نتایج جستجو برای: sperm density

تعداد نتایج: 446003  

2017

Patients with sickle cell disease (SCD), especially males, face a key problem in the form of infertility. Apart from low serum testosterone, abnormalities involving accessory sex organs are also observed in these patients. Infertility is a known complication among males with SCD, and it comes about due to reasons such as impotence, relative primary gonadal failure, priapism, and delayed or impa...

Journal: :Human reproduction 2009
M Kheirollahi-Kouhestani S Razavi M Tavalaee M R Deemeh M Mardani J Moshtaghian M H Nasr-Esfahani

BACKGROUND Reducing the percentage of sperm anomalies in insemination samples remains a goal to be achieved in the intra-cytoplasmic sperm insemination (ICSI) procedure. The aim of this study was to evaluate the efficiency of density gradient centrifugation (DGC) and Zeta methods to recover sperm with intact chromatin, and to evaluate whether the combined DGC/Zeta procedure improved ICSI outcom...

Journal: :Indian journal of physiology and pharmacology 2005
Nibedita Naha R B Bhar A Mukherjee Amal Roy Chowdhury

Lead is one of the industrially heavy metals that caused adverse effects on male reproductive system among battery factory workers, but information on the possible impact of lead on the structural integrity of sperm cell is limited. Thus present study was undertaken to assess the structural details of human spermatozoa of lead acid battery factory workers. Blood and semen samples were collected...

Journal: :The American naturalist 2016
Daniel K Okamoto

Competition among gametes for fertilization imposes strong selection. For external fertilizers, this selective pressure extends to eggs for which spawning conditions can range from sperm limitation (competition among eggs) to sexual conflict (overabundance of competing sperm toxic to eggs). Yet existing fertilization models ignore dynamics that can alter the functional nature of gamete interact...

2008
Martin Psenicka

sperm morphology, biochemistry and physiology were compared between siberian sturgeon Acipenser baerii and sterlet A. ruthenus in the present study. We observed wide morphological variations between spermatozoa of the two species. the average length of the spermatozoon head was 7.01 and 5.14 μm in A. baerii and A. ruthenus, respectively. Significant differences were observed in terms of Na+, k+...

2013
Rakesh K Sharma

This chapter will discuss the various sperm preparation and selection techniques used to process sperm for use with assisted reproductive techniques: swim-down, swim-up, migrationsedimentation, density gradient centrifugation, magnetic activated cell sorting, and glass wool filtration. It will also explain the procedures used to prepare viscous semen samples as well as when to obtain and prepar...

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...

2013
Pranab J. Das Fiona McCarthy Monika Vishnoi Nandina Paria Cathy Gresham Gang Li Priyanka Kachroo A. Kendrick Sudderth Sheila Teague Charles C. Love Dickson D. Varner Bhanu P. Chowdhary Terje Raudsepp

Mature mammalian sperm contain a complex population of RNAs some of which might regulate spermatogenesis while others probably play a role in fertilization and early development. Due to this limited knowledge, the biological functions of sperm RNAs remain enigmatic. Here we report the first characterization of the global transcriptome of the sperm of fertile stallions. The findings improved und...

Journal: :Journal of morphology 2008
Dustin S Siegel David M Sever

Upon copulation in female Agkistrodon piscivorus, sperm migrate up the oviduct to sperm storage tubules (SSTs) in the posterior infundibulum. The epithelium of the SSTs is composed of ciliated and secretory cells and differs ultrastructurally from that of the epithelium lining the lumen of the posterior infundibulum. Sperm pass through an area composed primarily of ciliated cells at the opening...

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