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S Todo

Publications and source records attributed to S Todo.

At least 217 records · Page 12Linked to original sources
PubMed1995

Intestinal and multivisceral transplantation.

Intestinal transplantation for treatment of irreversible intestinal failure is the newest of the transplantation operations to be developed for clinical use. Because the bowel is more vulnerable to rejection than heart, lung, kidney, liver, or pancreas, practical clinical intestinal transplantation has been relatively slow to develop and is still in its infancy. Imaging studies play an important role in the initial evaluation of the residual native gastrointestinal tract for patients who are potential candidates for enteric implant. After transplantation, gastrointestinal contrast studies help monitor the recovery of gastrointestinal function and permit early detection of postoperative technical complications. CT, ultrasound, and angiography are useful for diagnosis and in some cases treatment of a variety of posttransplantation complications.

Humans↗
PubMed1995

Assessment of five-year experience with abdominal organ cluster transplantation.

BACKGROUND: Upper abdominal exenteration (resection of the liver, stomach, spleen, pancreaticoduodenal complex, and part of the colon) for the treatment of otherwise unresectable tumors is one of the more radical operations in oncology. This study was done to analyze retrospectively a five-year experience with exenteration in 57 patients treated with variations of resectional and transplant reconstructive techniques. STUDY DESIGN: Sixty-one transplantations were performed upon 57 patients. Three different organ replacement techniques were used: liver-pancreas-duodenum en bloc (original procedure), liver only (modified procedure), and liver plus pancreatic islets. The diagnoses were cholangiocarcinoma (20 patients), hepatocellular carcinoma (12 patients), endocrine neoplasms (14 patients), sarcoma (six patients), and adenocarcinoma of the pancreas (two patients), colon (two patients), or gallbladder (one patient). Analyses of survival and tumor recurrence were stratified by procedure variations, type and extent of tumor, and immunosuppressive regimen. RESULTS: The three month and one, two, three, and five year actuarial patient survival rates were 82, 56, 38, 33, and 30 percent, respectively. Eighteen (31.5 percent) of the 57 patients are alive after 425 15 (standard deviation) months (range of 17 to 61 months) and 12 patients are tumor free. The actuarial survival rates stratified by transplantation procedure, immunosuppression, and tumor diagnosis and extent showed no statistically significant differences beyond the three different transplantation groups. Endocrine tumors had a better three-year survival rate (64 percent) than sarcoma (44 percent), hepatocellular carcinoma (25 percent), cholangiocarcinoma (20 percent), and the other adenocarcinomas (20 percent). Twenty-three patients (40 percent) died as a result of tumor recurrence. Patients with combined factors of no lymph node involvement, absence of vascular invasion, and metastases to the liver only (11 patients) had the lowest incidence of recurrence (27 compared to 73.5 percent, p = 0.006). CONCLUSIONS: Patients with unresectable endocrine neoplasms, fibrolamellar hepatocellular carcinoma, and selected cholangiocarcinoma confined to the liver can benefit from this radical operative approach. Patients with sarcoma can achieve long survival periods but have a high recurrence rate.

Abdominal Neoplasms↗
PubMed1995

Successful allogeneic bone marrow transplantation in a case with myelodysplastic syndrome which developed following Fanconi anemia.

We report the case of a 14-year-old boy with myelodysplastic syndrome (MDS/RAEB) which developed following Fanconi anemia. The patient received BMT from an HLA-identical sister. Based on the in vitro CY-sensitivity test, 100 mg/kg of CY was administered for conditioning combined with 6 Gy TBI. Mucosal symptoms such as stomatitis, diarrhea and hematuria were severe, but manageable, and engraftment was successful. The patient has maintained normal trilineage hematopoiesis with > 90% Karnofsky score for 30 months with disappearance of a clonal chromosomal abnormality (47,XY, +i(lq)) which was detected before BMT.

Adolescent↗
PubMed1995

The current status of hepatic transplantation at the University of Pittsburgh.

Tacrolimus is a more potent and satisfactory immunosuppressant than CyA for combination therapy with prednisone. In randomized trials comparing the 2 drugs, the ability of tacrolimus to rescue intractably rejecting grafts on the competing CyA arm allowed equalization of patient and graft survival on both arms when the intent-to-treat analytic methodology was applied. The ability of tacrolimus to systematically rescue the treatment failures of CyA suggested, as a matter of common sense, that it is the preferred baseline drug for hepatic transplantation. This conclusion was supported by analysis of secondary end points, including the ability to prevent rejection. Hepatic-intestinal, multivisceral and isolated intestinal transplantation became feasible on a practical basis only after the advent of tacrolimus. Nevertheless, better management strategies must be devised before intestinal transplantation, alone or with other abdominal viscera, will meet its potential. One such strategy is based on the discovery of the presence of previously unsuspected, low-level donor leukocyte chimerism in long-surviving allograft recipients. We believe that this chimerism is the essential explanation for the feasibility of organ transplantation and a link to the acquired neonatal tolerance demonstrated by Billingham, Brent and Medawar (32). The hematolymphopoietic chimerism in organ recipients explains why weaning to a drug-free state in selected long-term survivors is frequently feasible and particularly if the allograft is a liver. Weaning should never be attempted without a stepwise protocol and careful monitoring of graft function. Recognition of the natural chimerism that develops after whole organ transplantation has led to efforts to augment it with perioperative donor BM infusion. This procedure has been shown to be free of significant complications (including GVHD) in all kinds of whole organ recipients, including those given intestine. The prospects of clinical xenotransplantation must be evaluated in the same context of chimerism as that delineated for allotransplantation with the discovery of spontaneous chimerism. Before addressing chimerism-related questions in xenotransplantation, the additional barrier of the complement activation syndromes that cause hyperacute rejection will have to be surmounted. Although measures to effectively transplant xenografts have so far eluded us, the availability of the more potent drug, tacrolimus, and recognition of the seminal basis of allograft (or xenograft) acceptance via chimerism has inserted an element of reality into the largely wishful thinking that has been evident in discussions about the future of xenotransplantation.

Adolescent↗
PubMed1994

Modified simple cold storage of rat livers with UW solution.

Rat livers were preserved with the conventional use of UW solution for 30, 42, and 48 hr and compared with livers in which the vascular bed was expanded with an additional 10 to 60 ml UW/100 g liver. The extra UW, expressed as % liver weight, was entrapped during final portal infusion by typing off the supra- and infrahepatic inferior vena cava. A beneficial influence of the vascular expansion was most pronounced in the 40% group, with 10/10, 5/10, and 3/10 long-term survivors following transplantation after 30, 42, and 48 hr preservation versus 3/10 and 0/10 after 30 and 42 hr in the 0% controls. In separate experiments, surrogate indices of preservation quality following reperfusion explained this effect. The 40%--and, to a lesser extent, 20%--livers had higher and more uniformly distributed portal blood flow, better tissue oxygenation, smaller increases in postperfusion liver enzymes, higher adenine nucleotides and energy charge, and less histopathologic evidence of hemorrhage and congestion. Pressure changes in the vena cava fluid sump in additional experiments indicated that retrograde infusion of the trapped UW solution occurred in all of the 10-60% groups during the first 6 hr with stable pressures of 1.5 to 3 cm H2O thereafter. Collectively, these data suggest that the much discussed selective vulnerability of the microvasculature of stored allografts is due in part (or principally) to its selective lack of long-term exposure to the UW solution, which drains out of the open vessels but not from the parenchyma. The potential clinical exploitation of this concept is discussed.

Adenosine↗
PubMed1994

Combined immunosuppressive therapy with low dose FK506 and antimetabolites in rat allogeneic heart transplantation.

Following rat heterotopic heart allotransplantation, low to lethal doses of the antimetabolites mizoribine (MIZ), RS-61443 (RS), and AZA were given alone or in combination with subtherapeutic doses of FK506 (0.04 mg/kg/day) for 14 days after transplantation. With the median effect analysis of Chou and Kahan for quantitative drug interactions, substantial therapeutic synergism was demonstrated between FK506 and non-toxic doses of MIZ (2.5, 5, and 10 mg/kg/day) or AZA (5, 30, and 45 mg/kg/day), which was particularly evident with the lowest dose MIZ (2.5 mg/kg/day). When FK506 was used in combination with MIZ or AZA but not with RS, the maximum effect (peak median graft survival) was enhanced significantly from 15 days (MIZ alone) to 26 days (P < 0.05), and from 19 days (AZA alone) to 32 days (P < 0.01). In contrast, RS interacted with FK506 no more than additively. Although RS was the most powerful single antimetabolite, the best overall survival was obtained by combining AZA and FK506. The addition of FK506 did not significantly increase the percent mortality and LD50 of the antimetabolites.

Animals↗
PubMed1994

Small intestinal transplantation in humans with or without the colon.

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 = 1) 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.

Adult↗
PubMed1994

Liver transplantation without the use of blood products.

OBJECTIVES: To examine the techniques and the outcome of liver transplantation with maximal conservation of blood products and to analyze the potential benefits or drawbacks of blood conservation and salvage techniques. DESIGN: Case series survey. SETTING: Tertiary care, major university teaching hospital. PATIENTS AND METHODS: Four patients with religious objections to blood transfusions who were selected on the basis of restrictive criteria that would lower their risk for fatal hemorrhage, including coagulopathy, a thrombosed splanchnic venous system requiring extensive reconstruction, active bleeding and associated medical complications. All patients were pretreated with erythropoietin to increase production of red blood cells. All operations were performed at the same institution, with a 36-month follow-up. INTERVENTIONS: Orthotopic liver transplantation that used blood salvage, plateletpheresis, and autotransfusion and the withholding of the use of human blood products with the exception of albumin. MAIN OUTCOME MEASURES: Survival and postoperative complications, with the effectiveness of erythropoietin and plateletpheresis as secondary measures. RESULTS: All patients are alive at 36 months after orthotopic liver transplantation. One patient, a minor (13 years of age), was transfused per a state court ruling. Erythropoietin increased the production of red blood cells as shown by a mean increase in hematocrit levels of 0.08. Platelet-pheresis allowed autologous, platelet-rich plasma to be available for use after allograft reperfusion. Three major complications were resolved or corrected without sequelae. Only one patient developed postoperative hemorrhage, which was corrected surgically. The mean charge for bloodless surgery was $174,000 for the three patients with United Network for Organ Sharing (UNOS) status 3 priority for transplantation. This result was statistically significant when these patients were compared with all the patients with UNOS status 3 priority during the same period who met the same restrictive guidelines (P < .05). Only 19 of 1009 orthotopic liver transplantations performed at our institution were similar according to the UNOS status and the fulfillment of the guidelines. The mean charge for these comparison patients was $327,000, 3.8% of which was related to transfusions. CONCLUSIONS: Orthotopic liver transplantation without the use of blood products is possible. Blood conservation techniques do not increase morbidity or mortality and can result in fewer transfusion-related, in-hospital charges.

Adolescent↗
PubMed1994

Can adenine nucleotides predict primary nonfunction of the human liver homograft?

Sixty-eight primary liver grafts were analyzed to see whether adenine nucleotides (AN: ATP, ADP, and AMP) or purine catabolites (PC: adenosine, inosine, hypoxanthine, and xanthine) of tissue or effluent can predict primary graft nonfunction. AN, PC, and nicotinamide adenine dinucleotide, oxidized form (NAD+) of the tissue before (pretransplant) and after graft reperfusion (post-transplant) and of the effluent were analyzed. The graft outcome was classified into two groups (group A: successful, n = 64; group B: primary nonfunctioning, n = 4). No significant differences were observed in pretransplant measurements between groups A and B, whereas ATP, ADP, total AN, total AN + total PC (T) and NAD+, in post-transplant tissues, were significantly higher in group A. Xanthine in the effluent was significantly higher in group B than in group A. ATP, ADP, total AN, T, and NAD+ in post-transplant tissue were significantly associated with primary graft nonfunction by logistic regression analysis.

Adenine Nucleotides↗
PubMed1994

Is rejection a diffuse or localized process in small-bowel transplantation?

Utilization of endoscopy to both visualize and selectively biopsy an intestinal allograft has become the standard for early recognition and treatment of intestinal allograft rejection. Despite the widespread acceptance of the need for selective mucosal biopsies, it has not been shown that the histological features of intestinal allograft rejection are either localized or occur as part of a more diffuse phenomenon within a tubular allograft. To resolve these issues, 88 ileoscopies were performed in 12 small-bowel allograft recipients and mucosal biopsy samples were obtained at 5, 10, and 15 cm, respectively, from the ileal stoma. Each mucosal biopsy was labeled, processed, and evaluated individually for the presence and severity of any evidence for allograft rejection. The data obtained suggest that intestinal allograft rejection is a diffuse process, and biopsies obtained randomly from an ileal graft are likely to demonstrate evidence of allograft rejection when such is present.

Adult↗
PubMed1994

Immunohistochemical study of enteric nervous system after small bowel transplantation in humans.

The neurohormonal structures of two human intestines removed due to rejection 22 months and eight months after intestinal transplantation were studied by an indirect immunohistochemical method and compared with normal ileum. The distribution and density of neurons immunoreactive for tyrosine hydroxylase, substance P, calcitonin gene-related peptide, neuropeptide Y, vasoactive intestinal peptide, galanin, gastrin-releasing peptide, L-enkephalin, and somatostatin were examined. Mucosal endocrine cells immunoreactive for somatostatin, peptide YY, and glucagon were also examined. Extrinsic adrenergic fibers and perivascular fibers were absent in all intestinal layers of the failed grafts. The distribution of intrinsic neurons was unchanged; however, the density was decreased by one rank. Distribution of endocrine cells of the first graft was similar to the normal. Extrinsic fibers were not detected by immunohistochemistry in human small intestinal grafts following long-term survival and eventual rejection, while the immunohistochemical expression of intrinsic neural and endocrine transmitters were well preserved.

Adult↗
PubMed1994

Early tolerance in pediatric liver allograft recipients.

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.

Female↗