摘要:

AbstractWe have found a hepatotrophic factor in plasma or sera of patients with fulminant hepatic failure and have purified human hepatocyte growth factor from plasma of these patients. In this study we developed an enzyme‐linked immunosorbent assay with high specificity and sensitivity for human hepatocyte growth factor in human serum. This assay for serum human hepatocyte growth factor is a sandwich method consisting of three steps. The standard curve for human hepatocyte growth factor appeared to be linear in the range of 0.20 to 12.50 ng purified human hepatocyte growth factor/ml (2.35 to 147 pmol/L). The assay took about 4 hr. Serum human hepatocyte growth factor values in patients with fulminant hepatic failure measured by enzyme‐linked immunosorbent assay showed a strong positive correlation with that by bioassay using rat hepatocytes in primary culture. The mean value of serum human hepatocyte growth factor for 30 normal subjects was 0.24 ± 0.12 (S.D.) ng/ml that for 23 patients with fulminant hepatic failure was 8.06 ± 1.76 (S.E.M.) ng/ml ‐>30 times greater than the mean value for normal subjects. Serum human hepatocyte growth factor levels in patients with acute hepatitis, chronic hepatitis and cirrhosis were found to be slightly higher than those in normal subjects, but only the increase in serum human hepatocyte growth factor of acute hepatitis patients was statistically significant. The enzyme‐linked immunosorbent assay for serum human hepatocyte growth factor should prove useful for serum human hepatocyte growth factor level measurement in patients with various liver diseases. (HEPATOLOGY 199

ISSN:0270-9139    

DOI:10.1002/hep.1840130102

出版商:W.B. Saunders    

年代:1991

数据来源: WILEY

摘要:

AbstractThe presence of heparin‐binding growth factors in liver was investigated by measuring the DNA synthesis stimulatory activity of liver extracts using quiescent fibroblasts as target cells. It was found that cytosolic fractions of mouse, rat and human liver, as well as isolated rat hepatocytes, contain a large amount of growth stimulatory activity. Most liver cytosolic activity is due to heparin‐binding growth factors, because>90% of the activity bound to a heparin affinity column in the presence of 0.8 mol/L NaCl, and was quantitatively eluted with 2 mol/L NaCl. Purification of these factors from both mouse and rat liver indicated the presence of both heparin‐binding growth factor‐1 and 2 in liver extracts. The level of the heparin‐binding growth factors, as estimated from the biological activity, is approximately 1 μg/gm mouse liver and 0.1 μg/gm rat and human liver. Heparin‐binding growth factor‐1–like factors were 10 times as abundant as heparin‐binding growth factor‐2–like factors. These data indicate that the cytosolic fractions of mouse, rat and human liver contain heparin‐binding growth factors as the primary growth factor for fibroblasts, and heparin binding growth factor‐1–like molecules account for most of the cytosolic activity in both mouse and rat liv

ISSN:0270-9139    

DOI:10.1002/hep.1840130103

出版商:W.B. Saunders    

年代:1991

数据来源: WILEY

摘要:

AbstractExperiments undertaken to investigate the binding of epidermal growth factor by hepatocyte nuclei showed that: (a) isolated nuclei from both normal and regenerating rat liver are capable of binding125I‐epidermal growth factor, (b) the nuclear epidermal growth factor‐binding protein is similar in molecular weight to the plasma membrane epidermal growth factor receptor, (c) monoclonal antibodies produced against the plasma membrane epidermal growth factor receptor recognize the nuclear epidermal growth factor receptor and (d) the nuclear receptor has an affinity for epidermal growth factor comparable to that of the plasma membrane receptor, but fewer (∼ 10%) nuclear receptors are available per protein unit compared with the plasma membrane. (HEPATOLOGY 1991;13:1

ISSN:0270-9139    

DOI:10.1002/hep.1840130104

出版商:W.B. Saunders    

年代:1991

数据来源: WILEY

摘要:

AbstractMultiple rounds of cell division were induced in primary cultures of rat hepatocytes in serum‐free medium containing 10 mmol/L nicotinamide and 10 ng epidermal growth factor/ml. Cells per culture almost doubled between day 1 and day 5. The proliferating cells were predominantly mononucleate. The time course of DNA synthesis in cultured hepatocytes showed that peaks of the incorporation of3Hthymidine were observed at 60 hr and 82 hr after plating. Labeling indices of the cells indicated that almost half the cells were labeled with3H‐thymidine in the periods 48 to 72 hr and 72 to 96 hr after plating. In addition, about 20% of the hepatocytes in culture initiated a second round of the cell cycle between 48 and 96 hr in culture, as demonstrated by the use of continuous treatments with3H‐thymidine and 5‐bromo‐2′‐deoxyuridine. Furthermore, by day 4 of culture, about 40% and 15% of metaphases resulted from a second and third round of cell division, respectively. The cultured hepatocytes on day 5 stained with albumin immunocytochemically, and the activity of tyrosine aminotransferase was induced by dexamethasone and glucagon on day 3. In addition, electron micrographs revealed that dividing cells not only had many characteristics of liver mitochondria and bile canaliculus‐like structures, but many also contained a few large peroxisomes with internal crystalline nucleoids. (HEPATOLOG

ISSN:0270-9139    

DOI:10.1002/hep.1840130105

出版商:W.B. Saunders    

年代:1991

数据来源: WILEY

摘要:

AbstractSomatic alterations of the c‐Ha‐rasgene were examined in 21 Japanese patients with hepatocellular carcinoma. Restriction endonuclease analysis by double digestion withMspI andHpaII revealed that DNAs from two of 21 hepatocellular carcinoma tissues were affected by nucleotide substitution at the twelfth amino acid coding sequence of the c‐Ha‐rasgene. DNAs from cirrhotic noncancerous liver tissue, but not leukocytes, of one of these patients possessed the mutation, whereas DNAs from noncirrhotic liver tissue and leukocytes of the other patient did not. In one of the nine patients harboring heterozygosity for c‐Ha‐ras—relatedBamHI‐fragments, the loss of one allele was demonstrated as a somatic change not only in DNA from the tumor tissue but also in DNA from the cirrhotic nontumorous tissue. In two of the 19 patients comparatively examined for digestion patterns of c‐Ha‐raslocus withHpaII andMspI, extensive methylation was observed as a somatic modification in both DNAs from the tumor and the cirrhotic nontumorous tissues. These results thus indicate that the genetic lesions affecting the c‐Ha‐rasgene do occur in human hepatocellular carcinoma and probably serve as one of the multiple steps in the process of hepatic carcinogenesis. (HE

ISSN:0270-9139    

DOI:10.1002/hep.1840130106

出版商:W.B. Saunders    

年代:1991

数据来源: WILEY

摘要:

AbstractThe expression of specific UDP‐glucuronosyltransferase isoforms in 2‐acetylaminofluorane—induced rat liver preneoplastic nodules was studied; livers from pair‐fed littermates were used as controls. For comparison, liver and kidney from 3‐methylcholanthrene—treated or untreated (control) rats were used. Steadystate UDP‐glucuronosyltransferase mRNA levels were determined by Northern blot analysis orin situhybridization of tissue sections using a 30‐mer oligonucleotide specific for the 3‐methylcholanthrene—inducible UDP‐glucuronosyltransferase (which is active toward 4‐nitrophenol) or a double‐stranded cDNA probe specific for androsterone—UDP‐glucuronosyltransferase. For 3‐methylcholanthrene—inducible UDP‐glucurono‐syltransferase, the mRNA level was very low in control liver; there was a 15‐fold increase after 3‐methylcholanthrene treatment. This mRNA was present at relatively high concentration in the kidney and there was a threefold increase after 3‐methylcholanthrene administration. In livers with preneoplastic nodules 1 mo after cessation of carcinogen administration, this mRNA concentration was approximately 15 times greater than in control liver. Similar changes in the level of the 3‐methylcholanthrene—inducible UDP‐glucuronosyltransferase were also observed byin situhybridization of tissue sections. Immunocytochemical studies using an antiserum that recognizes the 3‐methylcholanthrene–inducible UDP‐glucuronosyltransferase showed a marked increase in the concentration of this isoform in preneoplastic nodules compared with the adjacent nonnodular liver. Consistent with the changes in mRNA levels, there was a threefold increase in 4‐nitrophenol–UDP‐glucuronosyltransferase activity in 3‐methylcholanthrene–treated rat livers and in livers with preneoplastic nodules. In contrast to the 3‐methyl‐cholanthrene–inducible UDP‐glucuronosyltransferase mRNA, the androsterone–UDP‐glucuronosyltransferase mRNA was abundant in the liver and nearly absent in the kidney; its concentration was not increased after 3‐methylcholanthrene administration or in preneoplastic nodules. Immunocytochemical studies using an antiserum that recognizes androsterone‐ testosterone– and bilirubin–UDP‐glucuronosyltransferase isoforms did not show any increase of the concentration of these antigens in preneoplastic nodules. Similarly, activities for androsterone, testosterone and bilirubin also did not increase after 3‐methylcholanthrene

ISSN:0270-9139    

DOI:10.1002/hep.1840130107

出版商:W.B. Saunders    

年代:1991

数据来源: WILEY

摘要:

AbstractCell‐CAM 105 has been identified as a cell adhesion molecule based on the ability of anti‐cell‐CAM 105 monospecific Fab fragments to inhibit the reaggregation of rat hepatocytes. Because of its adhesive properties, it was expected that cell‐CAM 105 would be present on the lateral cell surface where adhesive interactions predominate. Paradoxically, however, immunofluorescence analysis of frozen sections of rat liver using specific monoclonal antibodies indicated that cell‐CAM 105 was present exclusively in the bile canalicular domain of the rat hepatocyte where there is no intercellular adhesion. To more precisely define thein situlocalization of cell‐CAM 105, immunoperoxidase labeling and electron microscopy were used to examine intact and mechanically dissociated liver tissue. Results showed that when accessibility was provided by mechanical dissociation of perfusion fixed liver tissue, cell‐CAM 105 could be detected in the pericanalicular region of lateral membranes. In contrast, when hepatocytes were labeled after incubationin vitrounder conditions used during adhesion assays to induce reaggregation, cell‐CAM 105 rapidly redistributed to all areas of the plasma membrane. Immunofluorescence analysis of primary hepatocyte cultures further revealed that cell‐CAM 105 and two other bile canalicular proteins relocalized to discrete domains reminiscent of bile canaliculi, whereas cell‐CAM 105 was also present in areas of intercellular contact. Serial section electron microscopy analysis of well‐defined, cross‐sectional profiles of bile canaliculi suggested the presence of cell‐CAM 105—positive membrane folds that extended along the length of the bile canalicular border. In sections from livers in which calcium‐dependent adhesive contacts had been disrupted by treatment with ethylenediamine tetraacetate, intact bile canaliculi were found that remained attached only by these border folds. The implications of these results are discussed with regard to a possible role for cell‐CAM 105 in bile canalicular format

ISSN:0270-9139    

DOI:10.1002/hep.1840130108

出版商:W.B. Saunders    

年代:1991

数据来源: WILEY

摘要:

AbstractThe relevance of the recently described membrane‐bound form of the HBe protein for the antiviral immune response was examined. The data show that antibodies in anti‐HBe, but not in anti‐HBc—positive human sera efficiently bind to the membrane expressed HBe. No evidence was obtained that the HBc can reach the cell surface in a form that can be detected with human antibodies. The findings suggest that the decline of virus titer that is usually observed after seroconversion from HBe to anti‐HBe might be the result of an antibody‐mediated elimination of infected cells. (HEPATOLOGY199

ISSN:0270-9139    

DOI:10.1002/hep.1840130109

出版商:W.B. Saunders    

年代:1991

数据来源: WILEY

摘要:

AbstractNon‐bile‐salt cholephilic organic anions are efficiently taken up by the liver. Recent work from our group has suggested the possible importance of relative hydrophobicity among various organic anions in hepatic uptake. To further validate and clarify this, we studied hepatic extraction of five different cholephilic dyes using the isolated perfused rat liver in single‐pass mode. Albumin binding affinities and capacities for each of the ligands were measuredin vitroto permit evaluation ofin vivointeractions for each of them over a spectrum of unbound ligand concentrations. As expected, a strong positive correlation was found between ligand hydrophobicity and the relative degree of albumin binding affinity and capacity. Using appropriate experimental conditions, we also found a strong positive correlation between hepatic extraction efficiency for a given ligand and both its hydrophobicity and its unbound concentration. These data indicate that where the unbound ligand concentration is significant, the greater the ligand hydrophobicity, the greater is its efficiency of hepatic extraction. We conclude that hepatic extraction efficiency for non‐bile‐salt cholephilic organic anions depends on a combination of ligand hydrophilic/hydrophobic balance and the availability of the unbound ligand for uptake. (HEPATOLOGY1991;

ISSN:0270-9139    

DOI:10.1002/hep.1840130110

出版商:W.B. Saunders    

年代:1991

数据来源: WILEY

摘要:

AbstractTrihydroxy bile acids with differing nonsterol chain length and charge were synthesized to define the effect of these parameters on the ability to competitively inhibit the Na+‐dependent uptake of14C taurocholate into isolated rat hepatocytes. Compounds with long side chains (≥ 0.8 nm) beyond carbon‐17 of the sterol nucleus and carrying a negative charge or no charge were potent inhibitors. Introduction of a positive charge into the side chain weakened inhibition. When the length of the chain beyond carbon‐17 fell below about 0.7 nm, charge still influenced inhibitory potency, but the effect was reversed and positively‐charged chains yielded slightly greater inhibition than negatively‐charged chains. From these results one may postulate a positively‐charged cell surface domain extending outward from a point about 0.7 nm from the sterol nucleus receptor region. Up to about 0.7 nm from the sterol nucleus receptor region one might postulate a negative cell surface charge to account for the weaker inhibitory potency of compounds with short negatively‐charged chains. Nonetheless, a short chain, regardless of charge, weakened inhibition, suggesting that a long negatively‐charged side chain is necessary to orient the sterol moiety for optimal receptor fit. These data confirm that the Na+‐dependent taurocholate transport site is sensitive to alterations of side chain charge and length and emphasize the importance of structure when designing bile acid analogs to probe taurocholate transport mechanisms. (HEPAT

ISSN:0270-9139    

DOI:10.1002/hep.1840130111

出版商:W.B. Saunders    

年代:1991

数据来源: WILEY