN: Three experiments were conducted, each with 2 groups of 10 pigs inoculated with the glycoprotein E-negative vaccine 783. In the first 2 experiments, half of one group was inoculated with the mildly virulent strain Sterksel, and half of the other group was inoculated with the virulent strain NIA-3. The remaining pigs were contact-exposed to the inoculated pigs. In the third experiment, 2 pigs in each group were inoculated with strain NIA-3, and the other 8 pigs in each group were contact-exposed to these 2 pigs. ANIMALS: Specific-pathogen-free pigs that were sero-negative for antibodies to PRV. PROCEDURE: Estimation of the transmission of virus in each group was based on a stochastic model, in which the observable variable was the number of contact infections. The sole parameter of the model was the reproduction ratio theta. A glycoprotein E ELISA was used to determine whether infection occurred. Virus excretion in the oropharyngeal fluid was determined by plaque assay to measure infectivity. RESULTS: Vaccinated pigs had a significant difference in virus excretion between the mildly virulent and virulent strains. Sterksel strain-inoculated pigs shed significantly more virus than did NIA-3 strain-inoculated pigs. Despite this difference in virus excretion, the 2 strains did not differ in transmission. CONCLUSIONS: Both PRV strains would be eliminated from a population of vaccine strain 783-inoculated pigs.

Analysis of Variance↗

PubMed1996

A method for describing disease patterns during the life span of dairy cows.

This study presents some guidelines for describing the health status of dairy cows over their entire life span. It aims to define some types of health-paths (trajectories) described in terms of disease patterns (at the lactation level) and related to cow characteristics (breed, production potential) and farms. The data were collected over a 20-year period on three experimental farms. Eight diseases were analysed: clinical mastitis, lameness, placental retention, foot rot, digestive disorders, milk fever, metritis, and arthritis. The statistical procedures used were correspondence analysis of time-indexed tables and hierarchical ascending clustering. A total of 28 health-paths were identified and 16 of these (the most common) are described in detail. At the lactation level, eight disease patterns were defined: high incidence of disease other than mastitis (1), predominantly mastitis plus milk fever (2), predominantly foot rot (3), very low incidence of disease (4), mastitis plus digestive disorders (5), very high mastitis incidence (6), low incidence of disease (7), foot rot plus digestive disorders (8). Disease patterns 3 and 6 were more common in shorter life spans (< or = 4 lactations). Conversely, health profiles 2 and 4 were generally related to the longest life spans. These results will be included in a future model of the life span of dairy cows which will also take into account other performance parameters such as milk production and reproduction.

Aging↗

PubMed2002

Age-related changes in ovarian volume, antral follicle counts and basal FSH in women with normal reproductive health.

OBJECTIVE: To investigate the relation between ultrasound-based ovarian volume and antral follicle counts and hormonal parameters of ovarian reserve in a group of women with normal reproductive health. STUDY DESIGN: Prospective study. One hundred eight women with at least one previous pregnancy reaching term were divided into three age groups (group 1 = 35-39 years, group 2 = 40-44 years, and group 3 = 45-50 years). Basal hormone measurements and transvaginal ultrasonography estimation of ovarian volume and follicle counts were performed in the early follicular phase (day 3) of the menstrual cycle. RESULTS: There were significant differences in FSH (P < .0001) and E2 (P < .002) levels when group I was compared to groups II and III. There was a significant decrease in mean follicle counts (MFC) between groups I and III (P < .05). The decrease in mean ovarian volume (MOV) with age was not statistically significant. Age strongly correlated with MFC (r = -.38, P < .001) and weakly with MOV (r = -.29, P < .05). However, basal FSH correlated positively with age (r = .50, P < .001) and negatively with MOV (r = -.590, P < .001) and MFC (r = -.658, P < .001). Basal E2 correlated with MOV (r = .50, P < .001) and MFC (r = .50, P < .001). There was also a strong positive correlation between MFC and MOV (r = .777, P < .001). CONCLUSION: There was a decrease in MOV and MFC with aging coincident with increasing basal FSH levels after age 35 in women with normal reproductive health.

Adult↗

PubMed1994

DNA fingerprinting analysis of parent-offspring conflict in a bee.

Demonstrating the importance of haplodiploidy in the evolution of eusociality among the Hymenoptera (bees, wasps, and ants) requires estimation of four parameters: relatedness between cooperating individuals, effective mating frequency, sex ratio, and rates of worker reproduction. Multilocus DNA fingerprinting techniques permitted the precise determination of these parameters for the primitively eusocial bee Augochlorella striata (Halictidae). DNA fingerprints revealed an unprecedented resolution of genetic relationships within colonies, detecting factors such as intraspecific nest parasitism and diploid males that confounded estimates of relatedness and sex ratio, respectively. Parameter estimates (i) corroborate recent evidence for queen-worker conflict over the sex ratio and (ii) implicate the role of haplodiploidy in the evolution of worker behavior.

Animals↗

PubMed1995

[Biochemical aspects of the toxic effects of Supermethrin in a 140-day avian reproductive test].

Chronic toxic effects of supermethrin on some biochemical parameters (AST, ALT, LDH, creatinine and total proteins) were investigated in 84 individuals of Japanese quail divided into four groups (control-K, experimental group I-P1, experimental group II-P2, experimental group III-P3) in the conditions of 140-day avian reproductive test. The three experimental groups received the tested substance at these doses: P1-10.7 mg/kg l.w./day, P2-21.4 mg/kg l.w./day, P3-35.7 mg/kg l.w./day. The results of observation of the enzyme activities AST and ALT show that only the AST activity (in the course of 140-day avian reproductive test) significantly increased to 1.225 mu kat/l in the females of experimental group P1, to 1.053 mu kat/l in P2 and to 1.014 mu kat/l in P3 against the control, in which the AST activity was 0.670 mu kat/l. The values of AST activity in the males were 1.143 mu kat/l in P1, 1.117 mu kat/l in P2 and 1.090 mu kat/l in P3 against the control 0.8395 mu kat/l. The investigation of variations in total LDH activity in Japanese quail after 140-day avian reproductive test has shown an increase in the LDH activity in the males (11.193 mu kat/l in P1, 11.269 mu kat/l in P2, 8.245 mu kat/l in P3 and 7.362 mu kat/l in K) as well as in the females (10.91 mu kat/l in P1, 12.023 mu kat/l in P2, 10.196 mu kat/l in P3 and 7.055 mu kat/l in K).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1998

Predictive signs of discogenic lumbar pain on magnetic resonance imaging with discography correlation.

STUDY DESIGN: The correlation between discogenic lumbar pain and disc morphology was investigated by using magnetic resonance imaging and discography. OBJECTIVES: To assess the various pathologic parameters seen on magnetic resonance imaging in patients with discogenic lumbar pain and to correlate them with observations on discography. SUMMARY OF BACKGROUND DATA: Although numerous previous studies on the subject have been performed, the correlations between various pathologic findings on magnetic resonance imaging and pain reproduction by provoked discography have not been explained fully. METHODS: One hundred and one lumbar discs in 39 patients were studied with magnetic resonance imaging and pain provocation discography. When pain reproduction under discography was concordant, various pathologic parameters on magnetic resonance imaging were analyzed by three statistical parameters to determine the associated magnetic resonance imaging findings. RESULTS: Radial tears commonly are demonstrated on magnetic resonance imaging in discs with concordant pain on discography. The presence of these tears is not a reliable predictor of a painful disc on discography. Although a high-intensity zone on T2-weighted images is a relatively reliable predictor of pain, the statistical values were lower than those in previous studies. Massive degeneration and severe disc height loss were rare in this population. These findings were good predictors of pain on disc injection. CONCLUSIONS: Although the lumbar intervertebral discs with posterior combined anular tears are likely to produce pain, the validity of these signs for predicting discogenic lumbar pain is limited.

Adult↗

PubMedDate not supplied

Implications for clinical monitoring of intra-arterial blood pressure based on the frequency content of worst-case pressure waveforms.

There is no consensus regarding the minimum acceptable frequency response for a system intended for routine monitoring of invasive blood pressure in the operating rooms or intensive care units. Part of the problem stems from the diverse criteria used to validate faithful reproduction of the pressure waveform and waveform parameters. Another part of the problem is related to the site of pressure measurement: some anatomic sites have waveforms that are more difficult to reproduce than others. The most often quoted criteria, around which many clinical blood pressure monitoring systems have been constructed, are based on reproduction of all details of the pressure waveform from the most demanding anatomic sites. However, the routine clinical setting is primarily concerned with obtaining accurate values for systolic and diastolic blood pressures as recorded from peripheral arterial sites. This study was designed to obtain worst-case, in the sense of most difficult to measure, blood pressure waveforms from the femoral artery and the left ventricle using a canine model. The purpose of worst-case analysis was to create pressure waveforms that were at both extremes of frequency content, i.e., a rapidly beating heart with extraordinary contractility and a more slowly beating heart with little contractility. The premise of this type of analysis is that all naturally occurring pressure waveforms within a very broad physiologic range would fall within these extremes; therefore, the ability to measure the extreme waveforms would imply the ability to measure all those in between. Worst-case waveforms chosen from among 360 pressure waveforms were analyzed to determine the minimum frequency content of each waveform that would be required for faithful reproduction of systolic and diastolic pressures and the dP/dt. The criterion for faithful reproduction was chosen to be +/- 5% or 1 mmHg, whichever is greater. Data from the worst-case canine study, with supporting data collected intraoperatively from three patients, demonstrate that systolic and diastolic pressures can be obtained from a peripheral measurement site within 5%, requiring only two harmonics in conjunction with an appropriately low-pass-filtered catheter manometer system. Left ventricular pressure waveforms require five harmonics to reproduce the systolic and diastolic pressures within 5% or 1.0 mmHg, whichever is greater. Determination of the maximum dP/dt within +/- 5% from the worst-case peripheral and left ventricular waveforms required 20 and 22 harmonics, respectively.

Animals↗

PubMed2002

Hematology and clinical chemistry in dystocic and healthy post-reproductive female chameleons.

Prevalence of egg-laying disorders and hematology and blood chemical parameters were analyzed in free-ranging common chameleons (Chamaeleo chamaeleon) from southern Spain. During four reproductive seasons oviposition failures occurred only during dry years. Egg binding appeared to be an important cause of mortality. Oviductal eggs of dystocic females were longer and wider than those of females with normal oviposition. Blood cell counts, white blood cell differentials, hematocrit, and concentration of hemoglobin, total plasma protein, glucose, uric acid, aspartate aminotransferase, and creatinine phosphokinase in blood were determined for eight apparently healthy post-reproductive females and considered as reference values. These chameleons differed from other reptiles in high concentrations of glucose in blood, averaging 362 mg/dl, and in high numbers of heterophils. Females with dystocia differed from reference values in an increase in monocytes and in the high concentrations of aspartate aminotransferase probably associated with tissue trauma.

Animals↗

PubMed2004

Evolution of mutualism through spatial effects.

Mutualism among species is ubiquitous in natural ecosystems but its evolution is not well understood. We provided a simple lattice model to clarify the importance of spatial structure for the evolution of mutualism. We assumed reproductive rates of two species are modified through interaction between species and examine conditions where mutualists of both species, that give some benefit to the other species with their own cost, invade non-mutualists populations. When dispersal of offspring is unlimited, we verified the evolution of mutualism is impossible under any condition. On the other hand, when the dispersal is limited to neighboring lattice sites, mutualists can invade if the ratio of cost to benefit is low and the intrinsic reproductive rate is low in case where the parameter values are symmetric between species. Under the same conditions, non-mutualists cannot invade mutualist populations, that is, the latter are evolutionarily stable. In case of asymmetric parameters, mutualists tend to invade if the average value of costs to two species is low or that of benefits is high, and if the intrinsic reproductive rate is low for one of the two species. A mechanistic explanation of why mutualists increase when the dispersal is limited is given by showing that mutualist pairs of the two species at the same lattice site rapidly increase at the initial phase of the invasion.

Altruism↗

PubMed2000

Malaria transmission model for different levels of acquired immunity and temperature-dependent parameters (vector).

OBJECTIVE: Describe the overall transmission of malaria through a compartmental model, considering the human host and mosquito vector. METHODS: A mathematical model was developed based on the following parameters: human host immunity, assuming the existence of acquired immunity and immunological memory, which boosts the protective response upon reinfection; mosquito vector, taking into account that the average period of development from egg to adult mosquito and the extrinsic incubation period of parasites (transformation of infected but non-infectious mosquitoes into infectious mosquitoes) are dependent on the ambient temperature. RESULTS: The steady state equilibrium values obtained with the model allowed the calculation of the basic reproduction ratio in terms of the model's parameters. CONCLUSIONS: The model allowed the calculation of the basic reproduction ratio, one of the most important epidemiological variables.

Animals↗