Rat models of high risk colorectal anastomoses

Abstract Purpose: To evaluate the most frequent surgical techniques of high-risk colorectal anastomoses in rats. Methods: Wistar rats were enrolled in three different models comprising inflammatory (TNBS enema), vascular (portal vein occlusion) or obstructive (a non-ischemic constricting ring) mechanisms associated with colonic anastomosis that had accomplished after these former lesions. Histological analyses (Hematoxylin and eosin and Picrosirius red) were performed. Results: All anastomoses techniques were associated with risk factors and had complications, mainly anastomotic leakage. In Study 1, the use of a pharmacological agent, trinitrobenzene sulfonic acid (TNBS) mimicked an inflammatory bowel disease such as Crohn's disease with 50% of anastomosis leakage, the higher percentage among all models tested. In Study 2, after portal ischemia followed by reperfusion it was observed a dense neutrophil infiltrate in the midst of necrotic tissue and fibrin at the anastomotic site and 5 days after the anastomosis, no collagen was produced. In Study 3, 5 days after the mechanical obstruction some denuded areas of epithelium with marked oedema of mucosa and submucosa were seen, at the anastomotic site and anastomosis group showed some reduction of collagen density when compared with Control/Sham group. Conclusion: All the experimental surgical techniques tested in rats were associated with high-risk colorectal anastomoses and were useful to study colonic anastomotic healing and intestinal leakage.

A technical note on low cost rat laparoscopy an initial experience

Abstract Purpose: To evaluate a novel and adapted low-cost set model for laparoscopic surgery in rats. Methods: Nine Wistar rats underwent two different laparoscopic procedures, splenectomy (n=3) and distal pancreatectomy with splenectomy (n = 6), after assembling a low-cost set replacing the conventional one (monitor, micro camera, image processor, light source, laparoscope and insufflator). The new set included an Android Tablet 10.5 ", a 5mm USB Endoscope and semiautomatic sphygmomanometer monitor. Results: The same surgeon performed the laparoscopic procedures. Total surgical time ranged from 36 to 60 minutes with a mean of 45.8 minutes. Three rats died during the distal pancreatic and splenectomy procedure (33.3%), due to respiratory failure (n = 1), uncontrolled abdominal hemorrhage (n=1) and iatrogenic gastric perforation (n = 1). We followed the other six rats (66.6%) for seven days with no further evidence of complications. Conclusions: The laparoscopic partial pancreatectomy and splenectomy can be performed with the novel low-cost set assembled in the present experimental study. Both specific training and skills development are required to validate more advanced laparoscopic procedures and achieve a desirable outcome.

Cholecystectomy during ceftriaxone therapy. A translational study with a new rabbit model

Abstract Purpose: To evaluate the actual incidence of both microlithiasis and acute cholecystitis during treatment with intravenous ceftriaxone in a new rabbit model. Methods: New Zealand rabbits were treated with intravenous ceftriaxone or saline for 21 days. Ultrasound monitoring of the gallbladder was performed every seven days until the 21st day when histopathology, immunohistochemistry for proliferating cell nuclear antigen (PCNA), pro-caspase-3 and CD68, liver enzyme biochemistry, and chromatography analysis of the bile and sediments were also performed. Results: All animals treated with ceftriaxone developed acute cholecystitis, confirmed by histopathology (P<0.05) and biliary microlithiasis, except one that exhibited sediment precipitation. In the group treated with ceftriaxone there was an increase in pro-caspase-3, gamma-glutamyl transpeptidase concentration, PCNA expression and in the number of cells positive for anti-CD68 (P<0.05). In the ceftriaxone group, the cholesterol and lecithin concentrations increased in the bile and a high concentration of ceftriaxone was found in the microlithiasis. Conclusion: Ceftriaxone administered intravenously at therapeutic doses causes a high predisposition for lithogenic bile formation and the development of acute lithiasic cholecystitis.

Student insight about the discipline of surgical technique on the formative process in the School of Medicine of UFRJ

Abstract Purpose: To evaluate whether undergraduate students feel motivated to develop surgical skills and know their impression about the importance of having a surgical technique discipline in the curriculum of a medical school. Methods: A prospective study including three classes in a row, from the 8th period (n = 265) evaluated the knowledge acquired at the Center of Experimental Surgery, Department of Surgery, School of Medicine of Federal University of Rio de Janeiro (UFRJ). The importance of the discipline for medical training as a way of encouragement to arouse and deepen the interest in surgical technique was emphasized. The questions were scored from 1 to 5 (worst to best grade) . Results: Concerning the importance of the discipline for medical training, 78% and 18% of the students assigned a score 5 and 4, respectively. Regarding the stimulus to improve their surgical technical skills, 40% and 32% attributed the score 5 and 4, respectively. Conclusion: Undergraduate students from the Medical School of UFRJ effectively shared the understanding that the operative technique bases improve the formative process with significant impact, not only in the development of skills, but also to arouse vocations and stimulate new attitudes aimed to knowledge acquirement in the field of Surgery.

Effects of low-level laser therapy on wound healing / Efeitos da laserterapia de baixa potência na cicatrização de feridas cutâneas

OBJECTIVE: To gather and clarify the actual effects of low-level laser therapy on wound healing and its most effective ways of application in human and veterinary medicine. METHODS: We searched original articles published in journals between the years 2000 and 2011, in Spanish, English, French and Portuguese languages, belonging to the following databases: Lilacs, Medline, PubMed and Bireme; Tey should contain the methodological description of the experimental design and parameters used. RESULTS: doses ranging from 3 to 6 J/cm2 appear to be more effective and doses 10 above J/cm2 are associated with deleterious effects. The wavelengths ranging from 632.8 to 1000 nm remain as those that provide more satisfactory results in the wound healing process. CONCLUSION: Low-level laser can be safely applied to accelerate the resolution of cutaneous wounds, although this fact is closely related to the election of parameters such as dose, time of exposure and wavelength. .

OBJETIVO: reunir e esclarecer quais os reais efeitos da laserterapia de baixa potência sobre feridas cutâneas e suas formas mais eficazes de aplicação na medicina humana e veterinária. MÉTODOS: foram pesquisados Artigos Originais publicados em periódicos pertencentes às seguintes bases de dados: Lilacs, MedLine, Bireme e PubMed entre os anos de 2000 e 2011, na línguas espanhola, inglesa, francesa e portuguesa, que contivessem a descrição metodológica do modelo experimental e parâmetros utilizados no estudo. RESULTADOS: doses compreendidas entre 3-6 J/cm2 parecem ser mais eficazes e que doses acima de 10 J/cm2 estão associadas a efeitos deletérios. Os comprimentos de onda compreendidos entre 632,8-1000nm seguem como aqueles que apresentam resultados mais satisfatórios no processo de cicatrização tecidual. CONCLUSÃO: o laser de baixa potência pode ser indicado com segurança para acelerar a resolução de feridas cutâneas, muito embora este fato esteja intimamente ligado à eleição de parâmetros como dose, tempo e comprimento de onda. .

Molars extraction for bone graft study in rabbits / Extração de molares para estudos de enxertos ósseos em coelhos

PURPOSE: The aim of this study was to describe an experimental surgical technique to be used in the evaluation of bone grafts in rabbits. METHODS: The operative technique was performed in jaws, with external approach from the labial commissure to the last molar tooth. An incision about 1cm extended forward to the alveolar ridge, followed by a exposing the cervical region of the alveolar bone and dental elements was done. Thus, after extraction of first molar with forceps, the tooth socket left was filled with hydroxyapatite. The bone gain was analyzed by histopathological studies. RESULTS: The histological analyses indicated formed bone surrounding the biomaterial. CONCLUSION: The experimental model using the tooth socket of the rabbit molar is a feasible procedure for studies of bone grafts.

OBJETIVO: Descrever uma técnica cirúrgica em coelhos para avaliação de enxertos ósseos. MÉTODOS: A técnica operatória consiste numa incisão na topografia da comissura labial até o ultimo molar. Uma incisão de 1cm no rebordo para expor o osso alveolar e a região cervical dos molares. Realizou-se a exodontia com fórceps e o alvéolo é preenchido com hidroxiapatita. Após o tempo de cicatrização é realizada a avaliação histológica. RESULTADOS: A análise histológica mostrou o novo osso formado rodeando biomaterial. CONCLUSÃO: O modelo cirúrgico para avaliação de enxertos ósseos utilizando molares de coelhos se mostrou factível.

Characterization of pseudarthrosis with ultrasound backscattered signals in rats / Caracterização da pseudoartrose com sinais de retroespalhamentos de ultrassom em ratos

PURPOSE: To propose a novel model of pseudarthrosis in a small animal and to investigate the ability of backscatter parameters from ultrasound signals in differentiating normal bone from those ones with pseudarthorsis. METHODS: Twelve Rattus norvegicus albinus free from pathogenic species (SPF) were randomly divided in two groups, with six animals each. In the Control group a surgical approach to the femur was made, followed by the synthesis of the muscle and skin layers. The Experimental group was submitted to an osteotomy of the femur and a vascularized flap of the fascia lata was interposed in the line of the fractured bone. Then the alignment and bone stabilization were accomplished, by using nylon stitch in U shape introduced in holes made in the proximal and distal fractured bone. Bone samples were scanned with ultrasound and signals were collected for each one to analyze the parameter Apparent Integrated Backscatter - AIB. RESULTS: Radiological and anatomopathologic studies revealed the absence of bone consolidation with persistence of fiber-osteoid tissue. Values of the ultrasound parameter AIB from normal bones were statistically different from those with pseudarthrosis. CONCLUSION: The experimental model was suitable for pseudarthrosis development in rats and the ultrasound backscatter parameters were able to identify such a bone disease in vitro.

OBJETIVO: Propor um novo modelo de pseudoartrose em animais de pequeno porte e investigar o potencial de parâmetros de retroespalhamento de ultrassônico em diferenciar osso normal e com pseudoartrose. MÉTODOS: Doze Rattus norvegicus albinus (SPF) foram distribuídos aleatoriamente em dois grupos, tendo cada grupo seis animais. No grupo Controle realizou-se uma abordagem cirúrgica ao fêmur, seguida da síntese por planos do músculo e da pele. O grupo Experimental foi submetido à osteotomia do fêmur aduzida da confecção de um retalho pediculado de fascia lata para interposição entre os segmentos resultantes da fratura induzida cirurgicamente. Prosseguiu-se com o alinhamento e estabilização óssea, mediante a confecção de um nó com fio de náilon em formato de U, introduzido em orifícios efetuados nas extremidades proximal e distal à fratura. As amostras ósseas foram irradiadas pelo ultrassom e sinais foram coletados para cada uma no intuito de analisar o parâmetro Retroespalhamento Integrado Aparente - AIB. RESULTADOS: Estudos radiológicos e anatomopatológicos evidenciaram a ausência de consolidação óssea com persistência de tecido fibro-osteóide. Os valores de AIB para ossos normais foram estatisticamente diferentes em relação aos ossos com pseudoartrose. CONCLUSÃO: O modelo experimental apresentou-se adequado para a formação de pseudoartrose em ratos e o parâmetro de retroespalhamento de ultrassom foi capaz de detectar tal doença óssea, in vitro.

Modelo experimental em ratos para o desenvolvimento de pseudoartrose / Experimental model in rats for the development of pseudoarthrosis

OBJETIVO: Descreve-se a técnica de um novo um modelo de pseudoartrose em Rattus norvegicus albinus livre de espécies patogênicas (SPF). MÉTODOS: Os animais foram aleatoriamente distribuídos em dois Grupos: Grupo 1 - Controle (n =6), Grupo 2 - Experimental (n =6). No grupo Controle realizou-se um acesso ao fêmur, seguido da síntese por planos do músculo e da pele. O grupo Experimental foi submetido à osteotomia do fêmur aduzida da confecção de um retalho pediculado de fáscia lata para interposição entre os segmentos resultantes da fratura induzida cirurgicamente. Prosseguiu-se com o alinhamento e aproximação dos segmentos ósseos, mediante uso de fios de náilon introduzidos em orifícios efetuados na extremidade proximal e distal. RESULTADOS: Estudos radiológico e anatomopatológico evidenciaram a ausência de consolidação óssea com persistência de tecido fibro-osteóide decorridos 120 dias de evolução pós-operatória. CONCLUSÃO: O modelo experimental é adequado para a formação de pseudoartrose em ratos.

OBJECTIVE: We sought to describe a new model of pseudoarthrosis in rats free of pathogenic species (Rattus norvegicus albinus - SPF). METHODS: The animals were randomly distributed into two groups were used: Group 1 - Control (n =6); Group 2 - Experimental (n =6). In the Control group an access to the femur followed by the synthesis of the muscular and skin layers was done. The Experimental group was submitted to osteotomy of the femur and a pedicle flap of the fascia lata was interposed between the segments resulting from the surgically induced fracture. The procedure was carried on with both alignment and approximation of the fractured bone through the use of mononylon thread introduced into holes created in the proximal and distal. RESULTS: Radiological and anatomopathological studies showed the absence of bone consolidation with persistence of fibro-osteoid tissue up to 120 days of follow-up. CONCLUSION: The experimental model is suitable for the development of a pseudoarthrosis in rats.

Estudo da técnica da sindesmoplastia extra-articular com fascia lata autógena: modelo em cães / Study of the extra articulate syndesmoplasty technique with autogenous fascia lata: a model in dogs

OBJETIVO: Avaliar a eficácia da técnica extra-capsular para o tratamento de ruptura do ligamento cruzado anterior em cães. MÉTODOS: Foi realizada a reparação cirúrgica extra-articular, sem artrotomia do ligamento cruzado anterior, com a utilização da fáscia lata autógena para estabilização da articulação do joelho em seis animais que apresentaram claudicação grave e movimento de gaveta positivo. RESULTADOS: A técnica cirúrgica extra-articular foi eficaz com boa estabilização articular e evolução satisfatória. CONCLUSÃO: A via extra capsular com uso da fáscia lata para correção da ruptura do ligamento cruzado anterior mostrou-se útil haja vista tratar-se de um procedimento simples e de rápida execução, causando o mínimo dano tecidual e recuperação pós-operatória eficiente.

OBJETIVE: To evaluate extra-capsular technique for the treatment of the anterior cruciate ligament rupture, in dogs. METHODS: It was performed an extra-articulate surgery without arthrotomy of the anterior cruciate ligament by using a strip of the autogenous fascia lata for stabilization of the knee joint in six animals which had severe claudication and drawer movement sign positive. RESULTS: The extra articulate technique was effective with good knee stabilization and satisfactory outcome. CONCLUSION: The use of the fascia lata with an extra capsular technique to fix the rupture of the anterior cruciate ligament seems to be useful once it is a simple and rapid procedure with minimum tissue damage and efficient postoperative recovery.

Modelo cirúrgico de insuficiência renal crônica: estudo em coelhos / Surgical model of chronic renal failure: study in rabbits

OBJETIVO: Estabelecer um modelo de insuficiência renal crônica (IRC) em coelhos, com perspectivas de seu uso para ações terapêuticas e reparadoras. MÉTODO: Foram utilizados 19 coelhos da linhagem Nova Zelândia, machos, adultos, aleatoriamente distribuídos em três Grupos: Grupo 1 - Controle (n =5), Grupo 2- Simulação (n =7), Grupo 3 - Experimental (n =7). Os animais foram anestesiados com Cetamina e Diazepam e Fentanil por via intramuscular e Sevorane, através de vaporizador. No Grupo 3 realizou-se uma nefrectomia bipolar esquerda e após quatro semanas, uma nefrectomia direita. Todas as amostras do parênquima renal foram pesadas. O Grupo 2 foi submetido a duas laparotomias, sem nefrectomia.. Em todos os grupos foram realizadas avaliações: bioquímicas com dosagens de uréia, creatinina, sódio e potássio; ultra-sonográficas abdominais; cintigráficas e histológicas. RESULTADOS: No Grupo 3 houve aumento progressivo da uréia (p=0.0001), creatinina (p=0,0001), sódio (p= 0,0002) e potássio (p=0,0003). A comparação destes resultados com os dos Grupos 1 e 2, nos diversos intervalos, também revelou elevação sérica, com significância estatística (p < 0,05). A ultra-sonografia identificou aumento do rim esquerdo no grupo 3, após 16 semanas. A cintigrafia comprovou, na 4ª semana, perda de 75 por centoda massa renal esquerda. No Grupo 3, a avaliação histológica evidenciou fibrose subcapsular e intersticial e regeneração tubular. CONCLUSÃO: O modelo experimental de IRC é exeqüível, com sobrevida dos animais, em médio prazo, o que permite o uso deste intervalo como janela terapêutica para testar diferentes ações reparadoras ao parênquima renal comprometido.

OBJECTIVES: To establish a model of chronic renal failure in rabbits, with perspectives of its use for therapeutic and repairing actions. METHODS: Nineteen males, adults rabbits (New Zealand) randomly distributed into three groups were used: Group 1 - Control (n =5); Group 2-Sham (n =7); and Group 3 - Experimental (n =7). They were anaesthetized by using intramuscular Cetamine, Diazepam and Fentanyl followed by Sevorane with vaporizer device. In Group 3, a bipolar left nephrectomy was carried out and after four weeks, it was also done a right nephrectomy. All the samples of the renal tissue were weighed. The Group 2 was only submitted to both abdominal laparotomies, without nephrectomy. Biochemical evaluations, with urea, creatinina, sodium and potassium measurement; abdominal ultrasound scan; scintigraphy and histological analysis were performed in all animals. RESULTS: In group 3 there was a progressive increase of urea (p=0.0001), creatinine (p=0.0001), sodium (p = 0,0002) and potassium (p=0,0003). The comparison of these results with those one of the Groups 1 and 2, in all intervals, revealed blood rising with statistical significant level (p < 0,05). In Group 3, the ultrasound scan identified an increasing of the left kidney size, after 16 weeks and at the 4th week the scintigraphy confirmed the loss of 75 percent of the left renal mass. In the same group, the histological evaluation showed subcapsular and intersticial fibrosis and also tubular regeneration. CONCLUSION: The experimental model of IRC is feasible, with animal's survival in middle term which allows the use of this interval like a therapeutic window for testing different approaches in order to repair the kidney damages.