Search results for "Fertility"
showing 10 items of 629 documents
Variable male potential rate of reproduction: high male mating capacity as an adaptation to parasite–induced excess of females?
2003
Numerous animals are known to harbour intracytoplasmic symbionts that gain transmission to a new host generation via female eggs and not male sperm. Bacteria of the genus Wolbachia are a typical example. They infect a large range of arthropod species and manipulate host reproduction in several ways. In terrestrial isopods (woodlice), Wolbachia are responsible for converting males into females (feminization (F)) in some species, or for infertility in certain host crosses in other species (cytoplasmic incompatibility (CI)). Wolbachia with the F phenotype impose a strong excess of females on their host populations, while Wolbachia expressing CI do not. Here, we test the possibility that male m…
Does the sex of firstborn children influence subsequent fertility behavior? evidence from family reconstitution.
2006
According to recent studies in evolutionary anthropology, firstborn daughters influence both parity progression and sibling survival by acting as so-called helpers at the nest. Based on 534 sets of household data from family reconstitution, the current analysis fails to show that offspring sex had any direct impact on maternal fertility, sibling survivorship, birth spacing, or reproductive span. Instead, the results indicate that fertility decisions were heavily affected by proximate factors such as child mortality and gender preferences. Families who had experienced child death were swift to substitute the loss with another pregnancy—a phenomenon known as replacement strategy. Similarly, …
Metformin and health outcomes:An umbrella review of systematic reviews with meta-analyses
2021
Background:\ud \ud The objective was to capture the breadth of outcomes that have been associated with metformin use and to systematically assess the quality, strength and credibility of these associations using the umbrella review methodology.\ud \ud Methods:\ud \ud Four major databases were searched until 31 May 2020. Meta‐analyses of observational studies and meta‐analyses of randomized controlled trials (RCTs) (including active and placebo control arms) were included.\ud \ud Results:\ud \ud From 175 eligible publications, we identified 427 different meta‐analyses, including 167 meta‐analyses of observational studies, 147 meta‐analyses of RCTs for metformin vs placebo/no treatment and 11…
Effects of different kinds of essentiality on sequence evolution of human testis proteins
2016
We asked if essentiality for either fertility or viability differentially affects sequence evolution of human testis proteins. Based on murine knockout data, we classified a set of 965 proteins expressed in human seminiferous tubules into three categories: proteins essential for prepubertal survival (“lethality proteins”), associated with male sub- or infertility (“male sub-/infertility proteins”), and nonessential proteins. In our testis protein dataset, lethality genes evolved significantly slower than nonessential and male sub-/infertility genes, which is in line with other authors’ findings. Using tissue specificity, connectivity in the protein-protein interaction (PPI) network, and mul…
Heritability Estimates of Differences in Arbitrary Embryonic Mortality Traits in Turkeys
1971
Abstract INTRODUCTION SPECIFIC embryonic abnormalities in Broad Breasted Bronze turkeys which contributed to low hatchability were classified into eight groups which are referred to as traits in this paper. References to these traits or similar abnormalities in chickens and turkeys are shown in Table 1. The objective of this study was to determine the differences in the rates, relative to unhatched fertile eggs, at which these specific traits could be changed by artificial selection which was accompanied by inbreeding. Rapid changes would indicate the traits more responsive to selection. MATERIALS AND METHODS Four different strains of Broad Breasted Bronze turkeys were introduced as eggs to…
PanCareLIFE
2018
Aims: Survival after cancer diagnosed during childhood or adolescence continues to improve with new treatments and supportive therapies. Optimal long-term care requires that risks to vulnerable organs are clearly defined and translated into guidelines that are implemented into practice. PanCareLIFE is a pan-European consortium that addresses survivorship issues comprising fertility, hearing impairment and quality of life. This article describes the scientific basis of PanCareLIFE's studies.Methods: PanCareLIFE involves 17 partner institutions from eight European countries, with additional 11 data providers from five other countries. Study designs and methods include molecular genetic, cohor…
Meiosis in translocation heterozygotes in the mosquito Culex pipiens.
1971
Adult Culex pipiens males irradiated with both X-rays and neutrons were crossed to untreated females and F1-egg rafts were checked for dominant lethality. F1-progenies were outcrossed with normal individuals in order to obtain lines with inherited semisterility. From a total of 120 lines that showed a certain amount of sterility 12 lines were studied cytologically. 10 lines showed reciprocal chromosome exchanges.—At late pachytene and diplotene cross configurations with large asynaptic regions at the center of the cross are obligatory. Bivalents, chains of three, chains of four, and ring configurations are present at metaphase and anaphase I. The different frequencies of the occurrence of s…
Subzonal insemination, partial zona dissection or intracytoplasmic sperm injection? An easy decision?
1995
This review aims to analyse and compare the results to date of subzonal insemination (SUZI), partial zona dissection (PZD) and intracytoplasmic sperm injection (ICSI) to evaluate critically whether it is now possible to replace SUZI and PZD by ICSI. It appears that ICSI is a much more efficient assisted reproduction technique than SUZI and PZD for resolving cases of severe male infertility and/or repeated failure of conventional in-vitro fertilization (IVF). For ICSI compared with SUZI and PZD, fertilization (49.4, 17.7 and 16.8% respectively), percentage of patients reaching embryo transfer (91.0, 55.1 and 23.3% respectively), percentage of transfers performed with two or three embryos (83…
Tales of healthy men: Male reproductive bodies in biomedicine from ‘Lebensborn’ to sperm banks
2012
Using the example of ‘sperm tales’, borne out of the biomedical technologies that went hand in hand with the establishment of the ‘science of man’ (andrology), the article engages with the epistemic evolution of interrelated biomedical theories and concepts of what constitutes a ‘healthy’ reproductive male body. The article asks: how has the normative ideal male body been either perpetuated or interrogated through these tales of male reproduction at the interface between scientific and medical technologies? And how were changes to the normalization of male bodies central to clinical practices and cultural understandings of health and illness? With many aspects of the medical history of male…
Male infertility and mitochondrial DNA
2004
The mitochondrial machinery plays a key role in the energy production and maintenance of spermatozoa motility. In this paper 200 idiopathic oligo-asthenozoospermic patients were classified on the basis of rapid progressive motility ("a") and sperm concentration. Mitochondrial enzymatic activity was studied and correlated to the viability of sperm cells. Mitochondrial DNA purified from both motile and non-motile sperm of the same individuals was amplificated using PCR. Results suggested that only motile sperm have organelles functional in oxygen consumption, unequivocally demonstrating that motility depends on the mitochondrial activity. Mitochondrial DNA of oligo-asthenozoospermic patients …