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PubMed2005

Fecundity and pregnancy outcome in a cohort with sickle cell-haemoglobin C disease followed from birth.

OBJECTIVE: To compare pregnancy outcome in sickle cell-haemoglobin C (SC) disease with that in homozygous sickle cell (SS) disease and age-matched controls with a normal haemoglobin (AA) genotype. DESIGN: A cohort study followed from birth. SETTING: Sickle Cell Clinic, University Hospital and other Jamaican hospitals. POPULATION: Ninety-five pregnancies in 43 patients with SC disease, 94 pregnancies in 52 patients with SS disease and 157 pregnancies in 68 controls. METHODS: Systematic review of all pregnancies occurring in sample population. Kaplan-Meier analysis for interval to first pregnancy, and the t test, chi2 test or Fisher's exact test as appropriate; correction was made for multiple testing and multiple linear regression was used for analysis of determinants of birthweight. MAIN OUTCOME MEASURES: Age at menarche, interval to first pregnancy, outcome of pregnancy, maternal complications and possible predictors of low birthweight. RESULTS: Menarche was marginally delayed in SC disease compared with AA controls (median age 13.7 vs 13.0 years, P= 0.02) but age at first pregnancy was similar (median age 22.5 vs 20.1 years, P= 0.32). Pregnancy outcome in SC disease did not differ from AA controls but compared with SS disease there were marginally fewer miscarriages, more live deliveries and greater birthweight. The prevalence of pregnancy-induced hypertension, pre-eclampsia, antepartum or postpartum haemorrhage in SC disease did not differ from AA controls but the prevalence of sickle-related complications was similar to SS disease. CONCLUSIONS: Contrary to some claims, pregnancy outcome in SC disease is generally benign compared with SS disease.

Adolescent↗
PubMed1998

Do autoantibodies to sperm reduce fecundity? A mini-review in historical perspective.

PROBLEM: The paradox that early studies of antisperm antibodies in men showed a strong correlation between titers of circulating antibodies (essentially immunoglobulin [Ig] G) and reduction in conception rates, whereas more recent studies have indicated that the antifertility effect is mainly (or exclusively?) associated with IgA antibodies, impairing sperm migration through cervical mucus, was studied. METHOD OF STUDY: Relevant literature focusing on antibodies on ejaculated sperm was analyzed. RESULTS: Direct mixed antiglobulin reaction (MAR) and immunobead-binding tests are excellent and sensitive techniques for demonstrating antibodies of the IgG and IgA classes on sperm, and they have revealed that IgA antibodies are, with very rare exceptions, found only when IgG antibodies are also present. However, these tests tell little about the amounts of antibodies present, and attempts to measure quantitatively the amounts of Ig on sperm have indicated higher levels of IgA than IgG (despite the strongest MAR reactivities for IgG). CONCLUSIONS: The patients with high levels of IgA to their sperm are mainly men with strong immune responses and, therefore, also high antibody titers in serum. Apparently, the locally produced IgA antibodies reach the sperm and occupy the binding sites before the main bulk of IgG reaches the seminal compartment with the prostatic fluid.

Autoantibodies↗
PubMed2004

Growth, fecundity and competitive ability of transgenic Trifolium subterraneum subsp. subterraneum cv. Leura expressing a sunflower seed albumin gene.

Ecological risk assessment is an important step in the production and commercialisation of transgenic plants. To date, however, most risk assessment studies have been performed on crop plants, and few have considered the ecological consequences associated with genetic modification of pasture species. In this study we compared the growth, yield, population dynamics and competitive ability of transgenic Trifolium subterraneum subsp. subterraneum cv. Leura (subclover) expressing a nutritive sunflower seed albumin (ssa) gene with the equivalent non-transgenic commercial line in a glasshouse competition trial. Plants were grown in low-fertility soil typical of unimproved native southeastern Australian grasslands. We measured survivorship, seed production rate, seed germination rate, seed weight, dry weight yield and the intrinsic rate of population increase (lambda) of plants grown in mixtures and monocultures over a range of densities (250 to 2000 plants m(-2)), and also determined intragenotypic and intergenotypic competition coefficients for each line. There were no significant differences between transgenic and non-transgenic plants in any of the measured variables except survivorship; transgenic plants had a significantly lower survival rate than non-transgenic plants when grown at high densities (p<0.01). However, density-dependent effects were observed for all measured variables, and in all models plant density affected the response variables more than the presence of the transgene. Based on these results, we conclude that the ssa gene construct appears to confer no advantage to transgenic T. s. subterraneum cv. Leura growing in mixed or pure swards under the fertility and density regimes examined in the trial. Our data also suggest that transgenic subterranean clover expressing the ssa gene is unlikely to exhibit a competitive advantage over associated non-transgenic commercial cultivars when grown in dense swards in low-fertility pastures.

Albumins↗
PubMed1975

Effects of electromagnetic fields on fecundity in the chicken.

Egg production was reduced when young laying hens were kept in contact with metal cages while being continuously exposed to the following cw fields: a vhf field at a frequency of 260 MHz, with an incident power that decreased from 100 to 4mW during the experiment; a uhf field at a frequency of 915 MHz, with an incident power of 800 mW during the first 2.5 weeks, zero during the following week, and 200 mW for the remainder of the experiment; a uhf field at 2.435 GHz, with an incident power of 800 mW; an elf electric field at a frequency of 60 Hz, with a calculated value of field strength of 1600 V/m; an elf magnetic field at 60 Hz, with a value of magnetic flux density of 1.4G. With the exception of the hens exposed to the uhf field at 915 MHz, all other treated groups laid significantly less eggs than the controls (p smaller than or equal to 0.01). This reduction (similar 15% less than the controls) began with the first 4-week production period. The egg production curves for the hens exposed to the vhf field at 260 MHz and to the uhf field at 2.435 GHz were approximately the same beginning with the sixth week of production, and they maintained comparable production levels for the remainder of the experiment. An 8% total drop in production also was experienced in the group of birds exposed to the 915-MHz field, which pulsed because of equipment failure. Egg production rate curves for the birds in the elf electric and magnetic fields were substantially different from those exhibited by birds in the other electromagnetic fields. The birds in the E-field regained a production level comparable to the controls after 11 weeks production, whereas those in the B-field dropped to 31% production, which was approximately 40% poorer than the controls by the twelfth week of production. Fertility of cocks and hens was not affected by continuous low-power vhf and uhf near-zone electromagnetic exposure or elf electric or magnetic field treatment. Fertility was exceptionally good, except for the controls and the hens exposed to the elf electric field. The hatchs of fertile and of total eggs were not significantly influenced by exposure to any of the five fields. A considerably lower incidence of male chicks was noted in the elf magnetic field treatment (32.3%). The sex ratio in the other groups appeared to be relatively normal. No macroscopic abnormalities attributable to treatments were noted in the chicks hatched or in the dead embryos.

Animals↗
PubMed1988

Fecundability.

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Adolescent↗
PubMed1976

Fecundity and proglottid release of Taenia ovis and T. hydatigena.

The rate of release of proglottids was examined in 19 dogs infected with Taenia ovis and 16 infected with T. hydatigena. Faeces were examined for proglottids daily until the apparent death of the worms. Autopsies were then performed and surviving worms recovered. The number of eggs per proglottid was estimated in 12 T. ovis and 12 T. hydatigena from natural infections. In dogs infected with T ovis the time of first recovery of proglottids after infection varied from 44 days to more than 126 days. Up to 3 proglottids per worm per day might be released, each containing about 88,000 eggs. Infection can persist longer than 5 years. Dogs infected with T. hydatigena released their first proglottid from 48 to 65 days after infection. Each worm could produce 2 proglottids per day, each containing about 53,000 eggs. Although each T. ovis may produce over 250,000 and each T hydatigena over 100,000 eggs per day, it is probable that many of them hatch in the small intestine and are rendered inactive.

Animals↗
PubMed1992

The survival and fecundity of buffalo flies after treatment of cattle with three anthelmintics.

Two anthelmintics with known insecticidal action (ivermectin and closantel) and one with no recorded effect on insects (levamisole) were tested to evaluate their effects on buffalo fly (Haematobia irritans exigua). Blood from animals given closantel or levamisole had no significant effect on mortality of buffalo flies in an in-vitro assay. In contrast, blood from animals given ivermectin showed a dose-dependent effect on the mortality of buffalo flies. At 24 h after one injection of the recommended dose of ivermectin, 98% of the flies applied to cattle in an in-vivo assay are killed. Blood from cattle injected with ivermectin killed 95% of flies 8 d after injection and still killed 15% of flies at 18 days after injection. Surviving flies laid almost no eggs and this effect on flies was significant up to 33 d after injection. The results indicate that ivermectin may be useful to control buffalo fly populations in the field.

Animals↗
PubMed2001

Rising CO2 levels and the fecundity of forest trees.

We determined the reproductive response of 19-year-old loblolly pine (Pinus taeda) to 4 years of carbon dioxide (CO2) enrichment (ambient concentration plus 200 microliters per liter) in an intact forest. After 3 years of CO2 fumigation, trees were twice as likely to be reproductively mature and produced three times as many cones and seeds as trees at ambient CO2 concentration. A disproportionate carbon allocation to reproduction under CO2 enrichment results in trees reaching maturity sooner and at a smaller size. This reproductive response to future increases in atmospheric CO2 concentration is expected to change loblolly dispersal and recruitment patterns.

Atmosphere↗
PubMed2001

Fecundity-survival trade-offs and parental risk-taking in birds.

Life history theory predicts that parents should value their own survival over that of their offspring in species with a higher probability of adult survival and fewer offspring. We report that Southern Hemisphere birds have higher adult survival and smaller clutch sizes than Northern Hemisphere birds. We subsequently manipulated predation risk to adults versus offspring in 10 species that were paired between North and South America on the basis of phylogeny and ecology. As predicted, southern parents responded more strongly to reduce mortality risk to themselves even at a cost to their offspring, whereas northern parents responded more strongly to reduce risk to their offspring even at greater risk to themselves.

Animals↗
PubMed1979

Prenatal stress reduces fertility and fecundity in female offspring.

Female rats subjected to prenatal stress later experienced fewer conceptions, more spontaneous abortions and vaginal hemorrhaging, longer pregnancies, and fewer viable young than nonstressed rats. The offspring of the prenatally stressed rats were lighter in weight and less likely to survive the neonatal period. Prenatal stress may influence the balance of adrenal and gonadal hormones during a critical stage of fetal hypothalamic differentiation, thereby producing a variety of reproductive dysfunctions in adulthood.

Animals↗
PubMed1971

Fecundity.

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Contraception↗
PubMed1988

Effects on the fecundity of sheep of immunisation against androstenedione.

Fecundin, which actively immunises sheep against androstenedione, has now been commercially available to British farmers for three seasons. By its use an average increase of 20 to 25 per cent in the number of lambs reared can be expected, although the results on individual farms have been variable. During 1984-85 and 1985-86 ADAS carried out trials involving over 2000 ewes on 13 commercial farms. The responses to the treatment were statistically significant in both years (+23 per cent in 1984-85 and +27 per cent in 1985-86). However, the ranges in response were from -2 per cent to +49 per cent and +9 per cent to +42 per cent in 1984-85 and 1985-86, respectively. Similar results have been reported by other workers and commercial farmers using the technique. From these data it is clear that there are interactions between the treatment and animal factors including breed, body condition, nutrition, season and management. These factors are discussed with regard to the implications for the use of the product in commercial flocks.

Androstenedione↗
PubMed1980

Correlations between chromosome segments and fitness in Drosophila melanogaster. IV. Fecundity, viability and the third chromosome.

Unmarked segments within the third chromosome of three different Drosophila melanogaster lines were assessed for their effects on egg production and egg viability. By making a series of crosses among original and derived recombinant lines, it was possible to estimate parameters representing additive, dominance (for egg production), and interaction effects of the segments. Each segment influences both traits, but to extend which are dependent on the genetic background provided by an adjacent segment. There is no clear pattern, however, with respect to the segments' joint effects on the two characters. Unlike in the previous study involving the X chromosome, the majority of the derived recombinant lines were superior in fitness to their original lines. The agricultural implications of this result with respect to the manipulation of chromosomal segments in order to achieve higher yields are discussed.

Animals↗