The influence of a mineral oil overlay on the zona pellucida binding potential of human spermatozoa

Summary.  The objective of the study was to evaluate the effect of mineral oil on zona pellucida binding potential of human spermatozoa. The study compared zona binding using micro volume droplets under mineral oil as apposed to micro droplets in cryopreservation straws. Spermatozoa from eight proven fertile sperm donors were used. One hundred and fifty five matched hemizonae in 50 μl, 100 μl and 200 μl insemination sperm droplets were co-incubated; (i) under mineral oil and (ii) 0.5 ml plastic cryopreservation straws. The results were analysed to determine the number of the zona bound spermatozoa during each experiment. Microvolumes with an oil overlay had a decrease in sperm bound per hemizona of 38% (mean±SD; 563±415 vs. 921±597), 51% (mean±SD; 392±359 vs. 800±566 sperm) and 18% (mean±SD; 502±369 vs. 618±445) in 200 μl, 100 μl and 50 μl respectively, compared to microvolumes in cryopreservation straws. It was concluded that mineral oil may have some detrimental factors which interfere with zona binding of spermatozoa.     

L- carnitine in idiopathic asthenozoospermia: a multicenter study

Summary. The aim of the study described here was to evaluate any possible effect of L-carnitine on spermatozoal motility in a group of patients with unexplained asthenozoospermia in four different infertility centres. One hundred patients received 3 g d⁻¹ of oral L-carnitine for 4 months. Sperm parameters were studied before, during and after this treatment. Motility was also studied by means of a computer-assisted sperm analysis.
The results of the study indicate that L-carnitine is able to increase spermatozoal motility, both in a quantitative and in a qualitative manner (per cent motile spermatozoa increased from 26.9±1.1% to 37.7 ± 1.1% [ P < 0.001]; per cent spermatozoa with rapid linear progression increased from 10.8 ± 0.6% to 18.0 ± 0.9% [ P < 0.001]; mean velocity increased from 28.4 ± 0.6 μm s⁻¹ to 32.5 ± 0.8 μm s⁻¹ [ P < 0.001]; linearity index increased from 3.7 ± 0.1 to 4.1±0.1 [ P < 0.001], especially in the subgroup of patients with poor rapid linear progression of spermatozoa (per cent of motile spermatozoa increased from 19.3± 1.9% to 40.9± 1.4% [ P < 0.001], and per cent of spermatozoa with rapid linear progression increased from 3.1±0.4% to 20.3±1.6% [ P < 0.001]) An increase in spermatozoal output was also observed (total number of ejaculated spermatozoa increased from 142.4 ± 10.3 10⁶ to 163.3 ± 11.0 × 10⁶ [ P < 0.001]). The authors conclude that oral administration of L-carnitine may improve sperm quality at least in patients with idiopathic asthenozoospermia.     

Correlation between neutral alpha-glucosidase activity and sperm DNA fragmentation

To evaluate the association between neutral α-glucosidase (NAG) activity and sperm DNA fragmentation (DFI), ejaculates from 24 men undergoing evaluation for sperm DNA damage as a part of infertility assessment were analysed. The mean ± SD and range for the semen quality of the 24 ejaculates are as follows: volume (3.1 ± 1.3, 1.8–6.0 ml); sperm concentration (45.6 ± 41.1, 1.3–151.2 × 10⁶ ml⁻¹); sperm motility (52.8 ± 28.8, 1–95%); sperm with fragmented DNA (17.6 ± 15.4, 1.7–56.0%); sperm with immature chromatin (9.6 ± 3.8, 2.5–19.1%); NAG activity (37.9 ± 18.3, 4.4–75.3 mU ml⁻¹). The only sperm parameter significantly correlated with neutral α-glucosidase is the percentage of sperm DFI [correlation coefficient ( r ) = 0.4376, P  = 0.03].     

Sperm—oocyte interaction: studies on the kinetics of zona pellucida binding and acrosome reaction of human spermatozoa

Summary. Successful sperm-oocyte interaction depends, among other things, on sperm capacitation, which is defined by acrosomal and motility alterations. In the study described here the authors evaluated different aspects of this gamete interaction in humans. Specifically, the authors studied (1) the relationship between the number of spermatozoa bound to the zona pellucida and sperm concentration and incubation period, (2) the capacitation status and kinetics of acrosome reaction among the zona-bound spermatozoa, and (3) the effect of human follicular fluid on the zona-binding potential and acrosome status of spermatozoa from different men. The results indicated a concentration of 10⁷ cells ml⁻¹ after 15 min of coincubation to be the optimum for zona binding. The number of sperm bound after 0, 3 and 5 h of incubation was the same. In addition, spermatozoa incubated for 3 or 5 h underwent the acrosome reaction (range 9–43%) on the zona surface within 15 min of binding. The maximum percentage of acrosome-reacted spermatozoa was reached after 60 min of binding. Follicular fluid affected the sperm populations selectively, since it did not influence zona binding capacity in all cases. The data enhances the authors' understanding of critical events occurring before fertilization.     

Gonadal and Extragonadal Sperm Reserves of the Brazilian Nelore Zebu (Bos indicus)

Summary: Gonadal and extragonadal sperm reserves were estimated through hemocytometric method in six Nelore zebu bulls, aging 4–6 years, with normal spermatogenesis, and kept at sexual rest. Gonadal sperm reserve was estimated to be 47.8 ± 5.8 times 10⁶ sperm cells/g testis parenchyma and 9.8 ± 1.7 times 10⁹ sperm cells/testis. Using a time divisor of 4.94 days the daily sperm production was estimated to be 10.0 ± 0.9 times 10⁶ sperm cells/g testis parenchyma/day and 2.0 ± 0.3 times 10⁹ sperm cells/testis/day. Epididymal sperm reserve amounted 11.9 ± 1.6 times 10⁹ spermatozoa/organ, distributed as follows: 35.3 ± 3.6% in the head, 16.9 ± 1.7% in the body and 47.7 ± 3.7% in the tail.
Zusammenfassung: Gonadale und extragonadale Spermareserven des brasilianischen Nelore-Zebu (Bos indicus)
Bei sechs Nelore-Zebubullen im Alter von vier bis sechs Jahren mit normaler Spermatogenese und unter sexueller Karenz wurden mit einer haemocytometrischen Methode die gonadalen und extragonadalen Spermareserven bestimmt. Für die gonadale Spermareserve wurden Werte von 47.8 ± 5.8 times 10⁶ Spermatozoen/g Hodenparenchym und 9.8 ± 1.7 times 10⁹ Spermatozoen/Hoden gefunden. Unter Benutzung eines Zeitdivisors von 4.94 Tagen berechnet sich die tägliche Spermaproduktion zu 10.0 ± 0.9 times 10⁶ Spermatozoen/g Hodenparenchym/Tag und 2.0 ± 0.3 times 10⁹ Spermatozoen/Hoden/Tag. Die Spermareserve im Nebenhoden betrug 11.9 ± 1.6 times 10⁹ Spermatozoen/Nebenhoden in folgender Verteilung: 35.3 ± 3.6% im Nebenhodenkopf, 16.9 ± 1.7% im Nebenhodenkörper und 47.7 ± 3.7% im Nebenhodenschwanz.     

Pentoxifylline increases sperm penetration into zona-free hamster oocytes without increasing the acrosome reaction

Summary. Several drugs have been used to stimulate human sperm motility, including 3-deoxy-adenosine, caffeine, and pentoxifylline. Pentoxifylline is an inhibitor of the phosphodiesterase and may stimulate sperm motility by increasing the intracellular levels of cAMP. In this study we have evaluated the effect of pentoxifylline in the outcome of the sperm penetration assay into zona-free hamster oocytes. Twenty-seven semen samples, obtained for diagnostic purposes, were used. After the motile sperm were selected by the swim-up technique, the samples were divided into two aliquots. One aliquot was incubated with 1 mg ml⁻¹ of pentoxifylline at 37 °C, 5% CO₂ for 30 min. The control aliquot was incubated with culture medium. The samples were then washed and resuspended in fresh, pentoxifylline-free medium, at a sperm concentration of 10 × 10⁶ cells ml⁻¹. One hundred microlitres of each sperm suspension was then deposited under oil and 30–40 zona-free hamster oocytes were added. After 6 h of gamete coincubation, the percentage of penetrated oocytes and the number of decondensed sperm heads were evaluated. The percentage of acrosome-reacted sperm was evaluated using the Pisum sativum lectin. The percentage of zona-free hamster oocytes penetrated was increased after pentoxifylline-treatment. The percentage of acrosome reacted sperm and the number of decondensed sperm heads per egg were not different between the control and the pentoxifylline-treated groups. The results suggest that the beneficial effect of pentoxifylline upon the sperm cells is not mediated by stimulation of the acrosome reaction.     

Influence of different uropathogenic microorganisms on human sperm motility parameters in an in vitro experiment

Summary. The influence of different uropathogenic microorganisms ( E. coli, enterococcus, Pseudomonas aeruginosa, Staphylococcus saprophyticus, Candida albicans ) on human sperm motility was studied in vitro with a computer-assisted sperm analyser (CASA).
Native ejaculates were prepared with the swim-up technique and adjusted to 22 times 10⁶ spermatozoa ml⁻¹. The sperm suspension was artificially infected with microorganisms in concentrations varying from 2 times 10³ to 2 times 10⁷. Sperm motility was examined directly after incubation, 2, 4 and 6 h later using the Mika motion analysis®, a computer-based, automatic motility analysis.
Former results with E. coli (serotype 06) could be confirmed that a significant inhibitory effect on sperm motility was associated with bacterial growth. Experiments with the enterococcus strain and Staphylococcus saprophyticus indicated no significant influence on sperm motility parameters. Tests with Pseudomonas aeruginosa showed a decrease of progressive motility according to time, but not to different bacterial concentrations. A significant inhibitory effect of Candida albicans was only detected in the samples with the initial bacterial concentration of 2 times 10⁷ microorganisms ml⁻¹.     

Sirolimus May Reduce Fertility in Male Renal Transplant Recipients

Assessment of sex hormones in organ transplant recipients suggests that sirolimus may impair testicular function. The aim of this study was to evaluate the frequency and severity of sirolimus-associated alterations in sperm parameters and their impact on fathered pregnancy rate. An observational study was carried out in male patients aged 20–40 years who received a kidney transplant during 1995–2005. Patients were sent a questionnaire by post, and sperm analysis was proposed. The fathered pregnancy rates according to the immunosuppressive regimen were estimated and compared using the Poisson model. Complete information was obtained from 95 out of 116 recipients. Patients treated with sirolimus throughout the post-transplant period had a significantly reduced total sperm count compared to patients who did not receive sirolimus (28.6 ± 31.2 × 10⁶ and 292.2 ± 271.2 × 10⁶, respectively; p = 0.006), and a decreased proportion of motile spermatozoa (22.2 ± 12.3% and 41.0 ± 14.5%, p = 0.01). Moreover, the fathered pregnancy rate (pregnancies/1000 patient years) was 5.9 (95% CI, 0.8–42.1) and 92.9 (95% CI, 66.4–130.0) in patients receiving sirolimus-based and sirolimus-free regimens, respectively (p = 0.007). Of six patients in whom sirolimus treatment was interrupted, only three showed a significant improvement in sperm parameters. Sirolimus is associated with impaired spermatogenesis and, as a corollary, may reduce male fertility.     

Scavenging effect of N-acetyl-L-cysteine against reactive oxygen species in human semen: a possible therapeutic modality for male factor infertility?

Summary. A new approach to reduce the level of reactive oxygen species (ROS) in human semen by using N-acetyl-L-cysteine (NAG) was evaluated. Semen samples were incubated with or without NAC (1.0 nig ml⁻¹) at room temperature. The chemiluminescent signal of the oxidation of luminol was detected by means of an MTP reader after 0, 20, 40, 60 and 120 min, respectively, using 200 μM luminol. In addition, the dose-dependent action of NAC (0.1, 1.0 and 5.0 mg ml⁻¹) and the influence of NAC on functional sperm parameters (motility and acrosome reaction) were studied.
ROS levels decreased significantly after 20 min incubation with NAG. This reduction was greater in the high ROS group (>30 000 counts/10⁷ viable sperm at t = 0) than in the low ROS group (<30 000). In addition, a marked dose-dependence of NAC was observed. Concerning sperm function, total sperm motility improved after incubation with NAC, but no significant change was observed with respect to the acrosome reaction.
NAC (at concentrations of 1.0 mg ml⁻¹) significantly reduced ROS in human semen and showed the possibility of improving impaired sperm function. After further testing NAC might be useful for the treatment of male infertility patients.     

The relationship between ejaculated ram sperm mitochondrial protein synthesis and motility

Summary. D-chloramphenicol, at concentrations of 20 and 40 μg/ml, inhibited over 80% of the newly synthesized mitochondrial proteins expressed by incorporation of ³H-amino acid mixture. At concentrations of 20 and 40 μgml⁻¹, D-chloramphenicol enhanced the collective motility of washed ram spermatozoa. The collective motility measured by the multichannel Reflectospermiograph system, significantly enhanced the motility wave frequencies and amplitudes by 24–17% and 65–32%, respectively. Furthermore, the longevity of the collective motility was prolonged by 12–19%. In about 20% of the cases, when the original sperm motility was low, it was found that 40 μg ml⁻¹ D-chloramphenicol has maximum stimulation effect on sperm motility in inverse fashion. Since the mitochondria are located adjacent to the motility initiation area, it can be speculated that the mitochondrial protein(s) directly inhibiting the axonemal-ATPase activity or indirectly blocking sperm metabolite, are essential for maintaining sperm motility.     

Seminal fibronectin-like antigen and transferrin concentrations in infertile and fertile men

Summary.  Fibronectin like antigen (Fn) and transferrin (Trs) levels were measured in the seminal plasma of 40 fertile and 102 infertile men. The concentrations of both proteins were significantly ( P <0.001) higher in the fertile controls compared to the infertile groups. The levels of Fn and Trs (mean value ± SEM) in the fertile men were 857.9 ± 9.8 μg ml^-1 and 164.0 ± 6.5 μg ml^-1, respectively; in the azoospermic men ( n = 17) 552.7 ± 24.65 μg ml^-1 and 20.7 ± 2.19 μg ml^-1, respectively; in the group of severe oligozoospermia ( n = 35) 568.34 ± 25.7 μg ml^-1 and 31.1 ± 4.18 μg ml^-1, respectively; in the moderate oligozoospermic group ( n = 8) 572.50 ± 47.9 μg ml^-1 and 43.4 ± 15.4 μg ml^-1 respectively, and in the asthenozoospermic group ( n = 26) 512.76 ± 40.4 μg ml^-1 and 47.0 ± 7.9 μg ml^-1, respectively. Of special interest was the finding from a group of 16 normospermic men (partners of couples with unexplained infertility) who showed significantly lower levels of Fn like antigen, 632.5 ± 26.9 μg ml^-1 ( P <0.001) and Trs 41.8 ± 6.94 μg ml^-1 ( P <0.0001) compared to normals. No correlation was found between Fn levels with either Trs or FSH levels or sperm count. In conclusion, our results indicate that male infertility is associated with changes in seminal plasma Fn like antigen concentrations and that it can be possibly used as an index of sperm fertilizing capacity.     

Experimental hypercholesterolaemia in rabbits. Effect on lipid domains in homologous spermatozoa

Summary. The distribution of membrane filipin sterol complexes (FSC) in the plasma membrane of the acrosomal region (PMAR) of rabbit sperm from epididymis and testis, in normal and hypercholesterolaemic rabbits, was examined at ultrastructural level. Membrane FSC were quantitatively analysed on freeze fracture replicas of filipin-treated cells. Cauda epididymal sperm shows a significant increase in filipin sterol complexes concentration in PMAR of hypercholesterolaemic animals compared to normal rabbits. Hypercholesterolaemic animals had 0.53±0.08 FSC μm⁻² in the marginal segment of PMAR and 0.26±0.03 FSC μm⁻² for normal animals. In the principal piece we found 0.70±0.07 FSC μm⁻² for hypercholesterolaemic and 0.43±0.03 FSC μm⁻² for control animals. We also counted 0.58±0.04 FSC μm⁻² in the equatorial segment of PMAR for hypercholesterolaemic and 0.38±0.03 FSC μm⁻² for normal animals respectively. The FSC concentration of testicular sperm, like sperm from corpus and caput of epididymis in hypercholesterolaemic animals, did not differ from the controls. Cholesterol, phospholipids and cholesterol: phospholipid ratio in caudal epididymal sperm from treated males did not differ from controls. Only the sphingomyelin concentration decreases in cauda epididymal sperm from hypercholesterolaemic males compared to controls.
The results presented in this paper suggest that the lipidic domains in PMAR of hypercholesterolaemic rabbits changes when the gametes go through the epididymis.—     

Laser-assisted cryopreservation of single human spermatozoa in cell-free zona pellucida

Improved procedure for efficient cryopreservation of single human spermatozoa in cell-free human zona pellucida is reported. We used a diode laser system for efficient and precise creation of a single hole into the zona pellucida of a degenerated or immature human oocyte. This allowed the extraction of the cytoplasm using a micropipette with a diameter of 10–15  μm. Through the same opening, human spermatozoa were inserted into the empty zona. We used motile and laser immobilized spermatozoa. Immobilized sperm were obtained by a single laser irradiation delivered in the vicinity of the sperm tail prior to insertion. This new immobilization procedure was shown to have no deleterious effect on membrane integrity and sperm viability. Following sperm transfer into the zona, the laser-drilled hole was closed with an oil droplet which was expelled from the micropipette during withdrawal to avoid loss of spermatozoa. This facilitated detection of the otherwise translucent zona during the cryopreservation procedure. After thawing, all cryopreserved zonae (20/20) could be successfully retrieved. Spermatozoa were recovered from the zona pellucida through the hole used for insertion. The rate of sperm recovery for initially motile spermatozoa was 80% vs. 92% for laser immobilized spermatozoa. Sperm viability was 81% and 84%, respectively, detected by a Hoechst stain. This technique makes cryopreservation of single human spermatozoa easy and feasible and appears beneficial for couples with severe male infertility and for those facing repeated surgical sperm extraction.     

Current status of reproductive function in Japanese fertile men: international collaborative project on a study of partners of pregnant women

The data on reproductive function in 255 Japanese fertile men resident in the Kawasaki/Yokohama area in Japan were described. The sperm concentration was 107.9 ± 97.4 × 10⁶/mL. The semen volume was 3.2 ± 1.5 mL and percentage motile spermatozoa (grade A + B in WHO criteria) was 56.8% ± 14.7%. The evidence for secular changes in semen quality and other changes in male reproductive health is inconclusive, although regional differences would appear to be stronger. The present study is the first large-scaled prospective survey on the reproductive function of Japanese normal men proven fertility, which was planned as an international comparative study.     

Twenty-Year Experience With Heart Transplantation for Infants and Children With Restrictive Cardiomyopathy: 1986–2006

Idiopathic restrictive cardiomyopathy (RCM) is a rare cardiomyopathy in children notable for severe diastolic dysfunction and progressive elevation of pulmonary vascular resistance (PVR). Traditionally, those with pulmonary vascular resistance indices (PVRI) >6 W.U. × m² have been precluded from heart transplantation (HTX). The clinical course of all patients transplanted for RCM between 1986 and 2006 were reviewed. Preoperative, intraoperative and postoperative variables were evaluated. A total of 23 patients underwent HTX for RCM, with a mean age of 8.8 ± 5.6 years and a mean time from listing to HTX of 43 ± 60 days. Preoperative and postoperative (114 ± 40 days) PVRI were 5.9 ± 4.4 and 2.9 ± 1.5 W.U. × m², respectively. At time of most recent follow-up (mean = 5.7 ± 4.6 years), the mean PVRI was 2.0 ± 1.0 W.U. × m². Increasing preoperative mean pulmonary artery pressure (PA) pressure (p = 0.04) and PVRI > 6 W.U. × m² (χ²= 7.4, p < 0.01) were associated with the requirement of ECMO postoperatively. Neither PVRI nor mean PA pressure was associated with posttransplant mortality; 30-day and 1-year actuarial survivals were 96% and 86%, respectively. Five of the seven patients with preoperative PVRI > 6 W.U. × m² survived the first postoperative year. We report excellent survival for patients undergoing HTX for RCM despite the high proportion of high-risk patients.     

The hemizona assay (HZA) as an experimental model to evaluate the inhibition of sperm binding to the murine zona pellucida by isolated zona pellucida protein

Compelling evidence has demonstrated that zona binding represents gamete recognition by sperm binding with high affinity and specificity to complex glycoproteins of the zona pellucida. In the present study we evaluated the hemizona assay (HZA) in the investigation of the interaction of mouse spermatozoa with unfertilized murine oocytes and hemizonae after exposure to solubilized murine zonae pellucidae proteins. The zonae pellucidae were isolated from ovarian tissue following described mincing techniques. The sperm binding characteristics of murine spermatozoa were studied by using SDS-PAGE isolated ZP2 (+/- 120 Kd) and ZP3 (+/- 83 Kd) components of the zona pellucida. Sperm receptor activity was examined in a competitive gamete binding fashion using the HZA as an indicator of sperm/zona interaction. The results illustrated that isolated, solubilized ZP2 and ZP3 glycoprotein moieties of the zona pellucida inhibited sperm binding to hemizonae and oocytes when compared to controls, and that the HZA can be utilized as an internally controlled homologous bioassay to evaluate the effects of zona pellucida proteins on tight binding of spermatozoa to the zona pellucida.     

Use of a novel non-steroidal anti-inflammatory drug, nimesulide, in the treatment of abacterial prostatovesiculitis

Summary. Nimesulide, a novel non-steroidal anti-inflammatory drug, was used in cases of abacterial prostato-vesiculitis. Thirty patients with a mean age of 33.7 years (range 18–58) were studied. Nimesulide was administered orally 100 mg b.i.d. for three cycles of 10 d each. Dysuric symptoms, semen analysis, and transrectal ultrasound were examined during the study. The concentration-time curves of nimesulide (NIM) and its metabolite, hydroxynimesulide (OH-NIM) in seminal fluid were also evaluated after single oral administration (100 mg) using an HPLC technique. Following administration of the drug, the Cmax was reached in seminal fluid at the second hour for NIM (with a mean value ± SD of 0.58 ± 0.13 μg ml⁻¹) and at the fourth hour for OH-NIM (2.98 ± 0.38 μg ml⁻¹). Maximal seminal fluid concentrations compared to blood plasma levels were observed at the fourth hour for both substances (31.73 ± 2.34% for NIM; 31.87 ± 8.66% for OH-NIM.
Dysurie symptoms were relieved in 20 (66%) patients. A clear amelioration of inflammatory signs were observed at transrectal ultrasound evaluation in 16 (54%) patients. No statistically significant changes of sperm count and motility in the whole sample were observed, while a significant reduction in the number of abnormal forms occurred. From these results, nimesulide appears to be an effective anti-inflammatory drug with a good diffusion into the genital apparatus and low side-effects.     

Diurnal variations in scrotal temperature of normal men and patients with varicocele before and after treatment

Scrotal temperature was monitored using a portable data recorder for periods of 24 h in six normal volunteers and 48 infertile patients with unilateral varicocele while subjects pursued their regular daily activities. Temperatures during sleep ( T _s) were generally higher than daytime values ( T _D), probably as a consequence of thermal insulation in bed. These diurnal variations were found to be less pronounced in the infertile patients than in volunteers (T_s- T_D= 0.29°C ± 0.06°C us 0.88°C ± 0.12°C;P<0.01). Moreover, scrotal temperatures at night of patients and volunteers were indistinguishable statistically, but were different during daytime hours. After successful ligation or embolization of the spermatic vein in 16 patients, no change in scrotal temperature was observed. Although sperm counts were higher after treatment, this difference was not significant (67.4 ± 17.2 × 10⁶ vs 105.8 ± 25.5 ± 10⁶; P>0.05). The data support the view that varicocele-related damage to the testis results from a lack of adequate cooling, and that treatment does not normalize the temperature pattern.     

The influence of sperm density on the motility characteristics of washed human spermatozoa

To study the effects of sperm density on the results of computer-assisted semen analysis (CASA), 10 washed semen samples were diluted and measured with the CellTrak/S CASA system in a concentration range of 10–180×10⁶ spermatozoa/ ml. All sperm motility parameters were influenced to some extent by sperm density. The motility percentage was influenced significantly in 5 samples ( P< 0.005), the straight line velocity in all samples (P<0.0005 in 7 samples), the curvilinear velocity in 3 samples ( P< 0.005), the linearity in 9 samples (P<0.0005 in 6 samples) and the lateral head displacement in 9 samples (P< 0.005 in 6 samples). In general, the CellTrak/S data are influenced significantly if sperm density exceeds 50 × 10⁶ spermatozoa/ml.
The influence of sperm density on the motility parameters can be explained both by the accuracy of the CASA system and by actual changes in the motility of the spermatozoa. In the light of other published studies, it is concluded that sperm motility measurements with CASA systems should be assessed using 25–50 × 10⁶ spermatozoa/ml, especially in studies concerning lateral head displacement and the linearity, as in sperm hyperactivation studies.