The Voronoi theory of the normal liver lobular architecture and its applicability in hepatic zonation

The precise characterization of the lobular architecture of the liver has been subject of investigation since the earliest historical publications, but an accurate model to describe the hepatic lobular microanatomy is yet to be proposed. Our aim was to evaluate whether Voronoi diagrams can be used to describe the classic liver lobular architecture. We examined the histology of normal porcine and human livers and analyzed the geometric relationships of various microanatomic structures utilizing digital tools. The Voronoi diagram model described the organization of the hepatic classic lobules with overall accuracy nearly 90% based on known histologic landmarks. We have also designed a Voronoi-based algorithm of hepatic zonation, which also showed an overall zonal accuracy of nearly 90%. Therefore, we have presented evidence that Voronoi diagrams represent the basis of the two-dimensional organization of the normal liver and that this concept may have wide applicability in liver pathology and research.

Is histological diagnosis of primary liver carcinomas with fibrous stroma reproducible among experts?

AIMS

In the era of targeted therapeutics, histological typing of hepatobiliary carcinomas has major clinical implications. Little is known about the reproducibility of the pathological diagnosis of primary liver carcinomas. Therefore, this study aimed to evaluate the worldwide variation in the pathological expert diagnoses of primary liver carcinomas with fibrous stroma in patients who did not have cirrhosis.

METHODS

A single set of slides was selected from 25 tumours, and this set was reviewed independently by 12 pathologists who have worldwide expertise in liver tumours. Reproducibility of the diagnoses was evaluated by Light's kappa, and diagnoses were clustered by multidimensional scaling. Immunohistochemistry was performed after histological review.

RESULTS

The interobserver reproducibility for diagnosis of hepatocellular carcinoma subtypes and cholangiocarcinomas was poor (kappa 0.23-0.52), even when the experts considered that the diagnosis required no additional stains or clinical information. Interestingly, multidimensional scaling revealed three main clusters of tumours: hepatocellular carcinoma with no other specifications (n = 13), fibrolamellar hepatocellular carcinoma (n = 3) and cholangiocarcinoma (n = 9). Using immunohistochemistry, these histological clusters correlated with expression of anti-hepatocyte and anti-cytokeratin 19 (p<0.001).

CONCLUSIONS

The results demonstrate the poor reproducibility among experts of the pathological diagnosis of primary liver carcinomas with fibrous stroma in patients who did not have cirrhosis, and highlight that the systematic use of immunohistochemistry may improve the diagnostic accuracy.

An early lesion in hepatic carcinogenesis: loss of heterozygosity in human cirrhotic livers and dysplastic nodules at the 1p36-p34 region

Loss of heterozygosity (LOH) of chromosome 1 has been suggested, by karyotyping, to be an initial episode in human hepatocarcinogenesis. However, this alteration has not yet been investigated in cirrhotic nodules (CNs) or dysplastic nodules (DNs). In an initial study from explanted or resected cirrhotic livers, LOH in 1p36-p32 was examined in 31 hepatocellular carcinomas (HCCs), 25 low-grade dysplastic nodules (LGDNs), and 24 high-grade dysplastic nodules (HGDNs). In HCCs, LOH was detected most frequently at loci D1S2843 (1p36.1) (28.6%), D1S513 (1p34.3) (29.2%), and MYCL1 (1p34.1) (28.6%). In HGDN and LGDN, LOH incidences at D1S513 were 11.1% and 13.6%, respectively. To further refine those results and to determine sequential relationships among CN, DN, and HCC, LOH was next studied in an additional 53 HCCs, 56 HGDNs, 30 LGDNs, and 215 CNs from 11 explanted human cirrhotic livers, including 30 "nodule-in-nodule" lesions. Seven markers between D1S2843 (1p36.12) and MYCL1 (1p34.1), and 1 each at D1S484 (1q24.1), IGF2R-3 (6q26), and TP53 (17p13.1) were used. LOH at D1S2843 and D1S513 was detected in HCCs (20.4% and 23.5%, respectively), HGDNs (7.7% and 18.5%), LGDNs (13.6% and 6.9%), and CNs surrounding either HCCs or DNs (7.4% and 8.3%). These results demonstrate that LOH at D1S2843 and D1S513 are early events in human liver carcinogenesis. Data from CN surrounding either HCCs or DN, and also nodule-in-nodule lesions, provide evidence supporting a CN-->DN-->HCC progression. Different deletion patterns from multiple HCCs and DNs suggest independent origins for carcinogenesis in the same individual.

Clinical course and biochemistry of sialuria

Sialuria is a rare inborn error of metabolism in which excessive free sialic acid (N-acetylneuraminic acid, NeuAc) is synthesized. A defect in the feedback inhibition of UDP-N-acetylglucosamine (UDP-GlcNAc) 2-epimerase by the end-product of the sialic acid synthetic pathway, CMP-NeuAc, is the mechanism underlying this overproduction. Recent evidence suggests that sialuria is an autosomal dominant disorder. Only five patients have been documented to have such an enzymatic defect. We report a longitudinal study of one of the original sialuria patients, to age 11 years. Although he has coarse features and massive hepatomegaly, he has shown normal growth and relatively normal development. Pulmonary function testing showed minimal small airway obstruction. At 11 years, he developed intermittent abdominal pain and transient transaminase elevation above his baseline. Sialuria should be considered in the differential diagnosis of a patient with a phenotype suggestive of a mucopolysaccharidosis or oligosaccharidosis in the absence of developmental regression or prominent dysostosis multiplex. We recommend close monitoring of liver and pulmonary function in sialuria patients.

Activation of the Met receptor by cell attachment induces and sustains hepatocellular carcinomas in transgenic mice

Overexpression is the most common abnormality of receptor tyrosine kinases (RTKs) in human tumors. It is presumed that overexpression leads to constitutive activation of RTKs, but the mechanism of that activation has been uncertain. Here we show that overexpression of the Met RTK allows activation of the receptor by cell attachment and that this form of activation can be tumorigenic. Transgenic mice that overexpressed Met in hepatocytes developed hepatocellular carcinoma (HCC), one of the human tumors in which Met has been implicated previously. The tumorigenic Met was activated by cell attachment rather than by ligand. Inactivation of the transgene led to regression of even highly advanced tumors, apparently mediated by apoptosis and cessation of cellular proliferation. These results reveal a previously unappreciated mechanism by which the tumorigenic action of RTKs can be mediated, provide evidence that Met may play a role in both the genesis and maintenance of HCC, and suggest that Met may be a beneficial therapeutic target in tumors that overexpress the receptor.

Utility of CD34 reactivity in evaluating focal nodular hepatocellular lesions sampled by fine needle aspiration biopsy

OBJECTIVE

To determine the patterns of CD34 reactivity in hepatocellular adenoma and focal nodular hyperplasia and to evaluate the utility of CD34 reactivity in the diagnosis of hepatocellular carcinoma.

STUDY DESIGN

Seventeen cases of well-differentiated hepatocellular carcinoma, 14 cases of cirrhosis, 9 cases of focal nodular hyperplasia and 7 cases of hepatocellular adenoma were stained with immunoperoxidase antibodies to CD34. The slides were scored according to the degree of lesional reactivity.

RESULTS

Fourteen of 17 cell blocks with hepatocellular carcinoma showed unequivocal sinusoidal or peripheral reactivity for CD34. Five of seven cases of hepatocellular adenoma and four of nine cases of focal nodular hyperplasia showed > 50% sinusoidal reactivity for CD34. All 14 cases of cirrhosis showed peripheral to no sinusoidal reactivity.

CONCLUSION

CD34 reactivity in a diffuse sinusoidal pattern can be helpful in the diagnosis of hepatocellular carcinoma. However, consideration should be given to the possibility of hepatocellular adenoma and focal nodular hyperplasia, which can also exhibit significant diffuse CD34 reactivity. In these cases, a reticulin stain may be helpful with the differential diagnosis.

Chromosomal alterations in ulcerative colitis-related and sporadic colorectal cancers by comparative genomic hybridization

Both ulcerative colitis (UC)-related and sporadic colorectal cancers are thought to evolve through a multistep process of genomic instability, accumulation of genomic alterations, and clonal expansion. This process may involve different genomic changes in UC-related cancers than in sporadic cancers because of the origin of UC-related cancers in an inflammatory field. This study was designed to define the specific genomic events occurring in UC-related cancers. Comparative genomic hybridization (CGH) was performed on 32 UC-related and 42 stage-matched sporadic colorectal cancers. The mean number of chromosomal alterations per case was similar in the UC-related and sporadic tumor groups (8.6 in UC, 8.1 in sporadic). The 2 tumor groups shared many chromosomal alterations: losses on 18q (78% UC v69% sporadic), 8p (53% v50%), 17p (44% v57%), and gains on 8q (63% v45%), 20q (44% UC v67%), and 13q (44% UC v38%). However, differences in the frequency and timing of specific alterations were observed. Chromosome 5q was lost in 56% of UC-related but in only 26% of sporadic cancers. Alterations of chromosome 8 were associated with stage progression in UC-related, but not in sporadic cancers. In contrast, 18q loss was associated with stage progression in sporadic cancers only. Thus, differences in the frequency and timing of individual chromosomal alterations suggest that genetic progression in these 2 tumor groups may follow multiple pathways.

Expression of the mucosal vascular addressin, MAdCAM-1, in inflammatory liver disease

AIMS/BACKGROUND

The integrin alpha4beta7 and mucosal addressin cell adhesion molecule-1 (MAdCAM-1) are involved in normal recirculation of lymphocytes between the blood and the tissues of the gastrointestinal tract. In this study we have examined the expression of MAdCAM-1 in human liver.

METHODS

MAdCAM-1 expression was determined in archival human liver tissues by immunohistochemistry.

RESULTS

While MAdCAM-1 was not detected in normal fetal or adult human liver, expression was observed in association with portal tract inflammation in a variety of liver diseases. Detailed analysis of liver biopsies from patients with hepatitis C showed a positive correlation between the portal/periportal component of the histological activity index (HAI) grade and the presence or absence of MAdCAM-1 expression.

CONCLUSION

MAdCAM-1 expression may be important in the recruitment of lymphocytes to the liver during inflammation.

Genomic instability is an early event during the progression pathway of ulcerative-colitis-related neoplasia

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon associated with a high risk of colorectal cancer. This increased cancer risk is thought to result from the cellular damage induced by the inflammatory field. The aim of this study was to determine the pattern and time course of genomic instability occurring in UC-related neoplasia. Sites of cancer, dysplasia, and nondysplasia from 14 UC colectomy cases containing cancer were analyzed for chromosomal alterations by comparative genomic hybridization (CGH) and for microsatellite instability using a series of 10 microsatellite markers. Clonal chromosomal alterations were present in 85% of cancer sites, 86% of dysplasia sites, and 36% of nondysplasia sites. Losses of chromosome 18 or 18q and chromosome 5 or 5q were common in cancer and dysplasia and were occasionally detected in nondysplasia. High-level microsatellite instability was detected in the cancer and dysplasia of two cases. Samples that demonstrated high-level microsatellite instability were unlikely to have chromosomal alterations demonstrable by CGH. These studies suggest that the predominant type of genomic instability in UC-related neoplasia is associated with chromosomal alterations and that this type of genomic instability frequently occurs before the development of histologically defined dysplasia.

GB virus C (GBV-C/HGV) and E2 antibodies in children preliver and postliver transplant

The association of GB virus type C (GBV-C) virus and clinical disease is uncertain. The role of GBV-C and (Envelope) E2 antibody in children with liver transplants has not been determined. This study's aim is to examine the prevalence of GBV-C in children with liver transplants, to assess the relationship of GBV-C to posttransplant hepatitis, and to determine the role of E2 antibodies. Sera from 34 children, preliver and postliver transplant, between 1989-1996 were tested for GBV-C (Ribonucleic acid) RNA by the automated Abbott LCx PCR assay. Anti-E2 antibodies were detected by an Abbott immunoassay. Recent posttransplant liver biopsies were examined for hepatitis. The results of the study determined that pretransplant, four children (12%) were GBV-C RNA positive. Posttransplant, 14 (42%) children were GBV-C RNA positive. The GBV-C RNA positive conversion rate was 33% (CI 17.2-55.7%). Patients received blood products from a mean of 68 +/- 34 donors, which correlated with GBV-C acquisition. There was no difference in the incidence (32%versus 36%; p = 0.726) or severity (grade 2.00 versus 0.68; p = 0.126) of posttransplant hepatitis in the liver biopsies of GBV-C RNA negative and/or positive children, respectively. Pretransplant, nine of 32 children were anti-E2 positive. Posttransplant, eight of 32 children were anti-E2 positive, including five children who were anti-E2 positive pretransplant. Of nine children who were anti-E2 positive and GBV-C RNA negative pretransplant, three became GBV-C RNA positive posttransplant. The results of this study conclude that the prevalence of GBV-C infection in children postliver transplantation is high and that blood product transfusions correlate with GBV-C acquisition. Also, no correlation was found between GBV-C RNA and the incidence or severity of posttransplant hepatitis. Finally, E2 antibody presence before transplantation failed to provide complete protection from GBV-C acquisition.

Disseminated intravascular meconium in a newborn with meconium peritonitis

A 3-day-old premature infant with meconium peritonitis, periventricular leukomalacia, and pulmonary hypertension died with respiratory insufficiency. An autopsy disclosed intravascular squamous cells in the lungs, brain, liver, pancreas, and kidneys. Numerous pulmonary capillaries and arterioles were occluded by squamous cells, accounting for pulmonary hypertension. Brain parenchyma surrounding occluded cerebral vessels showed infarct and gliosis. A mediastinal lymph node filled with squamous cells alluded to the mechanism by which these cells from the peritoneal cavity likely entered the bloodstream--namely, via diaphragmatic pores connecting with lymphatics. Thus, disseminated intravascular meconium rarely may complicate meconium peritonitis and have devastating consequences.

Angiomyolipoma of the liver in fine-needle aspiration biopsies: its distinction from hepatocellular carcinoma

BACKGROUND

Angiomyolipoma (AML) of the liver is an uncommon benign lesion that may be difficult to distinguish clinically, radiographically, and morphologically from hepatocellular carcinoma (HCC).

METHODS

Fine-needle aspiration biopsies (FNAB) of three AMLs of the liver were compared with FNABs from eight cases of HCC. Immunoperoxidase stains for HMB-45, muscle specific actin, and CAM 5.2 were performed on two cell blocks and one resection of AML.

RESULTS

All three AMLs yielded cellular aspirates. They were composed of clusters of cells with arborizing transgressing endothelium but no peripherally wrapping endothelium. Smooth muscle cells of AML showed fibrillar cytoplasm and indistinct cytoplasmic borders; HCC showed granular cytoplasm and distinct cytoplasmic borders. Extramedullary hematopoiesis was present only in AML. Mitotic figures were seen only in HCC. Intranuclear inclusions, nucleoli, and large, atypical cells were present in both AML and HCC. Fat was seen in only one case of AML and was scant. Immunoperoxidase stains for HMB-45 and smooth muscle actin were positive in AML and negative in adjacent normal liver. CAM 5.2 stain was negative in AML.

CONCLUSIONS

The cytologic features seen on FNABs of AML are distinct from those of HCC. Immunoperoxidase stains can aid in the definitive diagnosis on FNAB. It is important to recognize AML on FNAB to allow conservative clinical management.

Hepatic angiomyolipoma: a clinicopathologic study of 30 cases and delineation of unusual morphologic variants

Hepatic angiomyolipoma (AML) is frequently misdiagnosed. HMB-45 is a promising immunomarker for this tumor that leads to recognition of some AMLs with unusual morphology. The purpose of this collaborative study is to better define the morphologic variations of AML. Thirty AMLs were examined, including four biopsy specimens and two fine-needle aspirates. The diagnosis was confirmed by the presence of HMB-45-positive myoid cells. Almost half the cases were originally misdiagnosed as carcinomas or sarcomas. There was marked female predominance (25:5), and the mean age was 48.7 years (range 29-68). Three patients (10%) had evidence of tuberous sclerosis and all had renal AML. According to the line of differentiation and predominance of tissue components, the tumors was subcategorized into mixed, lipomatous (> or = 70% fat), myomatous (< or = 10% fat), and angiomatous type. The mixed type was the most common (11 resected cases), comprising sheets of epithelioid muscle cells admixed with islands of adipocytes, abnormal vessels, and frequently, hematopoietic cells. Six tumors (including three from biopsy specimens) were heavily fatty and showed predominantly adipocytes with epithelioid and short spindle myoid cells webbed between fat cells. Of 10 myomatous AMLs, five tumors showed a pure sinusoidal trabecular pattern and comprised mainly epithelioid cells. Typically, mature adipocytes were absent or scanty, but fat was seen as fine droplets within cytoplasm or as occasional large globules in sinusoids. Pelioid and inflammatory pseudotumor-like patterns were identified focally. Regarding cellular features of the myoid cells, most of the epithelioid cells were either eosinophilic or clear with spiderweb cell morphology. Three AMLs showed an almost purely oncocytic appearance with scanty fat. Large pleomorphic epithelioid cells existed as small foci. Spindle cells arranged in long fascicles were uncommon. D-PAS-positive globules were common around pelioid areas. Brown pigments with staining characteristics of hemosiderin and/or melanin were noted. In conclusion, we propose HMB-45-positive myoid cells as the defining criterion of hepatic AML, which is a tumor capable of dual myomatous and lipomatous differentiation and melanogenesis. Because of its protean morphologic appearance, recognition of the various variant patterns and cell types is important for a correct diagnosis, assisted by immunohistochemical confirmation with HMB-45. Trabecular and oncocytic cell tumors appear to stand out as distinctive subtypes.

Hepatitis after liver transplantation: the role of the known and unknown viruses

This study was designed to determine the cause of posttransplantation hepatitis in patients undergoing transplantation for liver disease of nonviral cause; the role of acquired hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis G virus (HGV) in posttransplantation hepatitis; and the course of posttransplantation hepatitis of unknown cause. Two hundred forty-three patients underwent transplantation for nonviral liver diseases (mean age, 48 years; 103 men, 140 women). Serological and virological assays for HBV and HCV were performed pretransplantation to exclude preexisting infection and posttransplantation to investigate the cause of posttransplantation hepatitis. Histology was graded on all available biopsy specimens; posttransplantation hepatitis was assessable in 150 patients. Posttransplantation hepatitis was present in 29% (44 of 150) of the patients after a median follow-up of 47 months (range, 1 to 101 months). Actuarial survival was significantly lower in patients with posttransplantation hepatitis compared with patients without (71% v 89% at 5-year follow-up; P = .03). HCV and HBV were identified posttransplantation in 14% and 9% of patients with hepatitis, respectively. After the exclusion of HCV and HBV infection, 22% (33 of 150) of the patients had posttransplantation hepatitis of unknown cause. HGV was present in 58% of these patients, but HGV was equally prevalent in patients without posttransplantation hepatitis. When patients with HBV and HCV were excluded, there was no difference in survival between patients with posttransplantation hepatitis compared with patients without (P = .08, log-rank test). Posttransplantation hepatitis was present in approximately 30% of the patients undergoing transplantation for nonviral diseases, with a median follow-up of 47 months. Known hepatitis viruses (HBV, HCV) were present in one fourth of the patients with posttransplantation hepatitis; 22% (33 of 150) of the patients had hepatitis of unknown cause, suggesting that other, as yet undiscovered, hepatitis viruses may exist.

Interpretation of biopsy findings in the transplant liver

With several thousand liver transplants being performed each year and many patients being managed in their local medical centers, much of the interpretation of transplant liver biopsy specimens has moved from the transplant hospital to the community setting. This article discusses both typical and more peculiar changes that occur in the transplant liver biopsy specimen. Accurate interpretation requires clear knowledge of these possible changes as well as knowledge of clinical data, such as time elapsed since transplantation and the patient's primary disease.

Cholestatic hepatitis C in liver allografts

Some liver allograft recipients with hepatitis C virus (HCV) infection develop hyperbilirubinemia, which might be the result of a cholestatic variant of hepatitis C. We evaluated all liver biopsy samples from 6 liver transplant recipients who had polymerase chain reaction-positive HCV infection and histologic evidence of hepatitis and jaundice and compared them with liver biopsy samples from a control group of transplant recipients with HCV hepatitis without jaundice. Patients with known ductopenic rejection, biliary obstruction, or co-infection with hepatitis A or B were excluded from the study. Measurement of viral titers and genomic typing were performed when possible. Six patients developed hepatitis and jaundice, with maximum bilirubin levels ranging from 5.8 to 47.6 mg/dL. In this group, 5 (83%) had moderate interface hepatitis (control group, 15%), 6 (100%) had confluent necrosis (control group, 12%), 5 (83%) had bridging fibrosis (control group, 18%), 4 (67%) had significant hepatocyte swelling (control group, 9%), 4 (67%) had prominent ductular proliferation (control group, 3%), and 6 (100%) had mild duct damage and inflammation (control group, 53%). All 6 of the patients with cholestasis had allograft failure. Of these, three allografts were available for review, which did not reveal occult obstruction, rejection, or duct loss. All patients in the control group have retained their allografts. In 4 patients with cholestasis, the median HCV RNA titer was 93.97 mEq/mL, with a mean of 54.19 mEq/mL (control mean = 5.2 mEq/mL). Five patients also underwent viral genomic typing: 2 with type 1a, 2 with type 1b, and 1 with mixed type 1a and 1b. Cholestasis in patients with posttransplantation hepatitis C may be caused by an aggressive HCV infection that exhibits histologic features of confluent necrosis, hepatocyte swelling, and/or ductular proliferation. Viral titers are often increased in such patients.

Fine needle aspiration biopsy of the liver: diagnostic problems

FNAB of the liver is a diagnostic test that can be used to identify the vast majority of neoplasms of a primary or metastatic nature. Well-prepared FNAB samples, in conjunction with cell button preparations, and correlation with the clinical history are necessary for optimal results. Even with the best of samples, however, well-differentiated hepatocellular neoplasms, both benign and malignant, and rare lesions still can remain difficult to diagnose by FNAB.

Pediatric liver tumors

The information in this chapter is a resource for the pathologist faced with a pediatric liver tumor. Each tumor is characterized concisely and appropriate references are provided for more detailed study. Examples of tumors are presented from the files of Children's Hospital-Oakland and from the University of California Medical Center.

The application of image analysis and neural network technology to the study of large-cell liver-cell dysplasia and hepatocellular carcinoma

Liver cell dysplasia (LCD) is considered a preneoplastic lesion, whose characterization and differentiation from hepatocellular carcinoma (HCC) and from the reactive changes seen in cirrhosis has been controversial. We studied 12 cases of LCD (large cell type) with image analysis techniques (IA) and compared the findings with those of HCC (n = 40), and a spectrum of non-neoplastic hepatic lesions including normal liver and cirrhosis (n = 49). A minimum of 200 Feulgen-stained nuclei were measured from each lesion with the CAS 200 image analysis system. The data were collected with the aid of CellSheet software. Thirty-four variables were measured, including geometric, textural, and photometric nuclear features and DNA ploidy. The data were analyzed with multivariate statistics and a backpropagation neural network (NN). Stepwise statistical analysis selected 22 variables that were statistically significant in the three groups with P values <.05. Various NN architectures were developed using these variables. The best NN architecture included a sigmoidal transfer function, 14 input, 16 hidden, and 3 output neurons. It trained to completion after 8,887 runs using 90% of the lesions. This NN yielded a 100% cross-validation rate for unknown cases. These data support the concept of LCD (large cell type) as a lesion that can be objectively distinguished from HCC and non-neoplastic liver. Our study also demonstrates the potential usefulness of IA for the evaluation of difficult histopathological problems.

Chromosomal alterations in ulcerative colitis-related neoplastic progression

BACKGROUND & AIMS

It is unclear whether genomic derangement precedes the histological development of dysplasia in ulcerative colitis (UC)-related neoplastic progression. The primary aim of this study was to determine if chromosomal alterations occur early in the progression pathway of UC-related neoplasia.

METHODS

Fluorescence in situ hybridization (FISH) was performed on nuclei dissociated from sites of cancer, dysplasia, and UC-involved nondysplastic epithelium in five UC-related cancer colectomy specimens using a panel of pericentromeric probes. Comparative genomic hybridization (CGH) was used to detect clonal chromosomal losses and gains in DNA extracted from these sites.

RESULTS

FISH analysis revealed significant and often dramatic alterations in chromosome copy number compared with controls in all biopsy specimens of cancer, dysplasia, and nondysplastic UC-involved epithelium. Clonal chromosomal losses and gains were detected by CGH in all but one analyzed site of dysplasia and cancer and in two of the five nondysplastic sites. FISH and CGH frequently detected the relative loss of chromosome 18.

CONCLUSIONS

Chromosomal alterations may occur early in UC-related neoplastic progression and seem to precede the histological development of dysplasia. Relative loss of 18q may be important in the progression of UC-related neoplasia. The detection of chromosomal alterations as an intermediate end point may prove useful in identifying patients at high risk for the development of colorectal cancer.

Diffuse intrahepatic biliary strictures in sarcoidosis resembling sclerosing cholangitis. Case report and review of the literature

We report a case of sarcoidosis with severe cholestasis and cholangiographic features of sclerosing cholangitis that responded dramatically to corticosteroid therapy. Although an association between sarcoidosis and primary sclerosing cholangitis has been suggested by previous reports, features suggestive of primary sclerosing cholangitis, including inflammatory bowel disease, hepatic histology and serum neutrophil cytoplasmic antibodies, were absent in this case. Cholangiography may be useful in the evaluation of patients with cholestatic sarcoid liver disease, and intrahepatic biliary strictures should be included in the spectrum of hepatic involvement by sarcoidosis. A trial of corticosteroid therapy may be of benefit in patients with bile ductal involvement by sarcoidosis.

Hepatitis G virus in patients with cryptogenic liver disease undergoing liver transplantation

To examine the prevalence of hepatitis G virus (HGV) in end-stage liver disease of unknown cause and the role of HGV infection in posttransplantation hepatitis, we studied 46 patients undergoing liver transplantation (mean age, 50 years; M:F, 18:28) with cryptogenic cirrhosis. HGV RNA was detected by polymerase chain reaction (PCR) and was quantified by a branched DNA (bDNA) assay. The prevalence of HGV RNA was determined in samples collected before and after liver transplantation and was found to be 22% and 67%, respectively. We evaluated the prevalence of posttransplantation hepatitis in 25 patients, 16 of whom were HGV-positive and 9 were HGV-negative. The proportion of patients with hepatitis was not significantly different in the two groups (38% in HGV-positive and 22% in HGV-negative patients). The median histological scores were significantly higher in liver biopsies from patients with HGV infection than in those without HGV infection (2 [range, 0-14] and 1 [range, 0-3]; P = .01), but the histological scores were low overall. The duration of follow-up was similar in the two groups. HGV RNA levels were not correlated with the severity of liver disease based on histological score (r = -.08). Graft survival and patient survival were not significantly different. We concluded that liver disease was frequent (32%) after transplantation in patients with a pretransplantation diagnosis of cryptogenic cirrhosis, although the disease was generally mild. Although HGV RNA was demonstrable in the majority (67%) of patients after transplantation, there was no relationship between the presence of HGV RNA and the presence of posttransplantation liver disease. The finding of posttransplantation hepatitis in the absence of known viruses (A-G), suggests that other, as-yet-unidentified viruses may be important.

Immunohistochemical evidence of disease recurrence after liver transplantation for primary biliary cirrhosis

Whether primary biliary cirrhosis (PBC) recurs after liver transplantation has remained an interesting and controversial issue; rejection, viral hepatitis, and drug effects all may mimic recurrent PBC histologically and biochemically. Furthermore, reliable clinical criteria for PBC recurrence are lacking. In this study, the issue of disease recurrence using a well-characterized monoclonal antibody (MAb), C355.1, that reacts with the immunodominant mitochondrial autoantigen of PBC (pyruvate dehydrogenase complex [PDC-E2]) was addressed. When used in an immunohistochemical assay, C355.1 produces intense apical staining of bile duct epithelium specifically in liver sections of patients with PBC and may be the earliest known marker of PBC. Immunohistochemical and histological analysis of serial liver biopsy specimens of 67 patients pre- and post-orthotopic liver transplantation (OLT), including 38 patients with PBC and 29 non-PBC liver disease controls, was performed. Sections were stained with MAb C355.1 or the control MAb C315 and analyzed to determine whether there was a recurrence of apical reactivity in the bile ducts of the posttransplantation biopsy specimens. The immunohistochemical staining was correlated with the histological findings and serum biochemistries at the time of the biopsy. Our data indicate that a significant number of patients who underwent transplantation for PBC (28 of 38) but not controls (0 of 29) develop a staining pattern of liver bile duct epithelium with MAb C355.1 that is indistinguishable from the pretransplantation pattern. Of the 28 patients with this apical staining pattern, 8 were characterized histologically as possible recurrent PBC, 2 as chronic rejection, 2 as acute rejection, 9 as nonspecific changes, 4 as normal or near normal, and 3 had other histological changes. Only 50% of the patients with apical C355.1 staining had liver enzyme levels suggestive of cholestasis. Thus, there appears to be immunohistochemical evidence that supports the concept of recurrence of PBC after OLT. The appearance of biliary epithelial abnormalities before the clinical appearance of disease is important not only for liver transplantation but also for understanding the natural history of PBC.

Functional analysis of grafts from living donors. Implications for the treatment of older recipients

OBJECTIVE

Living-related liver transplantation (LRLT) has established efficacy in children. In a larger recipient, LRLT requires the use of a small graft because of limits on the donor hepatectomy.

SUMMARY BACKGROUND DATA

The minimum graft weight required for successful transplantation has not been well established, although a characteristic pattern of graft dysfunction has been observed in our patients who receive small grafts. The authors present a clinicopathologic study of small liver grafts obtained from living donors.

METHODS

Clinical and histologic data were reviewed for 25 patients receiving LRLT. In five older recipients (small group), the graft represented 50% or less of expected liver weight, whereas in 20 others (large group), the graft represented at least 60% of expected liver weight. A retrospective analysis of graft function was conducted by analyzing clinical parameters and histology.

RESULTS

In the small group, 2 of 5 grafts (40%) were lost due to poor function, leading to one patient death (20% mortality), whereas in the large group, 2 of 20 grafts (10%) were lost due to arterial thrombosis without patient mortality. Early ischemic damage related to transplant was comparable with aspartate aminotransferase 203 +/- 23 (small group) and 290 +/- 120 (large group) at 24 hours (p = not significant). Early function was significantly decreased in the small group, with prothrombin time 18.2 +/- 2.2 seconds versus 14.8 +/- 1.6 seconds (large group) on day 3 (p = 0.034). All small group patients developed cholestasis with significantly increased total bilirubin levels at day 7 (16 +/- 5.2 mg% vs. 3.7 +/- 2.7 mg%; p = 0.021) and day 14 (12.0 +/- 7.4 vs. 1.8 +/- 0.7; p = 0.021) compared with the large group. Protocol biopsies in the small group revealed a diffuse ischemic pattern with cellular ballooning on day 7, which progressed to cholestasis in subsequent biopsies. Large group biopsies showed minimal ischemic changes. Three small group patients recovered with normal liver function by 12 weeks.

CONCLUSIONS

Clinical recovery after a small-for-size transplant is characterized by significant functional impairment associated with paradoxical histologic changes typical of ischemia. These changes apparently are due to graft injury, which can only be the result of small graft size. These findings have significant implications for the extension of LRLT to adults.

Failure patterns of cryopreserved vein grafts in liver transplantation

Reports of early success with cryopreserved saphenous veins (CSV) as arterial conduits led us to develop cryopreserved iliac veins (CIV) as interposition grafts for portal vein reconstruction in living-related liver transplantation (LRLT). Despite encouraging short-term results, retrospective analysis of long-term cryopreserved vein graft performance in LRLT at our institution has revealed a high rate of late graft failures. Between July 1992 and JUly 1994, interposition grafts (CIV for portal vein interposition n=4, CSV for portal vein interposition n=3, and CSV for hepatic artery interposition n=2) were utilized in 7 LRLT. (Two transplanted organs had both CIV and CSV grafts.) Recipients included 5 children and two small adults (median: 3.5 years, range: 0.5--59 years). Posttransplant follow-up in excess of 36 months revealed portal vein (PV) and hepatic artery (HA) complications of cryopreserved grafts in each patient. PV complications included aneurysm (n=4) diagnosed at 28, 24, 18, and 1.5 mo, stricture (n=1) diagnosed at 11 mo, and thrombosis (n=1) diagnosed at 18 mo posttransplantation. All portal vein complications have been managed without retransplantation, but one (PV thrombosis) necessitated surgical shunt therapy. Each CSV hepatic artery interposition graft has been complicated by thrombosis (diagnosed at 11 days and 24 mo posttransplant) necessitating retransplantation. Based on these observations, we have adopted alternative strategies for HA and PV reconstruction. At present, 11 LRLT have been performed without cryopreserved vein conduits over 17 mo with no vascular complications. While this study does not permit statistical analysis, these results discourage the use cryopreserved iliac veins for portal interposition and cryopreserved saphenous veins for arterial interposition in liver transplantation.

Vanishing bile duct syndrome temporally associated with ibuprofen use

Nonsteroidal anti-inflammatory drugs are widely used, but the potential hepatotoxic side effects are not always appreciated. Herein, we report the first case, to our knowledge, of an atopic patient in whom severe cholestatic jaundice from bile ductopenia developed 3 wk after initiation of ibuprofen therapy. This drug-induced vanishing bile duct syndrome is probably an immunological (hypersensitivity) reaction. Vanishing bile duct syndrome as a consequence of ibuprofen use should be considered as a potential cause of chronic cholestasis when other more common etiologies have been excluded.

Hepatitis B and C coinfections and persistent hepatitis B infections: clinical outcome and liver pathology after transplantation

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are common complications after orthotopic liver transplantation (OLT), but the liver pathology and clinical outcomes of HBV infection with HCV coinfection have not been thoroughly examined. In this study, we used the polymerase chain reaction (PCR) to detect HBV and HCV in pre- and post-OLT sera of 38 patients and correlated the findings with clinical outcome and liver pathology. Of 13 patients who were HBV and HCV negative before OLT, 9 acquired HBV infection, and 4 developed acquired HBV and HCV coinfections after OLT. Persistent HBV infections were present in 10 patients. Three patients with pre-OLT HBV infections developed persistent HBV and acquired HCV coinfections after OLT; 5 with pre-OLT HCV infections developed acquired HBV and persistent HCV coinfections after OLT, and 7 had persistent HBV and HCV coinfections before and after OLT. Portal/periportal inflammation was the same in all groups; however, lobular inflammation and fibrosis were more severe in patients with persistent HBV infections and in those with acquired HBV and HCV coinfections. Two major histopathological patterns were present in patients with HBV and HCV coinfections, one with predominant features of HCV infection, and the other with those of HBV infection. Patients with post-OLT HBV and HCV coinfections had survival rates similar to those with acquired HBV infection, whereas patients with persistent HBV infections experienced more allograft loss caused by chronic hepatitis or fibrosing cytolytic hepatitis, and had a more dire clinical outcome than the others. Although the limited numbers reported in this study prevent a definitive conclusion, our data suggest that in patients with HBV and HCV coinfections, the presence of HCV may improve the clinical outcome as compared with the expected outcome of persistent HBV infection alone.

Fibrosing cholestatic hepatitis in renal transplant recipients

Fibrosing cholestatic hepatitis in a specific histologic manifestation of hepatitis B virus infection consisting of periportal fibrosis, hepatocyte ballooning, cholestasis, a relatively scant inflammatory infiltrate, and marked overexpression of hepatitis B viral antigens in hepatocytes. Until recently, fibrosing cholestatic hepatitis had been reported only in recipients of liver allografts. In this report, we present two patient in whom this lesion developed following renal transplantation. Both patients had previous liver biopsies showing relatively mild histologic changes. In one patient, the lesion developed early after retransplantation, during the period of maximal immunosuppression. However, in the second patient this lesion developed after withdrawal of immunosuppression. In both cases, death occurred within a few months because of progressive liver disease. Since this lesion can develop in "relatively healthy" hepatitis B carriers following transplantation of organs other than liver, these patients should have careful monitoring of their liver disease. Moreover, since the disease may progress despite withdrawal of immunosuppression, these patients would clearly benefit from the development of more effective therapies for posttransplant hepatitis B.

Fine-needle aspiration biopsy of the liver: diagnostic problems

FNA of the liver is a diagnostic test that can be used to identify the vast majority of neoplasms of a primary or metastatic nature. Well-prepared FNA samples, in conjunction with cell button preparations, and correlation with the clinical history are necessary for optimal results. Even with the best of samples, however, well-differentiated hepatocellular neoplasms, both benign and malignant, and rare lesions still can remain difficult to diagnose by FNA.

Cryoglobulinemia presenting after liver transplantation

Essential mixed cryoglobulinemia is frequently associated with chronic hepatitis C. Three patients undergoing transplantation for end-stage chronic hepatitis C in whom cryoglobulinemia with vasculitis developed after transplantation are described. Hepatitis C virus (HCV) infection was confirmed in the 3 patients by the presence of HCV RNA detected by polymerase chain reaction. The time interval between transplantation and the first expression of vasculitis was 1, 5, and 17 months. Type II cryoglobulins were detected in the sera of all 3 patients. All patients developed cutaneous vasculitis, requiring digital amputation in 1 case. Two patients developed membranoproliferative glomerulonephritis. Plasmapheresis and the addition of cyclophosphamide led to an improvement in the renal disease in 1 case, whereas no treatment was able to reverse the renal failure in the other case. One patient developed an autoimmune hemolytic anemia 4 years after transplantation. One patient died of multiorgan failure 5 months after transplantation. We propose that HCV-associated cryoglobulinemia could become clinically significant only after orthotopic liver transplantation, possibly due in part to posttransplant increase in viremia as reflected by HCV RNA levels. These results confirm previous observations suggesting that HCV infection is important etiologically in the pathogenesis of cryoglobulinemia.

Hepatic granulomas following liver transplantation. Clinicopathologic features in 42 patients

Liver granulomas have long been known to pose diagnostic problems for pathologists; however, their prevalence and associated etiologic factors have not been studied in liver transplant patients. We reviewed 3632 liver biopsy specimens from 563 patients at two institutions and identified 42 patients with posttransplant granulomas. A possible or probable etiologic factor was identified in 30 (71%) cases. Most were epithelioid granulomas and microgranulomas located in the parenchyma associated with hepatocyte necrosis (21 cases, 50%). Portal-based granulomas were associated with recurrent primary biliary cirrhosis (5 cases, 12%), acute cellular rejection (2 cases, 4.8%), and a foreign body-type reaction (1 case, 2.4%). One case was associated with tuberculosis (2.4%), 4 cases occurred in a fatty liver (9.5%), and 8 patients had liver granulomas but no other significant abnormality. The granulomas were most frequent in the first 7 months after transplantation when the patients were biopsied more often and underwent episodes of rejection or acute hepatitis. Portal-based granulomas in this period were usually associated with acute cellular rejection. After 7 months, the frequency of granulomas as well as the number of biopsies decreased and portal-based granulomas associated with recurrent primary biliary cirrhosis were most common (5 cases, 12%). Rare, late-appearing parenchymal granulomas were also seen (3 cases) and consisted of 1 lipogranuloma and 2 cases of epithelioid granuloma. The latter were thought, in 1 patient, to be associated with parenchymal hepatocyte necrosis; the others were of unknown etiology.

Apolipoprotein B mRNA-editing protein induces hepatocellular carcinoma and dysplasia in transgenic animals

Apolipoprotein (apo-) B mRNA editing is the deamination of cytidine that creates a new termination codon and produces a truncated version of apo-B (apo-B48). The cytidine deaminase catalytic subunit [apo-B mRNA-editing enzyme catalytic polypeptide 1 (APOBEC-1)] of the multiprotein editing complex has been identified. We generated transgenic rabbits and mice expressing rabbit APOBEC-1 in their livers to determine whether hepatic expression would lower low density lipoprotein cholesterol concentrations. The apo-B mRNA from the livers of the transgenic mice and rabbit was extensively edited, and the transgenic animals had reduced concentrations of apo-B100 and low density lipoproteins compared with control animals. Unexpectedly, all of the transgenic mice and a transgenic rabbit had liver dysplasia, and many transgenic mice developed hepatocellular carcinomas. Many of the mouse livers were hyperplastic and filled with lipid. Other hepatic mRNAs with sequence motifs similar to apo-B mRNA were examined for this type of editing (i.e., cytidine deamination). One of these, tyrosine kinase, was edited in livers of transgenic mice but not of controls. This result demonstrates that other mRNAs can be edited by the overexpressed editing enzyme and suggests that aberrant editing of hepatic mRNAs involved in cell growth and regulation is the cause of the tumorigenesis. Finally, these findings compromise the potential use of APOBEC-1 for gene therapy to lower plasma levels of low density lipoproteins.

Influence of ductal pressure and infusates on activity and subcellular distribution of lysosomal enzymes in the rat pancreas

BACKGROUND & AIMS

Subcellular redistribution of lysosomal enzymes into the zymogen-enriched fraction (cosedimentation) in pancreatic homogenates occurs after different pancreatic injuries and has been proposed to be the trigger event for acute pancreatitis. This phenomenon is now studied in models of biliary pancreatitis.

METHODS

The bile-pancreatic duct in rats was either obstructed or retrogradely infused at different degrees of pressure and with solutions of various injurious potential. Controls were untreated or sham operated. Six hours later, the pancreas was analyzed for the total activity of cathepsin B and beta-galactosidase and their distribution among subcellular fractions.

RESULTS

In control animals, 17% and 29%, respectively, of these lysosomal enzymes were found in the zymogen fraction. Redistribution occurred after all duct manipulations, including obstruction. In contrast to sham operation and duct obstruction, all modes of duct infusion resulted in marked increases in the total activity of lysosomal enzymes.

CONCLUSIONS

Increased lysosomal activity in models of biliary pancreatitis might contribute to acinar injury or represent a cellular repair mechanism. Cosedimentation at a certain extent is a physiological event. Redistribution reflects a uniform response to a range of perturbations, some of which do not cause pancreatitis. Thus, it seems unlikely that redistribution is the trigger event for acute pancreatitis.

Energy metabolism in mouse pancreas in response to different dosages of a CCK analogue

Stimulation of the exocrine pancreas with cholecystokinin analogues leads to a variety of intraacinar processes, many coupled to energy consumption. It was hypothesized that extensive ATP depletion could play a role in the pathophysiology of acute pancreatitis, especially in the hyperstimulation (cerulein) model. Mice received seven intraperitoneal injections of cerulein at hourly intervals, at doses ranging from physiological (0.1 micrograms/kg) to pharmacological (50 micrograms/kg). A single dose of cerulein induced a 28-33% decrease in ATP, whereas a complete course of injections led to a nadir as low as 45% of the control value. The overall pattern of ATP tissue content during the observed time course was surprisingly similar in all four groups and statistically not different at any time point. Until 12 h, ATP levels in all groups remained below the control value. In contrast, serum amylase and light microscopy reflected a degree of pancreatitis in a close dose-response pattern to the administered cerulein dose. These findings suggest that ATP depletion--although probably facilitating acinar damage--does not seem to play a causal or primary role in the pathophysiology of acute pancreatitis.

Liver transplantation for hepatocellular carcinoma: results with preoperative chemoembolization

At the University of California, San Francisco, 17 patients who met the following criteria-hepatic tumor unresectable because of location or inadequate liver reserve, no metastases, HBsAg negative, no tumor larger than 5 cm in diameter, and no more than three tumors--were enrolled prospectively in a protocol employing preoperative chemoembolization to assess whether orthotopic liver transplantation (OLT) could cure a majority of highly selected patients with hepatocellular carcinoma (HCC). Thirteen patients had biopsy-proven HCC, 2 had the fibrolamellar variant, and 2 had radiological findings of HCC but no biopsy confirmation. Fourteen had underlying liver disease. All arteriographically apparent lesions were chemoembolized using a mixture including Gelfoam powder, doxorubicin, mitomycin-c, and cisplatin. Eight patients with poor hepatic reserve were chemoembolized when a donor organ became available, whereas 9 patients were chemoembolized and then placed on the waiting list. The only complication of chemoembolization was a gangrenous gallbladder in 1 patient. Thirteen patients underwent liver transplantation (2 patients without prior histological confirmation of carcinoma had no identifiable tumor at OLT); 3 patients developed metastases between the time of enrollment and donor organ availability and subsequently died; and 1 patient underwent a trisegmentectomy. Ten of the 11 patients with biopsy-proven HCC who underwent transplantation remain free of recurrent cancer at a median of 40 months; 1 patient died at 6 months of lymphoproliferative disease with no cancer found at autopsy. Although the role of chemoembolization is uncertain, these data show that the majority of carefully selected patients with HCC may achieve long-term survival with OLT.

Effect of hypergastrinemia and blockade of gastrin-receptors on pancreatic growth in the mouse

BACKGROUND/AIM

The present study evaluates whether endogenous gastrin regulates pancreatic growth in the mouse.

MATERIALS AND METHODS

Male NMRI mice weighing 12-15 g were assigned to six groups (10 mice/group) which were treated with different combinations of 0.9% NaCl, omeprazole, a CCK-A antagonist, a CCK-B antagonist, loxiglumide, and L365, 260 for 10 days each according to different protocols.

RESULTS

Omeprazole caused a marked, 10-fold increase in serum gastrin which was not affected by the gastrin antagonist, but markedly reduced by the CCK-A antagonist. The marked increase in endogenous gastrin caused by omeprazole did not promote pancreatic growth in any way. Similarly, the gastrin antagonist did not inhibit pancreatic growth. In contrast, the CCK-A antagonist significantly decreased pancreatic weight and protein content.

CONCLUSIONS

The present results strongly suggest that endogenous gastrin--in contrast to CCK--does not regulate pancreatic growth in the mouse. The inhibitory effect of loxiglumide on omeprazole-induced increase in serum gastrin might be explained by recent findings which showed that CCK-A antagonists can stimulate gastric acid secretion probably due to a reduction of the inhibitory effect of basal CCK on the D-cell and its somatostatin release. Probably such a slight stimulation of gastric acid secretion caused by the CCK-A antagonist might reduce the gastrin increase caused by omeprazole's abolishment of acid secretion.

Effects of C1-esterase inhibitor in three models of acute pancreatitis

The present studies were done to evaluate the therapeutic potential of C1-esterase inhibitor in three different models of acute pancreatitis: (1) Edematous pancreatitis with acinar cell necrosis was induced by 7-h ip injections of 50 micrograms/kg cerulein in mice; (2) Hemorrhagic pancreatitis was induced by feeding a choline-deficient, ethionine-supplemented (CDE) diet in mice; and (3) Hemorrhagic pancreatitis was induced by retrograde infusion of 0.6 mL 5% sodium-taurocholate into the pancreatic duct in rats. C1-esterase inhibitor was given at 100 mg/kg iv before the onset of pancreatitis and at certain intervals thereafter. The severity of pancreatitis was assessed at various times after its onset by determination of serum amylase, by grading of histological alterations, and by determination of survival (survival determined only in models of hemorrhagic pancreatitis). In some of the models, C1-esterase inhibitor slightly ameliorated the degree of histological alterations; the increase in serum amylase was reduced by C1-esterase inhibitor only in CDE diet-induced pancreatitis. In all three models, C1-esterase inhibitor, however, failed to cause major beneficial effects and also failed to improve survival in taurocholate- and diet-induced pancreatitis. Additional studies in 12 patients with acute pancreatitis showed that C1-esterase inhibitor activity was markedly increased in serum of all patients during the first 9 d of the disease, suggesting that C1-esterase inhibitor behaves like an acute phase protein. Taken together the results from the animal and the human studies, C1-esterase inhibitor appears to only have a limited potential for treatment of acute pancreatitis.

Histopathological characteristics of explanted human prosthetic arterial grafts: implications for the prevention and management of graft infection

OBJECTIVE

to study the histopathological characteristics of prosthetic vascular graft infection.

DESIGN

prospective clinical study over 2 years.

SETTING

University Hospital.

MATERIALS

36 infected and 29 uninfected (control) chronically implanted vascular prostheses (half aortic) were removed and 352 sections prepared.

CHIEF OUTCOME MEASURES

light microscopy (multiple stains), scanning electron microscopy (SEM), and multiple culture techniques to identify characteristics of healing, infection, and microorganisms.

MAIN RESULTS

Acute inflammation (AI) (neurophils, granulocytes and necrosis) were seen in 75% of infected grafts, were most prominent in the perigraft tissue and rarely seen on the luminal surface. These were usually well localised, leaving the remainder of a graft well incorporated with no signs of infection. In 25% of clinically infected, culture-positive grafts there was no significant acute inflammation. Chronic inflammation (CI) (macrophages, lymphocytes, monocytes, giant cells) was seen in 70% of both control and infected grafts. In 50% of both groups a significant lymphocytic population was composed exclusively of T-lymphocytes suggesting a true host vs graft response. Unincorporated chronically implanted grafts (> 1 yr) were seen with equal frequency in the two groups although more diffusely unincorporated grafts were infected. Microorganisms were cultured from 23 infected grafts (64%) and were, at microscopy, mostly found outside the graft and nerves on the luminal side.

CONCLUSIONS

This data cast doubt on criteria commonly used to distinguish graft infections and host vs. graft reactions from normal graft healing. Acute and chronic inflammation are not predictive of infection.

Reliability and predictive value of the National Institute of Diabetes and Digestive and Kidney Diseases Liver Transplantation Database nomenclature and grading system for cellular rejection of liver allografts

Pathologists participating in the National Institute of Diabetes and Digestive and Kidney Diseases Liver Transplant Database (LTD) created a histopathological grading system for acute liver allograft rejection, and tested it first for inter- and intra-rater reliability among a group of five pathologists experienced in liver and transplantation pathology. Specimens from post-transplantation biopsies from 48 patients with rejection, hepatitis, or other diagnosis(es) were reviewed. There was moderate to good (kappa = 0.40 to 0.55) inter-rater and good (kappa = 0.55 to 0.58) intrarater agreement for the diagnosis and exact grading of mild, moderate, or severe acute rejection, which improved when a short clinical history was provided. Thus, the scheme was reproducible, and few of the disagreements among the pathologists would have affected treatment decisions. Secondly, the ability of the grading system to predict an unfavorable short- or long-term outcome from the initial histopathological diagnosis of cellular rejection was tested on groups of 168 and 133 patients, respectively, from the three LTD clinical centers, who were followed up for at least 6 months after the first onset of rejection. This analysis showed that a higher histopathological grade of acute rejection on first biopsy diagnosis was significantly associated (P < or = .006) with both an unfavorable short-term outcome, defined by failure of the episode to resolve within 21 days or the need for aggressive immunosuppressive treatment, and a long-term outcome defined by death or retransplantation from rejection within 6 months of onset. Lastly, an analysis was performed to determine whether subjective rejection grading by the pathologist or certain "objective" histopathological features identified by logistic regression modeling were more accurate in predicting an unfavorable outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Image analysis and diagnostic classification of hepatocellular carcinoma using neural networks and multivariate discriminant functions

BACKGROUND

Hepatocellular carcinoma (HCC) is often difficult to diagnose in cytologic material and small tissue biopsies since histomorphologic information is minimal or absent. The potential for misdiagnosis is greatest in attempting to discriminate well-differentiated HCC from dysplastic hepatocytes in cirrhosis. We investigated the feasibility of developing artificial intelligence classification methods based on nuclear image analysis data for use as adjuncts to the morphologic diagnosis of HCC.

EXPERIMENTAL DESIGN

Ninety hematoxylin-eosin stained histologic slides including 56 with well- to poorly differentiated HCC and 34 showing a morphologic continuum from normal to markedly dysplastic benign hepatocytes were assembled from four laboratories. A relatively inexpensive PC-based image analysis system was used to measure 35 nuclear morphometric and densitometric parameters of 100 nuclei in each specimen. The data were randomized into classification training and testing sets containing equal numbers of benign and HCC samples. Objective diagnostic classification criteria for HCC based on neural networks and multivariate discriminant functions (DFs) were developed for the most discriminatory subsets of morphometric, densitometric, and combined morphometric/densitometric variables as selected by stepwise discriminant analysis of training data.

RESULTS

Morphometric parameters provided the best results with the following testing data positive and negative predictive values (PV+ and PV-) for HCC classification: 86.2% PV+ and 81.3% PV- for a linear DF, 85.7% PV+ and 76.5% PV- for a quadratic DF and 100% PV+ and 85.0% PV- for a neural network.

CONCLUSIONS

Our results demonstrate that nuclear image analysis-based objective classification criteria for HCC can be developed using artificial intelligence methods and that histologic material prepared at different institutions can be reliably classified. Neural networks for HCC classification were superior to linear and quadratic DFs. Morphometric data yielded the best results compared with densitometric or combined morphometric/densitometric data.

The effect of L-buthionine-[S,R]-sulfoximine on the pancreas in mice. A model of weakening glutathione-based defense mechanisms

L-Buthionine-[S,R]-Sulfoximine (BSO) decreases glutathione levels in various organs by inhibition of gamma-glutamylcysteine synthetase. We have examined the levels of total glutathione and oxidized glutathione in the pancreas of mice, as well as serum amylase and pancreatic histology, after BSO administration in two different ways. The injection of a single dose of BSO (5 mmol/kg body wt) decreased total glutathione to 10% of the control value. A similar depletion was observed after 24 h of oral administration of a 10 mM BSO solution, without changes in the levels of oxidized glutathione. BSO-induced pancreatic glutathione depletion--even if maintained for up to 14 d--did not cause morphological alterations of the pancreas or hyperamylasemia. Thus pancreatic glutathione depletion in itself does not lead to pancreatitis, although during development of experimental acute pancreatitis, glutathione depletion has been described. BSO might be used in animal models to weaken the glutathione-based acinar defense mechanisms against oxidant stress or to alter other physiologic processes in which glutathione is involved.

Lipopeliosis. An immunohistochemical and clinicopathologic study of five cases

Lipopeliosis is an unusual liver lesion in which sinusoids become engorged by fat globules. It arises in newly transplanted donor livers that display varying degrees of fatty change. If, after transplantation, hepatocyte necrosis secondary to ischemic or preservation injury occurs, the fat escaping the hepatocytes becomes sequestered in the sinusoidal spaces. We previously described this lesion in a case report; we now describe four more cases to define better the incidence, immunohistochemical features, and clinical spectrum. Of 101 transplanted livers, the lesion was noted in five of 28 (18%), with both preservation injury and mild to moderate fatty change present 1 week following transplantation. Factor VIII-related antigen, collagen IV immunoperoxidase, and oil red O stains confirmed the engorgement of sinusoids by fat droplets, and a stain for CD68-positive cells identified a macrophage reaction around the fat droplets. The patient in our original report developed severe graft dysfunction with residual scarring of the centrilobular zone. Two of the four additional cases had no residual side effects from the lipopeliosis; however, two cases were associated with loss of graft. We conclude that lipopeliosis may be fairly common (5% of transplants). Its clinical outcome can vary greatly and most probably depends on the extent of hepatocellular necrosis.

Toxicity of compound A in rats. Effect of increasing duration of administration

BACKGROUND

An olefin called compound A (CF2 = C(CF3)OCH2F) results from the action of soda lime or Baralyme on sevoflurane. We have demonstrated that rats exposed to the olefin for 3 h died at or were injured by olefin concentrations lower than those previously reported to produce these effects. The present report examines the impact of duration of exposure to the olefin on such effects.

METHODS

Twenty-three groups of ten Wistar rats breathed 0, 12.5, 25, 50, 75, 100, 125, 150, 175, 200, 225, and 250 ppm of the olefin in oxygen for 6 or 12 h. Rats that survived were killed on day 1 or day 4 after breathing the olefin, and specimens of brain, kidney, lung, liver, and small intestine were obtained from all rats for examination by microscopy using hematoxylin and eosin stain and a stain (proliferating cell nuclear antigen) for cell growth (regeneration).

RESULTS

The lethal concentrations in 50% of rats equaled 203 +/- 4 ppm (mean +/- SE) for a 6-h exposure period and 127 +/- 9 ppm for a 12-h exposure period, and both values were less than the previously determined value of 331 +/- 7 ppm for a 3-h exposure period. Compared with results from control rats (those breathing oxygen for 6 h or 12 h), only renal and pulmonary injury were found. Pulmonary injury only occurred at near-lethal concentrations. Renal injury (defined as necrosis of the outer stripe of the outer medullary layer or corticomedullary junction necrosis) occurred at and above 25-50 ppm for 6-h and 12-h exposures, respectively, a result similar to that previously obtained with a 3-h exposure. Exposure to 25-50 ppm stimulated cell regeneration in a dose-related manner.

CONCLUSIONS

In rats, lethal concentrations of the olefin and concentrations producing severe renal injury are inversely related to the duration of exposure to the olefin, exceeding by two- to fourfold peak concentrations that can be obtained in clinical practice. The threshold concentrations for nephrotoxicity (i.e., minimal toxicity) equal concentrations that can be produced in clinical practice. However, even if these threshold effects in rats apply to humans, they probably would not alter renal function. Although dose-related, neither the lethal nor the toxic effects are simply a function of cumulative dose (concentration-time).

Toxicity of compound A in rats. Effect of a 3-hour administration

BACKGROUND

Soda lime converts sevoflurane to CF2 = C(CF3)OCH2F, an olefin called compound A, whose toxicity raises concerns regarding the safe administration of sevoflurane via rebreathing circuits. The present report extends the findings of a previous investigation by others of the toxicity of this olefin, and establishes concentration-response relationships for such toxicity.

METHODS

Eighteen groups of ten Wistar rats breathed 0, 25, 50, 100, 200, 300, 350, and 400 ppm of the olefin in oxygen for 3 h. The olefin concentrations were developed in a square-wave manner by injection of saturated vapor followed by a continuous delivery of dilute vapor. The lethal concentration in 50% (LC50) of animals was estimated by logistic regression. Rats were killed on day 1 or day 4 after breathing the olefin, and specimens of brain, kidney, lung, liver, and small intestine were obtained from all rats for examination using light microscopy.

RESULTS

The LC50 equaled 331 ppm (95% confidence limits +/- 13 ppm). No injury resulted to lung or small intestine in either the experimental or the control group (those breathing only oxygen for 3 h). Renal injury (necrosis of the outer strip of the outer medulla, defined in this report as corticomedullary tubular necrosis) occurred at 50 ppm and greater; hepatic injury at 350 ppm and greater; and cerebral injury only at 400 ppm.

CONCLUSIONS

The lethal concentration and the threshold for toxicity of the olefin are less than previously reported. The threshold for nephrotoxicity reaches the range of values for the olefin that have been attained in clinical practice. Further studies are required to determine whether these results in rats can be extrapolated to patients.

Proposal for standardized criteria for the diagnosis of benign, borderline, and malignant hepatocellular lesions arising in chronic advanced liver disease

Although current literature contains many cases of putative premalignant hepatocellular proliferations and small hepatocellular carcinomas, no consistent nomenclature and diagnostic criteria have been put forward to describe them. These nodules, which are being detected by radiographic techniques in cirrhotic livers and removed during transplantation procedures, represent a new and challenging histologic spectrum of liver pathology. In this study, a multinational panel of five liver pathologists reviewed 23 such nodules and were able to reach a consensus on the diagnostic criteria and to devise a standard nomenclature to describe the histologic lesions. We recommend that benign nodules showing little histologic difference from cirrhotic nodules be classified as regenerative or macroregenerative, and nodules with atypical features not diagnostic of carcinoma be classified as borderline. Such standardization should facilitate further study of the pathologic features and clinical behavior of these lesions.

Histopathologic study of stenotic and occluded transjugular intrahepatic portosystemic shunts

PURPOSE

A detailed histopathologic analysis of three stenotic and two occluded transjugular intrahepatic portosystemic shunts was performed to evaluate the nature and cause of each shunt abnormality.

PATIENTS AND METHODS

The study group consists of five patients who developed a shunt stenosis or occlusion and subsequently underwent liver transplantation or autopsy. Shunt specimens were examined grossly and microscopically.

RESULTS

The pseudointima was composed of granulation tissue, which was generally denser and more cellular near the luminal surface. Pseudointima was thicker in the parenchymal portion of the shunt than at the venous ends. A contiguous single layer of endothelial-like cells lined the majority of the luminal surface of each shunt. Scattered debris and clot covered 10%-15% of the luminal surfaces. Transected bile ducts were noted in three cases. Bile staining was detected around the transected ducts, and bile pigment was incorporated into the developing pseudointima.

CONCLUSIONS

Pseudointimal hyperplasia appears to be the causative lesion in these obstructions. An inflammatory reaction incited by bile extravasation may have contributed to pseudointimal proliferation in three cases.