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Stem cell properties and repopulation of the rat liver by fetal liver epithelial progenitor cells.

The potential of embryonal day (ED) 14 fetal liver epithelial progenitor (FLEP) cells from Fischer (F)344 rats to repopulate the normal and retrorsine-treated liver was studied throughout a 6-month period in syngeneic dipeptidyl peptidase IV (DPPIV-) mutant F344 rats. In normal liver, FLEP cells formed: 1) hepatocytic clusters ranging in size up to approximately 800 to 1000 cells; 2) bile duct structures connected to pre-existing host bile ducts; and 3) mixed clusters containing both hepatocytes and bile duct epithelial cells. Liver repopulation after 6 months was moderate (5 to 10%). In retrorsine-treated liver, transplanted cells formed large multilobular structures containing both parenchymal and bile duct cells and liver repopulation was extensive (60 to 80%). When the repopulating capacity of ED 14 FLEP cells transplanted into normal liver was compared to adult hepatocytes, three important differences were noted: 1) FLEP cells continued to proliferate at 6 months after transplantation, whereas adult hepatocytes ceased proliferation within the first month; 2) both the number and size of clusters derived from FLEP cells gradually increased throughout time but decreased throughout time with transplanted mature hepatocytes; and 3) FLEP cells differentiated into hepatocytes when engrafted into the liver parenchyma and into bile epithelial cells when engrafted in the vicinity of the host bile ducts, whereas adult hepatocytes did not form bile duct structures. Finally, after transplantation of ED 14 FLEP cells, new clusters of DPPIV+ cells appeared after 4 to 6 months, suggesting reseeding of the liver by transplanted cells. This study represents the first report with an isolated fetal liver epithelial cell fraction in which the cells exhibit properties of tissue-determined stem cells after their transplantation into normal adult liver; namely, bipotency and continued proliferation long after their transplantation.

Animals↗

Effect of diethylmaleate on liver extracellular glutathione levels before and after global liver ischemia in anesthetized rats.

Glutathione (GSH), present in a high concentration in the liver, serves important protective functions. We investigated the effect of lowered tissue GSH content, accomplished by diethylmaleate (DEM) administration, on liver extracellular GSH levels before and after global ischemia in anesthetized rats. Liver extracellular GSH levels were determined by microdialysis perfusion and an on-line high performance liquid chromatography system. Global liver ischemia was induced by ligation of the hepatic pedicles including the hepatic artery, portal vein, and bile duct. DEM (4 mmol/kg) significantly lowered both the liver tissue GSH levels (1.36 +/- 0.26 micromol/g wet wt vs 9.50 +/- 0.55 micromol/g wet wt for the untreated) and the liver extracellular GSH levels (4.3 +/- 2.4 microM vs 25.2 +/- 8.7 microM for the untreated). Global liver ischemia induced a dramatic increase in the liver extracellular GSH level. Although the liver tissue GSH level was lowered following DEM treatment, DEM administration did not affect significantly ischemia-induced elevation of extracellular GSH (when presented as fold increase relative to basal value). In conclusion, DEM showed a direct effect on liver extracellular GSH content in anesthetized rats. However, DEM treatment did not affect the relative release of GSH following global liver ischemia.

Anesthesia↗

Influence of liver hepatitis C virus RNA and hepatitis C virus genotype on FAS-mediated apoptosis after liver transplantation for hepatitis C.

BACKGROUND: Recurrent hepatitis C virus (HCV) infection after liver transplantation is characterized by a high level of intrahepatic HCV replication and more severe liver damage in case of genotype 1b infection. We investigated the involvement of apoptosis in recurrent HCV liver disease, and its possible links with histological findings, HCV genotype, liver HCV RNA level, and liver Fas mRNA level. METHODS: We studied 61 liver graft biopsy specimens from 25 patients transplanted for HCV-related cirrhosis. DNA fragmentation was determined semi-quantitatively by in situ end labeling. HCV RNA and liver Fas mRNA were determined in parallel by quantitative polymerase chain reaction, with ribosomal 28S RNA as internal standard. RESULTS: Apoptotic lesions were predominantly portal (nonhepatocytic) or lobular (hepatocytic). Both were correlated with serum aminotransferase levels. The degree of portal apoptosis correlated with acute rejection (P<0.001), although lobular apoptosis was associated with lobular hepatitis (P<0.02), and HCV genotype 1b (P=0.04). In multivariate analysis, liver Fas mRNA level independently correlated with HCV-related chronic active hepatitis (P=0.04), age (P=0.01), and liver HCV RNA level (P=0.0007). CONCLUSIONS: After liver transplantation, 1) apoptosis is involved in HCV-related liver damage; 2) HCV type 1b may induce more severe apoptotic lesions than other genotypes; and 3) Fas transcription may be up-regulated by intrahepatic HCV replication.

Apoptosis↗

Liver tumor gross margin identification and ablation monitoring during liver radiofrequency treatment.

PURPOSE: To determine whether tissue visible light spectroscopy (VLS) used during radiofrequency (RF) ablation of liver tumors could aid in detecting when tissue becomes adequately ablated, locate grossly ablated regions long after temperature and hydration measures would no longer be reliable, and differentiate tumor from normal hepatic tissue based on VLS spectral characteristics. MATERIALS AND METHODS: Studies were performed on human liver in vivo and animal liver ex vivo. In three ex vivo cow livers, RF-induced lesions were created at 80 degrees C. A 28-gauge needle embedded with VLS optical fibers was inserted alongside an RF ablation array, and tissue spectral characteristics were recorded throughout ablation. In one anesthetized sheep in vivo, a VLS needle probe was passed through freshly ablated liver lesions, and ablated region spectral characteristics were recorded during probe transit. In two human subjects, a VLS needle probe was passed through liver tumors in patients undergoing hepatic tumor resection without ablation, and tumor spectral characteristics were recorded during probe transit. RESULTS: In bovine studies, there was significant change in baseline absorbance (P < .0001) as a result of increased light scattering as liver was ablated. Liver exhibited native differential absorbance peaks at 550 nm that disappeared during ablation, suggesting that optical spectroscopy detects markers of tissue altered during ablation. In sheep, liver gross ablation margins were clearly defined with millimeter resolution during needle transit through the region, suggesting that VLS is sensitive to gross margins of ablation, even after the temperature has normalized. In humans, absorbance decreased as the needle passed from normal tissue into tumor and normalized after emerging from the tumor, suggesting that absence of native liver pigment may serve as a marker for the gross margins and presence of tumors of extrahepatic origin. CONCLUSIONS: In human subjects, VLS during RF liver tumor ablation depicted gross hepatic tumor margins in real time; in animal subjects, VLS achieved monitoring of when and where RF ablation endpoints were achieved, even long after the tissue cooled. Real-time in vivo monitoring and treatment feedback may be possible with the use of real-time VLS sensors placed along side of, or embedded into, the RF probe, which can then be used as an adjunct to standard imaging during tumor localization and RF ablation treatment.

Adenocarcinoma↗

In situ hypothermic perfusion of the liver versus standard total vascular exclusion for complex liver resection.

SUMMARY BACKGROUND DATA: We compare the results of liver resection performed under in situ hypothermic perfusion versus standard total vascular exclusion (TVE) of the liver <60 minutes and > or =60 minutes in terms of liver tolerance, liver and renal functions, postoperative morbidity, and mortality. The safe duration of TVE is still debated. Promising results have been reported following TVE associated with hypothermic perfusion of the liver with durations of up to several hours. The 2 techniques have not been compared so far. METHODS: The study population includes 69 consecutive liver resections under TVE <60 minutes (group TVE<60', 33 patients), > or =60 minutes (group TVE> or =60', 16 patients), and in situ hypothermic perfusion (group TVEHYOPOTH, 20 patients). Liver tolerance (peaks of transaminases), liver and kidney function (peak of bilirubin, minimum prothrombin time, and peak of creatinine), morbidity, and in-hospital mortality were compared within the 3 groups. RESULTS: The postoperative peaks of aspartate aminotransferase (IU/L) and alanine aminotransferase (IU/L) were significantly lower (P[r] < 0.05) in group TVE HYPOTH (450 +/- 298 IU/L and 390 +/- 391 IU/L) compared with the groups TVE<60' (1000 +/- 808; 853 +/- 743) and TVE> or =60' (1519 +/- 962; 1033 +/- 861). In the group TVEHYPOTH, the peaks of bilirubin (micromol/L) (84 +/- 31), creatinine (micromol/L) (75 +/- 22), and the number of complications per patient (1.2 +/- 0.9) were comparable to those of the group TVE<60' (80 +/- 111; 109 +/- 77; and 0.8 +/- 1.1 respectively) and significantly lower to those of the group TVE> or =60' (196 +/- 173; 176 +/- 176, and 2.6 +/- 1.8). In-hospital mortality rates were 1 in 33, 2 in 16, and 0 in 20 for the groups TVE<60', TVE> or =60', and TVEHYOPOTH, respectively, and were comparable. On multivariate analysis, the size of the tumor, portal vein embolization, and a planned vascular reconstruction were significantly predictive of TVE > or =60 minutes. CONCLUSIONS: Compared with standard TVE of any duration, hypothermic perfusion of the liver is associated with a better tolerance to ischemia. In addition, compared with TVE > or =60 minutes, it is associated with better postoperative liver and renal functions and a lower morbidity. Predictive factors for TVE > or =60 minutes may help to indicate hypothermic perfusion of the liver.

Alanine Transaminase↗

Hepatic stellate cells in hepatitis C patients: relationship with liver iron deposits and severity of liver disease.

BACKGROUND AND AIM: To determine the relationship between hepatic stellate cell (HSC) populations and severity of liver disease and liver iron deposits in patients with chronic hepatitis C virus (HCV). We also studied the relationship between iron cellular distribution and HSC population and the role of HFE mutations in the determination of iron deposits. METHODS: Forty-nine chronic HCV patients with varying degrees of liver damage and liver iron deposits were studied. A liver biopsy was scored for histology activity index (HAI), fibrosis and iron deposits. The number of HSC in the liver was evaluated by an immunohistochemical double-staining method to identify glial fibrillary acid protein (GFAP) and smooth muscle alpha-actin (alpha-SMA). RESULTS: The HSC population was significantly higher in HCV patients than in normal controls and was predominant in zones 1 and 3. Liver iron deposits were observed in 49% of patients and were mild/moderate in most cases. We found a significantly higher number of GFAP and alpha-SMA positive cells in patients with liver iron deposits compared with those without iron deposits, and a positive correlation between liver iron scores and number (%) of GFAP and alpha-SMA positive cells. We observed a significantly higher number of GFAP and alpha-SMA positive cells in moderate/severe hepatitis than in minimal/mild hepatitis, and a positive correlation between GFAP and alpha-SMA positive cells and HAI and fibrosis scores. CONCLUSIONS: Liver iron deposits in chronic HCV are common and are associated with activation of HSC. Thus, even mild iron deposits might stimulate HSC and contribute to liver damage.

Adolescent↗

Comparison and in vivo relevance of two different in vitro head space metabolic systems: liver S9 and liver slices.

In vitro systems of high biological organization, e.g. containing intact hepatocytes, have been considered as more reliable for metabolic studies and in vivo predictions of toxicokinetics than subcellular systems. For this reason, the kinetics and metabolism of low-molecular-weight volatile chemicals, i.e. head space elimination of substrate and formation of metabolites, were compared in liver S9 and in liver slices. Two substrates, toluene and n-hexane, were used as they represent differences in metabolic pathways and physical-chemical properties. The two systems responded similarly to diethyldithiocarbamate inhibition and acetone inhibition/induction of cytochrome P-450 mediated metabolism. In contrast to liver S9, liver slices did not respond adequately to phenobarbital induction raising the question of substrate availability for P-450 enzymes in liver slices. Liver slices appeared to be superior to liver S9 when specific metabolic pathways involving phase II enzymes were investigated. However, liver S9 seemed to be at least as good as liver slices for estimation of total metabolic rate constants (Km, Vmax) as a basis for in vivo predictions. As the head space liver S9 system is faster and easier to operate than liver slices, it is a promising screening tool for the metabolism of volatile compounds and metabolic interactions.

Acetone↗

Liver adenomatosis. An entity distinct from liver adenoma?

From 1979 to 1984, we followed the cases of 3 men (aged 13, 31, and 75 yr) and 2 women (aged 38 and 45 yr who had never used oral contraceptives) suffering from liver adenomatosis, an uncommon lesion consisting of numerous benign adenomas in an otherwise normal hepatic parenchyma. During the same period, we observed 20 cases of liver adenoma (one tumor in 18 patients and two tumors in 2 patients). From these cases and the review of previously reported cases of liver adenomatosis and series of liver adenoma, the following distinctive characteristics of these two benign conditions of the liver can be outlined: liver adenomatosis affects men and women, whereas liver adenoma predominantly affects women; liver adenomatosis is unrelated, whereas liver adenoma is closely related, to oral contraceptive use; increases in serum alkaline phosphatase and gamma-glutamyl transpeptidase are common in liver adenomatosis, but are uncommon in liver adenoma.

Adenoma↗

Phosphorylation and inactivation of liver glycogen synthase by liver protein kinases.

A rapid method for purifying glycogen synthase a from rat liver was developed and the enzyme was tested as a substrate for nine different protein kinases, six of which were isolated from rat liver. The enzyme was phosphorylated on a 17-kDa CNBr fragment to approximately 1 phosphate/87-kDa subunit by phosphorylase b kinase from muscle or liver with a decrease in the activity ratio (-Glc-6-P/+Glc-6-P) from 0.95 to 0.6. Calmodulin-dependent glycogen synthase kinase from rabbit liver produced a similar phosphorylation pattern, but a smaller activity change. The catalytic subunit of beef heart cAMP-dependent protein kinase incorporated greater than 1 phosphate/subunit initially into a 17-kDa CNBr peptide and then into a 27-30-kDa CNBr peptide, with an activity ratio decrease to 0.5. Glycogen synthase kinases 3, 4, and 5 and casein kinase 1 were purified from rat liver. Glycogen synthase kinase 3 rapidly phosphorylated liver glycogen synthase to 1.5 phosphate/subunit with incorporation of phosphate into 3 CNBr peptides and a decrease in the activity ratio to 0.3. Glycogen synthase kinase 4 produced a pattern of phosphorylation and inactivation of liver synthase which was very similar to that caused by phosphorylase b kinase. Glycogen synthase kinase 5 incorporated 1 phosphate/subunit into a 24-kDa CNBr peptide, but did not alter the activity of the synthase. Casein kinase 1 phosphorylated and inactivated liver synthase with incorporation of phosphate into a 24-kDa CNBr peptide. This kinase and glycogen synthase kinase 4 were more active against muscle glycogen synthase. Calcium-phospholipid-dependent protein kinase from brain phosphorylated liver and muscle glycogen synthase on 17- and 27-kDa CNBr peptides, respectively. However, there was no change in the activity ratio of either enzyme. The following conclusions are drawn. 1) Liver glycogen synthase a is subject to multiple site phosphorylation. 2) Phosphorylation of some sites does not per se control activity of the enzyme under the assay conditions used. 3) Liver contains most, if not all, of the protein kinases active on glycogen synthase previously identified in skeletal muscle.

Animals↗

Oxygen measurement and arteriography in the rat and guinea pig liver after artery ligation in the liver hilus.

There are differences in biological behavior of liver in different species of animals. The most impressive and easily reproduceable examples are the different reactions of rat and guinea pigs livers: The guinea pig cannot withstand more than a few hours the interruption of the Ductus Choledochus, it cannot survive complete ligation of liver arteries plus many anastomosis. Furthermore it is unable to withstand infections in the liver and intestine after operations of the liver. The rat however can withstand ligations of the Ductus Choledochus, even for months, and is not harmed by complete dissection of liver hilus with double ligations of Arteria Hepatica Propria and Communis, including the few anastomoses. Infections of liver after laparotomias are unknown in rats. To study these differences the Po 2 values of liver were measured and checked against angiographies and biological tests. In dearterialised rat liver the reduced Po 2 values and biological tests rose parallel with the reaterialisation for weeks. In guinea pigs the Po 2 values were not lower than in the rats in the short surviving time measured. The Po 2 reduction seems in both species the same. The rat liver is able to adapt -, the liver of guinea pig is not.

Angiography↗

[DNA and proteins in the liver of rats fed with corn: the importance of expressing the concentration of liver proteins in relation to DNA].

Variations in liver DNA and protein content were studied in rats fed common corn (diet I) and in another group of rats fed a diet made of corn starch ("maicena"), "chuño" (dried potato), sugar and fat (diet II). The results were compared with those from a control group fed a balanced diet with adequate protein. Diets were administered after weaning, for a period of 90 days. Animals on diets I and II showed an increase in the DNA concentrations per g of liver. Liver protein concentration was expressed in three forms: as mg of protein per g of liver, mg of protein per mg of DNA and mg of protein in the total liver weight. Animals raised on diet II had a decrease in liver protein, which was evident regardless of the way of expressing the results. On the other hand, in rats raised on corn (diet I), the results expressed as mg of protein per g of liver did not show a decrease in liver proteins, while the other two ways of expressing the results demonstrated a decrease in liver protein. It seems that the most trustworthy way to express liver protein concentration is as mg of protein per mg of DNA. The importance of expressing the results of liver protein concentrations as a function of DNA is emphasized and its usefulness demonstrated and discussed.

Animals↗

The frequency of 4977 base pair deletion of mitochondrial DNA in various types of liver disease and in normal liver.

Using a polymerase chain reaction (PCR) method, we tested for the hepatic mitochondrial DNA (mtDNA) deletion in 40 hepatic tumors (28 hepatocellular carcinomas [HCCs], 9 other malignant tumors, and 3 benign tumors) and in the livers of 71 patients, including 16 pediatric patients with end-stage liver disease who underwent living related donor liver transplantation and 16 liver donors. A 4977 base pair (bp) deletion of mtDNA was detected in 36 of 55 specimens of non-tumor portions of adult liver (65.5%). However, none of the specimens obtained from cirrhotic livers of the 16 pediatric patients younger than 13 years of age had the 4977 bp deletion. The frequency of mtDNA deletion was significantly decreased compared with normal liver in HCCs (7 of 28) and other malignant liver tumors (2 of 9). The frequency of this deletion was unrelated to the presence of liver cirrhosis, patient's gender, hepatitis B virus surface antigen status, and hepatitis C virus antibody status.

Adolescent↗

Characteristics of serum IgA and liver IgA deposits in alcoholic liver disease.

Patients with alcoholic liver disease frequently reveal an increase in IgA serum concentration and IgA deposits in a continuous pattern along hepatic sinusoids. We investigated whether the hepatic IgA deposits are a passive reflection of changes in concentration or composition of IgA in the circulation, or represent a distinct effect of alcohol on the liver. Forty-one patients with alcoholic liver disease (daily alcohol intake at least 50 gm for more than five consecutive years) were compared with 41 patients with nonalcoholic liver disease. Patients in both groups were matched for serum IgA and histopathological changes in the liver biopsy. IgA deposits in the liver were found in 78% of the alcoholic patients and in 12% of the nonalcoholic patients. The presence of deposits was not related to histopathological changes in the liver or to the serum IgA concentration. In serum IgA subclass distribution, alcoholic patients differed from nonalcoholic patients by a slight but significant shift to IgA2; in contrast, the hepatic IgA deposits in alcoholic patients were almost of the IgA1 subclass. Serum secretory component (which is an equivalent of serum secretory IgA) was elevated in both alcoholic and nonalcoholic patients; patients with a liver biopsy revealing hepatitis showed the highest level. In contrast, the hepatic deposits did not contain secretory component. We conclude that the continuous deposits of IgA along liver sinusoids are not a passive reflection of changes in concentration or composition of circulating IgA, but may represent a distinct effect of alcohol on the liver related to the role of this organ in IgA metabolism.

Biopsy, Needle↗

Distribution of vitronectin in plasma and liver tissue: relationship to chronic liver disease.

To clarify the clinical significance of vitronectin, we compared the concentration of plasma vitronectin with serum fibrous markers and liver function test values in patients with chronic liver diseases. We also evaluated the vitronectin content in the liver by means of enzyme-linked immunosorbent assay and the localization of vitronectin in liver tissue with enzyme immunohistochemistry. In chronic liver disease, the concentration of plasma vitronectin was significantly lower than that in healthy controls, being related to the severity of liver disease. The plasma levels of vitronectin showed no correlation to fibrous markers but a significant correlation with those of serum albumin and prothrombin time. On the other hand, the content of vitronectin in liver tissue was significantly increased in chronic liver disease compared with that in normal controls. In the normal liver, vitronectin was observed in the portal area by light microscopy. In chronic hepatitis and cirrhosis, vitronectin was found in the connective tissue around the portal and central veins and in the areas of piecemeal and focal necrosis. These findings suggested that vitronectin is deposited in injured tissue through the process of repair and fibrosis and plays an important role as an adhesive protein. Moreover, the lower levels of plasma vitronectin in chronic liver disease may be due to its decreased synthesis, deposition or both in injured tissue.

Adult↗

End-stage liver disease as the only consequence of a mitochondrial respiratory chain deficiency: no contra-indication for liver transplantation.

UNLABELLED: The prerequisite for liver transplantation as a therapeutic option for inherited metabolic diseases should be that the enzyme defect, being responsible for the major clinical (hepatic and/or extra-hepatic) abnormalities, is localised in the liver. Furthermore, no adequate dietary or pharmacological treatment should be available or such treatment should have an unacceptable influence on the quality of life. We report an infant, who developed end-stage liver disease with persistent lactic acidaemia in his first months of life. Analysis of the mitochondrial respiratory chain in liver tissue revealed a combined partial complex I and IV deficiency. No extra-hepatic involvement could be demonstrated by careful screening for multiple organ involvement, including analysis of the mitochondrial respiratory chain in muscle tissue and cultured skin fibroblasts. The boy received a reduced size liver graft at the age of 8 months. He recovered successfully. Almost 5 years after transplantation he is in good clinical condition. No clinical or biochemical signs of any organ dysfunction have been demonstrated. The considerations on which basis it was decided that there was no contra-indication to perform liver transplantation in this patient are discussed. CONCLUSION: The possibility of a mitochondrial respiratory chain deficiency should be considered in liver disease of unknown origin prior to liver transplantation. Liver transplantation is a therapeutic option in mitochondrial respiratory chain deficiency-based end-stage liver disease provided that extra-hepatic involvement is carefully excluded.

Child, Preschool↗

Liver regeneration in a retrorsine/CCl4-induced acute liver failure model: do bone marrow-derived cells contribute?

BACKGROUND/AIMS: Adult bone marrow contains progenitors capable of generating hepatocytes. Here a new liver failure model is introduced to assess whether bone marrow-derived progeny contribute to liver regeneration after acute hepatotoxic liver failure. METHODS: Retrorsine was used to inhibit endogenous hepatocyte proliferation, before inducing acute liver failure by carbon tetrachloride. Bone marrow chimeras were generated before inducing liver failure to trace bone marrow-derived cells. Therefore, CD45 and major histocompatibility complex (MHC) class I dimorphic rat models were applied. RESULTS: Early after acute liver failure a multilineage inflammatory infiltrate was observed, mainly consisting of granulocytes. In long-term experiments small numbers of CD90+/CD45- cells of donor origin occurred in clusters associated with portal triads. Bone marrow cell infusion was not able to enhance liver regeneration. Cellular hypertrophy was the predominant way of liver mass regeneration in models applying retrorsine. CONCLUSIONS: Retrorsine pretreatment did not affect sensitivity for carbon tetrachloride. A multilineage inflammatory infiltrate was observed in rats whether pretreated with retrorsine or not. Few donor cells co-expressing CD90 (THY 1) were present in recipient livers, which may resemble donor-derived hematopoietic progenitors or oval cells. No other donor cells within liver parenchyma were detected. This is in contrast to other cell infusion models of acute cell death.

Animals↗

Increased liver echogenicity at ultrasound examination reflects degree of steatosis but not of fibrosis in asymptomatic patients with mild/moderate abnormalities of liver transaminases.

AIMS: To investigate whether hyperechogenicity of liver can reliably be interpreted as liver steatosis and if any concomitant or isolated fibrosis can be disclosed. PATIENTS AND METHODS: A series of 165 patients with no signs or symptoms of liver disease referred because of slightly to moderately raised aminotransferases (alanine aminotransferase and/or aspartate aminotransferase 0.7-5.0 microkat/l) for more than 6 months were prospectively investigated with a comprehensive laboratory profile, ultrasound examination of liver and percutaneous liver biopsy Fibrosis was assessed quantitatively and according to Metavir. Steatosis was graded as none, mild, moderate or severe. RESULTS: Of 98 (59.4%) patients with raised echogenicity, 85 (86.7%) had liver steatosis of at least moderate degree, 9 patients with same degree of steatosis had normal echogenicity and 13 patients with no or only mild steatosis had a hyperechogenic liver (sensitivity 0.90, specificity 0.82, positive predictive value 0.87, negative predictive value 0.87). About the same relations were found regardless of body mass index and degree of fibrosis. With increased echogenicity together with high attenuation (n = 591 and reduced portal vessel wall distinction (n = 79), positive predictive value increased to 0.93 and 0.94, respectively. Quantitatively assessed fibrosis (mean +/- SD) was 3.2 +/- 4.6% of biopsy area with normal and 2.3 +/- 1.8% with raised echogenicity (ns). Echogenicity was normal in 5 out of 9 patients with septal fibrosis and in 4 out of 6 patients with cirrhosis. Any structural, non-homogenous findings at ultrasound were not associated with architectural fibrotic changes and none had nodular contours of liver surface. CONCLUSIONS: Assessment of liver echogenicity is of value for detection or exclusion of moderate to pronounced fatty infiltration (correct classification 86.6%) but cannot be relied upon in diagnosing fibrosis, not even cirrhosis in asymptomatic patients with mild to moderately elevated liver transaminases.

Adult↗

Early down-regulation of cytochrome P450 3A and 2E1 in the regenerating rat liver is not related to the loss of liver mass or the process of cellular proliferation.

AIMS/BACKGROUND: Conflicting data have been reported concerning the modification of cytochrome P450 expression in the regenerating liver. Ligation of branches of the portal vein (PBL) perfusing 70% of the liver parenchyma, which produces regeneration and atrophy within the same liver, constitutes an ideal model to study the relative specificity of the early events in the regenerating liver and their relationship to the loss of liver mass. METHODS: In this PBL model and in sham models, we studied the expression and the metabolic activities of two major cytochromes, CYP3A and CYP2E1, and the expression of inducible nitric oxide synthase protein (iNOS). They were simultaneously measured in the atrophying and regenerating liver lobes following PBL using Western Blot and HPLC methods. RESULTS: The metabolic activities of both cytochromes were transiently and simultaneously down-regulated in the regenerating and atrophying lobes during the first 2-5 h after PBL. No significant modification was observed at the protein level. In contrast, iNOS protein was significantly induced in both lobes. Similar results were observed after sham operation. CONCLUSIONS: The reduction of these CYP activities in both lobes after PBL and in sham livers suggests that other mechanisms than the regenerating process itself or the reduction of the liver mass might account for such down-regulation during the early phase of liver regeneration. The activation of nitric oxide (NO) and/or pro-inflammatory cytokine production provides clues to pathways liable to affect the CYP activities in the regenerating liver.

Animals↗