Gain of chromosomes 15 and 19 is frequent in both mouse hepatocellular carcinoma cell lines and primary tumors, but loss of chromosomes 4 and 12 is detected only in the cell lines

Chromosomal alterations were investigated in hepatocellular carcinoma cell lines, primary tumors and liver epithelial cell lines derived from normal livers of C57BL/6JxC3H/HeJ F(1) and C3H/HeJxC57BL/6J F(1) mice. In the primary tumors, non-random gain of chromosomes 15 and 19 was found in seven and five of 14 hepatocellular carcinomas, respectively. On the other hand, in the cases of both liver epithelial and hepatocellular carcinoma cell lines, frequent changes were loss of chromosomes 4 (4/9 cell lines) and 12 (3/9) as well as gain of chromosomes 15 (5/9) and 19 (4/9). These results indicate that the chromosomal gain is associated with both in vivo carcinogenesis and establishment of cell lines, while the loss is specific for the latter. PCR analysis using polymorphic microsatellite DNA markers revealed that the loss of chromosome 12 as well as chromosome 4 was much more frequent for the C57BL/6J hepatocarcinogenesis-resistant rather than the susceptible C3H/HeJ strain.

Intrathecal co-administration of NMDA antagonist and NK-1 antagonist reduces MAC of isoflurane in rats

BACKGROUND

Intravenous administration of N-methyl-D-aspartate (NMDA) receptor antagonists and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor antagonists reportedly reduce the minimum alveolar anaesthetic concentration (MAC) for inhalation anaesthetics. If pain perception can be prevented by the intrathecal administration of antinociceptive receptor antagonists, these agents may reduce the requirements for inhalation anaesthetics. We studied the effect of intrathecal administration of an AMPA/kainate receptor antagonist, a metabotropic glutamate (mGlu) receptor antagonist and co-administration of NMDA and a neurokinin-1(NK-1) receptor antagonist drugs at low doses on the MAC.

METHODS

After Wistar rats (n=36) were fitted with indwelling intrathecal catheters, the MAC of isoflurane was determined following intrathecal administration of a non-NMDA receptor antagonist (CNQX) at 10 microg, a mGlu receptor antagonist (AP3) at 10 microg, or a combination of NMDA receptor antagonist (APV) at 0.01 microg to 1 microg with NK-1 receptor antagonist (CP96345, CP) at 0.1 microg to 10 microg. Subsequently, a reversal dose of intrathecal NMDA with substance P (SP) was administered, and the MAC of isoflurane was redetermined. Conscious rats (n=15) were also examined for the presence of locomotor dysfunction following the intrathecal co-administration of APV and CP.

RESULTS

Neither CNQX nor AP3 reduced the MAC of isoflurane. APV at 0.01 microg plus CP at 1 microg, as well as APV at 0.1 microg plus CP at 10 microg, reduced the MAC of isoflurane, with respective reductions of 7.6% and 14%; (P<0.05). Co-administration of NMDA plus SP reversed the decrease in the MAC of isoflurane. Locomotive activity was not changed.

CONCLUSIONS

The NMDA receptor and the NK-1 receptor are important determinants of the MAC of isoflurane, exerting this influence by inhibition of pain transmission in the spinal cord, while mGlu and AMPA receptors have no effect on the MAC of isoflurane.

Effects of summer camp endurance training on non-specific immunity in long-distance runners

The present study was conducted to investigate the effects of endurance training during a 1-month summer camp on the non-specific host defence systems of ten highly trained male long-distance runners. Examinations with informed consent were carried out three times: 2 days before the training began, an intermediate day, and 2 days after the camp. The subjects ran a total of about 800 km during the camp. Neutrophilic reactive oxygen species (ROS) generation determined by luminol- and lucigenin-dependent chemiluminescence and cytochrome c reduction methods was assayed at two time points because the camp was held far from our laboratory: neutrophils isolated 6 hours after blood sampling were examined at all three time points and neutrophils isolated immediately after blood sampling were examined before and after the camp. The ROS production indicated by peak height of luminol-dependent chemiluminescence and peak velocity of cytochrome c reduction from neutrophils isolated 6 hours after blood sampling was suppressed after the camp (P < 0.05 for both), but, the ROS production from neutrophils isolated immediately after blood sampling and the serum opsonic activity appeared not to be affected. Neutrophils diminished their activity during the 6-hour waiting time after the camp. These results suggest that the non-specific host defence system is not directly impaired by long, strenuous endurance training.

Lymph node metastasis is associated with allelic loss on chromosome 13q12-13 in esophageal squamous cell carcinoma

Allelotype analysis of whole chromosomes showed that loss of heterozygosity (LOH) on 13q was exclusively associated with lymph node metastasis and poor prognosis in esophageal squamous cell carcinoma (ESC). To identify a locus responsible for lymph node metastasis, we performed fine deletion mapping on 13q by analyzing 60 ESCs with 18 polymorphic markers. Allelic loss was observed with at least one marker in 34 tumors (56.7%), and lymph node metastasis was significantly correlated with LOH (P = 0.0053). We found frequent loss at D13S260 (43.7%), D13S171 (38.6%), and D13S267 (43.6%) on 13q12-13. Among these markers, LOH at D13S171 showed a significant correlation with lymph node metastasis (P = 0.0441). Because these markers flank the BRCA2 gene, we intensively examined a mutation of the gene through all coding exons and exon-intron junctions by PCR-single-strand conformational polymorphism analysis under two different assays. We found only seven nucleotide substitutions as normal polymorphic changes; tumor-specific mutations were not detected, and loss of expression was not observed, indicating that the BRCA2 gene might not be a target of allelic loss in this region. Relatively frequent LOH was also found at the RB1 locus (34.7%), but a significant correlation with lymph node metastasis was not observed (P = 0.7430). Protein expression of RB1 was examined in 31 ESC cell lines, and loss of expression was infrequent (6.5%), indicating that inactivation of the RB1 gene might not be responsible for lymph node metastasis. Taken together, allelic loss at 13q12-13 of the primary ESC was closely associated with lymph node metastasis, and unidentified tumor suppressor gene(s) in this region might be involved.

Identification of a member of the serralysin family isolated from a psychrotrophic bacterium, Pseudomonas fluorescens 114

An extracellular metalloprotease named No. 114 protease is one of the major secretions of a psychrotrophic bacterium, Pseudomonas fluorescens 114, the cold-adaptation mechanism of which has not been identified. In this study, we purified and cloned No. 114 protease, which is a single polypeptide having a molecular mass of 47 kDa. This protease contains a zinc-binding motif (HEXXHXUGUXH: X, arbitrary amino acid; U, bulky hydrophobic amino acid), glycine-rich repeats (GGXGXD) and no cysteine residue, which are the features specifically found in serralysin subfamily. No. 114 protease has its maximum activity at the temperature of 35-40 degrees C, which is about 20 degrees C lower than that of a serralysin from a mesophilic bacterium, Pseudomonas aeruginosa. All these results imply that No. 114 protease from this psychrophilic bacterium is a unique member of the serralysin group characterized by a low optimal temperature.

A genetic effect of altered gravity: mutations induced by simulated hypogravity and hypergravity in microsatellite sequences of human tumor cells

To determine the possible genetic effects of gravity alterations, we analyzed mutation induction in microsatellite sequences of human tumor cells treated with simulated hypogravity provided by a clinostat or hypergravity by a centrifuge. Microsatellite mutations were detected as changes in the size of polymerase chain reaction (PCR)-amplified allelic markers. The frequencies of mutant clones in cultures treated with simulated hypogravity for 24 or 48 h were almost the same as those of controls, but after 72 h of treatment, the mutant frequencies had increased significantly in all three microsatellite loci examined. Significantly higher mutant frequencies were similarly detected in cultures treated for 72 h with a hypergravity condition as low as 18xg, but not detected in 24 or 48 h treated cultures. These findings clearly show that gravity alterations that last for 3 days can induce microsatellite mutations in human cells. A genetic effect of gravity change, therefore, is established for the first time. Moreover, high frequencies of microsatellite mutations were induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) which activates protein kinase C-mediated signal transduction pathways and causes genetic instability. These findings suggest that gravity change induces microsatellite mutations by modulating the pattern of gene expression involved in signal transduction pathways.

Beta-catenin mutations are frequent in hepatocellular carcinomas but absent in adenomas induced by diethylnitrosamine in B6C3F1 mice

Activating mutations in the region of the beta-catenin gene corresponding to the NH2-terminal phosphorylation sites of glycogen synthetase kinase 3beta have been causally implicated in carcinogenesis. In this study, the beta-catenin exon 3 was examined in hepatic lesions induced by diethylnitrosamine in B6C3F1 mice. PCR and DNA sequencing detected seven beta-catenin mutations in 13 samples dissected from hepatocellular carcinoma tissues, but none in 14 hepatic adenomas. All of the mutations were found in codon 41 encoding a threonine residue, one of the possible glycogen synthetase kinase-3beta phosphorylation sites. Although beta-catenin protein was immunohistochemically stained mainly on the cell membrane in preneoplastic hepatocytic foci and most adenomas, as observed in normal hepatocytes, it was detected in the cytoplasm and nuclei in addition to the cell membrane, indicating stabilization of the protein in HCCs. This shift in staining was observed not only in tumors with mutations, but also in examples lacking exon 3 mutations. Our data demonstrate that beta-catenin alterations may be important for malignant progression during multistep hepatic carcinogenesis in mice.

The effect of intrathecal magnesium sulphate on nociception in rat acute pain models

We examined the antinociceptive effect of intrathecally administered magnesium sulphate (MgSO4) in rats, using acute pain models including mechanical pressure, heat and subcutaneous formalin injection. According to the locomotion test 10 microliters of 6.2% MgSO4 did not produce motor paralysis. At the same dose, responses to pressure and heat were intact, compared with controls given saline. MgSO4 produced depression of pain responses only after the first 10 min in the formalin test. Our studies indicated that MgSO4 did not show remarkable antinociceptive effects in acute pain models.

Hyperventilation after tourniquet deflation prevents an increase in cerebral blood flow velocity

PURPOSE

In this study we examined whether normocapnia maintained by hyperventilation after lower limb tourniquet deflation prevents an increase in cerebral blood flow velocity.

METHODS

Thirteen patients, undergoing elective orthopedic surgery, requiring a pneumatic tourniquet around the lower extremity, were divided into two groups. In group 1, ventilation was controlled at tidal volume of 10 mL x kg(-1) and respiratory rate of eight per minute after tourniquet release. In group 2, ventilation was controlled to maintain P(ET)CO2 between 30 and 35 mmHg after tourniquet release. Arterial blood pressure, heart rate, peak and mean middle cerebral artery (MCA) flow velocity, and arterial blood gas were measured every minute for ten minutes after tourniquet release. The MCA blood flow velocity was measured using Transcranial Doppler ultrasonography (TCD).

RESULTS

In group 1, the maximum peak MCA flow velocity was 53+/-6 cm x sec(-1) (50%+/-6% increase compared with pre- release value), and achieved 3+/-0.4 min after tourniquet release. In group 2, there was no increase either in mean or peak MCA velocity after tourniquet release.

CONCLUSIONS

Normocapnia maintained by hyperventilation after tourniquet deflation prevents an increase in cerebral blood flow velocity.

Characterization of six cell lines established from human pancreatic adenocarcinomas

BACKGROUND

Six human pancreatic carcinoma cell lines, designated as KMP-1 to KMP-6, were established and maintained in vitro for > 3 years. All were derived from pancreatic ductal adenocarcinomas. The six cell lines originated from either primary pancreatic tumors, metastatic liver tumors, or metastases to lymph nodes.

METHODS

Each cell line was characterized by its morphology, doubling time, colony forming efficiency (CFE) on plastic dishes, tumorigenicity in nude mice, chromosomal analysis, and the amount of tumor markers secreted into the culture medium. Furthermore, mutations in the K-ras, p53, and p16/INK4a genes were analyzed.

RESULTS

All cell lines grew as an adhering monolayer and were cultured in medium supplemented with 2% fetal bovine serum. The doubling time ranged from 16-70 hours, and the CFE ranged from 0.1-11%. Subcutaneous transplantation of these carcinoma cells into nude mice resulted in the formation of tumors. Chromosomal analysis showed that the modal numbers ranged from 43-124, and each karyotype was unique. Each cell line secreted detectable amounts of squamous cell carcinoma antigen, carcinoembryonic antigen, carbohydrate antigen 19-9, Dupan-II, and cytokeratin 19 fragment, respectively. Genetic alterations of the K-ras, p53, and p16 genes were detected in six, three, and five, respectively, of the six cell lines.

CONCLUSIONS

The authors believe that these newly established pancreatic carcinoma cell lines will contribute to wide ranging studies regarding pancreatic carcinoma progression.

The choleretic effects of N-acetylglucosaminides, major urinary metabolites of ursodeoxycholic acid, in bile fistula rats

We investigated the effects of three bile acids conjugated with N-acetylglucosamine, ursodeoxycholate N-acetylglucosaminide, tauroursodeoxycholate N-acetylglucosaminide and glycoursodeoxycholate N-acetylglucosaminide, on bile flow and biliary excretion of various markers in comparison with ursodeoxycholic acid, tauroursodeoxycholic acid and glycoursodeoxycholic acid in bile fistula rats. These bile acids were infused intravenously at a constant rate of 0.3 or 0.6 micromol/min/100 g b.w. for 2 h. All bile acids examined increased bile flow in a dose-dependent manner. In particular, ursodeoxycholate N-acetylglucosaminide has a longer-lasting effect after its infusion on bile flow than the other bile acids. Furthermore, these bile acids markedly increased biliary total bile acid excretion. At a higher dose level, the coefficient of determination (r2) between the biliary total bile acid excretion and bile flow for ursodeoxycholate N-acetylglucosaminide (r2 = 0.39) was lower than that for the other bile acids (r2 = 0.75-0.92). The ursodeoxycholate N-acetylglucosaminide, as well as tauroursodeoxycholic acid, glycoursodeoxycholic acid, tauroursodeoxycholate N-acetylglucosaminide and glycoursodeoxycholate N-acetylglucosaminide, was mostly excreted in an unchanged form in bile, whereas ursodeoxycholic acid was excreted as a conjugate with taurine. The three N-acetylglucosaminides as well as ursodeoxycholic acid, tauroursodeoxycholic acid and glycoursodeoxycholic acid significantly increased the biliary excretion of cholesterol, phospholipid, bilirubin and total Ca2+. In contrast, the N-acetylglucosaminides significantly decreased in biliary bicarbonate concentration, whereas ursodeoxycholic acid significantly increased biliary bicarbonate concentration. However, tauroursodeoxycholic acid and glycoursodeoxycholic acid did not significantly change the biliary bicarbonate concentration. The results indicate that N-acetylglucosaminides have a choleretic effect in bile fistula rats. Our present study also demonstrates that N-acetylglucosaminides, but not ursodeoxycholic acid, tauroursodeoxycholic acid or glycoursodeoxycholic acid, can significantly reduce the biliary bicarbonate concentration. Furthermore, our findings suggest that ursodeoxycholate N-acetylglucosaminide may partly exert a choleretic effect via mechanisms different from those of the other bile acids.

The effects of static magnetic fields and X-rays on instability of microsatellite repetitive sequences

To determine the genetic effect of static magnetic fields (SMF), which are not supposed to produce any significant DNA damage, we took advantage of DNA mismatch repair (MMR) deficient cells, in which all the errors produced during DNA replication are left uncorrected. We first established a simple and less labor-intensive method to analyze genetic changes in microsatellite repetitive sequences in the MMR-deficient cells. After exposure to a strong SMF (6.34T) for 24 h, both MMR deficient HCT116 cells and proficient HeLa S3 cells did not exhibit any significant effect on microsatellite changes. Moreover, when HCT116 cells were synchronized at the G1/S boundary by aphidicolin and exposed to SMF during the whole S-phase, no increase in microsatellite changes was either observed. In contrast, irradiation by a low dose X-ray (2Gy) significantly increased microsatellite changes in HCT116 cells. This suggested that exposure to strong SMF may not induce any significant level of genetic changes in microsatellite sequences.

Simultaneous determination of bile acids in rat liver tissue by high-performance liquid chromatography

A method for the simultaneous determination of bile acids in rat liver tissue by high-performance liquid chromatography was developed. Without prior fractionation and alkaline hydrolysis, 30 unconjugated, glycine- and taurine-conjugated bile acids were detected by post-column enzymatic reaction and fluorescence detection. They were separated on a reversed-phase column using a linear gradient solvent system of 10 mM tribasic ammonium phosphate-acetonitrile-methanol (44:12:5, v/v/v) and 20 mM dibasic ammonium phosphate-acetonitrile-methanol (2:1:2, v/v/v). The limits of detection were 1-5 pmol, and calibration curves were linear for concentrations ranging between 10 and 4000 pmol per 10 microl injection. This rapid and reliable method is effective for measuring bile acid levels in liver tissue not only of rats but also of patients with hepatobiliary and other diseases.

The effect of intrathecal administration of magnesium sulphate in rats

Somatosensory evoked potential, locomotion and vocalisation upon tail pinch in rats was studied in order to determine whether intrathecal magnesium sulphate administration causes spinal anaesthesia. In Wistar rats with indwelling intrathecal catheters, cortical somatosensory evoked potential was recorded following stimulation via electrodes inserted into the hind paw under chloral hydrate anaesthesia before and after intrathecal administration of 10 microliters of either magnesium sulphate (12.3% or 24.6%) or lignocaine (4% or 8%). Locomotion and vocalisation after tail pinch were tested following intrathecal administration of the same two drugs in conscious rats. Somatosensory evoked potential amplitude was diminished after administration of lignocaine (p < 0.05) but did not change after magnesium sulphate. Latency of P1 was increased by lignocaine and by magnesium sulphate 12.3% (p < 0.05). Although lower extremity paralysis was observed in both groups, its duration with magnesium sulphate was much longer than with lignocaine. Vocalisation was recognised after magnesium sulphate 12.3%, but was not observed after lignocaine 8% during paralysis (p < 0.05). We believe that magnesium sulphate caused motor paralysis, but not complete analgesia.

Methylation of the 5' CpG island of the FHIT gene is closely associated with transcriptional inactivation in esophageal squamous cell carcinomas

Previous studies suggested that the FHIT (fragile histidine triad) gene on 3p14.2 might be involved in the development of esophageal squamous cell carcinomas, but the mechanisms for inactivating the gene have not been fully revealed. In the present study, we examined aberrations of the FHIT gene in 23 esophageal squamous cell carcinoma cell lines and 35 primary tumors. We detected aberrant expression in seven cell lines (30%), including a shorter transcript in two cell lines and loss of apparent transcript in five cell lines. Genomic PCR or cDNA sequencing analysis revealed a single exon deletion in two cell lines with a shorter transcript and one cell line without expression, but no structural alterations were found in the other 20 cell lines, including transcriptionally repressed four cell lines. Next we examined methylation of the 5' CpG island of the FHIT gene by bisulfite genomic sequencing. Hypermethylation of the 5' CpG island of the FHIT gene was observed in three of four structurally unaltered but transcriptionally repressed cell lines. The remaining cell line harbored a point mutation upstream of exon 1. All methylated cell lines exhibit re-expression of the FHIT gene and demethylation in the CpG island after treatment with demethylating agent 5-aza-2'-deoxycytidine. Hypermethylation was also found in 5 of 35 (14%) primary tumors, whereas corresponding normal tissue shows no methylation. These findings suggest that methylation of the 5' CpG island of the FHIT gene is closely associated with transcriptional inactivation and might be involved in tumor development of the esophagus.

Regulation of CYP1A and CYP3A mRNAs by ascorbic acid in guinea pigs

In previous studies, we found that the ascorbic acid (AsA) deficiency caused changes in the amounts of the various forms of cytochrome P450 (P450) in liver microsomes from guinea pigs in a form-specific manner. Thus, the aim of this study was to clarify whether the changes seen in the protein contents of the various forms of P450 were associated with the levels of the expression of their mRNAs. Prior to determining the mRNA level, we isolated four cDNA clones, encoding CYP1A2, CYP3A14, CYP3A15, and CYP3A17, from guinea pig liver cDNA libraries to use them as probes in further experiments. The amino acid sequence of the guinea pig CYP1A2 showed identity ranging from 73 to 77% with those of other mammalian P450s. The amino acid sequences among guinea pig CYP3As had about 94% identities with each other. The AsA deficiency apparently decreased the expression of mRNA for CYP1A1 and CYP1A2. These results were in agreement with the decrease in the content of CYP1A1 and CYP1A2 proteins. The amount of P450 protein(s) immunochemically cross-reactive with antibodies to human CYP3A4 was likely unaffected while that of human CYP3A7 tended to be decreased by the AsA deficiency. It suggested that the expression of each CYP3A isozyme was regulated differently by AsA. In fact, the level of mRNA for CYP3A14 was unaffected by the AsA deficiency, while those for CYP3A15 and CYP3A17 were significantly decreased by the AsA deficiency, clearly indicating that the expression of each isozyme within the CYP3A subfamily is differently regulated by AsA. These results support the idea that the transcription of P450 is regulated by AsA in guinea pigs.

Mutations induced in Drosophila during space flight

To examine the possible effects of space radiation on living organisms, fruit flies Drosophila melanogaster were loaded on the US Space Shuttle Endeavour, and after the flight we have analyzed two types of mutations, sex-linked recessive lethal mutations induced in male reproductive cells and somatic mutations which give rise to morphological changes in hairs growing on the surface of wing epidermal cells. Wild type strains and a radiation-sensitive strain mei-41 were used. The frequencies of sex-linked recessive lethal mutations in flight groups were 2 and 3 times higher for wild type Canton-S and mei-41 strains, respectively, than those in ground control groups. By contrast, the frequencies of wing-hair somatic mutations differed little between flight and control groups. The possibility that the space environment causes mutations in certain types of cells such as male reproductive cells, is discussed.

Alteration of cell cycle-related genes in hepatocarcinogenesis

The mammalian cell cycle is controlled by regulators of the G1 to S transition such as tumor suppressor proteins, p53 and retinoblastoma (RB); cyclin D1 and cyclin-dependent kinase 4; and inhibitor of cyclin dependent kinase, p16INK4A. Recently, aberrations of these cell cycle-related genes have been reported to contribute to the formation and development of cancer. In human hepatocellular carcinoma (HCC), high frequencies of aberration have been detected in the p53 and RB genes. Loss of heterozygosity (LOH) of chromosome 13q was detected in 35% of HCC and LOH on chromosome 17p was detected in 49%. Mutation of the p53 gene was also detected in 32%. The aberrations of these genes were observed more frequently in poorly differentiated and in advanced HCCs. On the other hand, genetic alterations of the cyclin D1 and p16INK4A genes were not so frequent, but appeared to be associated with the aggressive behavior of the tumor, which suggests that disruption of the cell cycle-related genes results in the progression of HCC. Further study with a substantial number of cases is required to determine the actual frequency of the aberrations of the G1 controlling genes in hepatocarcinogenesis.

Hypermethylation in the retinoblastoma gene is associated with unilateral, sporadic retinoblastoma

We previously reported 9 unilateral, sporadic retinoblastomas with hypermethylation in the 5' region of the RB gene, and we found that CpG methylation in the RB promoter inhibits the binding of the retinoblastoma binding factor 1 (RBF-1) and the activating transcription factor (ATF)-like factors, thereby resulting in a considerable reduction in RB promoter activity. In this study, we screened for hypermethylation in 121 additional cases of retinoblastoma, and found 5 tumors with hypermethylation, including 4 unilateral, sporadic tumors, and one hereditary tumor. The hereditary tumor had a germline deletion of one allele, and the hypermethylation was an acquired, epigenetic change in the other allele. Another tumor had hypermethylation restricted to approximately 800 base pairs in the RB promoter region including the essential RBF-1 and ATF sites. The frequency of hypermethylation in unilateral, sporadic tumors was 9.3% combining our previous and present examinations (13 among 140), whereas the frequency was 1.0% in bilateral hereditary tumors (one among 101). The statistical analyses using the chi-square test indicated significant correlation between hypermethylation and unilateral, sporadic tumors (p < 0.05). These results suggest that hypermethylation in the RB gene is always an acquired, epigenetic change and causes about 9% of unilateral, sporadic tumors.

Improvement of estradiol-17 beta-D-glucuronide-induced cholestasis by sodium tauroursodeoxycholate therapy in rats

BACKGROUND

Estradiol-17 beta-D-glucuronide (E-17G), a metabolite of natural estrogen, is well known to cause intrahepatic cholestasis in humans. We therefore investigated the effect of sodium tauroursodeoxycholate (T-UDCA), on E-17G-induced cholestasis in female rats.

METHODS

For the evaluation of the drug, animals given E-17G (10 mumol/kg) were divided into three groups, and T-UDCA was administered intravenously at various doses after E-17G treatment.

RESULTS

T-UDCA significantly prevented a marked reduction of bile flow in E-17G-treated rats in all experimental schedules. Furthermore, T-UDCA significantly increased in the biliary E-17G excretion rate at an early stage after E-17G treatment in rats. However, this drug caused no significant change in the biliary excretion rate of estradiol-3-sulfate-17 beta-D-glucuronide (E-3S-17G), which is identified as the major biliary metabolite with E-17G throughout the recovery periods.

CONCLUSION

These results suggest that T-UDCA can improve E-17G induced acute cholestasis by rapidly increasing the biliary E-17G excretion rate. Thus our finding may provide a useful approach for attempts to prevent drug-induced acute cholestasis in humans.

Effect of sodium tauroursodeoxycholate (UR-906) on liver dysfunction in bile duct-ligated rats

We investigated the effect of sodium tauroursodeoxycholate (UR-906) on cholestasis in common bile duct-ligated rats in comparison with the effect of dehydrocholic acid. UR-906 (30-180 mumol/kg) and dehydrocholic acid (180 mumol/kg) were intravenously given once daily for consecutive 20 days in rats and the common bile duct was ligated for the last 10 days. On the next day after the last test drug administration, serum biochemical and plasma hemostatic variables were determined. UR-906 significantly ameliorated the elevation of serum cholesterol, phospholipid, bilirubin and bile acid concentrations in bile duct-ligated rats. UR-906 significantly suppressed the prolongation of plasma prothrombin time and activated partial thromboplastin time. Furthermore, UR-906 significantly suppressed the decreases in plasma coagulation factor II and X activities. However, dehydrocholic acid did not cause significant changes in any of the variables examined in this model. These results suggest that UR-906 has a beneficial effect against cholestasis induced by bile duct ligation in rats and that this drug may be useful in the treatment of clinical cholestatic disorders.

Genetic alterations in patients with esophageal cancer with short- and long-term survival rates after curative esophagectomy

OBJECTIVE

The objective of this study was to ascertain the exact relation between specific oncogenes and long- and short-term survival rates in patients with esophageal cancer.

SUMMARY BACKGROUND DATA

Recent developments in molecular biology have shown that several oncogenes and suppressor genes are involved in the development of esophageal cancer. However, the role of these genes still is unknown.

METHODS

The clinical outcome of 84 cases of R0-resected esophageal carcinomas (from 1986-1993) and the molecular and biologic characteristics of these tumors were studied. The patients studied were divided into three groups, which were designated as follows: shortest term survivors (up to 6 months), short-term survivors (7-12 months), and long-term survivors (>5 years). These groups included 23, 17, and 44 subjects, respectively. For the genomic analysis, CyclinD1, int-2, murine double minute 2 (MDM2), retinoblastoma, p53, adenomatous polyposis coli (APC), deleted in colorectal carcinoma (DCC), and human papillomavirus were studied in these patients. The regrowth capability of primary cultures and the clinicopathologic characteristics of these patients also were analyzed.

RESULTS

The CyclinD1 and int-2 genes, which are located in the 11q13 chromosome, and the MDM2 gene were related to short survival. However, the p53 mutation and human papillomavirus infection were not related to short-term survival. The average ratio of genomic abnormalities to genes examined was higher in the shortest and short-term survival groups than in the long-term survival group. Regrowth capability in primary cultures also was related to short-term survival. Among the long-term survival patients, 7 (16%) of 44 cases suffered further cancer after esophagectomy.

CONCLUSIONS

These results suggest that the 11q13 amplicon and MDM2 may play an important role in the progression of esophageal cancer, and an accumulation of genomic abnormalities may result in poor prognosis. Careful follow-up testing for double cancer is needed in long-term survivors of esophageal cancer.

Establishment of a novel host, high-red yeast that stably expresses hamster NADPH-cytochrome P450 oxidoreductase: usefulness for examination of the function of mammalian cytochrome P450

A novel strain of Saccharomyces cerevisiae useful for expression studies of mammalian microsomal cytochrome P450s was established and named High-red yeast. Hamster NADPH-cytochrome P450 oxidoreductase (P450 reductase) cDNA to be introduced into yeast was isolated from a hamster liver cDNA library. The cDNA was 2421 bp long and contained an entire coding region for 667 amino acids. The NH2-terminal amino acid sequence deduced from the hamster P450 reductase cDNA was identical with that of the enzyme purified from hamster livers except for deletion of the initial methionine. A delta-sequence derived from yeast retrotransposon Ty was cloned and used as a sequence for homologous recombination in a yeast genome. S. cerevisiae YPH500 was transformed with a multi-integration cassette containing the expression unit of the hamster P450 reductase and the delta-sequence. The transformant showing the highest activity of the P450 reductase was named High-red yeast. High-red yeast carried more than six copies of the multi-integration cassettes in a single chromosome and retained the multi-integration cassettes over a period of 100 generations under nonselective culture conditions, indicating that this yeast was a mitotically stable transformant. The microsomes prepared from High-red yeast had 20 times the P450 reductase activity of the microsomes prepared from the parental yeast. Due to the high activity of the hamster P450 reductase, the 7-ethoxycoumarin deethylase activity of mouse CYP1A1 expressed in High-red yeast was 250 times higher than the activity of mouse CYP1A1 expressed in the parental yeast.