The predictive ability of serum α-fetoprotein for hepatocellular carcinoma is linked with the characteristics of the target population at surveillance

BACKGROUND

Serum alpha-fetoprotein (AFP) is the most important tumor marker for hepatocellular carcinoma (HCC). The reported predictive accuracy of AFP for HCC widely varied. This study investigated the factors contributory to the heterogeneity of the ability of AFP to detect HCC.

METHODS

A total of 1,135 patients were categorized into four groups: HCC undergoing surgical resection (n = 248), chronic hepatitis B (CHB, n = 413), chronic hepatitis C (CHC, n = 207), and liver cirrhosis (LC, n = 267). The area under the receiver operating characteristic curve (AUC) was estimated in different combinations.

RESULTS

The AUC was the highest when HCC patients were co-analyzed with patients with LC (0.805), followed by co-analyzing patients with CHB (0.797) and CHC (0.740). The optimal cutoffs for AFP were between 26 and 32 ng/ml. Patients with tumor size </=3 cm had a lower positive predictive value (PPV, 30%) compared to patients with tumor size >3 cm (46%), and HBsAg-negative and anti-HCV-positive patients had the lowest PPV (38%) compared to other groups (60%, 100%, and 82%) at a cutoff at 20 ng/ml. The AUC was lower for hepatitis B-negative subjects (0.684 and 0.509), compared to hepatitis B-positive subjects (0.826 and 0.806) stratified by the status of HCV. Elevated ALT >80 U/L and HCC independently predicted increased (>20 ng/ml) AFP levels.

CONCLUSIONS

Serum AFP had a fairly stable predictive accuracy for HCC, with an optimal cutoff around 30 ng/ml. ALT level, viral status, and tumor size may significantly confound its ability to detect HCC.

Role of hepatic nitric oxide synthases in rats with thioacetamide-induced acute liver failure and encephalopathy

BACKGROUND

Hepatic encephalopathy is neuropsychiatric derangement secondary to hepatic decompensation or portal-systemic shunting. Nitric oxide (NO) synthase inhibition aggravates encephalopathy and increases mortality in rats with thioacetamide (TAA)-induced acute liver failure, suggesting a protective role of NO. This study investigated the roles of endothelium-derived constitutive NO synthase (eNOS) and inducible NOS (iNOS) in the liver of rats with fulminant hepatic failure and encephalopathy.

METHODS

Male Sprague-Dawley rats (300-350 g) were randomized to receive TAA 350 mg/kg/day, by intraperitoneal injection or normal saline for 3 days. Severity of encephalopathy was assessed with the Opto-Varimex animal activity meter. Plasma levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, and bilirubin were measured. Hepatic iNOS and eNOS RNA and protein expressions were assessed by reverse transcription-polymerase chain reaction and Western blot analyses, respectively.

RESULTS

The TAA group showed lower motor activity counts than the normal saline group. Hepatic eNOS, but not iNOS, mRNA and protein expressions were enhanced in the TAA group. In addition, hepatic eNOS mRNA expression was negatively correlated with total movement but positively correlated with ALT and AST. Protein expression of hepatic eNOS was positively correlated with ALT, AST and bilirubin.

CONCLUSION

Upregulation of hepatic eNOS was observed in rats with TAA-induced fulminant hepatic failure and encephalopathy, which might play a regulatory role.

Detrimental effects of nitric oxide inhibition on hepatic encephalopathy in rats with thioacetamide-induced fulminant hepatic failure: role of nitric oxide synthase isoforms

BACKGROUND

Hepatic encephalopathy is a complex neuropsychiatric syndrome. A previous study showed that chronic nitric oxide (NO) inhibition aggravated the severity of encephalopathy in thioacetamide (TAA)-treated rats. The present study investigated the relative contribution of NO synthase (NOS) isoforms on the severity of hepatic encephalopathy in TAA-treated rats.

METHOD

Fulminant hepatic failure was induced in male Sprague-Dawley rats by intraperitoneal injection of TAA (350 mg/kg/day) for 3 days. Rats were divided into three groups to receive N(omega)-nitro-L-arginine methyl ester (L-NAME, a non-selective NOS inhibitor, 25 mg/kg/day in tap water), L-canavanine (an inducible NOS inhibitor, 100 mg/kg/day via intraperitoneal injection) or normal saline (N/S) from 2 days prior to TAA administration and lasting for 5 days. Severity of encephalopathy was assessed by the counts of motor activity. Plasma levels of tumor necrosis factor-alpha (TNF- alpha) were determined by enzyme-linked immunosorbent assay (ELISA), and total bilirubin, alanine aminotransferase (ALT) and creatinine were determined by colorimetric assay.

RESULTS

Compared with L-canavanine or N/S-treated rats (0% and 4%, respectively), the mortality rate was significantly higher in rats receiving L-NAME administration (29%, P < 0.005). Inhibition of NO created detrimental effects on the counts of motor activities (P < 0.05). Rats treated with L-NAME had significantly higher plasma levels of total bilirubin, ALT, creatinine and TNF- alpha as compared with rats treated with L-canavanine or N/S (P < 0.01).

CONCLUSION

Chronic L-NAME administration, but not L-canavanine, had detrimental effects on the severity of hepatic damage and motor activities in TAA-treated rats. These results suggest that constitutive NOS activities play a major protective role in rats with fulminant hepatic failure.

Evidence against a role for endotoxin in the hepatic encephalopathy of rats with thioacetamide-induced fulminant hepatic failure

BACKGROUND AND AIMS

Endotoxin has been proposed to participate in the development of hepatic encephalopathy. However, there is no published data concerning the effects of endotoxin neutralization on the degree of hepatic encephalopathy. The present study investigated the effect of chronic intraperitoneal injection of polymyxin B, a neutralizing antagonist of endotoxin, on hepatic encephalopathy in rats with thioacetamide (TAA)-induced fulminant hepatic failure.

METHODS

Male Sprague-Dawley rats weighing 300-350 g were used. Fulminant hepatic failure was induced by intraperitoneal injection of TAA (350 mg/kg/day) for 3 days. Two series of rats were designed to compare the effects of low dose (0.1 mg) or high dose (0.2 mg) intraperitoneal polymyxin B administration versus normal saline (NS) on hepatic encephalopathy. The injection was twice daily started from 2 days prior to TAA administration and lasted for 5 days. Severity of encephalopathy was assessed by the counts of motor activity in an Opto-Varimex animal activity meter. Plasma levels of endotoxin and tumor necrosis factor-alpha (an index of liver injury) were measured by Limulus assay and the ELISA method, respectively.

RESULTS

Neutralization of endotoxin by either low dose or high dose polymyxin B administration did not significantly alleviate the degree of hepatic encephalopathy, as represented by the counts of motor activities (P > 0.05). Plasma levels of endotoxin and tumor necrosis factor-alpha were comparable between rats treated with polymyxin B or NS (P > 0.05).

CONCLUSION

Our findings do not support the notion that endotoxin plays a major role in the pathogenesis of hepatic encephalopathy in rats with TAA-induced fulminant hepatic failure.

Prostacyclin inhibition by indomethacin aggravates hepatic damage and encephalopathy in rats with thioacetamide-induced fulminant hepatic failure

AIM: Vasodilatation and increased capillary permeability have been proposed to be involved in the pathogenesis of acute and chronic form of hepatic encephalopathy. Prostacyclin (PGI₂) and nitric oxide (NO) are important contributors to hyperdynamic circulation in portal hypertensive states. Our previous study showed that chronic inhibition of NO had detrimental effects on the severity of encephalopathy in thioacetamide (TAA)-treated rats due to aggravation of liver damage. To date, there are no detailed data concerning the effects of PGI₂ inhibition on the severity of hepatic encephalopathy during fulminant hepatic failure.

METHODS: Male Sprague-Dawley rats weighing 300-350 g were used. Fulminant hepatic failure was induced by intraperitoneal injection of TAA (350 mg/(kg.d) for 3 d. Rats were divided into two groups to receive intraperitoneal injection of indomethacin (5 mg/(kg.d), n = 20) or normal saline (N/S, n = 20) for 5 d, starting 2 d before TAA administration. Severity of encephalopathy was assessed by the counts of motor activity measured with Opto-Varimex animal activity meter. Plasma tumor necrosis factor-α (TNF-α, an index of liver injury) and 6-keto-PGF_1α (a metabolite of PGI₂) levels were measured by enzyme-linked immunosorbent assay.

RESULTS: As compared with N/S-treated rats, the mortality rate was significantly higher in rats receiving indomethacin (20% vs 5%, P<0.01). Inhibition of PGI₂ created detrimental effects on total movement counts (indomethacin vs N/S: 438±102 vs 841±145 counts/30 min, P<0.05). Rats treated with indomethacin had significant higher plasma levels of TNF-α (indomethacin vs N/S: 22±5 vs 10±1 pg/mL, P<0.05) and lower plasma levels of 6-keto-PGF_1α (P<0.001), but not total bilirubin or creatinine (P>0.05), as compared with rats treated with N/S.

CONCLUSION: Chronic indomethacin administration has detrimental effects on the severity of encephalopathy in TAA-treated rats and this phenomenon may be attributed to the aggravation of liver injury. This study suggests that PGI₂ may provide a protective role in the development of fulminant hepatic failure.

The clinical experience of Chinese patients with Wilson's disease

BACKGROUND/AIMS

Wilson's disease has protean presentations. Most patients manifested as either hepatic or neurologic symptoms and signs initially. No study has investigated the predictor of presentation and differences in laboratory tests and survival between patients presented with hepatic or neurological disease so far.

METHODOLOGY

Forty-one patients with Wilson's disease were diagnosed between 1981 and 2002 at our hospital. Their clinical features at presentation and laboratory findings were retrospectively collected. Survival was calculated using the Kaplan-Meier analysis.

RESULTS

Twelve patients initially presented with hepatic symptoms including chronic hepatitis, complications of cirrhosis, and fulminant hepatic failure. Twenty-nine patients presented with neurological symptoms including tremor, dysarthria, ataxia, and psychiatric diseases. No specific factor identified could predict the initial presentations. Compared to patients with neurological symptoms, patients with hepatic disease had significantly higher serum levels of aminotransferase, ceruloplasmin, copper, and 24-hour urine copper excretion. There was no significant difference in survival between these two groups. Among the patients who died, the most common causes of death were fulminant hepatic failure and complications of cirrhosis.

CONCLUSIONS

Our results suggested that the overall survival did not differ significantly according to the initial presentations. There was no predictor found that could foretell the clinical course of Wilson's disease.

Prevalence of HBV precore/core promoter variants in the United States

Variants in the precore (G(1896)A) and core promoter (A(1762)T, G(1764)A) regions of hepatitis B virus (HBV) may be related to serum HBV DNA levels and severity of liver disease. The aims of this nationwide study were to determine the prevalence of HBV precore/core promoter variants in the United States and the association between these variants and patient demographics, HBV genotypes, serum HBV DNA level, and severity of liver disease. A total of 694 consecutive chronic HBV-infected patients seen in 17 U.S. liver centers during a 1-year period were enrolled. Demographic, clinical, and laboratory data were collected. Sera were tested for HBV genotypes as well as precore and core promoter variants by line-probe assays. Quantitative HBV DNA levels were determined using Cobas Amplicor HBV Monitor kits. Precore and core promoter variants were found in 27% and 44% of patients with chronic HBV infection in the United States. Precore and core promoter variants were more common in hepatitis B e antigen (HBeAg)-negative than in HBeAg-positive patients (precore, 38% vs. 9%; core promoter, 51% vs. 36%; respectively, P <.001). The prevalence of these variants was related to ethnicity, place of birth, and HBV genotypes. Patients with core promoter variants were more likely to have hepatic decompensation. Precore and/or core promoter variants were associated with higher serum HBV DNA levels in HBeAg-negative but not in HBeAg-positive patients. In conclusion, HBV precore and core promoter variants are not rare in the United States. Physicians should be aware of the existence of HBV precore and core promoter variants and the clinical condition of "HBeAg-negative chronic hepatitis."

Hepatitis B virus genotypes in the United States: results of a nationwide study

BACKGROUND & AIMS

Hepatitis B virus (HBV) genotypes may be related to severity of liver disease and treatment response. The aims of this nationwide study were to determine the prevalence of HBV genotypes in the United States and the association between HBV genotypes and patient demographics, mode of infection, and clinical status.

METHODS

A total of 694 consecutive chronic HBV-infected patients seen in 17 U.S. liver centers during a 1-year period were enrolled. Demographic, clinical, and laboratory data were collected. Sera were tested for HBV genotyping, precore, and core promoter variants by line-probe assays.

RESULTS

All 7 HBV genotypes (A-G) were found, with genotypes A and C the most common. The prevalence of HBV genotypes was different in different regions of the United States. A strong correlation was found between HBV genotypes and ethnicity. HBV genotype A was prevalent among white and black patients, whereas genotypes B and C were most common among Asian patients. The predominant genotype among patients born in the United States, Europe, the Far East, and Southeast Asia were A, D, C, and B, respectively. Genotypes A and C were associated with a higher prevalence of hepatitis B e antigen. Precore variant was detected in 27% of patients and core promoter variant in 44% of patients.

CONCLUSIONS

Our study suggests that the epidemiology of HBV infection in the United States may have changed over time as a result of immigration from countries with a high prevalence of HBV infection. HBV genotypes may account for the heterogeneity in disease manifestations among patients with chronic HBV infection.

Rapid and sensitive assays for determination of hepatitis B virus (HBV) genotypes and detection of HBV precore and core promoter variants

Hepatitis B virus (HBV) genotypes may influence HBeAg seroconversion rates, mutational patterns in the precore (PC) and core promoter (CP) regions, severity of liver disease, and response to antiviral treatment. Development of rapid, simple, and standardized assays to detect viral genotypes and common mutations in the PC and CP regions can accelerate research on the clinical significance of these variants. We aim to assess the accuracy of a line probe assay in determining HBV genotypes and detecting HBV PC and CP variants. HBV genotypes in 701 patients and PC and CP variants in 600 patients with chronic HBV infection from China and the United States were studied using the INNO-LiPA assay. All but one (99.9%) sample were classified by the genotyping assay. All eight genotypes, i.e., A to H, were found. The INNO-LiPA genotyping assay results were completely concordant with those of sequencing. Using the INNO-LiPA PC assay, 99.8 and 94.7% samples were classifiable in the PC and CP regions, respectively. The PC assay results were completely concordant with those of sequencing in all samples that showed either wild-type or variant sequence. The line probe assay was more sensitive in detecting mixtures than was direct sequencing. By INNO-LiPA, only 50 and 27% of the samples, with mixed wild-type and variant sequence in the PC and CP region, respectively, showed mixed sequence by direct sequencing. INNO-LiPA is rapid, sensitive, and reliable-thus enabling accurate determination of HBV genotypes and detection of PC and CP variants in a large population of patients.

Quantitative serum HBV DNA levels during different stages of chronic hepatitis B infection

The goals of this retrospective study were to determine whether there is a threshold hepatitis B virus (HBV) DNA value associated with spontaneous or antiviral therapy-related hepatitis B e antigen (HBeAg) clearance. We also investigated whether there is an HBV DNA value that can be used for differentiating inactive carriers from patients with HBeAg-negative chronic hepatitis B. HBV DNA levels in sequential serum samples of 165 Chinese patients with different stages of chronic HBV infection were quantified by a polymerase chain reaction (PCR)-based assay. Our results showed that almost all of the patients (89%) who remained HBeAg-positive had HBV DNA levels that were persistently above 10(5) copies/mL. Serum HBV DNA levels decreased by a mean of 3 log(10) in patients with HBeAg loss, but 51% had levels above 10(5) copies/mL at the time HBeAg first became undetectable. Mean serum HBV DNA levels were significantly lower in HBeAg-negative patients. HBV DNA value above 10(5) copies/mL would exclude all inactive carriers, but 45% of patients with HBeAg-negative chronic hepatitis would also be excluded if testing were only performed at presentation and 30% would be excluded if testing were performed on 3 occasions. In conclusion, serum HBV DNA levels decreased significantly in patients with HBeAg loss, but there was no threshold HBV DNA level associated with HBeAg clearance. Given the fluctuating course of HBeAg-negative chronic hepatitis, it is not possible to define a single cutoff HBV DNA value for differentiating inactive carriers from patients with HBeAg-negative chronic hepatitis.

HBV genotype B is associated with better response to interferon therapy in HBeAg(+) chronic hepatitis than genotype C

Hepatitis B virus (HBV) genotype and precore/core promoter mutations have been implicated in spontaneous and interferon alfa (IFN-alpha)-related hepatitis B e antigen (HBeAg) seroconversion. We performed a retrospective analysis of a previously reported randomized controlled trial to determine the effects of HBV genotype and precore/core promoter mutations on IFN-alpha response in patients with HBeAg-positive chronic hepatitis. Clinical data and stored sera from 109 (95%) patients in the original trial were analyzed. Seventy-three patients received IFN-alpha and 34 received no treatment (controls). Almost all patients had HBV genotypes B (38%) and C (60%). Antiviral response was achieved in 39% and 17% of IFN-alpha-treated patients (P =.03) and in 10% and 8% of untreated controls (P =.88) with HBV genotype B and C, respectively. Multivariate analysis identified HBV genotype B, elevated pretreatment alanine aminotransferase (ALT) levels, and low pretreatment HBV-DNA levels but not IFN-alpha treatment as independent factors associated with antiviral response. Among the 66 patients with elevated pretreatment ALT level, antiviral response was achieved in 57% and 21% of IFN-alpha-treated patients (P =.019), and in 25% and 8% of untreated controls (P =.45) with HBV genotype B and C, respectively. Multivariate analysis showed that genotype B and low pretreatment HBV-DNA levels were independent predictors of antiviral response. In conclusion, our data showed that HBV genotype B was associated with a higher rate of IFN-induced HBeAg clearance compared with genotype C. Stratification for HBV genotypes should be considered in future clinical trials of antiviral therapy of chronic hepatitis B.

Quantitative serum HBV DNA levels during different stages of chronic hepatitis B infection

The goals of this retrospective study were to determine whether there is a threshold hepatitis B virus (HBV) DNA value associated with spontaneous or antiviral therapy-related hepatitis B e antigen (HBeAg) clearance. We also investigated whether there is an HBV DNA value that can be used for differentiating inactive carriers from patients with HBeAg-negative chronic hepatitis B. HBV DNA levels in sequential serum samples of 165 Chinese patients with different stages of chronic HBV infection were quantified by a polymerase chain reaction (PCR)-based assay. Our results showed that almost all of the patients (89%) who remained HBeAg-positive had HBV DNA levels that were persistently above 10(5) copies/mL. Serum HBV DNA levels decreased by a mean of 3 log(10) in patients with HBeAg loss, but 51% had levels above 10(5) copies/mL at the time HBeAg first became undetectable. Mean serum HBV DNA levels were significantly lower in HBeAg-negative patients. HBV DNA value above 10(5) copies/mL would exclude all inactive carriers, but 45% of patients with HBeAg-negative chronic hepatitis would also be excluded if testing were only performed at presentation and 30% would be excluded if testing were performed on 3 occasions. In conclusion, serum HBV DNA levels decreased significantly in patients with HBeAg loss, but there was no threshold HBV DNA level associated with HBeAg clearance. Given the fluctuating course of HBeAg-negative chronic hepatitis, it is not possible to define a single cutoff HBV DNA value for differentiating inactive carriers from patients with HBeAg-negative chronic hepatitis.

Hepatitis B virus genotype B is associated with earlier HBeAg seroconversion compared with hepatitis B virus genotype C

BACKGROUND & AIMS

Recent studies suggest that hepatitis B virus (HBV) genotype B is associated with less active liver disease than HBV genotype C. The aim of our study was to determine if HBV genotype B is associated with higher rates of spontaneous hepatitis B e antigen (HBeAg) seroconversion compared with genotype C.

METHODS

A retrospective study using stored sera from 332 Chinese patients with chronic HBV infection followed for a mean of 48 months (range, 12-98) were tested for HBV genotype using a line-probe assay.

RESULTS

HBV DNA was detected in 273 patients, 122 had HBV genotype B and 147 genotype C. Patients with genotype B had a significantly lower prevalence of HBeAg at presentation and significantly higher rates of spontaneous HBeAg seroconversion during follow-up. HBV genotype B patients who were HBeAg positive were significantly younger, and spontaneous HBeAg seroconversion occurred approximately 1 decade earlier compared with HBV genotype C patients. Multivariate analyses identified high alanine aminotransferase (baseline and follow-up), age >30 years, and genotype B as independent factors associated with spontaneous HBeAg seroconversion.

CONCLUSIONS

HBV genotype B is associated with earlier HBeAg seroconversion than genotype C. This finding may explain the less active/progressive liver disease in patients with genotype B.

Role of chronic Helicobacter pylori infection in hyperdynamic circulation of cirrhotic patients

BACKGROUND/AIMS

Hyperdynamic circulation observed in portal hypertension is characterized by generalized vasodilatation, increased cardiac index, and increased systemic and regional blood flows, and mediated at least partly by increased nitric oxide activities. Recent studies have demonstrated that Helicobacter pylori (H. pylori) infection can stimulate nitric oxide synthase expression and activities. This study investigated if chronic H. pylori infection might be involved in the development of hyperdynamic circulation in cirrhotic patients.

METHODOLOGY

Fifty-eight patients with cirrhosis and thirty-six healthy subjects entered this study. The serologic evidence of H. pylori infection was determined with ELISA in both groups. In addition, in cirrhotic patients hemodynamic studies were performed by Swan-Ganz catheterization and thermodilution technique.

RESULTS

No significant differences in age (65.5 +/- 0.8 vs. 63.7 +/- 1.1 years), sex (male/female: 43/15 vs. 29/7) and seroprevalence of H. pylori (74.1% vs. 80.6%) were observed between cirrhotic patients and healthy subjects (P > 0.05). The seropositive rate of H. pylori in patients with cirrhosis was not associated with severity of cirrhosis and size of esophageal varices (P > 0.05). There were no significant differences in systemic vascular resistance and hepatic venous pressure gradient between cirrhotic patients with and those without chronic H. pylori infection (P > 0.05).

CONCLUSIONS

The seroprevalence of H. pylori in cirrhotic patients is similar to that of healthy controls, and not related to the severity of cirrhosis and degree of portal hypertension. Chronic H. pylori infection does not play a major role in the hyperdynamic circulation observed in cirrhotic patients.

Outcome of liver transplantation for hepatitis B: report of a single center's experience

Results of liver transplantation (LT) for hepatitis B have improved significantly with the use of hepatitis B immune globulin (HBIG) and/or lamivudine. The aim of this study is to review the long-term outcome of patients who underwent LT for hepatitis B. Records of 41 patients who underwent LT for hepatitis B and survived 3 months or longer post-LT were reviewed. Twenty patients were administered no immunoprophylaxis or short-term intramuscular HBIG, whereas 21 patients were administered high-dose intravenous (IV) HBIG. Median post-LT follow-up in these 2 groups was 76 months (range, 4 to 155 months) and 25 months (range, 4 to 68 months), respectively. Hepatitis B recurred in 15 (75%) and 4 patients (19%) who underwent LT in the pre-HBIG and post-HBIG eras, respectively. Cumulative rates of recurrent hepatitis B at 1 and 3 years post-LT in these 2 groups were 66% and 77% and 20% and 20%, respectively (P <.001). Recurrent hepatitis B in the post-HBIG era correlated with antibody to hepatitis B surface antigen titer less than 100 IU/L. Nine patients with recurrent hepatitis B were administered lamivudine for 13 to 49 months (median, 28 months); 6 patients continued to have stable or improved liver disease, whereas 3 patients developed virological breakthrough with slow deterioration of liver disease. Long-term IV HBIG is effective in preventing recurrent hepatitis B. The risk for recurrent hepatitis B is negligible after the first year post-LT. Among patients with no virological breakthrough, lamivudine can stabilize or improve liver disease for up to 4 years in patients with recurrent hepatitis B post-LT.

Molecular analysis of mucosa-associated lymphoid tissue (MALT) lymphoma of ocular adnexa

Lymphomas of mucosa-associated lymphoid tissue (MALT) are a distinct subgroup of extranodal B-cell non-Hodgkin's lymphomas. Most studies have failed to demonstrate the clonal rearrangement of BCL-1, BCL-2 or c-MYC genes for MALT lymphomas. Further, alteration of the p53 gene is rarely demonstrated in low-grade MALT lymphomas, but can be detected in high-grade disease. Lymphomas of the ocular adnexa represent approximately eight percent of all extranodal lymphomas, most of which are MALT lymphomas, but few studies had explored the alterations of BCL-1, BCL-2, c-MYC and p53 genes specifically for ocular MALT lymphomas. We investigated the changes to BCL-1, BCL-2, c-MYC and p53 genes in these lymphomas for Taiwanese patients. Clonal rearrangement for immunoglobulin heavy-chain (IgH), BCL-1, BCL-2, c-MYC and p53 genes was examined for 16 cases of ocular MALT lymphoma. Restriction-length polymorphism and polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) of the DNA, corresponding to exons 5 through 9, followed by DNA sequencing, were utilized to analyze the possible mutations of the p53 gene for these tumors. Thirteen of the cases revealed rearranged IgH genes using Southern blotting or PCR. No rearrangement of BCL-1, BCL-2, c-MYC or p53 genes was discovered, with point mutation of the p53 gene in one case. As for other types of MALT lymphomas, BCL-1, BCL-2 and c-MYC genes are not implicated in the pathogenesis of the ocular sub-group. Although alteration of the p53 gene is rare for low-grade ocular MALT lymphoma, its role in disease progression merits further research.

Hepatic encephalopathy in rats with thioacetamide-induced fulminant hepatic failure: role of endotoxin and tumor necrosis factor-alpha

BACKGROUND

Hepatic encephalopathy, a complex neuropsychiatric syndrome secondary to acute liver failure, chronic parenchymal liver disease or portal-systemic shunting, may possibly develop through mediators of endotoxin and tumor necrosis factor-alpha (TNF-alpha). However, there are no published data concerning the relationships between the severity of encephalopathy and the plasma levels of endotoxin and TNF-alpha.

METHODS

Male Sprague-Dawley rats weighing about 300-350 g were used. Fulminant hepatic failure was induced by intraperitoneal injection ofthioacetamide (350 mg/kg/day) for 3 consecutive days. Severity of encephalopathy was assessed by measuring motor counts using an Opto-Varimex animal activity meter. Plasma levels of endotoxin and TNF-alpha were determined by chromogenic Limulus assay and ELISA method, respectively.

RESULTS

Our study revealed that higher plasma levels of endotoxin (> 5.9 pg/ml) and TNF-alpha (> 18.8 pg/ml) were significantly associated with more blunted motor activities in rats with fulminant hepatic failure (p < 0.05). A significant correlation was observed between plasma concentrations of endotoxin and TNF-alpha (r = 0.59, p < 0.001). Plasma levels of endotoxin were weakly correlated with the total movements in an open field (r = -0.34, p = 0.032) and the counts of ambulatory (r = -0.38, p = 0.014) and vertical movements (r = -0.40, p = 0.010). There were no correlations between the motor counts and plasma levels of TNF-alpha (p > 0.05).

CONCLUSIONS

In addition to endotoxin and TNF-alpha, other factors may participate in the pathogenesis of hepatic encephalopathy in rats with thioacetamide-induced fulminant hepatic failure.

Endothelin-1 induces vasoconstriction on portal-systemic collaterals of portal hypertensive rats

Portal hypertension is associated with increased hepatic and collateral resistance to an increased portal blood flow. Endothelin-1 (ET-1) can induce intrahepatic vasoconstriction and consequently increase portal pressure. It is unknown if ET-1 also modulates portal pressure by a direct vasoconstrictive effect on collaterals. This study investigated the collateral vascular responses to ET-1, the receptors in mediation, and the regulation of ET-1 action by nitric oxide and prostaglandin. The portal-systemic collaterals of partially portal vein-ligated rats were tested by in situ perfusion. The concentration-response curves of collaterals to graded concentrations of ET-1 (10(-10)-10(-7) mol/L) with or without BQ-123 (ET(A) receptor antagonist, 2 x 10(-6) mol/L), BQ-788 (ET(B) receptor antagonist, 10(-7) mol/L) or both were recorded. In addition, the collateral responses to ET-1 with preincubation of n(omega)-nitro-L-arginine (NNA; 100 mol/L), indomethacin (INDO; 10 mol/L), or in combination were performed. ET-1 increased the perfusion pressure of collaterals and its effect was significantly suppressed by BQ-123 alone and BQ-123 plus BQ-788, but not BQ-788 alone (P <.05). Incubation with NNA, INDO, or both significantly enhanced the response of collaterals to ET-1 (P < .05). These results show that ET-1 produces a direct vasoconstrictive effect on the collateral vessels of portal hypertensive rats. This effect is mediated by ET(A,) but not ET(B), receptors. Both nitric oxide and prostaglandin modulate the collateral vascular response to ET-1 and may therefore participate in the development and maintenance of portal hypertension.

Detrimental effects of nitric oxide inhibition on hepatic encephalopathy in rats with thioacetamide-induced fulminant hepatic failure

Hepatic encephalopathy is a complex neuropsychiatric syndrome seen secondary to acute liver failure, chronic parenchymal liver disease, or portal-systemic anastomosis. Vasodilatation induced by nitric oxide (NO) may be involved in the development of hepatic coma. However, there are no comprehensive data concerning the effects of NO inhibition on the severity of hepatic encephalopathy. Male Sprague-Dawley rats weighing 300-350 g were used. Fulminant hepatic failure was induced by intraperitoneal injection of thioacetamide (TAA, 350 mg kg-1 day-1) for 3 days. Rats were divided into two groups to receive either NG-nitro-L-arginine methyl ester (L-NAME, 20 mg kg-1 day-1 via intragastric gavage) or normal saline (N/S) from 2 days prior to TAA administration for 5 days. Severity of encephalopathy was assessed by counts of motor activity and neurobehaviour test scores. Plasma levels of endotoxin, tumour necrosis factor-alpha and nitrate/nitrite were determined by the chromogenic Limulus assay, enzyme-linked immunosorbent assay and colorimetric assay, respectively. Compared with N/S-treated rats, the mortality rate was significantly higher in rats receiving L-NAME (59% vs. 18%, P < 0.01). Inhibition of NO had detrimental effects on the counts of motor activities (P < 0.05) and neurobehaviour score (P < 0.01). Rats treated with L-NAME had significantly higher plasma levels of endotoxin (26.7 +/- 3.8 pg mL-1) and tumour necrosis factor-alpha (29.4 +/- 6.5 pg mL-1) compared with rats treated with N/S (13.2 +/- 2.7 pg mL-1 and 11.2 +/- 2.6 pg mL-1, respectively, P < 0.01). Plasma levels of endotoxin and tumour necrosis factor-alpha, but not of nitrate/nitrite, were significantly correlated with the severity of hepatic encephalopathy (P < 0.05). Chronic L-NAME administration had detrimental effects on the severity of encephalopathy in TAA-treated rats, suggesting a protective role of NO in the development of fulminant hepatic failure.

Inhibition of prostacyclin by indomethacin ameliorates the splanchnic hyposensitivity to glypressin in haemorrhage-transfused common bile duct-ligated rats

Prostacyclin (PGI2) is an important contributor to the mediation of hyporeactivity to vasoconstrictors and the development of hyperdynamic circulation in portal hypertensive states. Inhibition of PGI2 synthesis in haemorrhage-transfused partially portal vein-ligated rats could ameliorate the splanchnic hyposensitivity to glypressin, a long-acting vasopressin analogue. This study investigated whether the hyposensitivity to glypressin also exists in rats with common bile duct ligation (BDL) and whether the inhibition of PGI2 synthesis by indomethacin could potentiate the portal-hypotensive effect of glypressin in bleeding BDL rats. Two series of BDL rats were used. Series 1 investigated the haemodynamic effects of low dose glypressin (0.07 mg kg-1) in BDL rats with or without bleeding by catheterization. In series 2, haemodynamic parameters were measured in stable or bleeding BDL rats that were receiving intravenously high dose glypressin (0.2 mg kg-1) or indomethacin (5 mg kg-1) followed by high dose glypressin. In rats with a hypotensive haemorrhage, 4.5 mL of blood was withdrawn and 50% of the withdrawn blood was reinfused before the administration of glypressin or indomethacin. Splanchnic hyposensitivity to glypressin was demonstrated in haemorrhage-transfused BDL rats receiving high, but not low, doses of glypressin. Indomethacin infusion did not cause significant systemic and portal haemodynamic changes in bleeding BDL rats (P > 0.05). The addition of indomethacin significantly enhanced the portal-hypotensive effects of glypressin (P < 0.05) and potentiated the increases in mean arterial pressure induced by glypressin infusion (P < 0.001) in bleeding BDL rats. Splanchnic hyposensitivity to glypressin observed in haemorrhage-transfused BDL rats could be ameliorated by the addition of indomethacin, suggesting a role of endogenous PGI2 in its pathophysiology.

Splanchnic hyposensitivity to glypressin in a haemorrhage/transfused rat model of portal hypertension: role of nitric oxide and bradykinin

Hyposensitivity to vasopressin is a well documented phenomenon in animals with portal hypertension and patients with cirrhosis subject to haemorrhage. Haemorrhage is associated with the endogenous release of bradykinin, which may subsequently stimulate the formation of nitric oxide (NO). The present study investigated the relative contribution of NO synthase (NOS) isoforms and the role of bradykinin in the pathogenesis of splanchnic hyposensitivity to a long-acting vasopressin analogue, glypressin, in rats with portal hypertension induced by partial portal vein ligation (PVL). At 14 days after the operation, systemic and portal haemodynamics were measured in stable or bleeding PVL rats receiving an intravenous infusion of glypressin (0.07 mg/kg). In the treatment groups, N(G)-nitro-L-arginine methyl ester (L-NAME; a non-selective NOS inhibitor), L-canavanine (a specific inhibitor of inducible NOS) or HOE 140 (a bradykinin B(2) receptor antagonist) was administered 45 min before the infusion of glypressin. In rats with a hypotensive haemorrhage, 4.5 ml of blood was withdrawn and 50% of the withdrawn blood was re-infused before the administration of glypressin or various inhibitors. Splanchnic hyposensitivity to glypressin was demonstrated in the haemorrhage/transfused PVL rats. The infusion of L-NAME elevated the mean arterial pressure in the bleeding PVL rats without the modulation of portal pressure. The addition of L-NAME or HOE 140, but not L-canavanine, significantly and similarly potentiated the portal-hypotensive effects of glypressin. It is concluded that constitutive NOS and bradykinin are responsible, at least partly, for the splanchnic hyposensitivity to glypressin observed in the early stages of the haemorrhage/transfused rat model of portal hypertension.

Chronic inhibition of nitric oxide ameliorates splanchnic hyposensitivity to glypressin in a hemorrhage-transfused rat model of portal hypertension

BACKGROUND

Vasopressin given during hemorrhage is less effective than when given during a stable state in experimental portal hypertension or patients with cirrhosis (the so-called hyposensitivity phenomenon). This study investigated whether chronic inhibition of nitric oxide (NO) synthesis by NG-nitro-L-arginine methyl ester (L-NAME), a non-selective NO synthase inhibitor, could potentiate the portal-hypotensive effect of glypressin (a long-acting vasopressin analogue) in portal-hypertensive rats during acute bleeding status.

METHODS

Portal hypertension was induced by partial portal vein ligation (PVL). Rats were divided to receive either L-NAME (approximately 25 mg/kg/day in tap water) or placebo (tap water) treatment orally from 2 days prior to until 14 days after the operation. At the end of treatment, L-NAME-and placebo-treated PVL rats were subdivided into without-bleeding and with-bleeding groups to assess the effects of glypressin (0.07 mg/kg) on systemic and portal hemodynamics. In rats with a hypotensive hemorrhage, 4.5 ml of blood was withdrawn and 50% of the withdrawn blood was reinfused before the administration of glypressin.

RESULTS

As compared with placebo-treated rats, chronic treatment with L-NAME in PVL rats significantly increased mean arterial pressure (P < 0.001) without modulating portal pressure (P > 0.05). In placebo-treated PVL rats, glypressin resulted in a less decrease in portal pressure in rats with bleeding than in those without bleeding (P < 0.05). For PVL rats with bleeding, the portal-hypotensive effect of glypressin was significantly potentiated after chronic L-NAME treatment (P < 0.05).

CONCLUSIONS

Chronic inhibition of NO alleviates the splanchnic hyposensitivity to glypressin observed in bleeding PVL rats, suggesting the pathophysiological role of nitric oxide in mediating this splanchnic hyposensitivity.

Experience-dependent structural plasticity in cortex heterotopic to focal sensorimotor cortical damage

Structural plasticity following focal neocortical damage in adult rats has recently been found to be sensitive to postinjury rehabilitative training. Experience on a complex motor skills task, the acrobatic task, after unilateral lesions of the forelimb representation region of the sensorimotor cortex (FLsmc) enhanced synaptic structural changes in the cortex contralateral and homotopic to the lesions. Using tissue from this previous study, the present study examined whether a heterotopic region of the sensorimotor cortex of either hemisphere, the hindlimb representation area (HLsmc), would undergo structural changes following unilateral FLsmc lesions and whether these changes would also be sensitive to postinjury training on the acrobatic task. Stereological methods for light and electron microscopy were used to assess structural changes in lesion or sham-operated rats following 28 days of postoperative acrobatic training or simple repetitive exercise (motor controls). In the HLsmc contralateral to the lesions of rats receiving acrobatic training, there was a subtle, but significant, increase in cortical volume and in layer II/III neuropil and dendritic volume per neuron in comparison to shams. In rats receiving simple exercise after the lesions, these changes were not significantly different from shams. Acrobatic training also prevented a loss of cortical volume in the HLsmc adjacent to the lesion in comparison to shams. These data suggest that behavioral training following cortical injury facilitates structural plasticity in behaviorally relevant areas of the neocortex other than the homotopic cortex contralateral to the lesion. This structural plasticity might be relevant to the development of behavioral compensation after cortical injury.