Influence of biomaterials on scintigraphic diagnosis of periprosthetic infections. Ceftizoxime-99m technetium model

Purpose: To compare the influence of two metallic implants in the diagnosis of periprosthetic infection using 99m technetium-labeled ceftizoxime.Methods: Twenty rats were randomly divided into four groups, which received sterile and contaminated titanium and stainless steel implants. After 3 weeks, scintilographic images were obtained using a gamma chamber. Radioactivity counts were obtained for the region of interest (ROI) on the operated and non-operated paws.Results: Groups A, B, and C showed homogenous distribution of the radiopharmaceutical. Hyper uptake was observed in the operated paw from group D. The ROI target count was higher in the two groups with stainless steel implants. Among the control groups, the count was higher in the stainless steel group. Furthermore, among the contaminated groups, the uptake was higher in the stainless steel group, with a significant difference. The target: non-target ratio was significantly lower in the control and contaminated groups with both titanium and stainless steel, but the comparison between control groups and contaminated groups was only significant in the former. The cpm/g observed after a decay of 48h showed statistically significant differences between groups.Conclusion: Different biomaterials used in implants have an influence on the results of scintigraphy with 99mTc-CFT.(AU)

Scintigraphic imaging with technetium-99M-labelled ceftizoxime is a reliable technique for the diagnosis of deep sternal wound infection in rats

To evaluate whether scintigraphy with technetium-99m-labeled ceftizoxime (99mTc-CFT) can differentiate mediastinitis from aseptic inflammation associated with sternotomy. 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. 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). 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.(AU)

Study of hepatocellular function in the murine model following hepatic artery selective clamping

PURPOSE: To investigate the impact of selective hepatic artery clamping (SHAC) in hepatocellular function. METHODS: Three groups of Wistar male rats were subjected to SHAC ischemia period of 60min: Group A continuous SHAC were subjected to SHAC ischemia period of 60min, Group B intermittent SHAC of 30min with 5min of reperfusion and Group C intermittent SHAC of 15min with 5min of reperfusion. Animals without SHAC were included-Group D. To evaluate hepatocellular function blood markers and hepatic extraction function (HEF) using 99mTc-mebrofenin were performed before and after surgery. Flow cytometry was used to analyze oxidative stress and cell viability. RESULTS: A mortality rate of 7.6% in Group A was observed. HEF maintained normal values between the groups. Flow cytometry demonstrated no significant differences between the groups in viability, type of cell death as well as in the production of reactive oxygen species. CONCLUSIONS: The selective hepatic artery clamping compared to other clamping techniques results on increased cell viability and decreased hepatocyte death. The SHAC is a potential alternative to decrease per-operative bleeding while maintaining hepatocellular function.(AU)

Postnatal evaluation of intrauterine hydronephrosis due to ureteropelvic junction obstruction / Avaliação pós-natal de hidronefrose intra-uterina por estenose da junção ureteropiélica

PURPOSE: Fetal hydronephrosis is a frequent finding due to advances in prenatal ultrasonography. The definition of fetal and neonatal urinary tract obstruction is a very difficult task requiring confirmation of reduced renal function and hydronephrosis. In this study we followed a series of consecutive patients with intrauterine hydronephrosis that persisted during post-natal life. METHODS: 116 newborns with antenatal hydronephrosis diagnosed by ultrasound and submitted to a specific post-natal evaluative protocol with a follow-up period of 6 years. RESULTS: In 45 (38.8%) of 116 patients, ureteropelvic junction (UPJ) obstruction was confirmed and surgical correction of the UPJ obstruction was done in 19 patients. From 26 children who were initially submitted to non-surgical treatment, only 6 (23%) needed a surgical approach during follow up. Overall analysis showed that surgery was performed in 25 patients with UPJ obstruction, and the others 20 patients were kept under clinical observation, since normal renal function was confirmed by scintigraphy scans. CONCLUSION: Fetal hydronephrosis due to UPJ obstruction deserves careful postnatal evaluation. UPJ obstruction is the most frequent anomaly and its surgical treatment has very precise indications. The evaluative protocol was useful in identify patients that could be followed-up with a non-surgical approach.(AU)

OBJETIVO: Com a ampla utilização dos exames ultrassonográficos na avaliação pré-natal, é frequente o diagnóstico da hidronefrose fetal. A definição de obstrução do trato urinário no periodo pós-natal necessita da confirmação de redução da função renal além da hidronefrose. Neste estudo, acompanhamos uma série de pacientes consecutivos com hidronefrose intra-útero que persistiu no periodo pós-natal. MÉTODOS: 116 recém-nascidos com hidronefrose pré-natal diagnosticada pela ultrassonografia foram submetidos a protocolo específico de avaliação e companhados pelo periodo de 06 anos. RESULTADOS: Em 46 (38,8%) dos 116 pacientes foi confirmado o diagnóstico de estenose da junção ureteropiélica (JUP). Conforme os resultados do protocolo aplicado a correção cirúrgica da estenose da JUP foi realizada em 19 pacientes. Das 26 crianças encaminhadas inicialmente para observação clínica, apenas 6 (23%) necessitaram cirurgia durante o seguimento ambulatorial. Na análise geral, o procedimento cirúrgico para correção da estenose da JUP foi indicado em 25 pacientes. Nas outras 20 crianças não houve necessidade da realização da cirurgia. CONCLUSÃO: a hidronefrose fetal requer cuidadosa avaliação pós-natal. A estenose da junção pielo-ureteral é a anomalia mais frequente como causa da hidronefrose, e sua correção cirúrgica tem indicações precisas. O protocolo aplicado foi útil em diferenciar pacientes que não necessitaram cirurgia para tratamento da estenose da JUP.(AU)

Long-term following-up of viability of spleen autotransplants in the Beagle canine model / Avaliação em longo prazo da viabilidade do autotransplante de baço em cães Beagle

PURPOSE: To examine the possible late complications of splenectomy or spleen autotransplantation in large laboratory animal model, in which we need non-invasive or minimal-invasive methods for long-term monitoring of the experimental animals. METHODS: Experimental groups of beagle dogs were: non-operated control, sham-operated control, splenectomy, spleen autotransplantation with 5 or 10 spleen-chips taken into the greater omentum (Furka's technique). Prior to operations, on the 1st postoperative week, monthly till the 6th as well as in the 9th and 12th month, hemorheological examinations were performed. In postoperative 12th month colloid scintigraphy and diagnostic laparoscopy were carried out. At the end of the investigation comparative morphological examinations were performed, too. RESULTS: From the 4th-5th postoperative month filtration function of spleen-autotransplants showed particular restoration compared to splenectomy group. However, the functional results did not reach the values of the control or sham-operated groups. Sham-operated control's scintigraphy nicely showed activity in the spleen. In spleen autotransplantation-groups scintigraphy indicated well the activity of spleen-chips. During diagnostic laparoscopy spleen-chips with their blood supply were found. Histologically, the structure of spleen­autotransplants was similar to normal splenic tissue. CONCLUSIONS: The autotransplants are regenerated, their functions have been partly restored, and thus spleen autotransplantation may prevent the possible complications of splenectomy. These parameters and the presented investigative protocol are suitable for long-term following-up of viability of the spleen-autotransplants.(AU)

OBJETIVO: Examinar as possíveis complicações tardias da esplenectomia ou do autotransplante de baço em modelo animal de grande porte, no qual faz-se necessário o uso de métodos não invasivos ou minimamente invasivos para monitorizar os animais de experimentação. MÉTODOS: Grupos experimentais de cães beagle foram: não-operados controle, sham-operados controle, esplenectomia, autotransplante de baço com 5 ou 10 fatias de baço colocados no grande omento (técnica de Furka). Antes das operações, na 1ª semana de pós­operatório, mensalmente até 6o.assim como no 9º. e 12º. mês, foram realizados exames hemorreológicos. No 12º. mês de pós-operatório, cintilografia colóide e laparoscopia diagnóstica foram realizadas. Ao final do experimento, exames morfológicos comparativos foram realizados também. RESULTADOS: A partir do 4º-5º mês pós-operatório, a função de filtração dos baços autotransplantados mostraram particular restauração comparados ao grupo esplenectomia. Entretanto, os resultados funcionais não alcançaram os valores dos grupos controle ou sham-operados. A cintilografia dos controles sham-operados mostraram atividade no baço. Nos grupos de autotransplante, a cintilografia indicou bem a atividade das fatias de baço. Durante a laparoscopia diagnóstica, as fatias de baço com seu suprimento sanguíneo foram encontrados. Histologicamente, a estrutura dos autotransplantes de baço foi similar ao tecido normal de baço. CONCLUSÕES: Os autotransplantes são regenerados, suas funções foram parcialmente restauradas, e então ao autotransplantate esplênico pode prevenir as possíveis complicações da esplenectomia. Estes parâmetros e o protocolo experimental são adequados para o seguimento em longo prazo da viabilidade de autotransplantes esplênicos.(AU)

A novel model of distal colon cancer in athymic mice / Novo modelo de câncer de cólon distal em camundongos atímicos

PURPOSE: The present a novel adenocarcinoma model in athymic mice. METHODS: Seven athymic mice were used. Colon diversion and distal fistula were made. Adenocarcinoma cells were inoculated in the submucosa of fistula. Tumor growth was monitored daily. Scintigraphy with 99mTc-MIBI was performed to identify the tumor. RESULTS: The model of distal colon cancer is feasible. Tumor detection was possible by both, macroscopically and molecular imaging. All resections demonstrated poorly differentiated tumors. Colon obstruction occurred in one case, similarly to evolution in human tumors of distal colon. CONCLUSION: The proposed model of distal colon cancer is feasible, allows for easy monitoring of tumoral growth by both, macroscopically and molecular imaging, and is suitable for studying the evolution of tumor with implementation of cytotoxic therapy in vivo.(AU)

OBJETIVO: Apresentar novo modelo de adenocarcinoma distal em camundongos atímicos. MÉTODOS: Foram utilizados sete camundongos atímicos. Desvio do cólon distal e fístula foram feitas. Células de adenocarcinoma foram inoculadas na submucosa da fístula. O crescimento do tumor foi monitorado diariamente. Cintilografia com 99mTc-MIBI foi realizada para identificar o tumor. RESULTADOS: O modelo de câncer de cólon distal é viável. Detecção do tumor foi possível macroscopicamente e por imagem molecular. Todas as ressecções demonstraram tumores pouco diferenciados. Obstrução do cólon ocorreu em um caso, de forma semelhante à evolução em tumores humanos do cólon distal. CONCLUSÃO: O modelo de câncer do cólon distal proposto é viável, permite a monitorização fácil do crescimento tumoral macroscopicamente e por imagem molecular, sendo adequado para o estudo da evolução de tumor com aplicação de terapia citotóxica in vivo.(AU)

Neovascularization after ischemic injury: evaluation with 99mTc-HYNIC-RGD / Neovascularizacao apos lesao isquemica: avaliacao com 99mTc-HYNIC-RGD

Purpose: Angiogenesis involves many mediators including integrins, and the tripeptide RGD is a target amino acid recognition sequence for many of them. Hindlimb ischemia is a simple and convenient animal model however standardization of the injection procedures in the devascularized and control limb is lacking, thus rendering difficult the interpretation of results. The aim of this investigations was to evaluate neovascularization in a hindlimb murine model by means of 99mTc-HYNIC-ß-Ala-RGD. Methods: 99mTc-HYNIC-RGD analog was prepared using coligands. Ischemia was induced in Wistar rats by double- ligation of the common femoral artery. Radiolabeled RGD was injected after 2h, as well as 1, 3, 5, 7, 10 and 14 days. Uptake was evaluated by planar imaging and biodistribution studies. Results: The highest ratio between ischemia and control was achieved at the 7th day (2.62 ± 0.95), with substantial decrease by the 14th day. For pertechnetate the 7th day ratio was 0.87 ± 0.23. Scintigraphic image confirmed different uptakes. Conclusion: 99mTc-HYNIC-RGD analog concentrated in ischemic tissue by the time of widespread angiogenesis and pertechnetate confirmed reduction in blood flow. In this sense, the protocol can be recommended for ischemic models. (AU)

Objetivo: A angiogênese em resposta a fenômenos isquêmicos envolve vários mediadores como as integrinas, sendo que o tripeptídeo RGD possui uma seqüência de aminoácidos com reconhecimento para este alvo. O modelo animal de isquemia de pata traseira é simples e conveniente, porém não há uma padronização do procedimento de injeção e controle radioisotópico em membro desvascularizado, dificultando, portanto a interpretação de resultados. O objetivo deste estudo foi avaliar a neovascularização em modelo murino de isquemia de pata traseira através do radiotraçador 99mTc-HYNIC-ß-Ala-RGD. Métodos: O análogo 99mTc-HYNIC-RGD foi preparado usando coligantes. A isquemia foi induzida em ratos Wistar por dupla-ligação da artéria femoral comum na prega inguinal. Peptídeo RGD radiomarcado foi injetado após 2h, assim como 1, 3, 5, 7, 10 e 14 dias. A captação foi avaliada por imagem planar e estudos de biodistribuição. Resultados: A maior diferença de captação entre isquemia e pata controle foi obtida no 7o dia (2,62 ± 0,95), com decréscimo acentuado no 14o dia. Para o pertecnetato a razão no 7o dia foi 0,87 ± 0,23. A imagem cintilográfica confirmou as diferentes captações. Conclusões: O análogo 99mTc-HYNIC-RGD concentrou-se no tecido isquêmico na etapa em que a angiogênese é mais acentuada, e o estudo do pertecnetato confirmou a redução no fluxo sanguíneo. Desta maneira, este protocolo diagnóstico pode ser recomendado para modelos isquêmicos. (AU)

Effect of sildenafil in renal ischemia/reperfusion injury in rats / Efeito do sildenafil na lesão renal por isquemia/reperfusão em ratos

PURPOSE: To evaluate the effect of sildenafil, administered prior to renal ischemia/reperfusion (I/R), by scintigraphy and histopathological evaluation in rats. METHODS: Twenty-four rats were divided randomly into two groups. They received 0.1 ml of 99mTechnetium-etilenodicisteine intravenous, and a baseline (initial) renal scintigraphy was performed. The rats underwent 60 minutes of ischemia by left renal artery clamping. The right kidney was not manipulated. The sildenafil group (n=12) received orally 1 mg/kg of sildenafil suspension 60 minutes before ischemia. Treatment with saline 0.9 percent in the control group (n=12). Half of the rats was assessed after 24 hours and half after seven days I/R, with new renal scintigraphy to study differential function. After euthanasia, kidneys were removed and subjected to histopathological examination. For statistical evaluation, Student t and Mann-Whitney tests were used. RESULTS: In the control group rats, the left kidneys had significant functional deficit, seven days after I/R, whose scintigraphic pattern was consistent with acute tubular necrosis, compared with the initial scintigraphy (p<0.05). Sildenafil treatment resulted in better differential function of the left kidneys 24h after reperfusion, compared with controls. Histopathologically, the left kidney of control rats (24 hours after I/R) showed a higher degree of cellular necrosis when compared with the sildenafil treated rats (p<0.05). CONCLUSION: Sildenafil had a protective effect in rat kidneys subjected to normothermic I/R, demonstrated by scintigraphy and histomorphometry.(AU)

OBJETIVO: Estudar o efeito do sildenafil, administrado previamente à isquemia/reperfusão (I/R) renal, em avaliações cintilográficas e histopatológicas em ratos. MÉTODOS: Vinte e quatro ratos Wistar foram aleatoriamente distribuídos em dois grupos. Os animais receberam 0,1 ml IV de 99mTecnécio-Etilenodicisteína, foram submetidos à cintilografia renal inicial e em seguida submetidos a isquemia no rim esquerdo, com oclusão da artéria renal, durante 60 minutos, com posterior reperfusão. O grupo sildenafil (n=12) recebeu previamente 1mg/kg de sildenafil em suspensão 60 minutos antes da isquemia. Solução salina 0,9 por cento foi administrada no grupo controle (n=12). Metade dos animais de cada grupo foi avaliada após 24 horas e a outra metade após sete dias de reperfusão, com nova cintilografia renal. Após eutanásia, os rins foram retirados e submetidos a exame histopatológico. Na avaliação estatística foram empregados os testes t de Student e de Mann-Whitney. RESULTADOS: Foi observado no rim esquerdo (submetido a I/R) do grupo controle déficit funcional diferencial nas imagens cintilográficas após sete dias, com padrão de necrose tubular aguda, quando comparado com a cintilografia inicial (p<0,05). O tratamento com sildenafil resultou em melhor função diferencial do rim esquerdo 24h após reperfusão, comparado com os controles. Na histopatologia, os rins esquerdos dos animais do grupo controle (24 horas pós-I/R), apresentaram maior grau de necrose celular quando comparados com o grupo tratado com o sildenafil (p<0,05). CONCLUSÃO: O sildenafil teve efeito protetor em rins de ratos submetidos à isquemia/reperfusão normotérmica, demonstrado por cintilografia e histomorfometria.(AU)

Schistosomiasis haematobia in Brazilian patients: clinical and renal functional evaluation with 99mTc-DTPA

The present study was carried out at the Army Central Hospital, Rio de Janeiro, Brazil, from September 2000 to December 2001, employing diethylenetriamine penta-acetic acid labeled with technetium-99m (99mTc-DTPA) to evaluate the renal function of nineteen symptomatic patients infected with S. haematobium during a peace mission in Mozambique. Results evidenced that the most frequent clinical manifestations were hematuria (68.4 percent) and low back pain (68.4 percent) and 73.7 percent patients had altered dynamic renal scintigraphy expressed by an increase in the excretory phase independently of the symptoms duration; furthermore, none of them had mechanical obstructive pattern. Schistosoma haematobium glomerulopathy could be considered a pathological finding without correlation with the disease clinical manifestations.(AU)

Schistosomiasis haematobia in Brazilian patients: clinical and renal functional evaluation with 99mTc-DTPA

The present study was carried out at the Army Central Hospital, Rio de Janeiro, Brazil, from September 2000 to December 2001, employing diethylenetriamine penta-acetic acid labeled with technetium-99m (99mTc-DTPA) to evaluate the renal function of nineteen symptomatic patients infected with S. haematobium during a peace mission in Mozambique. Results evidenced that the most frequent clinical manifestations were hematuria (68.4%) and low back pain (68.4%) and 73.7% patients had altered dynamic renal scintigraphy expressed by an increase in the excretory phase independently of the symptoms duration; furthermore, none of them had mechanical obstructive pattern. Schistosoma haematobium glomerulopathy could be considered a pathological finding without correlation with the disease clinical manifestations.