RESUMO
The formation of complex three-dimensional organs during development requires precise coordination between patterning networks and mechanical forces. In particular, tissue folding is a crucial process that relies on a combination of local and tissue-wide mechanical forces. Here, we investigate the contribution of cell proliferation to epithelial morphogenesis using the Drosophila leg tarsal folds as a model. We reveal that tissue-wide compression forces generated by cell proliferation, in coordination with the Notch signaling pathway, are essential for the formation of epithelial folds in precise locations along the proximo-distal axis of the leg. As cell numbers increase, compressive stresses arise, promoting the folding of the epithelium and reinforcing the apical constriction of invaginating cells. Additionally, the Notch target dysfusion plays a key function specifying the location of the folds, through the apical accumulation of F-actin and the apico-basal shortening of invaginating cells. These findings provide new insights into the intricate mechanisms involved in epithelial morphogenesis, highlighting the crucial role of tissue-wide forces in shaping a three-dimensional organ in a reproducible manner.
Assuntos
Proliferação de Células , Proteínas de Drosophila , Drosophila , Receptores Notch , Animais , Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Epitélio/metabolismo , Morfogênese/genética , Transdução de Sinais , Receptores Notch/metabolismoRESUMO
The aim of this study was to examine the impact of daily calcium propionate (CaPr) supplementation (0 or 20 g/calf) on growth performance, dietary energetics, body fat reserves, serum metabolites, and hematological responses in high-risk beef calves fed diets with varying (50, 60, or 70%) concentrate (CON) levels. In addition, a cost/income analysis of CaPr supplementation was carried out. Forty-eight crossbred bull calves (152.8 ± 1.56 kg body weight and 5.5 months of age) were involved in a fully randomized experimental design employing a 2 × 3 factorial arrangement of treatments. Calves were allocated (n = 8 per treatment) to individual pens (3.14 × 5.25 m) and were subjected to one of the following treatments during 42 d: No CaPr supplementation in diets containing 50, 60, or 70% CON (NoCaPr + 50, NoCaPr + 60, NoCaPr + 70, respectively) or daily CaPr supplementation dosed at 20 g/calf in diets containing 50, 60, or 70% CON (20CaPr + 50, 20CaPr + 60, 20CaPr + 70, respectively). Non-supplemented calves exhibited decreased dry matter intake (DMI) with increasing CON levels in their diets, while CaPr-supplemented calves displayed the opposite effect (interaction, p = 0.04). In calves fed a lower-CON diet (50%), those supplemented with CaPr showed greater average daily gain (ADG, 20.2%, p = 0.05) and lower DMI (2.2%, p = 0.03), resulting in improved ADG/DMI ratio, dietary energy, and energy retention (24.6, 14.4, and 18%, p < 0.05). These effects diminished when calves received diets with 60 or 70% CON but led to a 14.2% increase in rump fat thickness (p = 0.04). Only in non-supplemented CaPr calves, increasing the level of CON from 50 to 70% in the diet increased ADG (21.2%), decreased DMI (2.2%), and improved the ADG/DMI ratio (22.7%), with no impact on dietary net energy utilization. Non-supplemented calves exhibited an increase in lymphocytes as CON levels rose in their diets, whereas CaPr-supplemented calves showed the opposite effect (interaction, p = 0.05). Supplementation of CaPr decreased total protein (TP, p = 0.03) and albumin (ALB, p < 0.01) serum concentrations, with lower concentrations observed in 20CaPr + 50. CaPr supplementation reduced (p = 0.01) total cholesterol (TCHO) levels. An interaction between CaPr and CON level (p = 0.02) was observed since TCHO levels remained consistently low at higher CON levels. Glucose was decreased with increasing levels of CON (p = 0.02) but not (p = 0.85) for CaPr-supplemented calves. NoCaPr + 50 and NoCaPr + 70 increased (p = 0.05) ALB concentration. Gamma glutamyltransferase levels increased (p = 0.05) with increasing CON levels irrespective of CaPr supplementation. Comparing the profit within the same CON level in the diet, CaPr treatments yielded higher income, with the largest difference in profit observed when CaPr was supplemented at 50% CON level (USD 29 more/calf). In conclusion, CaPr supplementation proves to be an effective strategy for enhancing growth performance and dietary energy among high-risk beef calves, resulting in greater economic returns. The groups that received CaPr demonstrated superior profitability, particularly in calves fed diets with lower CON levels. Under the conditions in which this experiment was carried out, the optimal response occurred when the low-CON diet (50%) was supplemented with CaPr.
RESUMO
Enzymic activity, metabolites, and hematological responses for reference intervals (RIs) establish ranges of physiological normality, which are useful for diagnosing diseases and physiological alterations. Within the same species, RIs vary according to age, gender, productive and physiological states, and environmental factors including health management and nutrition. RIs have been extensively studied in dairy calves during a critical stage of life (from birth up to first 90 days of age). A critical stage for feedlot calves is their arrival at the feedlot, but no reports determine RIs for different enzymic activity, metabolites, and hematological responses during their initial period at the feedlot. Consequently, a total of 461 high-risk crossbreed beef calves, received on three different dates, were examined upon arrival at the feedlot. Of these, 320 calves (148.3 ± 1.3 kg body weight) whose "clinical health" was evaluated were included in the study. Blood samples were taken upon arrival and on days 14, 28, 42, and 56 to determine the following parameters: enzymic activity, metabolites, electrolytes, white blood cells, platelets, and red blood cells. Enzymic activity, metabolites, and complete blood count were determined by automated analyzers. The freeware Reference Value Advisor Software was used to calculate the non-parametric values of RIs. This study is the first to establish RIs for different enzymic activity, metabolites, and hematological responses in high-risk newly received calves during their initial period at the feedlot. This information will be useful for veterinary clinical practice and research related to the health and welfare of high-risk newly received calves during their initial period at the feedlot.
RESUMO
Enhancement of antivenom immune responses in horses through adjuvant technology improves antivenom production efficiency, but substantial local reactogenicity associated with some traditional veterinary adjuvants limits their usability. To explore modern adjuvant systems suitable for generating antivenom responses in horses, we first assessed their physicochemical compatibility with Bothrops asper snake venom. Liposome and nanoparticle aluminum adjuvants exhibited changes in particle size and phospholipid content after mixing with venom, whereas squalene emulsion-based adjuvants remained stable. Next, we evaluated serum antibody response magnitude and neutralization capacity in horses immunized with adjuvant-containing Echis ocellatus, Bitis arietans, Naja nigricollis, and Dendroaspis polylepis venom preparations. Whereas all tested adjuvants elicited significant neutralization capacity against the viperid venoms, the greatest antibody responses were generated by a squalene-in-water emulsion, thus representing a promising novel alternative for antivenom production.
Assuntos
Antivenenos , Viperidae , Cavalos , Animais , Antivenenos/farmacologia , Emulsões , Esqualeno , Venenos de Serpentes , Adjuvantes Imunológicos/farmacologia , ImunizaçãoRESUMO
BACKGROUND: Snakebite envenomation exerts a heavy toll in sub-Saharan Africa. The design and production of effective polyspecific antivenoms for this region demand a better understanding of the immunological characteristics of the different venoms from the most medically important snakes, to select the most appropriate venom combinations for generating antivenoms of wide neutralizing scope. Bitis spp. and Echis spp. represent the most important viperid snake genera in Africa. METHODOLOGY/PRINCIPAL FINDINGS: Eight rabbit-derived monospecific antisera were raised against the venoms of four species of Bitis spp. and four species of Echis spp. The effects of immunization in the rabbits were assessed, as well as the development of antibody titers, as judged by immunochemical assays and neutralization of lethal, hemorrhagic, and in vitro coagulant effects. At the end of immunizations, local and pulmonary hemorrhage, together with slight increments in the plasma activity of creatine kinase (CK), were observed owing to the action of hemorrhagic and myotoxic venom components. Immunologic analyses revealed a considerable extent of cross-reactivity of monospecific antisera against heterologous venoms within each genus, although some antisera provided a more extensive cross-reactivity than others. The venoms that generated antisera with the broadest coverage were those of Bitis gabonica and B. rhinoceros within Bitis spp. and Echis leucogaster within Echis spp. CONCLUSIONS/SIGNIFICANCE: The methodology followed in this study provides a rational basis for the selection of the best combination of venoms for generating antivenoms of high cross-reactivity against viperid venoms in sub-Saharan Africa. Results suggest that the venoms of B. gabonica, B. rhinoceros, and E. leucogaster generate antisera with the broadest cross-reactivity within their genera. These experimental results in rabbits need to be translated to large animals used in antivenom production to assess whether these predictions are reproduced in horses or sheep.
Assuntos
Viperidae , África Subsaariana , Animais , Antivenenos , Hemorragia , Cavalos , Soros Imunes , Coelhos , Ovinos , Venenos de Serpentes , SerpentesRESUMO
Adjuvant emulsions are widely used to enhance the antibody response in animals used as immunoglobulin source to produce snake antivenoms. We tested the performance of four commercial emulsion adjuvants (Montanide, Freund, Carbigen, and Emulsigen-D) and an experimental adjuvant (QH-769) in the antibody response of horses towards venoms of the African snakes Bitis arietans, Echis ocellatus, Dendroaspis polylepis and Naja nigricollis. Montanide, Freund and Carbigen adjuvants generated the highest immune response but induced moderate/severe local lesions at the site of injection. In contrast, Emulsigen-D and QH-769 adjuvants generated the lowest immune response and low incidence of local lesions. No evidence of systemic alterations was observed in the horses immunized with any of the adjuvants. It is suggested that the use of Montanide or Freund-based emulsions in the first immunization steps, followed by the use of Emulsigen-D, QH-769 or similar adjuvants in the following injections, could result in a satisfactory immune response against snake venoms, while not inducing serious local deleterious effects.
RESUMO
The lethality neutralization assay in mice is the gold standard for the evaluation of the preclinical efficacy and specification fulfillment of snake antivenoms. However, owing to the animal suffering involved, this assay is a candidate to be replaced by in vitro alternatives or, at least, improved by the reduction of the number of animals used per experiment, the introduction of analgesia, and the refinement of the test. Since these tests are usually run for 24 or 48 h, one possibility to refine it is to shorten the endpoint observation time of the assay and so limiting the duration of suffering. To assess the effect of this modification of the standard procedure on the analytical properties of the assay, we compared the median lethal dose (LD50) and median effective dose (ED50) values, estimated through observation times of 6, 24 and 48 h. We used African and Latin American snake venoms and several batches of two polyspecific antivenoms. A significant correlation was found between LD50 and ED50 values estimated at the three observation times. Although some LD50 and ED50 values were significantly different at these time points, results of 6 h were robust enough to be used in the characterization of new antivenoms, the verification of specification compliance, and the parallel comparison of formulations. Our observations support the modification of the standard procedures used for assessing neutralizing ability of antivenoms by carrying out the observations at 6 h instead of 24 or 48 h, with the consequent reduction in the suffering inflicted upon mice during these assays. However, the shortening of the observation time in the lethality tests must be validated for each venom and antivenom before its introduction in the routine procedures.
RESUMO
OBJECTIVE: During this year, in relation to the health crisis triggered by COVID-19, a total of 532 people have been evaluated by the Teaching Staff Prevention Service of the Ministry of Education and Vocational Training of the Balearic Islands, most of them which were women, as is usually the case in the teaching community. After some time of reflection, there are some questions that we would like to answer, such as knowing the most frequent pathologies with vulnerability to COVID-19 in our service and the work adaptations made. To answer these questions, we carried out this descriptive study. METHODS: This study was made with sample of 508 people from Prevention Service of teachers during the course 2020-2021. We studied differences between sex, age, job, developed actuation, pathology. Statistical calculations were performed with Libreoffice's numerical calculation processor. RESULTS: From the several pathologies included among the vulnerable groups to COVID-19 according to the Health Ministry, the one with more prevalence is chronic pulmonar disease (25.39%). CONCLUSIONS: The pulmonar disease is the most frequent in our study, but due to the presence of many workers with pluripathology, this datum should be keepen in mind with some caution.
OBJETIVO: Durante este año, en relación a la crisis sanitaria desencadenada por la COVID-19, desde el Servicio de Prevención del Personal Docente de la Conselleria de Educación y Formación Profesional de las Islas Baleares se han evaluado un total de 532 personas, la mayoría de las cuales eran mujeres, como suele ser en el colectivo de la docencia. Existen ciertas cuestiones a las que intentamos dar respuesta, como es saber las patologías más frecuentes que han hecho reconocer una vulnerabilidad a COVID-19 en nuestro servicio y las consecuencias que han tenido en cuanto a las adaptaciones laborales establecidas. Para dar respuesta a estas cuestiones, realizamos este estudio descriptivo. METODOS: El estudio se desarrolló con una muestra de 508 personas del Servicio de Prevención del Personal Docente de Palma durante el curso 2020-2021. Para lo cual evaluamos las diferencias según sexo, edad, puesto de trabajo, actuación llevada a cabo y patología. Los cálculos estadísticos se realizaron con el procesador de cálculo numérico de Libreoffice. RESULTADOS: Del desglose de las patologías incluidas dentro de los grupos vulnerables frente a COVID-19 según el Ministerio de Sanidad, la más prevalente fue la enfermedad pulmonar crónica (25,39%). CONCLUSIONES: La patología pulmonar fue la más frecuente de nuestro estudio, pero debido a la presencia de muchos trabajadores con pluripatología, este dato debe ser tenido en cuenta con cierta cautela.
Assuntos
COVID-19 , Feminino , Pessoal de Saúde , Humanos , SARS-CoV-2 , EspanhaRESUMO
Despite vaccines are the main strategy to control the ongoing global COVID-19 pandemic, their effectiveness could not be enough for individuals with immunosuppression. In these cases, as well as in patients with moderate/severe COVID-19, passive immunization with anti-SARS-CoV-2 immunoglobulins could be a therapeutic alternative. We used caprylic acid precipitation to prepare a pilot-scale batch of anti-SARS-CoV-2 intravenous immunoglobulins (IVIg) from plasma of donors immunized with the BNT162b2 (Pfizer-BioNTech) anti-COVID-19 vaccine (VP-IVIg) and compared their in vitro efficacy and safety with those of a similar formulation produced from plasma of COVID-19 convalescent donors (CP-IVIg). Both formulations showed immunological, physicochemical, biochemical, and microbiological characteristics that meet the specifications of IVIg formulations. Moreover, the concentration of anti-RBD and ACE2-RBD neutralizing antibodies was higher in VP-IVIg than in CP-IVIg. In concordance, plaque reduction neutralization tests showed inhibitory concentrations of 0.03-0.09 g/L in VP-IVIg and of 0.06-0.13 in CP-IVIg. Thus, VP-IVIg has in vitro efficacy and safety profiles that justify their evaluation as therapeutic alternative for clinical cases of COVID-19. Precipitation with caprylic acid could be a simple, feasible, and affordable alternative to produce formulations of anti-SARS-CoV-2 IVIg to be used therapeutically or prophylactically to confront the COVID-19 pandemic in middle and low-income countries.
RESUMO
In the current global emergency due to SARS-CoV-2 outbreak, passive immunotherapy emerges as a promising treatment for COVID-19. Among animal-derived products, equine formulations are still the cornerstone therapy for treating envenomations due to animal bites and stings. Therefore, drawing upon decades of experience in manufacturing snake antivenom, we developed and preclinically evaluated two anti-SARS-CoV-2 polyclonal equine formulations as potential alternative therapy for COVID-19. We immunized two groups of horses with either S1 (anti-S1) or a mixture of S1, N, and SEM mosaic (anti-Mix) viral recombinant proteins. Horses reached a maximum anti-viral antibody level at 7 weeks following priming, and showed no major adverse acute or chronic clinical alterations. Two whole-IgG formulations were prepared via hyperimmune plasma precipitation with caprylic acid and then formulated for parenteral use. Both preparations had similar physicochemical and microbiological quality and showed ELISA immunoreactivity towards S1 protein and the receptor binding domain (RBD). The anti-Mix formulation also presented immunoreactivity against N protein. Due to high anti-S1 and anti-RBD antibody content, final products exhibited high in vitro neutralizing capacity of SARS-CoV-2 infection, 80 times higher than a pool of human convalescent plasma. Pre-clinical quality profiles were similar among both products, but clinical efficacy and safety must be tested in clinical trials. The technological strategy we describe here can be adapted by other producers, particularly in low- and middle-income countries.