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PubMed2004

Platelet-activating factor receptor deficiency delays elimination of adult worms but reduces fecundity in Strongyloides venezuelensis-infected mice.

We describe the parasitological kinetics and histopathological and immunological alterations in platelet-activating factor receptor-deficient (PAFR(-/-)) and wild-type mice after a single Strongyloides venezuelensis infection (subcutaneous inoculation of 500 L3 larvae). There was no difference in the numbers of worms that reached and became established in the small intestines of PAFR(-/-) and wild-type mice. However, at 12 days after infection, significantly more worms were recovered from PAFR(-/-) mice. Although PAFR(-/-) infected mice showed a delay in elimination of adult worms, worms established in the small intestine of these mice produced a significantly lower number of eggs due to a reduction in worm fecundity. There were also significant reductions in the number of circulating and tissue eosinophils and tumor necrosis factor levels in the small intestines of PAFR(-/-) mice infected for 7 days compared to the number and level in wild-type mice. Histological analysis confirmed the reduced inflammatory process and revealed that the PAFR(-/-) mice had a smaller number of goblet cells. The concentrations of the type 2 cytokines interleukin-4 (IL-4), IL-5, and IL-10 were lower in small intestine homogenates and in supernatants of antigen-stimulated lymphocytes from spleens or mesenteric lymph nodes of PAFR(-/-) mice than in the corresponding preparations from wild-type mice. Thus, in S. venezuelensis-infected PAFR(-/-) mice, decreased intestinal inflammation is associated with enhanced worm survival but decreased fecundity. We suggest that although a Th2-predominant inflammatory response decreases worm survival, the worm may use factors produced during this response to facilitate egg output and reproduction. PAFR-mediated responses appear to modulate these host-derived signals that are important for worm fecundity.

Animals↗
PubMed2004

Miscarriage but not fecundity is associated with progression of joint destruction in rheumatoid arthritis.

OBJECTIVE: To determine whether reproductive history before disease onset is associated with severity of joint destruction in rheumatoid arthritis. METHODS: A special early arthritis clinic (EAC) was established at the department of rheumatology of Leiden University Medical Centre. General practitioners were encouraged to refer patients with joint complaints to this clinic, where the diagnosis of rheumatoid arthritis was made by a rheumatologist. In all, 113 female patients with definite rheumatoid arthritis were included in this study. A structured questionnaire was administered and joint damage was assessed by sequential x rays of the hands and feet, using the modified Sharp score. RESULTS: The length of time of unprotected intercourse until first pregnancy (fecundity) was comparable with data from earlier studies, with 16% of the patients reporting a time to first pregnancy of more than 12 months. Fecundity did not reflect the extent of joint damage over time. The miscarriage rate was 15% per pregnancy, comparable to population figures (12-15%). A significant increase in joint damage over a two year follow up was found in patients with rheumatoid arthritis who had experienced at least one miscarriage compared with those who had never had a miscarriage (mean modified Sharp scores at 2 years, 24 (95% confidence interval, 15 to 32) and 16 (10 to 23), respectively; p<0.05). At baseline, the Sharp scores were similar in the two subgroups. CONCLUSIONS: Miscarriage before disease onset but not fecundity is associated with the progression of joint damage in rheumatoid arthritis.

Abortion, Spontaneous↗
PubMed1993

Fat and female fecundity: prospective study of effect of body fat distribution on conception rates.

OBJECTIVES: To study the effect of body fat distribution in women of reproductive age on fecundity. DESIGN: Prospective cohort study of all women who had entered a donor insemination programme. SETTING: One fertility clinic serving a large part of the midwest of the Netherlands. SUBJECTS: Of 542 women attending the clinic for artificial insemination for the first time, 500 women were eligible for study. MAIN OUTCOME MEASURES: Probability of conception per cycle and number of insemination cycles before pregnancy or stopping treatment. RESULTS: A 0.1 unit increase in waist-hip ratio led to a 30% decrease in probability of conception per cycle (hazard ratio 0.706; 95% confidence interval 0.562 to 0.887) after adjustment for age, fatness, reasons for artificial insemination, cycle length and regularity, smoking, and parity. Increasing age was significantly related to lower fecundity (p < 0.05); very lean and obese women were less likely to conceive (p < 0.10) as were women with subfertile partners (p < 0.10). All other exposure variables were not significantly related to fecundity. CONCLUSIONS: Increasing waist-hip ratio is negatively associated with the probability of conception per cycle, before and after adjustment for confounding factors. Body fat distribution in women of reproductive age seems to have more impact on fertility than age or obesity.

Adipose Tissue↗
PubMed2002

Host plant quality and fecundity in herbivorous insects.

Host plant quality is a key determinant of the fecundity of herbivorous insects. Components of host plant quality (such as carbon, nitrogen, and defensive metabolites) directly affect potential and achieved herbivore fecundity. The responses of insect herbivores to changes in host plant quality vary within and between feeding guilds. Host plant quality also affects insect reproductive strategies: Egg size and quality, the allocation of resources to eggs, and the choice of oviposition sites may all be influenced by plant quality, as may egg or embryo resorption on poor-quality hosts. Many insect herbivores change the quality of their host plants, affecting both inter- and intraspecific interactions. Higher-trophic level interactions, such as the performance of predators and parasitoids, may also be affected by host plant quality. We conclude that host plant quality affects the fecundity of herbivorous insects at both the individual and the population scale.

Animals↗
PubMed1989

Hypergravity and ageing in Drosophila melanogaster. 1. Fecundity.

In Drosophila melanogaster daily fecundity has been recorded throughout life of flies kept at various gravity levels (1-5 g). Hypergravity (HG) did not decrease total fecundity but modified its expression during life. The 1 g group could be opposed to the various HG groups, i.e. a clear regression of the various fecundity items on the HG level could not be disclosed. Results are discussed in relation with Pearl's rate of living theory.

Aging↗
PubMed1994

Cycle fecundity in baboons of proven fertility with minimal endometriosis.

To the best of our knowledge this is the first prospective study in nonhuman primates of proven fertility in the wild, which compares fertility between animals with spontaneous minimal endometriosis and those with a normal pelvis. During 7 months 13 female baboons were exposed to males and all pregnancies were terminated by hysterotomy. A diagnostic laparoscopy was performed to assess the presence of pelvic endometriosis at the end of the fertility trial. Sixty-one percent of the baboons became pregnant at least once and the cycle fecundity was 21%. No obvious difference was found between baboons with (n = 7) and without endometriosis (n = 6) in either pregnancy rate (57 and 67%, respectively) or cycle fecundity (18 and 24%, respectively). These data suggest that in baboons with spontaneous minimal endometriosis the cycle fecundity is not grossly reduced.

Animals↗
PubMed2001

Is an elevation in basal follicle-stimulating hormone levels in unexplained infertility predictive of fecundity regardless of age?

An elevation in follicle-stimulating hormone (FSH) levels is considered to reflect lowered ovarian function, resulting in poor fecundity in infertile women. However, it remains to be clarified whether or not the significance of FSH levels applies equally to all women irrespective of age. The objective of the present study is to compare basal FSH levels in infertile women who conceived or not after stratification by age. A total of 144 infertile women between ages 25 and 45 who underwent infertility treatment due to unexplained infertility in the University of Tokyo Hospital were included in the retrospective study. Subjects were divided by age into two groups, < 38 (n=98) vs > or = 38 (n=46) years, with ages ranging from 25 to 37, and from 38 to 45, respectively. Blood samples were collected in early follicular phase (day 4-6) for assessment of basal levels of LH, FSH, and PRL. In the older group, pregnant cases had significantly lower FSH levels (6.07 +/- 2.83 mIU/ml) than nonpregnant cases (9.60 +/- 3.67 mIU/ml), whereas no difference in basal FSH levels was observed between pregnant and nonpregnant cases in the younger group. Basal FSH levels of pregnant cases in the older group were significantly lower than those of pregnant cases in the younger group (8.26 +/- 2.95 mIU/ml). Basal LH and PRL levels were not related to fecundity in either group. Thus, an increase in basal FSH levels as a predictor of fecundity should be considered in the context of age.

Adult↗
PubMed2004

Comparative study of the fecundity and fertility of Biomphalaria glabrata (Say, 1818) and Biomphalaria straminea (Dunker, 1848) in a laboratory through self-fertilization and cross-fertilization.

The aim of this study was to compare the fecundity and fertility of B. glabrata and B. straminea by cross- and self-fertilization. To attain this objective, laboratory-raised strains of B. glabrata and B. straminea were used. The former originated from natural breeding grounds in the municipality Paulista, state of Pernambuco, Brazil. The latter originated from irrigation ditches in the municipality of Petrolândia, in the same state. Snail populations of B. glabrata and B. straminea were maintained for 240 days in laboratory. Their fecundity was evaluated by noting the number of egg-masses, eggs and eggs per mass. Their fertility was evaluated by the number of viable eggs and the hatching rate. B. straminea was markedly more fecund than B. glabrata through cross- and self-fertilization, namely: greater egg-mass; higher egg production and more eggs per mass. Regarding fertility, there seemed to be no preferential period for occlusion to occur or a trend in the rhythm of producing viable eggs.

Animals↗
PubMed2001

Fecundity of Hoplopleura scapteromydis (Phthiraptera: Anoplura, Hoplopleuridae), ectoparasite of Scapteromys aquaticus (Rodentia: Muridae) in Rio de La Plata marshlands, Argentina.

Density and age structure of lice collected from captured Scapteromys aquaticus rodents were studied to estimate the fecundity of Hoplopleura scapteromydis. The number of eggs with a visible embryo inside (E), nymphs (N), adult males (AM), and adult females (AF) were recorded for each rodent. For the ith rodent, the fecundity of H. scapteromydis, F(i), was estimated as F(i) = [[E(i) + N(i)]/2]/AF(i)/T, where T represents the period of preimaginal development (unknown and arbitrarily considered as T = 1), and the sex ratio of the preimaginal stages was supposed to be 1:1. In order to look for density-dependent effects, F(i) was plotted against AM(i), this being an independent estimation of infrapopulation density. The number of rodents suitable for AF and AM calculations was 38 (57% of the parasitized animals). Almost 95% had a low-to-moderate louse burden (1 < AM < 30) and were captured every season, whereas only 3% had a heavy (61 < AM < 70, captured in winter) or very heavy (AM > 80, captured in summer) louse burden. The extreme values of F were 0.63 and 18 (1.3 and 36 if both sexes were considered). High-to-moderate F-values (F > 5) were estimated in only 5 rodents that exhibited low louse density, whereas low F-values (F < 5) were found at all louse densities. Notwithstanding the tendency toward an inverse relationship between fecundity and infrapopulation density, the correlation was not significantly different from 0.

Animals↗
PubMed1987

Lack of demonstrable density-dependent fecundity of schistosomiasis mansoni: analyses of Egyptian quantitative human autopsies.

Conflicting interpretations regarding the fecundity of schistosomes infecting human beings have arisen and are, in part, due to the inability to directly measure the parameters. The inability to experimentally manipulate human beings necessitates the use of surrogate variables, i.e., number of eggs per gram of feces, as an indicator of worm burden. This study reanalyzes data from quantitative autopsies performed in Egypt by Cheever and colleagues on individuals with active Schistosoma mansoni infections. Exploratory regression analysis of the relationship of female worms recovered to eggs/g of feces and of female worms to eggs retained in host tissues suggests a linear relationship in both cases. Over the observed range of female worms recovered from an individual human being, the estimated worm fecundity, as measured by the number of eggs either in feces or retained in tissues per female worm, is not significantly different from a constant value. Hence, density-dependent fecundity of S. mansoni in the human host, as suggested by others, is not demonstrated in these data.

Adolescent↗
PubMed2002

Mother's age and daughter's fecundity. An epidemiological analysis of late 19th to early 20th century family reconstitutions.

BACKGROUND: At both ends of the female reproductive span, the risk of reproductive problems is increased. We hypothesize that this is partly explained by inadequate maturation of oocytes ('pre-ovulatory overripeness'). As this phenomenon has been shown to lead to gonadal anomalies in the offspring of animals, we tested the prediction that daughters of older and very young mothers more often suffer reproductive problems due to ovarian maldevelopment. METHODS: We analysed family reconstitutions of 1907 women born in Rotterdam, the Netherlands, between 1873 and 1902. We defined several measures of fecundity based on numbers, birth rates and fates of offspring. We made use of general estimating equations (GEE), a statistical technique that allowed simultaneous analysis of different births per woman while controlling for various time-dependent or time-independent co-variables. RESULTS: The results indicated an increased risk of childlessness (adjusted odds ratio (aOR = 2.6, 95% CI : 1.1-7.4), stillbirth (aOR = 2.5, 95% CI : 1.1-5.6) and multiple birth (aOR = 2.1, 95% CI : 0.8-5.4) for daughters of mothers of >or=40 years as compared to daughters born to mothers of intermediate age (24-30 years). Daughters of mothers of <or=20 years, on the other hand, did not appear to have reduced fecundity. CONCLUSION: The results point to a decreased fecundity of daughters of older mothers, but not of daughters of younger mothers. The inconsistency of the results with respect to the oocytal-maturation hypothesis points to the action of other causal or non-causal mechanisms.

Adolescent↗
PubMed2002

Cycle fecundity in controlled ovarian hyperstimulation and intrauterine insemination. Influence of the number of mature follicles at hCG administration.

OBJECTIVE: To determine if cycle fecundity in controlled ovarian hyperstimulation (COH) with intrauterine insemination (IUI) cycles is influenced by the number of mature follicles at the time of hCG administration. STUDY DESIGN: Retrospective data analysis of 75 infertility patients undergoing 164 consecutive COH/IUI cycles with FSH and/or hMG in a university-affiliated private infertility center. Cycles were compared for number of mature follicles (> or = 15 mm) and peak serum estradiol levels, total number of ampules and days of gonadotropin use, and clinical pregnancy rate. RESULTS: There was a statistically significant increase in cycle fecundity when three to four mature follicles were stimulated. Peak estradiol levels were significantly different in the groups, as predicted from the number of follicles. The groups were not statistically different in age or etiology of infertility. Group A (1-2 mature follicles) required significantly more FSH/hMG than group B (3-4 follicles) or group C (> or = 5 follicles). CONCLUSION: In COH/IUI cycles, three to four mature follicles yield improved cycle fecundity as compared to that in cycles with a smaller or larger number of follicles. These findings may help identify patients who will be more successful in conceiving with COH/IUI versus those who should be counseled to use other assisted reproductive technologies.

Adult↗
PubMed1975

[Fecundity and embryonal mortality of four inbred strains of mice, BALB/c, B10.CW, A/Sn, CC57W and their hybrids].

The object of this investigation was the potential fecundity of four inbred strains of mice, viz. BALB/c, B10.SW, CC57W, A/Sn and of their different hybrid combinations. The inbred strains studied had different normal ovulation numbers varying from 9,2 to 11,9 and different death-rate of embryos before (10,99-39,49%) and after (9,05-22,47%) the implantation. The numbers of live embryos per female in the strains A/Sn, B10.CW and CC57W were practically equal to one another, but significantly larger than in the strain BALB/c. Interlinear crosses resulted in a considerable decrease of the total embryonic death-rate, while the normal ovulation number did not undergo any changes. The number of live embryos in simple hybrids did not differ significantly from that in the maternal inbred strains. Therefore the heterozygosity of embryos did not affect significantly the potential fecundity of females. The number of surviving embryos per female increased in the cross between the simple hybrids (BALB/cXB10.CW) X (CC57WXA/Sn) to 8,9 +/- 0,37. This heterosis was the result of the total death-rate of embryos down to 14,89%. As it is shown by the comparison of the potential fecundity of pregnant females carrying homo- and heterozygous embryos to that of pregnant hybrid females, the rate of survival of embryos depends more on the genotype of the mother, than on that of the embryos.

Animals↗
PubMed1975

[Fecundity and embryonal mortality of four inbred mouse lines, BALB/c, B10.CW, A/Sn, CC57W and their hybrids].

The object of this investigation was the potential fecundity of four inbred strains of mice, viz. BALB/c, B10.SW, CC57W, A/Sn and of their different hybrid combinations. The inbred strains studied had different normal ovulation numbers varying from 9,2 to 11,9 and different death-rate of embryos before (10,99-39,49%) and after A/Sn, B10.CW and CC57W were practically equal to one another, but significantly larger than in the strain BALB/c. Interlinear crosses resulted in a considerable decrease of the total embryonic death rate, while the normal ovulation number did not undergo any changes. The number of live embryos in simple hybrids did not differ significantly from that in the maternal inbred strains. Therefore the heterozygosity of embryos did not affect significantly the potential fecundity of females. The number of surviving embryos per female increased in the cross between the simple hybrids (BALB/cXB10.CW)X(CC57WXA/Sn) to 8.9 +/- 0,37. This heterosis was the result of the total death-rate of embryos down to 14,89%. As it is shown by the comparison of the potential fecundity of pregnant females carrying homo- and heterozygous embryos to that of pregnant hybrid females, the rate of survival of embryos depends more on the genotype of the mother, than on that of the embryos.

Animals↗
PubMedDate not supplied

[The regularities in connection between fecundity with body weight and growth rate in fishes].

The absolute and relative fecundity of freshwater, anadromous and marine fishes (102 species and subspecies from 33 families) and its dependence on body mass and growth rate were analyzed on the basis of published data. According to the spawning type all studied fishes were divided into species with short-term and single spawning and fishes with extended or long-term spawning. The equations of dependence of absolute fecundity (E) on body mass (W) were calculated: E = 1.033 W0.578 (the first group) and E = 0.792 W0.74 (the second group). If W < 177 g the equations don't differ significantly and one may use the equation E = 1.34(-0.742) for both groups. The body mass of females at age of maturity expressed as a portion of maximal definitive body mass equals 0.22 +/- 0.044 for many different species with 0.95 probability. The relative fecundity (a1) of some species negatively correlates with maximal body mass of adult individuals (Wmax). This dependence is expressed by equations: a1 = 3.033 Wmax-0.549 (for the first group) and a1 = 1.726 Wmax-0.351 (for the second group). Value of ratio Wov/W of different fish species changes irregularly from 0.054 to 0.32 and its average is 0.150 +/- 0.012 for the first group and 0.156 +/- 0.007 for the second one. In such a way, single reproduction effort of fishes is approximately 0.15. Comparison of data on Pisces, Crustacea, Amphibia, Reptilia, and Mammalia revealed that reproduction effort of different aquatic and terrestrial invertebrates and vertebrates varies within rather narrow limits (from 0.05 to 0.44). Average values of this index varies even less--from 0.097 to 0.238, on average 0.162, i.e. approximately 15-18% of animals' body mass falls on their reproduction constituent.

Animals↗
PubMed2003

[Studies of BMPR-IB and BMP15 as candidate genes for fecundity in little tailed han sheep].

BMPR-IB gene which controls the fecundity of Booroola Merino and BMP15 gene which affects the ovulation of Invedale and Hanna were studied as candidate genes on the fecundity of Little Tailed Han Sheep, and their mutations and genetic effects were analyzed. The results showed that there was a same mutation in BMPR-IB gene (A746G) of Little Tailed Han Sheep as that of Booroola Merino. The BB mutation genotype was superior in prolific Little Tailed Han Sheep, and the ewes with genotype BB had 0.97(P < 0.05) and 1.5(P < 0.01) lambs more than those with genotype + + in the first parity and later parities, respectively. It could be inferred that BMPR-IB gene was related with the major gene that controls the high prolificacy of Little Tailed Han Sheep. While there was not mutation of V31D or Q23Ter in BMP15 gene of Little Tailed Han Sheep, it showed that the fecundity mechanism of Little Tailed Han Sheep was different from that of Romney sheep. Then it was ruled out the possibility that the ovulation of Little Tailed Han Sheep was affected by the mutation of BMP15 gene.

Alleles↗
PubMed1991

[Biology of Triatoma infestans populations: fluctuations of fecundity and mortality].

Fecundity and mortality in population of insects is relevant to the epidemiology of insect transmitted diseases. These variables were studied for T. infestans during 5 years under constant conditions of temperature, relative humidity, light periods and individual density. Mean fecundity was 0.96 +/- 0.69 eggs/female-week, range 0 to 4. Minima were observed in april and maxima in october and november. Mean mortality of intermediate forms was 0.058 +/- 0.031/individual-week, range 0.009 to 0.135, similar for females and males. Minima for mortality were observed in june and july, maxima from november to march. Fluctuations of fecundity are attributed to endogenous cyclic changes related to mating and egg laying. Possible explanations for fluctuations in mortality include the action of infectious agents. The secondary mortality cycle may be related to delayed effect of population density or to differential mortality of cohorts born under different environmental conditions.

Animals↗
PubMed1991

Fecundity of gastrointestinal trichostrongylid nematodes of sheep in the field.

Twenty-two Dorset Rambouillet lambs were moved to contaminated pasture on Apr 1, 1987. At regular intervals thereafter, pairs of lambs were withdrawn and euthanatized. Gastrointestinal parasites in the abomasum, small intestine, cecum, and large intestine were removed and counted. The last pair of lambs was euthanatized 8 months after original placement on the contaminated pasture. Fecal samples were taken at 3- to 4-week intervals throughout the grazing season and the fecal egg counts were used to estimate parasite fecundity (output of eggs per female parasite per day). The principal parasite genera found included Haemonchus spp, Trichostrongylus spp, and Nematodirus spp. In each of the genera examined, parasite fecundity remained the same irrespective of the intensity or duration of infection. Estimated average fecundities (eggs/female/day) were as follows: Haemonchus contortus, 6,582; Trichostrongylus spp, 262; Nematodirus spp, 40; and Oesophagostomum venulosum, 11,098.

Abomasum↗