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Featured researches published by Bakr Nour.


The New England Journal of Medicine | 1995

The Association of Epstein–Barr Virus with Smooth-Muscle Tumors Occurring after Organ Transplantation

Elsie S. Lee; Joseph Locker; Michael A. Nalesnik; Jorge Reyes; Ronald Jaffe; Mouied Alashari; Bakr Nour; Andreas G. Tzakis; Paul S. Dickman

BACKGROUND Epstein-Barr virus (EBV) has been associated with nasopharyngeal carcinoma, some lymphomas, and lymphoproliferative disease after organ transplantation. Many lymphoproliferative tumors that occur after transplantation are clonal, a property that classifies them as neoplastic. Clonality can be determined by analysis of the extrachromosomal circular DNA episomes produced by EBV infection. METHODS We describe three young children in whom smooth-muscle tumors developed 18 months to 5 1/2 years after liver transplantation with immunosuppression. We examined the tumors by microscopy and with immunohistochemical studies and molecular genetic analyses of the EBV DNA: RESULTS The tumors were composed of spindle cells with smooth-muscle features and resembled those described in patients with the acquired immunodeficiency syndrome. Immunohistochemical analysis was negative for EBV latent membrane protein and EBV receptor (CD21), but positive for EBV nuclear antigen 2. In situ hybridization revealed nuclear EBV sequences, and molecular genetic analysis showed the EBV genome to be clonal in all three patients. CONCLUSIONS Smooth-muscle tumors that developed after organ transplantation contained clonal EBV, suggesting that the virus has a role in the development of these neoplastic lesions.


Annals of Surgery | 1992

Intestinal transplantation in composite visceral grafts or alone.

Satoru Todo; Andreas G. Tzakis; Kareem Abu-Elmagd; Jorge Reyes; K. Nakamura; Adrian Casavilla; Rick Selby; Bakr Nour; Harlan I. Wright; John J. Fung; Anthony J. Demetris; David H. Van Thiel; Thomas E. Starzl

Under FK 506-based immunosuppression, the entire cadaver small bowel except for a few proximal and distal centimeters was translated to 17 randomly matched patients, of whom two had antigraft cytotoxic antibodies (positive cross-match). Eight patients received the intestine only, eight had intestine in continuity with the liver, and one received a full multivisceral graft that included the liver, stomach, and pancreas. One liver-intestine recipient died after an intestinal anastomotic leak, sepsis, and graft-versus-host disease. The other 16 patients are alive after 1 to 23 months, in one case after chronic rejection, graft removal, and retransplantation. Twelve of the patients have been liberated from total parenteral nutrition, including all whose transplantation was 2 months or longer ago. The grafts have supported good nutrition, and in children, have allowed growth and weight gain. Management of these patients has been difficult and often complicated, but the end result has been satisfactory in most cases, justifying further clinical trials. The convalescence of the eight patients receiving intestine only has been faster and more trouble free than after liver-intestine or multivisceral transplantation, with no greater difficulty in the control of rejection.


Journal of Vascular and Interventional Radiology | 1994

Percutaneous Transluminal Angioplasty of Venous Anastomotic Stenoses Complicating Liver Transplantation: Intermediate-term Results☆

Albert B. Zajko; Rubin Sheng; Klaus M. Bron; Jorge Reyes; Bakr Nour; Andreas G. Tzakis

PURPOSE The authors evaluated the safety and efficacy of percutaneous transluminal angioplasty (PTA) for the treatment of venous stenoses in liver transplant recipients. PATIENTS AND METHODS Over a 5-year period, 15 venous stenoses were treated with PTA in 12 patients with liver transplants (seven children and five adults). PTA was performed for portal vein stenoses in five patients, inferior vena cava (IVC) stenoses (n = 6) in five patients, combined superior mesenteric vein-portal vein graft anastomosis and hepatic vein-IVC anastomosis in one patient, and combined IVC and hepatic vein-IVC anastomosis in one patient. PTA was repeated in three patients (five procedures) for recurrent IVC stenoses. RESULTS Initial technical and clinical success of PTA was achieved in 11 patients (92%); failure occurred in one patient (8%) with a portal vein anastomotic stenosis. No complications occurred in the immediate post-procedure period (up to 7 days). Nine patients (75%) are clinically well, with follow-up ranging from 7 to 33 months (mean, 18 months). Two of them required one or more repeated PTA procedures to maintain vessel patency. One patient required retransplantation for chronic rejection at 3 months, and another died of gastrointestinal tract bleeding from a gastric ulcer at 2 months after initially successful IVC PTA. CONCLUSIONS PTA is a safe procedure for the treatment of venous anastomotic stenoses in liver transplant recipients. PTA of portal vein anastomotic stenosis has favorable intermediate-term results. Repeat PTA may be necessary in some cases of IVC anastomotic stenoses to maintain vessel patency and avoid surgical revision or retransplantation.


Transplantation | 1994

Small intestinal transplantation in humans with or without the colon.

Satoru Todo; Andreas G. Tzakis; Jorge Reyes; Kareem Abu-Elmagd; Hiroyuki Furukawa; Bakr Nour; Adrian Casavilla; K. Nakamura; John J. Fung; A. J. Demetris; Thomas E. Starzl

Under FK506-based immunosuppression, 16 cadaveric small bowel transplantations were performed in 15 recipients with (n=5) or without (n=11) the large bowel. Twelve (80%) patients are alive after 1.5 to 19 months, 11 bearing their grafts, of which 4 include colon. The actuarial one-year patient and graft survivals are 87.5% and 65.9%, respectively. Five grafts were lost to acute (n=4) or chronic (n=l) rejection, and 3 of these patients subsequently died after 376, 440, and 776 days total survival. Six recipients developed severe CMV infection that was strongly associated with seronegative status preoperatively and receipt of grafts from CMV positive donors; 3 died, and the other 3 required prolonged hospitalization. Currently, 9 patients are free from TPN 1–18 months postoperatively, 2 require partial TPN, and one has returned to TPN after graft removal. The results show the feasibility of small bowel transplantation but emphasize the difficulty of managing these recipients not only early but long after their operation.


Annals of Surgery | 1994

Single-center experience with primary orthotopic liver transplantation with FK 506 immunosuppression.

S. Todo; John J. Fung; Thomas E. Starzl; Andreas G. Tzakis; Howard R. Doyle; Kareem Abu-Elmagd; Ashokkumar Jain; R. Selby; Oscar Bronsther; Wallis Marsh; Hector Ramos; Jorge Reyes; Timothy Gayowski; Adrian Casavilla; Forrest Dodson; H Furukawa; Ignazio R. Marino; Antonio Pinna; Bakr Nour; Nicolas Jabbour; George V. Mazariegos; John McMichael; Shimon Kusne; Raman Venkataramanan; Vijay Warty; Noriko Murase; Anthony J. Demetris; Shunzaburo Iwatsuki

OBJECTIVE The efficacy for primary orthotopic liver transplantation of a new immunosuppressive agent, FK 506 (tacrolimus, Prograf, Fujisawa USA, Deerfield, IL), was determined. SUMMARY BACKGROUND DATA After 3 years of preclinical research, a clinical trial of FK 506 for orthotopic liver transplantation was begun in February 1989, first as a rescue therapy for patients with intractable rejection with conventional immunosuppression, then as a primary drug. METHODS Between August 1989 and December 1993, 1391 recipients (1188 adult and 203 pediatric) of primary liver allografts were treated with FK 506 from the outset. Results from these patients were analyzed and compared with those of 1212 historical control patients (971 adult and 241 pediatric) given cyclosporine-based immunosuppression. RESULTS Actuarial survival at 4 years was 86.2% with FK 506 versus 65.5% with cyclosporine in the pediatric patients (p < 0.0000) and 71.4% versus 65.5% in the adults (p < 0.0005). The need for retransplantation was reduced significantly for FK 506 patients. Four-year graft survival was 77.0% with FK 506 versus 48.4% with cyclosporine in the pediatric patients (p < 0.0000), and 61.9% with FK 506 versus 51.4% with cyclosporine in the adult recipients (p < 0.0000). Regression analysis revealed that reduction in mortality or graft loss from uncontrollable rejection, sepsis, technical failure, and recurrent original liver disease were responsible for the improved results with FK 506 therapy. CONCLUSIONS FK 506 is a potent and superior immunosuppressive agent for orthotopic liver transplantation.


Transplantation | 1995

Abdominal multivisceral transplantation

Satoru Todo; Andreas G. Tzakis; Kareem Abu-Elmagd; Jorge Reyes; H Furukawa; Bakr Nour; John J. Fung; A. J. Demetris; Thomas E. Starzl

Under FK506-based immunosuppression, 13 abdominal multivisceral transplantations were performed in 6 children and 7 adults. Of the 13 recipients, 7 (53.8%) are alive and well with functioning grafts after 9 to 31 months. Six recipients died: three from PTLD, one from rejection, one from sepsis, and one from respiratory failure. In addition to rejection, postoperative complications occurring in more than isolated cases included PTLD (n = 6), abdominal abscess formation (n = 5), pancreatitis (n = 3), and ampullary dysfunction (n = 2). In addition, infection by enteric microorganisms was common during the early postoperative period. Currently, all 7 survivors are on an oral diet and have normal liver function. Two recipients (one insulin-dependent) require antidiabetes treatment, in one case following distal pancreatectomy and in the other after two episodes of pancreatic rejection. Thus, abdominal multivisceral transplantation is a difficult but feasible operation that demands complex and prolonged posttransplantation management. It is not yet ready for application and awaits a better strategy of immune modulation.


Transplantation | 1993

Parvovirus B19 infection in pediatric transplant patients.

Bakr Nour; Michael Green; Marian G. Michaels; Jorge Reyes; Andreas G. Tzakis; Gartner Jc; McLoughlin L; Thomas E. Starzl

Evidence of recent parvovirus virus infection (as determined by the presence of a positive IgM antibody titer) without other identified causes of anemia was found in 5 of 26 pediatrie solid-organ transplant recipients evaluated for moderate-to-severe anemia between June 1990 and July 1991. Anemia tended to be chronic (median duration of anemia at the time of diagnosis was 12 weeks) and was associated with normal red blood cell indices in the absence of reticulocytes. The median age of the children at the time of presentation with anemia due to parvovirus was 1.8 years at a median time of 8 months after transplantation. Four of the 5 children were treated with i.v. immunoglobulin because of persistance of anemia requiring blood transfusions. A response characterized by an increase in reticulocyte count and normalization of hemoglobin was seen in each of these patients 2–4 weeks after treatment. The remaining patient experienced a spontaneous recovery from her anemia. Parvovirus infection should be included in the differential diagnosis of solid-organ transplant recipients presenting with severe anemia associated with low or absent reticulocytes.


Journal of Pediatric Surgery | 1995

Orthotopic liver transplantation for ornithine transcarbamylase deficiency with hyperammonemic encephalopathy.

Toshimichi Hasegawa; Andreas G. Tzakis; Satoru Todo; Jorge Reyes; Bakr Nour; David N. Finegold; Thomas E. Starzl

Ornithine transcarbamylase (OTC) deficiency is an X chromosome-linked disorder causing hyperammonemic encephalopathy with a very poor prognosis. We describe here two patients with OTC deficiency, one a late on-set female patient (case 1) and the other a neonatal-onset male patient (case 2), who were successfully treated with orthotopic liver transplantation (OLTx). The OTC activity in the excised liver was 10% and 0% of control, respectively. Hyperammonemic encephalopathy was controlled with medical therapy in case 1 until the of 5 years, but the complicated course in case 2 in which hyperammonemia required peritoneal dialysis and hemodialysis in the neonatal period necessitated OLTx with a reduced-size liver at the age of 80 days. Both patients had restoration of serum ammonia level to normal in 2 and 3 days after liver replacement, and both patients have normal neurological and developmental status after 2 and 0.5 years of postoperative follow-up. These cases illustrate not only the metabolic cure of this disorder, but also the need to preserve neurological integrity by aggressive medical management of the hyperammonemia preoperatively and early surgical intervention when indicated, even if this is required very early in life.


Digestive Diseases and Sciences | 1995

Arterioportal fistula following liver biopsy. Three cases occurring in liver transplant recipients.

Nicolas Jabbour; Jorge Reyes; Albert B. Zajko; Bakr Nour; Andreas G. Tzakis; Thomas E. Starzl; David H. Van Thiel

SummaryAlthough liver biopsy is a very useful procedure used frequently in the diagnosis and management of liver dysfunction occurring after orthotopic liver transplantation, complications can occur with its use. An unusual complication of arterioportal fistula is reported here.Based upon this small series of an unusual event and the knowledge that the posttransplant liver may be more hypervascular than prior to OLTx and that it is uniquely susceptible to hepatic infarction and abscess formation, any attempt at fistula closure should be considered carefully prior to initiating the therapy (15). Unless a serious complication occurs [such as a transient biliary obstruction due to hemobilia as occurred in case 2, portal hypertension as also occurred in case 2, or systemic sepsis or other symptoms develop related directly to the fistula], simple observation may be the best choice of action. Should therapy be required, hepatic arterial embolization should be reserved for adults with intrahepatic fistulas. Primary surgical closure of intrahepatic fistula should be reserved for cases of extrahepatic fistula.


Journal of Pediatric Surgery | 1994

Early tolerance in pediatric liver allograft recipients.

Andreas G. Tzakis; Jorge Reyes; Adrianna Zeevi; Hector Ramos; Bakr Nour; Nancy L. Reinsmoen; Satoru Todo; Thomas E. Starzl

The authors report on six pediatric liver transplant recipients for whom allograft tolerance occurred shortly after transplantation (ie, less than 1.5 years). All the patients had associated life-threatening viral complications. They are currently immunocompetent. The tolerant state may be related to the development of a TH2 cytokine pattern.

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Jorge Reyes

University of Washington

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S. Todo

University of Pittsburgh

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John J. Fung

St Lukes Episcopal Hospital

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Ahmet Gurakar

University of Oklahoma Health Sciences Center

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A. Tzakis

University of Pittsburgh

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Anthony Sebastian

University of Oklahoma Health Sciences Center

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