Strategies to Reduce the Use of Antibiotics in Fresh and Chilled Equine Semen

The study assessed the impact of four equine semen processing techniques on sperm quality and microbial load immediately post-processing and after 48 h of refrigeration. The aim was to explore the potential reduction of prophylactic antibiotic usage in semen extenders. Semen from ten adult stallions was collected and processed under a strict hygiene protocol and divided into four aliquots: Simple Centrifugation with antibiotics (SC+), Simple Centrifugation (SC-), Single-Layer Colloidal Centrifugation (CC-), and Filtration (with SpermFilter®) (F-), all in extenders without antibiotics. Sperm motility, viability, and microbial load on three culture media were assessed. No significant differences were observed in the main in the sperm quality parameters among the four protocols post-processing and at 48 h (p < 0.05 or p < 0.1). Microbial loads in Columbia 5% Sheep Blood Agar and Schaedler vitamin K1 5% Sheep Blood Agar mediums were significantly higher (p < 0.10) for raw semen than for CS+, CC-, and F- post-processing. For Sabouraud Dextrose Agar medium, the microbial load was significantly higher (p < 0.10) in raw semen compared to CS+ and F-. No significant differences (p < 0.10) were found in 48 h chilled samples. Regardless of antibiotic presence, the evaluated processing methods, when combined with rigorous hygiene measures, maintained semen quality and reduced microbial load to the same extent as a traditional protocol using antibiotics.

Optimization of the Equine-Sperm Freeze Test in Purebred Spanish Horses by Incorporating Colloidal Centrifugation

The Purebred Spanish Horse, according to our clinical experience, is characterized by having a high number of stallions that do not meet the international commercial recommendations for equine-sperm cryopreservation. This means that artificial insemination with frozen semen from these stallions is less widespread than in other breeds. In this study, we investigated if the incorporation of single-layer colloidal centrifugation prior to cryopreservation in clinical conditions could increase the number of ejaculates of Purebred Spanish stallions suitable for this processing, observing the influence of centrifugation and freezing extender protocol on post-thawed sperm motility. Using colloidal centrifugation, the percentage of ejaculates available to be frozen was increased from 35% (6/17) to 71% (12/17), doubling the number of samples that could have been subjected to cryopreservation. We only found significant differences in linearity (LIN) and lateral head displacement (ALH) after 5 min of incubation at 37 °C between colloidal and simple centrifugation processing techniques. No significant differences were found between the two different colloidal protocols in any of the variables considered. Colloidal centrifugation allowed us to obtain, from worse fresh-quality ejaculates, thawed sperm doses with similar quality to that of good-quality ejaculates. BotuCrio^® produced, in general, higher motility parameters and its characteristics than the other extenders analyzed, with significant differences found in comparison to Inra-Freeze^® and Lac-Edta in both total (MOT) and progressive motility (PMOT) when using colloidal centrifugation and only in PMOT when applying simple centrifugation. Colloidal centrifugation optimized the efficiency of cryopreservation, as it allowed us to increase the number of ejaculates of Purebred Spanish Horses suitable to be frozen. Including these semen processing techniques in the freeze test could help to optimize equine-sperm cryopreservation protocols, especially when dealing with individuals or breeds for which initially low sperm quality prevents or limits their inclusion in sperm cryopreservation programs.

PSIX-8 Supplementing a Natural Citrus Flavonoid Extract (Bioflavex) to Finishing Cattle

Finishing cattle are exposed to diets with high amounts of starch and consequently to hindgut acidosis. Usually, antibiotics like ionophores are used to control dysbiosis at gut level. However, natural options are being evaluated as healthy alternatives. Flavonoids are well known as antibacterial agent, being an interesting alternative to antibiotics. The aim of this experiment was to evaluate the performance of finishing steers supplemented with monensin compared with citrus flavonoid extract (Bioflavex). Steers (n = 48; 214.3 kg live weight; LW) were assigned to two treatments: Monensin (MON; 30 g/tn DM) and flavonoids extract (FLAV; Bioflavex, Spain; 400 g/tn DM). Animals were allocated in 6 groups (3 pens/treatment; 8 animals/pen). Pen was considered as the experimental unit. Transition diet was offered from d 1 to 21 (CP 18% , starch 40.6%) whilst finishing diet from d 21 to 86; (CP 10.6%, starch 47.8%). The LW was registered at 0, 21 and 86 d. The DMI was estimated by difference between offered and refusals. Ruminal and feces pH were recorded (rumen liquor samples were obtained by ruminocentesis). Data were analyzed by proc mixed (treatment and time as fixed effects; pen as random). Differences were stated when P&lt; 0.05. Only DMI was different between treatments, being FLAV greater than MON (6.68 kg/d vs 6.45 kg/d for FLAV and MON respectively; P&lt; 0.05). No differences were found in terms of daily gain (1.355 kg/d vs 1.294 kg/d for FLAV and MON respectively; P &gt;0.05), final weight (FLAV 331.6 kg vs MON 324.8 kg; P &gt;0.05), neither conversion (4.95 kg/kg vs 4.98 kg/kg for FLAV and MON respectively; P &gt;0.05). Rumen and feces pH did not differ across treatments (P &gt;0.05). According to our results, a citrus flavonoid extract showed a similar performance comparing to monensin, being a potential alternative to antibiotics.

Situated transdisciplinarity in university policy: lessons for its institutionalization

Although transdisciplinarity has taken hold in many areas, it is still a concept in its early stages of development in Latin America. We see an emergent opportunity to contribute to the current discussion on transdisciplinarity and its institutionalization at universities. Our specific interest in this paper is to disentangle the conditions under which transdisciplinarity is developed in Latin American contexts and how it can be better implemented within those contexts. Our study focuses on the context of "Latin American Public Universities." We examine the following research questions: (i) How is transdisciplinarity conceptualized in university policy and what are the conditions for its institutionalization? (ii) What lessons can be drawn more broadly from the role of university policy in the process of institutionalizing transdisciplinarity? To address these questions, we take the Universidad de Chile as a case study and apply a qualitative methodology of content analysis of university policy documents in the period 2006-2021. Grounded on empirical data, we elaborate on the concept of "situated transdisciplinarity" that emerges from the interplay between practices and policy at the Universidad de Chile and serves as a tool for future institutionalizing processes. We conclude that the concept of "situated transdisciplinarity" can orient transdisciplinary research policy, by problematizing discourses and perceptions.

Characterization of the seminal bacterial microbiome of healthy, fertile stallions using next-generation sequencing

High-throughput sequencing studies have shown the important role microbial communities play in the male reproductive tract, indicating differences in the semen microbial composition between fertile and infertile males. Most of these studies were made on human beings but little is known regarding domestic animals. Seminal bacteria studies made in stallions mostly focus on pathogenic bacteria and on their impact on reproductive technology. However, little is known about stallion commensal seminal microflora. That ultimately hinders our capacity to associate specific bacteria to conditions or seminal quality. Therefore, the aim of this study was to characterize the seminal microbial composition of 12 healthy, fertile stallion using next-generation sequencing. Hypervariable region V3 was chosen for bacterial identification. A total of nine phyla was detected. The most abundant ones were Bacteroidetes (46.50%), Firmicutes (29.92%) and Actinobacteria (13.58%). At family level, we found 69 bacterial families, but only nine are common in all samples. Porphyromonadaceae (33.18%), Peptoniphilaceae (14.09%), Corynebacteriaceae (11.32%) and Prevotellaceae (9.05%) were the most representative ones, while the Firmicutes phylum displayed the highest number of families (23, a third of the total). Samples showed high inter-subject variability. Findings previously described in other species notably differ from our findings. Families found in human such as Lactobacillaceae, Staphylococcaceae and Streptococcaceae only represented a 0.00%, 0.17% and 0.22% abundance in our samples, respectively. In conclusion, Porphyromonadaceae, Prevotellaceae, Peptoniphilaceae and Corynebacteriaceae families are highly represented in the seminal microbiome of healthy, fertile stallions. A high variation among individuals is also observed.

Effect of season on individual stallion semen characteristics

Horses are long-day seasonal breeding animals, however, with modern stallion reproductive management it is important for collection of semen during periods that are not part of the traditional breeding season. This study was conducted to examine variation in the seminal characteristics of individual stallions in Avila, Spain during 1 year with a particular emphasis on sperm DNA fragmentation. Semen was collected twice per season from a total of 20 stallions. There was a marked seasonal effect on all seminal characteristics, with the greatest on progressive motility, % membrane integrity and least for SDF in the spring months; there was also an interaction effect with respect to individual stallion, indicating that some stallions did not fit this generalised pattern for semen quality. Sperm DNA fragmentation was assessed both immediately after semen collection (T0) and following incubation of extended semen for 24 h (T24) to broadly mimic changes in SDF that might occur in the female reproductive tract. While SDF evaluated at T0 was also generally less in spring, the proportion of stallions with the least SDF values in spring increased from 45% to 60% when assessed at T24, therefore, being consistent with the importance of dynamic SDF assessment in detecting DNA damage that was not detected at T0 or cryptic DNA damage. The results from this study indicate there is individual seasonal variation among stallions in all aspects of seminal characteristics; such variation needs to be considered when prioritising stallions that are to be used for breeding.

Fertilizing capacity of vitrified stallion sperm assessed utilizing heterologous IVF after different semen warming procedures

The aim of this study was to evaluate the fertilizing capacity of frozen or vitrified stallion sperm after assessing different warming procedures. In Experiment 1, different warming procedures were compared after sperm vitrification: immersion in extender at 43 °C (C), or in a water bath at 37 °C/30 s (W37), 43 °C/10 s (W43) or 60 °C/5 s (W60). With the W60 treatment, there were greater values (P < 0.05) for VCL (83.93 ± 3.6 μm/s) and ALH (3.00 ± 0.2 μm) than freezing and with the C group, and greater values (P < 0.001) for PM (35.33 ± 2.5 %) than with the W43 treatment. In Experiment 2, the fertilizing capacity of vitrified and frozen sperm was assessed utilizing heterologous IVF procedures, using cattle oocytes. Vitrification resulted in greater values (P < 0.05) than freezing for the number of bound sperm (1.36 ± 0.3 and 0.69 ± 0.2, respectively). There were no differences between frozen or vitrified sperm in pronuclear formation (26 hours post-insemination - hpi; 14.08 ± 4.2 % and 22.78 ± 4.8 %, respectively) or cleavage rate (32.77 ± 4.3 % and 39.66 ± 4.6 %, respectively). In conclusion, vitrified stallion sperm warmed in a water bath at 60 ºC had the capacity to penetrate cattle oocytes, leading to pronuclear formation and hybrid embryo cleavage after heterologous IVF.

Low-density lipoproteins and milk serum proteins improve the quality of stallion sperm after vitrification in straws

Lipids and proteins can be used for sperm vitrification to preserve the integrity of sperm membranes or to increase the viscosity of the medium. This study evaluated the effect of low-density lipoproteins (LDL) and milk serum proteins (Pronexcell) for stallion sperm vitrification. Hippex extender (Barex Biochemical Products, The Netherlands), plus 1% of bovine serum albumin and 100 mM of trehalose, was used as control for sperm vitrification. In experiment 1, different concentrations of LDL (L1 = 0.25, L2 = 0.5, L3 = 1%) and in experiment 2 of Pronexcell (P1 = 1, P2 = 5, P3 = 10%) were added to control extender. Vitrification was performed in 0.25-ml straws directly plunged into liquid nitrogen. Total motility (TM, %) and progressive motility (PM, %) were analysed by CASA, and plasma membrane (IMS, %) and acrosome membrane integrity (AIS, %) were assessed under epifluorescence microscopy. Post-warmed sperm parameters were compared between treatments by ANOVA. Results were expressed as mean ± SEM. In both experiments, the minimum concentration of LDL and Pronexcell obtained significantly higher values (p < 0.01) than the control extender for TM (L1 = 52.95 ± 4.4; P1 = 58.99 ± 4.6; C = 30.88 ± 3.0), PM (L1 = 36.79 ± 5.5; P1 = 47.25 ± 4.3; C = 19.20 ± 2.4), IMS (L1 = 68.88 ± 3.6; P1 = 47.25 ± 4.3; C = 52.81 ± 2.6) and AIS (L1 = 45.88 ± 3.6; P1 = 47.25 ± 4.3; C = 26.00 ± 2.1). No differences in sperm parameters were found among different concentrations of LDL or Pronexcell. In conclusion, the addition of 0.25% LDL and 1% Pronexcell to the vitrification extender is recommended to improve the quality of stallion sperm after vitrification.

Comparison of different mathematical models to assess seasonal variations in the longevity of DNA integrity of cooled-stored stallion sperm

Dynamic assessment of sperm DNA fragmentation (SDF) has shown to give fuller understanding of stallion semen quality; however, there have been limited attempts to use this parameter to investigate seasonal changes in productive functions. The aims of this study were to: (a) establish a reliable mathematical model to describe the longevity of cooled-stored sperm DNA integrity; (b) to examine the effect of seasonal variations on SDF. Ejaculates were cooled to 5°C, and SDF was analysed after 0, 6 and 24 hr of storage. The coefficient of determination (R² ) was calculated after fine-tuning linear (LIN), exponential (EXP) and second order polynomial (POL) models. R² was significantly higher (p < .001) for POL than for LIN and EXP. The rate of DNA degradation was calculated using the slopes of POL equations. After assessing the rate of change of the POL functions, significant differences between the acceleration of DNA fragmentation were found (p < .01) among seasons, being higher for winter and summer than spring and autumn. In conclusion, DNA analysis of stallion sperm fits better to a second order polynomial mathematical model, being spring the best season to collect and process cooled stallion semen in order to maintain the DNA integrity of the stallion sperm.

Seasonal variations in sperm DNA fragmentation and pregnancy rates obtained after artificial insemination with cooled-stored stallion sperm throughout the breeding season (spring and summer)

The aim of this study was to assess seasonal variations during different periods of the breeding season (spring and summer) on stallion sperm DNA fragmentation and in vivo fertility associated with cooled-stored semen samples. Ejaculates were collected from eleven stallions and assessed for sperm motility (assessed by computer-assisted sperm analysis) and plasma membrane integrity (evaluated under fluorescence microscopy). Sperm DNA fragmentation (evaluated by the Sperm Chromatin Dispersion test) was assessed in cooled-stored semen at 5 °C for up to 24 h. Artificial insemination was performed throughout the breeding season. Mares were inseminated with cooled-stored semen (up to 24 h) every other day until ovulation. Pregnancy rates per cycle were determined detecting the embryonic vesicle by ultrasonography fifteen days after ovulation. Values (mean ± SD) for progressive sperm motility were significantly higher (P < 0.05) in spring (53.57 ± 9.97%) in comparison to summer (41.37 ± 10.81%). No significant differences in plasma membrane integrity were found between seasons (P > 0.05). Sperm DNA fragmentation was significantly lower (P < 0.01) in spring in comparison to summer after 0h (4.81 ± 1.87% vs. 8.77 ± 5.78%), 6h (9.00 ± 3.19% vs. 18.73 ± 8.22%) and 24h (14.6 ± 4.13% vs. 30.14 ± 9.85%) of cooled-storage. Pregnancy rates per cycle were also significantly higher (P < 0.01) in spring (50%) in comparison to summer (37%). There was a moderate negative relationship between positive pregnancies and sperm with fragmented DNA (r = - 0.619; P < 0.001). Semen samples associated with moderate fertility levels (Pregnancy rate < 50%) showed a higher percentage of sperm with fragmented DNA compared to samples obtaining higher fertility levels. In conclusion, seasonal variations were found during the breeding season, obtaining lower sperm DNA fragmentation and higher pregnancy rates in spring. Additionally, samples with the highest proportion of sperm with fragmented DNA showed the lowest fertility levels throughout the breeding season.

Vitrification of stallion sperm using 0.25 ml straws: Effect of volume, concentration and carbohydrates (sucrose/trehalose/raffinose)

Sperm vitrification is a rapid freezing method in which carbohydrates are used as cryoprotectants. The aim of this study was to determine the optimal volume, concentration and type of carbohydrates for stallion sperm vitrification using 0.25 ml straws in comparison to conventional freezing. Ejaculates (n = 54) were collected from six stallions. For vitrification, straws were filled with different volumes (30, 70, 100 μl), sperm concentrations (50, 100, 200 × 10⁶ sperm/ml) and extenders containing sucrose (20, 100, 200 mM), trehalose (50, 100, 200 mM) and raffinose (50, 100, 200 mM) and plunged into LN₂. Conventional freezing was performed in 0.5 ml straws frozen in LN₂ vapors. Sperm motility, plasma and acrosome membrane integrities and DNA fragmentation were compared among treatments. The use of straws filled with 100 μl at 100 × 10⁶ sperm/ml with the extender containing 100 mM trehalose resulted in greater values for sperm quality than the other concentrations, volumes and carbohydrates. With vitrification, there were greater values (mean ± SEM; P < 0.05) than freezing for progressive motility (48.2 ± 2.3 compared with 37.3 ± 2.2%), plasma membrane integrity (82.8 ± 1.5 compared with 74.1 ± 1.9%), and intact acrosomes (50.2 ±  1.2 compared with 43.1 ± 1.4%); and less DNA fragmentation (6.4 ± 0.7 compared with 8.2 ± 0.3%). In conclusion, stallion sperm can be vitrified in 0.25 ml straws filled with 100 μl of sperm at 100 x 10⁶ sperm/ml using an extender with 100 mM of trehalose, obtaining better sperm quality after warming than conventional freezing.

Effect of sperm dosage transportation in stallions: Effect on sperm DNA fragmentation

Artificial insemination programs for horses usually involve ex vivo handling and transporting of sperm. The present experiment was designed to: (i) assess the effect of transportation on sperm DNA integrity at different time post semen collection, and (ii) evaluate if sperm DNA quality deteriorates rapidly beyond 24 h of cooled storage. After collection, the ejaculates were extended using INRA 96 and semen was prepared for prompt analysis (A0) or 24 h/48 h cooled-shipping (B24 and C48 respectively). Each sample was assessed for sperm DNA fragmentation index (SDFI) at time 0 and after incubation for 2, 6 and 24 h at 37 °C. There was very little difference in SDFI between freshly extended (A0) and 24 h/48 h cooled-transported semen samples (B24/C48) at time 0. After 2 h of incubation at 37 °C, there was an increase in SDFI ranging from 2.7% to 7.5% per hour in freshly extended semen samples (A0: 5.1 ± 1.5), while cooled-transported semen samples had a much greater increase in SDFI, ranging from 5.0% to 20.5% (B24: 14.7 ± 5.6) and from 8.2% to 26.8% (C48: 18.3 ± 7.2) respectively. There were not marked differences in the sperm DNA integrity between 24 and 48 h for transported samples, thus there is the possibility of desirable fertility with use of stallion sperm after 48 h of cooled storage.

Vitrification of Large Volumes of Stallion Sperm in Comparison With Spheres and Conventional Freezing: Effect of Warming Procedures and Sperm Selection

Stallion sperm was vitrified using straws in comparison with spheres and conventional freezing. Vitrification was performed plunging 30 μL of sperm (spheres) or 0.5 mL straws into liquid nitrogen (LN₂) and conventional freezing using 0.5 mL straws frozen in LN₂ vapors. Sperm vitrified in straws were submitted to different warming procedures (42°C/20 seconds; 60°C/15 seconds) and single-layer centrifugation (SLC). Total (TM, %) and progressive sperm motility (PM, %), plasma membrane (IMS, %) and acrosome integrity (AIS, %) were statistically compared between treatments (mean ± SEM). Significant higher values (P < .001) were obtained after vitrification using spheres in comparison with conventional freezing and vitrification in straws for TM (54.46 ± 3.2 vs. 36.47 ± 3.2 vs. 2.50 ± 1.2, %), PM (38.63 ± 3.4 vs. 15.11 ± 2.0 vs. 1.9 ± 0.9, %), IMS (65.40 ± 2.8 vs. 50.50 ± 2.8 vs. 21.63 ± 2.1, %), and AIS (48.89 ± 2.8 vs. 15.46 ± 1.7 vs. 4.69 ± 0.9, %). No differences were found between warming procedures. Single-layer centrifugation after warming at 42°C/20 seconds obtained higher values (P < .05) than unselected samples for TM (32.52 ± 5.8%), PM (14.22 ± 2.8%), IMS (60.01 ± 3.2%), and AIS (44.5 ± 2.2%), whereas selection after 60°C/15 seconds increased TM (23.11 ± 4.3%) and IMS (67.11 ± 3.9%). In conclusion, vitrification in spheres obtained better sperm quality than conventional freezing and vitrification in straws. Warming procedures did not affect the sperm quality but SLC could be a strategy to enhance the quality of the samples after sperm vitrification using 0.5 mL straws.

Identification of Three Novel Mutations in Hereditary Protein S Deficiency

We report the application of single-stranded conformation polymorphism (SSCP) analysis to the screening of 15 functionally important Protein S (PS) gene (PSα) regions (4.243 Kb) in 6 unrelated families with PS deficiencies. Direct sequencing of the fragments with altered migration patterns led to the identification of the corresponding molecular alterations. A missense mutation, G to T transversion at codon Cys598, and two different alterations, leading either to allelic exclusion, or premature termination of the protein translation: a G to A transition at codon Trp465 and a 1 nt (T) insertion at codon 265, were identified. The 1 nt insertion was observed in three apparently unrelated families but with a common geographical origin and the mutated allele was undetectable in platelet mRNAs of affected individuals. Family analysis confirmed, in each case, a perfect cosegregation of the mutation with the PS deficiency. We conclude that these alterations represent the causative mutations.

Stallion sperm selection prior to freezing using a modified colloid swim-up procedure without centrifugation

The aims of this study were to: 1) develop a new method for stallion sperm selection using a modified swim-up procedure through a colloid and 2) evaluate its impact in good quality ejaculates from bad freezers in comparison to methods involving centrifugation such as single layer centrifugation and sperm washing. Ejaculates were processed before freezing using three different procedures: sperm washing (SW), colloid single layer centrifugation (SLC) and a modified colloid swim-up (SU). After semen processing, sperm recovery rates were measured and sperm were frozen. Post-thaw sperm motility (assessed by computer-assisted sperm analysis), normal forms and plasma membrane integrity (evaluated under bright-field and fluorescence microscopy respectively), and DNA fragmentation (assessed by the Sperm-Halomax kit) were compared between treatments. Sperm recovery rates were similar between SU and SLC but lower than SW. Sperm motility after thawing was lower in SU in comparison to SLC and SW, maybe due to the incomplete removal of seminal plasma before freezing. Sperm DNA fragmentation was lower in SU and SLC selection methods, particularly in SLC selected samples during the first 6h of incubation. The remaining sperm parameters assessed were similar among treatments. In conclusion, SLC is more suitable than SW and SU to process stallion semen prior to freezing, in particular when sperm DNA damage is suspected. Further studies are needed in order to determine the potential benefits of SU in samples where centrifugation is not necessary, such as epididymal sperm, ejaculate fractioning or post-thaw semen samples.

New approach to assess sperm DNA fragmentation dynamics: Fine-tuning mathematical models

Background

Sperm DNA fragmentation (sDF) has been proved to be an important parameter in order to predict in vitro the potential fertility of a semen sample. Colloid centrifugation could be a suitable technique to select those donkey sperm more resistant to DNA fragmentation after thawing. Previous studies have shown that to elucidate the latent damage of the DNA molecule, sDF should be assessed dynamically, where the rate of fragmentation between treatments indicates how resistant the DNA is to iatrogenic damage. The rate of fragmentation is calculated using the slope of a linear regression equation. However, it has not been studied if sDF dynamics fit this model. The objectives of this study were to evaluate the effect of different after-thawing centrifugation protocols on sperm DNA fragmentation and elucidate the most accurate mathematical model (linear regression, exponential or polynomial) for DNA fragmentation over time in frozen-thawed donkey semen.

Results

After submitting post-thaw semen samples to no centrifugation (UDC), sperm washing (SW) or single layer centrifugation (SLC) protocols, sDF values after 6 h of incubation were significantly lower in SLC samples than in SW or UDC. Coefficient of determination (R²) values were significantly higher for a second order polynomial model than for linear or exponential. The highest values for acceleration of fragmentation (aSDF) were obtained for SW, followed by SLC and UDC.

Conclusion

SLC after thawing seems to preserve longer DNA longevity in comparison to UDC and SW. Moreover, the fine-tuning of models has shown that sDF dynamics in frozen-thawed donkey semen fit a second order polynomial model, which implies that fragmentation rate is not constant and fragmentation acceleration must be taken into account to elucidate hidden damage in the DNA molecule.

Equivalent seminal characteristics in human and stallion at first and second ejaculated fractions

Sperm quality was assessed in normozoospermic human (n = 10) and Spanish breed stallion (n = 10) after sperm fractionation during ejaculation. The first ejaculated fraction was separated from the second. A third sample was reconstituted using equivalent proportion of both fractions (RAW). Fraction 1, Fraction 2 and RAW semen were incubated for 30 min at 37°C to homogenise the impact of iatrogenic damage between both species. Sperm concentration, motility and sperm DNA damage were assessed in each fraction and RAW semen. The results showed two important facts: (i) spermatozoa confined at Fraction 1 exhibit superior parameters than those included at Fraction 2 in both species, and (ii) there is a certain level of concordance between species in the proportion of benefit observed when Fraction 1 is compared to RAW semen. Altogether, these results call into question whether the standard practice of whole ejaculate collection can be considered the best strategy when using male gametes for artificial insemination. In fact, the reconstituted RAW semen exhibits poorer semen characteristics than those found in Fraction 1.

Differences in preservation of canine chilled semen using simple sperm washing, single-layer centrifugation and modified swim-up preparation techniques

This study compared the efficacy of simple sperm washing (SW), single-layer centrifugation (SLC) and modified swim-up (SU) techniques in the preparation of dog spermatozoa for cooling. Eighteen ejaculates, collected from three dogs (six per dog), were pooled (three ejaculates per pool) and divided into three aliquots: (1) one aliquot was washed and cooled at 5°C for 72h, considered as control (SW-control), (2) the second aliquot was selected by SLC through Androcoll-C and subsequently cooled in the same way as the SW-control samples (SLC-AC) and (3) the last aliquot was selected by a modified SU method with Androcoll-C and cooled as mentioned above (SU-AC). Assessment of sperm motility, sperm morphology, sperm membrane integrity and acrosome integrity were performed on aliquots of fresh semen and chilled-rewarmed samples. Sperm membrane integrity and progressive motility were significantly (PPP>0.05). The recovery rates were not significantly (P>0.05) different between SW-control, SLC-AC and SU-AC samples. Our results confirm that SU-AC may be a successful method for the preparation of dog spermatozoa for cooling.

Effect of single-layer centrifugation or washing on frozen-thawed donkey semen quality: Do they have the same effect regardless of the quality of the sample?

The aims of this study were to determine the sperm quality of frozen-thawed donkey sperm samples after single-layer centrifugation (SLC) using Androcoll-E in comparison to sperm washing or no centrifugation and to determine if the effect on the sperm quality after SLC or sperm washing depends on the quality of the sample. Frozen-thawed sperm samples from Andalusian donkeys were divided into three aliquots, and they were processed using three different techniques after thawing: uncentrifuged diluted control (UDC), sperm washing (SW), and SLC. Afterward, sperm quality index was estimated by integrating all parameters (total and progressive sperm motility, membrane integrity, and DNA fragmentation) in a single value. The relationship between the sperm quality of thawed UDC samples and the effect on sperm parameters in SW and SLC-selected samples was assessed. Sperm quality index was significantly higher (P < 0.001) in SLC (0.8 ± 0.0) samples than that in UDC (0.6 ± 0.0) and SW (0.6 ± 0.0) samples, regardless of the sperm quality index after thawing of the sperm sample. In conclusion, SLC of frozen-thawed donkey spermatozoa using Androcoll-E-Small can be a suitable procedure for selecting frozen-thawed donkey sperm with better quality, in particular in those samples where an improvement in motility is needed.

Localization of alkali-labile sites in donkey (Equus asinus) and stallion (Equus caballus) spermatozoa

The presence of constitutive alkali-labile sites (ALS) has been investigated using a protocol of DNA breakage detection-fluorescence in situ hybridization and comet assay in spermatozoa of donkey (Equus asinus) and stallion (Equus caballus). These results were compared with those obtained using a similar experimental approach using somatic cells. The relative abundance of ALS was of the order of four times more in spermatozoa than in somatic cells. Alkali-labile sites showed a tendency to cluster localized at the equatorial-distal regions of the sperm. The amount of hybridized signal in the ALS in the sperm of donkey (Equus asinus) was 1.3 times greater than in stallion (Equus caballus), and the length of the comet tail obtained in donkey sperm was 1.6 times longer than that observed in stallion (P < 0.05); however, these differences were not appreciated in somatic cells. In conclusion, ALS localization in sperm is not a randomized event and a different pattern of ALS distribution occurs for each species. These results suggest that ALS represents a species-specific issue related to chromatin organization in sperm and somatic cells in mammalian species, and they might diverge even with very short phylogenetic distances.

The effect of two pre-cryopreservation single layer colloidal centrifugation protocols in combination with different freezing extenders on the fragmentation dynamics of thawed equine sperm DNA

Background

Variability among stallions in terms of semen cryopreservation quality renders it difficult to arrive at a standardized cryopreservation method. Different extenders and processing techniques (such us colloidal centrifugation) are used in order to optimize post-thaw sperm quality. Sperm chromatin integrity analysis is an effective tool for assessing such quality. The aim of the present study was to compare the effect of two single layer colloidal centrifugation protocols (prior to cryopreservation) in combination with three commercial freezing extenders on the post-thaw chromatin integrity of equine sperm samples at different post-thaw incubation (37°C) times (i.e., their DNA fragmentation dynamics).

Results

Post-thaw DNA fragmentation levels in semen samples subjected to either of the colloidal centrifugation protocols were significantly lower (p<0.05) immediately after thawing and after 4 h of incubation at 37°C compared to samples that underwent standard (control) centrifugation. The use of InraFreeze® extender was associated with significantly less DNA fragmentation than the use of Botu-Crio® extender at 6 h of incubation, and than the use of either Botu-Crio® or Gent® extender at 24 h of incubation (p<0.05).

Conclusions

These results suggest that single layer colloidal centrifugation performed with extended or raw semen prior to cryopreservation reduces DNA fragmentation during the first four hours after thawing. Further studies are needed to determine the influence of freezing extenders on equine sperm DNA fragmentation dynamics.

Dabigatran for stroke prevention in nonvalvular atrial fibrillation: answers to challenging "real-world" questions

Dabigatran etexilate is a novel, oral, reversible, direct thrombin inhibitor that constitutes a major breakthrough for stroke prevention in patients with nonvalvular atrial fibrillation (AF). Dabigatran was the first new oral anticoagulant approved in Europe and became available in Portugal, for stroke prevention in nonvalvular AF, earlier than in most European countries. This paper is the joint effort of a panel of experts from different specialties and provides information on the use of dabigatran, in anticipation of the challenges that will come with increased usage.

Shared Y chromosome repetitive DNA sequences in stallion and donkey as visualized using whole-genomic comparative hybridization

The genome of stallion (Spanish breed) and donkey (Spanish endemic Zamorano-Leonés) were compared using whole comparative genomic in situ hybridization (W-CGH) technique, with special reference to the variability observed in the Y chromosome. Results show that these diverging genomes still share some highly repetitive DNA families localized in pericentromeric regions and, in the particular case of the Y chromosome, a sub-family of highly repeated DNA sequences, greatly expanded in the donkey genome, accounts for a large part of the chromatin in the stallion Y chromosome.

Heritable factors shape natural human IgM reactivity to Ro60/SS-A and may predispose for SLE-associated IgG anti-Ro and anti-La autoantibody production

Systemic lupus erythematosus (SLE) is characterized by various IgG autoreactivities, among which anti-Ro/SS-A is particularly pathology-associated and early detectable. SLE also shows significant familial aggregation, but genetic factors are not well understood and remain controversial for disease-associated IgG. Here we report that IgM anti-Ro showed a uniquely high degree of heritability in a study of SLE-affected families. Unlike IgM anti-La or anti-dsDNA, IgM anti-Ro was also significantly correlated to IgG anti-Ro among SLE patients, as well as to IgG anti-La and anti-dsDNA. We conclude that largely genetically determined, thus natural IgM anti-Ro-bearing precursor B-cells, may be an important factor for class switching and determinant spreading in early phases of SLE pathogenesis. Furthermore, we found unexpected sex differences in isotype/specificity correlations among SLE-unaffected relatives and control subjects, which could help understand the strong gender bias associated with SLE. We propose that the study of such correlation structures may reveal characteristic spreading pathways relevant for human SLE.

[Monitoring therapy with oral anticoagulants. Anticoagulation clinics vs assistant physician]

Most patients on chronic oral anticoagulant therapy are monitored through anticoagulation clinics, or rather by assistant physicians. Our aim was to compare warfarin anticoagulated patients who were treated with usual medical care (assistant physician) with those treated routinely at an anticoagulation clinic for anticoagulation control. The later was assessed by comparing in both groups of patients the proportion of INRs within the therapeutic range, above 5.0 and below 1.5. The group treated at an anticoagulation clinic achieved better anticoagulation control (both among the patients receiving lower-range anticoagulation therapy and in the patients requiring higher-range anticoagulation therapy) than the group treated with usual medical care.

Evidence for CTLA4 as a susceptibility gene for systemic lupus erythematosus

Several lines of evidence implicate the Cytotoxic T Lymphocyte Antigen 4 (CTLA4) gene in susceptibility to autoimmune disease. We have examined the association of systemic lupus erythematosus (SLE) with polymorhisms within the CTLA4 gene that were previously proposed to regulate CTLA-4 function: a single nucleotide polymorphism (SNP) in position +49 of exon 1 and a dinucleotide repeat in the 3' untranslated region (3'UTR). The 3'UTR repeat showed a significant association with SLE, with one allele conferring susceptibility and another conferring protection to the disease. The associated alleles do not support previous suggestions of an allele size-dependent effect of the 3' UTR polymorphism in autoimmunity development and instead suggest that it is in linkage disequilibrium with a true causative locus. No association of the exon 1 SNP with SLE was found in our population. Given the conflicting results obtained in different studies on the association of SLE with this polymorphism, we performed a meta-analysis including seven previously published studies and the present one. Significantly increased and decreased risks for SLE were found for carriers of the G allele and the A allele, respectively. The functional characterization of disease-associated CTLA4 gene variants is now required to elucidate their role in the pathogenesis of SLE and other autoimmune diseases.

Molecular basis of inherited antithrombin deficiency in Portuguese families: identification of genetic alterations and screening for additional thrombotic risk factors

Antithrombin (AT), the most important coagulation serine proteases inhibitor, plays an important role in maintaining the hemostatic balance. Inherited AT deficiency, mainly characterized by predisposition to recurrent venous thromboembolism, is transmitted in an autosomal dominant manner. In this study, we analyzed the underlying genetic alterations in 12 unrelated Portuguese thrombophilic families with AT deficiency. At the same time, the modulating effect of the FV Leiden mutation, PT 20210A, PAI-1 4G, and MTHFR 677T allelic variants, on the thrombotic risk of AT deficient patients was also evaluated. Three novel frameshift alterations, a 4-bp deletion in exon 4 and two 1-bp insertions in exon 6, were identified in six unrelated type I AT deficient families. A novel missense mutation in exon 3a, which changes the highly conserved F147 residue, and a novel splice site mutation in the invariant acceptor AG dinucleotide of intron 2 were also identified in unrelated type I AT deficient families. In addition to these, two previously reported missense mutations changing the AT reactive site bond (R393-S394) and leading to type II-RS deficiency, and a previously reported cryptic splice site mutation (IVS4-14G-->A), were also identified. In these families, increased thrombotic risk associated with co-inheritance of the FV Leiden mutation and of the PAI-1 4G variant was also observed. In conclusion, we present the first data regarding the underlying genetic alterations in Portuguese thrombophilic families with AT deficiency, and confirm that the FV Leiden mutation and probably the PAI-1 4G variant represent additional thrombotic risk factors in these families.

Rheumatic manifestations of infective endocarditis in non-addicts. A 12-year study

Infective endocarditis (IE) is due to a microbial infection of the heart valves or of the endocardium in close proximity to either congenital or acquired cardiac defects. This infection is associated with a high risk of complications. Rheumatic manifestations are known to be frequent complications of IE. Controversy, however, frequently exists about the actual incidence of these complications. This may be due to the small number of series describing the frequency and type of rheumatic manifestations, the absence of uniform criteria used for the diagnosis of IE, and the fact that some studies on rheumatic manifestations in IE have been described from tertiary referral centers, which implicates associated problems of referral bias and uncertainty of denominator population. To investigate further the incidence, clinical spectrum, and outcome of patients with IE and rheumatic manifestations, we examined the features of patients diagnosed with clinically definite IE according to the Duke classification criteria at the single reference hospital for a defined population in northwestern Spain during a 12-year period. Between 1987 and 1998, 100 consecutive patients had 110 episodes of clinically definite IE. Rheumatic manifestations were observed in 46 of the 110 episodes (41.8%). As in other western countries, they occurred more commonly in men aged in their 50s. The most frequent valve involved was the aortic (43.5%) followed by the mitral valve (30.4%). Myalgia was a frequent symptom. Peripheral arthritis, generally as monoarthritis, was clinically evident in 15 cases (13.6%), and sacroiliitis in 1 patient. Low back pain was described in 14 cases (12.7%). Septic discitis was observed in 2 cases, and biopsy-proved cutaneous leukocytoclastic vasculitis was found in 4 cases. Other conditions such as trochanteric bursitis and polymyalgia were observed in 2 and 1 case, respectively. Apart from a significantly higher frequency of hematuria and a trend to lower serum complement levels in patients with rheumatic complications, no differences in clinical features, laboratory tests, or microbiologic blood culture results were found between cases with IE with or without rheumatic manifestations. Also, although patients with rheumatic manifestations had more embolic complications, the inhospital mortality rate in patients with rheumatic manifestations was not significantly different from that of the rest of the patients. The present study supports the claim that rheumatic complications are frequent in patients with clinically definite IE from southern Europe. The presence of musculoskeletal or vasculitic manifestations may be of some help, as warning signs, for the recognition of patients with severe disease who require rapid diagnosis and therapy.

Improved safety through tamoxifen-regulated induction of cytotoxic genes delivered by Ad vectors for cancer gene therapy

The transfer of pro-apoptotic genes to tumors is one of the most promising strategies for anticancer gene therapy. However, the use of potentially toxic genes, such as tumor suppressor genes or apoptotic genes, needs controllable transgene activation. To achieve regulation of the transgene at a desired time, we developed an adenovirus (Ad) vector, in which the apoptotic activity of the target gene has been made 4-OHT-dependent by fusion to the ligand binding-domain of the estrogen receptor (ER). For evaluation of the system in human tumor cells, we used the E2F1 gene which encodes a transcription factor that triggers massive apoptosis in several human cancers. AdER-E2F1 expressed high levels of transgene over at least 1 week. Upon activation of E2F1 by the ligand 4-hydroxy-tamoxifen (4-OHT) the ER-E2F1 fusion protein correctly translocated from the cytosol to the nucleus, transactivated E2F-dependent promoters, and rapidly induced substantial E2F1-related toxicity. Finally, experiments in nude mice showed tightly regulated tumor growth suppression in vivo. Taken together, our system represents a powerful approach for tight regulation and rapid induction of cytotoxicity as the major criteria for safe gene delivery.

[Total arterial myocardial revascularization with both mammary arteries without extracorporeal circulation]

INTRODUCTION

Tector has described the off-pump total arterial revascularization technique, using multiple anastomosis with both internal thoracic arteries. To reduce surgical morbid-mortality, we have proposed the use of this technique without extracorporeal circulation.

PATIENTS AND METHODS

From April, 1998 the off-pump <<Tector>> technique was performed in 92 patients, 74 male (80%) and 18 female (20%), with a mean age of 64.9+/-8.1 years (42-78). Preoperative angiography demonstrated triple-vessel disease in 58 (63%) patients, and left main disease was present in 19 (20.5%) patients. Forty patients (43.5%) showed unstable angina, 24 patients (26%) significant peripheral vascular disease, and 26 (28%) diabetes mellitus. Both internal thoracic arteries were harvested using the skeletonization technique and were used like a <<T or T>> graft. The flow in the graft was measured using a flowmeter, and in 24 (26%) patients by angiographic study.

RESULTS

A total of 274 distal anastomoses were performed, 122 (44.6%) in the lateral or inferior wall, and 69 (25.2%) were sequential, with an average of 2.98 bypass/patient. In 59.8% of the patients a triple bypass was performed, 22% double bypass, 17% cuadruple bypass and 1 patient a quintuple bypass. During the initial six hours 64.9% of patients were extubated. Only one patient (1.1%) needed intraaortic ballon pumping and 3 (3.2%) inotropics during the postoperative course. Hospital mortality was 3 (3.2%) patients. Reoperation for bleeding was needed in just one patient (1.1%), and 78.3% of patients were not transfused. Mediastinitis occurred in 3 patients (3.2%). Postoperative stroke was not observed. At 7.7+/-2.8 months of mean follow-up all patients were free of symptoms and the global patency rate of 94%.

CONCLUSIONS

Off-pump Tector technique appears to be safe, offering a complete arterial revascularization and showing a reduction of surgical morbidity.

[Treatment of idiopathic facial paralysis: corticoids versus acyclovir versus empirical treatment]

Bell's palsy has no specific treatment because its cause is still debated. The most widely accepted theory postulates an immunovirological origin consisting of the reactivation of a silent herpesvirus on the geniculate ganglion. We studied three groups of patients with Bell's palsy who received different treatments in an attempt to discern differences in evolution between treatment groups.