Manoel Luiz Ferreira

Modelo cirúrgico de insuficiência renal crônica: estudo em coelhos

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% 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 animals 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.

Heterologous mesenchymal stem cells successfully treat femoral pseudarthrosis in rats.

BackgroundThis study evaluated the effectiveness of treating pseudarthrosis in rats by using bone marrow cell suspensions or cultures of bone marrow mesenchymal stromal cellsMethodsThirty-eight specific pathogen-free (SPF) animals were randomly assigned to four groups: Group 1, Control, without surgical intervention; Group 2 (Placebo), experimental model of femoral pseudarthrosis treated only with saline solution; Group 3, experimental model of femoral pseudarthrosis treated with heterologous bone marrow cells suspension; Group 4, experimental model of femoral pseudarthrosis treated with cultures of heterologous mesenchymal stromal cells from bone marrow. When pseudarthrosis was confirmed by simple radiological studies, digital radiography and histopathology after a 120-day postoperative period, Groups 2, 3 and 4 were treated as above. At 30, 60 and 90 days after the treatment, all animals were evaluated by simple radiological studies, and at the end of the experiment, the animals were assessed by computed axial tomography and anatomopathological and histomorphometric examinations.ResultsInjected cells were detected in the areas affected by pseudarthrosis using scintigraphy within the first 24 hours after their administration. After 60 days, the animals of Group 3 showed callus formation while the animals of Group 4 presented periosteal reaction and had some consolidated areas. In contrast, Group 2 showed a predominance of fibro-osteoid tissue. After 90 days, bone consolidation and remodeling was observed in all animals from Group 3 whereas animals from Group 4 exhibited partial consolidation and those ones from Group 2 persisted with pseudarthrosis.ConclusionThe treatment with heterologous bone marrow cells suspension proved to be effective in the treatment of pseudarthrosis whereas cultures of heterologous bone marrow mesenchymal stromal cells did not show the same potential to aid bone healing.

Molars extraction for bone graft study in rabbits

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.

Characterization of pseudarthrosis with ultrasound backscattered signals in rats

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 pseudarthrosis. 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.

Modelo experimental em ratos para o desenvolvimento de pseudoartrose

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

OBJECTIVE 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.

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

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.

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

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.

Ureteral reconstruction with abdominal wall muscle flap: experimental study in rabbits

The authors detail the experimental development of a technique for the reconstruction of the ureter using a tubular shape, muscle flap of the abdominal wall. the preliminary results indicate the feasibility of this surgical technique.

Estudo da sutura do parênquima renal com fio absorvível sintético Aspectos histológicos

The interaction of synthetic absorbable suture with the renal parenchyma has not been demonstrated. This enables to check the aspect related to the influence on the healing and function of this organ. The aim of this study is to ascertain what consequences result when synthetic absorbable suture is applied in renal tissue. We used 10 male rats, weighing 250g, SPF origin, divided into 2 groups (n = 5). A sutured using polyglactin and other sham . The incision in the renal parenchyma than 1 cm long and 0.5 cm deep, 0.5 cm away and parallel to the hilum, on the ventral kidney. Followed by interrupted suture. The postoperative period of 90 days. The data analyzed include adhesion, atrophy and histopathological study. The finding indicates inflammatory reaction in the attachment areas and absence of residues of the suture, but with glomerular empairement.