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.

Subcompartmentalization of HIV-1 quasispecies between seminal cells and seminal plasma indicates their origin in distinct genital tissues.

Abstract: The mononuclear cells and plasma components of semen from HIV-infected subjects have been shown to contain HIV-1. However, there is very little information as to whether distinct HIV-1 population are present in these two seminal compartments or as to their tissue of origin. Phylogenetic analysis of nucleotide sequences of the C2-V5 region of the HIV-1 gp120 from HIV-1 RNA isolated from seminal cells and seminal plasma of five subjects indicates that the HIV-1 population derived from seminal plasma was distinct from that present in seminal cells. Such subcompartmentalization of HIV-1 between seminal cells and seminal plasma was detected as early as 3 months after seroconversion and persisted up to 38 months following seroconversion. Furthermore, comparison of HIV-1 sequences between testis and prostate tissues showed distinct HIV-1 populations in these tissue compartments. In situ real-time (Taqman) PCR analysis of prostate and testis tissues indicated that T lymphocytes were the predominant cells infected with HIV-1 in both of these tissues. Since seminal plasma is derived from prostate and most of the seminal cells originate from the rete testis and epididymis, these results are consistent with the idea that HIV-1 in seminal plasma is derived from the prostate, while HIV-1-infected cells in semen originate mostly from the rete testis and epididymis. These findings provide for the first time evidence of subcompartmentalization of HIV-1 in male genital organs and suggest that intervention strategies such as vasectomy may not prevent sexual transmission.

Induction of acrosome reaction in human spermatozoa used for subzonal insemination.

Abstract: Human spermatozoa were injected into the perivitelline space of oocytes from 43 couples (44 cycles) in whom fertilization had failed in conventional in-vitro fertilization (IVF). The spermatozoa were treated to enhance the percentage of acrosome-free spermatozoa either by incubation for 24 h in T6 medium with 50% follicular fluid (v/v) or by incubation for 24 h in T6 medium followed by electroporation and incubation for a few hours in T6 medium with 3.5 mM pentoxifylline. After these two procedures, the mean percentage of acrosome-free spermatozoa increased to 35.5 and 53.9% respectively. Up to three spermatozoa were injected into the perivitelline space of metaphase II oocytes; few oocytes were damaged during the injection procedure. The overall fertilization rate was 30.9% of the 433 oocytes that were intact after subzonal insemination. Only 3% of the injected oocytes had more than two pronuclei. The cleavage rate of the fertilized oocytes was 80%. There was no difference in the fertilization and cleavage rates between the two sperm treatment procedures. One, two or three embryos were replaced in 34 cycles and seven patients became pregnant. In three of the four ongoing pregnancies, prenatal diagnosis by amniocentesis indicated a normal karyotype.

External quality assessment for semen analysis and sperm antibody detection: results of a pilot scheme.

Abstract: The need for quality assurance in the seminology laboratory is clear, as the techniques of semen analysis and sperm antibody detection are just as susceptible to variation as any other routine pathology test. Semen samples were distributed to 20 laboratories on six occasions, four samples per distribution, for sperm concentration and morphology assessment under routine conditions, together with an equal number of serum samples for sperm antibody detection. The semen analysis results showed a wide range of values for any given sample, which did not seem to be related to the methodology used. However, this variation appears to be related to the presence of persistent errors, as most laboratories showed reasonable between-assay and within-assay variation. Detection of sperm antibodies by the tray agglutination, gelatin agglutination or indirect immunobead test showed a consistent discrimination between the intended positive and intended negative samples. However, the use of fluorescent microscopy was unable to do this. This study has shown the feasibility of operating external quality assessment schemes for semen analysis and sperm antibody detection. These schemes provide the opportunity for individual laboratories to fully evaluate their own methods against those of others and to determine the stages at which any errors occur. An increased number of participants will ultimately enable a systematic comparison of different methods.

Plasmalogen in ram semen, and its role in sperm metabolism.

Abstract: Whole semen can be stored successfully under both aerobic and anaerobic conditions, owing to the presence of glycolysable carbohydrate in the seminal plasma. However, if mammalian spermatozoa are separated from the seminal plasma by centrifuging and washing, they can maintain their motility only in the presence of oxygen. From this it has been inferred that when spermatozoa are deprived of fructose, which is the usual glycolysable carbohydrate in seminal plasma, they utilize the oxidation of intracellular reserves as a source of energy for motility. Lardy & Phillips (1941a, b, 1945) assigned this role of energy reserve to the phospholipids, pointing out that (i) the lipidphosphorus content diminishes during the aerobic storage of bull spermatozoa and (ii) the rate and duration of oxygen consumption are markedly increased when egg phospholipids, known to be composed chiefly of lecithin, are added to sperm suspensions in a sugar-free medium. These results were contradicted by Bomstein & Steberl (1957), who were unable to detect any appreciable changes in lipid phosphorus of washed bull spermatozoa during aerobic storage. These authors also concluded that the stimulation of oxygen consumption by exogenous phospholipids was not due to oxidation of these phospholipids. In similar experiments with ram spermatozoa analysis of phosphorus fractions gave no indication that the lipidphosphorus content diminishes during aerobic metabolism (Mann, 1958). The early experimental approaches to the participation of phospholipids in sperm metabolism were based upon two assumptions. The first of these, well entrenched since the early work by Miescher (1878, 1897), Mathews (1897) and Sano (1922), was that sperm phospholipids consist mainly of lecithin; the second was that any utilization of phospholipid during sperm metabolism would lead to liberation of the phosphorus in a non-lipid, acid-soluble form. Quite recently, however, investigations on the chemical nature of lipids present in ram spermatozoa have shown that there is no evidence for the presence of lecithin in the sperm cells and that the predominant intracellular lipid is of aldehydogenic nature, resembling the plasmalogens of brain and muscle (Lovern, Olley, Hartree & Mann, 1957). These findings, together with an earlier observation that a plasmalogen-like lipid is also present in bull semen (Boguth, 1952), made it desirable to reinvestigate the problem of the alleged relationship between lipids and the aerobic metabolism of mammalian spermatozoa. In this paper are reported analyses of plasmalogen and acyl ester in the lipids of ram semen with special reference to the behaviour of these substances during the aerobic as well as the anaerobic metabolism of spermatozoa.