Genome-wide hypomethylation in hepatocellular carcinogenesis

Aberrant genome-wide hypomethylation has been thought to be related to tumorigenesis. However, its mechanism and implications in hepatocellular carcinogenesis remain to be elucidated. Samples of hepatoma (hepatocellular carcinoma, HCC) and paired non-HCC liver tissues were obtained from 17 HCC patients. Normal liver tissues obtained from three individuals were used as controls. Compared with the paired non-HCC liver tissues, genome-wide 5-methylcytosine content in HCC was reduced in all of the tested HCC samples (P < 0.001). Conversely, genome-wide 5-methylcytosine content did not significantly differ among normal, noncirrhotic, and cirrhotic liver tissues. Moreover, the degree of reduced DNA methylation was related to late histopathological HCC grade (P = 0.005) and large tumor size (P = 0.079). Compared with the paired non-HCC liver tissues, expression of DNA methyltransferases DNMT-1, DNMT-3A, and DNMT-3B and the DNA methyltransferase-like gene, DNMT-2, was up-regulated in 53, 41, 59, and 47% of the HCC samples, respectively. Surprisingly, small amounts of LINE-1 retrotransposon transcripts were detected in HCC and non-HCC as well as normal liver tissues, and the expression levels were not significantly different in HCC compared with the paired non-HCC or normal liver tissues. Of interest, the 3' ends of these LINE-1 transcripts were truncated. Our findings suggest that genome-wide hypomethylation in HCC is a continuing process that persists throughout the lifetime of the tumor cells rather than a historical event occurring in precancer stages or in cell origins for HCC. Up-regulation of DNA methyltransferases might simply be a result of increased cell proliferation in cancer. In addition, our results did not support the hypothesis of activation of transposable elements in HCC via genome-wide hypomethylation.

Surgical management for chronic pancreatitis

This study reviewed the results of surgery for chronic pancreatitis. We also attempted to identify any factors that may influence outcome. A 10-year retrospective chart review was carried out on all patients undergoing surgery for the diagnosis of chronic pancreatitis. Twenty-three patients were identified. Alcohol was the most common etiology, but other causes were identified. All but two patients had abnormal ductal anatomy on endoscopic retrograde cholangiopancreatography. A total of 23 patients underwent six different operations. There were five complications and no perioperative deaths. Only one patient had to be readmitted for pancreatitis during follow-up. The majority of patients reported some improvement with their pain. Patients who continued to use alcohol had the worst results in regard to weight gain and pain control. The results of our study are consistent with the current literature in regard to morbidity and mortality. Surgical treatment had minimal effect on endocrine and exocrine function. Weight loss was avoided in the majority of patients. Addition of biliary bypass to the Puestow procedure did not increase morbidity. Poorest results were obtained in patients who continued to use alcohol. A basic algorithm for management of this disease process is given.

Hemodynamic effects of a combination of prazosin and terlipressin in patients with viral cirrhosis

OBJECTIVES

Terlipressin reduces portal pressure in cirrhotic patients mainly through intense splanchnic vasoconstriction that decrease portal venous inflow. Hepatic blood flow may also be reduced by terlipressin. Prazosin (an alpha1-adrenoceptor antagonist) has also been proposed to decrease portal pressure in cirrhotic patients possibly through a decrease in the intrahepatic vascular resistance. The current study was aimed to evaluate whether a combination of prazosin and terlipressin exerts more beneficial effects than terlipressin alone.

METHODS

Patients were randomly assigned to receive either a placebo (n = 12) or an oral administration of prazosin 2 mg (n = 12). Thereafter, each patient received an intravenous injection of terlipressin 2 mg. Hemodynamic values were measured basally, 30 min after prazosin or placebo, and 30 min after terlipressin.

RESULTS

Placebo administration did not affect any hemodynamic values. Terlipressin administration, on the other hand, resulted in expected changes on the hepatic venous pressure gradient, hepatic blood flow, and systemic hemodynamics. In contrast, prazosin significantly decreased hepatic venous pressure gradient with an increased hepatic blood flow and intrinsic hepatic clearance. After terlipressin administration, a further decrease in hepatic venous pressure gradient was observed with preservation of hepatic blood flow and intrinsic hepatic clearance. The magnitude of decrease in hepatic venous pressure gradient was more profound in patients receiving prazosin plus terlipressin than in those receiving terlipressin alone. However, the magnitude of changes in systemic hemodynamics was no different between the two groups of patients.

CONCLUSIONS

The current study showed that a combination of prazosin and terlipressin resulted in a more profound reduction of hepatic venous pressure gradient with a preservation of hepatic blood flow and intrinsic hepatic clearance than did terlipressin alone. However, the combined therapy did not modify the systemic hemodynamic effects exerted by terlipressin.

Effects of high-cholesterol diet on the interendothelial clefts and the associated junctional complexes in rat aorta

The arterial endothelial intercellular cleft (AEC) and its associated junctional complex (JC) are the determinants of permeability to macromolecules. This study analyzed frequencies of AEC and JC profile types in the rat thoracic aorta at 1 and 12 months after feeding the animals with a normal or a high-cholesterol diet. Rats on either a normal diet or high-cholesterol diet for 12 months showed more of the simple 'end to end' or 'overlap' types (P < 0.01) but fewer complex 'interdigitating' type (P < 0.01) of AEC compared to the 1 month group. With regard to JC, the frequencies of gap junctions were decreased (P < 0.01) while the tight junctions and the normal junctionless complex were increased (P < 0.01) after 12 months of normal diet as compared with 1 month on the normal diet. These changes in frequencies for gap junction and tight junction were even greater for the high-cholesterol diet than for the normal diet treatment. Moreover, the incidence of open junctions was also noticeably increased after 12 months of high-cholesterol diet. These findings suggest that the proportions of the AEC and JC were highly responsive to aging whereas those of JC were more susceptible to the high-cholesterol diet treatment.

Characterising life-span variability in a population using the life-table-based Lorenz-curve analysis

BACKGROUND

'Life expectancy' (LE) is a health-status indicator in widespread use. However, LE is an index of central location, but not of dispersion. It cannot describe inter-individual variation in the life-span. This author proposes using the Gini coefficient, a summary index of the Lorenz curve, for characterising life-span variability. Like the LE, the proposed index is also based on a lifetable.

METHOD

The method is a nonparametric approach that does not make specific assumptions about mortality rates.

RESULTS

The author uses vital statistics from Taiwan as a demonstration and finds that the method provides information crucial to the understanding of the epidemiologic transitions of the past 20 years (Gini decreases from 0.1320 to 0.1130). It also quantifies the impacts of elimination of some selected causes of death in Taiwan.

CONCLUSIONS

It is recommended that Gini be routinely compiled in official vital statistics, along with the LE.

Portopulmonary hypertension: distinctive hemodynamic and clinical manifestations

Portopulmonary hypertension is now recognized as one of the pulmonary complications of chronic liver disease. However, previous studies reported that the incidence ranged from 0.25% to 2%, excluding fortuitous coincidence. In this study, we aimed to determine the variant hemodynamic and clinical features of portopulmonary hypertension in an area with a high prevalence of viral cirrhosis. After reviewing the hemodynamic data of 322 patients with portal hypertension admitted to the Taipei Veterans General Hospital between 1987 and 1999, we found 10 with portopulmonary hypertension. The overall incidence was, therefore, 3.1% in all patients with portal hypertension. Most of the patients with portopulmonary hypertension experienced exertional dyspnea. The survival times ranged from 2 to 86 months. In our series, most of the patients who died, died of complications related to cirrhosis and portal hypertension, but not of complications related to pulmonary hypertension. This study suggested that portopulmonary hypertension was not a frequent complication in cirrhotic patients and was not associated with an adverse outcome.

Structure and site-directed mutagenesis of a flavoprotein from Escherichia coli that reduces nitrocompounds: alteration of pyridine nucleotide binding by a single amino acid substitution

The crystal structure of a major oxygen-insensitive nitroreductase (NfsA) from Escherichia coli has been solved by the molecular replacement method at 1.7-A resolution. This enzyme is a homodimeric flavoprotein with one FMN cofactor per monomer and catalyzes reduction of nitrocompounds using NADPH. The structure exhibits an alpha + beta-fold, and is comprised of a central domain and an excursion domain. The overall structure of NfsA is similar to the NADPH-dependent flavin reductase of Vibrio harveyi, despite definite difference in the spatial arrangement of residues around the putative substrate-binding site. On the basis of the crystal structure of NfsA and its alignment with the V. harveyi flavin reductase and the NADPH-dependent nitro/flavin reductase of Bacillus subtilis, residues Arg(203) and Arg(208) of the loop region between helices I and J in the vicinity of the catalytic center FMN is predicted as a determinant for NADPH binding. The R203A mutant results in a 33-fold increase in the K(m) value for NADPH indicating that the side chain of Arg(203) plays a key role in binding NADPH possibly to interact with the 2'-phosphate group.

Molecular structure, dynamic expression, and promoter analysis of zebrafish (Danio rerio) myf-5 gene

We isolated a 1,438 bp cDNA fragment that encoded Myf-5 myogenic factor of zebrafish. The deduced amino acid contained 237 residues, including the basic helix-loop-helix domain that is conserved in all known Myf-5. The zebrafish myf-5 transcripts were first detectable at 7.5 hpf, increased substantially until 16 hpf, and then declined gradually to an undetectable level by 26 hpf. During somitogenesis, zebrafish myf-5 transcripts were distributed mainly in the somites and segmental plates. Prominent signals occurred transiently in adaxial cells in two parallel rows but did not extend beyond the positive-signal somites. Various lengths of upstream region of zebrafish myf-5 fused with EGFP gene were used to carry out transgenic analysis. Results showed that a small, 82 bp (nucleotide positions from -82 to -1), regulatory cassette is sufficient to control the somite- and stage-specific expression of zebrafish myf-5 during early development.

Mirizzi's syndrome: experience from a multi-institutional review

P.L. Mirizzi described in 1948 a partial or spastic obstruction of the common hepatic duct secondary to an impacted gallstone in the cystic duct or infundibulum of the gallbladder. The modern definition of Mirizzi's syndrome is thought to include four components: anatomic arrangement of the cystic duct at the gallbladder neck such that it runs parallel to the common hepatic duct; impaction of a stone in the cystic duct or neck of the gallbladder; mechanical obstruction of the common hepatic duct by the stone itself or by secondary inflammation; and intermittent or constant jaundice causing possible recurrent cholangitis and, if longstanding, secondary biliary cirrhosis. Intermittent symptomatology may make Mirizzi's syndrome difficult to diagnose preoperatively or intraoperatively. Bilio-biliary fistulas may or may not be present. Diagnosis and choice of operative repair may be best accomplished by open operative technique. Over a 24-year period two faculty members from Louisiana State University (LSU) Medical Center-Shreveport at Monroe and LSU Baton Rouge treated 4180 cases of cholelithiasis at six Louisiana university and private hospitals. Eleven cases of Mirizzi's syndrome were diagnosed on the basis of operative and preoperative notes with detailed description of size and extent of biliobiliary fistulas when they were present. These 11 cases were reviewed and followed from one to 20 years. Presentation, workup, operative findings, choice of operative repair, choice of operative approach, and complications were evaluated by retrospective chart review. Review of the pertinent literature for informative and comparative purposes was also completed. These 11 cases ranged from Csendes Type I to III. There were no Type IV cases. They were ultimately diagnosed and managed by classical open technique. Four laparoscopic procedures were converted to open technique following initial inspection. All four were converted to open as a result of inability to delineate structures in and adjacent to the triangle of Calot due to marked scarring in the subhepatic space. No iatrogenic injuries or major complications occurred. Mirizzi's syndrome occurs in fewer than 0.5 per cent of patients with cholelithiasis. Removal of stones with partial cholecystectomy and use of gallbladder or cystic duct remnant to oversew or repair Mirizzi fistulas should be considered. Roux-en-y hepaticojejunostomy becomes the procedure of choice when the vascularity or viability of the hepatic duct or tissues available for duct repair is questionable. Review of the literature reveals the increase in complications with laparoscopic versus open technique in Mirizzi's syndrome. Although very little direct evidence exists we believe that when this syndrome is diagnosed or strongly suspected open biliary operation is the procedure of choice because the increased potential for major complications with the use of laparoscopic technique far outweighs the potential slight increase in morbidity of an open procedure.

Molecular cloning and expression analysis of human glycogen synthase kinase-3 alpha promoter

Human glycogen synthase kinase-3 alpha (GSK-3 alpha) is a serine/threonine kinase that phosphorylates a variety of cytoplasmic and nuclear proteins. It also phosphorylates components of the neuronal cytoskeleton including tau and neurofilament heavy chain. Hyperphosphorylated tau is found in neurofibrillary tangles, a hallmark of Alzheimer's disease and aberrant phosphorylation of neurofilament heavy chain is observed in motor neuron disease. Alterations in GSK-3 alpha activity may therefore contribute to the disease process in these disorders. As a first step to understand the transcriptional regulation of GSK-3 alpha, a 2-kb (p-1751/+243) DNA fragment upstream of the GSK-3 alpha initiation codon was obtained from a YAC clone and characterised. Using primer extension assays, a putative transcriptional start site was located to a G nucleotide 244 bp upstream of the ATG codon. Several transcription factor-binding sites were identified on the promoter region, but no TATA-like element was located close to the start site. Deletion mutants of the 2-kb DNA fragment were generated and fused to a promoterless chloramphenicol acetyltransferase (CAT) gene. Transfection study in a neuroblastoma cell line revealed the 1-kb (p-719/+243) fragment carried strong promoter activity, while the 2-kb construct that contains an Alu-like sequence was only 50% active.

Association of heat shock protein 70 with semen quality in boars

This study attempted to clarify the relationship between the levels of 70kDa heat shock protein (HSP70) and semen quality in boars. Semen samples from 29 (13 Duroc, 9 Landrace, and 7 Yorkshire) boars (mean age=25.2+/-2.2 months) were examined. Three to four ejaculates per boar, collected during cool and hot seasons, were evaluated in terms of the sperm concentration, sperm motility, percentage of normal and abnormal sperm, as well as percentage of sperm with proximal and distal plasma droplets. Significant seasonal and breed differences in semen quality were observed. Experimental results indicate that the semen quality of Landrace boars was better than those of Yorkshire and Duroc boars (P<0.05) and semen quality declined significantly during the hot season (P<0.05). One-dimensional SDS-PAGE analysis of spermatozoa proteins indicated that protein profiles did not significantly differ between seasons and among breeds. Both constitutive and stress-inducible form of HSP70 were detected in boar spermatozoa by Western blot analysis. The level of HSP70, which revealed no difference among breeds within a season, was significantly lower during the hot season in all the three breeds (P<0.05). Although there appeared to be low correlation coefficients between the level of HSP70 and semen quality traits, the semen quality tended to decline significantly in samples with a lower level of HSP70. Results in this study suggest that the levels of HSP70 in boar spermatozoa are significantly lower during the hot season and might be associated with semen quality.

Synthesis of 60- and 72 kDa heat shock proteins in early porcine embryogenesis

Proteins of selected embryonic stages were metabolically labeled with [(35)S]-methionine and analyzed by two-dimensional SDS-polyacrylamide gel electrophoresis (2-D PAGE) to study protein expression from 4- to 8-cell to blastocyst stage of porcine embryos. Two proteins with molecular weights of 60 and 72kDa were de novo synthesized during the 4- to 8-cell stage were the earliest that were detected. They were identified as HSP60 and HSP72 according to their locations on 2-D autoradiography and the immunoblotting result of anti-HSP 60 and HSP 72 antibodies of 1-cell stage of porcine embryos. In protein translation in early pig embryogenesis the timing of their synthesis suggests that HSP60 and HSP72 play significant roles as chaperones.