In this animal model, changes of intracardiac impedance revealed hemodynamic deterioration as reflected by EDV and EDP pressure. Thus, intracardiac impedance is a promising new application to monitor heart failure status within implantable devices.
Background: Anhepatic animal models are suitable for simulating acute liver failure. Hepatectomy in pigs includes en bloc resection of the vena cava, and therefore, a temporary extracorporeal bypass and total clamping of the inferior vena cava are needed. These steps cause severe depression of circulation with impaired survival. Methods: Previous to en bloc hepatectomy including retrohepatic vena cava in 20 female pigs, a Y-shaped bypass was implanted starting with end-to-side anastomosis between the vena cava and the portal vein, followed by anastomosis to the intrathoracic vena cava. Results: Blood flow was constant during and after hepatectomy because vessels were only partially clamped. No venous stasis of intestinal organs was observed. Hemodynamic parameters like heart rate, mean arterial pressure, central venous pressure, pulse oximetry and intracranial pressure remained extremely stabile during and after hepatectomy. Postoperative survival time was 100% after 12 h. Maximum survival time was 84.9 h and mean survival time 51.2 ± 18.7 h. All animals died from multiple organ failure. Intracranial pressure remained stable during the surgical procedure and rose continuously until death. The autopsy showed massive brain edema. Conclusions: This new surgical technique is safe and easy to perform and permits total hepatectomy with minimal blood loss under stable circulation without requiring an extracorporeal bypass.
The strong correlation with SV allows the application of intracardiac impedance measurements for an implant-based continuous monitoring of cardiac function. Impedance may also be used for hemodynamic optimization of cardiac resynchronization therapy.
Because of the ongoing organ shortage, kidneys with atypical anatomy like horseshoe kidneys must be considered for transplantation [1,2].A 44-year-old male (blood group B) with no history of kidney or urinary tract disorders (creatinine 0.5 mg/dl) was diagnosed as being brain dead after spontaneous subarachnoidal bleeding.A horseshoe-shaped kidney was diagnosed intraoperatively, and after harvesting the liver and the pancreas nephrectomy of both kidneys together with the aorta and vena cava was performed by an external transplant team following a standard technique.Before the organs were offered to our centre, they had not been accepted for transplantation by two major transplant centres because of suspected complex anatomy, large mass (estimated to be twice as large per side when compared with a normal adult kidney) and an enlarged isthmus.After a long allocation process and time-consuming external cross match, inspection revealed a normal pancreas and the left kidney to have normal vascular anatomy, whereas the right kidney had one main with two accessory arteries and two separate veins. The isthmus contained normal kidney parenchyma. Injection of contrast medium into both ureters showed that each kidney had separate urinary-collecting systems.The kidney was divided sharply followed by suture ligation of all vascular and tubular structures. The cut surfaces were then oversewn using interrupted sutures.The left side of the kidney together with the pancreasduodenal graft [cold ischemia time (CIT) 19 h] from the same donor was transplanted after 21 h CIT using a transperitoneal standard technique, namely to a 54-yearold woman with type I diabetes and renal failure requiring hemodialysis.Initial function of both organs was normal with good diuresis and normal blood glucose levels. After one shot of antithymocyte globulin (7 mg/kg), immunosuppression was based on tacrolimus, mycophenolat mofetil and steroids.Unfortunately, the completely normal functioning pancreas graft was lost in the third week after transplantation because of duodenal perforation. Kidney function is normal to date (creatinine 0.5 mg/dl).The right side of the kidney was successfully transplanted after 25 h CIT to a 44-year-old male on hemodialysis because of focal sclerosing glomerulonephritis. In a technically demanding and time-consuming back table procedure, the three arteries and the two veins were reconstructed -forming one common patch each. Reperfusion was excellent with immediate organ function. Immunosuppression consisted of tacrolimus, mycophenolate mofetil and steroids. Repeat postoperative sonography revealed no retroperitoneal collection [3]. The patient was discharged 2 weeks after operation with normal kidney function.Horseshoe kidneys have an estimated incidence of 1:800 population and are frequently accompanied by vascular and urinary tract abnormalities [4][5][6].Several cases of transplantation have been described, some transplanted split and some en bloc [1,7]. Even successful living donor transplantation of a horseshoe kidne...
The shortage of organ donors has impeded the development of human hepatocyte transplantation. Immortalized hepatocytes could provide an unlimited supply of transplantable cells. To determine whether immortalized hepatocytes could provide global metabolic support in end-stage liver disease, 42 immortalized rat hepatocytes clones were developed by transduction with Artifi cal Human Chromosome (HAC) encoding the Simian virus 40 T antigen (SV40Tag) . The SV40Tag sequence and a suicide gene, herpes simplex virus thymidine kinase (HSV-tk), were fl anked by FRT sequences so that they could be excised by FRT recombination. When transplanted into the spleen of retrosin treated non albumin rats with 2/3 hepatectomy with FK506 (R-NARs), immortalized hepatocyte clones prevented the development of albumin. The protection was reversed by Ganciclovir treatment, which kills HSV-tk expressing cells. Three experimental groups were used for alnumin analysis: (G1) non albumin rats with 2/3 hepatectomy only (R-NARs) (n=4); (G2) R-NARs and intrasplenic transplantation of 3x107 primary hepatocytes (pHTx) (n=4); (G3) R-NARs and intrasplenic transplantation of 3x107 immortalized hepatocytes (iHTx) (n=4) All HTx group(G2-3) were made albumin but immortalized hepatocytes were not signifi cantly elevated albumin level conpared with primary hepatocyte. Immortalized hepatocytes group were not shown up tumor after one month HTx. The metabolic support provided by the immortalized cells not equalled that observed after transplantation of primary rat hepatocytes, but in afuthur can be engineered to contain safeguards that could make them clinically useful.
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