The proteolytic fraction from Vasconcellea cundinamarcensis accelerates wound healing after corneal chemical burn in rabbits.

INTRODUCTION: Chemical ocular burns are among the most frequently eye-related injuries, which require immediate and intensive evaluation and care since they may lead to potential complications such as superinfection, corneal perforation, and blindness.Vasconcellea cundinamarcensis, a species from Caricaceae family, contains highly active proteolytic enzymes in its latex that show healing activity in animal models bearing lesions of different etiologies. METHODS: We evaluate the ocular toxicity of the proteolytic fraction from V. cundinamarcensis (P1G10) by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and Hen's Egg Test-Chorioallantoic Membrane test. The corneal healing property of P1G10 was studied by the ethanol-chemical burn in the rabbit's eyes. RESULTS: P1G10 is safe for ocular administration, except when administrated at 10µg/mL. P1G10 at 1µg/mL accelerates the corneal re-epithelization achieving complete wound closure after 72h of chemical burn. Also, P1G10 modulated the inflammatory response and controlled the arrangement of collagen fibers in the stroma, demonstrating its potential corneal healing properties. CONCLUSIONS: Our work was the first one to evaluate the ophthalmic application of P1G10. Here we demonstrated that P1G10 is suitable for ocular administration and it has a promising corneal healing activity which may emerge as a new pharmacological tool to the development of a new drug for ocular surface chemical injuries in the future.

Treatment for chemical burning using liquid crystalline nanoparticles as an ophthalmic delivery system for pirfenidone.

Some recent studies have shown that pirfenidone (PFD) has favorable results in the healing process of the cornea. However, PFD in solution exhibits short half-life after topical application, and in this context, a liquid crystal nanoparticle system containing PFD (PFD-LCNPs) was developed. The nanoparticles were characterized by transmission electron microscopy, atomic force microscopy, small angle X-ray diffraction and polarized light microscopy. The PFD-LCNPs had particle size and zeta potential of 247.3 nm and -33.60 mV (stores at 4 °C), respectively, and 257.5 nm and -46.00 mV (stored at 25 °C), respectively. The pH of the formulation was 6.9 and the encapsulation efficiency was 35.9%. The in vitro release profiles indicated that PFD sustained release from PFD-LCNPs for up to 12 h. In vitro study of ocular irritation (HET-CAM test) concluded that components of the formulation are well tolerated for ocular administration. Corneal re-epithelialization time after chemical burning was significantly reduced in rabbits treated with PFD-loaded LCNPs when compared to the group treated with a vehicle. In addition, the anti-inflammatory action of pirfenidone was observed by reducing myeloperoxidase activity (MPO) and inflammatory cells in the histology of the tissues of animals treated with PFD-LCNPs. These findings indicated that the PFD-LCNPs might have the potential for effective ocular drug delivery.

Anti-Inflammatory and Anti-Fibrotic Effects of Human Amniotic Membrane Mesenchymal Stem Cells and Their Potential in Corneal Repair.

Acute ocular chemical burns are ophthalmic emergencies requiring immediate diagnosis and treatment as they may lead to permanent impairment of vision. The clinical manifestations of such burns are produced by exacerbated innate immune response via the infiltration of inflammatory cells and activation of stromal fibroblasts. New therapies are emerging that are dedicated to repair mechanisms that improve the ocular surface after damage; for example, transplantation of stem cells (SC) has been successfully reported for this purpose. The pursuit of easily accessible, noninvasive procedures to obtain SC has led researchers to focus on human tissues such as amniotic membrane. Human amniotic mesenchymal SC (hAM-MSC) inhibits proinflammatory and fibrotic processes in different diseases. hAM-MSC expresses low levels of classical MHC-I and they do not express MHC-II, making them suitable for regenerative medicine. The aim of this study was to evaluate the effect of intracameral injection of hAM-MSC on the clinical manifestations, the infiltration of inflammatory cells, and the activation of stromal fibroblasts in a corneal alkali-burn model. We also determined the in vitro effect of hAM-MSC conditioned medium (CM) on α-SMA+ human limbal myofibroblast (HLM) frequency and on release of neutrophil extracellular traps (NETs). Our results show that intracameral hAM-MSC injection reduces neovascularization, opacity, stromal inflammatory cell infiltrate, and stromal α-SMA+ cells in our model. Moreover, in in vitro assays, CM from hAM-MSC decreased the quantity of α-SMA+ HLM and the release of NETs. These results suggest that intracameral hAM-MSC injection induces an anti-inflammatory and anti-fibrotic environment that promotes corneal wound healing. Stem Cells Translational Medicine 2018;7:906-917.

[Ingestion of caustic substances in children: 3 years of experience]. / Ingesta de cáusticos en niños, experiencia de 3 años.

INTRODUCTION: There is no clear consensus on the management of accidental ingestion of caustic substances in paediatrics. The aim of this study was to determine the profile of the paediatric population treated due to caustic ingestion in a Healthcare Centre. PATIENTS AND METHOD: A descriptive study was conducted on patients treated for the ingestion of caustic substances in our hospital during the period 2008-2011. RESULTS: A total of 12 patients were treated, with a mean age of 3.8 years (1-13 years), with the majority males (58.8%). An alkaline product was ingested by 58.3%, and an acid by 41.6%. The majority (58.3%) did not refer to symptoms and the remainder referred to vomiting (33.3%), odynophagia (16.6%), haematemesis (8.3%), hyper-salivation (8.3%) and shortness of breath (8.3%). Oral cavity lesions were observed in 75% of cases. All, except one, were accidental. An endoscopy was performed on all of them (100%) between 12 and 24hours post-ingestion, with pathological findings in 41.6%. In the group that ingested an alkali, 2 (16.6%) patients had lesions, one a grade 2B and one a grade 3 oesophagitis. In the acid ingestion group, 4 (33.3%) patients had lesions; one grade 1-2A oesophagitis, two acute non-erosive gastritis, and one acute haemorrhagic gastritis. A follow-up endoscopy was performed depending on the previous endoscopic findings. Only two patients presented with complications. CONCLUSIONS: Emphasis is placed on the endoscopic evaluation in the first 24hours of deliberate asymptomatic ingestions, as well as a strict follow-up in those that ingested acids, due to delayed associated lesions.

Ingesta de cáusticos en niños, experiencia de 3 años / Ingestion of caustic substances in children: 3 years of experience

Introdución: La ingesta accidental de cáusticos en pediatría no dispone de un consenso claro de actuación. El objetivo de este estudio fue caracterizar la población pediátrica atendida por ingesta de cáusticos en un centro asistencial. Pacientes y método: Estudio descriptivo de los pacientes atendidos en nuestro hospital por la ingesta de cáusticos durante el período 2008-2011. Resultados: Se atendieron 12 pacientes, edad media de 3,8 años (1-13 años). Predominio de varones (58,8%). Un 58,3% ingirió producto alcalino y un 41,6% ácido. El 58,3% no refería sintomatología, el resto refirió vómitos (33,3%), odinofagia (16,6%), hematemesis (8,3%), sialorrea (8,3%) y dificultad respiratoria (8,3%). El 75% presentaron lesiones en la cavidad oral. Todos, salvo un caso, fueron accidentales. Se realizó endoscopia al 100% entre las 12 y 24 h postingesta con hallazgos patológicos en un 41,6%. En el grupo ingesta de álcalis 2 pacientes presentaron lesiones (16,6%): una esofagitis grado 2B y una grado 3. En el grupo ingesta de ácidos 4 pacientes (33,3%) presentaron lesiones: una esofagitis aguda grado 1-2A, 2 gastritis agudas no erosivas y una gastritis aguda hemorrágica. Se realizó endoscopia de control según los hallazgos endoscópicos previos. Solo 2 presentaron complicaciones posteriores. Conclusiones: Destacamos la valoración endoscópica en las primeras 24 h en todas las ingestas sintomáticas y deliberadas, así como la reevaluación estrecha en las ingestas ácidas, por asociar lesiones diferidas.

Introduction: There is no clear consensus on the management of accidental ingestion of caustic substances in paediatrics. The aim of this study was to determine the profile of the paediatric population treated due to caustic ingestion in a Healthcare Centre. Patients and method: A descriptive study was conducted on patients treated for the ingestion of caustic substances in our hospital during the period 2008-2011. Results: A total of 12 patients were treated, with a mean age of 3.8 years (1-13 years), with the majority males (58.8%). An alkaline product was ingested by 58.3%, and an acid by 41.6%. The majority (58.3%) did not refer to symptoms and the remainder referred to vomiting (33.3%), odynophagia (16.6%), haematemesis (8.3%), hyper-salivation (8.3%) and shortness of breath (8.3%). Oral cavity lesions were observed in 75% of cases. All, except one, were accidental. An endoscopy was performed on all of them (100%) between 12 and 24 hours post-ingestion, with pathological findings in 41.6%. In the group that ingested an alkali, 2 (16.6%) patients had lesions, one a grade 2B and one a grade 3 oesophagitis. In the acid ingestion group, 4 (33.3%) patients had lesions; one grade 1-2A oesophagitis, two acute non-erosive gastritis, and one acute haemorrhagic gastritis. A follow-up endoscopy was performed depending on the previous endoscopic findings. Only two patients presented with complications. Conclusions: Emphasis is placed on the endoscopic evaluation in the first 24 hours of deliberate asymptomatic ingestions, as well as a strict follow-up in those that ingested acids, due to delayed associated lesions.

Transglutaminase binding fusion protein linked to SLPI reduced corneal inflammation and neovascularization.

BACKGROUND: To study the effect of topical administration of a fusion protein (PF-MC) made up of N-terminal portion of the protease inhibitor Trappin-2 (which is a substrate of transglutaminasa-2) and SLPI (protein with anti-inflammatory, anti-bacterial and anti-viral ability), in an animal model of corneal inflammation and angiogenesis. METHODS: An alkali injury was produced with a filter paper of 3 mm with 1 N NaOH during 40 seconds on the right cornea of 36 male Sprague Dawley rats, under general anesthesia. Animals were divided into three groups according to treatment. Group 1 was treated with 10 ul of PF-MC (200 ug/ml; n = 12), Group 2, with 10 ul of SLPI (200 ug/ml; n = 12) and Group 3 was treated with buffer (10 ul; n = 12) topically administered four times a day for up to 7 days. Half of the animals were sacrificed at day 3 before making a re-epithelialization time analysis with fluorescein staining at 18 and 24 hours. In the remaining animals corneal opacity was studied and digital photographs were taken at day 7 before doing euthanasia. Eyes were processed for histology and immunofluorescence. RESULTS: Corneal ulcerated area was significantly lower in PF-MC treated animals compared to SLPI and buffer-treated animals at 18 hours and 24 hours postinjury. A clear cornea and fundus red reflex was only found among PF-MC treated animals. Histological analysis revealed a stratified corneal epithelium with at least three layers in all PF-MC animals at day 7. In this group there was a reduced number of PMNs in the corneal stroma at 3 and 7 days of follow-up. Besides, corneal neovascularization was much more extended in SLPI and Buffer animals than in animals treated with PF-MC. CONCLUSIONS: The binding of SLPI with Cementoin to transglutaminase seems to be an effective strategy to treat corneal inflammation and angiogenesis.

Perfil sociodemográfico e etiológico de pacientes internados em um centro de referência para tratamento de queimados em Mato Grosso do Sul / Demographic and etiologic profiles of patients hospitalized in a reference center for burn treatment in Mato Grosso do Sul

INTRODUÇÃO: O presente estudo abordou a questão da hospitalização de 13 pacientes, crianças e adolescentes, enfocando especificamente o paciente queimado internado em um Centro de Tratamento de Queimaduras. O objetivo foi o de observar e analisar a percepção dos envolvidos no processo de tratamento, para compreender a relação desse paciente com a dor, com o processo de tratamento, com a qualidade de vida no ambiente hospitalar e com sua autoimagem. Levantar informações que revelem a importância de um trabalho profilático do trauma térmico. MÉTODO: Para atender os objetivos da pesquisa, foi utilizado o método de investigação de Estudo de Caso com abordagem qualitativa. RESULTADOS: Os resultados apontaram uma maioria dos pacientes do sexo masculino. O agente etiológico predominante foi o etanol. Os acidentes causaram queimaduras de gravidades diversas, sendo 1 de 1º e 2º graus, 7 de 2º e 3º graus e 5 de 3º grau. O tempo de internação variou de 15 a 75 dias. As idades dos pacientes variaram entre 1 ano e oito meses a 18 anos. Quanto à escolarização, com exceção do paciente mais novo, todos frequentavam a rede de ensino. Quanto ao nível socioeconômico, a maioria tem uma renda familiar de até dois salários mínimos, que não são suficientes. De modo geral, encontra-se apenas uma pessoa trabalhando, por família. CONCLUSÕES: Os resultados pesquisados demonstram a necessidade de orientação aos pais, com programas educativos e campanhas de prevenção.

INTRODUCTION: The present study addressed the issue of hospitalization in 13 patients, children and adolescents, specifically focusing on burn patients admitted to a center for burn treatment. The objective of this study was to observe and analyze the perception of those involved in the treatment process in order to understand the relationship of the patient with pain and the treatment process with the quality of life in the hospital environment and with their self-image, and to collect information on the importance of prophylactic treatment on thermal trauma. METHODS: To meet the objectives of the research, we used the case study method with a qualitative approach. RESULTS: The results showed that most of the patients were male. The predominant etiologic agent was ethanol. The accidents caused burns of various severities, first- and second-degree burns in 1 patient, second- and third-degree burns in 7 patients, and third-degree burns in 5 patients. The length of hospitalization ranged from 15 to 75 days. The ages of the patients ranged from 1 year 8 months to 18 years. As to education, with the exception of the youngest patient, all attended the school network. Regarding socioeconomic level, most had a family income of up to 2 minimum wages, which was not sufficient. In general, only one person worked per family. CONCLUSIONS: The results demonstrate the need to provide guidance to parents, with educational programs and campaigns.

Seventy per cent hydrofluoric acid burns: delayed decontamination with hexafluorine® and treatment with calcium gluconate.

This is a case report of decontamination and treatment of a 70% hydrofluoric acid (HF) dermal splash injury. A worker was splashed with 70% HF, sustaining approximately 10% TBSA first- to third-degree chemical skin burns of the face, trunk, and left thigh and leg. Initial decontamination involved water rinsing, removal of contaminated clothing, more water rinsing, topical application of magnesium oxide, and administration of intravenous narcotics for management of severe pain. After a delay of approximately 3 hours, active skin washing with Hexafluorine®, 5 L, was performed, followed by intravenous, intradermal perilesional, and topical inunction administration of calcium gluconate. Pain relief and a cooling sensation were quite prompt after Hexafluorine® decontamination. Surgical debridement and skin grafting of the more severe burns were required. No significant systemic toxicity developed, although this has occurred in previously reported similar concentrated HF dermal splash exposure cases, some of which resulted in fatality. While burns did develop, the patient was released from the intensive care service after 2 days and, after skin grafting, had a good outcome at 90-day follow-up. Even after a long delay, decontamination with Hexafluorine® appeared to be beneficial in this case.

[Effect of subconjunctival bevacizumab on corneal neovascularization and reepithelization 25 days after chemical burn]. / Ação do bevacizumabe subconjuntival na neovascularização e re-epitelização corneana 25 dias após queimadura química.

PURPOSES: To evaluate the effect of subconjunctival bevacizumab in an experimental model of neovascularization in rabbit cornea. Determine its effect on vessels extension, inflammation, epithelialization of the cornea and whether the evaluation method used is appropriate to compare neovascular models. METHODS: Experimental, prospective, randomized, blinded study in twenty rabbits subjected to chemical trauma with sodium hydroxide at 1N divided into two groups. The study group received subconjunctival injection of 0.15 ml (3.75 mg) of bevacizumab and was compared with the control group that received subconjunctival injection of 0.15 ml saline solution. After 25 days, digital photographic analysis was performed to assess the vessel's extension and inflammation/diameter according to pre-established criteria. Histopathology of the cornea, which evaluated the state of the epithelium and the number of polymorphonuclear cells was also studied. RESULTS: The length of the neovessels was greater in the control group compared to the study group (P=<0.001). There was no difference in inflammation/vessel diameter between groups. Histopathology analysis showed that there was no difference between groups for the variables state of the epithelium and number of polymorphonuclear cells. The concordance analysis for the variable extension of the vessels and the variable inflammation/vessel diameter was estimated with Kappa coefficients of 0.705 and 0.500 respectively, indicating a good level of agreement in different evaluations and validating the method. CONCLUSIONS: The experimental model is adequate and can be reproduced to evaluate other drugs in the cornea. Bevacizumab inhibit the neovessels' growth but was not effective in preventing the inflammatory response. The drug did not delay the reepithelialization of the cornea.

Ação do bevacizumabe subconjuntival na neovascularização e re-epitelização corneana 25 dias após queimadura química / Effect of subconjunctival bevacizumab on corneal neovascularization and reepithelization 25 days after chemical burn

OBJETIVOS: Avaliar a ação do bevacizumabe subconjuntival em modelo experimental de neovascularização em córnea de coelho. Analisar se o modelo de avaliação empregado é adequado e comparar entre os grupos a extensão dos vasos, inflamação e re-epitelização da córnea. MÉTODOS: Estudo experimental, prospectivo em 20 coelhos submetidos a trauma químico com hidróxido de sódio a 1 N divididos em dois grupos, Imediatamente após a queimadura, o grupo tratado recebeu injeção subconjuntival de 0,15 ml (3,75 mg) de bevacizumabe e o grupo controle, injeção subconjuntival de 0,15 ml de soro fisiológico a 0,9 por cento. Após 25 dias, foi realizada análise fotográfica digital para avaliar a extensão e inflamação/calibre dos vasos segundo critério pré-estabelecido e estudo histopatológico da córnea, no qual foi avaliado o estado do epitélio e o número de polimorfonucleares. RESULTADOS: A extensão dos neovasos corneanos foi menor no grupo estudo em relação ao controle (p<0,001). Não houve diferença significativa entre os grupos na inflamação/calibre dos vasos. A análise histopatológica mostrou que não ocorreu diferença entre os grupos nas variáveis estado do epitélio e número de polimorfonucleares. A análise de concordância para a variável extensão dos vasos e para a variável inflamação/calibre dos vasos teve uma estimativa do coeficiente de Kappa respectivamente de 0,705 e 0,500 indicando bom grau de concordância nas diferentes avaliações cegadas, validando o método empregado. CONCLUSÕES: O modelo de avaliação foi adequado e pode ser reproduzido para avaliar outras drogas na córnea. O bevacizumabe inibiu a neovascularização corneana, porém não foi eficaz em reduzir o processo inflamatório. A droga não atrasou a re-epitelização da córnea.

PURPOSES: To evaluate the effect of subconjunctival bevacizumab in an experimental model of neovascularization in rabbit cornea. Determine its effect on vessels extension, inflammation, epithelialization of the cornea and whether the evaluation method used is appropriate to compare neovascular models. METHODS: Experimental, prospective, randomized, blinded study in twenty rabbits subjected to chemical trauma with sodium hydroxide at 1N divided into two groups. The study group received subconjunctival injection of 0.15 ml (3.75 mg) of bevacizumab and was compared with the control group that received subconjunctival injection of 0.15 ml saline solution. After 25 days, digital photographic analysis was performed to assess the vessel's extension and inflammation/diameter according to pre-established criteria. Histopathology of the cornea, which evaluated the state of the epithelium and the number of polymorphonuclear cells was also studied. RESULTS: The length of the neovessels was greater in the control group compared to the study group (P=<0.001). There was no difference in inflammation/vessel diameter between groups. Histopathology analysis showed that there was no difference between groups for the variables state of the epithelium and number of polymorphonuclear cells. The concordance analysis for the variable extension of the vessels and the variable inflammation/vessel diameter was estimated with Kappa coefficients of 0.705 and 0.500 respectively, indicating a good level of agreement in different evaluations and validating the method. CONCLUSIONS: The experimental model is adequate and can be reproduced to evaluate other drugs in the cornea. Bevacizumab inhibit the neovessels' growth but was not effective in preventing the inflammatory response. The drug did not delay the reepithelialization of the cornea.

Corneal reconstruction with tissue-engineered cell sheets composed of human immature dental pulp stem cells.

PURPOSE: To determine the outcome of the use of a tissue-engineered cell sheet composed of human undifferentiated immature dental pulp stem cells (hIDPSC) for ocular surface reconstruction in an animal model of total limbal stem cell deficiency (LSCD). METHODS: LSCD was induced by the application of 0.5 M NaOH to the right eye of rabbits for 25 seconds (mild chemical burn [MCB]) and for 45 seconds (severe chemical burn [SCB]). After 1 month, a superficial keratectomy was performed to remove the fibrovascular pannus that covered the animals' burned corneas. A tissue-engineered hIDPSC sheet was transplanted onto the corneal bed and then covered with deepithelialized human amniotic membrane (AM). In the respective control groups, the denuded cornea was covered with AM only. After 3 months, a detailed analysis of the rabbit eyes was performed with regard to clinical aspect, histology, electron microscopy, and immunohistochemistry. RESULTS: Corneal transparency of the rabbit eyes that underwent hIDPSC transplantation was improved throughout the follow-up, while the control corneas developed total conjunctivalization and opacification. Rabbits from the MCB group showed clearer corneas with less neovascularization. The clinical data were confirmed by histologic analysis that showed healthy uniform corneal epithelium, especially in the MCB group. The presence of hIDPSC was detected using an anti-hIDPSC antibody. The corneal tissue also showed positive immunostaining with anti-human antibodies. In the control corneas, none of these antigens were detected. CONCLUSIONS: Overall, these data showed that transplantation of a tissue-engineered hIDPSC sheet was successful for the reconstruction of corneal epithelium in an animal model of LSCD.

Human immature dental pulp stem cells share key characteristic features with limbal stem cells.

OBJECTIVES: Limbal stem cells (LSC) are self-renewing, highly proliferative cells in vitro, which express a set of specific markers and in vivo have the capacity to reconstruct the entire corneal epithelium in cases of ocular surface injury. Currently, LSC transplantation is a commonly used procedure in patients with either uni- or bilateral total limbal stem cells deficiency (TLSCD). Although LSC transplantation holds great promise for patients, several problems need to be overcome. In order to find an alternative source of cells that can partially substitute LSC in cornea epithelium reconstruction, we aimed at investigating whether human immature dental pulp stem cells (hIDPSC) would present similar key characteristics as LSC and whether they could be used for corneal surface reconstruction in a rabbit TLSCD model. MATERIALS: We used hIDPSC, which co-express mesenchymal and embryonic stem cell markers and present the capacity to differentiate into derivative cells of the three germinal layers. TLSCD was induced by chemical burn in one eye of rabbits. After 30 days, the opaque tissue formed was removed by superficial keratectomy. Experimental group received undifferentiated hIDPSC, while control group only received amniotic membrane (AM). Both groups were sacrificed after 3 months. RESULTS AND CONCLUSIONS: We have demonstrated, using immunohistochemistry and reverse transcription-polymerase chain reaction, that hIDPSCs express markers in common with LSC, such as ABCG2, integrin beta1, vimentin, p63, connexin 43 and cytokeratins 3/12. They were also capable of reconstructing the eye surface after induction of unilateral TLSCD in rabbits, as shown by morphological and immunohistochemical analysis using human-specific antibodies against limbal and corneal epithelium. Our data suggest that hIDPSCs share similar characteristics with LSC and might be used as a potential alternative source of cells for corneal reconstruction.

Morphological and functional evaluation of distal esophagus of rabbits submitted to esophageal infusion with caustic soda.

UNLABELLED: The ingestion of caustic substances is an important emergency situation, because of its serious consequences. PURPOSE: To study morphological and functional alterations of the esophagus in rabbits submitted to esophageal infusion of caustic soda (NaOH). METHODS: The 88 rabbits studied were divided into 4 groups: G1 (n=22) were submitted to esophageal infusion with distilled water. G2, G3, and G4 were submitted to esophageal infusion of 2%, 4% and 6% NaOH respectively. Morphological alterations were studied in 12 animals from each group and manometric alterations in the remaining 10. An analysis was made of lower esophageal sphincter (LES) pressure, number and amplitude of contractions in the distal third of the esophagus. These studies were performed before (moment M1) and at 30 minutes, 6 hours, and 24 hours after (moments M2, M3, and M4, respectively) esophageal infusion. RESULTS: Morphological evaluation: G1 - no alterations; G2 - edema, hyperemia, and ecdysis; G3 - enlarged calibre of esophagus, ulcers, ecdysis of mucosa; G4 - lesions similar to G3, but more intense, areas of extensive hemorrhage at M3 and M4. Functional evaluation: LES was higher at M2; the number of distal third lower esophageal contractions in G3, and G4 was lower; and the contraction amplitude was lower in G4. CONCLUSIONS: 1) Esophageal infusion with caustic soda in rabbits is a good experimental model for studying caustic esophagites. 2) Esophageal infusion with NaOH caused lesions in the esophageal wall, with gravity proportional to solution concentration; 3) Infusion caused LES spasm at M2, and reduced both contraction number and amplitude in the distal third of the esophagus.

Morphological and functional evaluation of distal esophagus of rabbits submitted to esophageal infusion with caustic soda

The ingestion of caustic substances is an important emergency situation, because of its serious consequences. PURPOSE: To study morphological and functional alterations of the esophagus in rabbits submitted to esophageal infusion of caustic soda (NaOH). METHODS: The 88 rabbits studied were divided into 4 groups: G1 (n=22) were submitted to esophageal infusion with distilled water. G2, G3, and G4 were submitted to esophageal infusion of 2 percent, 4 percent and 6 percent NaOH respectively. Morphological alterations were studied in 12 animals from each group and manometric alterations in the remaining 10. An analysis was made of lower esophageal sphincter (LES) pressure, number and amplitude of contractions in the distal third of the esophagus. These studies were performed before (moment M1) and at 30 minutes, 6 hours, and 24 hours after (moments M2, M3, and M4, respectively) esophageal infusion. RESULTS: Morphological evaluation: G1 - no alterations; G2 - edema, hyperemia, and ecdysis; G3 - enlarged calibre of esophagus, ulcers, ecdysis of mucosa; G4 - lesions similar to G3, but more intense, areas of extensive hemorrhage at M3 and M4. Functional evaluation: LES was higher at M2; the number of distal third lower esophageal contractions in G3, and G4 was lower; and the contraction amplitude was lower in G4. CONCLUSIONS: 1) Esophageal infusion with caustic soda in rabbits is a good experimental model for studying caustic esophagites. 2) Esophageal infusion with NaOH caused lesions in the esophageal wall, with gravity proportional to solution concentration; 3) Infusion caused LES spasm at M2, and reduced both contraction number and amplitude in the distal third of the esophagus.

A ingestão de substâncias cáusticas constitui importante situação de emergência, tendo em vista a gravidade de suas seqüelas. OBJETIVO: Estudar as alterações morfológicas e funcionais do esôfago de coelhos submetidos à infusão esofágica com soda cáustica (NaOH). MÉTODOS: 88 coelhos foram divididos em 4 grupos: G1 (n=22) foi submetido à infusão esofágica com água destilada; G2, G3 e G4 foram submetidos a infusão esofágica com NaOH a 2 por cento, 4 por cento e 6 por cento, respectivamente. Alterações morfológicas foram estudadas em 12 animais de cada grupo e as alterações manométricas, nos 10 animais restantes. Foram feitas análises do esfíncter inferior do esôfago (EIE), número e amplitude das contrações no terço distal do esôfago. Estes estudos foram realizados antes (momento 1 - M1) e aos 30 minutos, 6 horas e 24 horas após a infusão esofágica (momentos M2, M3 e M4, respectivamente). RESULTADOS: Avaliação macroscópica: G1 - sem alterações; G2 - edema, hiperemia e descamação; G3 - aumento do calibre do esôfago, úlceras, descamação da mucosa; G4 - lesões semelhantes as do G3, porém mais intensas, áreas de extensa hemorragia. Avaliação funcional: a pressão no EIE foi mais elevada em M2 no grupo 2; o número das contrações no terço distal do esôfago foi menor em G3 e G4, e a amplitude das contrações foi menor em G4. CONCLUSÕES: 1) a infusão esofágica com NaOH constitui excelente modelo experimental de esofagite cáustica no coelho; 2) a infusão esofágica com NaOH causa lesões na parede do esôfago, com gravidade proporcional a concentração da solução; 3) a infusão causou espasmo do EIE em M2 e redução do número e amplitude das contrações no terço distal do esôfago.

Effects of time of contact and concentration of caustic agent on generation of injuries.

OBJECTIVES: Solid caustic soda (CS) ingestion levels continue high in Brazil. The aggressiveness of a caustic agent depends, among other factors, on its concentration and time of contact with mucosa. However, the interdependence of these factors in the production of caustic lesion in the esophageal mucosa is not known, especially regarding CS as the strongest corrosive agent. We analyze the effects of concentration and time of contact on the aggressiveness of CS to the esophagus of live animals. STUDY DESIGN/METHODS: One milliliter of CS at concentrations between 1.83% and 73.33% was applied to rats. The solution was kept in contact with the mucosa for 10 to 120 minutes. Internal and external organ aspects were analyzed and the epithelium, submucosa, muscle layer, and adventitia were analyzed microscopically RESULTS: Epithelial necrosis was observed at all concentrations. Among the necrotic layers, the submucosa was observed starting at the 7.33% concentration, and the muscular layer and adventitia were observed at 14.66% concentration. Damage to the pulmonary parenchyma and trachea occurred at 33.66% after 10 minutes, and perforation of the esophagus was observed only after 120 minutes. After 10 minutes, important corrosive lesions installed in the esophageal layers, expanding in depth and superficial extension. The use of heparin had no effect on the production of lesions. CONCLUSIONS: Ten minutes were sufficient to provoke necrosis, and longer contact increased the area of necrosis. Solution concentration levels were more important in damage production: 1.83% was sufficient for epithelial necrosis, 7.33% caused submucosal necrosis, and 14.66% muscle and adventitia necrosis; 33.66% solutions caused lung and trachea damage after 10 minutes and esophageal perforation after 120 minutes.

Does amniotic membrane transplantation improve the outcome of autologous limbal transplantation?

PURPOSE: To evaluate the additional benefits of amniotic membrane transplantation (AMT) when combined with conjunctival limbal autograft (CLAU) in the treatment of chronic chemical burns. METHODS: Thirty eyes of 30 rabbits underwent a chemical burn to create limbal deficiency. Forty-five days later, the animals were randomized into three groups of 10 rabbits each. Eyes from group 1 were treated with CLAU, group 2 underwent CLAU and AMT, and group 3 served as control without surgery. Corneal vascularization and opacity were documented with external photographs at postoperative days 30, 60, and 90. The rabbits were killed 3 months after surgery, and their corneas divided into two halves. One half was prepared for hematoxylin-eosin and periodic acid-Schiff staining and the other for frozen sections and immunostaining with AM3 (to MUC 5AC mucin) and AE5 (to K3 keratin). Final clinical outcome was also scored using external photographs at the last follow-up examination. RESULTS: After chemical burn, all groups showed similar degrees of conjunctivalization. After transplantation, corneal vascularization was worse in controls at 60 and 90 days (p < 0.001). At 30 days, eyes from group 1 had less corneal opacity (p < 0.05). At 90 days, corneal opacity was worse in controls but the same in groups 1 and 2 (p < 0.05). At the same time, limbal deficiency was significantly worse in controls (p < 0.05) but similar between groups 1 and 2. Corneal phenotype was present in 70% of the eyes in group 1, 50% in group 2, but in 10% of the controls. Clinical success with clear corneas was significantly more common in groups 1 and 2 when compared with controls (p < 0.001). CONCLUSIONS: CLAU is effective in treating limbal deficiency. The concurrent AMT does not add benefits in this rabbit model of chemical burns.

Amniotic membrane transplantation for partial and total limbal stem cell deficiency secondary to chemical burn.

PURPOSE: To evaluate the surgical outcome of preserved amniotic membrane transplantation (AMT) for ocular surface reconstruction in chemical burn with limbal stem cell deficiency. DESIGN: Prospective, noncomparative, interventional case series. PARTICIPANTS: Twenty eyes of 20 consecutive patients with limbal stem cell deficiency secondary to ocular chemical injury. INTERVENTION: AMT with or without adjunctive limbal transplantation using limbal tissue from either the healthy contralateral eye (CLAU) or a living related donor (lr-CLAL). MAIN OUTCOME MEASURES: Reconstruction of corneal epithelium (clear appearance without epithelial defect, normal fluorescein permeability and the absence of conjunctiva-derived goblet cells on impression cytology), decrease in corneal vascularization and improvement in visual acuity. RESULTS: With a mean follow-up time of 19 months (range, 8-27 months), satisfactory ocular surface reconstruction was obtained in 15 eyes (75%), with reduced inflammation and vascularization of the ocular surface and a mean epithelialization time of 3.3 weeks. Success was observed in all cases of partial limbal stem cell deficiency (PLD) and in 68.75% (11 eyes) of cases of total limbal stem cell deficiency (TLD). Surgical failure was observed in five severe cases (31.25%). A significant visual improvement was observed in all cases after surgery, except for 2 eyes that maintained preoperative visual acuity. CONCLUSIONS: AMT seems to be an efficient adjunct for ocular surface reconstruction in chemical burns with PLD. When performed in conjunction with limbal stem cell transplantation, it is also effective in most cases of TLD.