نتایج جستجو برای: sperm type
تعداد نتایج: 1375947 فیلتر نتایج به سال:
In Drosophila ananassae, female remating with respect to productivity and sperm displacement was studied by employing different mutant strains and a wild type strain. In all the experiments, the continuous confinement technique was used. The comparison of productivity between once-mated (control) and remated females reveals that the productivity of remated females is significantly higher than t...
Specific peptides contained within the extracellular layer, or jelly coat, of a sea urchin egg have been hypothesized to play an important role in fertilization, though separate accounting of the effects of chemoattraction, chemokinesis, sperm agglomeration and the other possible roles of the jelly coat have not been reported. In the present study, we used a microfluidic device that allowed det...
Sperm flagellar motion is the outcome of a dynamic interplay between the axonemal cytoskeleton, the peri-axonemal accessory structures, and multiple regulatory networks that coordinate to produce flagellar beat and waveform. Tektins are conserved components of the flagellar proteome in evolutionarily diverse species and are believed to play essential roles in the mechanics of sperm motility. Us...
Predetermination of sex in livestock offspring is in great demand and is of critical importance to providing for the most efficient production of the world's food supply. With the changes that have taken place in animal agriculture over the past generation the application of sex preselection to production systems becomes increasingly necessary. The current technology is based on the well-known ...
introduction: transplantation of germ cells restores the male fertility. nevertheless, a lot of questions remain incompletely resolved. the aim of this study was to evaluate in vitro colonization efficiency of germ cells and sperm production capacity of spermatogonial cells before and after culture by sperm number assay in epididymis of recipient mice. materials and methods: we developed a sert...
background: so far, many studies investigated factors that affect pregnancy rates after intrauterine insemination (iui). various investigators have not agreed on the nature and ranking of these criteria. objective: the aim of this study was to assess the predictive factors for pregnancy rate after controlled ovarian hyperstimulation (coh)/ iui. materials and methods: retrospective study of all ...
OBJECTIVE Determine whether testicular sperm extractions and pregnancy outcomes are influenced by male and female infertility diagnoses, location of surgical center and time to cryopreservation. PATIENTS One hundred and thirty men undergoing testicular sperm extraction and 76 couples undergoing 123 in vitro fertilization cycles with testicular sperm. OUTCOME MEASURES Successful sperm recove...
Vasectomy reversal involves either vasovasostomy (VV) or epididymovasostomy (EV), and rates of epididymal obstruction and EV increase with time after vasectomy. However, as older vasectomies may not require EV for successful reversal, we hypothesized that sperm production falls after vasectomy and can protect the system from epididymal blowout. Our objective was to define how the need for EV at...
AIM The aim of this study was to evaluate the hemodynamics of varicocele using Doppler ultrasonography and scrotal scintigraphy, and to compare the value of these two methods in the prediction of seminal improvement after varicocelectomy. MATERIALS AND METHODS A total of 40 men with left sided varicocele presented for surgery because of infertility of at least one year in duration. Preoperati...
Male and female sexes have evolved repeatedly in eukaryotes but the origins of dimorphic sexes and their relationship to mating types in unicellular species are not understood. Volvocine algae include isogamous species such as Chlamydomonas reinhardtii, with two equal-sized mating types, and oogamous multicellular species such as Volvox carteri with sperm-producing males and egg-producing femal...
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