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Genetics and exercise: an introduction
Published in Adam P. Sharples, James P. Morton, Henning Wackerhage, Molecular Exercise Physiology, 2022
Claude Bouchard, Henning Wackerhage
Mature sperms and oocytes are haploid cells, carrying only 23 instead of the normal 2 × 23 chromosomes in somatic cells. So how do we get from a normal cell with 46 chromosomes to a gamete? The answer is that this occurs during meiosis, a process by which female and male haploid gametes are generated. Spermatogenesis occurs in the testes and produces sperm in abundance. A subpopulation of these cells, spermatocytes, undergoes two meiotic divisions to form four haploid sperm cells. The process of female gamete production in the ovaries is called oogenesis. It begins during foetal development when thousands of primary oocytes are formed through mitosis. Primary oocytes enter meiosis but their meiotic progression is arrested until puberty with the onset of the menstrual cycle.
Equine Semen Preservation: Current and Future Trends
Published in Juan Carlos Gardón, Katy Satué, Biotechnologies Applied to Animal Reproduction, 2020
Lydia Gil Huerta, Cristina Álvarez, Victoria Luño Lázaro
Cryopreserved semen involves storage at extremely low temperatures in liquid nitrogen (–196ºC). If the sperms are able to withstand the freeze-thaw cycles, sperm viability could be maintained indefinitely since the metabolic activity is considered null at this temperature (Brinsko et al., 2011).
Radiation Damage of the Reproductive Organs
Published in Kedar N. Prasad, Handbook of RADIOBIOLOGY, 2020
The processes of the formation of sperm are referred to as spermatogenesis. The highly proliferating spermatogonia line the seminiferous tubules and give rise to primary and secondary spermatocytes, which then form spermatids. The spermatids do not divide. Each spermatid matures into one spermatozoon. On the criterion of cell death, spermatogonia are most radiosensitive, whereas spermatids and spermatozoa are most radioresistant, but the possibility of genetic damage is high for all cellular elements. The interstitial cells that produce male hormone are also highly radioresistant. Therefore, men exposed at a sterilizing dose (500–600 rads) of radiation retain their fertility and produce seminal and prostatic fluid without sperm for a while. After irradiation, the testis becomes smaller and softer, and may become sterile. However, no change in the beard, voice, or social behavior has been observed.
Atrazine neural and reproductive toxicity
Published in Toxin Reviews, 2022
Hamidreza Sadeghnia, Sara Shahba, Alireza Ebrahimzadeh-Bideskan, Shabnam Mohammadi, Amir Mohammad Malvandi, Abbas Mohammadipour
Sperm is produced from germinal cells through spermatogenesis. The primary cell involved in spermatogenesis is spermatogonia (Fani et al. 2018). Fani et al. (2018) showed that atrazine dysregulates the process of spermatogenesis (Fani et al. 2018). This study revealed that atrazine exposure resulted in increased apoptosis in spermatogonia and primary spermatocytes and reduced sperm quality in mice. Another study reported that atrazine administration (300 mg/kg) to rats decreases sperm motility and counts by 25.8% and 27.6%, respectively (Kale et al. 2018). An increase in apoptotic cells number may be due to oxidative stress induced by atrazine. According to Kale et al. (2018), atrazine-induced oxidative damage in testis is associated with cyclooxygenase-2 (COX-2), an enzyme involved in various pathological conditions, and able to induce oxidative stress (Chae et al. 2008, Kale et al. 2018). Kale et al. (2018) investigated the effect of COX-2 inhibitor against atrazine-induced toxicity and observed histopathological improvement of testis in treated rats, which indicates that COX-2 plays a crucial role in atrazine-induced damages.
How fixed versus variable gonadotropin dose during controlled ovarian stimulation could influence the management of infertility patients undergoing IVF treatment: a national Delphi consensus
Published in Gynecological Endocrinology, 2021
Carlo Bulletti, Adolfo Allegra, Mario Mignini Renzini, Alberto Vaiarelli
Infertility is defined as the failure to achieve a pregnancy after at least 12 months of unprotected intercourses, and it is known to be affecting about 15% of couples [1]. In recent years we have observed a further increase in infertility worldwide, following the vast socio-economic changes in the modern western societies, which has led to an increased number of women seeking ART to conceive. Several approaches are currently been available to manage infertility in patients, from intrauterine insemination (IUI), to in vitro fertilization (IVF), intra-cytoplasmatic sperm injection (ICSI), TESE (testicular sperm extraction), and preimplantation genetic testing (PGT). Despite the technological developments and progress made in the past few decades (such as blastocyst culture, single embryo transfer (SET), cryopreservation and PGT for aneuploidies (PGT-A) or for monogenic disease (PGT-M)), the most sensitive ART step still remains the controlled ovarian stimulation (COS) phase [2,3].
How Do New Media Influence Youths’ Health Literacy? Exploring the Effects of Media Channel and Content on Safer Sex Literacy
Published in International Journal of Sexual Health, 2018
Wan-Ying Lin, Xinzhi Zhang, Bolin Cao
To compose a scale on safer sex literacy, we adopted 10 questions from previous research (Lou & Chen, 2009; See et al., 2008) that focused on sexual knowledge among adolescents. The questionnaire in See et al.’s study (2008, p. 23) was presented in Chinese. We slightly modified the wording to fit the Hong Kong context. The scale consisted of 10 statements, some correct and others incorrect. For example, “Male’s sperm can survive two to three days in the female’s body” [correct]. For another, “A female will not get pregnant after her first sexual intercourse, or having sex occasionally” [incorrect]. For each statement, the participants were asked to evaluate whether it was “true,” “false,” or “don’t know.” If the participants correctly evaluated a statement, they scored 1 for that item; otherwise (for “wrong” and “don’t know” answers), they scored 0. The level of safer sex literacy was created by summing up the scores for all 10 items, with a higher score suggesting a higher level of literacy on safer sex issues. A paired-sample t-test reported a significant difference, or an increase, between the pretest (M = 6.47, SD = 1.67, KR-20 = .46) and the posttest scores (M = 7.58, SD = 1.24, KR-20 = .42); t(143) = −7.72, p < .001, Cohen’s d = .64. Table 1 lists the questions with the correct statements noted.