Testing of a new prototype surgical stapler that automates the rollover sleeve technique for venous anastomoses.

The creation of successful vascular anastomoses is of primary importance in many surgical fields. Numerous attempts to automate this process have been made. These techniques have slowly gained acceptance, but their use is still limited. This report details feasibility testing of a new prototype stapler that automates the rollover sleeve technique for venous vascular anastomoses. Male and female mongrel dogs (n=7) (25-32 kg) were used. A segment of the right (n=5) or left (n=2) iliac vein was harvested for interposition grafts after the contra lateral side was transected. In each dog, two end-to-end venous anastomoses at the interposition grafts were performed. The standard anastomosis employed continuous mattress sutures. The experimental anastomosis was performed with a new prototype surgical stapler. The stapled anastomosis was proximal and the sutured was distal. In all experiments, it was possible to perform the experimental anastomosis with the stapler. Complications included two small leaks, one due to misfiring of a single pin in one experimental site. These leaks required suture reinforcement. One dog died of hemorrhage due to a slipped suture at the vein harvest site. One vein had thrombus seen at the sutured site although no technical abnormalities at either of the anastomoses could be found. After two weeks, grafts were inspected grossly and histologically. Healing appeared normal. There was a trend for less inflammatory cells infiltrating stapled sites; however, this was not statistically significant. The experiments demonstrate that this device can automate the rollover sleeve technique for venous anastomoses.

Testing of a new prototype surgical stapler that automates the rollover sleeve technique for venous anastomoses

The creation of successful vascular anastomoses is of primary importance in many surgical fields. Numerous attempts to automate this process have been made. These techniques have slowly gained acceptance, but their use is still limited. This report details feasibility testing of a new prototype stapler that automates the rollover sleeve technique for venous vascular anastomoses. Male and female mongrel dogs (n=7) (25-32 kg) were used. A segment of the right (n=5) or left (n=2) iliac vein was harvested for interposition grafts after the contra lateral side was transected. In each dog, two end-to-end venous anastomoses at the interposition grafts were performed. The standard anastomosis employed continuous mattress sutures. The experimental anastomosis was performed with a new prototype surgical stapler. The stapled anastomosis was proximal and the sutured was distal. In all experiments, it was possible to perform the experimental anastomosis with the stapler. Complications included two small leaks, one due to misfiring of a single pin in one experimental site. These leaks required suture reinforcement. One dog died of hemorrhage due to a slipped suture at the vein harvest site. One vein had thrombus seen at the sutured site although no technical abnormalities at either of the anastomoses could be found. After two weeks, grafts were inspected grossly and histologically. Healing appeared normal. There was a trend for less inflammatory cells infiltrating stapled sites; however, this was not statistically significant. The experiments demonstrate that this device can automate the rollover sleeve technique for venous anastomoses.

Factors affecting hemodynamic changes after reperfusion in liver transplantation

Background: The aim this retrospective study was to determine if the duration of cold ans warm ischemia times is related to the extent of these disturbances and also to identify other factores related to recipient's condition which may affect the severity of post reperfusion syndrome. Patients and methods: The authors studied the factors affecting hemodynamic changes after reperfusion in sixty-one patients submitted to liver transplantation at the University of Miami (Jackson Memorial Hospital) during the investigation period (August 1998-january 1999). The hemodynamic parameters monitored were heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), mean pulmonary arterial pressure (MPAP), venous oxygen saturation (SVO2) and ASA status. All parameters were evaluted in three specific times: after skin incision (baseline, T1), 10 min. before reperfusion (T2), and 10 min. after reperfusion (T3). The statistical analyses were t-test for independent samples and ANOVA test. Results: All parameters changed significantly (p<0.0001) at T1 T2 and T3. No correlation was found between cold warm ischemia times and any of hemodynamic in our study and no correlation was found between gender and those parameters . Age was significantly correlated with the MAP at T2. MAP was decreased in older patients at T2. HR, MAP, CVP, PAP and CVO2 were significantly correlated with ASA classification (p<0,000033). Conclusions: No significant effects of cold and warm ischemia times on the hemodynamic intraoperative condition of the ILT were found. Furthermore, patients with a high ASA status were shown to b e at an increased risk of cardiovascular collapse after reperfusion

Graft versus host disease in a rat small bowel transplant model after T-cell depleted donor specific bone marrow infusion

Low cytoreductive regimen of irradiation associated to unmodified bone marrow infusion (UBM) does not prevent the occurrence of graft versus host disease (GVHD) after transplant. PURPOSE: In this study we evaluated the potential advantages of a long-term immunossupression and T-cell depleted bone marrow infusion (TCDBMI) in preventing the occurrence of GVHD after small bowel transplantation (SBTx). METHODS: Heterotopic SBTX was performed with Lewis rats as recipients and DA as donors and distributed into 5 groups according to the irradiation, duration of immunossupression and the use of UBM or TCDBMI: G1 (n=6), without irradiation and G2 (n=9), G3 (n=4), G4 (n=5) and G5 (n=6) was given 250 rd of irradiation. Groups 1,2,4 and G3 and 5 were infused with 100 x 106 UBM and TCDBM respectively. Animals in G1, 2, 3 were immunossupressed with 1mg/ FK506/Kg/IM for 5 days and G4 and G5 for 15 days. Anti CD3 monoclonal antibodies and immunomagnetic beads were used for T-cell depletion.Animals were examined for rejection, GVHD, chimerism characterization and ileal and skin biopsies. RESULTS: Minimal to mild rejection was observed in all groups; however, GVHD were present only in irradiated groups. Long-term immunossupression changed the severity of GVHD in G4 and G5. Rejection was the cause of death in G1 while GVHD in G2, 3, 4 and 5, not avoided by the use of TCDBMI. Total chimerism and T-cell chimerism was statistically higher in irradiated groups when compared to G1. CONCLUSION: Extended immunossupression associated to low dose of irradiation decrease the severity of GVHD, not avoided by the use of TCDBMI.

Graft versus host disease in a rat small bowel transplant model after T-cell depleted donor specific bone marrow infusion

Low cytoreductive regimen of irradiation associated to unmodified bone marrow infusion (UBM) does not prevent the occurrence of graft versus host disease (GVHD) after transplant. PURPOSE: In this study we evaluated the potential advantages of a long-term immunossupression and T-cell depleted bone marrow infusion (TCDBMI) in preventing the occurrence of GVHD after small bowel transplantation (SBTx). METHODS: Heterotopic SBTX was performed with Lewis rats as recipients and DA as donors and distributed into 5 groups according to the irradiation, duration of immunossupression and the use of UBM or TCDBMI: G1 (n=6), without irradiation and G2 (n=9), G3 (n=4), G4 (n=5) and G5 (n=6) was given 250 rd of irradiation. Groups 1,2,4 and G3 and 5 were infused with 100 x 10(6) UBM and TCDBM respectively. Animals in G1, 2, 3 were immunossupressed with 1mg/ FK506/Kg/IM for 5 days and G4 and G5 for 15 days. Anti CD3 monoclonal antibodies and immunomagnetic beads were used for T-cell depletion.Animals were examined for rejection, GVHD, chimerism characterization and ileal and skin biopsies. RESULTS: Minimal to mild rejection was observed in all groups; however, GVHD were present only in irradiated groups. Long-term immunossupression changed the severity of GVHD in G4 and G5. Rejection was the cause of death in G1 while GVHD in G2, 3, 4 and 5, not avoided by the use of TCDBMI. Total chimerism and T-cell chimerism was statistically higher in irradiated groups when compared to G1. CONCLUSION: Extended immunossupression associated to low dose of irradiation decrease the severity of GVHD, not avoided by the use of TCDBMI.

Baixas doses de irradiação associadas à infusão de células da medula óssea não previnem a ocorrência da reação do enxerto versus hospedeiro após o transplante intestinal. OBJETIVO: Neste estudo foi avaliado a potencial vantagem em estender o regime imunossupressor associado a infusão de células de medula óssea do doador depletadas de células T na prevenção da reação do enxerto versus hospedeiro após o transplante intestinal. MÉTODOS: Transplante heterotópico de intestino delgado foi realizado em ratos Lewis como receptores e DA como doadores, distribuídos em cinco grupos de acordo com a duração da imunossupressão, irradiação e do uso de medula óssea normal ou depletada: G1 (n=6), sem irradiação e G2 (n=9), G3 (n=4), G4 (n=5) e G5 (n=6) foram irradiados com 250 rd. Grupos1, 2, 4 e G3 e 5 foram infundidos com 100 x 10(6) células da medula normal e depletada respectivamente. Animais no G1,2,3 foram imunossuprimidos com 1mg/kg/FK506/ IM por cinco dias e G4 e cinco por 15 dias. Anticorpos monoclonais contra células CD3 e colunas magnéticas foram utilizadas para a depleção da medula óssea. Os animais foram examinados para a presença de rejeição, reação do enxerto versus hospedeiro, chimerismo e biópsias intestinais e da pele. RESULTADOS: Rejeição mínima foi observada em todos os grupos; entretanto, a reação do enxerto versus hospedeiro somente nos animais irradiados. Extensão da imunossupressão alterou a gravidade da reação nos animais dos G4 e 5. Rejeição foi a causa mortis no G1 e a reação do enxerto versus hospedeiro nos Grupos 2,3,4 e 5, não controlada com a infusão de medula óssea depletada. O chimerismo total e de células T do doador foi estatisticamente maior nos grupos irradiados em comparação ao G1. CONCLUSÃO: A extensão do regime de imunossupressão associado a baixas doses de irradiação diminui a gravidade da reação do enxerto versus hospedeiro, não abolida pelo uso de medula óssea depletada.

Chimerism induction by nonmyeloablactive preconditioning and bone marrow infusion in rat small bowel transplantation

In our previous work we demonstrated that the use of donor specific bone marrow infusions ( DSBMI ) after small bowel transplantation did not improve the graft survival after a short course of immunossupression. PURPOSE: In the current study, we evaluated whether recipient preconditioning with different regimens of radiation combined with DSBMI may enhance small bowel allograft survival with minimum recipient morbidity. METHODS: Heterotopic small bowel transplantation (SBTx) was performed with Lewis rats as recipients and DA rats as donors, which were immunossupressed with a short course of tacrolimus (FK 506 ) at 1mg/Kg/day for 5 days and distributed in 4 groups: group 1 (n= 4) without both irradiation and DSBMI; Groups 2 (n= 6), 3 (n= 9) and 4 (n= 6) received 100 x 10(6) DSBM cells at the time of the transplant. Groups 3 and 4 were irradiated with 250 and 400 rd respectively. Animals were examined daily for clinical signs of rejection or GVHD. Blood samples were taken weekly for chimeric studies by FC and intestinal biopsies were performed every 2 weeks. RESULTS: Animals in G1 and G2 had minimal rejection at day 15 after SBTx while GVHD was clinically and histologically characterized in G 3 and G 4. Total chimerism and T-cell chimerism was higher in irradiated groups when compared to non-irradiated groups. With exception of G1 and 2 where rejection was the cause of death, all animals in G3 and 4 died of GVHD. CONCLUSION:We concluded that low cytoreductive of irradiation can successfully decrease the graft rejection but not prevent the occurrence of GVHD.

Em estudo recente demonstramos que a infusão de células da medula óssea do doador após o transplante intestinal não aumentou a sobrevida do enxerto quando se utilizou series curtas de drogas imunossupressoras. OBJETIVO: Neste estudo avaliamos se a utilização de diferentes regimes de irradiação em associação com a infusão de medula óssea altera a sobrevida do enxerto e a morbidade sobre receptor. MÉTODOS: Realizou-se o transplante heterotópico de intestino delgado, utilizando-se ratos Lewis como receptores e DA como doadores, imunossuprimidos com FK 506 na dose de 1mg/kg/dia por 5 dias e distribuídos em 4 grupos: G1 (n= 4), não irradiado e sem infusão de medula óssea; G2 (n= 6), G3 (n= 9) e G4 (n= 6) foram infundidos com 100 x 10(6) células de medula após o transplante. Grupos 3 e 4 foram irradiados com 250 e 400 rd respectivamente. Os animais foram examinados diariamente para a detecção de rejeição e reação do enxerto versus hospedeiro, tendo sido colhidas amostras semanais de sangue para estudos de quimerismose biopsias quinzenais da estomia. RESULTADOS: Animais nos G1 e G2 apresentaram rejeição mínima no 15º pós-operatório, enquanto a reação do enxerto versus hospedeiro foi caracterizada nos G3 e G4. Os níveis de quimerismo total e de células T foram maiores nos grupos irradiados em comparação aos não irradiados. A causa mortis nos G1 e G2 foi a rejeição enquanto que nos G3 e G4 foi a reação do enxerto versus hospedeiro. CONCLUSÃO: Concluímos que a utilização de baixas doses de irradiações retardam o aparecimento da rejeição, mas não previne a ocorrência da reação do enxerto versus hospedeiro.