Showing papers on "Semen published in 2001"
TL;DR: Threshold values for sperm concentration, motility, and morphology can be used to classify men as subfertile, of indeterminate fertility, or fertile and none of the measures are diagnostic of infertility.
Abstract: Background Although semen analysis is routinely used to evaluate the male partner in infertile couples, sperm measurements that discriminate between fertile and infertile men are not well defined. Methods We evaluated two semen specimens from each of the male partners in 765 infertile couples and 696 fertile couples at nine sites. The female partners in the infertile couples had normal results on fertility evaluation. The sperm concentration and motility were determined at the sites; semen smears were stained at the sites and shipped to a central laboratory for an assessment of morphologic features of sperm with the use of strict criteria. We used classification-and-regression-tree analysis to estimate threshold values for subfertility and fertility with respect to the sperm concentration, motility, and morphology. We also used an analysis of receiver-operating-characteristic curves to assess the relative value of these sperm measurements in discriminating between fertile and infertile men. Results The su...
1,129 citations
TL;DR: The weight of the evidence suggests that increased male age is associated with a decline in semen volume, sperm motility, and sperm morphology but not with sperm concentration.
644 citations
TL;DR: The strong correlation between sperm DD and DF, and the higher levels of sperm DNA damage in infertile compared with fertile men, indicate that male infertility is associated with poor sperm DNA integrity.
422 citations
TL;DR: The high levels of ROS production and DNA damage observed in immature spermatozoa may be indicative of derangements in the regulation of spermiogenesis, which is implicated in the pathogenesis of male infertility.
Abstract: BACKGROUND: Reactive oxygen species (ROS)-induced damage of membrane phospholipids and DNA in human spermatozoa has been implicated in the pathogenesis of male infertility. In this study, variations in ROS production, DNA structure (as measured by the sperm chromatin structure assay) and lipid composition, were studied in human spermatozoa at different stages of maturation. METHODS: Sperm subsets were isolated by discontinuous density gradient centrifugation of semen samples obtained from healthy donors and from infertility patients. RESULTS: DNA damage and ROS production were highest in immature spermatozoa with cytoplasmic retention and abnormal head morphology, and lowest in mature spermatozoa. Docosahexaenoic acid and sterol content were highest in immature germ cells and immature spermatozoa, and lowest in mature spermatozoa. The relative proportion of ROS-producing immature spermatozoa in the sample was directly correlated with DNA damage in mature spermatozoa, and inversely correlated with the recovery of motile spermatozoa. There was no correlation between DNA damage and sperm morphology in mature spermatozoa. CONCLUSIONS: The high levels of ROS production and DNA damage observed in immature spermatozoa may be indicative of derangements in the regulation of spermiogenesis. DNA damage in mature spermatozoa may be the result of oxidative damage by ROS-producing immature spermatozoa during sperm migration from the seminiferous tubules to the epididymis.
373 citations
TL;DR: The results demonstrated that deleterious effects sperm motility after cryopreservation in EYTG can be counteracted by adding various thiols at mM concentration, and indicated in the extender that the glutathione redox-cycle was deficient.
330 citations
TL;DR: There is significant cell-to-cell variation in ROS production in subsets of spermatozoa at different stages of maturation and that oxidative damage of mature spermatozosa by ROS-producing immature spermatoza during sperm migration from the seminiferous tubules to the epididymis may be an important cause of male infertility.
Abstract: BACKGROUND: Reactive oxygen species (ROS)-mediated damage to human spermatozoa has been implicated in the pathogenesis of male infertility. Although ROS production by human spermatozoa has been extensively studied, the cell-to-cell variation in ROS production by spermatozoa at different stages of maturation has never been investigated. METHODS: In this study, we determined ROS production by subsets of human spermatozoa at different stages of maturation isolated by density gradient centrifugation of ejaculated spermatozoa obtained from healthy donors and from patients attending a clinic for infertility screening. RESULTS: Four different fractions were obtained. ROS production was highest in immature spermatozoa with abnormal head morphology and cytoplasmic retention and lowest in mature spermatozoa and immature germ cells (P < 0.01). ROS production was highest in immature spermatozoa from males with abnormal semen parameters compared with donors (P < 0.0001) or patients with normal semen parameters (P 0.015). ROS production by immature spermatozoa was inversely correlated with the recovery of motile, mature spermatozoa in the high density fraction 4 (P 0.01). CONCLUSIONS: The results of this study indicate that there is significant cell-to-cell variation in ROS production in subsets of spermatozoa at different stages of maturation and that oxidative damage of mature spermatozoa by ROS-producing immature spermatozoa during sperm migration from the seminiferous tubules to the epididymis may be an important cause of male infertility.
326 citations
TL;DR: It is demonstrated that along with the classical semen parameters, the assessment of nuclear integrity improves the characterization of the semen sample and may be used as a tool for allocating patients to specific assisted reproduction treatments.
Abstract: Background With an increase in the use of assisted reproduction technologies the requirements of the diagnostic semen analysis are constantly changing. Methods Spermatozoa from patients undergoing IVF were analysed by examining the conventional semen parameters and DNA/chromatin integrity, using in-situ nick translation (NT) and the Chromomycin A(3) fluorochrome, which indirectly demonstrates a decreased presence of protamine. Samples were examined before and after preparation using discontinuous density gradient centrifugation. Results Density gradient centrifugation enriched samples by improving the percentage of morphologically normal forms by 138% and sperm nuclear integrity by 450%. Sperm nuclear integrity as assessed by in-situ nick translation (NT) demonstrated a very clear relationship with sperm concentration, motility and morphology. Morphology correlated with fertilization rates of patients undergoing IVF, while NT values of the spermatozoa post-preparation were significantly lower in pregnant patients. Conclusions We have demonstrated that along with the classical semen parameters, the assessment of nuclear integrity improves the characterization of the semen sample and may be used as a tool for allocating patients to specific assisted reproduction treatments.
280 citations
TL;DR: A ubiquitin-dependent, sperm quality control mechanism that resides in the mammalian epididymis, the site of sperm maturation and storage, is described and the surprising phenomenon of cell-surface ubiquitination in defective sperm is described.
Abstract: The normal structure and function of sperm are prerequisites for successful fertilization and embryonic development, but little is known about how defective sperm are eliminated during mammalian spermatogenesis. Here, we describe a ubiquitin-dependent, sperm quality control mechanism that resides in the mammalian epididymis, the site of sperm maturation and storage. We used immunofluorescence, electron microscopy, western blotting and pulse-chase experiments to show that ubiquitin is secreted by the epididymal epithelium and binds to the surface of defective sperm. Most of the ubiquitinated sperm are subsequently phagocytosed by the epididymal epithelial cells. A portion of defective sperm escapes phagocytosis and can be found in the ejaculate. Cultured epididymal cells maintain their ability to produce ubiquitin and phagocytose the defective sperm, as well as the ubiquitin-coated microspheres, in vitro. The surprising phenomenon of cell-surface ubiquitination in defective sperm provides a possible mechanism for sperm quality control in mammals and a new marker of semen abnormalities in men and animals.
273 citations
Journal Article•
TL;DR: Treatment with Maca resulted in increased seminal volume, sperm count per ejaculum, motile sperm count, and sperm motility and this was not related to dose of Maca.
Abstract: Aim: The present study was designed to determine the effect of a 4-month oral treatment with tablets of Lepidium meyenii (Maca) on seminal analysis in nine adult normal men aged 24-44 years old. Methods: Nine men received tablets of Maca (1500 or 3000 mg/day) for 4 months. Seminal analysis was performed according to guidelines of the World Health Organization (WHO). Serum luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin (PRL), testosterone (T) and estradiol (E 2 ) were measured before and after treatment. Results: Treatment with Maca resulted in increased seminal volume, sperm count per ejaculum, motile sperm count, and sperm motility. Serum hormone levels were not modified with Maca treatment. Increase of sperm count was not related to dose of Maca. Conclusion : Maca improved sperm production and sperm motility by mechanisms not related to LH, FSH, PRL, T and E 2 .
260 citations
TL;DR: Sperm viability and motility in both fresh and thawed samples were similar in classes H and A, while significantly lower values were measured in class L, indicating that active sperm lipid metabolism might be responsible for the increase in lipid content.
Abstract: The effect of cryopreservation on boar sperm viability, motility, lipid content and antioxidant enzymatic activities was studied. Three classes of semen were determined according to a cluster analysis on the basis of the proportion of live and dead cells after freezing and thawing. The classes identified were: high (H, n = 4), average (A, n = 12) and low (L, n = 3) viability. The concentration of sperm cells decreased from class H to A to L. Fresh semen samples with higher viability and a higher proportion of motile cells also maintained better quality after the freezing and thawing procedure. Sperm viability and motility in both fresh and thawed samples were similar in classes H and A, while significantly lower values were measured in class L. The relative decrease in sperm viability and motility after cryopreservation increased from class H to A to L. The lipid content of spermatozoa (micrograms per 10(9) cells) increased significantly after freezing and thawing in classes H and A but not in class L. This result indicated that active sperm lipid metabolism might be responsible for the increase in lipid content. Phospholipid and triacylglycerol contents increased whereas free cholesterol content decreased after thawing. The fatty acid composition of fresh spermatozoa was similar in all three classes. The proportion of polyunsaturated fatty acids decreased significantly after freezing and thawing, indicating contamination from the diluent or peroxidation. After freezing and thawing, superoxide dismutase activity in spermatozoa was significantly higher in class L than in classes H and A, which did not differ from each other.
249 citations
TL;DR: Investigation of the effects of cryopreservation on both DNA integrity and morphology of spermatozoa from fertile and infertile men found it had a detrimental effect on morphology of semen and prepared samples from fertile, and sperm morphology was significantly damaged by freeze-thawing.
Abstract: Cryopreservation of human spermatozoa is extensively used in artificial insemination and IVF programmes Despite various advances in cryopreservation methodology, the recovery rate of functional post-thaw spermatozoa remains mediocre, with sperm motility being significantly decreased after freezing This aim of this study was to investigate the effects of cryopreservation on both DNA integrity and morphology of spermatozoa from fertile and infertile men Semen samples were obtained from 17 fertile and 40 infertile men All samples were prepared by discontinuous Percoll density centrifugation (950:475) Samples were divided into aliquots to allow direct comparison of fresh and frozen spermatozoa from the same ejaculate Aliquots for cryopreservation were mixed with a commercial cryoprotectant and frozen by static phase vapour cooling before plunging into liquid nitrogen Thawing was carried out slowly at room temperature Sperm DNA integrity was determined using a modified alkaline single cell gel electrophoresis (comet) assay and sperm morphology analysed using the Tygerberg criteria DNA of semen and prepared spermatozoa from fertile men was found to be unaffected by cryopreservation In marked contrast, spermatozoa from infertile men were significantly damaged by freeze-thawing Cryopreservation had a detrimental effect on morphology of semen and prepared samples from fertile and infertile men
TL;DR: The semen analysis results of a fertile population were compared with those from a subfertile population, in order to establish normal cut-off values for the standard semen parameters with the aid of receiver operating characteristic (ROC) curve analysis.
Abstract: In this study, the semen analysis results of a fertile population were compared with those from a subfertile population, in order to establish normal cut-off values for the standard semen parameters with the aid of receiver operating characteristic (ROC) curve analysis. The fertile group comprised healthy males (n = 107) without any history of fertility problems, the partners of whom had had a spontaneous pregnancy within one year of unprotected intercourse and were pregnant at the time of the male's inclusion into the study. A total of 103 males from couples attending the infertility clinic, and with an initial sperm count of <20x10(6)/ml were recruited to form the subfertile population. The best discriminating parameter between the two populations was sperm morphology evaluated according to WHO criteria at a cut-off point of 31% normal spermatozoa. The other cut-off values were at 8% for the acrosome index, 45% for motility, and 4% normal spermatozoa for strict criteria. Recalculating the ROC curve cut-off values based on an assumed 50% prevalence of subfertility in an assisted reproductive setting, the cut-off points were reduced to 21% and 3% normal spermatozoa for WHO and strict criteria respectively. For motility, the new cut-off value was at 20% motile spermatozoa, for motility quality at 3.5 (on a scale of 1-6), the acrosome index at 3% normal acrosomes, and the teratozoospermia index at 2.09.
TL;DR: Equine spermatozoa generate ROS in vitro, possibly via a NADPH-oxidase reaction, and damaged and abnormal spermatozosa generate greater amounts of ROS that may contribute to reduced fertility or problems related to semen preservation.
Abstract: Objective—To characterize generation of reactive oxygen species (ROS) by equine spermatozoa. Sample Population—Multiple semen samples collected from 9 stallions. Procedure—Equine spermatozoa were separated from seminal plasma on a discontinuous polyvinylpyrrolidone (PVP)-coated silica gradient and resuspended in a modified Tyrode albumin-lactate-pyruvate medium. Amount of hydrogen peroxide (H2O2) generated was assayed by use of a 1-step fluorometric assay, using 10-acetyl-3,7-dihydroxyphenoxazine as a probe for detection of H2O2 in a microplate assay format. Concentration of H2O2 was determined by use of a fluorescence microplate reader. Results—Amount of H2O2 generated increased significantly with time and spermatozoa concentration for live and flash-frozen spermatozoa, and amount of H2O2 generated was significantly greater for flash-frozen than for live spermatozoa. Addition of the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) significantly increased generation of H2O2 by live and ...
TL;DR: An increased risk of sperm aneuploidy was not observed in infertile men with poor sperm motility or in those with a normal karyotype and normal semen parameters, and on chromosomal abnormalities in the spermatozoa of infertiles men who have normal somatic karyotypes.
Abstract: Reproductive difficulties are associated intimately with cytogenetic abnormalities. This article reviews multicolour fluorescence in situ hybridization studies on spermatozoa from men with constitutional chromosomal abnormalities and the consequences for spermatozoa, and on chromosomal abnormalities in the spermatozoa of infertile men who have normal somatic karyotypes. In 47,XYY men, the frequencies of 24,XY and 24,YY spermatozoa appear to be < or = 1%. Klinefelter (47,XXY) and mosaic Klinefelter patients had sperm aneuploidy frequencies of 2-25% and 1.5-7.0%, respectively. Robertsonian translocation carriers had 3-27% spermatozoa unbalanced for the chromosomes involved in the translocation, with a possible modest interchromosomal effect, but none of the increased frequencies of chromosomal disomy approached 1%. The frequency of chromosomally unbalanced spermatozoa in reciprocal translocations averages 50%, is strongly dependent on the chromosomes involved in the individual translocation, and may be slightly increased as a result of a small interchromosomal effect. Infertile men with a normal karyotype and low sperm concentration or certain types of morphologically abnormal spermatozoa have a significantly increased risk of producing aneuploid spermatozoa, particularly for the sex chromosomes. An increased risk of sperm aneuploidy was not observed in infertile men with poor sperm motility or in those with a normal karyotype and normal semen parameters.
TL;DR: Although calcium, magnesium, zinc, and copper play an essential role in spermatogenesis and fertility, the determination of these elements in blood and seminal plasma does not discriminate on the basis of fertility in this group of men.
TL;DR: Sperm frozen unprepared in seminal fluid appeared more resistant to freezing damage than frozen prepared sperm, suggesting freezing sperm in seminal plasma improves postthaw motility and DNA integrity.
TL;DR: Adding the enzyme scavenger, catalase, or a variety of lipid- and water-soluble antioxidants did not significantly improve the maintenance of motility during liquid semen storage at 5 degrees C.
TL;DR: The hypothesis that consistent interindividual variation in sperm freezability is genetically determined and may relate to processes that occur during spermatogenesis is supported.
Abstract: This study investigated two hypotheses: 1) that consistent between-boar variation in frozen semen quality exists and is genetically determined, and 2) that morphologically distinct subpopulations of spermatozoa exist within fresh boar ejaculates and that the incidence of these subpopulations is correlated with semen quality following cryopreservation. Five ejaculates were collected from each of 15 boars (5 boars from each of 3 breeds). An objective sperm morphology analyzer used Fourier shape descriptors to describe variation in the morphology of 300 spermatozoa per ejaculate before freezing. Semen was diluted into a commercial freezing buffer (700 mOsm/kg, 3% glycerol) and 5 straws (0.5 mL) per ejaculate were cryopreserved (to -5 degrees C at 6 degrees C/min, then -5 degrees C to -80 degrees C at 40 degrees C/min). Semen was assessed for percentage of motile cells and motility characteristics (with computer-aided sperm analysis), plasma membrane integrity (SYBR-14 positive), and acrosome integrity (fluorescein-labeled peanut agglutinin positive). Consistent between-boar variability was detected for post-thaw sperm motility (P < .01), membrane integrity (P < .01), acrosome integrity (P < .01), curvilinear velocity (P < .01), straight-line velocity (P < .05), beat cross-frequency (P < .05), and amplitude of lateral head displacement (P < .01). Three morphologically distinct subpopulations of spermatozoa, defined by Fourier descriptors, were detected. The proportion of these subpopulations within the fresh ejaculate correlated with semen quality assessments made following cryopreservation. These findings support the hypothesis that consistent interindividual variation in sperm freezability is genetically determined and may relate to processes that occur during spermatogenesis. Subsequent characterization of these genetic differences between "good" and "poor" freezers may ultimately identify biophysical components of the spermatozoa that are essential for successful cryopreservation.
TL;DR: Armed with a battery of tests, which evaluate many different sperm attributes, researchers should be able to more accurately estimate the fertilizing potential of semen samples.
TL;DR: The results demonstrate that the luminol-dependent chemiluminescence assay for ROS measurement is both accurate and reliable when the sperm concentration is greater than 1 x 10(5)/mL and the samples are analyzed within the first hour after specimen collection.
Abstract: A total of 28 donor semen samples were used to evaluate the characteristics of laboratory variability in measuring reactive oxygen species (ROS). The objectives of this study were to assess the interassay (same sample observed on different days by the same observers) variability; interdonor, intraobserver (replications of the same sample on the same day) variability; and interobserver (multiple observers on the same day with the same sample) variability of the luminol-dependent chemiluminescence assay and to establish an optimal semen age and sperm concentration. Semen samples were collected from 6 healthy donors for 108 measures of ROS. ROS levels were measured by the assay using luminol as the probe. An additional assessment measured the effect of time (age of the sample) on ROS production in 12 donor samples at 60, 120, 180, and 240 minutes after the specimen was produced. Last, to evaluate the effect of sperm concentration on ROS production, ROS levels were measured in 10 donor sample aliquots with sperm concentrations ranging from 1 to 120 x 10(6)/mL. In the controls, the mean ROS level was 0.218 x 10(6) counted photons per minute; the interassay variability standard deviation (SD) was 0.077. The interobserver SD was 0.002 for an interobserver reliability of 97.5% (coefficient of variation [CV] = 0.9%). The intraobserver (between replication) SD was 0.001 for an intraobserver reliability of 98.7% (CV = 0.5%). The interassay SD was 0.005 for an interassay reliability of 93.8% (CV = 2.0%). There was no statistically significant interobserver, intraobserver, or interassay variation (P > .80). ROS levels decreased significantly with time; a dramatic decline in ROS production was seen in the specimens that were more than 60 minutes old (P < .001). ROS values decreased by 31% at 120 minutes and 62% at 180 minutes compared with the 60-minute-old specimens. A linear relationship was seen between the ROS levels and sperm concentration in 8 of the 10 samples analyzed (R2 = .99). Our results demonstrate that the luminol-dependent chemiluminescence assay for ROS measurement is both accurate and reliable when the sperm concentration is greater than 1 x 10(5)/mL and the samples are analyzed within the first hour after specimen collection.
TL;DR: The results indicate that fluorometric assessment is in good agreement with other practiced procedures and can be performed with sufficient accuracy and may be a valuable complement for routinely practiced microscopic evaluation of sperm morphology of AI bull semen.
TL;DR: The nonreturn rate (NRR) and the number of live-born piglets were compatible with the requirements of artificial insemination for all boars included in this study and concentrations of IGF-I and IGF-II in seminal plasma were determined.
Abstract: This study was conducted to investigate the relationships between results of computer-assisted semen analysis (spermatozoal motility and sperm head morphometry) and fertility of boars. In addition, concentrations of insulin-like growth factor (IGF)-I and IGF-II in seminal plasma were determined. The nonreturn rate (NRR) and the number of live-born piglets were compatible with the requirements of artificial insemination for all boars included in this study. Semen samples of 12 boars (Pietrain; 3 ejaculates each) were evaluated for spermatozoal motility and sperm head dimensions using computer-assisted methods. Native semen samples were centrifuged, and seminal plasma was frozen at -20 degrees C until assayed for IGF-I and IGF-II by specific radioimmunoassays. Spermatozoa of boars with a higher NRR (>86%) had a significantly slower average velocity of motile spermatozoa when compared with that of boars with an NRR below 86%. High-fertility boars (NRR > 86%) had significantly smaller sperm heads than did boars with an NRR below 86%, and their sperm heads were less elongated. Substantial concentrations of IGF-I (8.4-22.2 ng/mL) and IGF-II (12.1-19.8 ng/mL) could be measured in porcine seminal plasma; however, there was no correlation between IGF levels and semen parameters or individual fertility.
TL;DR: Preliminary in vivo experiments support a suppressive role of seminal plasma in breeding-induced endometritis, and preliminary characterization of the immune-suppressive component in seminal plasma suggests it is one or more molecule(s) with a molecular weight between 50 and 100 kDa.
TL;DR: Results demonstrate that semen diluted in INRA96 extender and stored at 15 degrees C can be an alternative to semen dilution in milk-based extenders and storage at 4 degrees C for "poor cooler" stallions and can be as efficient at 15degree C as at 4degree C, for preserving sperm motility and fertility.
Journal Article•
TL;DR: The present review has been designed to update the recent developments on the function of seminal vesicles and their role on male fertility and it is indicated that the true corrected fructose level is a simple method for the assessment of the seminalvesicular function.
Abstract: The present review has been designed to update the recent developments on the function of seminal vesicles and their role on male fertility. It is indicated that the true corrected fructose level is a simple method for the assessment of the seminal vesicular function. Measurement of seminal fructose used universally as a marker of the seminal vesicle function is not an appropriate approach due to its inverse relationship with the sperm count. The true corrected fructose defined as [log. motile sperm concentration] multiplied by [seminal fructose concentration] has been shown to be a better marker of the seminal vesicle function. Seminal vesicular secretion is important for semen coagulation, sperm motility, and stability of sperm chromatin and suppression of the immune activity in the female reproductive tract. In conclusion, the function of seminal vesicle is important for fertility. Parameters as sperm motility, sperm chromatin stability, and immuno-protection may be changed in case of its hypofunction.
TL;DR: A new integrated approach including computer assisted sperm analysis (CASA), viability staining and fertilization was used to study the quality of cryodiluents used in fish sperm cryopreservation as mentioned in this paper.
TL;DR: Impaired function of cold-shocked ram spermatozoa freed from semen plasma could be prevented by addition of semen plasma proteins, resulting in higher maintained viability values, as well as the ability of Vitamin E to improve sperm survival.
TL;DR: It is concluded that the normal swim-up technique caused no more DNA damage to spermatozoa from normal semen samples than a direct swim- up technique that involved no centrifugation step.
Abstract: BACKGROUND: Swim-up techniques for sperm separation may have detrimental effects on sperm DNA. We wished to determine whether the normal swim-up method with centrifugation used in our laboratory, which involves a centrifugation step, was harmful to sperm compared with swim-up without centrifugation. METHODS: Semen samples were obtained from patients undergoing IVF or andrology assessment. An aliquot was removed for fixation and subsequent DNA fragmentation determination. The remaining sample was divided into two equal parts, which were subjected to swim-up either with (normal swim-up) or without (direct-swim-up) centrifugation. Semen analysis was performed both before and after swim-up. DNA fragmentation, in spermatozoa previously fixed in 4% paraformaldehyde, was assessed by the terminal transferase-mediated DNA end-labelling procedure (TUNEL). The percentage of spermatozoa with DNA damage after each swim-up technique was compared with that in the original semen sample. RESULTS: DNA damage was <5% in most samples. No significant change in DNA fragmentation was observed between the two swim-up procedures, although the ‘normal’ swim-up sample had significantly less DNA fragmentation than the pre-swim-up sample. CONCLUSIONS: We conclude that our normal swim-up technique caused no more DNA damage to spermatozoa from normal semen samples than a direct swim-up technique that involved no centrifugation step.
TL;DR: The data demonstrate that infertile men have significantly higher sperm DD compared with fertile men and that sperm DD exhibits a low coefficient of variation on repeated assessment, and suggest that spermDD has a relatively low degree of biologic variability.
TL;DR: It is suggested that the addition of seminal plasma can be beneficial to sperm viability when semen is diluted to low cell numbers/dose.