PubMed Health⌕ Search

Biomedical subjects

I J Fox

Publications and source records attributed to I J Fox.

At least 37 records · Page 2Linked to original sources
PubMed1998

Correlation of mucosal disaccharidase activities with histology in evaluation of rejection following intestinal transplantation.

Following intestinal transplantation, we have found that recovery from severe rejection may be difficult to identify. In this study we sought to ascertain whether concurrent determination of mucosal disaccharidase activities and histologic assessment improves the accuracy of diagnosis of rejection. Histologic changes were graded blindly using a standard set of diagnostic criteria, and these changes were compared over time to maltase, sucrase, lactase, and palatinase activities in four pediatric patients under treatment for severe rejection. The histologic criteria, which included magnitude of enterocyte loss, degree of granulation tissue, severity of villus atrophy, and frequency of apoptosis and cryptitis, were found to correlate with one another over time irrespective of outcome (r = 0.72 to r = 0.85). Enzyme activities were also correlated with each other over time (r = 0.64 to r = 0.80). However, the correlation between histologic diagnosis and enzyme activity was weaker (r = -0.48 to r = -0.57). Furthermore, neither histologic nor enzyme evaluation early in the course of rejection predicted ultimate clinical outcome. The results of this investigation show that determination of mucosal disaccharidase activity provides no additional useful information concerning efficacy of anti-rejection therapy as compared to histologic analysis alone.

Child↗
PubMed1997

Treatment of surgically induced acute liver failure by transplantation of conditionally immortalized hepatocytes.

The shortage of human livers available for hepatocyte isolation limits its clinical application. The availability of cloned, conditionally immortalized hepatocytes that could be grown in culture but would lose their transformed phenotype and provide metabolic support upon transplantation would greatly facilitate the treatment of acute liver failure. Toward this goal, we transduced isolated Lewis rat hepatocytes using a replication-defective recombinant retrovirus capable of transferring a gene encoding a thermolabile mutant simian virus 40 T antigen (SV40ts). The cloned, immortalized hepatocytes proliferate at 33 degrees C. At the nonpermissive temperatures (37-39 degrees C), they stop growing and exhibit characteristics of differentiated hepatocytes. These cells did not produce tumors when transplanted in mice with severe combined immunodeficiency disease or in syngeneic rats. To induce acute liver failure, Lewis rats were subjected to 90% hepatectomy (Hpx) and given 5% oral dextrose. All rats that did not undergo hepatocyte transplantation died within 96 hr. Fifty percent of rats that received intrasplenic injection of 10 x 10(6) primary Lewis rat hepatocytes (G2, n=6) or 10 x 10(6) SV40ts-conditionally immortalized (SV40ts-ci) hepatocytes (G3, n=8) 1 day before 90% hepatectomy survived, whereas 80% of rats that received an intraperitoneal injection of 200 x 10(6) primary Lewis rat hepatocytes (G4, n=10) or 200 x 10(6) SV40ts-ci hepatocytes (G5, n=10) on the day of hepatectomy survived. Survival after intraperitoneal injection of a cellular homogenate of 200 x 10(6) primary Lewis rat (G7, n=9) or SV40ts-ci hepatocytes (G8, n=10) on the day of Hpx was 33% and 40%, respectively, whereas survival after intraperitoneal injection of 200 x 10(6) Lewis rat bone marrow cells (G6, n=7) was 29%. Thus, transplanted, conditionally immortalized hepatocytes can be as effective as primary hepatocytes in supporting life during acute liver insufficiency. This work represents the first step in developing an hepatocyte cell line that would partially alleviate the organ-donor shortage and could be of potential clinical value.

Animals↗
PubMed1997

Long-term follow-up of auxiliary orthotopic liver transplantation for the treatment of fulminant hepatic failure.

BACKGROUND: Auxiliary orthotopic liver transplantation (AOLT) was investigated as a bridge to native liver recovery in patients with fulminant hepatic failure (FHF). METHODS: In the last 5 years seven patients with FHF were treated with AOLT at our institution. Five patients underwent resection of the native left lobe and orthotopic replacement with a donor left lobe (n = 3) or left lateral segment (n = 2). Two patients underwent left trisegmentectomy and whole liver auxiliary grafting. Conventional immunosuppression was used in all patients. RESULTS: One patient had poor initial graft function and required retransplantation. Native liver function returned to normal in the six other patients. Immunosuppression was gradually tapered and completely discontinued in three patients, allowing for atrophy of the allograft. The allograft was removed in the other four patients. Despite evidence of native liver regeneration, two patients with aplastic anemia died after allograft removal. Four patients are alive at a mean follow-up of 3.5 years. CONCLUSIONS: AOLT is technically feasible, rapidly restores liver function, and should be considered an important alternative to standard orthotopic liver transplantation (OLT) in the treatment of FHF. AOLT has the advantage that patients transplanted for FHF are not committed to lifelong immunosuppression with its attendant risks.

Adolescent↗
PubMed1996

Use of gene therapy to suppress the antigen-specific immune responses in mice to an HLA antigen.

Hematopoietic chimerism has been used in the laboratory to induce life-long immunologic tolerance to donor antigens. The present study demonstrates that mice transplanted with autologous bone marrow cells retrovirally transduced to express HLA-A2.1 develop a significantly depressed immune response to this antigen while retaining normal reactivity to HLA-B7. Retrovirus-mediated transduction was performed using whole bone marrow-producer cell coculture. This approach did not result in significant gene transfer into hematopoietic progenitor cells. Despite this, the antibody response to HLA-A2.1 in mice reconstituted with genetically modified BMC was completely suppressed three months following bone marrow transplantation. Cell-mediated immunity to HLA-A2.1 was partially suppressed in three-fourths of animals tested three months later, although one animal had a CTL profile similar to that an of HLA-A2.1 transgenic mouse. Complete suppression of the antibody-mediated immune response occurred when only one-third of mice had evidence of the introduced genes in their spleen and one-tenth had the introduced sequences in their circulating WBCs by PCR. In conclusion, engineering of BMC to express donor MHC genes may be an alternative to xenogeneic BMT to induce chimerism and tolerance. More efficient transduction of bone marrow progenitor cells may result in more persistent gene expression and long-lasting transplantation tolerance in recipients of genetically modified bone marrow. Successful application of this technology may also be useful in altering immune responses to other external and self antigens.

Animals↗
PubMed1996

Combined liver/small bowel transplantation using a blood group compatible but nonidentical donor.

A successful liver/small intestinal transplantation with a blood group O donor to a blood type A recipient is described. Mild graft versus host disease developed, manifested by hemolysis, but did not result in graft loss or patient mortality. This suggests that minor ABO incompatibility may be tolerated with intestinal transplantation, despite the transplantation of large amounts of lymphoid tissue.

ABO Blood-Group System↗
PubMed1996

Transplantation of conditionally immortalized hepatocytes to treat hepatic encephalopathy.

Transplantation of hepatocytes has been shown to provide metabolic support during liver failure in experimental models. The potential clinical application of hepatocyte transplantation, however, is limited by the need for readily available, well-characterized cells, and a worldwide shortage of donor organs. A clonal hepatocyte cell line that could be grown economically in vitro and would exhibit a differentiated, nontransformed phenotype following transplantation would be an attractive solution to this problem. To test this alternative, primary Lewis rat hepatocytes were conditionally immortalized by retroviral transduction with a thermolabile mutant Simian virus 40 (SV40) large T antigen. The cloned immortalized cells proliferate in culture at 33 degrees C and stop growing at 37 degrees C to 39 degrees C. Transplanted into normal livers, these hepatocytes integrate normally into liver cords. When transplanted into the spleens of portacaval-shunted rats, they protect recipients from hyperammonemia-induced hepatic encephalopathy. The cells engrafted in the spleen exhibit normal morphology, secrete bile, and express albumin messenger RNA. The protection from hyperammonemia is reversed by splenectomy. These studies show that hepatocytes can be conditionally immortalized, expanded in culture, and are capable of providing metabolic support in chronic liver insufficiency. Safeguards that could make these cells clinically useful can be accomplished using currently available technology.

Animals↗
PubMed1996

Morbidity in patients with posttransplant diabetes mellitus following orthotopic liver transplantation.

It is not well understood whether posttransplant diabetes mellitus (PTDM) following orthotopic liver transplantation (OLTx) alters postoperative morbidity. This study was designed to evaluate this question. All adult patients who received an OLTx between July 1985 and March 1993 (n = 497) were evaluated by retrospective chart review for evidence of PTDM after OLTx. The patients identified with PTDM (n = 26) were case matched with nondiabetic OLTx recipients based on primary liver disease diagnosis, age, gender, date of first OLTx, and survival. Liver synthetic function, number and severity of rejection episodes, graft survival, total number of hospital days within the first year post-OLTx, renal function, and number and type of infection episodes were analyzed to assess differences in morbidity between the PTDM and control patients after OLTx. Of the 497 adult patients who underwent OLTx, 26 (5.2%) were identified as having PTDM within 1 month of discharge. Factors which identified individuals at higher risk for DM after OLTx included higher pre-OLTx fasting blood glucose (P = .04); lower body mass index after OLTx (P = .02); and cyclosporine rather than OKT3 induction (P = .009). Graft survival, synthetic function, and the total number of rejection episodes during the first year were not different between the two groups. The morbidity variables of total number of days in the hospital during the first 12 months, renal function, and type and number of infections were also similar between the two groups. In summary, 5.2% of adult patients developed DM within 1 month of OLTx. Pre-existing insulin resistance, postoperative stress, and immunosuppression medications all likely contribute to the development of overt hyperglycemia after OLTx. Although PTDM can be a consequence of OLTx, it does not have a significant impact on patient outcome in the first year after OLTx.

Adult↗
PubMed1996

Preliminary experience with intestinal transplantation in infants and children.

OBJECTIVE: This report discusses the preliminary experience with intestinal transplantation in children at the University of Nebraska Medical Center. PATIENTS: During the past 4 years, 16 intestinal transplants have been performed in infants and children. Thirteen have been combined liver and bowel transplants, and the reminder were isolated intestinal transplants. Nearly half of the patients were younger than 1 year of age at the time of surgery, and the vast majority were younger than 5 years of age. All but one had short bowel syndrome. RESULTS: The 1-year actuarial patient and graft survival rates for recipients of liver and small bowel transplants were 76% and 61%, respectively. Eight of 13 patients who received liver and small bowel transplants remain alive at the time of this writing, with a mean length of follow-up of 263 (range, 7 to 1223) days. Six patients are currently free of total parenteral nutrition. All three patients receiving isolated intestinal transplants are alive and free of parenteral nutrition. The mean length of follow-up is 384 (range, 330 to 450) days. Major complications have included severe infections and rejection. Lymphoproliferative disease, graft-versus-host disease, and chylous ascites have not been major problems. CONCLUSIONS: Although intestinal transplantation is in its infancy, these preliminary results suggest combined liver and bowel transplants and isolated intestinal transplantation may be viable options for some patients with intestinal failure caused by short bowel syndrome or other gastrointestinal disease in whom long-term total parenteral nutrition is not an attractive option.

Actuarial Analysis↗
PubMed1995

Procurement and preparation of human isolated small intestinal grafts for transplantation.

We have developed a donor operation that incorporates en bloc removal of the liver and intestine with a limited surgical resection in vivo. Over the past 18 months, we have used the following technique for the retrieval and preparation of seven isolated small intestinal allografts. The donor operation and bench preparation can be divided into three phases. During the first phase, the small intestine is removed with the liver, pancreas, and an aortic segment. In the second phase performed ex vivo, the donor liver can be separated from the specimen. The third phase involves additional bench dissection to yield an isolated intestinal allograft. The principle advantage of this technique is that it reduces potential liver injury by minimizing the surgical dissection required in vivo. Also, dividing the liver from the intestine ex vivo allows the organs to be separated in a bloodless field under controlled conditions that may be especially important when two different surgical teams are involved.

Dissection↗
PubMed1995

Low incidence of intraspousal transmission of hepatitis C virus after liver transplantation.

Although the incidence of spousal transmission of hepatitis C virus (HCV) in chronic carriers is extremely low (1.4% to 8%), hepatitis C recurrence after liver transplantation is common with markedly increased serum HCV RNA levels. Thus, partners of these patients may be at higher risk of acquiring infection. This study evaluates the prevalence of spousal transmission of hepatitis C after liver transplantation. Twenty-two of 25 couples who were eligible agreed to the retrospective study. Twenty-two patients (17 males, 5 females) and spouses (5 males, 17 females) were studied with respective mean ages of 50.2 years (35 to 65 years) and 46.9 years (33 to 66 years). Liver enzymes, second-generation enzyme-linked immunosorbent assay (ELISA) for antibody to HCV (anti-HCV) and HCV RNA by polymerase chain reaction (PCR), and branched DNA assay were performed. HCV-associated antibodies were detected in 1 of 22 (5%) spouses and 21 of 22 (95%) patients (P < .0001). Nineteen of 22 (86%) patients tested positive by PCR with a mean value of 16,218,100 Eq/mL (464,700 to 51,980,000). All spouses including the only ELISA anti-HCV positive spouse tested negative by PCR (P < .0001). Eight of 21 spouses tested negative for anti-HCV pretransplantation, (13 of 21 pretransplantation were not tested). Estimated mean duration of hepatitis C infection in patients was 14 years (3 to 40 years). Mean patient follow-up posttransplantation was 654.5 days (141 to 1,959 days). Mean duration of marriage was 22.6 years (2.5 to 46 years). No risk factors other than exposure to index patients were observed in spouses. The incidence of spousal transmission of HCV in liver transplantation remains low (5%) and similar to chronic carriers of HCV.

Adult↗
PubMed1995

Proton spectroscopy of brain glutamine in acute liver failure.

Evidence indicates that the accumulation of glutamine in the brain plays an important role in the pathogenesis and severity of the encephalopathy of acute liver failure (ALF). This study uses in vivo proton magnetic resonance spectroscopy (1H MRS) to assess brain glutamine (GLN) in five cases of acute liver failure. The findings are consistent with prior investigations and suggest that the alpha 1H of the GLN molecule can be used for noninvasive spectroscopic quantitation of brain GLN in patients with ALF.

Acute Disease↗
PubMed1995

Conditional immortalization of Gunn rat hepatocytes: an ex vivo model for evaluating methods for bilirubin-UDP-glucuronosyltransferase gene transfer.

Viral vectors and protein carriers utilizing asialoglycoprotein receptor (ASGR)-mediated endocytosis are being developed to transfer genes for the correction of bilirubin-UDP-glucuronosyltransferase (bilirubin-UGT) deficiency. Ex vivo evaluation of these gene transfer vectors would be facilitated by a cell system that lacks bilirubin-UGT, but expresses differentiated liver functions, including ASGR. We immortalized primary Gunn rat hepatocytes by transduction with a recombinant Moloney murine leukemia virus expressing a thermolabile mutant SV40 large T antigen (tsA58). At 33 degrees C, the immortalized hepatocyte clones expressed SV40 large T antigen, synthesized DNA, and doubled in number every 2 to 3 days. At this temperature, differentiated hepatocyte markers, e.g., albumin, ASGR, and androsterone-UGT, were expressed at 5% to 10% of the levels found in primary hepatocytes maintained in culture for 24 hours. Glutathione-S-transferase Yp (GST-Yp), an oncofetal protein, was expressed in these cells at 33 degrees C, but was undetectable in primary hepatocytes. In contrast, when the cells were cultured at 39 degrees C or 37 degrees C, the large T antigen was degraded, DNA synthesis and cell growth stopped, and morphologic characteristics of differentiated hepatocytes were observed. The expression of albumin, ASGR, and androsterone-UGT, and their corresponding mRNAs, increased to 25% to 40% of the level in primary hepatocytes, whereas GST-Yp expression decreased. Functionality of ASGR was demonstrated by internalization of Texas red-labeled asialoorosomucoid, and binding and degradation of 125I-asialoorosomucoid. After liposome-mediated transfer of a plasmid containing the coding region of human bilirubin-UGT1, driven by the SV40 large T promoter, active human bilirubin-UGT1 was expressed in these cells. The immortalized cells were not tumorigenic after transplantation into severe combined immunodeficiency mice. These conditionally immortalized cells will be useful for ex vivo evaluation of bilirubin-UGT gene transfer vectors.

Animals↗