Semen

About: Semen is a research topic. Over the lifetime, 14571 publications have been published within this topic receiving 407739 citations. The topic is also known as: come & ejaculate.

Isolation and Characterization of a Semen-Specific Protein from Human Seminal Plasma: A Potential New Marker for Semen Identification

Abstract: The identification of semen is of paramount importance in the investigation of rape and other crimes involving sexual assault. The most commonly used procedures for semen identification center on the detection of sperm or the detection of prostatic acid phosphatase activity; methods involving the detection of spermine, choline, or semen antigens are less commonly employed. Unfortunately, none of these procedures is without one or more significant problems. For example, sperm will not be found in the semen of vasectomized or aspermic males; moreover, sperm are mechanically labile and their unequivocal identification in suspected semen stains is often difficult. Also, sperm are cleared from the vagina fairly rapidly and hence may not be found in postcoital vaginal washings. Thus the failure to detect sperm in suspect material by no means counterindicates semen. In the case of the acid phosphatase test, the problems are different. Acid phosphatase is not at all unique to semen or prostatic tissue; this enzyme activity is ubiquitous in nature. Moreover, there is evidence that prostatic acid phosphatase and the acid phosphatase found in normal vaginal secretions are genetically identical and that both are genetically identical to lysosomal acid phosphatase found in most tissues; therefore, the genetic basis of specificity of the acid phosphatase test is in question. The quantitative test can only be based on the extraordinarily high level of acid phosphatase activity in semen; the low levels of activity often found in postcoital vaginal washings are thus equivocal with respect to the question of semen detection. The other tests for semen identification are similarly suspect in reference to their specificity.

Sperm function tests and fertility.

Abstract: Traditionally, the diagnosis of male infertility has depended upon a descriptive evaluation of human semen with emphasis on the number of spermatozoa that are present in the ejaculate, their motility and their morphology. The fundamental tenet underlying this approach is that male fertility can be defined by reference to a threshold concentration of motile, morphologically normal spermatozoa that must be exceeded in order to achieve conception. Many independent studies have demonstrated that this fundamental concept is flawed and, in reality, it is not so much the absolute number of spermatozoa that determines fertility, but their functional competence. In the light of this conclusion, a range of in vitro tests have been developed to monitor various aspects of sperm function including their potential for movement, cervical mucus penetration, capacitation, zona recognition, the acrosome reaction and sperm-oocyte fusion. Such functional assays have been found to predict the fertilizing capacity of human spermatozoa in vitro and in vivo with some accuracy. Recent developments in this field include the introduction of tests to assess the degree to which human spermatozoa have suffered oxidative stress as well as the integrity of their nuclear and mitochondrial DNA. Such assessments not only yield information on the fertilizing capacity of human spermatozoa but also their ability to support normal embryonic development.

Vitamin D receptor and vitamin D metabolizing enzymes are expressed in the human male reproductive tract

Abstract: background: The vitamin D receptor (VDR) is expressed in human testis, and vitamin D (VD) has been suggested to affect survival and function of mature spermatozoa. Indeed, VDR knockout mice and VD deficient rats show decreased sperm counts and low fertility. However, the cellular response to VD is complex, since it is not solely dependent on VDR expression, but also on cellular uptake of circulating VD and presence and activity of VD metabolizing enzymes. Expression of VD metabolizing enzymes has not previously been investigated in human testis and male reproductive tract. Therefore, we performed a comprehensive analysis of the expression of VDR, VD activating (CYP2R1, CYP27A1, CYP27B1) and inactivating (CYP24A1) enzymes in the testis, epididymis, seminal vesicle (SV), prostate and spermatozoa. methods: Tissue samples were obtained after orchiectomy (testis n ¼ 13; epididymis n ¼ 7), prostatectomy (prostate n ¼ 5 and SVs n ¼ 3) and semen samples obtained after ejaculation (n ¼ 13). mRNA was detected with RT– PCR and expression of proteins was determined by immunohistochemistry. results: VDR and VD metabolizing enzymes were concomitantly expressed in round and elongated spermatids, vesicles within the caput epididymis, and glandular epithelium of cauda epididymis, SV and prostate. The expression pattern in ejaculated spermatozoa varied, although, concomitant expression of VDR, CYP2R1, CYP27B1 and CYP24A1 was observed in neck and midpiece in a subpopulation of mature spermatozoa. conclusion: On the basis of the marked expression of VDR and the VD metabolizing enzymes in human testis, ejaculatory tract and mature spermatozoa, we suggest that VD is important for spermatogenesis and maturation of human spermatozoa.