Review: The role of male reproductive tract secretions in ruminant fertility.

Male fertility largely depends on the ability to produce sperm that can transmit the paternal information onto the next generation. However, the factors that are critical for sperm function and the subsequent development of healthy offspring are still not completely understood in ruminants. Importantly, sperm function is not completely encoded by germ cell DNA, but rather, depends on sequential acquisition, loss, and modification of elements through interaction with secretions from the testes, epididymides, and accessory glands (collectively termed seminal plasma). In addition, these secretions can play a role in the inheritance of paternal environmental effects by progeny. This is likely achieved directly, by the regulation of sperm epigenetic effectors, and indirectly, by altering the female environment in which the individual develops. This review will provide an overview of the different organs that contribute to seminal plasma in ruminants, and summarise how their secretions shape sperm function and modulate the female reproductive tract. Finally, some consideration will be given to the potential of paternal factors to affect embryo development and offspring health in ruminants.

First detection of SARS-CoV-2 variant B.1.1.529 (Omicron) in Ecuador.

The National Institute of Research and Public Health reported the first local record of the Omicron variant detected in Ecuador. A fully vaccinated subject returned from South Africa with a negative RT-PCR. We present the cumulative frequency of the variants in Ecuador and a phylogenetic analysis of this new Omicron.

Removal of sialic acid from bull sperm decreases motility and mucus penetration ability but increases zona pellucida binding and polyspermic penetration in vitro.

This study tested the hypothesis that sperm sialic acid (Sia) is required to reach the site of fertilization, and that successful fertilization requires recognition of Sia from both the sperm and oocyte to occur. In addition, it has recently been reported that Siglecs (Sia-binding-immunoglobulin-like lectins) are present on the sperm surface. Thus, the possibility that the recognition of oocyte Sia was sperm-Siglec-mediated was also addressed. Sperm exposed to neuraminidase (NMase) exhibited lower overall and progressive motility, which translated to a decreased ability to swim through cervical mucus from cows in oestrus. In addition, when either sperm or cumulus-oocyte complexes (COCs) were treated with NMase, a decrease in cleavage and blastocyst rate was observed. However, incubation of sperm with increasing concentrations of anti-Siglec-2, -5, -6 and -10 antibodies prior to fertilization had no effect on their fertilizing ability. Interestingly, treatment with NMase increased the number of sperm bound to the ZP but also the rate of polyspermic fertilization. Flow cytometry analysis revealed no differences in the percentage of capacitated or acrosome-reacted sperm. These results suggest that Sia are required to reach the site of fertilization but need to be removed for sperm-oocyte interaction. However, fine regulation is needed to avoid abnormal fertilization which can lead to impaired embryo development.

Siglec expression on the surface of human, bull and ram sperm.

Sialic acid (Sia) is a major constituent of both the sperm glycocalyx and female reproductive mucosal surface and is involved in regulating sperm migration, uterotubal reservoir formation and oocyte binding. Siglecs (sialic acid-binding immunoglobulin - like lectins) commonly found on immune cells, bind to Sia in a linkage- and sugar-specific manner and often mediate cell-to-cell interactions and signalling. Proteomic and transcriptomic analysis of human and bovine sperm have listed Siglecs, but to date, their presence and/or localisation on sperm has not been studied. Therefore, the aim of this study was to characterise the presence of Siglecs on the surface of bovine, human and ovine sperm using both immunostaining and Western blotting. Siglec 1, 2, 5, 6, 10 and 14 were identified and displayed both species- and regional-specific expression on sperm. Almost universal expression across Siglecs and species was evident in the sperm neck and midpiece region while variable expression among Siglecs, similar among species, was detected in the head and tail regions of the sperm. The possible role for these proteins on sperm is discussed.

Effect of seminal plasma from high- and low-fertility bulls on cauda epididymal sperm function.

The aim of this study was to characterise the effect of seminal plasma (SP) from bulls of high or low fertility on sperm function. First, the effect of SP on the motility of fresh cauda epididymal spermatozoa (CES) and frozen-thawed ejaculated spermatozoa was assessed (Experiment 1a). Seminal plasma was then collected from bulls of known high and low fertility. Pooled CES were incubated in the SP from each bull, diluted and assessed for motility and viability on Days 1, 2, 3 and 5 after packaging as fresh semen (Experiment 1b). Also assessed were motility, kinematics, viability and mitochondrial membrane potential after thawing (Experiment 1c) as well as hypotonic resistance (Experiment 2) and fertilisation potential using in vitro fertilisation (Experiment 3). Seminal plasma increased the motility of CES (P<0.05); however, there was no effect of SP on the motility and viability of fresh CES or on CES post-thaw motility, viability and mitochondrial membrane potential (P>0.05). The hypotonic resistance of CES was reduced by SP (P<0.05), irrespective of whether the SP was from high- or low-fertility bulls. Seminal plasma from high- or low-fertility bulls had no effect on cleavage or blastocyst rates (P>0.05). In conclusion, SP affects the physiological function of CES but there is no difference between SP from high- or low-fertility bulls.

Profiling bovine blastocyst microRNAs using deep sequencing.

MicroRNAs (miRNAs) are known to control several reproductive functions, including oocyte maturation, implantation and early embryonic development. Recent advances in deep sequencing have allowed the analysis of all miRNAs of a sample. However, when working with embryos, due to the low RNA content, miRNA profiling is challenging because of the relatively large amount of total RNA required for library preparation protocols. In the present study we compared three different procedures for RNA extraction and prepared libraries using pools of 30 bovine blastocysts. In total, 14 of the 15 most abundantly expressed miRNAs were common to all three procedures. Furthermore, using miRDeep discovery and annotation software (Max Delbrück Center), we identified 1363 miRNA sequences, of which bta-miR-10b and bta-miR-378 were the most abundant. Most of the 179 genes identified as experimentally validated (86.6%) or predicted targets (13.4%) were associated with cancer canonical pathways. We conclude that reliable analysis of bovine blastocyst miRNAs can be achieved using the procedures described herein. The repeatability of the results across different procedures and independent replicates, as well as their consistency with results obtained in other species, support the biological relevance of these miRNAs and of the gene pathways they modulate in early embryogenesis.

Relationship between in vitro sperm functional assessments, seminal plasma composition, and field fertility after AI with either non-sorted or sex-sorted bull semen.

The hypothesis of this study was that different in vitro parameters are required to predict the in vivo fertility of non-sorted (NS) and sex-sorted (SS) semen. Thus, the aim was to correlate in vitro bull sperm functional parameters (experiment 1) and seminal plasma composition (experiment 2) with pregnancy rates using 2 cohorts of bulls (NS and SS). Experiment 1: ejaculates from each bull (n = 3 ejaculates per bull; n = 6 bulls for both NS and SS) were assessed for motility, thermal stress tolerance and morphology using microscopy, and viability, osmotic resistance, mitochondrial membrane potential, and acrosome integrity using flow cytometry. Fertilizing ability was assessed using IVF. Experiment 2: ejaculates (n = 3 per bull; n = 8 and 6 bulls for NS and SS, respectively) were collected, seminal plasma harvested and frozen and later analyzed for amino acid and fatty acid composition using gas chromatography mass spectrometry. In the NS cohort of bulls, there was no correlation between pregnancy rate and any of the sperm functional parameters assessed. However, within the SS cohort, motility and viability were correlated with pregnancy rate (r = 0.84 and 0.80, respectively; P < 0.05). There was no correlation between IVF outcome and pregnancy rate in either the SS or NS cohort of bulls. In the NS cohort of bulls, concentrations of the amino acid isoleucine and the fatty acid tricosylic acid (C23:0) were correlated with pregnancy rate (r = 0.80 and 0.74, respectively; P < 0.05). Within the SS cohort of bulls, the amino acid glutamic acid and the fatty acid arachidic acid (C20:0) were correlated with pregnancy rate (r = 0.84 and 0.82, respectively; P < 0.05). In conclusion, this study suggests that different in vitro markers of fertility are required to predict the fertility of NS and SS sperm.

Fractura bilateral de tibia en el Hospital Universitario del Valle: serie de casos / Management of bilateral tibial fractures: case series

Introducción: la fractura bilateral de tibia es el producto de traumatismos de alta energía, los cuales ocasionan en su mayoría múltiples lesiones asociadas, como lesión vascular, nerviosa y amputación de las extremidades. El objetivo de este estudio fue determinar los resultados del tratamiento de la fractura bilateral de tibia. Materiales y métodos: se diseñó un estudio observacional descriptivo tipo serie de casos. Se incluyeron pacientes mayores de 18 años de edad, con fractura bilateral de tibia, que fueron manejados en el Hospital Universitario del Valle de la ciudad de Cali, entre julio del 2004 y julio del 2006, con un periodo de seguimiento mínimo de 3 meses posterior al trauma. Se tuvieron en cuenta datos sociodemográficos, datos relacionados con el trauma, lesiones asociadas, clasificación de las fracturas, procedimientos y complicaciones. Resultados: en un periodo de dos años, se incluyeron 24 pacientes, de los cuales 17 (71%) eran hombres y 7 (29%) eran mujeres. El promedio de edad fue de 40 años y el mecanismo de trauma más frecuente fue accidente de tránsito (87,5%), siendo el auto contra peatón el más común. Se encontraron 26 fracturas cerradas y 22 expuestas. Las fracturas más frecuentes según la clasificación AO fueron las 42A3. La clasificación más frecuente de Tscherne para fracturas abiertas fue grado II y para las cerradas fue 0. El puntaje promedio de MESS estuvo entre 4,8 y 5,3. El 87,5% de los pacientes ingresó el primer día del trauma y la primera cirugía se realizó en promedio en el segundo día, la mayoría con lavado, desbridamiento, curetaje y tutor externo. Otros tratamientos fueron reducción cerrada, osteosíntesis con placa, clavos bloqueados, colgajos e injertos de piel y óseos. Las complicaciones más frecuentes fueron la infección, la amputación y el daño vascular. Discusión: en este estudio, se encontró una mayor puntuación en la clasificación de Tscherne y en la escala de MESS, en aquellos que terminaron con amputación de una de sus extremidades inferiores, comparados con los no amputados.

High incidence of severe infections in heart transplant recipients receiving tacrolimus.

BACKGROUND: Tacrolimus (FK) is being increasingly used as an alternative to cyclosporine (CyA) in heart transplantation (HTx). It is believed to engender slightly more powerful protection against acute rejection. However, the increased immunosuppression could result in an excess of infectious complications. METHODS: Our study compared the incidence of major infections (MInf), defined as life-threatening infectious episodes requiring admission and intravenous (IV) antimicrobial therapy, among a series of HTx recipients treated with either FK (n=30) or CyA (n=84). RESULTS: A total of 21 patients received FK in an elective protocol and 9 patients initially treated with CyA were converted to FK. Tacrolimus was combined with azathioprine and prednisone in 21 cases, and with mycophenolate mofetil and steroids in 8 recipients. After a follow-up between 6 and 37 months, 11 patients (37%) in the FK group developed 13 episodes of MInf, most (85%) occurring during the first posttransplant year. Conversely, CyA patients (n=84), a group with similar characteristics and follow-up, showed a MInf incidence of 12% (P<.05). Among the FK group, the most common site of MInf was pulmonary (69%). A variety of opportunistic agents caused MInf in 54% of cases, whereas the remaining ones were attributed to nosocomial bacteria. There were three deaths (27% of all MInf), all in azathioprine-treated patients with initial FK therapy. CONCLUSIONS: Tacrolimus therapy seems to be associated with an increased incidence of severe infections in HTx recipients. We recommend aggressive diagnostic and therapeutic approaches for patients on FK who develop signs or symptoms of infection in the first year after HTx.

Pulmonary nocardiosis in heart transplant recipients: treatment and outcome.

BACKGROUND: Nocardial infections typically affect patients receiving immunosuppressants, occurring early after surgery in 3% to 40% of heart transplant (HTx) recipients. The emergence of antibiotic resistance and occurrence of disease recurrences in AIDS population has engendered controversy about the treatment for immunodepressed HTx patients. METHODS: We present a retrospective study of the diagnosis, treatment and outcome of 560 HTx recipients between 1984 and 2002. RESULTS: Among the five cases of Nocardia infection (0.9%), three cases developed late after HTx (between 3.1 and 11 years follow-up). All patients had pulmonary disease and one in addition had subcutaneous nodules. Microbiological diagnosis required open lung biopsy in one case. All patients were treated primarily with trimethoprim-sulphamethoxazole, but evidence of resistance to sulfonamides led us to change the antimicrobial combination in two cases. Four patients who received one year of antibiogram-guided therapy showed complete healing without recidivism. Three patients died, all due to non-related causes, at follow-ups between 1 and 5 years. In one case a cutaneous recurrence of disease was attributed to noncompliance. CONCLUSIONS: Nocardiosis in current HTx is less common than previously reported. Its incidence seems to be delayed in time with modern immunosuppressants. Given the high incidence of sulfamide resistance, treatment must be guided by antibiotic sensitivity. We believe that maintenance therapy for a whole year is the appropriate option in order to avoid recidivism in this population.

Current induction immunosuppression and post-heart transplant lymphoproliferative disorders.

BACKGROUND: The use of high-dose OKT3 has been reported to be associated with a high incidence of posttransplant lymphoproliferative disorders (PTLD) in heart transplantation (HTx) recipients. The incidence and characteristics of PTLD with current induction protocols remain largely unknown. The aim of our study was to analyze the incidence and characteristics of PTLD in a large series of HTx recipients treated with low-dose OKT3 induction. METHODS: From 1984 to 2002, a retrospective review of diagnosis, treatment, and evolution of PTLD cases was performed on the 560 patients who underwent HTx in our center. RESULTS: The incidence of PTLD was 1% (6/560). The disease occurred early after HTx in two cases and between 13 and 121 months in the other four. Molecular studies showed evidence of Epstein-Barr virus (EBV) infection in four patients. B-cell proliferation was observed in five cases, and T-cell proliferation in the other one. Various therapies were employed for each patient. Ganciclovir and reduction in immunosuppression were the most common measures. Interestingly, OKT3 was used as a specific anti-T-cell proliferation agent with some success in the one case of T-cell PTLD. Complete remission was achieved in just two patients, whereas the other four (67%) died, mostly due to other conditions. CONCLUSIONS: The use of low-dose OKT3 as induction therapy did not increase the incidence of PTLD in our series. Late appearance of disease prevailed among our patients. Despite a multidisciplinary approach to therapy, including the use of OKT3 against T-cell proliferation, the mortality rate was high (67%).