RESUMO
OBJECTIVE: This study investigated the role of glutamine (Gln) on bacterial translocation in an intestinal obstruction model by using Escherichia coli labeled with technetium 99m (99mTc-E. coli). METHODS: Intestinal obstruction was performed by a single ligature of the terminal ileum in rats. Animals in the control group (group 1) were sham operated (not obstructed). Experimental group 2 had intestinal obstruction. Groups 1 and 2 were not treated with Gln. Groups 3 and 4 were treated with Gln for 7 d before surgery with 250 and 500 mg x kg(-1) x d(-1), respectively. A suspension containing 100 million colony-forming units/mL of (99m)Tc-E. coli was injected into the lumen of the ileum. Twenty-four hours after surgery, blood, mesenteric lymph nodes, livers, spleens, and lungs were collected for determination of radioactivity. The Mann-Whitney U test was performed for statistical analysis. P Assuntos
Translocação Bacteriana
, Escherichia coli/fisiologia
, Glutamina/uso terapêutico
, Obstrução Intestinal/microbiologia
, Animais
, Modelos Animais de Doenças
, Relação Dose-Resposta a Droga
, Escherichia coli/efeitos dos fármacos
, Obstrução Intestinal/patologia
, Masculino
, Distribuição Aleatória
, Ratos
, Ratos Wistar
RESUMO
OBJECTIVES: To assess the viability and induction of immunotolerance of nonvascularized splenic alloimplants. The phagocytic functions of splenic implants also were studied. MATERIALS AND METHODS: Thirty-six adult female New Zealand and California rabbits were used, and these animals were divided into the following 5 groups: (n = 6 / groups 1-4) group 1 (sham operations); group 2 (total splenectomy); group 3 (implantation of autologous sliced splenic tissue in the greater omentum following splenectomy); group 4 (implantation of allogenic sliced splenic tissue in the greater omentum after splenectomy); and group 5 (n = 12) (implanting allogenic sliced splenic tissue in the greater omentum after splenectomy and receiving oral cyclosporine at a dosage of 40 mg/kg/d). All animals were followed for 120 days after the operations, then received venous injections of China ink (groups 1, 2, 3, 4, 5A) or a colloidal radiopharmaceutical (group 5B), and subsequently underwent reoperations. Hematimetric examinations were performed, and the histologic aspects and phagocytic functions of the implants were assessed. RESULTS: Spontaneous immunotolerance was not induced by sliced splenic allografts implanted in the greater omentum. The use of cyclosporine did not preserve the viabilities of the implants. All animals in group 3, which were subjected to autologous implants, exhibited viable implants that exhibited phagocytic function, although this phagocytic function was reduced compared with that of the normal spleen. CONCLUSIONS: No viable spleen alloimplants were observed regardless of the presence of cyclosporine. Spontaneous immunotolerance was not induced by sliced splenic alloimplants.
Assuntos
Omento/cirurgia , Baço/transplante , Transplante Heterotópico , Aloenxertos , Animais , Ciclosporina/farmacologia , Feminino , Sobrevivência de Enxerto , Imunossupressores/farmacologia , Modelos Animais , Fagocitose , Coelhos , Cintilografia , Baço/diagnóstico por imagem , Baço/imunologia , Baço/patologia , Fatores de Tempo , Sobrevivência de Tecidos , Tolerância ao TransplanteRESUMO
BACKGROUND: Metal implants are used frequently in orthopedic procedures and the occurrence of subclinical low-virulence infection is difficult to diagnose. The objective of this study was to examine the hypothesis that peri-prosthetic subclinical infections may be diagnosed effectively in a murine model system using scintigraphic imaging with (99m)Tc-labeled ceftizoxime. METHODS: A sample population of 3-mo old Wistar rats (mean weight 327 g) was divided randomly into a control group (n=6), which received sterile implants, and an experimental group (n=6), which received implants contaminated with Staphylococcus aureus strain ATCC6538-P. Animals were anesthetized and femoral titanium implants were fixed beneath muscle tissue in left hind limbs. Three weeks after surgery, animals were injected with (99m)Tc-ceftizoxime solution (62.9 MBq) and scintigraphic images were obtained at 3.5 and 6.5 h after tracer injection. RESULTS: According to the scintigraphic images, the radiopharmaceutical showed affinity for the operated thigh areas of experimental animals but not for those of the control group. There was no difference between the control and experimental groups regarding the amount of radioactivity in the regions of interest measured at 3.5 h after injection of radiolabeled antibiotic, but the between-group difference determined at 6.5 h after treatment was statistically significant (p=0.026). Moreover, the level of radioactivity recorded in resected thigh tissues derived from experimental animals was greater than that of the control group (p=0.035). CONCLUSION: (99m)Tc-ceftizoxime scintigraphy can localize preferentially periprosthetic-infected areas adjacent to metal implants in a murine model. Furthermore, the radiolabeled antibiotic appears to be capable of detecting alterations in the micro-environment close to the implant and of reaching the bacteria attached to the implant surface.
Assuntos
Infecções Assintomáticas , Ceftizoxima/administração & dosagem , Marcação por Isótopo/métodos , Compostos de Organotecnécio/administração & dosagem , Implantação de Prótese/efeitos adversos , Cintilografia/métodos , Infecção da Ferida Cirúrgica/diagnóstico , Animais , Modelos Animais de Doenças , Ratos Wistar , TitânioRESUMO
PURPOSE: To evaluate whether scintigraphy with technetium-99m-labeled ceftizoxime ((99m)Tc-CFT) can differentiate mediastinitis from aseptic inflammation associated with sternotomy. METHODS: Twenty female Wistar rats were randomly distributed into four groups: S (control) -partial upper median sternotomy with no treatment; SW (control) - sternotomy and treatment of sternal wounds with bone wax; SB - sternotomy and infection with Staphylococcus aureus; SWB - sternotomy with bone wax treatment and bacterial infection. Scintigraphy with (99m)Tc-CFT was performed eight days after surgery and images were collected 210 and 360 min after infusion of the radiopharmaceutical. RESULTS: No animals exhibited clinical signs of wound infection at the end of the experiment, although histological data verified acute inflammatory response in those experimentally infected with bacteria. Scintigraphic images revealed that tropism of (99m)Tc-CFT to infected sternums was greater than to their non-infected counterparts. Mean counts of radioactivity in bacteria-infected sternal regions (SB and SWB) were significantly higher (p = 0.0007) than those of the respective controls (S and SW). CONCLUSION: Scintigraphy with technetium-99m-labeled ceftizoxime is a method that can potentially detect infection post sternotomy and differentiate from aseptic inflammation in animals experimentally inoculated with S. aureus.
Assuntos
Ceftizoxima/análogos & derivados , Mediastinite/diagnóstico por imagem , Compostos de Organotecnécio , Esternotomia/efeitos adversos , Esterno/diagnóstico por imagem , Infecção da Ferida Cirúrgica/diagnóstico por imagem , Animais , Modelos Animais de Doenças , Feminino , Cintilografia , Distribuição Aleatória , Ratos Wistar , Reprodutibilidade dos Testes , Infecções Estafilocócicas/diagnóstico por imagem , Staphylococcus aureus , Esterno/microbiologia , Infecção da Ferida Cirúrgica/microbiologiaRESUMO
OBJECTIVE: To evaluate the splenic parenchymal blood distribution through scintigraphic study. METHODS: Thirty Wistar rats were randomly divided into six groups (n = 5). Group 1 (spleen - 30 minutes) and Group 2 (spleen - 90 minutes) underwent laparotomy with direction of blood flow to the spleen by ligature of the aorta near the iliac bifurcation and splanchnic vessels, keeping blood flow only in the splenic artery; Group 3 (spleen and stomach - 30 minutes) and Group 4 (spleen and stomach - 90 minutes) underwent laparotomy with direction of blood flow to the spleen and stomach by ligature of the aorta near the iliac bifurcation and splanchnic vessels, maintaining the flow through the splenic, gastric and splenogastric vessels; Group 5 (control - 30 minutes) and Group 6 (control - 90 minutes) underwent laparotomy and ligation of the aorta near the iliac bifurcation, keeping the flow to the abdominal organs. After arterial ligation, the animals received an injection of 0.2 ml of sodium pertechnetate in the aorta. Scintigraphic images were taken and the animals had their spleens removed for radioactivity counting with an automatic counter device. RESULTS: There was no difference in the amounts of radiation from the spleen between groups, indicating retention of the radioisotope by the spleen, even after the period of 90 minutes. CONCLUSION: The blood flow through the spleen is not continuous. The blood diffuses through the splenic parenchyma and its venous drainage is slow, not following a predictable sequence.
Assuntos
Fluxo Sanguíneo Regional , Baço/irrigação sanguínea , Animais , Feminino , Cintilografia , Distribuição Aleatória , Ratos , Ratos WistarRESUMO
PURPOSE: To evaluate the effectiveness of the use of the povidone-iodine (PVI) added to the liquid of wash of the peritoneal cavity in the reduction of bacterial absorption and in the remainder non-phagocyted bacteria in the circulating blood of rat. METHODS: Thirty four Wistar females rats were used, distributed in the following groups: A (n=10), non-treated; B (n=9), wash of the peritoneal cavity with solution of PVI to 1% in saline solution; C (n=15), wash of the cavity with saline solution. After anesthesia, it was made intraperitoneal infusion of solution of Escherichia coli labeled with 99mTc containing 10(8) CFU/ml. After 40 minutes, it was made the treatment, in the group A, manipulation of the viscera; in the group B, irrigation of the peritoneal cavity with warm solution of 1% PVPI to 37,5 degrees C, and in the group C irrigation with warm saline (37,5 degrees C). After 15 minutes of the treatment, blood samples and fragments of liver, spleen and lung was obtained for count of the radioactivity, and animals killed by abdominal aorta section. There were determined the bacterial absorption index and the remainder index in the bloodstream. RESULTS: Of the total of bacteria infused in the peritoneum, there was absorption of 0,92% (0,14% to 2,13%) in the animals of the group A (controls), 0,49% (0,18% to 0,71%) after use of topical PVPI (group B) and 0,80% (0,04% to 3,8%) after wash with saline solution (group C). There was significant reduction of the absorption when compared the treated animals with PVPI and the controls (p=0,003). Of the total of bacteria absorbed for the circulatory current, the percentile amount of bacteria non-phagocyted in the outlying blood was of 2,9% (1,1% to 17,7%) in the control group, 15,2% (8,3% to 21,4%) in those treated with PVPI (group B) and 6,9% (0,8% to 29,7%) after wash with saline solution (group C), with difference among controls and treated with PVPI (p=0,01). CONCLUSION: The wash of the cavity peritoneal of mice with solution containing PVPI showed to be capable to reduce the absorption of bacteria by peritoneum of rat; however it seems to interfere with the function of the phagocytic cells for the observation of the increase of viable bacteria in the outlying blood of those animals.
Assuntos
Anti-Infecciosos Locais/uso terapêutico , Infecções por Escherichia coli/tratamento farmacológico , Lavagem Peritoneal , Peritonite/tratamento farmacológico , Povidona-Iodo/uso terapêutico , Animais , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Feminino , Macrófagos Peritoneais , Cavidade Peritoneal , Peritonite/microbiologia , Fagocitose , Ratos , Ratos Wistar , SoluçõesRESUMO
PURPOSE:To evaluate whether scintigraphy with technetium-99m-labeled ceftizoxime (99mTc-CFT) can differentiate mediastinitis from aseptic inflammation associated with sternotomy.METHODS:Twenty female Wistar rats were randomly distributed into four groups: S (control) -partial upper median sternotomy with no treatment; SW (control) - sternotomy and treatment of sternal wounds with bone wax; SB - sternotomy and infection with Staphylococcus aureus; SWB - sternotomy with bone wax treatment and bacterial infection. Scintigraphy with 99mTc-CFT was performed eight days after surgery and images were collected 210 and 360 min after infusion of the radiopharmaceutical.RESULTS: No animals exhibited clinical signs of wound infection at the end of the experiment, although histological data verified acute inflammatory response in those experimentally infected with bacteria. Scintigraphic images revealed that tropism of 99mTc-CFT to infected sternums was greater than to their non-infected counterparts. Mean counts of radioactivity in bacteria-infected sternal regions (SB and SWB) were significantly higher (p = 0.0007) than those of the respective controls (S and SW).CONCLUSION:Scintigraphy with technetium-99m-labeled ceftizoxime is a method that can potentially detect infection post sternotomy and differentiate from aseptic inflammation in animals experimentally inoculated with S. aureus.
Assuntos
Animais , Feminino , Ceftizoxima/análogos & derivados , Mediastinite , Compostos de Organotecnécio , Esternotomia/efeitos adversos , Esterno , Infecção da Ferida Cirúrgica , Modelos Animais de Doenças , Distribuição Aleatória , Ratos Wistar , Reprodutibilidade dos Testes , Staphylococcus aureus , Infecções Estafilocócicas , Esterno/microbiologia , Infecção da Ferida Cirúrgica/microbiologiaRESUMO
Objective: To evaluate the splenic parenchymal blood distribution through scintigraphic study. Methods: Thirty Wistar rats were randomly divided into six groups (n = 5). Group 1 (spleen - 30 minutes) and Group 2 (spleen - 90 minutes) underwent laparotomy with direction of blood flow to the spleen by ligature of the aorta near the iliac bifurcation and splanchnic vessels, keeping blood flow only in the splenic artery; Group 3 (spleen and stomach - 30 minutes) and Group 4 (spleen and stomach - 90 minutes) underwent laparotomy with direction of blood flow to the spleen and stomach by ligature of the aorta near the iliac bifurcation and splanchnic vessels, maintaining the flow through the splenic, gastric and splenogastric vessels; Group 5 (control - 30 minutes) and Group 6 (control - 90 minutes) underwent laparotomy and ligation of the aorta near the iliac bifurcation, keeping the flow to the abdominal organs. After arterial ligation, the animals received an injection of 0.2 ml of sodium pertechnetate in the aorta. Scintigraphic images were taken and the animals had their spleens removed for radioactivity counting with an automatic counter device. Results: There was no difference in the amounts of radiation from the spleen between groups, indicating retention of the radioisotope by the spleen, even after the period of 90 minutes. Conclusion: The blood flow through the spleen is not continuous. The blood diffuses through the splenic parenchyma and its venous drainage is slow, not following a predictable sequence. .
Objetivo: avaliar a distribuição sanguínea vasculoparenquimatosa do baço, por meio de estudo cintilográfico. Métodos: trinta ratos da raça Wistar foram distribuídos aleatoriamente em seis grupos (n=5). Grupo 1 (baço - 30 minutos) e Grupo 2 (baço - 90 minutos): submetidos à laparotomia com direcionamento do fluxo sanguíneo para o baço, por meio de ligadura da aorta próxima à bifurcação das ilíacas e dos vasos esplâncnicos, mantendo apenas a artéria esplênica; Grupo 3 (baço e estômago - 30 minutos) e Grupo 4 (baço e estômago - 90 minutos): submetidos à laparotomia com direcionamento do fluxo sanguíneo para baço e estômago, por meio de ligadura da aorta próxima da bifurcação das ilíacas e dos vasos esplâncnicos, com manutenção do fluxo pelas artérias esplênica, gástrica e vasos esplenogástricos; Grupo 5 (controle - 30 minutos) e Grupo 6 (controle - 90 minutos): submetidos à laparotomia e ligadura da aorta próxima à bifurcação das ilíacas, mantendo o fluxo para os órgãos abdominais. Após as ligaduras arteriais, os animais receberam injeção de 0,2ml de pertecnetato de sódio na aorta. Foram realizadas imagens cintilográficas, e os animais tiveram o baço retirado para contagem radioativa em aparelho contador automático. Resultados: não houve diferença nos valores de radiação do baço entre os grupos, indicando retenção do radioisótopo pelo baço, mesmo após o período de 90 minutos. Conclusão: o fluxo sanguíneo através do baço não é contínuo. O sangue difunde-se pelo parênquima esplênico e sua drenagem venosa é lenta, não seguindo sequência previsível. .
Assuntos
Animais , Feminino , Ratos , Fluxo Sanguíneo Regional , Baço/irrigação sanguínea , Distribuição Aleatória , Cintilografia , Ratos WistarRESUMO
PURPOSE: To evaluate the effectiveness of the use of the povidone-iodine (PVI) added to the liquid of wash of the peritoneal cavity in the reduction of bacterial absorption and in the remainder non-phagocyted bacteria in the circulating blood of rat. METHODS: Thirty four Wistar females rats were used, distributed in the following groups: A (n=10), non-treated; B (n=9), wash of the peritoneal cavity with solution of PVI to 1 percent in saline solution; C (n=15), wash of the cavity with saline solution. After anesthesia, it was made intraperitoneal infusion of solution of Escherichia coli labeled with 99mTc containing 10(8) CFU/ml. After 40 minutes, it was made the treatment, in the group A, manipulation of the viscera; in the group B, irrigation of the peritoneal cavity with warm solution of 1 percent PVPI to 37,5ºC, and in the group C irrigation with warm saline (37,5ºC). After 15 minutes of the treatment, blood samples and fragments of liver, spleen and lung was obtained for count of the radioactivity, and animals killed by abdominal aorta section. There were determined the bacterial absorption index and the remainder index in the bloodstream. RESULTS: Of the total of bacteria infused in the peritoneum, there was absorption of 0,92 percent (0,14 percent to 2,13 percent) in the animals of the group A (controls), 0,49 percent (0,18 percent to 0,71 percent) after use of topical PVPI (group B) and 0,80 percent (0,04 percent to 3,8 percent) after wash with saline solution (group C). There was significant reduction of the absorption when compared the treated animals with PVPI and the controls (p=0,003). Of the total of bacteria absorbed for the circulatory current, the percentile amount of bacteria non-phagocyted in the outlying blood was of 2,9 percent (1,1 percent to 17,7 percent) in the control group, 15,2 percent (8,3 percent to 21,4 percent) in those treated with PVPI (group B) and 6,9 percent (0,8 percent to 29,7 percent) after wash...
OBJETIVO: Avaliar a eficácia do uso do polivinilpirrolidona-iodo (PVPI) acrescido ao líquido de lavagem da cavidade peritoneal na redução da absorção bacteriana e no remanescente bacteriano não fagocitado no sangue periférico de ratos. MÉTODOS: Estudou-se 34 ratos Wistar fêmeas, distribuídos aleatoriamente nos seguintes grupos: controle (n=10), nenhum tratamento; PVPI (n=9), lavagem da cavidade peritoneal com solução de PVPI a 10 por cento em solução salina; salina (n=15), lavagem da cavidade com solução salina. Após anestesia, fez-se inoculação intraperitoneal de solução de Escherichia coli marcadas com 99mTc contendo 10(8) UFC/ml. Após 40 minutos, realizou-se o tratamento que foi, no grupo controle, manipulação das vísceras; no grupo PVPI, irrigação da cavidade peritoneal com solução de PVPI aquecido a 37,5ºC na concentração de 1 por cento, e no grupo salina irrigação com solução salina aquecida a 37,5ºC. Após 15 minutos do tratamento, os animais foram mortos por secção da aorta abdominal e colhidas amostras do sangue, do fígado, do baço e do pulmão para contagem da radioatividade. Foram determinados o índice de absorção bacteriano e o índice de remanescente no sangue periférico. RESULTADOS: Do total de bactérias inoculadas no peritôneo, houve absorção de 0,92 por cento (0,14 por cento a 2,13 por cento) nos animais do grupo controle, 0,49 por cento (0,18 por cento a 0,71 por cento) após uso do PVPI tópico e 0,80 por cento (0,04 por cento a 3,8 por cento) após lavagem com solução salina. Houve redução significativa da absorção quando comparados os animais tratados com o PVPI e os controles não tratados (p=0,03). Do total de bactérias absorvidas para a corrente circulatória, o percentual de bactérias não fagocitadas presentes no sangue periférico foi de 2,9 por cento (1,1 por cento a 17,7 por cento) nos animais controle 15,2 por cento (8,3 por cento a 21,4 por cento) naqueles tratados com PVPI e 6,9 por cento (0,8 por cento a 29,7 por...
Assuntos
Animais , Feminino , Ratos , Anti-Infecciosos Locais/uso terapêutico , Infecções por Escherichia coli/tratamento farmacológico , Lavagem Peritoneal , Peritonite/tratamento farmacológico , Povidona-Iodo/uso terapêutico , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Macrófagos Peritoneais , Cavidade Peritoneal , Fagocitose , Peritonite/microbiologia , Ratos Wistar , SoluçõesRESUMO
The aim of this work was to prepare a kit of 99mTc-ceftizoxime (99mTc-CFT), with stability and biological activity preserved, able to identify a septic focus (E. coli) in the experimental infection model in rats. The preparation of the CFT kit involved the use of lyophilized solutions containing the antibiotic ceftizoxime and the sodium dithionite reducing agent (6.0 mg/mL). After lyophilization, the kit was reconstituted with 1.0 mL of sodium 99mTc-pertechnetate solution (Na99mTcO4-) with an activity of 370 MBq. The solution was boiled for 10 min and filtered through a cellulose ester filter. The labeling efficiency was on the order of 92 percent, remaining stable for six hours and the kit remained stable for two months. The biological activity of the 99mTc-CFT was evaluated by diffusion in agar impregnated with E.coli and S. aureus. Seven Wistar rats, weighing from 200 to 250 g, were used for the development of the septic focus. After 24 hours from the induction of the infectious site (E.coli), the animals were anesthetized and 0.1 mL of 99mTc-CFT (37 MBq) was injected into the tail veins of the animals. The images were obtained with a gamma camera one, two and six hours after injection and the regions of interest (ROIs) were calculated. The diameters of the inhibition halos for 99mTc-CFT were 27.16 ± 0.23 and 27.17 ± 0.20 for S.aureus and E.coli, respectively, while those for the unlabeled CFT were 30.4 ± 0.33 and 29.43 ± 0.26, respectively. The results for the biodistribution of 99mTc-CFT in infected animals furnished a ratio of 1.97 ± 0.31, 2.10 ± 0.42 and 2.01 ± 0.42 for cpm-target/cpm-no target for the one, two and six-hour periods, respectively. The images showed a clear uptake of labeled antibiotic (99mTc-CFT) by the infectious site during the experiment. The results attest to the viability of producing a kit with 99m technetium-labeled ceftizoxime for the investigation of infectious processes.
O objetivo deste trabalho foi preparar um kit de Tc-99m Ceftizoxima (99mTc-CFT), com estabilidade e atividade biológica preservadas, capaz de identificar um foco séptico (E.coli) em um modelo experimental de infecção em ratos. A preparação do kit de CFT baseou-se em uma mistura de soluções contendo o antibiótico ceftizoxima (2,5mg/mL) e o agente redutor ditionito de sódio (6,0mg/mL) que foram submetidos a um processo de liofilização. Após a liofilização, o kit foi reconstituído with 1,0 mL de solução de pertecnetato de sódio (Na99mTcO4 -), contendo uma atividade de 370 MBq. Em seguida, a solução foi incubada, por 10 min, em banho fervente (1000C) e, posteriormente, foi resfriada em água corrente por 5 min. A eficiência de marcação foi da ordem de 92 por cento permanecendo estável por 6 horas e o kit permaneceu estável por 2 meses. A atividade biológica do 99mTc-CFT foi avaliada por difusão em ágar impregnado com E.coli e S. aureus. Foram utilizados 07 ratos Wistar, pesando entre 200 a 250 g, para o desenvolvimento do foco séptico. Após 24 horas da indução do foco infeccioso (E.coli), os animais foram anestesiados e 0,1 mL da 99mTc-CFT (37 MBq) foi injetado na veia da cauda dos animais. As imagens de 1, 2 e 6 horas após a injeção foram adquiridas em uma gama câmara e as regiões de interesse (ROIS) foram calculadas. Os valores obtidos dos diâmetros dos halos de inibição para 99mTc-CFT foram 27,16±0,23 e 27,17±0,20 para S. aureus e E.coli, respectivamente, sendo que para CFT não marcada foram 30,4±0,33 e 29,43±0,26, respectivamente. Os resultados obtidos da biodistribuição da 99mTc-CFT nos animais com focos infecciosos mostraram uma relação alvo/não alvo de 1,97±0,31, 2,10±0,42 e 2,01±0,42 para os tempos de 1, 2 e 6 horas, respectivamente. As imagens obtidas mostraram nítida captação do antibiótico marcado (99mTc-CFT) pelo foco infeccioso ao longo do experimento. Os resultados obtidos neste...
RESUMO
Infections and endotoxemia continue to be the principal causes of morbidity and mortality of patients with obstructions of the bile duct. The objective of the present work was the investigation of the phagocitary capacity of the mononuclear system in an experimental model of obstructive jaundice utilizing Tc-99m E.coli. The levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) were significantly higher in jaundiced rats than in the control animals (p < 0.001). The liver of the jaundiced animals presented a significant reduction in Tc-99m E.coli uptake when compared to the controls (p < 0.001). The data also showed that there was a significant increase in the uptake of Tc-99m E.coli by the lungs of jaundiced rats (p < 0.01). The histological analyses of the liver of jaundiced rats showed an intense and diffuse proliferation of the bile ducts and an intensified polyploidy of the hepatocytes (mean volume = 843 µm³), but no significant alterations were observed in the lungs of either group. This dates could contribute to a better understanding of the mechanisms involved in cases of bacteremia, renal failure and pulmonary dysfunction observed in clinical analyses of obstructive jaundice.
Nos pacientes com obstrução do ducto biliar, as infecções e a endotoxemia continuam sendo uma das principais causas de morbidade e mortalidade. O objetivo desse trabalho foi investigar a capacidade fagocitária do sistema mononuclear, em um modelo experimental de icterícia obstrutiva, utilizando Tc-99m E.coli. Os níveis de aspartato aminotransferase (AST), alanina aminotransferase (ALT) e fosfatase alcalina (PAL) nos ratos com ligadura do ducto biliar comum (CBD) encontram-se significativamente mais elevados do que nos ratos sham. (p < 0.001). O fígado dos animais ictéricos apresentou uma significativa redução na captação da Tc-99m E.coli quando comparado com o controle. Os dados mostraram também, que houve um aumento significativo na captação da Tc-99m E.coli pelo pulmão dos ratos ictéricos (p < 0.01). O exame histológico dos cortes de fígado dos animais ictéricos apresentou proliferação intensa e difusa dos ductos biliares e uma acentuada poliploidia dos hepatócitos (volume médio: 843 µm³), Não foram observadas alterações significativas nos pulmões de nenhum grupo.
RESUMO
In obstructive jaundice, the passage of bacteria and endotoxins through the intestine wall to reach the systemic circulation is associated with septicemia, renal failure and pulmonary dysfunction. The aim of this work was to investigate bacterial translocation utilizing 99mTc-E.coli in an experimental model of obstructive jaundice. The levels of bilirubin in rats that were subjected to ligature of the bile duct were significantly increased when compared to control animals (p < 0.001). The biodistribution results did not show any translocation of 99mTc-E.coli to the mesenteric lymphatic nodules, liver, spleen or lungs of the rats that suffered ligature of the bile duct (p > 0.05). The evaluation of the intestinal permeability using "per os" administration of 99mTc-DTPA showed 1.61 ± 0.57 percent and 1.39 ± 0.72 percent of radioactivity in the urine of the control and jaundice animals, respectively. The histological analysis of the distal wall of the ileum showed that the covering epithelium and the crypt were morphologically preserved in both groups. The seven-day period after the ligature of the bile duct may not have been long enough to promote modifications in intestinal wall to occur so as to permit the passage of Tc-99m E.coli.
Na icterícia obstrutiva, a passagem de bactérias e endotoxinas através da parede intestinal alcançando a circulação sistêmica está associada com septicemia, falência renal e disfunção pulmonar. A proposta deste trabalho foi investigar a translocação bacteriana, empregando a Tc-99m E.coli, em um modelo experimental de icterícia obstrutiva. Os níveis de bilirrubina nos ratos que sofreram a ligadura do ducto biliar estavam significativamente aumentados quando comparados com os valores dos animais controles (p<0,001). Os resultados de biodistribuição não mostraram translocação da Tc-99m E.coli para os nódulos linfáticos mesentéricos, fígado, baço e pulmões dos ratos que sofreram ligadura do ducto biliar (p>0,05). A avaliação da permeabilidade intestinal usando a administração "per os" de 99mTc-DTPA mostrou um percentual de eliminação deste radiofármaco na urina de 1,61±0,57 e 1,39±0,72 para os animais controles e ictéricos, respectivamente. A análise histológica da parede distal do íleo mostrou que tanto o epitélio de revestimento quanto as criptas apresentaram morfologicamente conservados em ambos os grupos. O tempo transcorrido, 7 dias, após a ligadura do ducto biliar talvez não tenha sido longo o suficiente para promover modificações na parede intestinal de modo a permitir a passagem da 99mTc-E.coli.
RESUMO
The oral administration of proteic antigens, like ovalbumin, may result in the induction of oral tolerance or immunization. The aim of this work was to label a protein antigen with 99mTechnetium, encapsulate it in liposomes and investigate its absorption and tissue distribution after oral administration in mice. Ovalbumin was labeled with 99mTechnetium and encapsulated in small unilamellar vesicles. 99mTc-OVA encapsulated or not in liposomes was administrated to mice that were sacrificed after different times. The radioactivity was measured in various organs of the animals. Differences concerning the biodistribution of 99mTc-OVA were noticed. The technique may represent alternatives for the induction of immunization or oral tolerance.
A administração oral de antígenos protéicos pode levar a indução ou supressão da resposta imune. A indução da resposta imune é de grande importância para o desenvolvimento de vacinas orais. Já a supressão, denominada de tolerância oral, pode vir a representar uma solução terapêutica a numerosas enfermidades. O objetivo deste trabalho foi de compreender o comportamento in vivo de um antígeno modelo, a ovalbumina (OVA), marcado com um radioisótopo, o 99m tecnécio (99mTc), e administrado por via oral na sua forma livre e encapsulado em lipossomas de pequeno tamanho (SUV). As amostras foram administradas por gavagem à camundongos, sacrificados após 30, 60, 90, 120, 180 e 360 minutos. A radioatividade foi medida no estômago, intestinos, placas de Peyer, linfonodos mesentéricos, baço, fígado e sangue dos animais. Os resultados mostraram que a OVA livre ou encapsulada em lipossomas SUV apresenta biodistribuições distintas. As diferenças encontradas na biodistribuição da OVA livre ou encapsulada podem representar mecanismos diferentes para a indução ou não de tolerância oral.
RESUMO
OBJETIVOS: Para se evitar o estado asplênico, muitas medidas preservadoras do baço têm sido propostas na literatura, como a esplenorrafia, a esplenectomia parcial com preservação dos vasos hilares e o auto-implante de tecido esplênico. A esplenectomia subtotal, com conservação do pólo superior do baço, nutrido apenas pelos vasos esplenogástricos é uma alternativa quando o pedículo esplênico precisa ser ligado. O objetivo deste estudo foi avaliar a influência das esplenectomias parcial, subtotal e total na distribuição da Escherichia coli no sistema mononuclear fagocitário. MÉTODO: Foram estudados 32 ratos divididos em 4 grupos: operação simulada (mantendo todo o baço), esplenectomia parcial, esplenectomia subtotal e esplenectomia total. Após cinco semanas da operação, uma alíquota de Escherichia coli marcada com 99m-tecnécio foi injetada por via venosa. Após 20 minutos, os animais foram mortos, e o baço, os pulmões e o fígado foram retirados para se verificar a distribuição das bactérias marcadas. RESULTADOS: A quantidade de Escherichia coli no tecido esplênico foi maior no grupo com o baço íntegro em comparação com os grupos esplenectomia parcial e subtotal. A distribuição da bactéria marcada pelo baço não diferiu nos grupos com esplenectomia parcial ou subtotal. A quantidade de bactérias no pulmão foi maior no grupo esplenectomia parcial do que a do grupo com esplenectomia subtotal. Após esplenectomia subtotal, a distribuição da bactéria marcada foi maior no fígado em comparação com a captação desse órgão nos demais grupos. CONCLUSÕES: O pólo superior do baço, suprido apenas pelos vasos esplenogástricos, tem capacidade de remover da circulação bactérias vivas, mostrando que, mesmo sem a vascularização pelo pedículo esplênico, há uma eficiente depuração sangüínea. A distribuição da Escherichia coli pelo sistema mononuclear fagocitário apresenta comportamentos diferentes, dependendo do tipo de esplenectomia a que o animal é submetido.
BACKGROUND: To avoid asplenic state, many approaches preserving the spleen have been proposed, such as splenorraphy, partial splenectomy with hilum vessels preservation and autotransplantation. Subtotal splenectomy preserving the upper splenic pole supplied only by splenogastric vessels, is an alternative when splenic pedicle cannot be maintained. The purpose of this study is to evaluate the influence of partial, subtotal and total splenectomy on Escherichia coli distribution in mononuclear phagocyte system. METHODS: Thirty-two rats were divided into the following 4 groups: sham operation (no splenectomy), partial splenectomy, subtotal splenectomy and total splenectomy. In the fifth week postoperative, an aliquot of Escherichia coli labelled with technetium-99m was intravenously injected. After 20 minutes, the animals were killed to remove spleen, lungs and liver, in order to verify the labelled bacteria distribution. RESULTS: The amount of Escherichia coli in the splenic tissue was greater in the group with intact spleen. The bacteria uptake by the spleen was not different from partial or subtotal splenectomy groups. The amount of bacteria in the lungs was greater in the partial splenectomy group than in the subtotal group. After subtotal splenectomy, the distribution of labelled bacteria was greater in the liver than in the others all groups. CONCLUSIONS: The upper splenic pole, supplied only by splenogastric vessels, is able to remove alive bacteria from the blood stream, showing that, even in absence of splenic pedicle, blood clearance continues to be effective. The distribution of Escherichia coli in mononuclear phagocyte system shows different behaviors, depending on the type of splenectomy.