نتایج جستجو برای: sperm production

تعداد نتایج: 638025  

A Hosseinzadeh Colagar M Firouzi, M Houshmand N Khosronezhad

Background Almost 15% of couples suffer from infertility and the men account for 50% of infertility factors. The most prevalent reason of male infertility is due to problems in sperm production that include low number of sperms or low mobility of sperm and production of sperm with improperly function. Sperm cell needs ATP to perform its functions which provided by mitochondria. Presence of poin...

2009
HAMIDA BEGUM

Male and female partner of a couple must be standard and fit to have the capacity to procreate. Studies confirm that male sperm counts are declining and environmental factors as pesticides, exogenous estrogen, heavy metals negatively impact spermatogenesis without any obvious anatomical defects. So, a number of nutritional therapies have been shown to improve sperm count and motility as carniti...

Journal: :Journal of animal science 2012
B A Freking P H Purdy S F Spiller C S Welsh H D Blackburn

Selection for 11 generations in swine for ovulation rate (OR) or uterine capacity (UC) resulted in significant changes in component traits of litter size. Our objective was to conserve the unique germplasm for the future and to characterize sperm quality as a correlated response to the selection criterion imposed compared to an unselected control line (CO). Boars representing genetic diversity ...

2012
Mohammad Ali Ghaffari Morad Rostami

BACKGROUND Nitric oxide (NO) is synthesized from L-arginine by a family of enzymes known as nitric oxide synthases. Low concentrations of NO is essential in biology and physiology of spermatozoa, but high amounts of NO is toxic and has negative effects on sperm functions. Moreover, sperm membrane contains high concentrations of polyunsaturated fatty acids that are highly susceptible to oxidativ...

Journal: :The Journal of urology 2013
Louis Bujan Marie Walschaerts Nathalie Moinard Sylvianne Hennebicq Jacqueline Saias Florence Brugnon Jacques Auger Isabelle Berthaut Ethel Szerman Myriam Daudin Nathalie Rives

OBJECTIVE To determine the consequences of adjuvant testicular germ cell tumor treatment (TGCT) on sperm characteristics and sperm DNA, and to evaluate the predictors of sperm recovery. DESIGN Multicenter prospective longitudinal study of patients analyzed before treatment and after 3, 6, 12, and 24 months. SETTING University hospitals. PATIENT(S) One hundred twenty-nine volunteer TGCT pa...

Journal: :Journal of insect physiology 2001
R R. Snook T A. Markow

In Drosophila species of the obscura group, males exhibit sperm-heteromorphism, simultaneously producing both long sperm, capable of fertilization, and short sperm that are not. The production of multiple sperm types calls into question whether mating system correlates, such as sperm length and number trade-offs and female remating behavior, are the same as previously described in sperm-monomor...

Journal: :Reproduction 2011
Stefan Lüpold Joachim Wistuba Oliver S Damm James W Rivers Tim R Birkhead

The outcome of sperm competition (i.e. competition for fertilization between ejaculates from different males) is primarily determined by the relative number and quality of rival sperm. Therefore, the testes are under strong selection to maximize both sperm number and quality, which are likely to result in trade-offs in the process of spermatogenesis (e.g. between the rate of spermatogenesis and...

2017
Chiara Zerbinati Luisa Caponecchia Rosa Puca Marco Ciacciarelli Pietro Salacone Annalisa Sebastianelli Antonio Pastore Giovanni Palleschi Vincenzo Petrozza Natale Porta Rocco Rago Antonio Carbone Luigi Iuliano

Cholesterol is a main lipid component of sperm cell that is essential for sperm membrane fluidity, capacitation, and acrosomal reaction. Recent data obtained in bovine sperm showed that sperm capacitation is associated to the formation of oxysterols, oxidized products of cholesterol. The aim of this study was to profile oxysterol content in human semen, and to investigate their potential role i...

Journal: :Journal of andrology 1988
R J Aitken J S Clarkson

The mechanisms responsible for mediating the influence of sperm preparation protocols on human sperm function have been investigated. Techniques that involved the separation of motile spermatozoa prior to centrifugation were found to yield sperm suspensions of highest quality. If the spermatozoa were centrifuged prior to isolation of the motile cells, sperm function was impaired. The detrimenta...

2015

Sexually selected traits are often driven to costly extremes by persistent directional selection. Energy acquisition and allocation can therefore influence variation in traits subject to both precopulatory and postcopulatory sexual selection, though the later have received much less attention. We tested the condition dependence of sperm morphology, sperm count, and fertilization success in a pr...

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