نتایج جستجو برای: gradient selected sperm
تعداد نتایج: 533627 فیلتر نتایج به سال:
BACKGROUND Detection of apoptosis in sperm samples may help evaluate sperm quality. Recently, it has been suggested that in some ejaculated sperm populations, apoptosis is caspase dependent. The aim of this study was to investigate the presence of activated caspases and examine possible correlations with apoptosis and sperm parameters in semen samples prepared for IVF. METHODS To detect activ...
This study examines the use of optical trapping as a quantitative measure of sperm motility. The effects of laser trap duration and laser trapping power on sperm motility are described between sperm swimming force, swimmimg speed, and speed of progression (SOP) score. Sperm (SOP scores of 2-4) were trapped by a continuous-wave 1064 nm single-point gradient laser trap. Trap duration effects were...
OBJECTIVE To evaluate sperm DNA fragmentation and semen parameters to diagnose male factor infertility and predict pregnancy after IVF. DESIGN Prospective study. SETTING Academic research laboratory. PATIENT(S) Seventy-five couples undergoing IVF and 28 fertile donors. INTERVENTION(S) Sperm DNA fragmentation was measured by the alkaline Comet assay in semen and sperm after density gradi...
STUDY QUESTION Does CatSper have a role in the achievement of human sperm motility and in the Progesterone (P)-induced acrosome reaction (AR)? SUMMARY ANSWER CatSper1 expression is associated with human sperm progressive motility and the P-induced AR; it may have a role in the pathogenesis of asthenozoospermia. WHAT IS KNOWN ALREADY Knockout mice for any of the Catsper family genes fail to ...
Sperm motility is an important concept in fertility research. To this end, single spot laser tweezers have been used to quantitatively analyze the motility of individual sperm. However, this method is limited with throughput (single sperm per spot), lacks the ability of in-situ sorting based on motility and chemotaxis, requires high laser power (hundreds of milliWatts) and can not be used to dy...
The purpose of this study was to characterize highly enriched human spermatozoa membrane proteins by two-dimensional electrophoresis and computer image analysis. Sperm membrane proteins were extracted by detergent solubilization from three different preparations: 1) washed semen cells following centrifugation and three wash steps in Ham's F-10 medium (the standard sperm preparation, which is co...
In many broadcast-spawning marine organisms, oocytes release chemicals that guide conspecific spermatozoa towards them through chemotaxis. In the sea urchin Lytechinus pictus, the chemoattractant peptide speract triggers a train of fluctuations of intracellular Ca(2+) concentration in the sperm flagella. Each transient Ca(2+) elevation leads to a momentary increase in flagellar bending asymmetr...
OBJECTIVE To investigate the role of DNA damage induced by beta-nicotinamide adenine dinucleotide phosphate (NADPH) in human spermatozoa. DESIGN Prospective controlled study. SETTING Male infertility clinic at the Glickman Urological Institute, Cleveland Clinic Foundation, Cleveland, Ohio. PATIENT(S) Twenty-eight men undergoing infertility screening. INTERVENTION(S) Chemiluminescence as...
Optical trapping is a noninvasive biophotonic tool that has been developed to study the physiological and biomechanical properties of cells. The custom-designed optical system is built to direct near-infrared laser light into an inverted microscope to create a single-point three-dimensional gradient laser trap at the microscope focal point. A real-time automated tracking and trapping system (RA...
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