Abstract We present the results of a computational study aimed at capturing the behavior over tim... more Abstract We present the results of a computational study aimed at capturing the behavior over time of Dacron fabric used for surgical correction of aortic aneurysms. The study concerns the problem of compliance mismatch between the graft and the native aorta and is very important to clinicians. The aorta is represented by a sophisticated anisotropic hyperelastic model (GOH), which takes into account the orientation of the collagen fibers. The corrugations present on the Dacron fabric are modeled geometrically using experimental data retrieved from the literature. The viscoelastic behavior of the Dacron graft reported by clinicians is also taken into account. Mechanical quantities experienced by the graft sewn to an aortic segment are obtained using fluid–structure interaction (FSI) simulations assuming realistic blood flow conditions. Both ascending and descending aorta with two curvatures are considered. Results of this study indicate that (i) the strains on the Dacron-aorta structure increase with increasing curvature and over time (ii) the simulations are capable of capturing stress concentrations at the junction of the graft and the aorta and (iii) the wall shear stresses (WSS) are substantially higher on the aortic segment than on the Dacron graft.
Intestinal transplantation includes an heterogeneous group of procedures in which different compo... more Intestinal transplantation includes an heterogeneous group of procedures in which different compositions of organs are transplanted. The current classification includes four groups according to the inclusion of the liver and/or the stomach in the graft: isolated intestinal transplantation, liver-intestinal transplantation, multivisceral transplantation, and modified multivisceral transplantation. Variants exist, the technical evolution having been slow, yet constant over years. The most relevant early technical improvements were aimed at achieving better feasibility and safety of the most difficult aspects of the different procedures, such as removal of the recipient's diseased organs, performing of vascular reconstructions and prevention of complications as with retention of the donor's duodenum and pancreas in liver-intestine transplantation. More recently, apart from a clear definition of the classification of the procedures, progress has been more directed in a conservative direction such as the preservation of the native spleen with and without the pancreas in multivisceral transplants. After achieving consistent satisfactory short-term results, the technical interest in intestinal transplantation is now moved to solutions that, in spite of a possible increased difficulty, may offer better opportunities of mid-term and long-term successes, both in terms of survival and quality of life.
The American Journal of Gastroenterology, Sep 1, 2003
Purpose: Ideally, organ grafting is usually carried out between recipient and donor of identical ... more Purpose: Ideally, organ grafting is usually carried out between recipient and donor of identical blood group to minimize the influence of blood group specific antigens on graft and patients survival. The shortage of suitable donor organs and the clinical urgency can lead in to ...
Incidence of esophagitis among cirrhotics is similar to the general population; post-OLT course o... more Incidence of esophagitis among cirrhotics is similar to the general population; post-OLT course of this entity is not well known. The aim of this study was to assess the incidence of non-infectious esophagitis among OLT recipients. Patients with chronic liver disease who have been considered for transplantation have undergone esophagogastroduodenoscopy (EGD) for examination of the upper gastrointestinal tract. Following transplantation, some of these patients have required EGD for various reasons. EGD findings following transplantation were compared to that individual's pre-transplant findings. There were 173 patients and the median age was 49. The incidence of pre-transplant esophagitis was 7.5%, which increased to 22% after OLT (p > 0.0001). None had specific etiology. Etiology of this increase needs to be further investigated and the effects of immunosuppressive drugs on lower esophageal sprinter and gastric motility should be clarified. Use of acid suppressing drugs during the early post-transplant period should be considered.
As a potent immunosuppressive agent, Tacrolimus is widely used in organ transplantation. Although... more As a potent immunosuppressive agent, Tacrolimus is widely used in organ transplantation. Although complications due to chronic Tacrolimus use are rather well recognized, little is known about acute overdose and its treatment. Phenytoin, an anti-convulsant agent, can induce the Cytochrome P450 enzyme in the liver, which metabolizes Tacrolimus. Therefore, it can be considered as a potential treatment option for acute Tacrolimus toxicity. We hereby report two cases of acute Tacrolimus overdose after Orthotopic Liver Transplantation and the treatment with Phenytoin. Probable mechanisms of metabolism and interactions of these two drugs are discussed and the literature is reviewed.
Since the advent of the potent immunosuppressive agent FK 506, intestinal transplantation has bec... more Since the advent of the potent immunosuppressive agent FK 506, intestinal transplantation has become a feasible therapeutic option for patients with irreversible intestinal failure. In this chapter, we present our clinical experience with intestinal transplantation, focusing on the technical aspects of both the donor and recipient operations. The logistics of the operative procedure have been described previously.
The American Journal of Gastroenterology, Sep 1, 2003
Purpose: Ideally, organ grafting is usually carried out between recipient and donor of identical ... more Purpose: Ideally, organ grafting is usually carried out between recipient and donor of identical blood group to minimize the influence of blood group specific antigens on graft and patients survival. The shortage of suitable donor organs and the clinical urgency can lead in to ...
Abstract We present the results of a computational study aimed at capturing the behavior over tim... more Abstract We present the results of a computational study aimed at capturing the behavior over time of Dacron fabric used for surgical correction of aortic aneurysms. The study concerns the problem of compliance mismatch between the graft and the native aorta and is very important to clinicians. The aorta is represented by a sophisticated anisotropic hyperelastic model (GOH), which takes into account the orientation of the collagen fibers. The corrugations present on the Dacron fabric are modeled geometrically using experimental data retrieved from the literature. The viscoelastic behavior of the Dacron graft reported by clinicians is also taken into account. Mechanical quantities experienced by the graft sewn to an aortic segment are obtained using fluid–structure interaction (FSI) simulations assuming realistic blood flow conditions. Both ascending and descending aorta with two curvatures are considered. Results of this study indicate that (i) the strains on the Dacron-aorta structure increase with increasing curvature and over time (ii) the simulations are capable of capturing stress concentrations at the junction of the graft and the aorta and (iii) the wall shear stresses (WSS) are substantially higher on the aortic segment than on the Dacron graft.
Intestinal transplantation includes an heterogeneous group of procedures in which different compo... more Intestinal transplantation includes an heterogeneous group of procedures in which different compositions of organs are transplanted. The current classification includes four groups according to the inclusion of the liver and/or the stomach in the graft: isolated intestinal transplantation, liver-intestinal transplantation, multivisceral transplantation, and modified multivisceral transplantation. Variants exist, the technical evolution having been slow, yet constant over years. The most relevant early technical improvements were aimed at achieving better feasibility and safety of the most difficult aspects of the different procedures, such as removal of the recipient's diseased organs, performing of vascular reconstructions and prevention of complications as with retention of the donor's duodenum and pancreas in liver-intestine transplantation. More recently, apart from a clear definition of the classification of the procedures, progress has been more directed in a conservative direction such as the preservation of the native spleen with and without the pancreas in multivisceral transplants. After achieving consistent satisfactory short-term results, the technical interest in intestinal transplantation is now moved to solutions that, in spite of a possible increased difficulty, may offer better opportunities of mid-term and long-term successes, both in terms of survival and quality of life.
The American Journal of Gastroenterology, Sep 1, 2003
Purpose: Ideally, organ grafting is usually carried out between recipient and donor of identical ... more Purpose: Ideally, organ grafting is usually carried out between recipient and donor of identical blood group to minimize the influence of blood group specific antigens on graft and patients survival. The shortage of suitable donor organs and the clinical urgency can lead in to ...
Incidence of esophagitis among cirrhotics is similar to the general population; post-OLT course o... more Incidence of esophagitis among cirrhotics is similar to the general population; post-OLT course of this entity is not well known. The aim of this study was to assess the incidence of non-infectious esophagitis among OLT recipients. Patients with chronic liver disease who have been considered for transplantation have undergone esophagogastroduodenoscopy (EGD) for examination of the upper gastrointestinal tract. Following transplantation, some of these patients have required EGD for various reasons. EGD findings following transplantation were compared to that individual's pre-transplant findings. There were 173 patients and the median age was 49. The incidence of pre-transplant esophagitis was 7.5%, which increased to 22% after OLT (p > 0.0001). None had specific etiology. Etiology of this increase needs to be further investigated and the effects of immunosuppressive drugs on lower esophageal sprinter and gastric motility should be clarified. Use of acid suppressing drugs during the early post-transplant period should be considered.
As a potent immunosuppressive agent, Tacrolimus is widely used in organ transplantation. Although... more As a potent immunosuppressive agent, Tacrolimus is widely used in organ transplantation. Although complications due to chronic Tacrolimus use are rather well recognized, little is known about acute overdose and its treatment. Phenytoin, an anti-convulsant agent, can induce the Cytochrome P450 enzyme in the liver, which metabolizes Tacrolimus. Therefore, it can be considered as a potential treatment option for acute Tacrolimus toxicity. We hereby report two cases of acute Tacrolimus overdose after Orthotopic Liver Transplantation and the treatment with Phenytoin. Probable mechanisms of metabolism and interactions of these two drugs are discussed and the literature is reviewed.
Since the advent of the potent immunosuppressive agent FK 506, intestinal transplantation has bec... more Since the advent of the potent immunosuppressive agent FK 506, intestinal transplantation has become a feasible therapeutic option for patients with irreversible intestinal failure. In this chapter, we present our clinical experience with intestinal transplantation, focusing on the technical aspects of both the donor and recipient operations. The logistics of the operative procedure have been described previously.
The American Journal of Gastroenterology, Sep 1, 2003
Purpose: Ideally, organ grafting is usually carried out between recipient and donor of identical ... more Purpose: Ideally, organ grafting is usually carried out between recipient and donor of identical blood group to minimize the influence of blood group specific antigens on graft and patients survival. The shortage of suitable donor organs and the clinical urgency can lead in to ...
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