Another look at human sperm morphology.

STUDY QUESTION: Can a standardized assessment of abnormal human sperm morphology provide additional useful information by identifying men with more severe disturbances in different types of abnormalities? SUMMARY ANSWER: Definition-based categorization of sperm head, midpiece and tail defects has shown how differently these abnormalities are distributed in fertile men and other groups of men, thus providing high and low thresholds, a starting point for diagnosis or research purposes. WHAT IS KNOWN ALREADY: Several recent studies have reported indisputable genetic origins for various sperm defects. A few studies have also identified associations between environmental factors and low percentages of morphologically normal spermatozoa. Nevertheless, with the exception of rare situations in which the vast majority of spermatozoa have specific, easily characterized defects, such as 'globozoospermia', little attention has been paid to the description and precise quantification of human sperm abnormalities. The lack of standardization in the phenotyping of sperm morphological defects by conventional microscopy is a limiting factor for diagnosis and for intra- or inter-observer or centre consistency in studies investigating the causal factors and possible functional consequences of the abnormalities detected. There are currently no baseline data for abnormalities of sperm morphology based on a standardized classification, in the general population, among fertile or other groups of men. STUDY DESIGN, SIZE, DURATION: This study is based on detailed sperm abnormality datasets acquired by a standardized classification method, from several groups of men, over the same 5-year period. PARTICIPANTS/MATERIALS, SETTING, METHODS: We studied cross-sectional data from fertile men (n = 926), male partners from infertile couples (n = 1747) and testicular cancer patients (n = 239). We used a standardized classification to analyse Shorr-stained slides, taking into account all the abnormalities encountered. MAIN RESULTS AND THE ROLE OF CHANCE: Most sperm defects were significantly more frequent in infertile than in fertile men, with 20-30% of infertile men having frequencies of abnormalities above the 95th percentile in fertile men for 9 out of the 15 categories of abnormalities. Interestingly, several head abnormalities were significantly more frequent in patients with testicular cancer than in infertile men, highlighting the particular impact of this condition on sperm morphogenesis. We used the 95th percentile in fertile men as the lower threshold and the 99th percentile in infertile men as an extreme upper threshold, for the classification of morphological abnormality frequencies into three levels: low, intermediate and high. The assessment of several semen samples, with or without a genetic background, for abnormal sperm morphology, based on the percentage of normal spermatozoa, a teratozoospermia index, and the detailed profile of abnormalities categorized according to the three levels proposed, has highlighted the value of detailed phenotyping for diagnosis and research purposes. LIMITATIONS, REASONS FOR CAUTION: The thresholds proposed for the various categories of sperm abnormality should be considered relative rather than absolute, owing to the known sampling error related to the limited number of spermatozoa assessed per sample, or when studying the general population or populations from regions other than Western Europe. The standardized assessment of abnormal sperm morphology requires time and experience. We therefore suggest that this assessment is carried out during a first andrological check-up or for epidemiological or research studies, rather than in the routine management of infertile couples for assisted reproductive technologies. WIDER IMPLICATIONS OF THE FINDINGS: The study design used for the fertile group of men was similar to that previously used for the WHO reference values, providing a rationale for considering the 95th percentile in fertile men as the level below which abnormalities may be considered to occur at a frequency representing random background variations of a normal spermiogenesis process. The crude frequencies obtained, and the three levels of abnormality frequency proposed for each standardized category of sperm defect, provide baseline data useful for diagnosis and a starting point for future studies aiming to identify associations with genetic or environmental factors. STUDY FUNDING/COMPETING INTERESTS: Part of this study was supported by contract BMH4-CT96-0314 from the European Union. The authors have no competing interests to declare.

Impaired sperm motility in HIV-infected men: an unexpected adverse effect of efavirenz?

STUDY QUESTION: Are antiretroviral therapies associated with semen alterations in HIV-infected men? SUMMARY ANSWER: Antiretroviral regimens that included the non-nucleosidic reverse transcriptase inhibitor efavirenz were associated with a significant impairment of sperm motility, whereas regimens without efavirenz were not associated with significant semen changes. WHAT IS KNOWN ALREADY: Semen alterations including decreased ejaculate volume and sperm motility have been reported in HIV-infected men. The hypothesis ascribing reduced sperm motility to damages induced in sperm mitochondria by nucleosidic (or nucleotidic) reverse transcriptase inhibitors (NRTIs) has not been confirmed in HIV-infected patients and the effects of antiretroviral treatments on semen parameters remain unclear. STUDY DESIGN, SIZE, DURATION: This case-control study compared semen characteristics across 378 HIV-1 infected patients receiving different antiretroviral regimens or never treated by antiretroviral drugs, in whom an initial semen analysis was done between 2001 and 2007. PARTICIPANTS/MATERIALS, SETTING, METHODS: The patients were partners from serodiscordant couples requesting medical assistance to procreate safely. Their status with regard to antiretroviral therapy at the time of semen analysis was categorized as follows: 1/ never treated patients (n = 66); 2/ patients receiving NRTIs only (n = 49); 3/ patients receiving a NRTIs + protease inhibitor (PI) regimen (n = 144); 4/ patients receiving a NRTIs + non-nucleosidic reverse transcriptase inhibitor (NNRTI) regimen (n = 119). Semen parameters were assessed through standard semen analysis. Additional analyses included measurement of sperm motion parameters using computer-assisted semen analysis, seminal bacteriological analysis, seminal biochemical markers and testosterone plasmatic levels. All analyses were performed in the Cochin academic hospital. The data were analyzed through multivariate analysis. MAIN RESULTS AND THE ROLE OF CHANCE: Sperm motility was the only semen parameter which significantly varied according to treatment status. The median percentage of rapid spermatozoa was 5% in the group of patients receiving a regimen including efavirenz versus 20% in the other groups (P < 0.0001). Accordingly, sperm velocity was reduced by about 30% in this group (P < 0.0001). The role of chance was minimized by the strict definition and the size of the study population, which included a large enough group of never treated patients, the controlled conditions of semen collection and analysis, the multivariate analysis, the specificity and the high significance level of the observed differences. LIMITATIONS, REASONS FOR CAUTION: The design of the study did not allow demonstrating a causal link between exposure to efavirenz and sperm motility. WIDER IMPLICATIONS OF THE FINDINGS: As efavirenz is widely used in current antiretroviral therapy, these findings may concern many HIV-infected men wishing to have children. This justifies further assessment of the consequences on fertility of the exposure to efavirenz. Moreover, the possibility of common cellular impacts underlying adverse effects of efavirenz in sperm cells and neurons deserved investigation. STUDY FUNDING/COMPETING INTERESTS: No external funding was used for this study. None of the authors has any conflict of interest to declare.

[Requests for assisted reproduction formulated by same-sex couples consulting physicians in France]. / Demandes d'aide à la procréation formulées par les couples de même sexe auprès de médecins en France.

BACKGROUND, MATERIAL AND METHODS: In order to determine the characteristic features of requests for assisted reproduction formulated by same-sex couples consulting physicians in France, we conducted a study in collaboration with professional organizations, general practitioners, gynecologists and obstetricians who distributed an email questionnaire among their recruitment. RESULTS: In our sample, 191 physicians (71% of responders) reported that 1040 homosexual couples expressed desire to become parents in 2011-2012. Nearly all of the physicians (94%) reported that the couples sought assistance before participating in an assisted reproduction technology (ART) program in a foreign country, but 35% reported that advice was solicited concerning natural reproduction and 48.5% reported requests for advice concerning inseminations performed by the woman herself. Most of the physicians responded to all or part of the requests and 61% of those who had been consulted reported they had directly participated in preparing an ART program in a foreign country. Among the 270 physicians who participated in this study, 162 (60%) believed that ART should be assessable to homosexual couples in France, but less than half of them were in favor of reimbursement by the national health insurance fund. DISCUSSION: Although biased and non-representative, this study shows that assisted reproduction, with or without medical intervention, is a real-life phenomenon for many homosexual couples, and for many physicians, even before same-sex marriage became legal.

Cardiovascular findings in women suffering from Turner syndrome requesting oocyte donation.

BACKGROUND: Through oocyte donation (OD), women with Turner syndrome (TS) may achieve motherhood. However, this population has a high prevalence of cardiac malformations and carry a risk for aortic dissection that is increased by pregnancy. Until recently, the necessity for a specialized cardiac evaluation before pregnancy was underestimated as was the need for follow-up through adulthood. The aim of this study was to evaluate the follow-up (mainly cardiovascular) of women with TS requesting OD. METHODS: Disease monitoring since diagnosis and prior cardiac evaluations conducted out of our centre were assessed in 25 women with TS who requested OD. New cardiac evaluations using echocardiography and magnetic resonance imaging were performed by our specialized cardiologist in 18 of these patients. RESULTS: We observed that the medical follow-up of women with TS was often deficient throughout adulthood. Most of the prior cardiac evaluations performed by cardiologists not accustomed to women with TS, either before (n = 8) or when starting OD (n = 12), were considered normal. However, when revaluated by a cardiologist who is familiar with TS, seven women were diagnosed with a bicuspid aortic valve and thus excluded from OD. In addition, when appropriate screening was conducted by our referent cardiologist before OD no cardiac complication was observed during pregnancy or delivery. CONCLUSIONS: Careful follow-up, including cardiac evaluation, should be recommended for women diagnosed with TS, before and after puberty. Moreover, assessment of cardiovascular parameters by a cardiologist familiar with TS should be routinely repeated before undertaking OD.

[Parental imprinting related to Assisted Reproductive Technologies]. / Empreinte parentale et Assistance médicale à la procréation.

Until the introduction of Assisted Reproductive Technologies (ART), many studies were conducted in order to evaluate their impact upon the children's health born in such a way. The epigenetic-risk notion was invoked and a link between ART and diseases associated with imprinting alterations was suggested with different examples, such as Beckwith-Wiedemann syndrome (BWS), Angelman syndrome (AS) and Silver-Russell syndrome (SRS). The epigenetic "life cycle" of imprinting (germline erasure, germline establishment, and somatic maintenance) concerns all the phases from gametogenesis, gamete maturation, fertilization, to early embryo development and appears particularly vulnerable to perturbations induced by superovulation, in vitro fertilization, embryo culture and embryo transfer. The studies, performed in model animal, provide a basis of the understanding of imprinting alterations induced by the ART and clinically useful information in order to improve the ART.

Glycol ethers and semen quality: a cross-sectional study among male workers in the Paris Municipality.

OBJECTIVES: Apparent increases in human male reproductive disorders, including low sperm production, may have occurred because of increased chemical exposure. Various glycol ether-based solvents have pronounced adverse effects on sperm production and male fertility in laboratory animals. The authors investigated the effects of past and current exposure to glycol ether-containing products on semen quality and reproductive hormones among men employed by the Paris Municipality. METHODS: Between 2000 and 2001 the authors recruited 109 men who gave semen, blood and urine samples and underwent an andrological examination. Information on lifestyle, occupation, exposure and medical history was obtained by interview. According to their job and chemical products used during the period 1990-2000, men were classified as either occupationally exposed or non-exposed. Current exposure levels to glycol ethers at the time of the study were evaluated by biological monitoring of six urinary metabolites. RESULTS: Previous exposure to glycol ethers was associated with an increased risk for sperm concentration, for rapid progressive motility and for morphologically normal sperm below the World Health Organization semen reference values. No effect of previous glycol ether exposure on hormones levels was observed. By contrast, current glycol ether exposure levels were low and not correlated with either seminal quality or hormone levels. CONCLUSIONS: This study suggests that most glycol ethers currently used do not impact on human semen characteristics. Those that were more prevalent from the 1960s until recently may have long lasting negative effects on human semen quality.

The epigenetic imprinting defect of patients with Beckwith-Wiedemann syndrome born after assisted reproductive technology is not restricted to the 11p15 region.

BACKGROUND: Genomic imprinting refers to an epigenetic marking resulting in monoallelic gene expression and has a critical role in fetal development. Various imprinting diseases have recently been reported in humans and animals born after the use of assisted reproductive technology (ART). All the epimutations implicated involve a loss of methylation of the maternal allele (demethylation of KvDMR1/KCNQ1OT1 in Beckwith-Wiedemann syndrome (BWS), demethylation of SNRPN in Angelman syndrome and demethylation of DMR2/IGF2R in large offspring syndrome), suggesting that ART impairs the acquisition or maintenance of methylation marks on maternal imprinted genes. However, it is unknown whether this epigenetic imprinting error is random or restricted to a specific imprinted domain. AIM: To analyse the methylation status of various imprinted genes (IGF2R gene at 6q26, PEG1/MEST at 7q32, KCNQ1OT1 and H19 at 11p15.5, and SNRPN at 15q11-13) in 40 patients with BWS showing a loss of methylation at KCNQ1OT1 (11 patients with BWS born after the use of ART and 29 patients with BWS conceived naturally). RESULTS: 3 of the 11 (27%) patients conceived using ART and 7 of the 29 (24%) patients conceived normally displayed an abnormal methylation at a locus other than KCNQ1OT1. CONCLUSIONS: Some patients with BWS show abnormal methylation at loci other than the 11p15 region, and the involvement of other loci is not restricted to patients with BWS born after ART was used. Moreover, the mosaic distribution of epimutations suggests that imprinting is lost after fertilisation owing to a failure to maintain methylation marks during pre-implantation development.

Bisulfite genomic sequencing of microdissected cells.

Mapping of methylation patterns in CpG islands has become an important tool for understanding tissue-specific gene expression in both normal and pathological situations. However, the inherent cellular heterogeneity of any given tissues can affect the outcome and interpretation of molecular studies. In order to analyse genomic DNA methylation on a pure cell population from tissue sample, we have developed a simple technique of single-cell microdissection from cryostat sections which can be combined with bisulfite-mediated sequencing of 5-methylcytosine. We report here our results on the methylation status of the androgen receptor gene studied by bisulfite genomic sequencing on purified cells isolated from human testis.

Geographic variations in probability of pregnancy in four cities of France.

BACKGROUND: Several studies have described geographic variations in human fecundability, but this phenomenon has almost exclusively been studied at an international level rather than within a given country. Our aim was to describe geographic variations in fecundability, the monthly probability of pregnancy, between four cities of France. METHODS: We conducted a cross-sectional study in four French maternity units from Toulouse, Rennes, Lyons and Paris, among partners of pregnant women. Women were asked about the time to pregnancy (TTP) of their current pregnancy. TTP was analysed with a discrete Cox model allowing to estimate fecundability ratios (FR). RESULTS: Time to pregnancy was defined for 894 couples. There was no strong evidence of heterogeneity in fecundability between the four compared cities (p=0.05 without adjustment and p=0.25 after adjustment for behavioural and medical factors). The highest fecundability was observed in Rennes and the lowest in Toulouse (fecundability ratio (FR)=1.28, 95% CI: 1.01-1.63). Differences in fecundability were smaller between the other cities. CONCLUSION: We highlighted a possibly slightly higher fecundability in Rennes compared to Toulouse. Possible explanations for this finding are discussed. We note that the finding is consistent with previous observations indicating a higher sperm concentration among semen donors in Rennes than in Toulouse.

Age and male fertility: biological factors.

Although the effect of maternal age on fertility is well known, whether paternal age also affects fertility remains unclear. If there is an effect, the biological causes and consequences, especially for the offspring, are unclear. We present a short review of the data and various studies on this subject. Data on young men or fathers are not considered here. Advanced male age has been associated with: Increased time-to-pregnancy (TTP) and subfecundity; low semen volume, total sperm count, sperm motility and normal sperm morphology; gradual modification of testicular vascularisation and regular decrease in the number of Sertoli and Leydig cells, with an associated decrease in serum testosterone. There are wide interindividual variations of these modifications, with some elderly men having a reproductive function similar to young men. Whether there is an increase in levels of qualitative and or quantitative alterations of the sperm chromosomes with advancing age remains controversial. It can be suggested that there is an increased risk of developmental defects in the offspring of older men, as the spontaneous mutation rate is closely related to the age of the man. An increasing rate of miscarriages has been related to older fathers and several studies suggest older fathers are at the origin of several diseases in the new-born. In conclusion, further studies are needed due to the increasing number of older men wishing to become a father.

Auto-antibodies to human sperm basic nuclear proteins in infertile and vasectomized men: characterization of antigens and epitopes recognized by antibodies.

The sera of vasectomized men and of patients with immune infertility were used to study the antigens and epitopes of sperm nuclear proteins that bind antibodies in these sera. No reaction with sperm histones was observed except for one serum. P1, P2 protamines and pro-P2 protamines were recognized by auto-antibodies. Studies with peptides derived from P1 and P2 protamines and with mammalian protamines related to HP1 showed that antibodies are mainly specific for a folded protamine molecule, more especially antibodies from vasectomized men. These results disagree with the random coil model proposed for protamines by several previous works. A cross-reactivity between P1 and P2 protamines was observed only for the whole molecules and not for peptides derived from them. This observation suggests that the two classes of protamines, different in sequence, may have a similar folding and thereby may be functionally equivalent.

Detection and quantification of HIV-1 in semen: identification of a subpopulation of men at high potential risk of viral sexual transmission.

BACKGROUND: To assess HIV burden in both acellular and cellular fractions of semen in men with different levels of blood plasma HIV RNA by a cross-sectional study. PATIENTS: Fifty-two HIV-1-seropositive men (21 receiving antiretroviral therapy) with CD4 cell counts ranging from 1 to 1170 x 10(6)/l. METHODS: Semen was separated into seminal plasma and fractions enriched in motile spermatozoa or non-spermatozoal cells. HIV RNA was quantified by the HIV-Monitor technique (Roche) in blood plasma, seminal plasma and spermatozoa fractions. HIV DNA or infectious virions in cellular fractions were detected by either PCR or qualitative viral culture. RESULTS: HIV RNA was detected in 86.5% of seminal plasma specimens and in 14.6% of spermatozoa fractions; HIV DNA was detected in 57.1% of non-spermatozoal cell fractions. HIV RNA levels in blood plasma and seminal plasma were correlated (r5 = 0.56, P < 0.0001, Spearman's rank test). A majority of men had lower levels in seminal plasma than in blood plasma: one-third had HIV-positive seminal cell fractions. However, 20 men (38.5%) with HIV RNA levels in seminal plasma (median: 4.65 log10 copies/ml) comparable to or higher than those in blood plasma had all HIV-positive non-spermatozoal cells or spermatozoa fractions with a high frequency of positive cultures. CONCLUSION: A high frequency of men had detectable HIV in semen. We identified a subpopulation demonstrating high levels of HIV RNA in seminal plasma, comparable to or higher than those in blood plasma, frequently associated with a substantial viral shedding in seminal cells, raising the possibility of viral production within the genital tract and suggesting heterogeneity in the potential of HIV sexual transmission among infected men.

DHPLC-based method for DNA methylation analysis of differential methylated regions from imprinted genes.

The bisulfite genomic sequencing method is one of the most widely used techniques for methylation analysis in heterogeneous unbiased PCR, amplifying for both methylated and unmethylated alleles simultaneously. However, it requires labor-intensive and time-consuming cloning and sequencing steps. In the current study, we used a denaturing high-performance liquid chromatography (DHPLC) procedure in a complementary way with the bisulfite genomic sequencing to analyze the methylation of differentially methylated regions (DMRs) of imprinted genes. We showed reliable and reproducible results in distinguishing overall methylation profiles of DMRs regions of human SNRPN, H19, MEST/PEG1, LIT1, IGF2, TSSC5, WT1 antisense, and mouse H19, Mest/Peg1, Igf2R imprinted genes. These DHPLC profiles were in accordance with bisulfite genomic sequencing data and may serve as a type of "fingerprint," revealing the overall methylation status of DMRs associated with sample heterogeneity. We conclude that DHPLC analysis could be used to increase the throughput efficiency of methylation pattern analysis of imprinted genes after the bisulfite conversion of genomic DNA and unbiased PCR amplification.

Flow cytometric sorting of living, highly motile human spermatozoa based on evaluation of their mitochondrial activity.

We investigated the applicability of flow cytometric (FCM) sorting to select, with no deleterious effects, fractions of living, highly motile spermatozoa after staining with rhodamine 123 (Rh123) and propidium iodide (PI) for assessment of their mitochondrial activity and viability, respectively. Sperm cells were subjected to FCM sorting according to their Rh123 fluorescence intensity, and computer-aided sperm analysis (CASA) for percentage motility and movement characteristic measurements was carried out on the entire sperm populations and on the Rh123-positive (Rh123+) sorted fractions. A first experiment on five sperm samples from fertile donors pre-selected by either swim-up or simplified Percoll gradient indicated no detrimental effect of the FCM sorting procedure because: (a) the numbers of Rh123+ motile sperm were not decreased by FCM sorting; (b) data on the sorted fractions showed a tendency (not significant) for an increase in movement parameters rather than a drop; and (c) a significant decrease in the percentage of PI-positive (PI+) sperm (13% vs 3%; p < 0.05) was measured. A second experiment was performed on sperm samples from four patients, only washed and re-suspended in B2 medium. This demonstrated a significant increase in some characteristics of movement quality related to a substantial and selective immobilization of the less motile sperm. The significant drop in the percentage of PI+ sperm after FCM sorting (p < 0.01) was less pronounced than after FCM sorting of pre-selected sperm (12% vs 3%, respectively), indicating a lethal effect of FCM sorting on a small proportion of presumably moribund sperm. These preliminary data indicate a differential effect of FCM sorting on sperm according to their function characteristics and suggest the potential importance of these methods for the characterization in vitro of sperm subpopulations on the basis of functional criteria.

Male reproductive health and environmental xenoestrogens.

Male reproductive health has deteriorated in many countries during the last few decades. In the 1990s, declining semen quality has been reported from Belgium, Denmark, France, and Great Britain. The incidence of testicular cancer has increased during the same time incidences of hypospadias and cryptorchidism also appear to be increasing. Similar reproductive problems occur in many wildlife species. There are marked geographic differences in the prevalence of male reproductive disorders. While the reasons for these differences are currently unknown, both clinical and laboratory research suggest that the adverse changes may be inter-related and have a common origin in fetal life or childhood. Exposure of the male fetus to supranormal levels of estrogens, such as diethlylstilbestrol, can result in the above-mentioned reproductive defects. The growing number of reports demonstrating that common environmental contaminants and natural factors possess estrogenic activity presents the working hypothesis that the adverse trends in male reproductive health may be, at least in part, associated with exposure to estrogenic or other hormonally active (e.g., antiandrogenic) environmental chemicals during fetal and childhood development. An extensive research program is needed to understand the extent of the problem, its underlying etiology, and the development of a strategy for prevention and intervention.

Semen quality and male reproductive health: the controversy about human sperm concentration decline.

Concern about the effect of environmental changes on male reproductive health has grown in recent years to become a major preoccupation in some developed countries. A possible decline in human sperm concentration was suggested in the early seventies following studies in the US. In 1992 a meta-analysis of 61 articles published by Carlsen et al. concluded that the mean sperm count of healthy men had declined by 1% per year over the previous 50 years. From 1995 and onwards, some retrospective, longitudinal analyses of the sperm count of fertile or infertile men contradicted this while others did not. The demonstration of a geographical variation in sperm concentration, between and within countries or regions, appears to be less controversial. The amplitude of the difference observed cannot only be explained by methodological or confounding factors, and must to some extent be attributed to ethnic, genetic or environmental factors. As many of the published studies suffer from imprecision regarding the description of population characteristics and confounding factors, and were not designed with controlled and standardised methodology, the debate remains open. Prospective studies in well-defined cohorts of men in various populations are required to evaluate the potential effect of external factors on male reproductive health. These studies should not be limited to the analysis of sperm concentration, as this may not be the best biomarker of testis function and human fertility.

Detection of HIV-1 in seminal plasma and seminal cells of HIV-1 seropositive men.

It is of critical importance to precisely understand the modalities of HIV presence in semen, especially with regard to procreation. In this study, paired blood and semen samples from 31 human immunodeficiency virus type 1 (HIV-1)-positive men were assessed for cell-free HIV-RNA load in blood plasma (BP) and seminal plasma (SP), and for detection of HIV by culture, PCR and RT-PCR in semen cellular fractions separated by centrifugation on Percoll gradient. HIV-RNA was detected in 94% of BP and 84% of SP samples. For 11 men (35%), HIV-RNA load in SP was equal or superior to that observed in blood. HIV-DNA presence was demonstrated (either by PCR or culture positivity) in 39% of the non-spermatozoal cells (NSC)-enriched fractions, and in one Percoll-selected sperm pellet. HIV-RNA was detected in 17% (4/23) of the sperm pellets. This positivity was associated with an HIV-RNA load in SP equal or superior to the HIV-RNA load in blood, a high rate of HIV-DNA detection in the NSC fraction, and a low CD4+ cell count. In such conditions, a significant viral production inside the genital tract is more likely to be present, and a close association between HIV and gametes might occur. Assisted procreation with selected spermatozoa should be preceded by accurate assessments of viral presence in blood, SP and semen cellular fractions.

Evolution of the properties of semen immediately following vasectomy.

Semen parameters were analyzed in a series of 76 men pre- and postvasectomy. The mean volume decrease was 0.66 ml but it was 0.5 ml or more for only 53% of subjects. A decrease in the number of spermatozoa was correlated primarily with the number of ejaculations. In nearly all cases the total number of spermatozoa contained in all semen samples examined after vasectomy was clearly lower than the average number contained in only one ejaculation prior to vasectomy. Motile spermatozoa were never observed after the 15th day following vasectomy. The reappearance of motile spermatozoa after that time was an almost certain sign of a defect in the vas block or of recanalization of the vas deferens.

Sliding spermatozoa: a dyskinesia responsible for human infertility?

Microcinematographic analysis at 50 frames/second of motile spermatozoa from four sterile men, which were permanently unable to penetrate the cervical mucus or migrate through it was performed at ambient temperature. In all cases, we found the same abnormal pattern of movement, characterized by a very small amplitude of the periodic lateral displacement of the head and abnormal displacement of the wave along the flagellum. The results assessed the importance of normal sperm flagellar dynamics for fertility.