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J M Neuberger

Publications and source records attributed to J M Neuberger.

At least 37 records · Page 2Linked to original sources
PubMed1996

Random phage mimotopes recognized by monoclonal antibodies against the pyruvate dehydrogenase complex-E2 (PDC-E2).

Dihydrolipoamide acetyltransferase, the E2 component of the pyruvate dehydrogenase complex (PDC-E2), is the autoantigen most commonly recognized by autoantibodies in primary biliary cirrhosis (PBC). We identified a peptide mimotope(s) of PDC-E2 by screening a phage-epitope library expressing random dodecapeptides in the pIII coat protein of fd phage using C355.1, a murine monoclonal antibody (mAb) that recognizes a conformation-dependent epitope in the inner lipoyl domain of PDC-E2 and uniquely stains the apical region of bile duct epithelium (BDE) only in patients with PBC. Eight different sequences were identified in 36 phage clones. WMSYPDRTLRTS was present in 29 clones; WESYPFRVGTSL, APKTYVSVSGMV, LTYVSLQGRQGH, LDYVPLKHRHRH, AALWGVKVRHVS, KVLNRIMAGVRH and GNVALVSSRVNA were singly represented. Three common amino acid motifs (W-SYP, TYVS, and VRH) were shared among all peptide sequences. Competitive inhibition of the immunohistochemical staining of PBC BDE was performed by incubating the peptides WMSYPDRTLRTS, WESYPDRTLRTS, APKTYVSVSGMV, and AALWGVKVRHVS with either C355.1 or a second PDC-E2-specific mAb, C150.1. Both mAbs were originally generated to PDC-E2 but map to distinct regions of PDC-E2. Two of the peptides, although selected by reaction with C355.1, strongly inhibited the staining of BDE by C150.1, whereas the peptide APKTYVSVSGMV consistently inhibited the staining of C355.1 on biliary duct epithelium more strongly than the typical mitochondrial staining of hepatocytes. Rabbit sera raised against the peptide WMSYPDRTLRTS stained BDE of livers and isolated bile duct epithelial cells of PBC patients more intensively than controls. The rabbit sera stained all size ducts in normals, but only small/medium-sized ductules in PBC livers. These studies provide evidence that the antigen present in BDE is a molecular mimic of PDC-E2, and not PDC-E2 itself.

Amino Acid Sequence↗
PubMed1996

Effect of liver transplantation on QT interval prolongation and autonomic dysfunction in end-stage liver disease.

Both a prolonged QT interval and disturbance of autonomic nervous system function are markers of poor prognosis in patients with diabetes mellitus and alcoholic liver disease (ALD). We studied the prevalence of abnormal QT interval and autonomic nervous system dysfunction in 53 consecutive patients with end-stage liver disease before and after orthotopic liver transplantation (OLT). The maximum QT interval in any lead (QTmax) was assessed by two independent observers. The QTmax, corrected for heart rate (QTcmax) was prolonged in 44 patients (83%), although increased QT dispersion was not found. There was a significant correlation between the QTcmax and Child-Pugh score but not with etiology. Evidence of parasympathetic dysfunction was present in 41 patients (77%), and sympathetic dysfunction was present in 20 patients before OLT. Fifty-two patients underwent transplantation. There was significant improvement in the QTcmax interval after OLT (P < .001); 32 of the 44 patients with prolonged QTcmax ( > 440 milliseconds) improved. Repeat testing was not performed in 7 patients, because they had died or had not undergone transplantation. Indices of parasympathetic function improved in 27 patients after OLT, but no improvement was observed in 8. Improvement in sympathetic dysfunction was observed in 13 of the 19 patients tested. There was no association between QTcmax, autonomic dysfunction, and survival. These results suggest that both prolonged QTcmax and some tests of autonomic function are temporary and arise as a consequence of liver dysfunction.

Adolescent↗
PubMed1996

Inhibition of PDC-E2 human combinatorial autoantibodies by peptide mimotopes.

Immunohistochemical studies have shown that a unique immunoreactive molecule is present near the apical region of human biliary epithelial (BE) cells in patients with primary biliary cirrhosis (PBC). This can be visualized by confocal microscopy in PBC livers using a number of unique monoclonal antibodies to the E2 component of pyruvate dehydrogenase complex (PDC-E2), the autoantigen most commonly recognized by antimitochondrial antibodies (AMA). One such antibody, the murine mAb C355.1 was used to identify peptide mimotopes of PDC-E2 by screening a random dodecapeptide phage library ON 159.2 to identify the possible biochemical nature of this apical staining molecule. Out of 36 independent clones, 29 showed a common sequence and seven other sequences were singly represented. Three common amino acid motifs (SYP, TYVS and VRH) were found among these eight sequences. Similar to C355.1, the human combinatorial antibodies derived from a patient with PBC, SP1 and SP4, recognize the inner lipoyl domain of PDC-E2. However, when these antibodies are used to stain PBC BE cells, SP4 stains the apical region of PBC BE cells with high intensity whereas SP1 produces only cytoplasmic staining. Competitive inhibition of immunohistochemical staining using PDC-E2 specific human combinatorial antibodies SP1 and SP4 was performed using five of the above dodecapeptides. Interestingly, the peptides selected with C355.1 differentially inhibited the binding of SP1 and SP4 to PBC BE cells. Finally, rabbit sera raised against one such peptide (WMSYPDRTLRTS) stained BE cells from patients with PBC with a higher intensity than controls. Comparable data was obtained with immunoelectronmicroscopy. These data suggest that a molecular mimic of PDC-E2 is present at the external aspect of PBC BE cells.

Amino Acid Sequence↗
PubMed1996

Recurrence of primary biliary cirrhosis in the liver allograft: the effect of immunosuppression.

BACKGROUND: Recurrence of primary biliary cirrhosis in the liver allograft remains controversial. METHODS: We have examined the liver allograft biopsies taken at 1 and 2 years after transplantation from patients receiving either FK506 or cyclosporin as part of a multi-centre trial. RESULTS: Histological features characteristic for primary biliary cirrhosis, including bile duct damage, ductopenia, bile duct proliferation and portal granulomas, were found more commonly and earlier after transplantation in patients receiving FK506 than cyclosporin. During the 2-year period, seven of 16 patients receiving FK506 and only one of 11 on cyclosporin had a graft biopsy suggestive of recurrent primary biliary cirrhosis. CONCLUSIONS: These findings confirm earlier reports that features of primary biliary cirrhosis recur in the liver allograft in some patients and suggest that the rate of recurrence may be affected by the immunosuppression regimen used.

Adult↗
PubMed1996

End-stage primary biliary cirrhosis in a first generation migrant south Asian population.

Primary biliary cirrhosis (PBC) is uncommonly described from Asia and it is an extremely rare cause of chronic liver disease in India. Six first generation migrant Asian patients with PBC were seen at the Liver Unit, Queen Elizabeth Hospital, Birmingham during the period 1982-94. All were women and their ages at presentation ranged from 31 to 63 (median 40) years. All were symptomatic for a median of 6 months prior to referral to the unit for transplantation. Itching with or without jaundice was a common presenting feature. Diagnosis was based on raised serum IgM levels, presence of antimitochondrial antibody (titres 100-400) and diagnostic histology. Only one patients had an associated autoimmune disease (coeliac disease). Serum bilirubin level was above 100 mumol/l at the time of presentation in four patients. Four of these patients with end-stage PBC are first generation migrants from south Asia, who have been resident in the West Midlands for the past 10 to 34 years. The total south Asian population of the West Midlands is 276,754; thus, from these four patients alone the estimated prevalence of PBC in the migrant south Asian population is at least 14 per million. However, such data cannot be used to give any accurate assessment of prevalence, for which a population screening programme is required. A higher incidence in the migrant population than in their countries of origin is compatible with an environmental aetiology.

Adult↗
PubMed1995

Timing, significance, and prognosis of late acute liver allograft rejection.

Liver allograft rejection is usually divided into acute (cellular) rejection and chronic (ductopenic) rejection. Most cases of acute rejection occur within four weeks of transplantation. There is a paucity of published literature on late acute rejection (LAR) in liver allografts and little is known about factors affecting its occurrence and outcome. To study the predisposing factors, clinical presentation, and prognosis of LAR, data prospectively collected on consecutive adult patients who underwent liver transplantation between 1982 and 1994, were analyzed. LAR was defined as histologically confirmed acute cellular rejection occurring 30 or more days after liver transplantation. Of the 717 patients, 59 (7.5%) had 71 episodes of LAR. Fifty-seven episodes were seen during the first year after transplantation, the remaining occurring between 1 and 6 years. Age, sex, pretransplant diagnosis, donor match of HLA, and blood groups was not associated with risk of LAR. Twenty-seven (38%) episodes were preceded by subtherapeutic blood levels of cyclosporine/FK506 (< 100 ng/ml and < 5 ng/ml, respectively) while an additional 6 (8%) had marginally low blood levels (< 150 ng/ml and < 10 ng/ml, respectively). Treatment with high-dose prednisolone resulted in complete resolution of rejection in 36 (51%) episodes, partial response in 21, and no response in 14 patients. Sixteen patients (27%) developed chronic rejection and graft loss. Development of chronic rejection was not affected by age or sex of the patient, timing of LAR, or histological severity of AR. Delayed response to therapy during an earlier episode of AR, and histological findings of centrilobular necrosis or bile duct loss at the time of diagnosis of LAR were associated with high risk of progression to chronic rejection and graft loss.

Adolescent↗
PubMed1995

Sex mismatch as a risk factor for chronic rejection of liver allografts.

Chronic irreversible rejection is a major cause of graft loss and retransplantation after orthotopic liver allotransplantation. To identify risk factors we retrospectively analysed 423 adult consecutive primary liver allograft recipients. The endpoint of the study was graft failure due to chronic rejection leading either to retransplantation or death. Chronic rejection developed in 22 (5.2%) patients. Pretransplant diagnosis of primary biliary cirrhosis or autoimmune hepatitis, recipient age less than 30 years, 1 or more episodes of acute cellular rejection, and transplantation of an organ from cytomegalovirus (CMV). IgG positive donor to an IgG negative recipient were identified as risk factors for chronic rejection. Transplantation of a liver from a male donor into a female recipient was also associated with an increased probability of chronic rejection. By logistic regression analysis, the probability of chronic rejection was predicted by: sex and cytomegalovirus match of donor and recipient, the presence of acute rejection, recipient age, transplantation for autoimmune hepatitis or primary biliary cirrhosis, and recipients receiving no azathioprine during the third month after transplantation. Sensitisation to antigens expressed by bile-duct epithelium as in primary biliary cirrhosis or exposure to donor bile-duct minor histocompatibility antigens, such as the male sex related H-Y antigen, may provide an explanation. More selective allocation of donor organs may allow a reduction in the incidence of ductopaenic rejection and graft loss.

ABO Blood-Group System↗
PubMed1995

Apoptosis in the human liver during allograft rejection and end-stage liver disease.

The contribution of apoptosis (programmed cell death) to cellular damage in human liver disease is unknown. Using the in situ DNA end labelling method (ISEL), evidence was sought of programmed cell death (PCD) in liver tissue from patients with various liver diseases. In particular, the study aimed to determine whether PCD is involved in either the loss of interlobular bile ducts (vanishing bile duct syndrome--VBDS) or the perivenular hepatocyte drop-out, both of which are characteristic of irreversible graft rejection. Large numbers of apoptotic hepatocytes were found in perivenular areas in tissues taken from patients with chronic graft rejection. Significant hepatocyte apoptosis, was not seen in long-term stable allografts, primary biliary cirrhosis, cholestasis, paracetamol-induced fulminant hepatic failure, or fulminant hepatic failure of indeterminate origin (non-A, non-B, non-C hepatitis). Bile ducts rarely stained positively, but mononuclear cells present in the post-transplant tissues were frequently positive, showing nuclear or cytoplasmic staining. The presence of cytoplasmic staining suggested that some mononuclear cells had ingested apoptotic DNA from other cellular sources. PCD may thus contribute to the perivenular hepatocyte loss in chronic rejection. The absence of ductular epithelial cell staining suggests that PCD is not involved significantly in the bile duct loss of VBDS. Furthermore, apoptosis of mononuclear cells implies that PCD may be involved in regulating the inflammatory cell infiltration of graft rejection.

Apoptosis↗
PubMed1995

Subcellular localization of pyruvate dehydrogenase dihydrolipoamide acetyltransferase in human intrahepatic biliary epithelial cells.

In previous histological studies, biliary epithelial cells (BEC) in the liver of patients with primary biliary cirrhosis (PBC), but not controls, reacted strongly with antibodies specific for the major autoantigen associated with PBC, the E2 component of pyruvate dehydrogenase complex (PDC-E2). In this study we have used transmission electron microscopy (TEM) to document the precise subcellular localization of PDC-E2 in BEC. Two antibodies which recognize PDC-E2 were used: affinity-purified anti-PDC-E2 raised in rabbits; and human antibody from the serum of patients with PBC, affinity-purified against human heart PDC. The intracellular localization of antibody binding was determined by laser scanning confocal microscopy and TEM. Both antibodies bound to the inner membrane of mitochondria in BEC isolated from both patients with PBC and controls, but binding to the external aspect of the plasma membrane was observed only in BEC from patients with PBC. Surface antigen expression in PBC may make BEC immunological targets.

Adult↗
PubMed1995

Hepatitis C virus infection in the asymptomatic British blood donor.

Blood donor screening for hepatitis C virus (HCV) antibodies is now routine. Most blood transfusion services recommend that seropositive donors are referred for further investigation. Southern European studies suggest that many asymptomatic seropositive donors have clinically significant liver disease. Seropositive donors in areas of high prevalence may not, however, be representative of British donors. We have prospectively examined the prevalence and severity of HCV infection in a British volunteer blood donor population. During a 14 month period, only 0.35% (999/287,332) of all donors in the West Midlands were anti-HCV (screening assay) positive. Only 5% (52/999) of these were confirmed true seropositive. Nearly 80% (41/52) of seropositive donors were referred to the Queen Elizabeth Hospital Liver Unit for further investigation. Most underwent complete investigation, including liver biopsy. Forty of forty-one donors had biochemical, histological, or virological evidence of persistent viral infection. Histological changes were generally mild and none was cirrhotic. Covertly infected patients had less severe disease than those with an overt risk factor for HCV exposure. In the British Midlands, the prevalence of blood donor seropositivity is low. In contrast with seropositive Southern European donors, the British donor is more likely to belong to an at-risk group for parenteral exposure and is less likely to have severe histological changes. This study highlights the importance of developing locally relevant guidelines for the counselling and investigation of anti-HCV-positive blood donors.

Adult↗
PubMed1995

Characterization of biliary epithelial cells isolated from needle biopsies of human liver in the presence of hepatocyte growth factor.

Current methods for the isolation of intrahepatic biliary epithelial cells from human liver rely upon relatively large segments of tissue, thereby limiting studies to cells isolated from patients with end-stage disease. To investigate a greater range of diseases and those at an earlier stage, we have developed a method to isolate biliary epithelial cells from biopsy-sized fragments of human liver. Tissue explants are cultured for > 4 weeks, and, in approximately 50% of samples incubated with medium containing hepatocyte growth factor, biliary epithelial cells begin to migrate from the fragments and proliferate. With time they form confluent pavements of cells that express cytokeratin 19 and gamma-glutamyl transpeptidase and are negative for markers of non-biliary cell phenotype. After subculturing, cells can be expanded, yielding substantial numbers for subsequent study in vitro. Cells can be isolated with a similar degree of success from adult normal liver, from a variety of liver diseases, and from post-transplant liver biopsies. Overall, pediatric tissue yielded cells less frequently than adult tissue. This novel technique is likely to have a major impact on the study of biliary pathophysiology, as small fragments of tissue removed from biopsies taken for diagnostic purposes can be used.

Adolescent↗
PubMed1994

HLA DR4 is a marker for rapid disease progression in primary sclerosing cholangitis.

BACKGROUND/AIMS: Primary sclerosing cholangitis (PSC) is an inflammatory disease of the biliary tree associated with an increase in the HLA alleles DR3, DR52a, DR2, Dw2, and a decrease in DR4. However, it is not certain which of these alleles provides the primary associations. Our aim was to establish the primary HLA associations with PSC and to assess the ability of HLA alleles to mark for disease progression. METHODS: By applying molecular techniques to archival tissue, we have genotyped 83 PSC patients from two populations and 131 controls for the alleles HLA DR2, DR3, DR4, DRw12, DR52a, and Dw2. RESULTS: HLA DR3, DR52a, DR2, and Dw2 were all significantly increased in PSC, with the relative risk for DR52a and Dw2 being greater than for DR3 and DR2, respectively. HLA DR4 was significantly decreased, but this may be artifactual to the DR3, DR2 increase. HLA DR4 and not DR52a marks for rapid disease progression in both our PSC populations. CONCLUSIONS: HLA DR52a and Dw2 are the best candidate alleles for providing the known HLA association with PSC. HLA DR4 and not DR52a marks for rapid disease progression in our two PSC populations.

Amino Acid Sequence↗
PubMed1994

The influence of cyclosporine A therapy on sex hormone levels in pre- and post-menopausal women with primary biliary cirrhosis.

The mechanism underlying sex hormone disturbances in post-menopausal women with primary biliary cirrhosis is unclear, but these alterations may occur as a consequence of liver disease. As cyclosporine may have some therapeutic potential is this condition, we have evaluated short-term alterations in plasma sex hormone levels in 11 pre- and 19 post-menopausal women with primary biliary cirrhosis following randomisation to cyclosporine A or placebo therapy. Baseline sex hormone binding globulin levels were markedly depressed in all pre-menopausal women but were elevated for the post-menopausal group when compared to standard reference ranges. Testosterone and dihydrotestosterone levels were low or markedly depressed in both patient groups. Androstendione concentrations tended to be higher than the normal range in the post-menopausal group. Oestradiol levels were within the normal range for the pre-menopausal group but were relatively higher in the post-menopausal group than in other normal post-menopausal women. Cyclosporine A therapy resulted in significant decreases in sex hormone binding globulin levels (26.6 +/- 5.0 to 16.2 +/- 4.6 nmol/l; p < 0.05) in the premenopausal group and reduction in total (336 +/- 163 to 140 +/- 132 pmol/l; p < 0.01) and free (6 +/- 5 to 2 +/- 3 pmol/l; p < 0.05) oestradiol levels in the post-menopausal group at 6 months. There were no significant alterations in other hormonal parameters. No temporal changes occurred in the placebo group. Cyclosporine A therefore induces significant but variable sex hormone changes in both pre- and post-menopausal women with primary biliary cirrhosis.

Adult↗
PubMed1994

Serious paracetamol poisoning and the results of liver transplantation.

Paracetamol poisoning is the most common cause of fulminant liver failure in the United Kingdom. An accurate assessment of prognosis at the time of referral will allow the appropriate application of liver transplantation in this setting. The outcome of 92 patients consecutively admitted to a specialist liver unit with severe poisoning has been examined. In patients who did not have a transplant, a fatal outcome was seen for 26/82 (32%), and was associated with late presentation, coma grade, prothrombin time prolongation, metabolic acidosis, and renal dysfunction. Cerebral oedema, and sepsis were responsible for most deaths. Prognostic criteria defined at King's College Hospital seemed to predict the outcome of patients who did not have a transplant managed on the Birmingham liver unit. Seventeen patients were listed for transplantation, 10 had liver transplantation, and seven of 10 survived. Seven were listed but not transplanted, and one of seven survived. Psychological rehabilitation of patients who had a transplant has not proved difficult. These results suggest a role for liver transplantation in the management of selected patients with paracetamol poisoning.

Acetaminophen↗
PubMed1994

Effects of a computerised protocol management system on ordering of clinical tests.

OBJECTIVE: To assess the effects of a computerised protocol management system on the number, cost, and appropriateness of laboratory investigations requested. DESIGN: A before and after intervention. SETTING: A supraregional liver unit in a teaching hospital. PATIENTS: 1487 consecutive patients admitted during 1990 and 1991 (one year before and one year after introduction of the system). INTERVENTION: Introduction of a computerised protocol management system on 1 January 1991. MAIN MEASURES: The number and cost of clinical chemistry tests requested per patient day. RESULTS: The total number of clinical chemistry tests requested per patient day by the unit declined 17% (p < 0.001, Student's t test) and of out of hours tests requested per patient day from 0.31 to 0.16, 48% (p < 0.001; Mann-Whitney U test), resulting in a 28% reduction (p < 0.001) in direct laboratory expenditure per patient-day. Overall, the number of tests per admission decreased by 24% (p < 0.001; Mann-Whitney U test). CONCLUSION: Use of the computerised protocol management system resulted in closer compliance with the protocols and a significant reduction in the overall level of requesting. IMPLICATIONS: Although similar systems need to be tested in other clinical settings, computerised protocol management systems may be important in providing appropriate and cost effective health care.

Clinical Laboratory Techniques↗
PubMed1994

Fibrous and obliterative cholangitis in liver allografts: evidence of recurrent primary sclerosing cholangitis?

Fibroobliterative lesions and fibrous cholangitis are characteristic histological lesions of primary sclerosing cholangitis. To determine whether such lesions can be found in the liver allograft, and whether they represent recurrent disease, we reviewed all consecutive histological material taken at greater than 6 mo after transplantation in a 3-yr period from a series of 207 liver transplantations (22 with primary sclerosing cholangitis, 185 controls without primary sclerosing cholangitis). Because patients with primary sclerosing cholangitis have a biliary system reconstructed by means of a Roux loop, we compared the findings with those from a further control group of patients who had received a Roux loop for reasons other than primary sclerosing cholangitis. Of 22 patients receiving liver transplants for primary sclerosing cholangitis, 7 (32%) patients had biopsy specimens showing features of biliary obstruction, 6 (27%) showed fibrous cholangitis, and 3 (14%) showed classic fibroobliterative lesions. These findings compared with 3 (14%), 1 (5%) and 0 of 22 Roux controls, and 19 (10%), 4 (2%) and 0 of 185 controls without primary sclerosing cholangitis, respectively. The three patients with fibroobliterative lesions either had clinical episodes of cholangitis or had microorganisms in the large bile ducts. However, both biliary obstructive features and fibrous cholangitis were more common in primary sclerosing cholangitis, and fibroobliterative lesions were found only in patients who received transplants for primary sclerosing cholangitis, despite the presence of cholangitis and Roux loops in control patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Distribution of pyruvate dehydrogenase dihydrolipoamide acetyltransferase (PDC-E2) and another mitochondrial marker in salivary gland and biliary epithelium from patients with primary biliary cirrhosis.

Previous studies in which quantitative immunofluorescence was used have shown that certain biliary epithelial cells in liver with primary biliary cirrhosis show increased levels of pyruvate dehydrogenase dihydrolipoamide acetyltransferase compared with controls. This study was designed to determine whether the increase in intensity of pyruvate dehydrogenase dihydrolipoamide acetyltransferase in biliary epithelial cells is accounted for by an increase in the number of mitochondria in the same cells. A double-antibody staining technique was used with antibodies specific for pyruvate dehydrogenase dihydrolipoamide acetyltransferase and another mitochondrial inner membrane marker, recognized by the mouse monoclonal antibody MCA151A. Distribution of the antigens was studied in sections of liver and salivary gland, an additional site that is frequently involved in primary biliary cirrhosis. Confocal microscopy was used to quantify the intensity of fluorescence resulting from binding of fluorochrome-labeled antibody. In both liver and salivary glands MCA151A binding was similar in normal and sections with primary biliary cirrhosis and corresponded to the predicted distribution of mitochondria in these tissues. In the liver staining was less intense in biliary epithelial cells than in hepatocytes. In salivary gland binding of both antibodies was predominantly localized to duct cells, with those forming striated ducts, known to be rich in mitochondria, being most intensely stained. There was high coincidence of the two antigens in salivary glands (p < 0.01) and in biliary epithelial cells from normal liver (p = 0.01). However, in liver with primary biliary cirrhosis, despite high coincidence between the antigens on hepatocytes, biliary epithelial cells showed high intensity of pyruvate dehydrogenase dihydrolipoamide acetyltransferase but not MCA151A.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗