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In Brazil, around 80% of snakebites are caused by snakes of the genus Bothrops. A three-dimensional culture model was standardized and used to perform treatments with Bothrops erythromelas venom (BeV) and its antivenom (AV). The MRC-5 and L929 cell lines were cultured at increasing cell densities. Morphometric parameters were evaluated through images obtained from an inverted microscope: solidity, circularity, and Feret diameter. L929 microtissues (MT) showed better morphometric data, and thus they were used for further analysis. MT viability was assessed using the acridine orange and ethidium bromide staining method, which showed viable cells in the MT on days 5, 7, and 10 of cultivation. Histochemical and histological analyses were performed, including hematoxylin/eosin staining, which showed a good structure of the spheroids. Alcian blue staining revealed the presence of acid proteoglycans. Immunohistochemical analysis with ki-67 showed different patterns of cell proliferation. The MT were also subjected to pharmacological tests using the BeV, in the presence or absence of its AV. The results showed that the venom was not cytotoxic, but it caused morphological changes. The MT showed cell detachment, losing their structure. The antivenom was able to partially prevent the venom activities.

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Assisted reproduction is a key aspect of modern animal breeding, providing valuable assistance in improving breeding programs. In this field, the administration of exogenous hormones, such as follicle-stimulating hormone (FSH), plays a crucial role in the induction of multiple ovulations. However, commercial FSH used in veterinary practice has been derived primarily from pituitary glands, obtained mostly from pigs for nearly four decades. Although these hormones have contributed significantly to the advancement of assisted reproductive techniques, they have certain limitations that warrant further improvements. These limitations include contamination with luteinizing hormone (LH), the potential risk of pathogen contamination, the potential to trigger an immune response in non-pig species, and the short half-life in circulation, requiring the implementation of complex 8-dose superovulation schedules. Our research team has developed and characterized a new variant of bovine follicle-stimulating hormone (bscrFSH) to address these limitations. The new hormone is produced recombinantly in CHO cell cultures, with a specific productivity of about 30 pg/cell/day. The bscrFSH can be purified to a high purity of 97 % using a single step of immobilized metal affinity chromatography (IMAC). N-glycan analysis of bscrFSH showed that approximately 74 % of the glycans corresponded to charged structures, including mono-, di-, tri-, and tetra-sialylated glycans. Superovulation trials conducted in cattle revealed that bscrFSH, administered at a total dose of about 0.5 µg per kg of body weight, using a decrescent schedule of 4 doses with 24-h intervals, resulted in an average yield of 8-12 transferable embryos per animal. Further research is required; however, the preliminary findings indicate that bscrFSH, currently packaged under the provisional brand name of Cebitropin B, holds potential as a commercial product for assisted reproduction in ruminants.

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Biopolymers are biodegradable and renewable and can significantly reduce environmental impacts. For this reason, biocomposites based on a plasticized starch and cross-linker matrix and with a microfibrillated OCC cardboard cellulose reinforcement were developed. Biocomposites were prepared by suspension casting with varied amounts of microfibrillated cellulose: 0, 4, 8, and 12 wt%. Polyethylene glycol diglycidyl ether (PEGDE) was used as a cross-linking, water-soluble, and non-toxic agent. Microfibrillated cellulose (MFC) from OCC cardboard showed appropriate properties and potential for good performance as a reinforcement. In general, microfiber incorporation and matrix cross-linking increased crystallization, reduced water adsorption, and improved the physical and tensile properties of the plasticized starch. Biocomposites cross-linked with PEGDE and reinforced with 12 wt% MFC showed the best properties. The chemical and structural changes induced by the cross-linking of starch chains and MFC reinforcement were confirmed by FTIR, NMR, and XRD. Biodegradation higher than 80% was achieved for most biocomposites in 15 days of laboratory compost.

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Microbialites are organosedimentary structures formed mainly due to the precipitation of carbonate minerals, although they can also incorporate siliceous, phosphate, ferric, and sulfate minerals. The minerals' precipitation occurs because of local chemical changes triggered by changes in pH and redox transformations catalyzed by the microbial energy metabolisms. Here, geochemistry, metagenomics, and bioinformatics tools reveal the key energy metabolisms of microbial mats, stromatolites and an endoevaporite distributed across four hypersaline lagoons from the Salar de Atacama. Chemoautotrophic and chemoheterotrophic microorganisms seem to coexist and influence microbialite formation. The microbialite types of each lagoon host unique microbial communities and metabolisms that influence their geochemistry. Among them, photosynthetic, carbon- and nitrogen- fixing and sulfate-reducing microorganisms appear to control the main biogeochemical cycles. Genes associated with non-conventional energy pathways identified in MAGs, such as hydrogen production/consumption, arsenic oxidation/reduction, manganese oxidation and selenium reduction, also contribute to support life in microbialites. The presence of genes encoding for enzymes associated with ureolytic processes in the Cyanobacteria phylum and Gammaproteobacteria class might induce carbonate precipitation in hypersaline environments, contributing to the microbialites formation. To the best of our knowledge, this is the first study characterizing metagenomically microbialites enriched in manganese and identifying metabolic pathways associated with manganese oxidation, selenium reduction, and ureolysis in this ecosystem, which suggests that the geochemistry and bioavailability of energy sources (As, Mn and Se) shapes the microbial metabolisms in the microbialites.

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NK-lysin is a potent antimicrobial peptide (AMP) with antimicrobial activity against bacteria, fungi, viruses, and parasites. NK-lysin is a type of granulysin, a member of the saposin-like proteins family first isolated from a pig's small intestine. In previous work, for the first time, we identified four variants of nk-lysin from Atlantic salmon (Salmo salar) using EST sequences. In the present study, we reported and characterized two additional transcripts of NK-lysin from S. salar. Besides, we evaluated the tissue distribution of three NK-lysins from S. salar and assessed the antimicrobial, hemolytic, and immunomodulatory activities and signaling pathways of three NK-lysin-derived peptides. The synthetic peptides displayed antimicrobial activity against Piscirickettsia salmonis (LF-89) and Flavobacterium psychrophilum. These peptides induced the expression of immune genes related to innate and adaptive immune responses in vitro and in vivo. The immunomodulatory activity of the peptides involves the mitogen-activated protein kinases-mediated signaling pathway, including p38, extracellular signal-regulated kinase 1/2, and/or c-Jun N-terminal kinases. Besides, the peptides modulated the immune response induced by pathogen-associated molecular patterns (PAMPs). Our findings show that NK-lysin could be a highly effective immunostimulant or vaccine adjuvant for use in fish aquaculture.

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Introduction: The emergence of multi-drug-resistant bacteria is one of the main concerns in the health sector worldwide. The conventional strategies for treatment and prophylaxis against microbial infections include the use of antibiotics. However, these drugs are failing due to the increasing antimicrobial resistance. The unavailability of effective antibiotics highlights the need to discover effective alternatives to combat bacterial infections. One option is the use of metallic nanoparticles, which are toxic to some microorganisms due to their nanometric size. Methods: In this study we (1) synthesize and characterize bismuth and silver nanoparticles, (2) evaluate the antibacterial activity of NPs against Staphylococcus aureus and Escherichia coli in several infection models (in vivo models: infected wound and sepsis and in vitro model: mastitis), and we (3) determine the cytotoxic effect on several cell lines representative of the skin tissue. Results and discussion: We obtained bimetallic nanoparticles of bismuth and silver in a stable aqueous solution from a single reaction by chemical synthesis. These nanoparticles show antibacterial activity on S. aureus and E. coli in vitro without cytotoxic effects on fibroblast, endothelial vascular, and mammary epithelium cell lines. In an infected-wound mice model, antibacterial effect was observed, without effect on in vitro mastitis and sepsis models.

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BACKGROUND: Skin cancer is one of the most frequent types of cancer, and cutaneous squamous cell carcinoma (cSCC) constitutes 20% of non-melanoma skin cancer (NMSC) cases. PTCH1, a tumor suppressor gene involved in the Sonic hedgehog signaling pathway, plays a crucial role in neoplastic processes. METHODS: An analytical cross-sectional study, encompassing 211 cSCC patients and 290 individuals in a control group (CG), was performed. A subgroup of samples was considered for the relative expression analysis, and the results were obtained using quantitative real-time PCR (qPCR) with TaqMan® probes. The functional, splicing, and disease-causing effects of the proposed variants were explored via bioinformatics. RESULTS: cSCC was predominant in men, especially in sun-exposed areas such as the head and neck. No statistically significant differences were found regarding the rs357564, rs2236405, rs2297086, and rs41313327 variants of PTCH1, or in the risk of cSCC, nor in the mRNA expression between the cSCC group and CG. A functional effect of rs357564 and a disease-causing relation to rs41313327 was identified. CONCLUSION: The proposed variants were not associated with cSCC risk in this Mexican population, but we recognize the need for analyzing larger population groups to elucidate the disease-causing role of rare variants.

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As part of a long-term study aiming to isolate and identify yeast species that inhabit the surface of leaves and fruits of native fine-aroma cacao in the department of Amazonas, Peru, we obtained multiple isolates of Hannaella species. Yeasts of the genus Hannaella are common inhabitants of the phyllosphere of natural and crop plants. On the basis of morphological, and physiological characteristics, and sequence analysis of the D1/D2 domains of the large subunit rRNA gene (LSU) and the internal transcribed spacer region (ITS), we identified five species of Hannaella from the phyllosphere of Peruvian cacao. Four have been previously described: H. phyllophila (isolates KLG-073, KLG-091), H. pagnoccae (KLG-076), H. sinensis (KLG-121), and H. taiwanensis (KLG-021). A fifth, represented by eight isolates (KLG-034, KLG-063, KLG-074, KLG-078, KLG-79, KLG-082, KLG-084, KLG-085), is not conspecific with any previously described Hannaella species, and forms the sister clade to H. surugaensis in the phylogenetic analysis. It has 2.6-3.9% (18-27 substitutions, 2-4 deletions, and 1-3 insertions in 610-938 bp-long alignments), and 9.8-10.0% nucleotide differences (37 substitutions and 14 insertions in 511-520 bp-long alignments) in the LSU and ITS regions, respectively, to H. surugaensis type strain, CBS 9426. Herein, the new species Hannaella theobromatis sp. nov. is described and characterised. The species epithet refers to its epiphytic ecology on its host Theobroma cacao.

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BACKGROUND: Basal cell carcinoma (BCC) represents about 80% of all cases of skin cancer. The PTCH1 is a transmembrane protein of the Sonic Hedgehog signaling pathway that regulates cell proliferation. Genetic variants in PTCH1 gene have been previously described in association with BCC development. In addition, PTCH1 mRNA and protein expression analysis are also significant to understand its role in skin cancer physiopathology. METHODS: An analytical cross-sectional study was performed, and a total of 250 BCC patients and 290 subjects from the control group (CG) were included, all born in western Mexico. The genotypes and relative expression of the mRNA were determined by TaqMan® assay. The protein expression was investigated in 70 BCC paraffin-embedded samples with PTCH1 antibodies. Semi-quantitative analysis was performed to determine the expression level in the immunostained cells. RESULTS: We did not find evidence of an association between PTCH1 rs357564, rs2297086, rs2236405, and rs41313327 genetic variants and susceptibility to BCC. Likewise, no statistically significant differences were found in the comparison of the mRNA level expression between BCC and CG (p > 0.05). The PTCH1 protein showed a low expression in 6 of the analyzed samples and moderate expression in 1 sample. No association was found between genetic variants, protein expression, and demographic-clinical characteristics (p > 0.05). CONCLUSION: The studied PTCH1 variants may not be associated with BCC development in the Western Mexico population. The PTCH1 mRNA levels were lower in patients with BCC compared to the control group, but its protein was underexpressed in the tissue samples.

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Toll-like receptor 5 (TLR5) responds to the monomeric form of flagellin and induces the MyD88-depending signaling pathway, activating proinflammatory transcription factors such as NF-κB and the consequent induction of cytokines. On the other hand, HMGB1 is a highly conserved non-histone chromosomal protein shown to interact with and activate TLR5. The present work aimed to design and characterize TLR5 agonist peptides derived from the acidic tail of Salmo salar HMGB1 based on the structural knowledge of the TLR5 surface using global molecular docking platforms. Peptide binding poses complexed on TLR5 ectodomain model from each algorithm were filtrated based on docking scoring functions and predicted theoretical binding affinity of the complex. Circular dichroism spectra were recorded for each peptide selected for synthesis. Only intrinsically disordered peptides (6W, 11W, and SsOri) were selected for experimental functional assay. The functional characterization of the peptides was performed by NF-κB activation assays, RT-qPCR gene expression assays, and Piscirickettsia salmonis challenge in SHK-1 cells. The 6W and 11W peptides increased the nuclear translation of p65 and phosphorylation. In addition, the peptides induced the expression of genes related to the TLR5 pathway activation, pro- and anti-inflammatory response, and differentiation and activation of T lymphocytes towards phenotypes such as TH1, TH17, and TH2. Finally, it was shown that the 11W peptide protects immune cells against infection with P. salmonis bacteria. Overall, the results indicate the usefulness of novel peptides as potential immunostimulants in salmonids.

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Based on the structural knowledge of TLR5 surface and using blind docking platforms, peptides derived from a truncated HMGB1 acidic tail from Salmo salar was designed as TLR5 agonistic. Additionally, a template peptide with the native N-terminal of the acidic tail sequence as a reference was included (SsOri). Peptide binding poses complexed on TLR5 ectodomain model from each algorithm were filtrated based on docking scoring functions and predicted theoretical binding affinity of the complex. The best peptides, termed 6WK and 5LWK, were selected for chemical synthesis and experimental functional assay. The agonist activity by immunoblotting and immunocytochemistry was determined following the NF-κBp65 phosphorylation (p-NF-κBp65) and the nuclear translocation of the NF-κBp65 subunit from the cytosol, respectively. HeLa cells stably expressing a S. salar TLR5 chimeric form (TLR5c7) showed increased p-NF-κBp65 levels regarding extracts from flagellin-treated cells. No statistically significant differences (p > 0.05) were found in the detected p-NF-κBp65 levels between cellular extracts treated with peptides or flagellin by one-way ANOVA. The image analysis of NF-κBp65 immunolabeled cells obtained by confocal microscopy showed increased nuclear NF-κBp65 co-localization in cells both 5LWK and flagellin stimulated, while 6WK and SsOri showed less effect on p65 nuclear translocation (p < 0.05). Also, an increased transcript expression profile of proinflammatory cytokines such as TNFα, IL-1ß, and IL-8 in HKL cells isolated from Salmo salar was evidenced in 5LWK - stimulated by RT-PCR analysis. Overall, the result indicates the usefulness of novel peptides as a potential immunostimulant in S. salar.

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BACKGROUND: Pickering emulsions are a kind of emulsion stabilized by solid particles. These particles generate a physical or mechanical barrier that provides long-term stability to emulsion. Cellulose nanofibers are effective Pickering emulsifiers given their long length, high flexibility and entanglement capability. In this work, soybean hull insoluble polysaccharides (HIPS) were used as source of cellulose nanofibers by using a combination of chemical and mechanical treatment. The chemical composition, morphology, flow behavior, water holding capacity (WHC) and emulsifying properties of the nanofibers were studied. RESULTS: Nanofibers with diameters between 35 and 110 nm were obtained. The WHC increased significantly after the mechanical treatment, and the rheological behavior of the nanofibers was typical of cellulosic materials. Nanofibers were effective emulsifiers in oil-in-water (O/W) emulsions formulated under acidic conditions, without the need of using any additional surfactant. Emulsions were not affected by changes in the pH of the medium (3.00-5.00), and were stable to coalescence. CONCLUSION: It is possible that cellulose nanofibers form an entangled network which acts as a mechanical steric barrier, providing stability to coalescence. These results are important for the development of effective O/W Pickering emulsifiers/stabilizers, with large applications in the food industry. © 2023 Society of Chemical Industry.

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Citrus fruit industrial processing generates tons of waste composed of peels, seeds and pulp. Incorrect disposal of these residues may harm the environment. The extraction of oil and bioactive compounds from citrus fruit seeds may be considered a sustainable alternative to the disposal of waste by the citrus agroindustry. In order to provide safe disposal of citrus waste an evaluation of its composition is necessary. Here we report the results of the application of a methodology to evaluate the composition the seeds of Citrus limettioides. In the first step, extraction with supercritical carbon dioxide was used. This work allowed the isolation and identification of four aglycone-type limonoids by High Performance Liquid Chromatography and Nuclear Magnetic Resonance, identified as limonin, nomilin, deacetylnomilin, and obacunone. In addition, six other polar limonoids and two glycosyl flavonoids were identified by HPLC-ESI/MS/MS.

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Background: This study aimed to characterize potential probiotic strains for use in dogs to prevent infectious enteropathies. Lactic acid bacteria (LAB) isolated from canine milk and colostrum were characterized according to their functional properties, including their resistance to gastrointestinal conditions, inhibitory effect against pathogens, and intestinal adhesion. Methods: The immunomodulatory effects of the strains were also analyzed in in vitro and in vivo studies. Among the strains evaluated, two LAB strains (TUCO-16 and TUCO-17) showed remarkable resistance to pH 3.0, bile salts, and pancreatin, as well as inhibitory effects against pathogenic Escherichia coli, Salmonella sp., and Clostridium perfringens. Results: The TUCO-16 and TUCO-17 strains induced a significant increase in the expression of TNF-α, IL-8, and TLR2 in canine macrophages. The oral administration of TUCO-16 and TUCO-17 strains to mice significantly augmented their resistance to pathogenic E. coli or Salmonella intestinal infections. Both canine strains reduced intestinal damage and pathogen counts in the liver and spleen and avoided their dissemination into the bloodstream. These protective effects were related to the ability of TUCO-16 and TUCO-17 strains to differentially modulate the production of IFN-γ, IFN-ß, TNF-α, IL-6, KC, MCP-1, and IL-10 in the intestinal mucosa. Conclusion: Both strains, TUCO-16 and TUCO-17, are potential probiotic candidates for improving intestinal health in dogs, particularly for their ability to inhibit the growth of Gram-negative pathogens common in gastrointestinal infections and modulate the animal's immune response. Further studies are required to effectively demonstrate the beneficial effects of TUCO-16 and TUCO-17 strains in dogs.

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Monkeypox virus (MPXV), belonging to the Poxviridae family and Orthopoxvirus genus, is closely related to the smallpox virus. Initial prodromal symptoms typically include headache, fever, and lymphadenopathy. This review aims to detail various ocular manifestations and immune evasion associated with the monkeypox viral infection and its complications, making it appropriate as a narrative review. Common external ocular manifestations of MPXV typically involve a generalized pustular rash, keratitis, discharges, and dried secretions related to conjunctival pustules, photophobia, and lacrimation. Orthopoxviruses can evade host immune responses by secreting proteins that antagonize the functions of host IFNγ, CC and CXC chemokines, IL-1ß, and the complement system. One of the most important transcription factors downstream of pattern recognition receptors binding is IRF3, which controls the expression of the crucial antiviral molecules IFNα and IFNß. We strongly recommend that ophthalmologists include MPXV as part of their differential diagnosis when they encounter similar cases presenting with ophthalmic manifestations such as conjunctivitis, blepharitis, or corneal lesions. Furthermore, because non-vaccinated individuals are more likely to exhibit these symptoms, it is recommended that healthcare administrators prioritize smallpox vaccination for at-risk groups, including very young children, pregnant women, older adults, and immunocompromised individuals, especially those in close contact with MPXV cases.

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Pig is one of the most consumed meats worldwide. One of the main conditions for pig production is Porcine Enteropathy caused by Lawsonia intracellularis. Among the effects of this disease is chronic mild diarrhea, which affects the weight gain of pigs, generating economic losses. Vaccines available to prevent this condition do not have the desired effect, but this limitation can be overcome using adjuvants. Pro-inflammatory cytokines, such as interleukin 18 (IL-18), can improve an immune response, reducing the immune window of protection. In this study, recombinant porcine IL-18 was produced and expressed in Escherichia coli and Pichia pastoris. The protein's biological activity was assessed in vitro and in vivo, and we determined that the P. pastoris protein had better immunostimulatory activity. A vaccine candidate against L. intracellularis, formulated with and without IL-18, was used to determine the pigs' cellular and humoral immune responses. Animals injected with the candidate vaccine co-formulated with IL-18 showed a significant increase of Th1 immune response markers and an earlier increase of antibodies than those vaccinated without the cytokine. This suggests that IL-18 acts as an immunostimulant and vaccine adjuvant to boost the immune response against the antigens, reducing the therapeutic window of recombinant protein-based vaccines.

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Previously, we designed a subunit vaccine candidate based on three L. intracellularis antigens with promising results in pigs. In this study, antigens were produced individually to achieve an even antigen ratio in the formulation. The emulsion characterization included the drop size and the mechanical and thermal stability. Immune response was evaluated by indirect and sandwich ELISAs, qPCR, and flow cytometry. The vaccine candidate's safety was assessed by histopathology and monitoring the clinical behavior of animals. The average production yielded for the chimeric antigen as inclusion bodies was around 75 mg/L. The formulation showed mechanical and thermal stability, with a ratio Hu/Ho > 0.85 and a drop size under 0.15 nm. Antigens formulated at a ratio of 1:1:1 induced a significant immune response in inoculated pigs that persisted until the end of the experiment (week 14). The dose of 200 µg significantly activated cellular response measured by transcriptional and translational levels of cytokines. The cell proliferation assay revealed an increment of lymphocytes T CD4+ at the same dose. Animals gained weight constantly and showed proper clinical behavior during immunization assays. This research demonstrated the immunological robustness of the new subunit vaccine candidate against Porcine Proliferative Enteropathy evenly formulated with three chimeric antigens of L. intracellularis.

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Neuropeptides are a group of peptides derived from precursor proteins synthesized in neuronal and nonneuronal cells. The classical functions of neuropeptides have been extensively studied in mammals, including neuromodulation in the central nervous system, molecular signaling in the peripheral nervous system, and immunomodulation associated mainly with anti-inflammatory activity. In contrast, in teleosts, studies of the immunomodulatory function of these neuropeptides are limited. In Oncorhynchus mykiss, vasoactive intestinal peptide (VIP) mRNA sequences have not been cloned, and the role of VIP in modulating the immune system has not been studied. Furthermore, in relation to other neuropeptides with possible immunomodulatory function, such as ghrelin, there are also few studies. Therefore, in this work, we performed molecular cloning, identification, and phylogenetic analysis of three VIP precursor sequences (prepro-VIP1, VIP2 and VIP3) in rainbow trout. In addition, the immunomodulatory function of both neuropeptides was evaluated in an in vitro model using the VIP1 sequence identified in this work and a ghrelin sequence already studied in O. mykiss. The results suggest that the prepro-VIP2 sequence has the lowest percentage of identity with respect to the other homologous sequences and is more closely related to mammalian orthologous sequences. VIP1 induces significant expression of both pro-inflammatory (IFN-γ, IL-1ß) and anti-inflammatory (IL-10 and TGF-ß) cytokines, whereas ghrelin only induces significant expression of proinflammatory cytokines such as IL-6 and TNF-α.

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Abstract Objective: The objective of the study was to establish the prognostic value of CSNRT regarding the necessity for pacemaker implantation in patients with atrial flutter (AFL) post-ablation. Methods: This prospective cohort study, conducted at the National Institute of Cardiology "Ignacio Chavez" in Mexico City, assessed patients who had undergone ablation procedures to correct AFL, posterior to which an autonomic blockade was performed, and CSNRT was measured. Results: The sample for this investigation was 40 patients. These were subdivided into two study groups depending on their requirement of pacemaker implant post-ablation (Pacemaker P, No Pacemaker NP). Sinus node (SN) dysfunction was diagnosed in 13 (32.5%) of the 40 participants, 10 (71.43%) of which required a pacemaker implant, while only 4 participants (28.57%) with normal SN function required pacemakers. Ten out of the 14 patients (71.43%) who required a pacemaker had an elevated CSNRT > 500 ms (p ≤ 0.01). Post-ablation CSNRT mean was 383.54 ms ± 67.96 ms in the NP group versus 1972.57 ms ± 3423.56 ms in the P group. Furthermore, SN pause in the P group had a mean of 1.86 s ± 0.96 s versus the NP group with 1.196 s ± 0.52 s. Conclusion: CSNRT has the potential to be a quantitative prognostic tool for the assessment of future pacemaker implants in patients with AFL post-ablation. This could aid in the timely diagnosis of sinus node dysfunction, which could, in the long run, result in the reduction of cardiac functional capacity loss due to cardiac remodeling.

Resumen Objetivo: Establecer el valor pronóstico del TRNSC basado en la necesidad de marcapasos en pacientes diagnosticados con aleteo atrial, pos-ablación. Métodos: Este cohorte prospectivo, realizado en el Instituto Nacional de Cardiología "Ignacio Chávez" en la Ciudad de México, evaluó pacientes sometidos a ablación para corregir el aleteo atrial; se midió el TRNSC post bloqueo autonómico. Resultados: La muestra de 40 pacientes se subdividió en 2 grupos según su requerimiento de marcapasos posterior a la ablación (P y NP). Se diagnosticó disfunción del nodo sinusal en 13 participantes (32.5%), de los cuales 10 (71.43%) requirieron marcapasos en comparación a 4 (28.57%) con función normal. En el grupo P la pausa del nodo sinusal post-ablación tuvo una media de 1.86 ± 0.96 s versus el grupo NP con 1.196 ± 0.52 s. En relación con el TRNSC, el grupo NP tuvo una media de 383.54 ± 67.96 ms vs. 1972.57 ± 3423.56 ms en el grupo P. 10 pacientes (25%) obtuvieron un TRNSC > 500 ms, de los cuales 100% requirieron marcapasos; de los 14 pacientes que requirieron marcapasos 10 (71.43%) tenían un TRNSC elevado (p ≤ 0.01). Conclusiones: El TRNSC tiene el potencial de ser una herramienta de pronóstico cuantitativo para la necesidad de futuros implantes de marcapasos en pacientes con disfunción del nodo sinusal, resultado de aleteo atrial pos-ablación. Esto podría ayudar a diagnosticar más temprano una disfunción del nodo sinusal, resultando en la reducción de la pérdida a largo plazo de la función cardíaca como efecto de la remodelación.

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The use of goats for meat production faces challenges from environmental and nutritional factors. Urea is an affordable non-protein nitrogen source commonly utilized in ruminant nutrition. The objective of this study was to investigate nitrogen utilization in goats fed low-quality hay supplemented with molasses blocks containing urea. Twenty Anglo-Nubian doelings were individually housed in metabolic cages and provided with chopped Buffelgrass (Cenchrus ciliaris) hay ad libitum. Goats were randomly assigned to four urea levels (0, 2, 4, and 6%; n = 5 per treatment) in molasses blocks for a duration of 30 days. A negative nitrogen balance (-2.458 g/day) was observed in doelings consuming blocks without urea, compared with a positive balance (0.895 g/d) for those consuming the 6% urea blocks. Block nitrogen intake significantly increased with urea level, but urea supplementation did not affect dry matter (DM) or neutral detergent fiber (NDFom) intake or digestibility. A minimum crude protein (CP) requirement of 8% for maintenance in doelings consuming low-quality forage with a urea-based supplement was determined through regression analysis between CP intake (% of DM) and N balance (r2 = 0.479; p < 0.002). The value of 8% of CP obtained in this study is similar to several previous studies reported in the literature, but in this case, the increments in CP came exclusively from urea. In this study, increasing the urea content of molasses blocks up to 6% significantly increased nitrogen intake, retention, and balance in goats. These results contribute to a better understanding of nitrogen utilization in goats fed low-quality hay with urea supplementation.