نتایج جستجو برای: sperm separation

تعداد نتایج: 159557  

Journal: :Human reproduction 2005
C Ainsworth B Nixon R J Aitken

BACKGROUND Optimization of assisted conception outcomes involves the development of rapid, safe, effective techniques for the isolation of functional human spermatozoa free from significant DNA damage. In this study we describe a novel electrophoretic sperm isolation technique that achieves these objectives. METHODS The separation system consisted of a cassette comprising two 400 mul chambers...

Journal: :Journal of evolutionary biology 2015
M Tourmente J Delbarco Trillo E R S Roldan

Post-copulatory sexual selection, in the form sperm competition, has influenced the evolution of several male reproductive traits. However, theory predicts that sperm competition would lead to trade-offs between numbers and size of spermatozoa because increased costs per cell would result in a reduction of sperm number if both traits share the same energetic budget. Theoretical models have prop...

Journal: :Fertility and sterility 2009
Reda Z Mahfouz Rakesh K Sharma Tamer M Said Juris Erenpreiss Ashok Agarwal

OBJECTIVE To examine the relationship among sperm apoptosis, sperm chromatin status, and DNA ploidy in different sperm fractions. DESIGN Prospective study. SETTING Reproductive research center in a tertiary care hospital. INTERVENTION(S) Sperm prepared by density gradient were evaluated for sperm count, motility, apoptosis, and sperm chromatin assessment. MAIN OUTCOME MEASURE(S) Sperm c...

Journal: :The International journal of developmental biology 2008
Montserrat Gomendio Eduardo R S Roldan

Sperm competition is now recognised as a potent selective force shaping many male reproductive traits. While the influence of sperm competition on sperm number is widely accepted, its effects upon sperm size remain controversial. It had been traditionally assumed that there is a trade-off between sperm number and sperm size, so that an increase in sperm number would result in a decrease in sper...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2008
Angela J Crean Dustin J Marshall

Sperm competition has classically been thought to maintain anisogamy (large eggs and smaller sperm) because males are thought to maximize their chance of winning fertilizations by trading sperm size for number. More recently it has been recognized that sperm quality (e.g., size, velocity) can also influence sperm competition, although studies have yielded conflicting results. Because sex evolve...

Journal: :Human fertility 2010
Sherman J Silber

It is often questioned whether sperm parameters, including whether retrieved or ejaculated, have any effect on intracytoplasmic sperm injection (ICSI) results. Do severe spermatogenic defects affect embryo quality or pregnancy rate? Further, does it matter in azoospermic patients whether the sperm source is testicular or epididymal? Our studies show there is no significant difference in results...

1998
C. D. MCDANIEL

A new instrument for assessing mammalian semen attributes, the Sperm Quality Analyzer, was evaluated as a potential tool for determining rooster sperm quality. The Sperm Quality Analyzer measures the “activity” of sperm in a semen sample as the sperm motility index (SMI). The SMI is defined as the number and amplitude of deflections in a light path per second as a result of sperm movement wit...

Journal: :The FASEB Journal 2021

Sperm acquire the ability to fertilize in a process called capacitation and undergo hyperactivation, change motility pattern, which depends on Ca2+ transport by CatSper channels. is essential for fertilization it subjected complex regulation that not fully understood. Here, we report similar CatSper, Cdc42 distribution principal piece confined four linear domains this localization disrupted Cat...

Journal: :Molecular human reproduction 2014
John L Fitzpatrick Stefan Lüpold

Sperm experience intense and varied selection that dramatically impacts the evolution of sperm quality. Selection acts to ensure that sperm are fertilization-competent and able to overcome the many challenges experienced on their way towards eggs. However, simply being able to fertilize an egg is not enough to ensure male fertility in most species. Owing to the prevalence of female multiple mat...

2013
Oliver Vöcking Gabriele Uhl Peter Michalik

Storage of sperm inside the female genital tract is an integral phase of reproduction in many animal species. The sperm storage site constitutes the arena for sperm activation, sperm competition and female sperm choice. Consequently, to understand animal mating systems information on the processes that occur from sperm transfer to fertilization is required. Here, we focus on sperm activation in...

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