Computer-assisted measurement of sperm swimming speed in human semen: correlation of results with in vitro fertilization assays

Factors affecting the success of laparoscopic artificial insemination in sheep

Successful artificial breeding underpins rapid genetic and production gains in animal agriculture. In sheep, artificial insemination with frozen semen is performed via intrauterine laparoscopy as frozen-thawed spermatozoa do not traverse the cervix in sufficient numbers for high fertility and transcervical insemination is anatomically impossible in most ewes. Historically, laparoscopic artificial insemination has always been considered reasonably successful, but recent anecdotal reports of poor fertility place it at risk of warning adoption. Understanding the male, female and environmental factors that influence the fertility of sheep is warranted if the success of artificial insemination is to be improved and genetic progress maximised for the sheep industry. This review details the current practice of laparoscopic AI in sheep. It explores the effects of semen quantity and quality, the ewe, her preparation, and environmental conditions, on the fertility obtained following laparoscopic artificial insemination.

Effect of chronic sleep deprivation on acrosomal integrity and functional parameters of murine sperm

OBJECTIVE

To evaluate the effect of chronic sleep deprivation on sperm function quality in mice.

DESIGN

Experimental study.

SETTING

Not applicable.

ANIMALS

Spermatozoa from twenty-four 10-week-old C57BL/6J male mice.

INTERVENTION(S)

The sleep deprivation group underwent gentle handling for 6 hours for 5 consecutive days. The mice in the sleep recovery group were allowed to sleep during the 24-hour period after the sleep deprivation protocol.

MAIN OUTCOME MEASURE(S)

After euthanasia, the spermatozoa were collected for analysis. Sperm motility was evaluated using computer-assisted sperm analyzer. Intracellular superoxide anion (O₂^-) activity, acrosome integrity, mitochondrial activity, and DNA fragmentation assays were conducted afterward.

RESULT(S)

Sleep deprivation and sleep recovery groups presented a lower percentage of spermatozoa with an intact acrosome, compared with the respective control groups. Regarding DNA fragmentation, a decreased proportion of spermatozoa with Comet I class intact DNA was observed in the sleep recovery group, compared with the recovery control group. Beat cross frequency was increased in the sleep recovery group.

CONCLUSION(S)

Sleep deprivation can reduce sperm quality, impairing acrosome integrity. Sleep recovery decreased DNA integrity and increased beat cross frequency.

Predicting fertility from sperm motility landscapes

Understanding the organisational principles of sperm motility has both evolutionary and applied impact. The emergence of computer aided systems in this field came with the promise of automated quantification and classification, potentially improving our understanding of the determinants of reproductive success. Yet, nowadays the relationship between sperm variability and fertility remains unclear. Here, we characterize pig sperm motility using t-SNE, an embedding method adequate to study behavioural variability. T-SNE reveals a hierarchical organization of sperm motility across ejaculates and individuals, enabling accurate fertility predictions by means of Bayesian logistic regression. Our results show that sperm motility features, like high-speed and straight-lined motion, correlate positively with fertility and are more relevant than other sources of variability. We propose the combined use of embedding methods with Bayesian inference frameworks in order to achieve a better understanding of the relationship between fertility and sperm motility in animals, including humans.

Dimension reduction methods on porcine sperm motility landscapes reveal heterogeneity and hierarchy in sperm movement behavior and show high-speed and straight-lined motion as predictive features of fertility.

Prediction of Sperm Progression in Three Dimensions Using Rapid Optical Imaging and Dynamic Mechanical Modeling

We present a multidisciplinary approach for predicting how sperm cells with various morphologies swim in three-dimensions (3D), from milliseconds to much longer time scales at spatial resolutions of less than half a micron. We created the sperm 3D geometry and built a numerical mechanical model using the experimentally acquired dynamic 3D refractive-index profiles of sperm cells swimming in vitro as imaged by high-resolution optical diffraction tomography. By controlling parameters in the model, such as the size and shape of the sperm head and tail, we can then predict how different sperm cells, normal or abnormal, would swim in 3D, in the short or long term. We quantified various 3D structural factor effects on the sperm long-term motility. We found that some abnormal sperm cells swim faster than normal sperm cells, in contrast to the commonly used sperm selection assumption during in vitro fertilization (IVF), according to which sperm cells should mainly be chosen based on their progressive motion. We thus establish a new tool for sperm analysis and male-infertility diagnosis, as well as sperm selection criteria for fertility treatments.

Extended semen examinations in the sixth edition of the World Health Organization manual on semen analysis: contributing to the understanding of the function of the male reproductive system

In the sixth edition of the World Health Organization manual for the examination and processing of human semen, extended examination methods to provide key diagnostics in the investigation of the male reproductive system function are elaborated. These go beyond the basic analysis of semen and may be useful in more specifically guiding the clinical characterization of fertile or infertile men. Among the extended examinations included in the chapter, the use of multiparametric scoring for sperm morphological defects, sperm DNA fragmentation, and the roles for computer-assisted analysis of sperm or semen are arguably those that will be the most widely used and may also cause the most debate.

Deep Learning Based Evaluation of Spermatozoid Motility for Artificial Insemination

We propose a deep learning method based on the Region Based Convolutional Neural Networks (R-CNN) architecture for the evaluation of sperm head motility in human semen videos. The neural network performs the segmentation of sperm heads, while the proposed central coordinate tracking algorithm allows us to calculate the movement speed of sperm heads. We have achieved 91.77% (95% CI, 91.11-92.43%) accuracy of sperm head detection on the VISEM (A Multimodal Video Dataset of Human Spermatozoa) sperm sample video dataset. The mean absolute error (MAE) of sperm head vitality prediction was 2.92 (95% CI, 2.46-3.37), while the Pearson correlation between actual and predicted sperm head vitality was 0.969. The results of the experiments presented below will show the applicability of the proposed method to be used in automated artificial insemination workflow.

Low-density lipoproteins protect sperm during cryopreservation in buffalo: Unraveling mechanism of action

This study was carried out to reveal factors and the mechanism of action by which low-density lipoproteins (LDLs) protect sperm better than egg yolk (EY) during cryopreservation. We extracted LDL from EY and compared the amount of calcium, progesterone, and antioxidants in EY and LDL. We found a very high concentration of progesterone (1423.95 vs. 10.46 ng/ml) and calcium (29.19 vs. 0.47 mM) in EY as compared with LDL. Antioxidant assays like DPPH (2,2-diphenyl-1-picrylhydrazyl) and the ferric reducing antioxidants power assay revealed that the LDL extender had almost double ability to lose hydrogen than the EY extender. For sperm cryopreservation, 20 ejaculates from four Murrah buffalo bulls were collected. Each ejaculate was divided into four aliquots and extended in 10%, 12%, and 14% LDL (w/v) and EY-based extenders, followed by cryopreservation. The LDL-based extender prevented excessive cholesterol efflux, and its high content of antioxidants minimized reactive oxygen species generated during cryopreservation, resulting in a functional CatSper channel. The EY-based extender promoted excess cholesterol efflux due to the presence of high-density lipoprotein, resulting in a compromised CatSper channel. High intracellular calcium in a cryopreserved sperm in the EY group as compared with the LDL group indicates that progesterone present in EY activates the CatSper channel, resulting in a heavy calcium influx into the sperm. The greater tyrosine phosphorylation and increased number of F-pattern in the sperm cryopreserved in the EY extender indicate that high intracellular calcium triggers more capacitation-like changes in the sperm cryopreserved in EY than LDL extender. In conclusion, we demonstrated the new facts and understandings about LDL and EY for semen cryopreservation.

Rapid sperm capture: high-throughput flagellar waveform analysis

STUDY QUESTION

Can flagellar analyses be scaled up to provide automated tracking of motile sperm, and does knowledge of the flagellar waveform provide new insight not provided by routine head tracking?

SUMMARY ANSWER

High-throughput flagellar waveform tracking and analysis enable measurement of experimentally intractable quantities such as energy dissipation, disturbance of the surrounding medium and viscous stresses, which are not possible by tracking the sperm head alone.

WHAT IS KNOWN ALREADY

The clinical gold standard for sperm motility analysis comprises a manual analysis by a trained professional, with existing automated sperm diagnostics [computer-aided sperm analysis (CASA)] relying on tracking the sperm head and extrapolating measures. It is not currently possible with either of these approaches to track the sperm flagellar waveform for large numbers of cells in order to unlock the potential wealth of information enclosed within.

STUDY DESIGN, SIZE, DURATION

The software tool in this manuscript has been developed to enable high-throughput, repeatable, accurate and verifiable analysis of the sperm flagellar beat.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Using the software tool [Flagellar Analysis and Sperm Tracking (FAST)] described in this manuscript, we have analysed 176 experimental microscopy videos and have tracked the head and flagellum of 205 progressive cells in diluted semen (DSM), 119 progressive cells in a high-viscosity medium (HVM) and 42 stuck cells in a low-viscosity medium. Unscreened donors were recruited at Birmingham Women's and Children's NHS Foundation Trust after giving informed consent.

MAIN RESULTS AND THE ROLE OF CHANCE

We describe fully automated tracking and analysis of flagellar movement for large cell numbers. The analysis is demonstrated on freely motile cells in low- and high-viscosity fluids and validated on published data of tethered cells undergoing pharmacological hyperactivation. Direct analysis of the flagellar beat reveals that the CASA measure 'beat cross frequency' does not measure beat frequency; attempting to fit a straight line between the two measures gives ${\mathrm{R}}^2$ values of 0.042 and 0.00054 for cells in DSM and HVM, respectively. A new measurement, track centroid speed, is validated as an accurate differentiator of progressive motility. Coupled with fluid mechanics codes, waveform data enable extraction of experimentally intractable quantities such as energy dissipation, disturbance of the surrounding medium and viscous stresses. We provide a powerful and accessible research tool, enabling connection of the mechanical activity of the sperm to its motility and effect on its environment.

LARGE SCALE DATA

The FAST software package and all documentation can be downloaded from www.flagellarCapture.com.

LIMITATIONS, REASONS FOR CAUTION

The FAST software package has only been tested for use with negative phase contrast microscopy. Other imaging modalities, with bright cells on a dark background, have not been tested but may work. FAST is not designed to analyse raw semen; it is specifically for precise analysis of flagellar kinematics, as that is the promising area for computer use. Flagellar capture will always require that cells are at a dilution where their paths do not frequently cross.

WIDER IMPLICATIONS OF THE FINDINGS

Combining tracked flagella with mathematical modelling has the potential to reveal new mechanistic insight. By providing the capability as a free-to-use software package, we hope that this ability to accurately quantify the flagellar waveform in large populations of motile cells will enable an abundant array of diagnostic, toxicological and therapeutic possibilities, as well as creating new opportunities for assessing and treating male subfertility.

STUDY FUNDING/COMPETING INTEREST(S)

M.T.G., G.C., J.C.K-B. and D.J.S. gratefully acknowledge funding from the Engineering and Physical Sciences Research Council, Healthcare Technologies Challenge Award (Rapid Sperm Capture EP/N021096/1). J.C.K-B. is funded by a National Institute of Health Research (NIHR) and Health Education England, Senior Clinical Lectureship Grant: The role of the human sperm in healthy live birth (NIHRDH-HCS SCL-2014-05-001). This article presents independent research funded in part by the NIHR and Health Education England. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. The data for experimental set (2) were funded through a Wellcome Trust-University of Birmingham Value in People Fellowship Bridging Award (E.H.O.).The authors declare no competing interests.

Kinematic Sub-Populations in Bull Spermatozoa: A Comparison of Classical and Bayesian Approaches

The ejaculate is heterogenous and sperm sub-populations with different kinematic patterns can be identified in various species. Nevertheless, although these sub-populations are statistically well defined, the statistical differences are not always relevant. The aim of the present study was to characterize kinematic sub-populations in sperm from two bovine species, and diluted with different commercial extenders, and to determine the statistical relevance of sub-populations through Bayesian analysis. Semen from 10 bulls was evaluated after thawing. An ISAS®v1 computer-assisted sperm analysis (CASA)-Mot system was employed with an image acquisition rate of 50 Hz and ISAS®D4C20 counting chambers. Sub-populations of motile spermatozoa were characterized using multivariate procedures such as principal components (PCs) analysis and clustering methods (k-means model). Four different sperm sub-populations were identified from three PCs that involved progressiveness, velocity, and cell undulatory movement. The proportions of the different sperm sub-populations varied with the extender used and in the two species. Despite a statistical difference (p < 0.05) between extenders, the Bayesian analysis confirmed that only one of them (Triladyl®) presented relevant differences in kinematic patterns when compared with Tris-EY and OptiXcell®. Extenders differed in the proportion of sperm cells in each of the kinematic sub-populations. Similar patterns were identified in Bos taurus and Bos indicus. Bayesian results indicate that sub-populations SP1, SP2, and SP3 were different for PC criteria and these differences were relevant. For velocity, linearity, and progressiveness, the SP4 did not show a relevant difference regarding the other sperm sub-populations. The classical approach of clustering or sperm subpopulation thus may not have a direct biological meaning. Therefore, the biological relevance of sperm sub-populations needs to be reevaluated.

Seasonal variations in quantitative and qualitative sperm characteristics in fertile and subfertile stallions

Horses are seasonal breeders with a natural breeding season beginning in spring and extending through midsummer. In this study, quantitative and qualitative parameters of chilled stallion semen were compared between fertile and subfertile stallions and between the breeding and the non-breeding season. Semen quality parameters compared included ejaculate volume, sperm concentration, total sperm number, sperm morphology, and computer-assisted semen analysis (CASA)-derived sperm movement characteristics obtained from two groups of warmblood stallions (n=8; four fertile stallions and four subfertile stallions), which differ in the seasonal pregnancy rate 80 %–90 % (fertile) vs. 40 %–60 % (subfertile). A total of 64 ejaculates were collected from the stallions (n=8; four in the breeding season and four in the non-breeding season of each stallion). No significant differences in the semen quality parameters between the fertile and the subfertile stallions in the non-breeding season were observed. However, in the breeding season the proportion of morphologically normal sperm, total motility, progressive motility, average path velocity (VAP), and curvilinear velocity (VCL) were significantly higher in the fertile group (P<0.05) when compared with the subfertile group. In addition, a significant seasonal variation in the proportion of morphological normal sperm was found in the fertile group between the breeding and the non-breeding season (P<0.05). Moreover, significant seasonal variations (P<0.05) in CASA parameters of mean VAP, straight line velocity (VSL), and beat-cross frequency (BCF) were observed in the fertile and the subfertile stallions, which tended to be lower in the non-breeding season. In conclusion, differences between the fertile and the subfertile stallions were observed only in the breeding season, and a few of CASA-derived parameters seemed to be significantly lower during the non-breeding season in both the fertile and the subfertile stallions.

Machine learning to further improve the decision which boar ejaculates to process into artificial insemination doses

Current artificial insemination (AI) laboratory practices assess semen quality of each boar ejaculate to decide which ones to process into AI doses. This decision is aided with two, world-wide used, motility parameters that come available through computer assisted semen analysis (CASA). This decision process, however, still results in AI doses with variable and sometimes suboptimal fertility outcomes (e.g., small litter size). The hypothesis was that the decision which ejaculates to process into AI doses can be improved by adding more data from CASA systems, and data from other sources, in combination with a data-driven model. Available data consisted of ejaculates that passed the initial decision, and thus, were processed into AI doses and used to inseminate sows. Data were divided into a training set (6793 records) and a validation set (1191 records) for model development, and an independent test set (1434 records) for performance assessment. Gradient Boosting Machine (GBM) models were developed to predict four fertility phenotypes of interest (gestation length, total number born, number born alive, and number of stillborn piglets). Each fertility phenotype was considered as a numeric and as a binary outcome parameter, totaling to eight different fertility phenotypes. Data used to further improve the decision process originated from four sources: 1) CASA information, 2) boar ejaculate information, 3) breeding value estimations, and 4) weather information. These data were used to create seven prediction sets, where each new set added parameters to the ones included in the previous set. The GBM models predicted fertility phenotypes with low correlations (for numeric phenotypes) and area under the curve values (for binary phenotypes) on the test data. Hence, results demonstrated that a combination of more data and GBM did not enable further improvement of the AI dose quality checks, resulting in the rejection of our hypothesis. However, our study revealed parameters affecting boar ejaculate fertility which were not used in today's decision process. These parameters (listed in the top 10 in at least four GBM models) included one parameter associated with boar ejaculate information, two with breeding value estimations, five with CASA information, and one with weather information. These parameters, therefore, should be further investigated for their potential value when assessing the quality of boar ejaculates in daily routine AI doses processing.

Carnosine treatment during human semen processing by discontinuous density gradient

The aim of this article was to evaluate the effects of different concentrations of carnosine added during human semen processing. Semen samples from 34 patients were submitted to processing by discontinuous density gradient centrifugation without (control) or with different concentrations of carnosine supplementation as follows: (a) 20 mM of carnosine supplementation on the layers of Percoll; and (b) 50 mM carnosine supplementation. Sperm samples were then washed with human tubal fluid medium and evaluated according to sperm kinetics and functional assessment. For statistical analysis, data were evaluated by a general linear model or a Friedman test, whenever appropriate. The 50 mM carnosine supplementation led to improved sperm mitochondrial activity when compared to untreated samples. Motility variables, such as percentage of motile and progressively motile spermatozoa, average path velocity, straight line velocity, curvilinear velocity and linearity, showed an improvement after semen processing irrespective of carnosine supplementation. Both concentrations of carnosine increased the beat-cross frequency (BCF) when compared to samples before processing. We conclude that carnosine supplementation in semen samples benefits sperm mitochondrial activity and BCF.

A collective tracking method for preliminary sperm analysis

Background

Total motile sperm count (TMSC) and curvilinear velocity (VCL) are two important parameters in preliminary semen analysis for male infertility. Traditionally, both parameters are evaluated manually by embryologists or automatically using an expensive computer-assisted sperm analysis (CASA) instrument. The latter applies a point-tracking method using an image processing technique to detect, recognize and classify each of the target objects, individually, which is complicated. However, as semen is dense, manual counting is exhausting while CASA suffers from severe overlapping and heavy computation.

Methods

We proposed a simple frame-differencing method that tracks motile sperms collectively and treats their overlapping with a statistical occupation probability without heavy computation. The proposed method leads to an overall image of all of the differential footprint trajectories (DFTs) of all motile sperms and thus the overall area of the DFTs in a real-time manner. Accordingly, a theoretical DFT model was also developed to formulate the overall DFT area of a group of moving beads as a function of time as well as the total number and average speed of the beads. Then, using the least square fitting method, we obtained the optimal values of the TMSC and the average VCL that yielded the best fit for the theoretical DFT area to the measured DFT area.

Results

The proposed method was used to evaluate the TMSC and the VCL of 20 semen samples. The maximum TMSC evaluated using the method is more than 980 sperms per video frame. The Pearson correlation coefficient (PCC) between the two series of TMSC obtained using the method and the CASA instrument is 0.946. The PCC between the two series of VCL obtained using the method and CASA is 0.771. As a consequence, the proposed method is as accurate as the CASA method in TMSC and VCL evaluations.

Conclusion

In comparison with the individual point-tracking techniques, the collective DFT tracking method is relatively simple in computation without complicated image processing. Therefore, incorporating the proposed method into a cell phone equipped with a microscopic lens can facilitate the design of a simple sperm analyzer for clinical or household use without advance dilution.

CASA-Mot in mammals: an update

Sperm motility is one of the most widely used parameters of sperm quality. Computer-aided sperm motility analysis (CASA-Mot) systems were developed to reduce the subjectivity of sperm motility assessment, and have had broad scientific and practical acceptance. In this review, the sources of variation and current applications of this technology and its relationships with other sperm quality tests are described in detail. Despite remarkable advances in the technique, there is still great need for standardisation in many species, and the numerous factors that affect the results make it difficult to provide universally accepted criteria for classifying semen samples based on sperm motility characteristics. The main fields for CASA-Mot include the study of male fertility and pathologies, evaluation of the effects of physical and chemical agents, improvement of epidemiological survey studies, more precise calculation of seminal doses for farm animals, realisation of basic studies about sperm function, improvement of sperm technologies such as cryopreservation and quality control analysis. Numerous relationships have been established between CASA-Mot and other sperm quality tests, although most of these parameters are complementary. Future CASA-Mot systems will probably be able to integrate several sperm quality parameters with motility.

CASA-Mot technology: how results are affected by the frame rate and counting chamber

For over 30 years, CASA-Mot technology has been used for kinematic analysis of sperm motility in different mammalian species, but insufficient attention has been paid to the technical limitations of commercial computer-aided sperm analysis (CASA) systems. Counting chamber type and frame rate are two of the most important aspects to be taken into account. Counting chambers can be disposable or reusable, with different depths. In human semen analysis, reusable chambers with a depth of 10µm are the most frequently used, whereas for most farm animal species it is more common to use disposable chambers with a depth of 20µm . The frame rate was previously limited by the hardware, although changes in the number of images collected could lead to significant variations in some kinematic parameters, mainly in curvilinear velocity (VCL). A frame rate of 60 frames s-1 is widely considered to be the minimum necessary for satisfactory results. However, the frame rate is species specific and must be defined in each experimental condition. In conclusion, we show that the optimal combination of frame rate and counting chamber type and depth should be defined for each species and experimental condition in order to obtain reliable results.

CASA: tracking the past and plotting the future

The human semen sample carries a wealth of information of varying degrees of accessibility ranging from the traditional visual measures of count and motility to those that need a more computational approach, such as tracking the flagellar waveform. Although computer-aided sperm analysis (CASA) options are becoming more widespread, the gold standard for clinical semen analysis requires trained laboratory staff. In this review we characterise the key attitudes towards the use of CASA and set out areas in which CASA should, and should not, be used and improved. We provide an overview of the current CASA landscape, discussing clinical uses as well as potential areas for the clinical translation of existing research technologies. Finally, we discuss where we see potential for the future of CASA, and how the integration of mathematical modelling and new technologies, such as automated flagellar tracking, may open new doors in clinical semen analysis.

Seminal plasma proteins modify the distribution of sperm subpopulations in cryopreserved semen of rams with lesser fertility

Any physiological mechanism involved in sperm selection and semen improvement has effects on heterogeneous sperm populations. This is mainly due to the fact that sperm populations within a single ejaculate have considerable heterogeneity for many variables, such as motility which is meaningful in terms of understanding how some sperm cells possess fertility advantages as compared with other cells. In the present research, initially there was a multivariate and clustering analysis used to assess sperm motility data from cryopreserved ram semen to identify subpopulations and compare the distribution of these clusters between rams with lesser and greater fertility. There were four classifications made of sperm subpopulations (clusters): CL1 fast/linear/progressive sperm; CL2 fast/non-linear sperm; CL3 very fast/linear sperm with vigorous beating and CL4 slow/non-linear sperm. Rams with greater fertility had a lesser proportion of sperm considered as "hyperactivated" (CL2) and a greater proportion of slow and non-linear sperm (CL4) than sperm of rams with lesser fertility. In addition, the effects were assessed for the capacity of seminal plasma (SP) and interacting SP proteins (iSPP) that were present during different seasons of the year to improve the distribution of sperm within subpopulations of semen from rams with lesser fertility. The iSPP and SP were obtained by artificial vagina (AV) and electroejaculation (EE) during breeding and non-breeding seasons and added to thawed semen. All the aggregates had a significant effect on the distribution of sperm subpopulations and effects differed among seasons of the year and depending on collection method used. Even though, future studies are needed to assess the contribution of each subpopulation on ram sperm fertility, it is important that a multivariate analysis be used to evaluate the effect of a treatment on sperm quality variables.

Artificial neural networks for the definition of kinetic subpopulations in electroejaculated and epididymal spermatozoa in the domestic cat

This study was designed for the identification of different sperm kinetic subpopulations in feline semen using artificial neural networks (ANNs) and for the evaluation of the effect of ejaculation on motility patterns of these subpopulations. Seven tomcats presented for routine orchiectomy were electroejaculated, and after 5 days, orchiectomized and epididymal tail sperms were collected. Sperm motility characteristics were evaluated using a computer-assisted sperm analyzer that provided individual kinetic characteristics of each spermatozoon. A total of 23 400 spermatozoa for electroejaculated and 9200 for epididymal tail samples were evaluated using a multivariate approach, comprising principal component analysis and ANN classification. The multivariate approach allowed the identification and characterization of three different and well-defined sperm subpopulations. There were significant differences before (epididymal tail spermatozoa) and after (electroejaculated sperm) ejaculation in sperm kinetic subpopulation characteristics. In both epididymal and ejaculated samples, the majority of subpopulation was characterized by high velocity and progressiveness; however, the electroejaculated samples showed significantly higher values, suggesting that the microenvironment of the epididymal tail could affect the sperm motility or, alternatively, seminal plasma could increase the kinetic characteristics of the spermatozoa, indicating that only after ejaculation, the spermatozoa express their motility potential. Nevertheless, further studies are required to clarify the functional significance of each kinetic subpopulation.

Effect of semen preparation on casa motility results in cryopreserved bull spermatozoa

Computer-assisted sperm analyzers (CASA) have become the standard tool for evaluating sperm motility and kinetic patterns because they provide objective data for thousands of sperm tracks. However, these devices are not ready-to-use and standardization of analytical practices is a fundamental requirement. In this study, we evaluated the effects of some settings, such as frame rate and frames per field, chamber and time of analysis, and samples preparations, including thawing temperature, sperm sample concentration, and media used for dilution, on the kinetic results of bovine frozen-thawed semen using a CASA. In Experiment 1, the frame rate (30-60 frame/s) significantly affected motility parameters, whereas the number of frames per field (30 or 45) did not seem to affect sperm kinetics. In Experiment 2, the thawing protocol affects sperm motility and kinetic parameters. Sperm sample concentration significantly limited the opportunity to perform the analysis and the kinetic results. A concentration of 100 and 50 x 10(6) sperm/mL limited the device's ability to perform the analysis or gave wrong results, whereas 5, 10, 20, and 30 x 10(6) sperm/mL concentrations allowed the analysis to be performed, but with different results (Experiment 3). The medium used for the dilution of the sample, which is fundamental for a correct sperm head detection, affects sperm motility results (Experiment 4). In this study, Makler and Leja chambers were used to perform the semen analysis with CASA devices. The chamber used significantly affected motility results (Experiment 5). The time between chamber loading and analysis affected sperm velocities, regardless of chamber used. Based on results recorded in this study, we propose that the CASA evaluation of motility of bovine frozen-thawed semen using Hamilton-Thorne IVOS 12.3 should be performed using a frame rate of 60 frame/s and 30 frames per field. Semen should be diluted at least at 20 x 10(6) sperm/mL using PBS. Furthermore, it is necessary to consider the type of chamber used and perform the analysis within 1 or 2 min, regardless of the chamber used.

ABSENCE OF SPERM WITH RAPID MOTILITY IS NOT DETRIMENTAL TO IVF OUTCOME MEASURES WHEN ICSI IS USED

The objective of the current study was to investigate the association between rapid motility of sperm and IVF outcome when ICSI is used for insemination of oocytes. The first IVF cycle of women up to age 42 were evaluated. Patients were classified into groups by the presence/absence of sperm with rapid motility ("A" sperm) in the specimen before and after sperm preparation. Group 1 had 0% A sperm prewash and 0% A postwash (n = 45); Group 2 had 0% A sperm prewash but some A sperm postwash (n = 47); Group 3 had A sperm both pre and postwash (n = 141). Statistical analysis demonstrated no difference in the fertilization, PRs, or implantation rates in the three groups. These data suggest that absence of sperm with rapid motility postseparation of sperm from seminal plasma is not detrimental to IVF outcome when ICSI is used for insemination.

Semen banking—is it now feasible for captive endangered species?

This article proposes that serious consideration should now be given to the establishment of banks of genetic material from rare and endangered species. In the light of advances in the technology associated with semen assessment and preservation, the limitations that have so far discouraged the practice of semen freezing and banking can now be minimized and circumvented. The authors review these developments and suggest that semen preservation should be reconsidered as a practical means of preserving the genetic diversity currently contained within captive stocks of wild animals.

Computer-assisted motility analysis of spermatozoa obtained after spermatogonial stem cell transplantation in the mouse

OBJECTIVE

To study the motility characteristics of epididymal spermatozoa after spermatogonial stem cell transplantation.

DESIGN

Testicular cells from fertile donor mice were transplanted to the testis of genetically sterile recipient mice. Three to nine months later, the epididymal spermatozoa were isolated and used for a computer-assisted sperm motility analysis. Spermatozoa from fertile adult mice were used as control.

SETTING

Murine transplantation model in an academic research environment.

ANIMAL(S)

Donors, 6-day-old male C57Bl x WBRej F1 mice; acceptors, 4- to 6-week-old W/W(v) mice of the same genetic background.

INTERVENTION(S)

Two to 10 microL from a 30-million/mL testicular cell suspension was injected through the efferent duct in the rete testis.

MAIN OUTCOME MEASURE(S)

Vitality, concentration, motility, individual sperm movement, and hyperactivity of the spermatozoa.

RESULT(S)

Vitality was comparable between the two groups; the concentration, motility, and hyperactivity of posttransplantation spermatozoa were significantly reduced. The movement pattern of the individual spermatozoon was normal at the time of isolation but decreased more rapidly during in vitro culture, compared with the case in controls. This difference already had reached a significant level 3 hours after culture, which is comparable with the duration of an IVF procedure.

CONCLUSION(S)

The reduced fertilization rate after IVF can thus be explained by a lower number of motile spermatozoa and the faster decrease of the individual sperm movement parameters.

Applications and interpretation of computer-assisted sperm analyses and sperm sorting methods in assisted breeding and comparative research

Theoretical and practical knowledge of sperm function is an essential requirement in almost every aspect of modern reproductive technology, if the overarching objective is the eventual production of live offspring. Artificial insemination (AI) techniques depend on the availability of high quality semen, whether fresh, diluted and stored, or frozen. Assessing such semen for quality and the likelihood of fertility is therefore also important, as much time, resources and effort can easily be wasted by using poor samples. Some semen technologies are aimed not at quality assessment, but at attempting to skew the breeding outcomes. Sex preselection by separating the male- and female-bearing spermatozoa using flow cytometry is now practised routinely in the agricultural industry, but speculatively it may eventually be possible to use other genetic markers besides the sex chromosomes. A moment's reflection shows that although sex-biasing flow cytometry technology is well developed and generally fulfils its purpose if presorting of sperm quality is adequate, other technologies aimed specifically at semen assessment are also sophisticated but provide inadequate data that say little about fertility. This is especially true of instrumentation for objective sperm motility assessment. Here we aim to examine this technological paradox and suggest that although the sperm assessment equipment might be sophisticated, the shortcomings probably lie largely with inappropriate objectives and data interpretation. We also aim to review the potential value and use of sperm sexing technology for non-domestic species, arguing in this case that the limitations also lie less with the technology itself than with the applications envisaged. Finally, the potential application of a sorting method directed at motility rather than sperm DNA content is discussed.

Identification of sperm subpopulations with specific motility characteristics in stallion ejaculates

The aim of this study was to test the presence of separate sperm subpopulations, with specific motility characteristics, in stallion ejaculates by using a computer-assisted semen motility analysis (CASA) system. Motility data were analyzed with a hierarchical clustering of variables based on a correlation or covariance matrix to select like parameters of sperm motility descriptors that better explain the kinetics of spermatozoa. The statistical analyses clustered the whole motile sperm population in both fresh and 24 h stored ejaculates into four separate groups. There were significant differences in the distribution of the four subpopulations (P < 0.001) as well as in the total sperm number and the percentage of total motility (P < 0.01) in fresh semen among the five stallions tested. Our results show that separate subpopulations of spermatozoa with different motility characteristics coexist in stallion ejaculates. These subpopulations were maintained, although with a less-progressive motion pattern, after 24 h of storage. The study of subpopulations in ejaculates that have confirmed fertilizing capacity showed that the majority of the motile spermatozoa in these ejaculates are included in a subpopulation with high progressive motility and low linearity, and the ejaculates with proven fertility that have a total sperm count > or = 20 x 10(9) spermatozoa/ejaculate show all of their motile sperm included in this subpopulation. Our results show that the use of the CASA system is a relatively simple approach to the study of sperm subpopulation patterns in equine ejaculates.

Use of the Sperm Quality Analyzer (SQA II-C) for the assessment of dog sperm quality

In the present study, an automated system for sperm analysis, the Sperm Quality Analyzer (SQA II-C), was tested as a potential tool for the assessment of dog sperm quality. In the first experiment the device displayed a good repeatability of measurements for semen of medium and high quality, as evidenced by a low coefficient of variance (CV; 0.08), whereas a high CV (0.46) was obtained for one dog with semen of inferior quality. In the second experiment, seven different sperm concentrations (25-300 x 106/ml), obtained by dilutions in Hepes-TALP medium were stored for 48 h at room temperature. A concentration dependent increase in sperm motility index (SMI) was shown, reaching a plateau at 150 x 106 spermatozoa/ml. For all sperm concentrations, the SMI value decreased significantly after 24 h, indicating the importance of sperm motility for SMI values. For sperm concentrations lower than 150x106/ml, highly significant correlations [r=0.80;p<0.05] were established between SMI values on one hand and sperm concentration, and semen parameters expressing the overall semen sample quality on the other hand (experiment 3) while non-significant or low correlations were found between SMI values and other individual sperm parameters. In experiment 4, significantly high correlations (r=0.97) were found between mean SMI values and post-thaw motility and progressive motility assessed subjectively. In conclusion, our study indicates that both motility and concentration largely influence SMI values and that the SQA II-C saturates at 150 x 106 fresh spermatozoa/ml. In our opinion, the SQA II-C may be a useful and objective device to assess the post-thaw motility of dog sperm.

Molecular evaluation of two major human sperm fibrous sheath proteins, pro-hAKAP82 and hAKAP82, in stump tail sperm

OBJECTIVE

To determine whether mutations in the pro-hAKAP82 gene and the resulting pro-hAKAP82 and hAKAP82 proteins were associated with the infertility seen in a patient with stump tail sperm.

DESIGN

Case report.

SETTING

Academic research and teaching environment, tertiary care hospital.

PATIENT(S)

A single, infertile Caucasian male diagnosed with essentially 100% stump tail sperm.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Electrophoresis, silver staining, and immunoblotting of patient and control sperm proteins; RII (type II regulatory subunit of protein kinase-A) overlay assay of patient and control sperm proteins, partial DNA sequence analysis of patient's pro-hAKAP82 gene; indirect immunofluorescence and immunogold electron microscopy of patient and control sperm.

RESULTS(S)

No significant abnormalities in the size or amount of pro-hAKAP82 and hAKAP82 or in the ability of these proteins to bind the regulatory subunit of protein kinase-A were identified in the patient's sperm. Partial sequence analysis of the patient's pro-hAKAP82 gene was identical to the published normal sequence. Indirect immunofluorescence and immunoelectron microscopy of sperm localized pro-hAKAP82/hAKAP82 to the sperm flagellum and demonstrated that the proteins were present in a disorganized, amorphous region, which apparently represented the fibrous sheath.

CONCLUSION(S)

These results suggest that, although pro-hAKAP82 and hAKAP82 localize to the correct structural component of the flagellum and are not directly responsible for the stump tail phenotype, they are unable to assemble normally into the fibrous sheath. Although this study did not identify abnormalities in the pro-hAKAP82 gene or its resulting proteins in a patient with stump tail sperm, several regions of the gene and protein remain to be examined.

Effects of holding time during cooling and of type of package on plasma membrane integrity, motility and in vitro oocyte penetration ability of frozen-thawed boar spermatozoa

The effect of a prolonged holding time (HT) during cooling on plasma membrane integrity (PMI), motility and in vitro oocyte penetration ability of boar spermatozoa frozen-thawed in different types of package was investigated. Boar semen was frozen in a split-sample design using 3 different HTs (3, 10 and 20 h) during cooling and three different types of freezing package: Maxi-straws, Medium-straws and FlatPacks. Assessment of PMI (SYBR-14 and propidium iodide, fluorescence microscopy) and sperm motility (visually and with CASA) was done during cooling (at 32 degrees C, 15 degrees C, 5 degrees C) and post-thaw (PT). The in vitro oocyte penetration ability of the spermatozoa was tested only PT, using a homologous in vitro penetration assay (hIVP). During cooling the HTs used had no significant (p<0.05) effect on either PMI or percentage of motile spermatozoa Post-thaw PMI was significantly higher (p<0.05) for 10 h and 20 h HT compared with 3 h, and the percentage of motile spermatozoa decreased significantly with 20 h HT as opposed to 3 h and 10 h. Regarding the freezing packages, the FlatPacks and Maxi-straws yielded significantly more PMI than did the Medium-straws (p<0.05). Post-thaw motility was significantly higher for FlatPacks than for straws, in terms of both percentage motile spermatozoa, and sperm velocity and lateral head displacement (LHD). The hIVP did not show any significant differences among the HTs, although FlatPacks yielded a significantly higher penetration rate and more spermatozoa per penetrated oocyte (p<0.05) than did the straws. Changes in motility patterns, toward a more circular motility during cooling and PT, could be noticed where individual spermatozoa showed a capacitation-like motility pattern. The changes were more obvious with 10-h and 20-h HTs than with 3-h HT.

Value of the hamster oocyte test and computerised measurements of sperm motility in predicting if four or more viable embryos will be obtained in an IVF cycle

The experimental group consisted of men from 81 couples waiting for in vitro fertilization (IVF), about half of whom had sperm dysfunction defined by a negative post-coital test. A diagnostic semen sample was subjected to a hamster oocyte penetration test (HOPT) after stimulation of the acrosome reaction with A23187 +/- pentoxifylline and to computerized sperm motility measurements (CASA) as well as conventional semen analysis according to the WHO protocol. Logistic regression was used to identify parameters that predicted the probability of achieving four or more viable embryos at IVF among the 65 couples from whom four or more oocytes were collected. The number of oocytes available and whether the woman had previously been pregnant (ever pregnant) were important factors but once these had been taken into account a number of sperm parameters had additional predictive power. The most useful of these were the percentage sperm static (CASA) or the percent sperm progressively motile (conventional semen analysis) in the Percoll preparation. A model incorporating the number of oocytes collected, ever pregnant and percentage sperm static achieved 85% correct prediction of outcome in the experimental dataset but only 62% correct prediction in an independent set of 280 IVF cycles. The percentage of hamster oocytes penetrated was a significant predictor but had no advantage over simple motility measurements. The results illustrate the difficulty of basing a prognosis for achieving satisfactory fertilization in IVF on the properties of spermatozoa.

Effect of freezing and thawing rates on the post-thaw viability of boar spermatozoa frozen in FlatPacks and Maxi-straws

The effects of different freezing and thawing rates on the post-thaw motility and membrane integrity of boar spermatozoa, processed as split samples in Maxi-straws or flat PET-plastic packages (FlatPack) were studied. A programmable freezing device was used to obtain freezing rates of either 20, 50 or 80 degrees C/min. Thawing of the samples was performed in a bath of circulating water; for 40s at 50 degrees C or 27s at 70 degrees C for Maxi-straws and 23s at 35 degrees C, 13s at 50 degrees C or 8s at 70 degrees C for the FlatPacks. Sperm motility was assessed both visually and with a computer assisted semen analysis (CASA) apparatus, while plasma membrane integrity was assessed using the fluorescent probes Calcein AM and ethidium homodimer-1. Temperature changes during freezing and thawing were monitored in both forms of packaging. Values for motile spermatozoa, sperm velocity and lateral head displacement variables were significantly (p<0.05) higher for samples frozen in FlatPacks than in Maxi-straws, with superior results at higher thawing rates. Freezing at 50 degrees C/min yielded better motility than 20 or 80 degrees C/min, although the effect was rather small. Neither freezing rate nor thawing rate had any effect on membrane integrity (p>0.05). A significant boar effect was seen for several parameters. The most striking difference in temperature courses between containers was a 4-5-fold lowering of the thawing rate, between -20 and 0 degrees C, in the center of the Maxi-straw, compared with the FlatPack. This is apparently due to the insulating effect of the thawed water in the periphery of the Maxi-straw. The improvement in sperm motility seen when using the FlatPack appears to be related to the rapid thawing throughout the sample, which decreases the risk of cell damage due to recrystallization during thawing. Since sperm motility patterns have been reported to be correlated with fertility both in vitro and in vivo it is speculated that the use of the FlatPack might improve the results when using frozen-thawed boar spermatozoa for artificial insemination.

Basic aspects of frozen storage of semen

Basic concepts of cryopreservation and the causes of cryoinjury are reviewed. The possible roles of cryoprotectants and additives are considered in the context of their putative interactions with the sperm plasma membrane. Modern approaches to the laboratory assessment of spermatozoa after freeze-thawing are also briefly discussed.

Semen analysis at the turn of the century: an evaluation of potential uses of new sperm function assays

Semen analysis is a critical assay in the evaluation of infertility and may yield critical information regarding the etiology and prognosis of many types of reduced male fertility. However, basic semen analysis does not directly measure sperm fertilizing capacity, or many of the biochemical events both prior to and subsequent to fertilization. In the last two decades numerous assays of sperm function have been developed. These assays can be classified as: 1) Assays of general biochemistry and ultrastructure, 2) Assays of zona binding and oocyte penetration, and 3) Assays of postpenetration events. Sperm function assays not only allow an accurate diagnosis of many infertilities not diagnosed by the semen analysis, but can also lead to improved treatment modalities. In this review, basic semen analysis and many sperm function assays are briefly reviewed. Novel uses of sperm function are demonstrated in brief case studies.

Autostage sperm tracing system for semen evaluation

To overcome the limitation of the microscope field, the study proposed an autostage sperm tracing system (ASTS), which could trace a particular sperm for a long time and distance. The ASTS was constructed by assembling a commercial microscope, an image frame grabber, a personal computer, and a motorized stage. Its performance was tested by evaluating 6 semen samples and by comparing the evaluation with those of other semen evaluations. The ASTS broke through the limitation of the microscope field and traced a particular sperm as long as possible. It analyzed the sperm track and calculated the motility parameters, such as curvilinear velocity (Vcl), straight-line velocity (Vsl), and linearity (L(in)). The sperm quality was then evaluated in real time, and the user could decide to capture or abandon a particular sperm in the IVF The ASTS enables users to evaluate sperm progression for a long time and to have the global quality of a particular sperm in real time. Its open structure has the flexibility for micromanipulating a semen sample, and has the potential application associated with a modern IVF technique.

Relationship between sperm motility and the processing and tyrosine phosphorylation of two human sperm fibrous sheath proteins, pro-hAKAP82 and hAKAP82

Sperm motility is regulated by the cAMP-dependent protein kinase (protein kinase-A)-mediated phosphorylation of a group of largely unidentified flagellar proteins. Human AKAP82 (hAKAP82) and its precursor protein, pro-hAKAP82, are members of the A-kinase anchor protein (AKAP) family. These proteins tether protein kinase-A to the fibrous sheath of human spermatozoa and presumably localize the activity of the kinase near specific targets in the sperm flagellum. In this way, pro-hAKAP82 and hAKAP82 may be involved in regulating sperm motility. Similar to its homologues in other species, pro-hAKAP82 is proteolytically processed to hAKAP82. However, the amount of processing of pro-hAKAP82 in human spermatozoa is less than the amount of processing of the precursor in other species. We postulated that this lower extent of processing may be related to lower percentages of human sperm motility. In addition, both pro-hAKAP82 and hAKAP82 are tyrosine phosphorylated in a capacitation-dependent manner. Since capacitation is associated with hyperactivated motility, we postulated that tyrosine phosphorylation of pro-hAKAP82/hAKAP82 is associated with changes in motility. However, using a combination of immunofluorescence and immunoblotting approaches, we found no evidence for an association between either processing or tyrosine phosphorylation of pro-hAKAP82/hAKAP82 and significant differences in motility in spermatozoa from normal men.

Application of the upgraded image superimposition system (SIAS) to the assessment of sperm kinematics

Dedicated software for semiautomatic objective motility assessment, based on image superimposition (SIAS), was upgraded in order to allow automatic reading of sperm tracks whilst keeping the advantages of visual check instead of the digital images of classic computer-aided sperm analysis (CASA) systems. The new system is very fast and accurate and allows an excellent reading of sperm motility in standard semen analysis. Moreover, using this system, an attempt was made to define numerically straight-line velocity (VSL), curvilinear velocity (VCL) and linearity (LIN) in each WHO sperm motility class. At 21 frames sec-1, ROC curves analysis determined the following: Class 1 (typical of WHO grade 'a'): VSL > or = 23 microns sec-1 and LIN > or = 0.58; class 2 (typical of WHO grade 'b'): VSL > 10 and < 23 microns sec-1 and LIN > or = 0.58; class 3: VSL > 10 microns sec-1 and LIN < 0.58 (this additional class was added to differentiate nonstraight progressive motility from classes 1 and 2); class 4 (typical of WHO grade 'c'): VSL < or = 10 microns sec-1. The numerical definition of sperm motility classes may contribute towards standardization in the objective evaluation of sperm kinematics.

Are sperm motion parameters influenced by varicocele ligation?

OBJECTIVE

To document objectively, improvements in sperm motion parameters in subfertile men after varicocele ligation with the use of computer-aided sperm analysis.

DESIGN

Retrospective chart review.

SETTING

An academic clinical environment.

PATIENT(S)

Thirty-four men with varicocele as the primary cause of infertility who underwent a physical examination, hormonal profile, and Doppler ultrasound evaluation.

INTERVENTION(S)

Computer-aided sperm analysis was performed before and after either subinguinal or laparoscopic varicocele ligation.

MAIN OUTCOME MEASURE(S)

Patients were followed up for 3-18 months after operation, and average computer-aided sperm analysis values were obtained before and after operation. Computer-aided sperm analysis values were analyzed by paired Student's t-test, with special reference to motility and sperm motion parameters.

RESULT(S)

After varicocele ligation, patients demonstrated increases in mean sperm density and in the overall distribution of sperm with rapid velocity, although the increases were not statistically significant. Mean measures of straightness, linearity, and track speed also were increased after operation, but only progressive sperm velocity was increased to a statistically significant level.

CONCLUSION(S)

Because progressive velocity has been a primary computer-aided sperm analysis parameter predictive of male fertility and the success of assisted reproductive techniques, we conclude that varicocele ligation results in improvements in semen parameters, especially the key parameter of progressive sperm velocity.

A method for quantifying differential expansion within hydrating hydrophilic matrixes by tracking embedded fluorescent microspheres

A method is described for quantifying the pattern of deformation within a matrix and is demonstrated by analyzing the expansion of polymer hydrophilic matrix tablets. The fundamental features of the method are the incorporation of nondiffusing markers into the matrix and the subsequent tracking of these markers during deformation. Since the markers are too large to diffuse, their individual movement reflects the translocation of the surrounding matrix, and the separation between pairs of markers reveals any perturbation in the intervening area. By tracking many markers, the pattern of deformation within a matrix can be ascertained. The method was demonstrated on hydrating hydrophilic matrix tablets, using fluorescent microspheres as nondiffusing markers which were observed with a confocal laser scanning microscope. Analysis of the tracks showed a wave of expansion moving from the exterior toward the core, with the greatest and earliest expansion found in the outer regions. The results also showed that even as deeper layers started to expand the outer layers continued to swell.

Sperm subpopulations in boar (Sus scrofa) and gazelle (Gazella dama mhorr) semen as revealed by pattern analysis of computer-assisted motility assessments

The aim of this study was to test the suitability of "pattern analysis" for the exploration of data provided by computer-assisted semen analysis methods. Data sets derived from the examination of boar sperm responses to bicarbonate and caffeine (measurements on 3208 spermatozoa) and from studies of semen cryopreservation in Mohor gazelles (7278 spermatozoa) were reanalyzed. A nonhierarchical classification method was used to generate initial subgroups of spermatozoa (9 for boar, 13 for gazelle). The subgroup centroids were fused, yielding three boar sperm subpopulations and four gazelle sperm subpopulations distinguished by sperm behaviors. Bicarbonate and caffeine both induced major transitions (p < 0.0001) of boar sperm behavior, detected as shifts in group membership (from group 2, i.e., active but nonlinear movement, into group 1, i.e., linear, rapid movement). Some spermatozoa (approximately 3%) were refractory to both caffeine and bicarbonate. The gazelle sperm subpopulation structure was affected by the inclusion of equex (sodium triethanolamine lauryl sulfate) in the cryoprotective diluents. Equex suppressed the appearance of spermatozoa with erratic behavior (p < 0.0001; high curvilinear velocity, low linearity, low straight-line velocity) after cryopreservation. The proportion of these erratic spermatozoa was positively correlated with animal age (r = 0.68, p = 0.029). Pattern analysis revealed novel aspects of the data not seen in the original investigations and usefully supplemented the more standard data analysis approaches.

A follow-up study of semen quality and fertility in men with varicocele testis and in control subjects

OBJECTIVE

To evaluate semen quality and fecundity in a group of men with initially untreated varicocele testis, in comparison with control subjects.

PATIENTS, SUBJECTS AND METHODS

In a prospective, longitudinal study, 77 men (39 with varicocele and 38 control subjects) were evaluated in 1989 and re-investigated after 8 years. Fifty-seven men (29 with varicocele, 28 controls) were available for evaluation and they all completed a questionnaire. Semen from a total of 46 men (24 with varicocele) was compared with findings in 22 men from the control group.

RESULTS

There was a decline in sperm count in the control group from 80 x 10(6)/mL to 55 x 10(6)/mL over the 8-year period, but nearly no change in the sperm count in the men with varicocele. The withdrawal rate from each group was the same and included both men with and without reduced semen quality. There were no differences between the groups in sperm motility values (straight-line velocity, curvilinear velocity) evaluated using computer-assisted semen analysis. Paternity was achieved by 10 of 14 men in the varicocele group, compared with 14 of 16 in the control group.

CONCLUSIONS

There was no evidence that varicocelectomy might benefit patients, because the sperm concentration did not decline among men with varicocele over time. Computer-assisted semen analysis provided a good assessment of various sperm motility characteristics and we recommend evaluation using such objective methods, to allow comparison among studies

New system for long-term monitoring of sperm motility: EDTA effect on semen

Many drugs act as sperm stimulants and are of clinical value for male infertility. Current research deals with the physiological mechanisms of sperm motility/sperm stimulation and how long the effect lasts. For such a study, long-term monitoring of sperm motility becomes essential for traditional semen evaluation. A new system was designed to deal with the microscopic images of semen. Its performance was evaluated by studying the effect of EDTA on sperm motility. EDTA increased sperm curvilinear velocity (Vcl) and straight-line velocity (Vsl) by 31 and 20%. EDTA also prolonged the duration of motility by 68 and 61%, respectively. However, EDTA had less effect on the linearity of forward progression (Lin). The proposed system can analyze semen and does well at monitoring sperm motility for short term and long term. It may be valuable to test the possible role of sperm stimulation for male infertility and assisted reproduction.