Incidence of hepatocellular carcinoma in transgenic mice expressing the hepatitis B virus X-protein

BACKGROUND/AIMS

Chronic infection with hepatitis B virus is a high-risk factor for hepatocellular carcinoma in humans. The HBV X-protein, a multi-functional viral regulator, has been suspected to play a positive role in hepatocarcinogenesis, as demonstrated by the high incidence of hepatocellular carcinoma in HBx-expressing transgenic mice, although it is still controversial. The aim of this study was to generate transgenic mice expressing the HBV X-gene under authentic promoter control and to test whether the gene products can cause hepatic tumors.

METHODS

Three transgenic mouse lines were generated by microinjecting the X-gene construct into hybrid (C57BL/6 x DBA) eggs. Gene expression was tested by protein and mRNA analyses. During an observation period of 18 months, mice were sacrificed and organs subjected to histologic examinations.

RESULTS

Grossly defined hepatocellular carcinomas reproducibly were observed in mice expressing the X-protein, which were investigated through six generations from the age of 11 to 18 months. Among 14 transgenic mice investigated from the age of 11 to 18 months, 12 were found to have hepatocellular carcinoma, grossly or microscopically. The lesion of the hepatocellular carcinoma disclosed a significant increase in the proliferating cell nuclear antigen in the nuclei.

CONCLUSION

The incidence of hepatocellular carcinoma (86%) in our HBV X transgenic mice may be highly significant, since, except for one case, HBV X-gene transgenic mice produced in other laboratories did not develop liver tumor or any other pathologic phenomena.

Carcinoma of the Pancreas

Carcinoma of the pancreas remains a formidable challenge for clinicians. Pancreatic cancer is the tenth most common type of new cancer, and according to estimates of the American Cancer Society, 29,000 new cases occurred in 1998. The relative frequency of the disease is compounded by its lethality. Pancreatic cancer accounts for 5% and 6% of cancer deaths among men and women respectively, making it the fourth leading site of cancer deaths. In 1998, an estimated 28,000 deaths from pancreatic cancer were expected. The five-year relative survival rate for pancreatic cancer between 1986 and 1993, as reported by the NCI Surveillance, Epidemiology, and End Results Program, was only 4%. Although this was a statistically significant increase from the 3% five-year survival rate for pancreatic cancer between 1974 and 1976 it remained the lowest survival rate among all reported sites. By comparison, survival for gastric and esophageal cancers during the more recent reporting period were 19% and 12% respectively.

Characterization of Korean native goat lactoferrin

We purified lactoferrin from the colostrum of the Korean native goat (Capra hircus) by ion-exchange chromatography using CM-Toyopearl 650M followed by affinity chromatography on AF-Heparin Toyopearl 650M. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis suggested the molecular mass of Korean native goat lactoferrin is 82 kDa with an iron saturation of 30% as estimated by spectroscopic analysis. Circular dichroism analysis shows goat lactoferrin molecule contains 24.5%, alpha-helix; 36.0%, beta-structure; 13.5%, beta-turn and 26.0%, unordered structure. Heparin binding affinity is the same as that of bovine lactoferrin, but lower than that of human lactoferrin. An analysis using synthetic peptides shows that the peptide from residue 22 to 31--WQRRMRKLGA--exerts a positive heparin-binding ability.

Cysteine protease is a major exotoxin of pathogenic luminous Vibrio harveyi in the tiger prawn, Penaeus monodon

The role of an extracellular cysteine protease, produced by pathogenic luminous Vibrio harveyi strain 820514 originally isolated from diseased tiger prawn (Penaeus monodon), in the disease process in the prawns was studied. The protease was lethal to P. monodon with an LD50 value of 0.3 microgram protein g-1 prawn. The lethal toxicity of the extracellular products (ECP) of the bacterium was neutralized by pre-incubation of the ECP with rabbit antiserum to the cysteine protease. Pre-incubation of ECP with CuCl2 (an inhibitor of cysteine protease) also inhibited toxicity. This suggests that cysteine protease is the major toxin produced by the bacterium. The present protease is the first toxic cysteine protease to be found in Vibrio species.

Hemostasis of tiger prawn Penaeus monodon affected by Vibrio harveyi, extracellular products, and a toxic cysteine protease

The effects of bacterial cells, extracellular products (ECP) and a purified cysteine protease of Vibrio harveyi on hemostasis and plasma components of tiger prawn (Penaeus monodon) were studied. The clotting ability of the hemolymph withdrawn from moribund prawns pre-injected with the bacteria, ECP, cysteine protease of PBS (control) was observed for 2 h at 25 C. Of these, only the control group was clottable while all the other groups were unclottable. A component of the plasma, previously identified as coagulogen-like protein, was further confirmed to be a coagulogen by the comparison of plasma with serum on non-reduced SDS-PAGE or using rabbit antiserum to the coagulogen-like protein (R alpha coagulogen) to neutralize the clotting ability of normal prawn hemolymph. The coagulogen was reduced in amount in plasma of moribund prawns after injection with the bacteria, ECP or cysteine protease while it apparently disappeared after pre-incubation with the ECP or cysteine protease for 2 h at 25 C compared with normal prawn plasma as observed in crossed immunoelectrophoresis (CIE) gels. The reduction of the amount of coagulogen in plasma of moribund prawns was also evident in CIE gels using R alpha coagulogen. In addition, the apparent disapperance of the coagulogen mentioned above was eventually proven to be due to the change of its migration rate in CIE gels after pre-incubation with ECP or cysteine protease, since the disappeared coagulogen arc (arc 2) (migrated into arc 1) could be visualized by using R alpha coagulogen or by reducing the time for pre-incubation from 2 h to 30 min. Thus, the effects of cysteine protease on plasma coagulogen observed in vitro and in vivo may markedly interfere with hemostasis leading to the occurrence of unclottable hemolymph. These complex events may significantly contribute to the pathogenicity of V. harveyi in the prawn.

Expression of vascular endothelial growth factor (VEGF) and its receptors during embryonic implantation in the golden hamster (Mesocricetus auratus)

Expression of vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) and its receptors (flt-1 and flk-1) during the peri-implantation period (days 3, 4, 5, 6 and 7 post coitus) in the golden hamster was investigated by in situ hybridization, immunohistochemistry and the reverse transcription/polymerase chain reaction (RT-PCR). Three days after mating, in situ hybridization and immunohistochemical staining revealed weak VEGF expression only in the uterine epithelium; this expression was similar to that seen at oestrus. Flt-1 but no flk-1 immunoreactivity was observed. At day 4, the subepithelial stroma and embryo displayed immunoreactivity for VEGF and flt-1, whereas endothelial cells expressed both flt-1 and flk-1. At day 5, immunoreactivity for both VEGF and its receptors was detected in decidual cells and vascular endothelial cells. Only a few embryonic cells expressed VEGF mRNA but strong signals were noted in decidual cells. The patterns of VEGF and VEGF receptor expression were the same in the day-6 and day-7 embryos and decidua, except for an increase in intensity as development progressed. Based on these findings, we conclude that, in addition to its known actions on endometrial angiogenesis and tissue swelling, VEGF may also facilitate the proliferation and differentiation of the endometrium and help to sustain the avascular embryo during this early stage of development.

Protease and virulence of the extracellular products produced by Vibrio carchariae after growth on various media

Protease and virulence of the extracellular products (ECP) of Vibrio carchariae strain EmI82KL, a causative agent of gastroenteritis in Epinephelus coioides, cultured on different media were studied. The bacteria grown on peptone agar, nutrient agar or brain heart infusion agar produced higher protease activities than that grown on tryptic soy agar (TSA) in terms of protein content. The addition of ethylenediamine di(o-hydroxyphenylacetic acid) or horse serum in TSA enhanced the ECP protease production while the addition of grouper serum apparently reduced the enzyme activity indicating the presence of protease inhibitor(s) in the fish serum. Furthermore, the use of grouper meat or peptone as a single nutrient source remarkably enhanced the production of ECP protease. Adding proteinaceous materials from animal sources (horse serum, grouper meat or peptone) on agar manifested higher ECP protease activity than that from plant source (TSA), indicating the intestine of carnivorous groupers might favour the existence, survival or infection of the bacterium. The protease was a metal-chelator-sensitive serine protease since it was inhibited by 3,4-dichloroisocoumarin and phenylmethanesulfonyl fluoride while about 80% of its activity inhibited by chelating agents (ethylene-diaminetetraacetic acid and ethylene glycol-bis(beta-amino-ethylether) N,N,N',N'-tetraacetic acid). The ECP obtained from each medium was not lethal to the groupers suggesting that the bacterium is low virulent. As grouper is carnivorous, therefore, the role of the protease played in the fish intestine probably is competing for nutrients and/or associated with the cause of edema leading to gastroenteritis.

Identification of a novel cis-acting positive element responsible for the cell-specific expression of the NK-1 homeobox gene

The Drosophila NK-1 homeobox gene belongs to the NK-1 class that includes a large number of vertebrate homeobox genes and is shown to be expressed in specific muscle founder cells and a subset of neuronal cells in the ventral nerve cord during embryogenesis. To determine the cis-acting regulatory elements controlling the cell-specific expression of NK-1, we measured transiently expressed chloramphencol acetyl transferase (CAT) reporter gene activities from transfected C2C12 myoblasts and NG108-15 neuroblastoma cells using various CAT constructs containing different 5' upstream regions of NK-1. From the initial analysis of 3.9 kb of the 5' upstream region, we have found that the regions from -1865 to -476 and from -476 to +100 contained strong negative and positive regulatory elements, respectively. Within the positive cis-acting region an 86-bp DNA fragment (from -435 to -350) was sufficient to activate the reporter gene in C2C12 cells, whereas additional regions (from -157 to -28 and from -510 to -425) were required for optimal activity in NG108-15 cells. Gel shift and DNaseI footprinting assays have defined a plausible binding site for C/EBP, 5'-TTTCGCAAG-3' (-424 to -416), and a novel binding site for unknown factors, 5'-AATTACTCACATCC-3' (-370 to -357). Further mutation analysis has revealed that the novel binding sequence for unknown factors is necessary and sufficient for transcriptional activity for reporter gene expression in C2C12 myoblast cells in an orientation-independent manner.

Self-medication among university students in Hong Kong

Five hundred and sixty-three university students were interviewed to survey the practice of self-medication which was found to be very prevalent (94.0%). The most commonly used items included remedies for cough and cold, antipyretics and analgesics. Topical preparations and Chinese herbal medicines were also frequently consumed. Self-medication items were mostly obtained from home medicine cabinets and pharmacy shops (not necessarily staffed by registered pharmacists) and they also relied heavily on family members and previous illness experience for information on the medications they took. The healthcare professionals only played a minor role in the provision of drug information. Nevertheless, the concept of self-medication is well-established among these university students as they recognised that minor illness could be cared for without seeing a doctor. Healthcare professionals should assume more active roles in the provision of drug information and counselling so that a good self-care programme could be established.

gas2 is a multifunctional gene involved in the regulation of apoptosis and chondrogenesis in the developing mouse limb

The growth-arrest-specific 2 (gas2) gene was initially identified on account of its high level of expression in murine fibroblasts under growth arrest conditions, followed by downregulation upon reentry into the cell cycle (Schneider et al., Cell 54, 787-793, 1988). In this study, the expression patterns of the gas2 gene and the Gas2 peptide were established in the developing limbs of 11.5- to 14. 5-day mouse embryos. It was found that gas2 was expressed in the interdigital tissues, the chondrogenic regions, and the myogenic regions. Low-density limb culture and Brdu incorporation assays revealed that gas2 might play an important role in regulating chondrocyte proliferation and differentiation. Moreover, it might play a similar role during limb myogenesis. In addition to chondrogenesis and myogeneis, gas2 is involved in the execution of the apoptotic program in hindlimb interdigital tissues-by acting as a death substrate for caspase enzymes. TUNEL analysis demonstrated that the interdigital tissues underwent apoptosis between 13.5 and 15.5 days. Exactly at these time points, the C-terminal domain of the Gas2 peptide was cleaved as revealed by Western blot analysis. Moreover, pro-caspase-3 (an enzyme that can process Gas2) was cleaved into its active form in the interdigital tissues. The addition of zVAD-fmk, a caspase enzyme inhibitor, to 12.5-day-old hindlimbs maintained in organ culture revealed that the treatment inhibited interdigital cell death. This inhibition correlated with the absence of the Gas2 peptide and pro-caspase-3 cleavage. The data suggest that Gas2 might be involved in the execution of the apoptotic process.

Hepatocyte growth factor stimulates chemotactic response in mouse embryonic limb myogenic cells in vitro

In this study we investigate the influence of Hepatocyte Growth Factor (HGF) on the motility of embryonic forelimb myoblasts. Using Blindwell chemotactic chambers, it was found that HGF at concentrations of 1-50 ng/ml dramatically enhanced the ability of myogenic cells to migrate. This stimulatory effect was elicited in a dose-dependent fashion and the effect was reversed with the addition of HGF neutralizing antibodies. A checkerboard analysis was performed and it revealed that HGF's effect on limb myoblast motility was through both chemokinesis and chemotaxis. HGF was also examined for its ability to stimulate myogenic cell proliferation, using MF20 antibody as the myogenic marker. At all concentrations tested, HGF did not stimulate an overall increase in the numbers of MF20-positive myoblasts in culture. To examine the chemokinetic effect of HGF on cell migration in the limb, cells were isolated from the proximal regions of the limb (areas rich in myogenic cells), exposed to HGF, labeled with DiI and transplanted into 11.5 day mouse forelimbs. After 36 h of culture, it was found that DiI-labeled limb cells, pretreated with HGF, migrated significantly further in the limb than labeled cells that have not been exposed to HGF. The chemotactic effect of HGF was also investigated by implanting beads loaded with and without HGF into the 11.5 day limb. Proximal to the beads, DiI-labeled limb cells were also transplanted. It was found that HGF was able to chemotactically attract and direct the migration of DiI-labeled limb cells. Immunohistological staining was performed with HGF antibodies to determine the distribution of HGF in the 11.5 day mouse forelimb. It was found that HGF was strongly expressed by the apical ectodermal ridge (AER), the ectoderm and the mesenchyme directly beneath the AER. Positive staining was also obtained for the myogenic regions. However, the pattern was heterogeneous--punctuated with myogenic cells expressing and not expressing HGF.

Structure of the human lactoferrin gene and its chromosomal localization

The complete gene encoding the human lactoferrin (hLf) was isolated from a cosmid library and its structure was characterized. A detailed restriction map and the complete exon-intron structure of the gene are presented. The transcript is assembled from 17 exons like the bovine (bLf) and murine lactoferrin (mLf) genes, which are separated by introns ranging in size from about 300 bp to 3.3 kb. The total length of the gene is about 24.5 kb, estimated by adding up the sizes of the exons and introns. A comparison of the structure of the hLf gene with that of other species revealed that the hLf gene is more closely related to bLf than to mLf. The positions of the introns were well matched with those of the bLf gene except only for exons 14 and 15, wherein exon 14 of the hLf gene is one nt shorter while exon 15 is one nt longer than the bLf gene. All the exon-intron boundaries of the gene conformed to the GT/AG rule. In situ fluorescence hybridization indicated that the hLf gene was mapped in the region 3p21.3.

Charge collection and radiation hardness of a SOI microdosimeter for medical and space applications

The first results obtained using a SOI device for microdosimetry applications are presented. Microbeam and broadbeam spectroscopy methods are used for determining minority carrier lifetime and radiation damage constants. A spectroscopy model is presented which includes the majority of effects that impact spectral resolution. Charge collection statistics were found to substantially affect spectral resolution. Lateral diffusion effects significantly complicate charge collection.

Comparison of laparoscopic versus open repair of paraesophageal hernia

BACKGROUND

Recent reports suggest that laparoscopic paraesophageal hernia repair (LPHR) is feasible, but no direct comparisons with the standard open paraesophageal hernia repair (OPHR) have been reported. The purpose of this study was to compare the short-term outcome of LPHR versus OPHR at a single institution.

METHODS

The operative and postoperative courses of 95 consecutive patients undergoing open or laparoscopic repair of a paraesophageal hernia (PEH) were retrospectively reviewed, and outcomes of LPHR versus OPHR were compared.

RESULTS

PEH was associated with advanced age and significant comorbidity. Although the operative time was increased for LPHR, there was a significant reduction in blood loss, intensive care unit stay, ileus, hospital stay, and overall morbidity associated with LPHR compared with OPHR.

CONCLUSIONS

PEH is associated with significant comorbidity that increases the operative risk. Short-term outcomes for LPHR are superior to OPHR, suggesting that the laparoscopic approach is the preferred approach to paraesophageal hernia repair.

Diagnostic and therapeutic value of nonhysteroscopic transvaginal falloposcopy with a linear everting catheter

BACKGROUND

Before the advent of the falloposcope, the endosalpinx usually evaded endoscopic evaluation. The healthy condition of the tubal epithelium and the patency of the tube are important for development and transportation of early stage embryos.

METHODS

Twenty patients had tubal occlusion diagnosed by hysterosalpingography, including 10 cases of hydrosalpinx, five cases of interstitial occlusion and five cases of fimbrial occlusion. Falloposcopy with a linear everting catheter and laparoscopy were performed simultaneously to evaluate tubal lumens and peritubal conditions.

RESULTS

An attempt was made to cannulate 30 fallopian tubes in 20 cases with a falloposcope, using a nonhysteroscopic transvaginal approach through a linear everting catheter. The success rate was 93% (28/30). In 15 cases of hydrosalpinx or fimbrial obstruction, 10 patients (67%) were considered to be suitable for in vitro fertilization because of flattened mucosa in the endosalpinx and endotubal adhesions. Normal mucosa was noted in only four patients (27%), who were advised to have tuboplasty. One patient (6%) had normal mucosa without tubal occlusion. In two of the five cases of interstitial occlusion, dye (methylene blue) could not pass the interstitial portion of the fallopian tube when chromopertubation was performed twice. This tubal obstruction was overcome with the linear everting catheter. One patient had the complication of an ampulla wall perforation.

CONCLUSIONS

In patients with fallopian tube disease, falloposcopy is a useful technique for evaluating the endosalpinx and providing information for selecting further treatment. In some cases of interstitial occlusion, it may also have a therapeutic effect.

Isolation and structure elucidation of new PKCalpha inhibitors from Pinus flexilis

Bioassay-guided fractionation of the CH2Cl2-MeOH extract of Pinus flexilis using an assay for protein kinase C (PKC) inhibitory activity led to the isolation of the two new bioactive diarylheptanoids (3R)-1,7-bis(3, 4-dihydroxyphenyl)-3-(beta-D-glucopyranosyl)heptan-3-ol (1) and its aglycon (3R)-1,7-bis(3,4-dihydroxyphenyl)heptan-3-ol (2), together with the three known bioactive compounds, hirsutenone (3), oregonin (4), and hirsutanonol (5). The IC50 values of compounds 1-5 in the PKC assay were 1.4, 1.6, 1.4, 8.6, and 4.6 microg/mL, respectively.

Sensory recovery in noninnervated radial forearm free flaps in oral and oropharyngeal reconstruction

BACKGROUND

Reinnerveration of free flaps used in oral and oropharyngeal reconstruction may provide a high level of sensory return. Spontaneous recovery of sensation in noninnervated flaps may also occur.

OBJECTIVE

To evaluate the extent of spontaneous sensory return among patients who underwent radial forearm free flap reconstruction in the oral cavity and oropharynx.

METHODS

A total of 40 patients were evaluated by 2 independent examiners. The median patient age was 60 years, and the median time from surgery was 47 months. A total of 29 patients had received postoperative radiotherapy. The mean flap size was 25 cm2. The following sensory modalities were tested: light touch, pinprick, hot and cold, and moving and static 2-point discrimination.

RESULTS

Recovery of sensation of at least 1 modality was noted in 32 patients (80%), however, only 5 patients (13%) had return of all 5 modalities. Eight patients (20%) had no sensory return. There was a trend to improved sensory recovery in flaps placed in the alveolar and retromolar trigone areas; however, on multivariate analysis, sensory return could not be predicted by any of the following factors: patient age, flap site, flap size, length of follow-up, and use of postoperative radiotherapy.

CONCLUSIONS

Complete sensory recovery was uncommon, unpredictable, and variable, although some recovery of sensation occurred in 80% of patients. It is not valid to rely on spontaneous sensory recovery for sensory innervation of free flaps. Correlation of sensory return with function is still needed.

Matrix attachment region sequences enhanced the expression frequency of a whey acidic protein/human lactoferrin fusion gene in the mammary gland of transgenic mice

To elevate the expression frequency of transgenes in transgenic mice, the chicken lysozyme matrix attachment region (MAR) sequence was used by combining it with a transgene. The whey acidic protein (WAP) promoter/human lactoferrin (hLF) cDNA fusion transgene (pWL) was connected to the chicken lysozyme MAR sequence at its 5'-end (pMWL). While only two of three mice became transgenic from the pWL vector expressed hLF, all seven mice from the pMWL vector expressed the transgene in their lactating mammary glands. To evaluate the effect of lactogenic hormones on transgene expression, experiments with the primary culture of transgenic mammary explants were performed. It was revealed that the expression of transgenes was slightly increased by insulin plus dexamethasone or insulin plus prolactin treatment. However it was not increased by insulin, dexamethasone or prolactin (IDP) treatment alone. In contrast, the endogenous WAP gene was expressed only in the IDP treated group. These results demonstrate that MAR sequences are effective in improving the expression frequency of transgenes in transgenic mice although the developmental and hormonal regulations are not the same as those of the endogenous WAP gene.

Evaluation of 250 free-flap reconstructions after resection of tumours of the head and neck

BACKGROUND

Microvascular free-tissue transfer is now the primary method of reconstruction in many centres. The aim of this study was to evaluate the applications, complications and limitations of free-flap reconstruction in a series of patients with tumours of the head and neck.

METHODS

This study reviewed prospectively accessioned computerized records in a dedicated head and neck database. Patients treated between 1987 and 1995 with a minimum of a 1-year follow-up were reviewed. There were 242 patients with a mean age of 58 years (172 men and 70 women). The most common tumour sites were oral cavity (42%), oropharynx (32%) and hypopharynx (11%). Mucosal squamous carcinoma accounted for 87% of primary cancers.

RESULTS

Among the 250 free flaps, the radial forearm flap (205) and free jejunum (25) predominated. There were 21 episodes of vascular occlusion (8%), failure of 10 flaps (4%) and two patients died peri-operatively (0.8%). A second free flap was used in five of 10 cases of flap failure. The fistula rate was 4.4% among 203 patients at risk for this complication, which comprised four of 178 forearm flaps and five of 25 free jejunal grafts. Four of 16 jaw reconstructions failed.

CONCLUSIONS

A 96% success rate was achieved using free-tissue transfer for head and neck reconstruction. The overall complication rate was low but jaw reconstruction and free jejunal grafts posed the greatest problems because of failure of radial bone and fistulas, respectively. The radial forearm septocutaneous flap was very reliable and remains our mainstay for oral reconstruction.

The type II peroxiredoxin gene family of the mouse: molecular structure, expression and evolution

Peroxiredoxins (Prxs) are a newly defined family of antioxidant proteins that have been implicated, via their antioxidant activity, in a number of cellular functions, including cell proliferation and differentiation, protection of other proteins from oxidative damage, and intracellular signaling. We isolated genomic DNA sequences of the type II Prx (Prx II) gene from the mouse and analyzed their molecular genetic characteristics. In the mouse, the Prx II is found to form a small multigene family with three members. One of them, the Prx II-1 gene, is actively transcribed in a variety of adult tissues as well as in the developing embryos to produce a 1.1-kb mRNA. The Prx II-1 gene consists of six exons and five introns, and the whole transcription unit occupies about 4.5 kb in the mouse genome. The other two genes, Prx II-2 and Prx II-3, are encoded by single exons, and show 97.5 and 87% of nucleotide sequence homology with the Prx II-1 gene, respectively. Structural features of these genes and the results of RT-PCR analysis on RNAs from various tissue sources indicate that the Prx II-2 and Prx II-3 genes could be pseudogenes derived from the Prx II-1 gene by a mechanism involving retrotransposition. These results strongly suggest that only the Prx II-1 gene might be relevant for studying the function of the Prx II gene in the murine system.

Congenital varicella-zoster virus infection and Barrett's esophagus

Congenital varicella syndrome is a rare complication of varicella-zoster virus (VZV) infection during pregnancy. An infant was exposed to VZV at 18.5 weeks of gestation and had eye and skin abnormalities at birth and persistent feeding difficulties, prompting esophageal biopsies at 12 days and 20 and 20.5 months of age. Esophageal tissues demonstrated specialized intestinal metaplasia (Barrett's esophagus). VZV DNA (in situ hybridization) and proteins (immunohistochemistry and polymerase chain reaction) were found in esophageal epithelial cells adjacent to the Barrett's lesion. Immediate-early 63 protein (IE63) of VZV was demonstrated in the day 12 specimen, and IE62 and the late VZV glycoprotein E (gE) were found in the 20-month specimen. Clinical and endoscopic improvement followed fundoplication and acyclovir therapy, but VZV DNA and IE62 persisted in esophageal tissue. These findings associate VZV with specialized intestinal metaplasia within the esophagus and suggest a novel site for either latent or active VZV infection.

Differential effects of nongenotoxic and genotoxic carcinogens on the preneoplastic lesions in the rat liver

Glutathione S-transferase placental form (GST-P) positive foci development and its expression in liver exposed by nongenotoxic carcinogens phenobarbital (PB) and clofibrate (CF), and genotoxic carcinogen 2-amino-3-methylimidazo[4,5-f] quinoline (IQ) were investigated as a measure of carcinogenic potential of these chemicals. Male F344 rats were initially given a single intraperitioneal injection of diethylnitrosamine (200 mg/kg), and 2 weeks later, animals were fed diets containing 0.03% IQ or 0.5% CF or 0.05% PB or basal diet as a control for 6 weeks. All rats were subjected to two-thirds partial hepatectomy (PH) at week 3. Sequential sacrifice of rats was performed at 8 weeks or 52 weeks, and liver tissues were examined for immunohistochemical staining of GST-P positive foci. The numbers (No./cm2) and areas (mm2/cm2) of GST-P positive foci were increased by IQ or PB, but were decreased by CF compare to the control. Consistent with the development of GST-P positive foci, a time-related increase in the expression of GST-P mRNA was found in the rats treated with IQ, whereas CF decreased it. The incidence of hepatocellular carcinoma at 52 weeks was increased by all three chemicals. These results show that PB and IQ induced GST-P positive foci, but the peroxisome proliferator CF did not, which suggest that the prediction of carcinogenic potency based on the development of prenoplastic foci may cause false negative in a particular category compounds like peroxisome proliferators.

Purification, molecular cloning, and characterization of TRP32, a novel thioredoxin-related mammalian protein of 32 kDa

We purified a protein of 32 kDa from human thymoma HPB-ALL cells that was co-purified with a catalytic fragment of MST (mammalian STE-20-like), a kinase of the STE20 family, which is proteolytically activated by caspase in apoptosis (Lee, K.-K., Murakawa, M., Nishida, E., Tsubuki, S., Kawashima, S., Sakamaki, K., and Yonehara, S. (1998) Oncogene 16, in press). Molecular cloning of the gene encoding this 32-kDa protein (TRP32) reveals that it is a novel protein of 289 amino acid residues and contains an NH2-terminal thioredoxin domain with a conserved thioredoxin active site. The human and mouse TRP32 proteins have 99% homology, and the thioredoxin domains are completely identical. The thioredoxin domain of TRP32 has thioredoxin-like reducing activity, which can reduce the interchain disulfide bridges of insulin in vitro. However, the thioredoxin domain of TRP32 is more sensitive to oxidation than human thioredoxin. Northern blot analysis showed that TRP32 is expressed in all human tissues. Expression of TRP32 was also confirmed in all mammalian cell lines tested by Western blot analysis using anti-TRP32 monoclonal antibody. Subcellular fractionation and immunostaining analysis showed TRP32 is cytoplasmic protein. These findings suggest that TRP32 is a novel cytoplasmic regulator of the redox state in higher eukaryotes.