نتایج جستجو برای: sperm rnas
تعداد نتایج: 70534 فیلتر نتایج به سال:
background: we performed this study to evaluate use of fresh and frozen sperm samples in non-obstructive azoospermia microdissection testicular sperm extraction (micro-tese-icsi) treatment. methods: we performed a total of 82 consecutive in vitro fertilization (ivf) cycles at fertijin ivf center in istanbul, turkey from january 2010 to march 2012. in 43 participants we used fresh sperm and froz...
Evolutionary biologists have argued that there should be a positive relationship between sperm size and sperm velocity, and that these traits influence a male's sperm competitiveness. However, comparative analyses investigating the evolutionary associations between sperm competition risk and sperm morphology have reported inconsistent patterns of association, and in vitro sperm competition expe...
Background: Ovarian cancer is the most fatal tumor of female's reproductive system, and several genetics and environmental factors are involved in its development. Various studies have already identified suitable biomarkers to facilitate the early detection, prognosis evaluation, and the assessment of treatment response. However, the aim of this review was to investigate the role of long non-co...
The present research was undertaken to determine the role of seminal plasma in heat stress (HS) infertility. Males were exposed to HS at 32 C or maintained at 21 C as controls. Centrifugation and reconstitution of semen samples created four final treatments: control sperm + control plasma (CsCp), control sperm + HS plasma (CsHp), HS sperm + HS plasma (HsHp), and HS sperm + control plasma (HsCp)...
Sperm competition is a prevalent phenomenon that drives the evolution of sperm function. High levels of sperm competition lead to increased metabolism to fuel higher sperm velocities. This enhanced metabolism can result in oxidative damage (including lipid peroxidation) and damage to the membrane. We hypothesized that in those species experiencing high levels of sperm competition there are chan...
Sperm surface beta 1,4-galactosyltransferase (GalTase) mediates fertilization in mice by binding to specific O-linked oligosaccharide ligands on the egg coat glycoprotein ZP3. Before binding the egg, sperm GalTase is masked by epididymally derived glycosides that are shed from the sperm surface during capacitation. After binding the egg, sperm-bound oligosaccharides on ZP3 induce the acrosome r...
OBJECTIVE To analyze cases in which no sperm could be identified after thawing among cryopreserved samples of rare or very low concentrations of sperm. DESIGN Retrospective, single-institution, cross-sectional. SETTING Male infertility clinic. PATIENT(S) We identified couples that underwent intracytoplasmic sperm injection (ICSI) with the use of either ejaculated or testicular cryopreserv...
The existence and evolutionary significance of sexual selection through sperm competition was first realized by Geoff Parker in a prescient and influential review published in 1970. Parker recognized that competition between males for fertilizations will continue after mating, if the sperm of two or more males overlap near the site of fertilization in females. The process of sperm competition w...
Fertilization is a cell-cell recognition process that occurs between two distinct cells: a small asymmetric and motile sperm cell and a large and nonmotile egg. The stages of fertilization can be divided into four processes: 1) sperm preparation, 2) sperm-egg recognition and binding, 3) sperm-egg fusion and 4) fusion of sperm and egg pronuclei and activation of the zygote. The specific structur...
BACKGROUND Sperm design varies enormously across species and sperm competition is thought to be a major factor influencing this variation. However, the functional significance of many sperm traits is still poorly understood. The sperm of most murid rodents are characterised by an apical hook of the sperm head that varies markedly in extent across species. In the European woodmouse Apodemus sylv...
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