The inhibitory effect of interleukin 1beta on rat hepatocyte DNA synthesis is mediated by nitric oxide

Interleukin 1beta (IL-1beta) and nitric oxide (NO) have potent growth-regulatory effects on different cell types. We found that epidermal growth factor-induced DNA synthesis in primary cultures of adult rat hepatocytes was inhibited by NO when it was provided by addition to the cultures of S-nitroso-N-acetyl-penicillamine (SNAP), an NO donor, as well as by addition of IL-1beta in a dose-dependent manner. IL-1beta also induced NO production and inducible NO synthase (iNOS) gene expression. The inhibition of DNA synthesis by IL-1beta was completely abrogated when NO production was inhibited by N-monomethyl-L-arginine (NMA), a competitive inhibitor of iNOS. IL-1beta-receptor antagonist (IL-1ra), which interferes with the interaction of IL-1beta with target cells, also abolished the inhibitory effects of IL-1beta on hepatocyte DNA synthesis as well as IL-1beta-induced iNOS gene expression. We also found that hepatocyte DNA synthesis inhibition by IL-1beta was completely antagonized by providing deoxynucleosides to bypass the block in ribonucleotide reductase, a rate-limiting step in DNA synthesis, thus implicating this enzyme in the mechanism of growth inhibition by IL-1beta. These experiments extended prior observations on the growth-inhibitory actions of IL-1beta on hepatocyte DNA synthesis, involving the IL-1beta receptor, NO production, and ribonucleotide reductase.

Cell growth inhibition by a novel vitamin K is associated with induction of protein tyrosine phosphorylation

We have shown that a synthetic vitamin K analog, 2-(2-mercaptoethanol)-3-methyl-1,4-naphthoquinone or compound 5 (Cpd 5), potently inhibits cell growth and suggested that the analog exerts its effects mainly via sulfhydryl arylation rather than redox cycling. Since protein-tyrosine phosphatases (PTPases), which have pivotal roles in many cellular functions, have a critical cysteine in their active site, we have proposed PTPases as likely targets for Cpd 5. To test this hypothesis, we examined the effects of Cpd 5 on protein tyrosine phosphorylation of cellular proteins and on the activity of PTPases. We found that Cpd 5 rapidly induced protein tyrosine phosphorylation in a human hepatocellular carcinoma cell line (Hep3B) at growth inhibitory doses, and the effect was blocked by thiols but not by non-thiol antioxidants or tyrosine kinase inhibitors. Cpd 5 inhibited PTPase activity, which was also significantly antagonized by reduced glutathione. Furthermore, the well studied PTPase inhibitor orthovanadate also induced protein tyrosine phosphorylation and growth inhibition in Hep3B cells. These results suggest that inhibition of cellular PTPases by sulfhydryl arylation and subsequent perturbation of protein tyrosine phosphorylation may be involved in the mechanisms of Cpd 5-induced cell growth inhibition.

Transforming growth factor alpha (TGFalpha) in hepatocellular carcinomas and adjacent hepatic parenchyma

We examined stage T1 to T4 hepatocellular carcinomas (HCC) to determine whether transforming growth factor alpha (TGFalpha) presence differed between early- and late-stage HCC and between tumors with low and high proliferative rates. Paraffin sections from 36 HCC were evaluated for TGFalpha and the proliferation markers Kiel 67 antigen (Ki67) or proliferating cell nuclear antigen (PCNA) by immunoperoxidase staining. In 12 cases, double staining for TGFalpha and Ki67 was also performed. Eighty-one percent of tumors and 94% of adjacent liver sections contained TGFalpha. A trend toward inverse correlation was seen between the percentage of TGFalpha-positive tumor cells and the proliferative rate as determined by Ki67 staining. No clear correlation of TGFalpha to either tumor stage or percentage of PCNA-positive cells was seen. This study confirms the presence of TGFalpha in the majority of early- and late-stage HCC. Positivity within tumor tissue is consistent with autocrine or paracrine stimulation. A trend toward inverse correlation between TGFalpha-producing cells and the number of cycling cells suggests that rapidly proliferating tumors may consume this growth factor at an accelerated rate. Alternatively, other hepatic mitogens may have more functional significance in these latter tumors. Finally, the presence of TGFalpha in peritumoral hepatocytes suggests these cells as potential sources of paracrine stimulation for HCC.

The prediction of risk of recurrence and time to recurrence of hepatocellular carcinoma after orthotopic liver transplantation: a pilot study

Orthotopic liver transplantation (OLTx) in the presence of hepatocellular carcinoma (HCC) has been complicated by high recurrence rates. The ability to determine the risk and timing of HCC recurrence on an individual basis would greatly aid in the candidate selection process resulting in a more efficient use of donated organs and allow the individualization and better evaluation of adjuvant chemotherapy. The 214 patients who underwent OLTx in the presence of HCC were analyzed. From the 178 patients who survived more than 150 days, 71 (40%) have suffered HCC recurrence. Based on five risk factors, that is, gender, tumor number, lobar tumor distribution, tumor size, grade of vascular invasion, artificial neural network models predicting the likelihood of HCC recurrence within 1, 2, and 3 consecutive years after transplantation were developed. Based on model predictions, those combinations of risk factors that should/should not lead to recurrence were generated, allowing stratification of patients into the following three groups: 1) patients who should not suffer HCC recurrence and who should not need adjuvant therapy, 2) patients who will suffer recurrence and for whom postoperative chemotherapy significantly prolonged survival (but did not prevent recurrence), and 3) patients who may or may not suffer HCC recurrence and whose recurrence may be prevented by adjuvant chemotherapy. The outcome of OLTx for patients with HCC can be prognosticated based on a number of clinical variables. If verified through multicenter trials, these models could be made available to transplantation programs performing OLTx in the presence of HCC.

Utilization of hepatocyte-specific antibody in the immunocytochemical evaluation of liver tumors

A monoclonal antibody highly specific for benign and malignant hepatocytes (HepPar 1) was evaluated as part of an antibody panel used to differentiate hepatocellular from nonhepatocellular neoplasms. Sixty-five liver tumors and two extrahepatic tumors from patients with documented liver tumors were studied. Twenty-two neoplasms were of hepatocellular origin, three were combined hepatocellular/cholangiocarcinomas, and the remainder were of nonhepatocellular origin. HepPar 1 alone had an 82% sensitivity and 90% specificity for the detection of hepatocellular neoplasms. The corresponding values for alpha-fetoprotein were 57% and 97%. Polyclonal antibody to carcinoembryonic antigen (canalicular pattern) had a sensitivity of 79% and specificity of 97% for these tumors. The use of antibody panels provided superior results when compared with individual antibodies. In summary, HepPar 1 monoclonal antibody is a useful reagent for the differential diagnosis of hepatocellular tumors. Its utility is enhanced when it is used as part of a diagnostic antibody panel.

Phase II study of Spherex (degradable starch microspheres) injected into the hepatic artery in conjunction with doxorubicin and cisplatin in the treatment of advanced-stage hepatocellular carcinoma: interim analysis

Patients with advanced-stage unresectable hepatocellular carcinoma (HCC) were treated with intrahepatic arterial doxorubicin 30 mg/m2 plus escalating doses of cisplatin up to 100 mg/m2 in conjunction with rapid bolus injection of Spherex (degradable starch microspheres; Kabi Pharmacia, Lund, Sweden) into the hepatic artery, until slowing or reversal of blood flow. Treatments were repeated every 4 to 6 weeks until progression, or were continued indefinitely if there was disease stability or response. Thirty-five evaluable patients have so far been accrued to the study. Objective tumor responses have occurred in 22 patients (63%), of whom 20 had partial responses and two had complete responses. Four of the patients had reversal of tumor-induced portal vein thrombus. Toxicities included death, one patient (and a death of uncertain cause in an additional patient); hepatitis, two patients; pancreatitis, one patient; dyspnea/hypotension, two patients; and hepatic artery nontransient thrombosis in four patients. Six patients have survived 2 years and an additional 10 patients have survived 1 year. The addition of Spherex to intrahepatic arterial chemotherapy for advanced-stage HCC appears to be relatively safe and is well tolerated even in patients with portal vein thrombosis, which represent the majority of patients with advanced-stage HCC.

Inhibition of spermidine synthase gene expression by transforming growth factor-beta 1 in hepatoma cells

We screened genes responsive to transforming growth factor-beta (TGF-beta 1) protein in a human hepatoma cell line (Hep3B) using a PCR-mediated differential display technique, in order to investigate the mechanisms involved in TGF-beta-induced growth suppression. We found a gene that was down-regulated by TGF-beta 1 to be completely identical in an approx. 620 bp segment to the gene for the enzyme spermidine synthase, which mediates the conversion of putrescine into spermidine. Both spermidine synthase mRNA expression and its enzyme activity were decreased after TGF-beta 1 treatment of Hep3B cells. The inhibition of spermidine synthase gene expression by TGF-beta 1 protein was also observed in other hepatoma cell lines. The expression of genes for other biosynthetic enzymes in polyamine metabolism (ornithine decarboxylase and S-adenosylmethionine decarboxylase) was also inhibited to the same extent as for spermidine synthase, while the gene expression of spermidine/spermine N1-acetyltransferase, a catabolic enzyme, was relatively resistant to TGF-beta 1. Spermine levels in Hep3B cells were decreased by TGF-beta 1 treatment, although the levels of spermidine and putrescine were unchanged, probably due to compensation by remaining spermidine/spermine N1-acetyltransferase activity. Exogenously added spermidine or spermine, but not putrescine, partially antagonized the growth-inhibitor effects of TGF-beta 1 on Hep3B cells. Our data suggest that down-regulation of gene expression of the enzymes involved in polyamine metabolism, including spermidine synthase, may be associated with the mechanism of TGF-beta-induced growth suppression.

Comitogenic effects of vasoactive intestinal polypeptide on rat hepatocytes

The primary mitogens such as epidermal growth factor and transforming growth factor-alpha are known to stimulate DNA synthesis in primary cultures of adult rat hepatocytes. Vasoactive intestinal polypeptide (VIP) was found to amplify DNA synthesis induced by the primary mitogens and thus acted as a comitogen. The comitogenic effect of VIP was specific for the culture medium, suggesting that minor components in the medium were required for hepatocytes to fully respond to VIP. Glutamic acid is probably one of these minor components, although other components present in the nutrient-rich medium were also necessary for the full comitogenic effect. Other comitogens such as insulin, vasopressin, and angiotensin II interacted additively with low concentrations of VIP. The comitogenic effect of VIP was also found in hepatocytes cultured from regenerating rat liver after a partial hepatectomy. In the regenerating hepatocyte cultures, VIP can act as a mitogen even in the absence of the primary mitogen EGF. VIP mRNA was found in several organs including brain, intestine, and liver, and its expression was slightly induced in liver 24 h after a partial hepatectomy. These results suggest that VIP can act as a hepatic comitogen and may play a role in liver cell proliferation.

Fine needle aspiration diagnosis of hepatocellular carcinoma in metastatic sites

OBJECTIVE

To describe the fine needle aspiration (FNA) findings in metastatic hepatocellular carcinoma (HCC).

STUDY DESIGN

The cytologic findings in 15 cases of extrahepatic metastatic HCC diagnosed by FNA biopsy were reviewed.

RESULTS

The anatomic sites of the FNAs were: musculoskeletal (four biopsies from 3 patients), adrenal (4 patients), regional lymph nodes (4 patients), pancreas (2 patients) and pelvic region (1 patient). The 15 aspirates came from 14 patients, 11 of whom had a biopsy-proven primary HCC. In two of the remaining patients, the FNA diagnosis of HCC in the metastatic site was the initial diagnosis. In one of these patients the diagnosis was strongly suspected on clinical grounds, but in the other case it was unsuspected. In the remaining patient the liver mass and massive retroperitoneal adenopathy were biopsied concurrently. A trabecular pattern was observed in the smears and/or cell block preparations in nine cases. Eleven cases were well to moderately differentiated. Three cases were of large cell pleomorphic type. The remaining case was poorly differentiated.

CONCLUSION

Familiarity with the FNA cytology of HCC should allow its diagnosis in metastatic sites in most instances, even without a history of primary liver cancer.

Recurrent hepatocellular carcinoma after liver transplantation: spectrum of CT findings and recurrence patterns

PURPOSE

To correlate computed tomographic (CT) and serum tumor marker (alpha-fetoprotein [AFP] and des-gamma-carboxy-prothrombin [DGCP]) findings in recurrent hepatocellular carcinoma (HCC) after orthotopic liver transplantation (OLT).

MATERIALS AND METHODS

At retrospective review of the cases in 124 patients, CT findings were recorded by consensus of at least two nonblinded observers and compared with levels of AFP and DGCP.

RESULTS

In 35 patients (68 sites), CT depicted recurrent HCC (most frequently in lungs [n = 18] and liver allograft [n = 16]) in a single site in 19 patients (54%) and in more than one site in 16 patients (46%). No stage I or II HCC recurred after 18-78 months (mean recurrence, 39 months). Stage IVA HCC recurred four times as often as stage III HCC (P < .001). Abnormally high serum AFP and DGCP levels indicated 69% and 43%, respectively, in patients with recurrent disease.

CONCLUSION

HCC recurrence after OLT correlates with initial stage, and CT is more sensitive than serum tumor markers in its detection.

Growth control and gene expression in a new hepatocellular carcinoma cell line, Hep40: inhibitory actions of vitamin K

The growth characteristics of a newly established cell line, Hep40, derived from a human hepatoma are described. An absolute requirement was found for serum to mediate cell growth. Neither EGF, TGF-alpha, nor HGF altered cell growth in the presence or absence of serum. A partial suppression of cell growth was achieved by several TGF-beta family proteins. Affinity crosslinking gels using 125I-labeled TGF-beta showed a significant decrease in the TGF-beta cell-surface type II receptor in Hep40 cells, compared to the TGF-beta-sensitive Hep3B cell line. However, growth could be completely suppressed by addition of vitamins K to the culture medium in both Hep40 and several other hepatoma cell lines. Growth suppression by vitamins K was accompanied by an increased level of transcripts for c-myc, c-jun, and prothrombin genes, in contrast to the actions of TGF-beta 1 protein, which caused a decrease in the level of c-myc transcripts. These data show that this new human hepatoma cell line has partial resistance to growth inhibition by TGF-beta with a unique TGF-beta receptor defect. However, growth was completely suppressed by vitamins K. The differing gene expression patterns in response to TGF-beta as compared to vitamin K suggest that these two growth inhibitors act through differing pathways.

Growth inhibition of hepatoma cells induced by vitamin K and its analogs

Congeners of vitamin K are known to inhibit cell growth, although the precise mechanisms of growth inhibition are not well understood. To investigate the mechanisms involved, we synthesized several vitamin K analogs and examined their growth inhibitory activities for a human hepatoma cell line (Hep3B). The analogs included 2-methyl-1,4-naphthoquinone and trimethyl-benzoquinone, with and without aliphatic side chains at position 3. The side chains were all-carbon, thioethers, or O-ethers. Growth inhibition was potent in the compounds with short chains. The presence of a sulfur (thioether) or oxygen atom (O-ether) at the site of attachment of the side chain to the ring potentiated the activity. Apoptotic cell death was induced by the potent growth inhibitory compounds at low concentrations (20-60 microM), whereas necrotic cell death followed treatment with the same compounds at high concentrations. Expression of c-myc, which is thought to be associated with apoptosis, was increased by most of the compounds tested. Both reduced glutathione and cysteine almost completely abrogated the growth inhibitory effects of the thioether analogs as well as of vitamin K3. The effect of glutathione was less prominent for the all-carbon and O-ether analogs, and cysteine had no effect on these analogs. Catalase and deferoxamine mesylate had no significant effect on the thioether analogs, although they showed partial antagonistic effects on the growth inhibition of vitamin K3 and the all-carbon and O-ether analogs. Other non-thiol antioxidants tested had no effect on any of the analogs. Our results indicated that vitamin K-related quinoid compounds cause growth inhibition and both apoptotic and necrotic cell death and that the effects may be mediated by interaction at position 3 of their quinoid nuclei with cellular thiols.

Endothelin-1 expression by human hepatocellular carcinoma

Plasma levels of endothelin-1 (ET-1) are markedly higher in patients with hepatocellular carcinoma (HCC) than in normal controls. In order to further investigate this, we evaluated ET-1 immunoreactivity and mRNA expression in human HCC tissue. 70% (14/20) of the tumor tissues immunostained positively with ET-1 antibody and a significant association was observed between immunostaining in cells lining the tumor feeding vessels and tumor vascularity as determined by hepatic angiography. Moreover, the neoplastic hepatocytes in the tumors also stained positively with ET-1 antibody. All of the HCC tissue samples which immunostained for ET-1 also expressed ET-1 mRNA, indicating that ET-1 is actively synthesized by the tumors.

Integration of hepatitis B virus and alteration of the 1p36 region found in cancerous tissue of primary hepatocellular carcinoma with viral replication evidenced only in noncancerous, cirrhotic tissue

We have studied the genetic profile of the host genome and hepatitis B virus (HBV) in HBV-associated primary hepatocellular carcinoma (HCC). Comparative analyses of HCC cell line Hep 40 and the original biopsy specimens showed the episomal and replicating form of HBV only in the biopsy specimen from nontumor (NT) cirrhotic liver tissue, where a molecular change in the 1p36 region was detected (NT tissue showed a normal 46XY karyotype). In contrast, only integrated HBV was detected in HCC tumor (T) tissue and Hep 40 cells. Two HBV integration sites were identical in HCC tissue and the hyperdiploid Hep 40 cell line, where genetic alteration in the 1p36 region was identified. These data indicate that viral replication is ongoing only in NT cirrhotic-hyperplastic, chromosomally normal tissue with evidence for genetic instability. Only the tumor cell with altered genotype has virus integrated

Percutaneous ultrasound-guided needle biopsy of hepatic mass lesions using a cytohistologic approach. Comparison of two needle types

This study compared the ability to diagnose and accurately classify hepatic mass lesions by ultrasound-guided biopsy using two different needle types: a 20 gauge needle that yielded primarily cytologic material and an 18 gauge automated core biopsy needle. Slides prepared from each of the needle types were separately evaluated in a blinded fashion. The 20 gauge needle had a sensitivity of 90%, a specificity of 90%, and enabled exact tumor classification in 70% of cases. The 18 gauge core biopsy had a sensitivity of 85%, a specificity of 100%, and allowed exact tumor typing in 82% of cases. The sensitivity and specificity of both needle types combined was 98% and 100%, respectively, and all malignancies were correctly typed. A combined cytohistologic approach provides a highly accurate means of diagnosing and typing hepatic tumors and provides a suitable sample for confirmatory stains. Accurate tumor typing may affect therapeutic decisions.

The growth inhibitory effects of vitamins K and their actions on gene expression

A characteristic defect occurs in rat and human hepatocellular carcinoma (HCC) resulting in a loss of function of the vitamin K-dependent enzyme gamma-glutamyl-carboxylase in the tumor but not in the underlying liver. This causes the secretion of elevated levels of the immature or des-gamma-carboxylated form of prothrombin, which is used as a marker of HCC. We investigated whether, using the defined conditions of growing HCC cell lines in tissue culture, addition of the naturally occurring vitamins K1 or K2 or the synthetic vitamin K3 could influence the secretion of immature prothrombin. We found that vitamins K1, K2 and K3 all suppressed the secretion of immature prothrombin into the tissue culture medium. Vitamins K2 and K3 were also found to inhibit growth of the HCC cell line, in an apparently nontoxic and reversible manner. The influence of the vitamins K on the expression of some genes related to vitamin K action was examined and compared with that of another growth inhibitor, TGF beta 1 protein. The vitamins K were found to increase the expression of prothrombin and carboxylase messenger RNA and c-myc messenger RNA, but had no effects on the expression of TGF beta 1 messenger RNA. By contrast, TGF beta 1 increased TGF beta 1 messenger RNA levels, but had no effects on the other genes, suggesting a different pathway. The previously studied vitamin K3-mediated inhibition of growth was antagonized by the addition of catalase to the culture medium, but the inhibitory effects of vitamin K2 were not antagonized.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of a human hepatocellular carcinoma-associated tumor suppressor gene by differential display polymerase chain reaction

Differential gene expression between the normal human liver and a cell line derived from human hepatocellular carcinoma (HCC) was studied using the differential display polymerase chain reaction technique. One gene (mitochondria proteolipid like gene, MPL), whose expression was found to be repressed in the HCC cell line compared to normal liver, was cloned and sequenced. Amino acid sequence translated from the nucleotide sequence had a 73% homology with the carboxyl terminus of a mitochondria proteolipid (MPLP) isolated from beef heart. Northern blot analysis showed that the expression of the 3 kb MPL transcript was undetectable in 20 of 45 (44%) of human hepatocellular carcinomas, whereas only 1 of 14 (17%) of cirrhotic livers without HCC had undetectable expression when compared to normal livers. Hence MPL may be a candidate tumor suppressor gene for human HCC. This decrease in MPL expression was not due to gross alteration of its genomic DNA.

Differential display and cloning of messenger RNAs from the late phase of rat liver regeneration

Liver regeneration allows for recovery from hepatic injuries and regeneration after partial hepatectomy has been extensively used as a model system to study mitogenesis. Many genes have been identified that are induced in the early growing phase of liver regeneration but only a few genes have been identified that are induced in the later stages of regeneration before growth arrest. We used the newly discovered differential display method to identify several genes that were found to be induced at this later stage. Two of them were analyzed further. DNA sequencing of one of them revealed perfect homology to ribosomal protein S24. The sequence of the other gene did not have extensive homology to any sequence in the databases. These results may suggest a role of these two genes in the growth arrest phase of liver regeneration.

Percutaneous fine-needle aspiration of portal vein thrombi as a staging technique for hepatocellular carcinoma. Cytologic findings of 46 patients

BACKGROUND

Detection of portal vein tumor invasion in patients with hepatocellular carcinoma (HCC) is important in determining therapy and prognosis. Fine-needle aspiration (FNA) of a portal vein thrombus under ultrasound guidance facilitates the distinction of malignant from benign thrombus without resorting to laparotomy. In this study, the FNA findings of 46 patients who underwent this procedure are described.

METHODS

Cytologic findings of 48 aspirations from 46 patients who underwent percutaneous ultrasound-guided portal vein FNA were reviewed.

RESULTS

Twenty-nine of the 46 patients had a prior or concurrent biopsy-confirmed diagnosis of HCC at the time of portal vein FNA. On cytologic review, 39 of the aspirates were positive for malignancy, 6 were negative, and 3 were suspicious. Histologic follow-up of three of the six patients with negative aspirates confirmed bland thrombi in their portal veins. No complications resulted from the FNA procedure. Of the 39 aspirates positive for HCC, 22 were well differentiated, 5 were well to moderately differentiated, 9 were moderately differentiated, and 3 were poorly differentiated. In all except the poorly differentiated tumors, a trabecular cellular arrangement was detected in either smears or cell blocks. The cytologic findings in these aspirates, in general, mirror those found in aspirates of HCC in the liver proper.

CONCLUSIONS

Portal vein FNA is an effective, well tolerated method for disease staging of patients with HCC. When used as the initial diagnostic procedure, in selected patients, it can provide the diagnosis and staging information simultaneously.

Concomitant and isolated expression of TGF-alpha and EGF-R in human hepatoma cells supports the hypothesis of autocrine, paracrine, and endocrine growth of human hepatoma

Single and double immunohistochemical staining for transforming growth factor (TGF)-alpha and epidermal growth factor-receptor (EGF-R) was done in order to identify the localization of TGF-alpha and EGF-R in human hepatocellular carcinoma (HCC). Single immunohistochemical staining for TGF-alpha showed immunoreactivity in the cytoplasm of hepatoma cells in 22 of 30 cases of HCC. The localization of TGF-alpha was heterogeneous from HCC cells to HCC cells. In the surrounding regenerative nodules, the hepatocytes were mildly to moderately positive for TGF-alpha. The proliferating bile ductules and peripheral nerves were also immunopositive for TGF-alpha. Single immunohistochemical staining for EGF-R demonstrated a linear localization of EGF-R along the cell membrane of the HCC cells in 21 of the 30 cases of HCC. In the regenerative nodules, the hepatocytes also showed linear staining along the cell membrane. Double staining for TGF-alpha and EGF-R in 12 cases of HCC showed a concurrent localization of TGF-alpha and EGF-R in some hepatoma cells and isolated localization of the two substances of other HCC cells. These combinations either abruptly moved around or intermingled with each other. These immunohistochemical results thus support the theory of an autocrine, paracrine, and endocrine mechanism of TGF-alpha and EGF-R on the proliferation of human hepatocellular carcinoma.

Differentially expressed genes in TGF-beta 1 sensitive and resistant human hepatoma cells

The pathway of growth inhibitory cellular signal transduction by transforming growth factor beta 1 is largely unknown. Although several cellular proteins have been shown to be involved in the pathway, others remain to be identified. To search for other involved proteins, differentially expressed genes were examined in two human hepatoma cell lines that were respectively sensitive and resistant to growth inhibition by TGF-beta 1. Two such genes (SB31 and SB16) were characterized and found to be 100% homologous to leucine-rich alpha 2-glycoprotein and the ribosomal protein S25, respectively. SB31 was coordinately expressed with the TGF-beta I type II receptor, implicating a possible interaction. Expression of both genes in different cell lines can be broadly correlated with the sensitivity of the cell lines to growth inhibition by TGF-beta 1. SB16 expression is strongly suppressed in rat liver regeneration after partial hepatectomy, suggesting that it may have a role in liver growth.

Does advanced cirrhosis with portosystemic shunting affect the value of CT arterial portography in the evaluation of the liver?

OBJECTIVE

The purpose of this study was to determine the extent to which reduced portal blood flow in patients with advanced cirrhosis affects contrast enhancement of the liver during CT arterial portography (CTAP). We postulated that reduced and/or irregular hepatic enhancement would limit the efficacy of CTAP for the detection of hepatic tumors in these patients.

MATERIALS AND METHODS

We reviewed the records of 82 patients who had biopsy-proved advanced cirrhosis and who underwent CTAP. Three experienced radiologists evaluated the CTAP studies for adequacy of hepatic parenchymal enhancement. The presence or absence of varices also was documented in an attempt to select a subgroup of patients in whom CTAP showed better hepatic parenchymal enhancement.

RESULTS

Forty-seven (57%) of 82 patients had inadequate hepatic parenchymal enhancement to allow an evaluation of the entire liver. Inadequacy was attributable to areas of hyperdense parenchymal enhancement, areas of diffuse nontumoral mottling, or zones of poor parenchymal enhancement (soft-tissue attenuation equal to that of the paraspinal muscle). Parenchymal enhancement was inadequate in 62% of patients with varices and in 28% of patients without demonstrable varices.

CONCLUSION

Our results show that contrast enhancement of the liver during CTAP is altered significantly in patients with cirrhosis. Thus, it is likely that CTAP has limited usefulness for the detection or characterization of hepatic neoplasms in patients with cirrhosis.