Antifungal biomaterial for reducing infections caused by Candida albicans in edentulous patients.

INTRODUCTION: Polymethylmethacrylate (PMMA) acrylic resins are used to make dentures for edentulous patients. OBJECTIVE: To find out the prevalence of Candida species in patients with and without removable prostheses from a dental clinic in León, Guanajuato, as well as to assess the antifungal effect and biological behavior of an experimental PMMA with silver nanoparticles for its possible application in prostheses. METHOD: To identify Candida species, smear samples were obtained from the palatal mucosa of 140 patients aged ≥ 60 years. The experimental PMMA with silver nnoparticles was placed in Candida albicans cultures, which were stained with the Live/Dead® kit for analysis under confocal microscopy; subsequently, it was implanted in Wistar rats in order to know its behavior in the surrounding tissues. RESULTS: Candida albicans was the most prevalent species in the evaluated patients, followed by Candida tropicalis and Candida krusei. The acrylic resin with silver nanoparticles significantly decreased the presence of Candida albicans. In the animal model, a discrete and controlled inflammatory reaction was found, which indicated biocompatibility of the acrylic resin that was used. CONCLUSIONS: It is possible for the nanostructured material with antifungal effect to be used in order to promote the reduction of oral Candida infections in edentulous patients.

INTRODUCCIÓN: Las resinas acrílicas de polimetilmetacrilato (PMMA) son utilizadas para elaborar dentaduras para pacientes edéntulos. OBJETIVO: Conocer la prevalencia de las especies de Candida en pacientes con y sin prótesis removibles de una clínica de odontología en León, Guanajuato; así como valorar el efecto antifúngico y el comportamiento biológico de un PMMA experimental con nanopartículas de plata para su posible aplicación en prótesis. MÉTODO: Para identificar las especies de Candida se obtuvieron muestras para frotis de la mucosa palatina de 140 pacientes con edad ≥ 60 años. El PMMA experimental con nanopartículas de plata fue colocado en cultivos de Candida albicans, los cuales fueron teñidos con el kit Live/Dead® para su análisis bajo microscopia confocal; posteriormente, se implantó en ratas Wistar para conocer su comportamiento en los tejidos circundantes. RESULTADOS: Candida albicans fue la especie más prevalente en los pacientes valorados, seguida de Candida tropicalis y Candida krusei. La resina acrílica con nanopartículas de plata disminuyó significativamente la presencia de Candida albicans. En el modelo animal se encontró reacción inflamatoria discreta y controlada, lo cual indicó la biocompatibilidad de la resina acrílica utilizada. CONCLUSIONES: Es posible utilizar el material nanoestructurado con efecto antifúngico para promover la reducción de infecciones orales por Candida en pacientes edéntulos.

Experimental infection of sheep with Bovine leukemia virus (BLV): Minimum dose of BLV-FLK cells and cell-free BLV and neutralization activity of natural antibodies.

Bovine leukemia virus (BLV) is an important cattle pathogen that causes major economic losses worldwide, especially in dairy farms. The use of animal models provides valuable insight into the pathogenesis of viral infections. Experimental infections of sheep have been conducted using blood from BLV-infected cattle, infectious BLV molecular clones or tumor-derived cells. The Fetal Lamb Kidney cell line, persistently infected with BLV (FLK-BLV), is one of the most commonly used long-term culture available for the permanent production of virus. FLK-BLV cells or the viral particles obtained from the cell-free culture supernatant could be used as a source of provirus or virus to experimentally infect sheep. In this report, we aimed to determine the minimum amount of FLK-BLV cells or cell-free supernatant containing BLV needed to produce infection in sheep. We also evaluated the amount of antibodies obtained from a naturally-infected cow required to neutralize this infection. We observed that both sheep experimentally inoculated with 5000 FLK-BLV cells became infected, as well as one of the sheep receiving 500 FLK-BLV cells. None of the animals inoculated with 50 FLK-BLV cells showed evidence of infection. The cell-free FLK-BLV supernatant proved to be infective in sheep up to a 1:1000 dilution. Specific BLV antibodies showed neutralizing activity as none of the sheep became infected. Conversely, the animals receiving a BLV-negative serum showed signs of BLV infection. These results contribute to the optimization of a sheep bioassay which could be useful to further characterize BLV infection.

Combining two antifungal agents does not enhance survival of Galleria mellonella larvae infected with Madurella mycetomatis.

OBJECTIVE: To determine whether combination therapy would improve therapeutic outcome in eumycetoma caused by Madurella mycetomatis. METHODS: Survival, colony-forming units (CFU), melanisation and histopathology in M. mycetomatis-infected Galleria mellonella larvae treated with amphotericin B, itraconazole, terbinafine or combinations thereof were determined. RESULTS: Compared to larvae treated with 5% glucose, enhanced survival was obtained when M. mycetomatis-infected larvae were treated with amphotericin B, but not when they were treated with itraconazole or terbinafine. Combination therapy did not increase survival compared to 5% glucose-treated larvae, itraconazole-treated larvae or terbinafine-treated larvae. Compared to amphotericin B monotreatment, a significant decrease in survival was noted when this therapy was combined with either itraconazole or terbinafine. CFU, melanisation and histopathology did not differ between monotherapy, combination therapy or 5% glucose-treated larvae. CONCLUSIONS: Combining different classes of antifungal agents did not enhance the survival of M. mycetomatis-infected G. mellonella larvae. Instead of improving the therapeutic outcome, combining either itraconazole or terbinafine with amphotericin B resulted in significantly lower survival rates of infected larvae than amphotericin B monotherapy. This experimental study does not provide support for the use of combined amphotericin B and itraconazole, combined itraconazole and terbinafine or combined terbinafine and amphotericin B and should be confirmed in other animal models.

Taphonomy of experimental burials in Taphos-m: The role of fungi.

BACKGROUND: The fungi present in the decaying remains enable a better understanding of the processes of decomposition after death. There are not many studies about fungi on decaying bodies and it is not known which fungal sampling methods are effective. AIMS: The main objective of this study was to find the best method for sampling fungi in carcasses, prove the effectiveness of this method and identify the fungal colonies in animal carcasses from experimental burials. METHODS: Samples from 13 carcasses of Sus scrofa domestica, from the experimental project Taphos-m, were taken with different materials: spatula, sterile swabs and RODAC contact plates. RESULTS: RODAC contact plates with the RBA culture medium showed higher proliferation of fungal colonies. Thirty genera of fungi were isolated from different substrates (bone, tissue, lime). Most of the fungi genera or groups identified have been described before in the literature, but the substrates they came from were different in some cases. CONCLUSIONS: Sampling with RODAC contact plates was found to be the most effective method, as it provides a nutritional culture medium that may allow growth since the moment of sampling. Fungi colonies grew better in RBA culture medium because bacterial growth is inhibited. Most of the observed fungi are related to the environment but some others have been found related to decomposing bodies for the first time.

Reactivity Study of a Biodegradable Polydioxanone Tracheal Stent in a Rabbit Model. / Stent traqueal biodegradable de polidioxanona. Estudio de la reactividad en conejo.

INTRODUCTION: The objective of this study was to evaluate tracheal reactivity induced by a biodegradable polydioxanone tracheal stent. MATERIALS AND METHODS: Twenty-two rabbits were divided into 3 groups assigned to different survival times (30, 60 and 90days post-implantation). A biodegradable stent was implanted in each animal, except for 1 of each group (negative control). Implantation was performed through a small tracheotomy under fluoroscopic control. CT and histopathological studies were scheduled at the end of survival times. RESULTS: No animal died during the procedure or follow-up. The stent had disappeared in 100% of the cases at 90days, in 50% at 60days, and in none at 30days. CT studies revealed a greater tracheal wall thickness at 30days than at 60 and 90days (1.60±0.41mm in the central part of the stent versus 1.11±0.18 and 0.94±0.11; P=.007, respectively). No granulomas were observed on histopathology. Some degree of histological changes were noted at 30days, which had reduced at 60 and 90days. Differences were also found in both CT and histology between animals in which the stent was present and animals in which it had degraded. CONCLUSIONS: Polydioxanone stents produce a mild reaction that reverts with tracheal degradation. The use of these biodegradable stents in benign tracheal disease is promising.

Bone Marrow-derived Mesenchymal Stem Cells and Chronic Allograft Disease in a Bronchiolitis Obliterans Animal Model.

INTRODUCTION: Bronchiolitis obliterans (BO) is the most common expression of chronic allograft dysfunction in lung transplantation. Moreover, BO represents the major cause of death in the long-term after this procedure. On the other hand, mesenchymal stem cells have been tested in animal models of BO aiming to interfere in its development. The aim of this experimental study is to explore the role of bone-marrow derived stem cells (BMSCs) as a preventive intervention of BO occurrence. MATERIALS AND METHODS: This an experimental randomized study. A bronchiolitis obliterans animal model in rats was reproduced: heterotopical tracheal transplant model in lung parenchyma. Five of these animals were used as control group. After setting up the model, individuals were divided in 3 groups of treatment (n=15), in which BMSCs were administered in 3 different time points after the tracheal transplant (tracheal transplantation and BMSCs administration occurred the same day, group G0; after 7 days, group G7; after 14 days, group G14. In addition, within each group, BMSCs were administered through 3 different routes: endotracheally, endovascular and topically in the lung parenchyma). Animals were sacrificed at 21 days. Histology, fluorescence in situ hybridization and immunohistochemistry techniques were performed for identifying stem cells. RESULTS: Compared to control group, animals receiving BMSCs showed large neovessels in a loose fibrous matrix. Group G7 showed less fibrosis (p<0.033) and edema (p<0.028). Moreover, G7 animals receiving stem cells endotracheally showed no fibrosis (p<0.008). Alveolar-like patches of tissue were observed among all groups (53.4%, 46.7% and 40% in G0, G7 and G14 respectively), consisting of cells expressing both stem and alveolar cells biomarkers. CONCLUSION: BMSCs modify the course of bronchiolitis obliterans and differentiate into alveolar cells. Endotracheal administration of BMSCs 7 days after the heterotopical tracheal transplant might be considered an effective way to prevent BO in this animal model.

Antifungal susceptibility of Saccharomyces cerevisiae and therapy in a murine model of disseminated infection.

BACKGROUND: The incidence of systemic infections by Saccharomyces cerevisiae has increased in recent years, especially among immunocompromised patients. Amphotericin B, voriconazole or echinocandins have been used with favorable outcome against systemic infections by this fungus. However, clinical experience is limited and no in vivo studies have been conducted. AIMS: We evaluated the in vitro activity of nine antifungal compounds against S.cerevisiae and the in vivo efficacy of those three antifungals showing the highest in vitro activity by using a murine model of systemic infection. METHODS: Minimal inhibitory concentrations (MICs) were determined by the microdilution method against three strains of S. cerevisiae. After intravenous infection with 5×107 CFUs, animals received liposomal amphotericin B (5mg/kg), voriconazole (25mg/kg) or anidulafungin (5mg/kg). Treatment efficacy was assessed by determining of CFUs/g in liver, kidney, brain, lung and spleen. RESULTS: 5-Fluorocytosine was the most in vitro active compound followed by amphotericin B, voriconazole and anidulafungin. The in vivo study showed that liposomal amphotericin B was the most effective drug driving highest fungal clearance. CONCLUSIONS: All treatments reduced the fungal load in comparison to the control group, being liposomal amphotericin B the most effective drug followed by anidulafungin and finally voriconazole.

Experimental study of the application of a new bone cement loaded with broad spectrum antibiotics for the treatment of bone infection. / Estudio experimental de la aplicación de un nuevo cemento óseo cargado con antibióticos de amplio espectro para el tratamiento de la infección ósea.

OBJECTIVES: To evaluate the in vivo behaviour of a new bone cement loaded with antibiotics, in a rabbit bone infection model. MATERIAL AND METHODS: Sixteen New Zealand rabbits divided into 4 groups were used, depending on the cement (commercial or experimental) and the antibiotic (vancomycin or linezolid) used to control a bone infection caused by Staphylococcus aureus. The commercial cement is Palacos® R and the experimental cement has been achieved by adding PLGA to the solid phase of Palacos® R cement. A novel histological staging method based on bone histoarchitecture has been used. This staging allows us a global vision of bone repair capacity, in the presence of modified cement, and also allows us to correlate the damage generated with the functionality of the tissue. RESULTS: The degree of bone destructuration found depended on the type of cement and antibiotic, and was higher in the groups with commercial cement than in the experimental group (P<.01) and in the groups with linezolid with respect to vancomycin (P=.04) The percentage of macrophages varied exclusively depending on the antibiotic used, and was higher in the vancomycin groups (P=.04). DISCUSSION: The development of new formulations of bone cement that release more, and more prolonged, new generation antibiotics such as linezolid, present an in vivo behaviour superior to commercial cement, respecting the bone structure. This behaviour would have a clinical implication in fighting infections by increasingly resistant germs in the treatment of prosthetic infection.

Comparação da microbiota intestinal em modelos animais de doença hepática esteatótica alcoólica e metabólica / Comparison of gut microbiota in alcoholic and metabolic-dysfuncion associated steatotic liver disease in animal models

ABSTRACT Background: Alcoholic liver disease (ALD) and metabolic-dysfunction associated steatotic liver disease (MASLD) are common, and gut microbiota (GM) is involved with both. Here we compared GM composition in animal models of MASLD and ALD to assess whether there are specific patterns for each disease. Methods: MASLD model- adult male Sprague Dawley rats, randomized into two groups: MASLD-control (n=10) fed a standard diet; MASLD-group (n=10) fed a high-fat-choline-deficient diet for 16 weeks. ALD model- adult male Wistar rats randomized: ALD-control (n=8) fed a standard diet and water+0.05% saccharin, ALD groups fed with sunflower seed and 10% ethanol+0.05% saccharin for 4 or 8 weeks (ALC4, n=8; ALC8, n=8). ALC4/8 on the last day received alcoholic binge (5g/kg of ethanol). Afterwards, animals were euthanized, and feces were collected for GM analysis. Results: Both experimental models induced typical histopathological features of the diseases. Alpha diversity was lower in MASLD compared with ALD (p<0.001), and structural pattern was different between them (P<0.001). Bacteroidetes (55.7%), Firmicutes (40.6%), and Proteobacteria (1.4%) were the most prevalent phyla in all samples, although differentially abundant among groups. ALC8 had a greater abundance of the phyla Cyanobacteria (5.3%) and Verrucomicrobiota (3.2%) in relation to the others. Differential abundance analysis identified Lactobacillaceae_unclassified, Lachnospiraceae_NK4A136_group, and Turicibacter associated with ALC4 and the Clostridia_UCG_014_ge and Gastranaerophilales_ge genera to ALC8. Conclusion: In this study, we demonstrated that the structural pattern of the GM differs significantly between MASLD and ALD models. Studies are needed to characterize the microbiota and metabolome in both clinical conditions to find new therapeutic strategies.

RESUMO Contexto: A doença hepática alcoólica (DHA) e a doença hepática esteatótica associada à disfunção metabólica (MASLD) são comuns, e a microbiota intestinal (MI) está envolvida em ambas. Aqui, comparamos a composição da MI em modelos animais de MASLD e DHA para avaliar se existem padrões específicos para cada doença. Métodos: Modelo de MASLD - ratos machos adultos da linhagem Sprague Dawley, randomizados em dois grupos: MASLD-controle (n=10) alimentados com uma dieta padrão; grupo MASLD (n=10) alimentados com uma dieta rica em gordura e deficiente em colina por 16 semanas. Modelo de DHA - ratos machos adultos da linhagem Wistar randomizados: DHA-controle (n=8) alimentados com uma dieta padrão e água+0,05% de sacarina; grupos DHA alimentados com semente de girassol e 10% de etanol+0,05% de sacarina por 4 ou 8 semanas (DHA4, n=8; DHA8, n=8). DHA 4/8 no último dia receberam binge alcoólico (5 g/kg de etanol). Posteriormente, os animais foram sacrificados, e as fezes foram coletadas para análise da MI. Resultados: Ambos os modelos experimentais induziram características histopatológicas típicas das doenças. A diversidade alfa foi menor na MASLD em comparação com a DHA (P<0,001), e o padrão estrutural foi diferente entre elas (P<0,001). Bacteroidetes (55,7%), Firmicutes (40,6%) e Proteobactérias (1,4%) foram os filos mais prevalentes em todas as amostras, embora com abundâncias diferenciadas entre os grupos. DHA8 teve uma maior abundância dos filos Cyanobacteria (5,3%) e Verrucomicrobiota (3,2%) em relação aos outros. A análise de abundância diferencial identificou Lactobacillaceae_unclassified, Lachnospiraceae_NK4A136 e Turicibacter associados ao grupo DHA4, e os gêneros Clostridia_UCG_014_ge e Gastranaerophilales_ge associados ao DHA8. Conclusão: Neste estudo, demonstramos que o padrão estrutural da MI difere significativamente entre os modelos de MASLD e DHA. Estudos são necessários para caracterizar a microbiota e os metabólitos ativos em ambas as condições clínicas, a fim de encontrar novas estratégias terapêuticas.

Thermal Injury Protocol to Study Healing, With and Without Infection, in Guinea Pig (Cavia porcellus) Model / Protocolo de Lesión Térmica, para Estudio de Cicatrización, en Modelo Animal Cobayo (Cavia porcellus)

SUMMARY: Experimental healing studies in humans are complex and difficult to replicate in vitro. Hence, animal models are needed to study the different stages involved. The guinea pig (Cavia porcellus) is a model close to human physiology, including the lack of vitamin C synthesis, a precursor of collagen fibers for healing. The thermal injury in this animal makes it possible to study all the stages of healing, taking few days to show tissue repair in the processes with and without localized infection. The aim of this work was to systematize an experimental guinea pig (Cavia porcellus) animal model protocol for studies on healing with and without localized infection.

Los estudios experimentales de cicatrización en humanos son complejos, difícilmente replicables in vitro, por lo que se hace necesarias modelos animales que permitan el estudio de las distintas etapas que ella implica. El cobayo (Cavia porcellus) resulta ser un modelo cercano a la fisiología humana, incluyendo la falta síntesis de vitamina C precursora de fibras colágenas para la cicatrización. La lesión térmica en este animal, permite estudiar todas las etapas de la cicatrización, mostrando pocos días en la reparación tisular, tanto en proceso con y sin infección localizada. El objetivo de este trabajo fue sistematizar un protocolo de modelo animal experimental en cobayo (Cavia porcellus) para estudios de cicatrización con y sin infección localizada.

Histopathological comparison of bone healing effects of endonasal and percutaneous lateral osteotomy methods in rabbit rhinoplasty model.

INTRODUCTION: Lateral osteotomy is mainly performed either endonasally or percutaneously in rhinoplasty which is a frequently performed operation for the correction of nasal deformities. Both techniques have both advantages and disadvantages relative to each other. OBJECTIVE: The aim of this study was to compare the histopathological effects of endonasal and percutaneous osteotomy techniques performed in rhinoplasty on bone healing and nasal stability in an experimental animal model. METHODS: Eight one year-old New Zealand white rabbits were included. Xylazine hydrocloride and intramuscular ketamine anesthesia were administered to the rabbits. Endonasal osteotomy (8 bones) was performed in Group 1 (n=4), and percutaneous osteotomy (8 bones) in Group 2 (n=4). One month later the rabbits were sacrificed. Bone healing of the rabbits was staged according to the bone healing score of Huddleston et al. In both groups, nasal bone integrity was assessed subjectively. RESULTS: In the percutaneous osteotomy group, Grade 1 bone healing was observed in two samples (25%), Grade 2 bone healing in two samples (25%), Grade 3 bone healing in four samples (50%). In the endonasal osteotomy group, Grade 1 bone healing was observed in 6 samples (75%) and Grade 2 bone healing was observed in 2 samples (25%). In the percutaneous group, fibrous tissue was observed in 2, predominantly fibrous tissue and a lesser amount of cartilage was observed in 2 and an equal amount of fibrous tissue and cartilage was observed in 4 samples. In the endonasal group, fibrous tissue was observed in 6 samples, and predominantly fibrous tissue with a lesser amount of cartilage was observed in 2 samples. In both groups, when manual force was applied to the nasal bones, subjectively the same resistance was observed. CONCLUSION: Percutaneous lateral osteotomy technique was found to result in less bone and periost trauma and better bone healing compared to the endonasal osteotomy technique.

Monoaxial Mechanical Tests on Porcino Knee Ligaments / Ensaios mecânicos monoaxiais nos ligamentos do joelho porcino

Abstract The failure of ligament reconstruction has different risk factors, among which we can highlight the period before its incorporation, which is a mechanically vulnerable period. Loss of resistance over time is a characteristic of living tissues. Dissection with bone insertions of the cruciate ligaments of animal models is not described; however, it is essential for monoaxial assays to extract information from tests such as relaxation. The present work describes the dissection used for the generation of a test body for the performance of nondestructive tests to evaluate the mechanical behavior. We performed dissection of four porcino knee ligaments, proposing a dissection technique for the cruciate ligaments with bone inserts for comparison with collateral ligaments. The ligaments were submitted to relaxation tests and had strain gauges placed during the tests. The results showed viscoelastic behavior, validated by strain gauges and with a loss over time; with some ligaments presenting with losses of up to 20%, a factor to be considered in future studies. The present work dissected the four main ligaments of the knee demonstrating the posterior approach that allows maintaining their bone insertions and described the fixation for the monotonic uniaxial trials, besides being able to extract the viscoelastic behavior of the four ligaments of the knee, within the physiological limits of the knee.

Resumo A falha da reconstrução ligamentar tem diferentes fatores de risco, dentre os quais podemos destacar o período antes da sua incorporação, o qual configura um período mecânico vulnerável. A perda de resistência ao longo do tempo é uma característica dos tecidos vivos. A dissecção com as inserções ósseas dos ligamentos cruzados de modelos animais não é descrita; todavia, para os ensaios monoaxiais, é fundamental extrair as informações de ensaios como os de relaxação. O presente trabalho realiza a descrição da dissecção utilizada para a geração de corpo de prova para a realização de ensaios não destrutivos para avaliar o comportamento mecânico. Realizamos dissecção de quatro ligamentos de joelho porcino, propondo uma técnica de dissecção para os ligamentos cruzados com as inserções ósseas para comparação com os colaterais. Os ligamentos foram submetidos a testes de relaxação e foram colocadas strain gauges durante os testes. Os resultados mostraram comportamento viscoelástico, validado pelas strain gauges e com uma perda ao longo do tempo, sendo que, em alguns ligamentos, as perdas chegaram a até 20%, fator este a ser considerado em trabalhos futuros. O presente trabalho dissecou os quatro principais ligamentos do joelho, demonstrando a abordagem posterior que permite manter as suas inserções ósseas e descrevendo a fixação para os ensaios uniaxiais monotônicos, além de ter conseguido extrair o comportamento viscoelástico dos quatro ligamentos do joelho dentro dos limites fisiológicos do joelho.

Sheep as a large animal model for cochlear implantation / Uso de ovelhas como um modelo animal de grande porte para implante coclear

Abstract Introduction In surgical training, large animal models are more suitable as their anatomy is more similar to humans. In otology, there have been relatively few studies about large animal models for surgical training. Objective In this study, we aimed to do a neuroradiologic evaluation and surgical insertion of a cochlear implant electrode array on a sheep head model. Methods Twenty cadaveric sheep heads were studied. A computed tomography scan and neuroradiologic evaluation was performed on each head, obtaining measurements of the inner ear for each sheep. Sheep measurements were compared to those from temporal bone computed tomography scans from 20 female humans. Surgical procedures were first trained with 13 of the sheep temporal bones, after which cochlear implantation was performed on the remaining 7 temporal bones. The position of the inserted electrode array insertion was confirmed by computed tomography scan after the procedure. Results Neuroradiologic evaluation showed that, relative to the 20 female humans, the mean ratio for sheep was 0.60 for volume of cochlea, 0.70 for height of cochlea, 0.73 for length of cochlea; ratios for other metrics were >0.80. For the surgical training, the round window was found in all 20 sheep temporal bones. Computed tomography scans confirmed that electrode insertions were fully complete; the mean value of electrode array insertion was 18.3 mm. Conclusion The neuroradiologic and surgical training data suggest that the sheep is a realistic animal model to train cochlear implant surgery and collection of perilymph samples, but less so for surgical training of mastoidectomy due to pneumatization of the mastoid.

Resumo Introdução No treinamento cirúrgico, os modelos animais de grande porte são mais adequados, pois sua anatomia é mais semelhante à humana. Em otologia, existem relativamente poucos estudos com modelo animal de grande porte para treinamento cirúrgico. Objetivo Fazer a avaliação neurorradiológica e a inserção cirúrgica de um eletrodo de implante coclear em um modelo de ovelha. Método Vinte cabeças de cadáveres de ovelhas foram estudadas. Foram feitas tomografia computadorizada e avaliação neurorradiológica de cada cabeça, obtiveram‐se medidas da orelha interna de cada ovelha. As medidas das ovelhas foram comparadas às de tomografias computadorizadas do osso temporal de 20 mulheres. Os procedimentos cirúrgicos foram inicialmente treinados com 13 dos ossos temporais de ovelhas, após o qual o implante coclear foi feito nos 7 ossos temporais restantes. A posição de inserção do arranjo de eletrodos foi confirmada por tomografia computadorizada após o procedimento. Resultados A avaliação neurorradiológica mostrou que, em comparação às 20 mulheres, a proporção média para as ovelhas foi de 0,60 para o volume da cóclea, 0,70 para a altura da cóclea, 0,73 para o comprimento da cóclea; as proporções para as outras medidas foram > 0,80. Em relação ao treinamento cirúrgico, a janela redonda foi encontrada em todos os 20 ossos temporais de ovelhas. A tomografia computadorizada confirmou que as inserções dos eletrodos foram totalmente completas; o valor médio da inserção do arranjo de eletrodos foi de 18,3 mm. Conclusão Os dados do treinamento neurorradiológico e cirúrgico sugerem que a ovelha é um modelo animal realista para o treinamento da cirurgia de implante coclear e coleta de amostras da perilinfa, mas não tão realista para o treinamento cirúrgico de mastoidectomia devido à pneumatização da mastoide.

Healing of Wounds Treated with Chitosan Hydrogels with Extracts from Aloe vera and Calendula officinalis / Cicatrización de Heridas Tratadas con Hidrogeles de Quitosano con Extractos de Aloe vera y Calendula officinalis

ABSTRACT This project's purpose was to evaluate the healing effects of chitosan (CS) hydrogels loaded with extracts from Aloe vera (CS+AV) and Calendula officinalis (CS+CO) on wounds of diabetic and non-diabetic Wistar rats. A total of 24 rats were used; animals were randomly divided into three diabetic and three non-diabetic groups (one control and two treated groups) and monitored for 13 days. A biopsy on the wound site was recovered to assess the collagen and n-acetyl glucosamine content. The wound area ratio was reduced since day 1 on both non-diabetic treated groups. A similar effect was observed on the diabetic group treated with CS+AV, while the diabetic group treated with CS+CO showed a reduction in wound area compared to the diabetic control until day 11 after being wounded. Collagen and n-acetyl glucosamine content were higher in every treated group. Further studies are needed to clarify the underlying mechanisms through which they promote wound healing. These results suggest that the hydrogels prepared are potential material to be used as wound dressings.

RESUMEN El propósito de este proyecto fue evaluar los efectos curativos de los hidrogeles de quitosano con extractos de Aloe vera (CS + AV) y Calendula officinalis (CS + CO) en heridas en ratas Wistar diabéticas y no diabéticas. Se utilizaron un total de 24 ratas; los animales fueron divididos aleatoriamente en tres grupos diabéticos y tres no diabéticos (un grupo control y dos tratados) y se monitorearon durante 13 días. Se recuperó una biopsia del sitio de la herida para evaluar el contenido de colágeno y n-acetilglucosamina. El área de la herida se redujo desde el día 1 en ambos grupos no diabéticos tratados. Se observó un efecto similar en el grupo diabético tratado con CS + AV, mientras que el grupo diabético tratado con CS + CO mostró una reducción del área de la herida en comparación al control diabético hasta el día 11 después de la creación de la herida. El contenido de colágeno y n-acetilglucosamina fue mayor en todos los grupos tratados. Se necesitan más estudios para aclarar los mecanismos subyacentes a través de los cuales estos tratamientos promueven la cicatrización de heridas. Estos resultados sugieren que los hidrogeles preparados son materiales con potencial para usarse como apósitos para heridas.

Modelo preclínico de obesidad basado en alimentos altamente procesados y de alta palatabilidad / Preclinical model of obesity based on ultra-processed and highly palatable foods

Resumen Introducción: el alarmante incremento de la obesidad en todo el mundo y en Costa Rica responde principalmente a modificaciones en la composición de la dieta habitual de las personas. La presente investigación tuvo como objetivo implementar un protocolo de alimentación formulado a partir de alimentos altamente procesados y de alta palatabilidad (APAP) consumidos por la población costarricense para, luego, evaluar sus efectos en la conducta alimentaria y en parámetros biométricos y bioquímicos. Metodología: ratas adultas macho Wistar se asignaron a dos grupos. Al primero se le administró alimento estándar para roedores (grupo DC) y al segundo, alimentos APAP (grupo APAP), durante ocho semanas. Resultados: a lo largo de ese periodo, los animales expuestos a los APAP exhibieron mayor ingesta y energía, caracterizadas por un alto consumo de grasas y uno menor de proteínas y fibra; además, mostraron un incremento significativo en los diversos parámetros de obesidad (e. g., peso corporal y ganancia de peso, índice de Lee y adiposidad central) y niveles descriptivamente superiores de glucosa y triglicéridos en sangre, pero notablemente menores de colesterol total. Conclusiones: los resultados indican que una dieta basada en los alimentos APAP más frecuentes en la población costarricense es capaz de inducir hiperfagia y obesidad. Así, este modelo constituye una herramienta prometedora para ahondar en el estudio de las factores neurobiológicos y metabólicos relacionados con la obesidad por el sobreconsumo de alimentos APAP.

Abstract Introduction. The alarming increase in obesity both worldwide and in Costa Rica is mainly due to changes in the composition of the usual diet of the population. The goal of our research was to implement a feeding protocol formulated from ultra-processed and highly palatable foods (UPHP) consumed by the Costa Rican population and to evaluate the effects of the UPHP diet on eating behavior and biometric and biochemical parameters. Methods: Adult male Wistar rats were assigned to two groups. One group was given standard rodent chow (DC group) while the other group received UPHP foods (UPHP group) for eight weeks. Results: Throughout this period, animals exposed to the UPHP diet exhibited higher food and energy intake characterized by high consumption of fat and lower consumption of protein and fiber. Animals in the UPHP group also showed a significant increase in obesity parameters (e.g., body weight and bodyweight gain, Lees index, and central adiposity). Furthermore, the UPHP group had descriptively higher levels of blood glucose and triglycerides and significantly lower levels of total cholesterol. Conclusions: Our results indicate that a feeding protocol based on the most frequent food choices of the Costa Rican population is capable of inducing hyperphagia and obesity. This model constitutes a promising tool to delve into the study of the neurobiological and metabolic factors related to obesity induced by overconsumption of UPHP foods.

Ambystoma mexicanum, A MODEL ORGANISM IN DEVELOPMENTAL BIOLOGY AND REGENERATION: A COLOMBIAN EXPERIENCE / Ambystoma mexicanum, un organismo modelo en biología del desarrollo y regeneración: experiencia colombiana

ABSTRACT Ambystoma mexicanum is a urodele amphibian endemic to Xochimilco Lake in Mexico, it belongs to the salamander family Ambystomatidae. This species has frequently been used as model organism in developmental biology and regeneration laboratories around the world due to its broad regenerative capacities and adaptability to laboratory conditions. In this review we describe the establishment of the first colony of axolotls in Colombia to study tissue regeneration and our perspectives on the use A. mexicanum as a model organism in Colombia are discussed emphasizing its possible uses in regeneration and developmental biology.

RESUMEN Ambystoma mexicanum es un anfibio urodelo endémico del lago Xochimilco en México, perteneciente a la familia de salamandras Ambystomatidae. Esta especie se ha empleado frecuentemente como organismo modelo en laboratorios de biología del desarrollo y regeneración alrededor del mundo, dadas sus amplias capacidades regenerativas y adaptabilidad en condiciones de laboratorio. En esta revisión, se describe el establecimiento de la primera colonia de ajolotes en Colombia, para adelantar estudios de regeneración de tejidos, y se discuten las perspectivas de A. mexicanum como organismo modelo en el país, enfatizando sus posibles usos en regeneración y biología del desarrollo.

Chemopreventive agents on a mouse skin carcinogenesis model: an integrative review / Agentes quimiopreventivos em um modelo de carcinogênese de pele em camundongos: uma revisão integrativa / Agentes quimiopreventivos en un modelo de carcinogénesis cutánea en ratón: una revisión integradora

Squamous cell carcinoma (SCC) is a non-melanoma skin cancer, with chronic sun exposure as the main risk factor. Excisional surgery is the most indicated treatment; however, patients can suffer functional, aesthetic, and psychological damage depending on the lesion site. Topical administration of 7,12-dimethylbenz[a]anthracene (DMBA) and 12-O-Tetradecanoylphorbol-13- acetate (TPA) induce to the appearance of benign skin tumors in mice, some of which develop into SCC. This protocol has been used to analyze the effects of many chemopreventive agents that may block or inhibit the mechanisms of action of chemical carcinogenesis. We compared the effects of chemopreventive agents in an induced skin carcinogenesis animal model. In the Scopus, PubMed, and EMBASE databases, we searched for manuscripts published between June 16, 2011, and June 16, 2021. We excluded studies conducted in vitro or on transgenic mice; in addition, studies without drug dosage, route of administration, or tumor incidence were excluded. We selected 26 studies and analyzed their main characteristics and the outcomes of tumorigenesis analysis. Most chemopreventive agents have shown excellent potential to inhibit the development of skin tumors. This review also discusses the standardization of studies in animal models to ensure better responses and future randomized clinical trials for cancer treatment and prevention.

O carcinoma espinocelular cutâneo (CEC) é um câncer de pele não melanoma, com a exposição solar crônica como o principal fator de risco. A cirurgia excisional é o tratamento mais indicado; entretanto, os pacientes podem sofrer danos funcionais, estéticos e psicológicos dependendo do local da lesão. A administração tópica de 7,12-dimetilbenz[a]antraceno (DMBA) e 12-O- Tetradecanoilforbol-13-acetato (TPA) induz ao aparecimento de tumores cutâneos benignos em camundongos, alguns dos quais evoluíram para CEC. Este protocolo tem sido utilizado para analisar os efeitos de muitos agentes quimiopreventivos que podem bloquear ou inibir os mecanismos de ação da carcinogênese química. Comparamos os efeitos de agentes quimiopreventivos em um modelo animal que foi induzido à carcinogênese de pele. Nas bases de dados Scopus, PubMed e EMBASE, buscamos manuscritos publicados entre 16 de junho de 2011 e 16 de junho de 2021. Excluímos estudos realizados in vitro ou em camundongos transgênicos; além disso, estudos sem dosagem de drogas, via de administração ou incidência de tumores foram excluídos. Selecionamos 26 estudos e analisamos suas principais características e os resultados da análise da tumorigênese. A maioria dos agentes quimiopreventivos tem demonstrado excelente potencial para inibir o desenvolvimento de tumores cutâneos. Esta revisão também discute a padronização de estudos em modelos animais para garantir melhores respostas e futuros ensaios clínicos randomizados para tratamento e prevenção do câncer.

El carcinoma de células escamosas (CCE) es un cáncer de piel no melanoma, cuyo principal factor de riesgo es la exposición crónica al sol. La cirugía de escisión es el tratamiento más indicado; sin embargo, los pacientes pueden sufrir daños funcionales, estéticos y psicológicos dependiendo de la localización de la lesión. La administración tópica de 7,12-dimetilbenz[a]antraceno (DMBA) y 12-O-Tetradecanoilforbol-13-acetato (TPA) inducen a la aparición de tumores cutáneos benignos en ratones, algunos de los cuales se convierten en CCE. Este protocolo se ha utilizado para analizar los efectos de muchos agentes quimiopreventivos que pueden bloquear o inhibir los mecanismos de acción de la carcinogénesis química. Comparamos los efectos de los agentes quimiopreventivos en un modelo animal de carcinogénesis cutánea inducida. En las bases de datos Scopus, PubMed y EMBASE, se buscaron los manuscritos publicados entre el 16 de junio de 2011 y el 16 de junio de 2021. Se excluyeron los estudios realizados in vitro o en ratones transgénicos; además, se excluyeron los estudios sin dosis de fármacos, vía de administración o incidencia tumoral. Se seleccionaron 26 estudios y se analizaron sus características principales y los resultados del análisis de la tumorigénesis. La mayoría de los agentes quimiopreventivos han mostrado un excelente potencial para inhibir el desarrollo de tumores cutáneos. Esta revisión también analiza la estandarización de los estudios en modelos animales para garantizar mejores respuestas y futuros ensayos clínicos aleatorios para el tratamiento y la prevención del cáncer.

Características morfométricas de la mandíbula de rata: un estudio radiológico de un modelo experimental animal ampliamente utilizado a través de CBCT / Morphometric characteristics of rat mandibular bone: radiologic study of a widely used animal as experimental model through CBCT

La mandíbula de rata es una de las estructuras anatómicas de mayor interés en la investigación en las ciencias odontológicas, esto debido a su similitud con la mandíbula humana. El objetivo de este estudio fue caracterizar morfometricamente la mandíbula de ratas mediante CBCT. Se analizó el examen cone beam de 20 ratas hembras, adultas sanas. Mediante el software del examen, fue posible aislar la mandíbula derecha e izquierda de las otras estructuras y realizar adecuadamente las medidas morfométricas de interés. En la comparación de ambos lados, sólo dos medidas presentaron diferencias significativas. La distancia entre el punto más profundo de la escotadura sigmoidea hasta el punto más profundo de la escotadura en el margen inferior de la mandíbula, fue mayor en el lado izquierdo que en el derecho. Y la distancia entre el punto más superior del cóndilo hasta la base mandibular, en la proyección perpendicular del plano mandibular fue mayor en el lado izquierdo que en el derecho. De acuerdo a las medidas obtenidas, podemos determinar que la mandíbula de la rata es una estructura alargada, con dimensiones mayores en sentido anteroposterior en comparación con las medidas verticales. El conocimiento de la anatomía de la mandíbula de rata y sus variaciones por lado permite a los investigado- res tener referencias adecuadas para los estudios que involucren esta estructura, como por ejemplo, investigaciones que requieran la aplicación de técnicas anestésicas, estudio del dolor orofacial, estudio patofisiológico de la ATM, estudio del crecimiento óseo, testeo de biomateriales dentales o en el estudio de procesos fisiopatológicos relacionados con los tejidos dentales o periodontales. La mandíbula de la rata es un buen modelo animal debido a su reproducibilidad y bajo costo. La mandíbula derecha e izquierda son similares en sus dimensiones anteroposteriores, pero no las verticales.

SUMMARY: The rat jaw is one of the most interesting anatomical structures in dental science research, due to its similarity to the human jaw. The aim of this study was to morphometrically characterize the mandible of rats by CBCT. The cone beam examination of 20 healthy adult female rats was analyzed. Using the examination software, it was possible to isolate the right and left mandible from the other structures and adequately perform the morphometric measurements of interest. In the comparison of both sides, only two measures presented significant differences. The distance from the deepest point of the sigmoid notch to the deepest point of the notch at the lower margin of the mandible was greater on the left side than on the right. And the distance between the most superior point of the condyle to the mandibular base, in the perpendicular projection of the mandibular plane, was greater on the left side than on the right. According to the measurements obtained, we can determine that the rat jaw is an elongated structure, with larger dimensions in the anteroposterior direction compared to the vertical measurements. Knowledge of the anatomy of the rat mandible and its variations per side allows researchers to have adequate references for studies involving this structure, such as research that requires the application of anesthetic techniques, study of orofacial pain, pathophysiological study of the TMJ, study of bone growth, testing of dental biomaterials or in the study of pathophysiological processes related to den- tal or periodontal tissues. The rat mandible is a good animal model due to its reproducibility and low cost. The right and left mandible are similar in their anteroposterior dimensions, but not the vertical ones.

Effects of laser photobiomodulation on tgf-ß and vegf expression in burn wound: systematic review and meta-analysis in the animal model / Influencia de la fotobiomodulación por láser en la expresión de tgf-ß y vegf en heridas por quemadura: revisión sistemática y meta-análisis en modelo animal

SUMMARY: Laser photobiomodulation (laser PBM) is known to be able to accelerate burn wound healing in the animal model; however little evidence exists on the action of laser PBM on the expression of important proteins in wound healing in the animal model, such as VEGF and TGF-ß1. The aim of this study was to carry out a systematic review in order to analyse the effect of laser PBM on VEGF and TGF-ß expression during burn wound repair in the animal model. A systematic review was carried out of the EMBASE, PubMed/ MEDLINE and LILACS databases. The studies included were preclinical studies that analysed the action of laser PBM on the expression of VEGF and TGF-ß (1, 2, 3) during burn wound repair in the animal model. The SYRCLE risk of bias tool was used. Random effect models were used to estimate the combined effect. Increased VEGF expression was observed with the use of laser PBM at 4.93 J/cm2 per point in the first two weeks after induction of the burn wound, with greater size of effect in the second week (SDM = 5.72; 95% CI: 3.14 to 8.31, I2 = 0 %; very low certainty of evidence). We also observed that the effect of laser PBM on TGF-ß1 expression was greater than in the control in the first week (SDM = -0.45; 95% CI: -1.91 to 1.02, I2 = 51 %; very low certainty of evidence), but diminished in the third week after induction of the lesion (SDM = -2.50; 95% CI: 3.98 to -1.01, I2 = 0 %; very low certainty of evidence). Laser PBM has an effect on TGF-ß1 and VEGF expression, promoting burn wound repair in the animal model.

RESUMEN: Es sabido que la fotobiomodulación por láser (FBM láser) puede acelerar el proceso de curación de heridas por quemadura en modelo animal, sin embargo aún se carece de mayor evidencia sobre la acción de la FBM láser en la expresión de proteínas importantes en el proceso de curación de heridas en modelo animal, como VEGF y TGF-ß1. Así, el objetivo de este estudio fue realizar una revisión sistemática a fin de analizar el efecto de la FBM láser sobre la expresión de VEGF, TGF-ß durante el proceso de reparación de heridas por quemadura en modelo animal. Se realizó una búsqueda sistemática en las bases de datos EMBASE, PubMed/MEDLINE y LILACS. Se incluyeron estudios preclínicos que analizaron la acción de la FBM láser en la expresión de VEGF, TGF-ß (1, 2, 3) durante el proceso de reparación de heridas por quemadura en modelo animal. Se utilizó la herramienta de riesgo de sesgo SYRCLE. Se utilizaron modelos de efectos aleatorios para estimar el efecto combinado. Observamos aumento de la expresión de VEGF con el uso de FBM láser 4.93 J/cm2 por punto, en las dos primeras semanas tras inducción de la herida por quemadura, con mayor tamaño de efecto en la segunda semana (SDM = 5,72; IC del 95%: 3,14 a 8,31, I2 = 0 %; certeza de la evidencia muy baja). También se observó el efecto de la FBM láser en la expresión del TGF- ß1 que fue mayor que el control en la primera semana (SDM = - 0,45; IC del 95%: -1,91 a 1,02, I2 = 51 %; certeza de la evidencia muy baja), disminuyendo en la tercera semana tras inducción de la lesión (SDM = -2,50; IC del 95%: -3,98 a -1,01; I2 = 0 %; certeza de la evidencia baja). La TFB por láser ejerce influencia en la expresión de TGF-ß1 y VEGF favoreciendo el proceso de reparación de heridas por quemadura en modelo animal.

Vitamin E suppresses aortic ultrastructural alterations induced by toxic doses of monosodium glutamate / La vitamina E suprime las alteraciones ultraestructurales aórticas inducidas por dosis tóxicas de glutamato monosódico

SUMMARY: An association between certain food additives and chronic diseases is reported. Current study determined whether administering toxic doses of the food additive monosodium glutamate (MSG) into rats can induce aortopathy in association with the oxidative stress and inflammatory biomarkers upregulation and whether the effects of MSG overdose can be inhibited by vitamin E. MSG at a dose of (4 mg/kg; orally) that exceeds the average human daily consumption by 1000x was administered daily for 7 days to the rats in the model group. Whereas, rats treated with vitamin E were divided into two groups and given daily doses of MSG plus 100 mg/ kg vitamin E or MSG plus 300 mg/kg vitamin E. On the eighth day, all rats were culled. Using light and electron microscopy examinations, a profound aortic injury in the model group was observed demonstrated by damaged endothelial layer, degenerated smooth muscle cells (SMC) with vacuoles and condensed nuclei, vacuolated cytoplasm, disrupted plasma membrane, interrupted internal elastic lamina, clumped chromatin, and damaged actin and myosin filaments. Vitamin E significantly protected aorta tissue and cells as well as inhibited MSG-induced tissue malondialdehyde (MDA), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). The highest used vitamin E dosage was more effective. Additionally, a significant correlation was observed between the aortic injury degree and tissue MDA, TNF-α, IL-6, and superoxide dismutase (SOD) levels (p=0.001). Vitamin E effectively protects against aortopathy induced by toxic doses of MSG in rats and inhibits oxidative stress and inflammation.

RESUMEN: Se reporta una asociación entre ciertos aditivos alimentarios y enfermedades crónicas. El objetivo de este estudio fue determinar si la administración de dosis tóxicas del aditivo alimentario glutamato monosódico (MSG) en ratas puede inducir aortopatía en asociación con el estrés oxidativo y la regulación positiva de los biomarcadores inflamatorios y si el efecto de una sobredosis de MSG se puede inhibir con vitamina E. Se administró MSG diariamente durante 7 días una dosis de (4 g/kg; por vía oral) que excede el consumo diario humano promedio, en 1000x a las ratas del grupo modelo. Mientras que las ratas tratadas con vitamina E se dividieron en dos grupos y se administraron dosis diarias de MSG más 100 mg/kg de vitamina E o MSG más 300 mg/kg de vitamina E. Todas las ratas fueron sacrificadas en el octavo día. Usando exámenes de microscopía óptica y electrónica, se observó una lesión aórtica profunda en el grupo modelo demostrada por una capa endotelial dañada, células musculares lisas degeneradas (SMC) con vacuolas y núcleos condensados, citoplasma vacuolado, membrana plasmática rota, lámina elástica interna interrumpida, cromatina agrupada y filamentos de actina y miosina dañados. La vitamina E protegió significativamente el tejido y las células de la aorta, además de inhibir el malondialdehído tisular (MDA) inducido por MSG, la interleucina-6 (IL-6) y el factor de necrosis tumoral alfa (TNF-α). La dosis más alta de vitamina E utilizada fue más efectiva. Además, se observó una correlación significativa entre el grado de lesión aórtica y los niveles tisulares de MDA, TNF-α, IL-6 y superóxido dismutasa (SOD) (p=0,001). La vitamina E efectivamente protege contra la aortopatía inducida por dosis tóxicas de MSG en ratas e inhibe el estrés oxidativo y la inflamación.