نتایج جستجو برای: sperm preparation

تعداد نتایج: 211534  

Journal: :Reproductive biomedicine online 2006
Tamer M Said Ashok Agarwal Sonja Grunewald Manja Rasch Hans-Juergen Glander Uwe Paasch

Magnetic-activated cell sorting (MACS) using paramagnetic annexin V-conjugated microbeads eliminates spermatozoa with externalized phosphatidylserine, which is considered one of the features of apoptosis. The objective of this study was to evaluate sperm recovery following the use of MACS as a sperm preparation technique. Mature spermatozoa were separated and divided into two fractions: the fir...

2004
Gregg Gundersen

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...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1998
J A Zeh S D Newcomer D W Zeh

In most animal species, particularly those in which females engage in polyandry, mate choice is a sequential process in which a female must choose to mate or not to mate with each male encountered. Although a number of theoretical and empirical investigations have examined the effects of sequential mate choice on the operation of sexual selection, how females respond to solicitation by previous...

Journal: :Reproductive biomedicine online 2015
Qingling Yang Nan Zhang Feifei Zhao Wanli Zhao Shanjun Dai Jinhao Liu Ihtisham Bukhari Hang Xin Wenbing Niu Yingpu Sun

The ends of eukaryotic chromosomes contain specialized chromatin structures called telomeres, the length of which plays a key role in early human embryonic development. Although the effect of sperm preparation techniques on major sperm characteristics, such as concentration, motility and morphology have been previously documented, the possible status of telomere length and its relation with spe...

Journal: :Reproductive biomedicine online 2014
Annelies Thijssen Elke Klerkx Carin Huyser Eugene Bosmans Rudi Campo Willem Ombelet

This study investigated the effects of long-term (24h) in-vitro sperm incubation at room temperature (RT; 23°C) versus testis temperature (35°C) on various sperm-quality parameters. Semen samples (n=41) were prepared both by density-gradient centrifugation (DGC) and the swim-up technique in order to compare the influence of sperm preparation on sperm quality after incubation. Progressive motili...

Journal: :Asian journal of andrology 2012
Ralf Henkel

For assisted reproduction technologies (ART), numerous techniques were developed to isolate spermatozoa capable of fertilizing oocytes. While early methodologies only focused on isolating viable, motile spermatozoa, with progress of ART, particularly intracytoplasmic sperm injection (ICSI), it became clear that these parameters are insufficient for the identification of the most suitable sperma...

Henkel R

With the advent of human assisted reproduction in the year 1978 numerous techniques were developed to isolate spermatozoa capable to fertilize oocytes. While early methodologies only focused on the aim of isolating viable, motile spermatozoa, with further progress of assisted reproductive technology, particularly for ICSI, it rapidly became clear that these two parameters are insufficient for t...

Background: Telomeres are particular sequences of DNA located at the end of the eukaryotic chromosomes that are essential for genome integrity. Telomere length in spermatozoa differs among males, as well as spermatozoa. Also, decreased telomere length in spermatozoa of infertile men is associated with the reduction of fertility potential and embryo quality. Density gradient centrifugation (DGC)...

Journal: :Journal of the Chinese Medical Association : JCMA 2004
Yung-Chieh Tsai Mike Yan-Sheng Lin Sheng-Hsieg Chen Chieh-Yi Kang Yi-Ting Tsai Liang-Yin Lin Loo-Tao Chuan Kuo-Feng Huang

BACKGROUND Sperm preparation has play an integral part in the success of in-vitro fertilization. The aim of this study was to compare 2 different density gradient preparations for sperm separation in respect to sperm recovery, motility, motion parameters and clinical outcome after intrauterine insemination. METHODS One-hundred and 21 women who received intrauterine insemination due to ovulati...

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