Poor Sperm Chromatin Condensation Is Associated with Cryopreservation-Induced DNA Fragmentation and Cell Death in Human Spermatozoa.

Background/Objectives: Semen cryopreservation is routinely performed in fertility clinics for a variety of reasons, including fertility preservation and storage of donor sperm, yet the freeze-thaw process leads to cellular damage via ice crystal formation, osmotic shock, and supraphysiological levels of oxidative stress. Sperm resistance to damage during the freeze-thaw process varies widely, yet the intrinsic factors associated with sperm cryotolerance are largely unknown. The study aimed to investigate whether poor chromatin condensation renders sperm vulnerable to DNA fragmentation and cell death induced by the freeze-thaw process. Methods: Participants (n = 51) from the general community who met the inclusion criteria collected a semen sample after 3-8 days of abstinence. Neat semen samples underwent traditional semen analysis, aniline blue (AB)-eosin staining for chromatin condensation, the terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay for DNA fragmentation, and the Annexin V assay for apoptosis/necrosis, prior to being cryopreserved using the liquid nitrogen vapour method and stored at -196 °C. Stored samples were later thawed at room temperature and processed using density gradient centrifugation. Motile sperm concentration, DNA fragmentation and apoptosis/necrosis were analysed in post-thaw samples. Results: As indicated by a significant interaction effect in linear mixed models, an increased proportion of AB-positive sperm in the pre-freeze sample exacerbated the adverse effect of freezing on sperm DNA fragmentation (p = 0.004), late apoptosis (p = 0.007), and necrosis (p = 0.007). AB-staining was positively correlated with all three parameters in the post-thaw sample (all rs ≥ 0.424, all p < 0.01) and remained significant after adjusting for neat sperm concentration (all partial rs ≥ 0.493, all p < 0.01). Similarly, AB-staining was significantly correlated with the percentage point change in sperm DNA fragmentation (rs = 0.366, p = 0.014) and necrosis (rs = 0.403, p = 0.009), both of which remained significant after adjusting for neat sperm concentration (both partial rs ≥ 0.404, both p < 0.01), and borderline significantly correlated with percentage point change in late apoptosis (rs = 0.307, p = 0.051). Conclusions: Sperm with poorly condensed chromatin may be more susceptible to cellular damage during the freeze-thaw process, independent of pre-freeze sperm concentration. These findings may help to explain the intrinsic variation in sperm resistance to cryodamage within and between individuals that is poorly understood.

Ovulation induction and subfertile untreated conception groups offer improved options for interpreting risks associated with ART.

PURPOSE: To identify and characterise appropriate comparison groups for population studies of health outcomes in ART-conceived births: ovulation induction (OI), subfertile untreated and fertile natural conceptions. Our secondary objective was to examine whether known risks of pregnancy complications and adverse birth outcomes in ART births are elevated in comparison with subfertile (untreated and OI) conception groups. METHODS: We linked State and Commonwealth datasets to identify all live and stillbirths (≥ 20 weeks) in Western Australia from 2003 to 2014 by method of conception. Demographic characteristics, maternal pre-existing conditions, adverse obstetric history and pregnancy complications were compared across conception groups. Generalised estimating equations were used to estimate adjusted risk ratios (aRRs) and 95% confidence intervals (CI) for pregnancy complications and birth outcomes in singletons. RESULTS: We identified 9456 ART, 3870 OI, 11,484 subfertile untreated and 303,921 fertile naturally conceived deliveries. OI and subfertile untreated groups more closely resembled the ART group than the fertile group; however, some differences remained across parity, maternal age, pre-existing conditions and obstetric history. In multivariate analyses, ART singletons had greater risks of placental problems (e.g. placenta praevia aRR 2.42 (95% CI 1.82-3.20)) and adverse birth outcomes (e.g. preterm birth aRR 1.38 (95% CI 1.25-1.52)) than the subfertile untreated group, while OI singletons were more similar to the subfertile group with higher risk of preeclampsia and gestational diabetes. CONCLUSION: OI and subfertile untreated conception groups offer improved options for interpreting health outcomes in ART births. Pregnancy complications (particularly placental disorders) and adverse outcomes at delivery are more common following ART.

Post-incident psychosocial interventions after a traumatic incident in the workplace: a systematic review of current research evidence and clinical guidance.

Background: After a traumatic incident in the workplace organisations want to provide support for their employees to prevent PTSD. However, what is safe and effective to offer has not yet been established, despite many organisations offering some form of intervention after a traumatic event.Objective: To systematically review the evidence for post-incident psychosocial interventions offered within one month of a workplace trauma, and to compare the content, effectiveness and acceptability of these interventions. Given the lack of a yet clearly established evidence-base in this field, we sought to examine both published empirical research as well as guidelines published by expert groups working with staff in high-risk roles.Methods: We conducted systematic searches for empirical research across bibliographic databases and searched online for clinical practice guidelines to April 2023. We were also referred to potentially relevant literature by experts in workplace trauma. Both empirical research and clinical guidelines were appraised for their quality.Results: A total of 80 research studies and 11 clinical practice guidelines were included in the review. Interventions included Critical Incident Stress Debriefing (CISD), Critical Incident Stress Management (CISM), unspecified Debriefing, Trauma Risk Management (TRiM), Psychological First Aid (PFA), EMDR, CBT and group counselling. Most research and guidance were of poor quality. The findings of this review do not demonstrate any harm caused by CISD, CISM, PFA, TRiM, EMDR, group counselling or CBT interventions when delivered in a workplace setting. However, they do not conclusively demonstrate benefits of these interventions nor do they establish superiority of any specific intervention. Generic debriefing was associated with some negative outcomes. Current clinical guidelines were inconsistent with the current research evidence base. Nevertheless, interventions were generally valued by workers.Conclusions: Better quality research and guidance is urgently needed, including more detailed exploration of the specific aspects of delivery of post-incident interventions.

Organisations often seek to provide some form of psychosocial intervention after a traumatic event in the workplace.Previous reviews have contraindicated particular forms of 'debriefing', however, the evidence for post-incident psychosocial interventions in the workplace has not previously been systematically reviewed.Research evidence was generally of poor quality with limited evidence of effectiveness and clinical guidelines were inconsistent with the evidence. Nevertheless, research did not demonstrate harm from most established interventions and support was valued by workers.

Asthma and allergies in a cohort of adolescents conceived with ART.

RESEARCH QUESTION: Are asthma and allergies more common in adolescents conceived with assisted reproductive technologies (ART) compared with adolescents conceived without? DESIGN: The Growing Up Healthy Study (GUHS) is a prospective cohort study including ART-conceived offspring born between 1991 and 2001 in Perth, Australia. Their long-term health outcomes, including asthma and allergy parameters, were compared with those of their counterparts conceived without ART from the Raine Study Generation 2 (Gen2), born in 1989-1991. At age 14, 152 GUHS and 1845 Gen2 participants completed the following assessments: the International Studies of Asthma and Allergies in Childhood (ISAAC) questionnaire, spirometry, methacholine challenge testing and skin prick testing (SPT). RESULTS: No differences were detected in the prevalence of current asthma (7.7% versus 10.8%, adjusted odds ratio [aOR] 0.82 (95% CI 0.44-1.52), P = 0.530). Spirometry-measured lung volumes were larger in the ART adolescents. Bronchial hyperresponsiveness was less prevalent in the ART cohort (8.8 versus 18.6%, P = 0.006). Current allergic rhinoconjunctivitis (ARC) rates were significantly higher in the ART cohort (32.4% versus 25.2%, aOR 1.52 [95% CI 1.03-2.26], P = 0.036), with no cohort differences in atopic dermatitis. Food allergies were more prevalent in the ART cohort (20.7 versus 10.9%, aOR 1.89 [95% CI 1.17-3.06], P = 0.010) with more adolescents having a positive SPT (68.0% versus 45.4%, aOR 3.03 [95% 1.99-4.63], P < 0.001). CONCLUSIONS: This study reports no differences in asthma prevalence, slightly altered lung function, an increase in ARC, food allergies and positive SPT in the ART-conceived adolescents. These findings are important to families and healthcare providers and may open up possibilities for targeted screening and treatment. Further studies are required to confirm these findings.

Cohort profile: The Growing Up Healthy Study (GUHS)-A prospective and observational cohort study investigating the long-term health outcomes of offspring conceived after assisted reproductive technologies.

Worldwide, over 8 million children and adults are conceived following assisted reproductive technologies (ART), and their long-term health is of consequential public health interest. The objective of this paper is to describe the Growing up Healthy Study (GUHS) cohort in detail, publicise it and invite collaboration. Combining the data collected in the GUHS with other cohorts or databases will improve the much-needed knowledge about the effects of ART, and allow for better understanding of the long-term health outcomes of offspring conceived after ART. The GUHS cohort is a prospective observational study of adolescents and young adults conceived after assisted reproductive technologies (ART). It was established to determine if the long-term health of offspring conceived by ART differs from that of the general population. This was investigated by comparing a substantial number of health parameters to those of a representative population of offspring conceived without ART. The n = 303 GUHS participants were born between 1991-2001 in the two fertility clinics operating at the time in Perth, Western Australia, and undertook assessments at ages 14, 17 and 20, replicating the pre-defined study protocols from the reference cohort-the Raine Study. Participants were comprehensively phenotyped through detailed questionnaires, anthropometry, biochemical analyses, as well as age-specific assessments (asthma, atopy, cardiometabolic health, body composition, mental health, thyroid function, epigenetics and vision). To date the GUHS cohort has been used to study the methylation, cardiometabolic, and thyroid profiles, as well as respiratory and mental health. To summarise, the GUHS cohort provides a valuable addition to the limited knowledge of the long-term health outcomes of ART-conceived offspring.

Male age negatively influences clinical pregnancy rate in women younger than 40 years undergoing donor insemination cycles.

The influence of paternal age on clinical pregnancy was examined within younger patients undergoing donor insemination (DI) cycles in Western Australia. A retrospective analysis of 2142 DI cycles was carried out, including only women <40 years with no history of fertility problems. Logistic regression analysis was used to relate donor age to clinical pregnancy rate. Proportional hazards regression analysis was used to relate male age to time to pregnancy. Mediation analysis was conducted to adjust for influence of sperm concentration and motility. Analysis was controlled for female age, luteal-phase progesterone support and insemination year. There was no effect of female age on pregnancy rate or time to pregnancy. Older males (age ≥ 45 years) were significantly associated with a reduced pregnancy rate and longer time to pregnancy. Mediation analysis indicated that sperm concentration and motility did not fully account for the effect of male age on pregnancy. This study reveals an adverse effect of male age on clinical pregnancy in women <40 years of age that is not solely mediated by decreased sperm concentration or motility. This has implications for recruitment systems that attract older donors such as open-identity systems, which may benefit from actively recruiting younger donors.

Assisted reproductive technology and major birth defects in Western Australia.

OBJECTIVE: To estimate the prevalence of major birth defects diagnosed by 6 years of age in all births and terminations of pregnancy for fetal anomaly conceived by assisted reproductive technology (when this included intracytoplasmic sperm injection and in vitro fertilization [IVF]) and the remainder of nonassisted reproductive technology-conceived children born in Western Australia from 1994 to 2002. METHODS: This retrospective cohort study used data linkage between three population-based registers (Reproductive Technology Register, Western Australian Register of Developmental Anomalies, and Midwives' Notification of Birth System) to identify all assisted reproductive technology (n=2,911) and nonassisted reproductive technology (n=210,997) births with and without birth defects diagnosed by age 6 and all terminations of pregnancy for fetal anomaly. RESULTS: A major birth defect was diagnosed in 8.7% of assisted reproductive technology and 5.4% of nonassisted reproductive technology singletons (odds ratio [OR] 1.53, 95% confidence interval [CI] 1.30-1.79), as well as 7.1% of assisted reproductive technology twins and 5.9% of nonassisted reproductive technology twins of unlike sex (OR 1.08, 95% CI 0.77-1.51). The prevalence of birth defects in assisted reproductive technology singletons and twins decreased markedly over the study period. This change was evident across all three clinics contributing data over the whole study and was particularly marked for children conceived as a result of IVF. CONCLUSION: There has been a decrease in the prevalence of birth defects over time in children born as a result of assisted reproductive technology in Western Australia; however, the prevalence of major birth defects in assisted reproductive technology singletons remains increased compared with nonassisted reproductive technology singletons. LEVEL OF EVIDENCE: II.

Immunolocalisation of 11ß-HSD-1 and -2, glucocorticoid receptor, mineralocorticoid receptor and Na+ K+-ATPase during the postnatal development of the rat epididymis.

Glucocorticoids have been implicated in male reproductive function and 11ß-HSD-1 and -2, the glucocorticoid receptor (GR) and mineralocorticoid receptor (MR), all of which are known to modulate glucocorticoid action, have been localised in the adult rat epididymis, but their developmental expression has not been investigated. Na(+)K(+)-ATPase activity, responsible for sodium transport, is induced by both mineralocorticoids and glucocorticoids in the kidney and colon, and has been localised in epididymal epithelium. This study examined the immunolocalisation of 11ß-HSD-1 and -2, GR, MR and Na(+)K(+)-ATPase in rat epididymal epithelium (n = 5) at postnatal days (pnd) 1, 7, 15, 28, 40, 60, 75 and 104, and relative mRNA expression of 11ß-HSD-1 and -2, and GR at pre-puberty (pnd 28) and post-puberty (pnd 75). 11ß-HSD-1, GR and MR were localised in the epididymal epithelium from pnd 1, and 11ß-HSD-2 and Na(+)K(+)-ATPase reactivity from pnd 15. At pnd 28 there was maximal immunoreactivity for both the GR and MR and 11ß-HSD-1 and -2. 11ß-HSD-1 mRNA expression in the caput increased from pre- to post-puberty, whereas 11ß-HSD-2 mRNA expression fell over the same period (P < 0.01). GR mRNA expression was similar at pre- and post-puberty in both caput and cauda. Developmental changes in expression of 11ß-HSD-1 and -2 suggest that overall exposure of the epididymis to glucocorticoids increases post-puberty, but cell-specific expression of the 11ß-HSD enzymes still provides a capacity for intricate local control of glucocorticoid exposure.

Antigenic diversity is generated by distinct evolutionary mechanisms in African trypanosome species.

Antigenic variation enables pathogens to avoid the host immune response by continual switching of surface proteins. The protozoan blood parasite Trypanosoma brucei causes human African trypanosomiasis ("sleeping sickness") across sub-Saharan Africa and is a model system for antigenic variation, surviving by periodically replacing a monolayer of variant surface glycoproteins (VSG) that covers its cell surface. We compared the genome of Trypanosoma brucei with two closely related parasites Trypanosoma congolense and Trypanosoma vivax, to reveal how the variant antigen repertoire has evolved and how it might affect contemporary antigenic diversity. We reconstruct VSG diversification showing that Trypanosoma congolense uses variant antigens derived from multiple ancestral VSG lineages, whereas in Trypanosoma brucei VSG have recent origins, and ancestral gene lineages have been repeatedly co-opted to novel functions. These historical differences are reflected in fundamental differences between species in the scale and mechanism of recombination. Using phylogenetic incompatibility as a metric for genetic exchange, we show that the frequency of recombination is comparable between Trypanosoma congolense and Trypanosoma brucei but is much lower in Trypanosoma vivax. Furthermore, in showing that the C-terminal domain of Trypanosoma brucei VSG plays a crucial role in facilitating exchange, we reveal substantial species differences in the mechanism of VSG diversification. Our results demonstrate how past VSG evolution indirectly determines the ability of contemporary parasites to generate novel variant antigens through recombination and suggest that the current model for antigenic variation in Trypanosoma brucei is only one means by which these parasites maintain chronic infections.

Families, time, and well-being in Canada.

We study changes in time and money available to families with children from 1971 to 2006. Increases in incomes at the top of the Canadian income distribution since the mid-1990s have taken place without any significant increases in total family hours of paid work. On the other hand, for families in the middle of the income distribution, family income has stagnated, despite the fact that parents jointly supply significantly higher hours of paid work. If both time and money are valuable resources for the production of well-being for family members, these findings suggest that inequality in well-being has increased even more than inequality of income.

Mating by proxy: a novel perspective to donor conception.

How single, partnered lesbian, and partnered heterosexual women undertaking donor insemination rate the importance of donor characteristics is explored in the context of Trivers's parental investment theory. Consistent with this theory, single women placed higher value on biographical traits reflective of the donor's level of potential resources (occupation, hobbies, age) and good character compared with either partnered lesbian or heterosexual women.

Erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA) blocks differentiation and maintains the expression of pluripotency markers in human embryonic stem cells.

hESCs (human embryonic stem cells) have enormous potential for use in pharmaceutical development and therapeutics; however, to realize this potential, there is a requirement for simple and reproducible cell culture methods that provide adequate numbers of cells of suitable quality. We have discovered a novel way of blocking the spontaneous differentiation of hESCs in the absence of exogenous cytokines by supplementing feeder-free conditions with EHNA [erythro-9-(2-hydroxy-3-nonyl)adenine], an established inhibitor of ADA (adenosine deaminase) and cyclic nucleotide PDE2 (phosphodiesterase 2). hESCs maintained in feeder-free conditions with EHNA for more than ten passages showed no reduction in hESC-associated markers including NANOG, POU5F1 (POU domain class 5 transcription factor 1, also known as Oct-4) and SSEA4 (stage-specific embryonic antigen 4) compared with cells maintained in feeder-free conditions containing bFGF (basic fibroblast growth factor). Spontaneous differentiation was reversibly suppressed by the addition of EHNA, but, upon removing EHNA, hESC populations underwent efficient spontaneous, multi-lineage and directed differentiation. EHNA also acts as a strong blocker of directed neuronal differentiation. Chemically distinct inhibitors of ADA and PDE2 lacked the capacity of EHNA to suppress hESC differentiation, suggesting that the effect is not driven by inhibition of either ADA or PDE2. Preliminary structure-activity relationship analysis found the differentiation-blocking properties of EHNA to reside in a pharmacophore comprising a close adenine mimetic with an extended hydrophobic substituent in the 8- or 9-position. We conclude that EHNA and simple 9-alkyladenines can block directed neuronal and spontaneous differentiation in the absence of exogenous cytokine addition, and may provide a useful replacement for bFGF in large-scale or cGMP-compliant processes.

Identification and characterization of small-molecule ligands that maintain pluripotency of human embryonic stem cells.

hESCs (human embryonic stem cells) offer great potential for pharmaceutical research and development and, potentially, for therapeutic use. However, improvements in cell culture are urgently required to allow the scalable production of large numbers of cells that maintain pluripotency. Supplementing feeder-free conditions with either EHNA [erythro-9-(2-hydroxy-3-nonyl)adenine] or readily synthesized analogues of this compound maintains hESC pluripotency in the absence of exogenous cytokines. When the hESC lines SA121 or SA461 were maintained in feeder-free conditions with EHNA they displayed no reduction in stem-cell-associated markers such as Nanog, Oct4 (octamer-binding protein 4) and SSEA4 (stage-specific embryonic antigen 4) when compared with cells maintained in full feeder-free conditions that included exogenously added bFGF (basic fibroblast growth factor). Spontaneous differentiation was reversibly suppressed by the addition of EHNA, but EHNA did not limit efficient spontaneous or directed differentiation following its removal. We conclude that EHNA or related compounds offers a viable alternative to exogenous cytokine addition in maintaining hESC cultures in a pluripotent state and might be a particularly useful replacement for bFGF for large-scale or GMP (good manufacturing practice)-compliant processes.

Effect of antioxidant supplementation of cryopreservation medium on post-thaw integrity of human spermatozoa.

This study examined whether the addition of an antioxidant to cryopreservation medium could improve the post-thaw integrity of cryopreserved human spermatozoa, particularly from men with abnormal semen parameters. Semen samples were collected by masturbation and assessed following WHO standards. Normal (n = 23) and abnormal (n = 20) samples were divided into three aliquots prior to cryopreservation. The first aliquot remained untreated and was mixed with cryopreservation medium (in-house 1:1). The second and third aliquots were mixed with cryopreservation medium containing either 100 micromol or 200 micromol vitamin E analogue. Samples were frozen at -10 degrees C per minute to -80 degrees C, then plunged into liquid nitrogen. Thawed samples were assessed for motility, vitality and DNA integrity. Split-plot repeated-measures ANOVA was used to assess within-subject (dose) and between-group (normal/abnormal) differences in post-thaw motility index, vitality staining and DNA fragmentation. Vitamin E dose was significantly associated with post-thaw motility (P = 0.041) and the pattern of response across doses was similar for normal and abnormal groups. Post-thaw motility was significantly improved by the addition of 200 micromol vitamin E (P = 0.006), but neither vitality nor sperm DNA fragmentation were altered. These results suggest that the addition of vitamin E to cryopreservation medium improves post-thaw motility.

Ku heterodimer-independent end joining in Trypanosoma brucei cell extracts relies upon sequence microhomology.

DNA double-strand breaks (DSBs) are repaired primarily by two distinct pathways: homologous recombination and nonhomologous end joining (NHEJ). NHEJ has been found in all eukaryotes examined to date and has been described recently for some bacterial species, illustrating its ancestry. Trypanosoma brucei is a divergent eukaryotic protist that evades host immunity by antigenic variation, a process in which homologous recombination plays a crucial function. While homologous recombination has been examined in some detail in T. brucei, little work has been done to examine what other DSB repair pathways the parasite utilizes. Here we show that T. brucei cell extracts support the end joining of linear DNA molecules. These reactions are independent of the Ku heterodimer, indicating that they are distinct from NHEJ, and are guided by sequence microhomology. We also demonstrate bioinformatically that T. brucei, in common with other kinetoplastids, does not encode recognizable homologues of DNA ligase IV or XRCC4, suggesting that NHEJ is either absent or mechanistically diverged in these pathogens.

Potential sperm donors', recipients' and their partners' opinions towards the release of identifying information in Western Australia.

BACKGROUND: The aim of this study was to examine Western Australian potential sperm donors' and recipients' opinions towards the release of identifying information and their intentions to disclose. METHODS: Forty-five potential sperm donors, 33 recipients and 12 partners completed an anonymous questionnaire regarding their opinions on the release of identifying information, whether a child should be told about the manner of their conception, the level of expected contact of donor with future donor offspring and the importance of anonymity in their decision to donate. RESULTS: Slightly less than one-half (48.9%) of potential donors indicated that they would still donate if their identity was revealed to future offspring. When asked whether they would consider contact with offspring, 80% responded positively, with 42% favouring one-off contact. The majority of recipients (82%) and partners (92%) were planning to inform their offspring about the manner of their conception, with 69% of recipients believing that the offspring should receive identifying information about the donor. Recipients were ambivalent about the level of contact between their offspring and the donor. CONCLUSION: These results suggest that the move to an open-identity donor system in Western Australia will benefit the majority of recipient parents who are intending to disclose; however, it also suggests a 50% decline in the number of potential sperm donors.

Long-run consequences of parental paid work hours for child overweight status in Canada.

This paper explores the connection between the labour market and child overweight status in Canada. The labour market is a social institution which plays a critical role in determining how families live their day-to-day lives, for example, how much time and which parts of the day are available for cooking, eating and exercise. Using longitudinal data from the Statistics Canada National Longitudinal Survey of Children and Youth, we find that a history of higher hours of paid work by mothers (but not fathers) is associated with a higher probability of being 'at risk of overweight'/overweight for children aged 6-11. The policy implication we draw from this work is that additional support to better enable parents to engage in paid work without penalty to their own health or that of their children is clearly warranted.

The genome sequence of Trypanosoma cruzi, etiologic agent of Chagas disease.

Whole-genome sequencing of the protozoan pathogen Trypanosoma cruzi revealed that the diploid genome contains a predicted 22,570 proteins encoded by genes, of which 12,570 represent allelic pairs. Over 50% of the genome consists of repeated sequences, such as retrotransposons and genes for large families of surface molecules, which include trans-sialidases, mucins, gp63s, and a large novel family (>1300 copies) of mucin-associated surface protein (MASP) genes. Analyses of the T. cruzi, T. brucei, and Leishmania major (Tritryp) genomes imply differences from other eukaryotes in DNA repair and initiation of replication and reflect their unusual mitochondrial DNA. Although the Tritryp lack several classes of signaling molecules, their kinomes contain a large and diverse set of protein kinases and phosphatases; their size and diversity imply previously unknown interactions and regulatory processes, which may be targets for intervention.

Validity of polygraphs.

Electrodermal Activity is extensively used for measuring human emotions. Validity and reliability have been questioned by some researchers. This paper reports on highly controlled experiments to determine the validity of electrodermal al activity for measuring human emotions. The authors were unable to determine the validity of electrodermal activity for measuring human emotions. Inter and intra subject variation was very high.

Vitality of oligozoospermic semen samples is improved by both swim-up and density gradient centrifugation before cryopreservation.

PURPOSE: To ascertain whether washing sperm from oligozoospermic and normozoospermic samples before cryopreservation improves post-thaw vitality. METHODS: Normozoospermic (n = 18) and oligozoospermic (n = 16) samples were divided into three aliquots. The first aliquot remained untreated and the second and third aliquots were subjected to the swim-up and discontinuous density gradient sperm washing techniques respectively. Vitality staining was performed, samples mixed with cryopreservation media and frozen. Spermatozoa were thawed, stained, and vitality quantified and expressed as the percentage of live spermatozoa present. RESULTS: Post-thaw vitality in untreated aliquots from normozoospermic samples (24.9% +/- 2.3; mean +/- SEM) was significantly higher (unpaired t-tests; P < 0.01) than untreated oligozoospermic samples (11.9% +/- 2.3). Post-thaw vitality was significantly higher after swim-up in normozoospermic samples (35.6% +/- 2.1; P < 0.001; one-way ANOVA) and oligozoospermic samples (27.7% +/- 1.7; P < 0.01). Density gradient centrifugation significantly improved post-thaw vitality in oligozoospermic (22.4% +/- 1.0; P < 0.01) but not normozoospermic (30.8% +/- 1.8) samples. CONCLUSIONS: Sperm vitality in cryopreserved oligozoospermic samples was improved by both the swim-up and density gradient centrifugation washing techniques prior to freezing.