Cryo-scanning electron microscopy (Cryo-SEM) of semen frozen in medium-straws from good and sub-standard freezer AI-boars

A major limiting factor for commercial cryopreservation of boar semen for artificial insemination (AI) is the large individual variation to cooling, where the degree of cell dehydration during ice (re)shaping seems to play a major role. This study investigated, in the frozen state, the degree of dehydration and ice crystal distribution in boar semen doses whose spermatozoa displayed different viability after thawing. Cross-sectioned medium-straws (0.5 mL, n=10) from a total of 10 stud boars classified as "good"(n=5) or sub-standard (e.g., "bad" freezers, n=5) by conventional analyses (computer assisted motility and sperm viability) were examined by Cryo-scanning electron microscopy (Cryo-SEM) to determine whether differences between groups could be already distinguishable prior to thawing. The degree of hydration was monitored in relation to the areas of ice crystal formed extracellularly (lakes), the areas of frozen, concentrated extender (veins) where spermatozoa were located and the degree of compartmentalization (number of lakes) present. Irrespectively of the region studied, the gradient of main dehydration (as lakes) observed along the cross-section area of the straws was very irregular. Most spermatozoa were enclosed in the freezing extender matrix and no obvious signs of external membrane damage were observed. None of the Cryo-SEM variables significantly correlated with post-thaw sperm parameters (p>0.05). However, we identified significant differences (p<0.0001) among boars for all ultrastructure variables studied, including the size of the veins, where differences in solute concentration is expected. We concluded that despite the large variability in ice crystal formation during the conventional freezing process among boars, this is unrelated to inter-boar post-thaw sperm differences.

Is there any association between nek3 and cancers with frequent 13q14 deletion?

Chromosomal region 13q14 is frequently deleted in prostate cancer. nek3, a protein kinase related gene, is located on this region. Analysis of the coding region of nek3 showed an A insertion/deletion polymorphism in a stretch of adenines at the end of exon 9, with 2 alleles showing either 7 or 8 adenines. In addition we found a variant human NEK3 transcript, which lacks the entire exon 10 due to alternative splicing. The frequency of A8 allele is statistically higher in prostate cancer samples (p < 0.001) than normal controls, indicating that tumor samples preferentially express a full length protein. On the contrary, normal samples have a higher frequency for the A7 allele, expressing preferentially a shorter protein. To test if this association is a common feature in cancers with frequent 13q14 alterations, we analyzed cell lines established from oral, lung, and hepatocellular cancers. An association between nek3 A insertion/deletion polymorphism and cancers with alterations at 13q14 is observed.

Personality in patients with migraine evaluated with the "Temperament and Character Inventory"

The objective of this study was to assess the personality profile of a sample of Mexican patients with migraine using the Temperament and Character Inventory (TCI). A cross-sectional study was performed including adult migraine patients identified from the outpatient neurology clinics of two large teaching hospitals in Mexico City. Patients were asked to voluntarily participate in the study. A physician conducted a standardised diagnostic interview adhering to the criteria of the International Headache Society (IHS). Patients were interviewed and administered the TCI. We used two healthy controls groups and a third group of non-migraine pain controls. One hundred and fortytwo subjects with migraine, 108 healthy blood donors, 269 young healthy controls and 30 patients with non-migraine pain (NMP) were included in the study. Patients with migraine had higher scores in the dimension harm avoidance (HA) and all its sub-dimensions (p<0.05) than healthy patients. Patients with non-migraine pain had high scores in HA and low scores in novelty seeking, self-directedness and cooperativeness. Blood donors had high scores in the following subdimensions: HA1, HA4 and C3 (Cooperativeness). Personality features consistent with migraine are avoidance, rigidity, reserve and obsessivity. Our study shows that patients with chronic pain share some of the personality features of patients with migraine but their TCI profile could be indicative of cluster C avoidant personality. Blood donors were shown to have more energy, with a tendency to help other people and be more optimistic. The results support serotoninergic involvement as explaining the physiopathology of migraine.

Genetic change in the polynesian population of Easter Island: evidence from Alu insertion polymorphisms

The origin of Pacific islanders is still an open issue in human population genetics. To address this topic we analyzed a set of 18 Alu insertion polymorphisms in a total of 176 chromosomes from native Easter Island inhabitants (Rapanui). Available genealogical records allowed us to subdivide the total island sample into two groups, representative of the native population living in the island around 1900, and another formed by individuals with some ancestors of non-Rapanui origin. Significant genetic differentiation was found between these groups, allowing us to make some biodemographic and historical inferences about the origin and evolution of this geographically isolated island population. Our data are consistent with equivalent and recent contributions from Amerindian and European migrants to the 1900s Rapanui population, with an accelerated increase in the European gene flow during the 20(th) century, especially since the 1960s. Comparative analysis of our results with other available Alu variation data on neighbouring populations supports the "Voyaging Corridor" model of Polynesian human settlement, which indicates that pre-Polynesians are mainly derived from Southeast Asian and Wallacean populations rather than from Taiwan or the Philippines. This study underlines the importance of sampling and taking into account historical information in genetic studies to unravel the recent evolution of human populations.

Tumour banks in pediatric oncology

INTRODUCTION

The information offered by the new genomic and proteomic techniques will play a central role in our knowledge of cancer; but it is limited by the lack of available tissue samples. Cancer in children is a sum of infrequent diseases, so tumor banks are support tools for translational research, providing access to a sufficiently large series of samples, which would minimize the asymmetric effect of the diverse origin.

MATERIAL AND METHODS

From 2003 a Molecular Pathology Network in Pediatric Solid Tumors Netwoks exists in Spain, and we are a part of it. Our aim was to create a pediatric tumor bank program and consensus documents about its use.

RESULTS

Standard Operating Procedures for collection and transport of samples have been created.

CONCLUSIONS

Thinking about the fast progress in Molecular Biology and the low frequency in pediatric tumors, it is vital to consider the importance of a bio bank.

Differences in SCSA outcome among boars with different sperm freezability

Spermatozoa from some boars sustain the process of cryopreservation poorly and yield poor fertility after artificial insemination. Poor freezability has not been disclosed using conventional semen analyses. A defective chromatin can, if present in a substantial number of spermatozoa, affect the fertilizing ability of spermatozoa. Here we tested the hypothesis that nuclear DNA instability could explain differences in freezability among boars, and complement or supersede conventional tests for sperm quality such as sperm motility or membrane assessments. Frozen-thawed (FT) spermatozoa from a total of 44 stud boars were assessed by the sperm chromatin structure assay (SCSA), in relation to computer-assisted sperm analysis-derived sperm motility variables and sperm viability (triple fluorescent microscopic staining), including three experiments. The first trial, including 24 boars, evaluated the relationship between the sperm motility and viability with levels of DNA integrity. The SCSA showed that most spermatozoa had intact DNA [levels of DNA fragmentation index (%DFI) ranging from 0.63% to 11.85%] significantly correlated (albeit weakly) with current sperm quality variables. The second trial, on 15 boars, assessed the influence of two different thawing rates (20 s at 37 degrees C vs. 8 s at 70 degrees C) and the post-thaw incubation times (0, 30, 150 and 300 min) at 37 degrees C on FT-boar sperm quality. The highest sperm survival (p < 0.05) and the lowest DNA damage (p < 0.01) were achieved when thawing was carried out at 70 degrees C for 8 s, without any change during the first 150 min of incubation. Finally, the third experiment studied if differences in sperm freezability showed by stud boar semen, as 'good' or 'bad' freezers by conventional analyses, could be attributed to differences in chromatin structure. All SCSA parameters were low, but significantly (p < 0.05-0.001) higher for 'bad' freezers, showing they had less homogeneous sperm chromatin than the 'good' freezers. The results indicate that SCSA outcome complements conventional assessment of FT-boar spermatozoa, disclosing differences in their ability to sustain freezing and thawing. However, the low overall DNA damage observed in FT spermatozoa seems to have poor biological significance.

Factors influencing boar sperm cryosurvival1

Optimal sperm cryopreservation is a prerequisite for the sustainable commercial application of frozen-thawed boar semen for AI. Three experiments were performed to identify factors influencing variability of postthaw sperm survival among 464 boar ejaculates. Sperm-rich ejaculate fractions were cryopre-served using a standard freezing-thawing procedure for 0.5-mL plastic straws and computer-controlled freezing equipment. Postthaw sperm motility (assessed with a computer-assisted semen analysis system) and viability (simultaneously probed by flow cytometry analysis after triple-fluorescent stain), evaluated 30 and 150 min postthaw, were used to estimate the success of cryopreservation. In the first experiment, 168 unselected ejaculates (1 ejaculate/boar), from boars of 6 breeds with a wide age range (8 to 48 mo), were cryopreserved over a 12-mo period to evaluate the predictive value of boar (breed and age), semen collection, transport variables (season of ejaculate collection, interval between collections, and ejaculate temperature exposure), initial semen traits, and sperm quality before freezing on sperm survival after freezing-thawing. In Exp. 2, 4 ejaculates from each of 29 boars, preselected according to their initial semen traits and sperm quality before freezing, were collected and frozen over a 6-mo period to evaluate the influence of interboar and intraboar ejaculate variability in the survival of sperm after cryopreservation. In Exp. 3, 12 ejaculates preselected as for Exp. 2, from each of 15 boars with known good sperm cryosurvival, were collected and frozen over a 12-mo period to estimate the sustainability of sperm cryosurvival between ejaculates over time. Boar and semen collection and transport variables were not predictive of sperm cryosurvival among ejaculates. Initial semen traits and sperm quality variables observed before freezing explained 23.2 and 10.9%, respectively, of the variation in postthaw sperm motility and viability. However, more that 70% of total variance observed in postthaw sperm quality variables among ejaculates was explained by boar. This indicates that boar is the most important (P < 0.001) factor explaining the variability among ejaculates in sperm cryosurvival, with most (14 of the 15 boars in Exp. 3) showing consistent (P > 0.05) sperm cryosurvival over time.

Further evaluation of the synthetic peptide vaccine S3Pvac againstTaenia soliumcysticercosis in pigs in an endemic town of Mexico

Taenia soliumcysticercosis is a parasitic disease frequently affecting human health and the pig industry in many developing countries. A synthetic peptide vaccine (designated S3Pvac) against porcine cysticercosis has been developed previously as an aid to interrupt transmission and has been shown to be effective. The results of the present study support the effectiveness of the vaccine under endemic field conditions. However, given the time-frame of the vaccination trial, no changes in the local levels of transmission were detectable before and after vaccination using sentinel pigs. Thus, this investigation shows the limited usefulness of single vaccination as the sole means of interruptingTaenia soliumtransmission in an endemic region.

Internally controlled real-time PCR method for quantitative species-specific detection and vapA genotyping of Rhodococcus equi

We developed a novel quantitative real-time PCR (Q-PCR) method for the soil actinomycete Rhodococcus equi, an important horse pathogen and emerging human pathogen. Species-specific quantification was achieved by targeting the chromosomal monocopy gene choE, universally conserved in R. equi. The choE Q-PCR included an internal amplification control (IAC) for identification of false negatives. A second Q-PCR targeted the virulence plasmid gene vapA, carried by most horse isolates but infrequently found in isolates from other sources. The choE-IAC and vapA assays were 100% sensitive and specific as determined using 178 R. equi isolates, 77 nontarget bacteria, and a panel of 60 R. equi isolates with known vapA+ and vapA-negative (including vapB+) plasmid genotypes. The vapA+ frequency among isolate types was as follows: horse, 85%; human, 20%; bovine and pig, 0%; others, 27%. The choE-IAC Q-PCR could detect up to one genome equivalent using R. equi DNA or 100 bacteria/ml using DNA extracted from artificially contaminated horse bronchoalveolar lavage (BAL) fluid. Quantification was linear over a 6-log dynamic range down to approximately 10 target molecules (or 1,000 CFU/ml BAL fluid) with PCR efficiency E of >0.94. The vapA assay had similar performance but appeared unsuitable for accurate (vapA+) R. equi quantification due to variability in target gene or plasmid copy number (1 to 9). The dual-reaction Q-PCR system here reported offers a useful tool to both medical and veterinary diagnostic laboratories for the quantitative detection of R. equi and (optional) vapA+ "horse-pathogenic" genotype determination.

Neuronal and smooth muscle receptors involved in the PACAP- and VIP-induced relaxations of the pig urinary bladder neck

BACKGROUND AND PURPOSE

As pituitary adenylate cyclase-activating polypeptide 38 (PACAP 38)- and vasoactive intestinal peptide (VIP) are widely distributed in the urinary tract, the current study investigated the receptors and mechanisms involved in relaxations induced by these peptides in the pig bladder neck.

EXPERIMENTAL APPROACH

Urothelium-denuded strips were suspended in organ baths for isometric force recordings and the relaxations to VIP and PACAP analogues were investigated.

KEY RESULTS

VIP, PACAP 38, PACAP 27 and [Ala(11,22,28)]-VIP produced similar relaxations. Inhibition of neuronal voltage-gated Ca(2+) channels reduced relaxations to PACAP 38 and increased those induced by VIP. Blockade of capsaicin-sensitive primary afferents (CSPA), nitric oxide (NO)-synthase or guanylate cyclase reduced the PACAP 38 relaxations but failed to modify the VIP responses. Inhibition of VIP/PACAP receptors and of voltage-gated K(+) channels reduced PACAP 38 and VIP relaxations, which were not modified by the K(+) channel blockers iberiotoxin, charybdotoxin, apamin or glibenclamide. The phosphodiesterase 4 inhibitor rolipram and the adenylate cyclase activator forskolin produced potent relaxations. Blockade of protein kinase A (PKA) reduced PACAP 38- and VIP-induced relaxations.

CONCLUSIONS AND IMPLICATIONS

PACAP 38 and VIP relax the pig urinary bladder neck through muscle VPAC(2) receptors linked to the cAMP-PKA pathway and involve activation of voltage-gated K(+) channels. Facilitatory PAC(1) receptors located at CSPA and coupled to NO release, and inhibitory VPAC receptors at motor endings are also involved in the relaxations to PACAP 38 and VIP, respectively. VIP/PACAP receptor antagonists could be useful in the therapy of urinary incontinence produced by intrinsic sphincter deficiency.

Reversal of anorexia with megestrol acetate (MA): Impact on quality of life (QoL) in non-metastasic lung cancer patients (pts) undergoing radiation therapy

18613

Background: Anorexia is a common and major problem in cancer patients. Its ethiology is multifactorial and has negative effects on pts QoL. Up to 30% of non-metastasic lung cancer pts receiving radiotherapy will develop anorexia during treatment. We conducted a randomized trial comparing the efficacy of two different doses of MA. The results of the first 130 pts included, presented at ASCO 2003, indicated that MA at doses of 600 mg/day is significantly more effective in the treatment of anorexia in these pts than low doses (320 mg/day) of MA. Here we present the results of the quality of life sub-study which purpose is to evaluate the effect of reversing anorexia in pts health related quality of life (HRQOL). Methods: From February 1999 to April 2003, 160 non-mestastatic lung cancer pts who developed anorexia during radiotherapy were randomized to receive either 320 mg/day or 600 mg/day of MA. All pts who developed anorexia filled up the EuroQuol (EQ-5D) quality of life questionnaire before treated with MA and the responders did it again when appetite was regained. The endpoint was improvement in pts HRQOL (defined as an increase > 5 mm in the EQVAS score between the second and first questionnaires). Results: The analysis of the EuroQuol (EQ-5D) questionnaires of the 131 pts who responded to treatment with MA shows that 106 pts (81%) had an improvement > 5 mm in the EQVAS score while 19 % did not. The difference is statistically significant (Binomial test: p < 0.0001). Regarding differences between the two series, 42 pts improved in the 320 mg arm versus 64 in the 600 mg arm which is not statistically significant (Fisher test: p = 0.501). Conclusions: Our results indicate that reversal of anorexia with MA has a clinically significant improvement in HRQOL in non-metastatic lung cancer pts undergoing radiation therapy. The absence of statistically significant differences between the two series may be due to the sample size.

[Table: see text]

No significant financial relationships to disclose.

A microarray-based detection system for genetically modified (GM) food ingredients

A multiplex DNA microarray chip was developed for simultaneous identification of nine genetically modified organisms (GMOs), five plant species and three GMO screening elements, i.e. the 35S promoter, the nos terminator and the nptII gene. The chips also include several controls, such as that for the possible presence of CaMV. The on-chip detection was performed directly with PCR amplified products. Particular emphasis was placed on the reduction of the number of PCR reactions required and on the number of primers present per amplification tube. The targets were biotin labelled and the arrays were detected using a colorimetric methodology. Specificity was provided by specific capture probes designed for each GMO and for the common screening elements. The sensitivity of the assay was tested by experiments carried out in five different laboratories. The limit of detection was lower than 0.3% GMO for all tests and in general around 0.1% for most GMOs. The chip detection system complies with the requirements of current EU regulations and other countries where thresholds are established for the labelling of GMO.

Long term NSAID treatment inhibits COX-2 synthesis in the knee synovial membrane of patients with osteoarthritis: differential proinflammatory cytokine profile between celecoxib and aceclofenac

OBJECTIVE

To compare the effect of celecoxib with that of a classic non-steroidal anti-inflammatory drug (NSAID) on synovial inflammation and on the synovial expression of proinflammatory genes in patients with knee osteoarthritis (OA).

METHODS

30 patients with severe knee OA scheduled for total knee replacement surgery were included in a 3 month clinical trial. They were randomised to two groups: patients treated with celecoxib (CBX) (200 mg/24 h) and patients treated with aceclofenac (ACF) (100 mg/12 h). Those patients with OA who did not want to be treated with NSAIDs served as a control group. During knee surgery, synovial fluid (SF) and synovial membrane (SM) were collected. A SM specimen was fixed and embedded in paraffin and another part was frozen for molecular biology studies.

RESULTS

At the end of study both CBX and ACF treated patients showed a significant improvement in pain and knee function compared with controls. Both drugs significantly reduced prostaglandin E(2) (PGE(2)) SF concentration and down regulated COX-2 mRNA and protein expression at the SM. However, synovial macrophage infiltration (CD68 antigen staining) and expression of proinflammatory mediators, such as interleukin 1beta and tumour necrosis factor alpha, were decreased only by CBX treatment.

CONCLUSION

Both drugs improved joint pain and function, inhibited SF PGE(2) concentration, and induced a decrease in synovial COX-2 expression and synthesis not related to the tissue inflammatory status. These data suggest that PGE(2) blocking agents may decrease PGE(2) production not only by direct COX-2 inhibition but also by down regulating COX-2 expression and synthesis. However, CBX and ACF appear to have different anti-inflammatory profiles in controlling OA synovial macrophage infiltration and proinflammatory expression.

Dissimilarities in sows’ ovarian status at the insemination time could explain differences in fertility between farms when frozen-thawed semen is used

Deep intrauterine insemination (DUI) offers a suitable alternative for the commercial use of frozen-thawed boar semen. The present study evaluated how the ovarian status at DUIs of frozen-thawed spermatozoa (1 x 10(9) spz/dose, two DUIs, 30-31 and 36-37 h after detection of oestrus) in 179 sows would explain differences in fertility between two farms with similar, but not equal, reproductive management (experiment 1). A further experiment investigated whether an increase in sperm number per AI-dose (1 versus 2 x 10(9) spz/dose, two DUIs, 30-31 and 36-37 h after detection of oestrus, on 228 sows) could minimize this effect (experiment 2). Ovaries were checked by transrectal ultrasonography at the time of DUI and sows were classified into three categories: F-: ovarian pre-ovulatory follicles were visible during two examinations; O-: ovulation visible during one examination; and C-sows: corpora hemorragica visible during the two examinations. Overall farrowing rates differed (P < 0.01) between farms (70.1 versus 51.2%, farms A and B, respectively). Distribution of sows among ultrasonography categories also differed (P < 0.05) between farms (17.5, 72.2 and 10.3% were classified as F-, O- and C-sows in farm A, versus 40.2, 29.3 and 30.5% in farm B). Nevertheless, farrowing rates and litter sizes within categories did not vary between farms (P > 0.05). In addition, a two-fold increase in the number of spermatozoa per DUI improved (P < 0.05) fertility in F- and C-sows, but not in O-sows. In conclusion, the interval DUI-to-ovulation provides a major explanation for fertility differences between farms when frozen-thawed spermatozoa are used.

Strategies to improve the fertility of frozen-thawed boar semen for artificial insemination

Although cryopreservation of boar semen for artificial insemination (AI) was developed 35 years ago, cryopreservation conditions and AI strategies are still considered sub-optimal. AI with excessive numbers of frozen-thawed sperm (5-6 x 10(9) cells), still does not achieve fertility levels similar to AI using liquid semen because of reduced sperm survival. Frozen-thawed (FT) spermatozoa have therefore not been the preferred option for commercial breeding programmes. However, substantial progress has been made regarding boar sperm cryopreservation. Adjustment of cooling and re-warming rates to biophysical properties of boar spermatozoa, new sperm package systems and the achievement of accurately consistent freezing of large numbers of samples using programmable freezers have contributed to post-thaw survival rates above 50%, a threshold similar to that used for bull AI-semen. Moreover, these post-thaw sperm survival rates are consistent within a large population of boars selected for sperm freezability potential, as occurs with AI-bull sires. When such post-thaw boar semen is deposited intra-utero, acceptable fertility (in terms of farrowing rates and litter size) is obtained. Currently, the most effective application of FT-semen for AI is achieved using deep uterine-AI (DUI) which allows placement of a minimal semen dose (in volume 0.5 to 10 mL and sperm number 0.5 to 1 x 10(9) total spermatozoa) into the anterior 1/3 of one uterine horn, with levels of fertility close to AI with liquid semen. However, owing to their shorter life span, FT-boar spermatozoa require an AI-to-ovulation interval not longer than 4-6 h, making peri-ovulatory AI a pre-requisite to obtain the highest possible fertility. Spontaneous ovulation most often occurs when two-thirds of oestrus has passed. Estimation of the duration of oestrus, taking into account the weaning-to-oestrus interval, is helpful when establishing appropriate AI-schedules. However, as the length of oestrus varies within and between farms, different AI strategies should be established a priori. The development of bio-sensors for spontaneous ovulation will widen the use of AI with frozen-thawed frozen semen.

[Cardiac and vascular homograft valves transplant]

The advances in the manipulation of human tissues, the development of cryobiology, paediatric cardiac surgery, the impossibility of obtaining an ideal prosthetic cardiac valve and the surgical treatment of cardiovascular infections have revived interest in the use of homografts. The donors of these homografts can be: a) Live donors: aortic and pulmonary valve of the recipient of a heart transplant; b) Multiorgan donors with a diagnosis of death according to neurological criteria, whose heart is rejected for heart transplant; c) Cadaver donors with asystolia of less than 8 hours. Homograft cardiac valves are the substitute of choice in aortic valve endocarditis, patients with counter-indications for anticoagulation, reconstruction of the outflow tract of the right ventricle, aortic valve replacement in children and young adults through the Ross operation, and an optional indication is the aortic valve and/or rising aorta replacement in patients over 60 years of age. Although there are not sufficiently broad series of homogratfs with arterial substitutes, with respect to the number of patients and time of evolution, the results suggest that this can benefit patients with vascular infection, immunodepressed patients or complex patients whose technique during the operation might require a homograft.

97 DIFFERENCES IN SPERM CHROMATIN STRUCTURE AMONG GOOD AND BAD BOAR SPERM FREEZERS

Inter- and intra-boar differences in sperm freezability are observed independent of the sperm quality before freezing, the breed, or the genetic line. This study aimed to determine whether boars with different post-thaw sperm quality also show differences in sperm DNA integrity. Sperm-rich fractions (3 to 10 ejaculates per boar) from 19 fertile mature boars were extended in Beltsville thawing solution (BTS) and cooled to 17�C for 16 h. Then, samples were centrifuged at 2400g for 3 min, extended in freezing extender (lactose/egg yolk/glycerol/Equex STM; Nova Chemical Sales, Inc., Scituate, MA, USA) to a final concentration of 1 � 109 spermatozoa/mL, dispensed into 0.5 mL straws, and frozen in a programmable cell freezer at a rate of -20�C min. Thawing was carried out in a water bath at 37�C for 20 s. Frozen-thawed spermatozoa were evaluated for progressive sperm motility (PSM) using a computer-assisted sperm analysis (CASA) system, and sperm viability (PMI) using flow cytometry. All data generated were used for a multivariate pattern analysis (PATN; CSIRO, Canberra, Australia) which objectively classified all boars into two groups, categorized as good (n = 10; >60% PSM and PMI) or bad (n = 9; <40% PSM and PMI) based on their sperm freezability. Post-thaw sperm quality was consistent for different ejaculates within boars (P < 0.05). The DNA-integrity of frozen-thawed spermatozoa was evaluated according to the sperm chromatin structure assay (SCSA; Evenson et al. 1980 Science 210, 1131-1133). All SCSA variables (X mean, DNA fragmentation index (DFI), and the standard deviation of the DFI), were significantly higher for bad freezers (P < 0.001). The percentage of spermatozoa with abnormal chromatin structure ranged from 1.06 to 3.42% for good and 3.06 to 6.04% for bad freezers. Although these differences exist between good and bad sperm freezers, and can only to some extent be the product of cryopreservation, the levels of affected spermatozoa can not explain the differences on post-thaw sperm survival seen in the two categories of sires. This work was supported by CICYT, AGL05-0471 (Spain), SLF and Formas (Sweden).