Expression of the pancreatic secretory trypsin inhibitor gene in the liver infected with hepatitis B virus

Pancreatic secretory trypsin inhibitor, an acute phase reactant protein, is expressed in the liver in response to inflammatory cytokines, especially in hepatocellular carcinoma. Northern blots of 25 dissected liver tissues from non-hepatitis, chronic hepatitis and cirrhosis patients revealed that 10 (40%) expressed pancreatic secretory trypsin inhibitor. The expression seemed to be closely associated with hepatitis B viral infection, since among the 11 hepatitis B virus-infected samples, nine (81%) were pancreatic secretory trypsin inhibitor-positive. In contrast, this augmented expression was absent in non-infected livers (0/5; 0%), and rare in those infected with hepatitis C virus (1/9; 11%). There was no significant correlation between the pancreatic secretory trypsin inhibitor expression in the liver and the serum level of glutamic pyruvic transaminase, the hepaplastin test, the 15-min retention rate of indocyanine green, or the histological findings of the liver tissues such as lymphocyte infiltration and pseudolobular formation. Furthermore, we identified an almost three-fold increase in the transactivation of pancreatic secretory trypsin inhibitor gene expression in HepG2 cells after transient transfection with HBV-DNA or the X gene in an expression vector. These results suggest that the induction of pancreatic secretory trypsin inhibitor gene expression in livers with chronic hepatitis and cirrhosis is directly affected by hepatitis B virus.

Pyrrolidine dithiocarbamate, a potent inhibitor of nuclear factor kappa B (NF-kappa B) activation, prevents apoptosis in human promyelocytic leukemia HL-60 cells and thymocytes

We examined the effect of pyrrolidine dithiocarbamate (PDTC), which potently blocks the activation of nuclear factor kappa B (NF-kappa B), on the induction of apoptosis by a variety of agents. Treatment of a human promyelocytic leukemia cell line, HL-60, with 10 micrograms/mL etoposide or 2 microM 1-beta-D-arabinofuranosylcytosine induced NF-kappa B activation within 1 hr and subsequently caused apoptosis within 3-4 hr. The simultaneous addition of 50-500 microM PDTC with these agents blocked NF-kappa B activation and completely abrogated both morphologically apoptotic changes and internucleosomal DNA fragmentation for up to 6 hr. However, PDTC failed to inhibit the endonuclease activity contained in the whole cell lysates. The inhibitory effect of PDTC was also observed in etoposide- and dexamethasone-induced apoptosis in human thymocytes at a concentration of 1-10 microM. Since PDTC has both antioxidant and metal-ion chelating activities, we tested the effects of N-acetyl-L-cysteine (NAC) (antioxidant) or o-phenanthroline (OP) (metal-ion chelator) on the induction of apoptosis. Pretreatment of HL-60 cells or thymocytes with 100-500 microM OP for 2 hr, but not 10-60 mM NAC, suppressed subsequent occurrence of apoptosis induced by etoposide. These results suggest that the activation of NF-kappa B plays an important role in the apoptotic process of human hematopoietic cells.

Chromosomal assignments of 3'-directed partial cDNA sequences representing novel genes expressed in granulocytoid cells

Large scale cDNA sequencing of 3'-directed cDNA libraries allows the collection of hundreds of novel sequences (gene signatures) and understanding of their expression levels in various tissues. Granulocytoid cells were induced from the human promyelocytic leukemia cell line 60 (HL60) with dimethyl sulfoxide (DMSO), and more than 1000 gene signatures were collected from a 3'-directed cDNA library of the granulocytoid cells. By selecting appropriate sequences for primer design, we systematically assigned chromosomes of these novel gene signatures by means of the polymerase chain reaction. We used a monochromosomal hybrid cell panel DNA as the template and localized 155 gene signatures to individual chromosomes. The results showed that 125 of them were assigned to single chromosomes and 30 to more than one. Genes assigned to more than one chromosome tend to be expressed ubiquitously, and their sequences are often conserved among humans and rodents. A highly sensitive laser fluorescent analyzer and ethidium staining were used for simple and large-scale PCR mapping.

The addition of 5'-coding information to a 3'-directed cDNA library improves analysis of gene expression

Large-scale sequencing of a 3'-cDNA library permits one to analyse gene expression profiles in various tissues. However, many such sequences lack enough information about the encoded proteins. To overcome this problem, we tested a new library, consisting of a 3'-directed cDNA sequence fused to a to a 5' sequence of about 300 bp. Such 'joint molecules' of about 600 bp were amplified by PCR and directly sequenced. About 40% of these joint molecules included the 5' and 3' terminal portions of the mRNA, and most of the remaining clones contained the middle portion and 3' end of the mRNA. The upstream sequences contained sufficient information with which to search for similarity, ORFs, motifs and hydropathy, thus allowing the mRNAs to be categorized and their functions predicted. The rapid categorization of the cDNAs will help to sort those clones that merit further analysis.

In vivo administration of granulocyte colony-stimulating factor promotes neutrophil survival in vitro

We recently showed that recombinant human granulocyte-colony stimulating factor (rhG-CSF) maintained the viability of human neutrophils in incubation for up to 72 hours. However, it is not known whether rhG-CSF can enhance neutrophil survival in in vivo situations. To clarify this issue, we investigated neutrophil survival in vitro following in vivo injection of rhG-CSF. Neutrophils were obtained from 4 pediatric patients with malignancies and healthy adult volunteers before and after rhG-CSF administration. Neutrophils obtained before rhG-CSF treatment started to undergo apoptosis after 24 h of incubation. In contrast, the survival of neutrophils drawn after rhG-CSF administration increased by approximately 24 h. Concomitantly, the appearance of typical ladder-like DNA fragmentation was delayed. Such an increase in neutrophil survival was inhibited by co-incubation with either H 7 (10 mumol/l) or H 8 (20 mumol/l), which worked as protein kinase C inhibitors. Although our study did not measure neutrophil survival in vivo directly, it provides us with further evidence that rhG-CSF may function to prolong neutrophil life expectancy in vivo.

Effect of cadmium (CdCl2) on cell proliferation and production of EDRF (endothelium-derived relaxing factor) by cultured human umbilical arterial endothelial cells

The effect of cadmium chloride (CdCl2) on cell proliferation and EDRF (endothelium-derived relaxing factor) production by cultured human umbilical arterial endothelial cells (HUAECs) was investigated. The viability of HUAECs decreased dose-dependently after the addition of Cd (cadmium chloride). Morphologic examination by phase contrast microscopy revealed severe damaging effects of Cd at higher concentrations. The cytotoxic effect of Cd on DNA synthesis was also concentration-dependent. The effect of Cd on EDRF production by indomethacin-treated HUAECs was assessed by its anti-platelet aggregatory effect. Platelet aggregation studies were carried out in cuvettes lined with HUAECs using an aggregometer. The anti-platelet aggregatory effect was decreased dose-dependently by pretreatment with Cd. These findings suggest that HUAECs are susceptible to concentration-dependent Cd cytotoxicity, and that Cd can inhibit the production of EDRF by HUAECs.

The packaging signal in hepatitis B virus pregenome functions only at the 5' end

When the hepatitis B virus (HBV) replicates, a full-size transcript of the viral genome, called pregenome RNA, is made and is selectively packaged into virus core particles. This selective encapsidation is dependent upon the presence of a specific cis-acting sequence called the packaging signal that is found at the 5' end of the pregenome RNA. Deletion analysis revealed that this packaging signal was located in a 70 bp stretch of nucleotides. Packaging defective virus genome containing the 70 bp packaging signal sequence at several locations, showed that the packaging occurs effectively only when the signal is located near the 5' end of the pregenome RNA. Packaging also occurred with a 2.4 kb viral RNA whose 5' region sequence was different from that of the pregenome RNA, but which has the packaging signal sequence inserted at the 5' region.

Somatic mutations at T-cell antigen receptor and glycophorin A loci in pediatric leukemia patients following chemotherapy: comparison with HPRT locus mutation

Frequencies of somatic mutations in pediatric patients with leukemia were evaluated following intensive treatment at three different loci: the hypoxanthine-guanine phosphoribosyl transferase (HPRT), T-cell antigen receptor (TCR), and glycophorin A (GPA) gene. Thirty-two children with acute lymphoblastic leukemia (ALL), nine children with acute myelogenous leukemia (AML), and 20 age-matched healthy controls were included in the study of mutant frequencies (Mfs) at the HPRT and TCR loci. Among these patients and controls, individuals with heterozygous MN blood type, i.e., 14 children with ALL, three children with AML, and nine healthy controls, served for the further assessment of variant frequency (Vf) at the GPA locus. In ALL patients, geometric mean Mfs and Vfs at these loci were significantly higher than in healthy controls. The high Mf value at the HPRT locus persisted for up to 8 years after the end of chemotherapy. On the other hand, the Mf values at the TCR locus and Vf values at the GPA locus declined gradually with time. In AML patients, on the other hand, the geometric mean Mf only at the TCR locus was significantly higher than in the controls, albeit to a lesser degree than in ALL patients. These data suggest that anti-cancer therapy induces somatic mutations at various loci and that ALL patients are more susceptible to mutagenic intervention than are AML patients.

Structural studies of condensation products of biogenic amines as inhibitors of tryptophan hydroxylase

The effects of condensation products of dopamine and indoleamines on the activity of tryptophan hydroxylase (TPH) were evaluated to determine the structures associated with modulation of this enzyme activity. The compounds having a catechol structure, such as 1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, markedly inhibited the activity of the enzyme prepared from the rat brain. The inhibition was non-competitive in terms of both the biopterin cofactor and the substrate L-tryptophan. Substitution on the one or two positions of catechol isoquinolines did not affect the inhibitory activity towards TPH. Among these compounds, a charged substance, 1,2[N]-dimethyl-6,7-dihydroxy-isoquinolinium ion, was an extremely potent inhibitor; the Ki values were 0.88 +/- 0.17 and 0.64 +/- 0.08 microM (mean +/- S.D.) in terms of the substrate and cofactor, respectively. By contrast, the condensation products of tryptophan and tryptamine with acetaldehyde scarcely affected TPH activities. 1-Methyl-1,2,3,4-tetrahydroisoquinoline, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 1-methyl-4-phenylpyridinium ion (MPP+) were almost inactive. These results indicated that the catechol structure recognized and combined with TPH at a binding site different from that of the substrate or cofactor and the positive charge on the dopamine-derived substance enhanced the affinity to TPH. The selective inhibition of TPH by dopamine-derived catechol isoquinolines was discussed in relationship to the interactions between catecholamines, indoleamines and their metabolites in the brain under physiological and pathological conditions.

A novel assay for typing Rh antigens in blood-stains using a lectin specific to the bisecting N-acetyl-D-glucosamine side chain of glycoprotein

A unique sandwich enzyme-linked immunosorbent assay for the determination of Rh antigens in blood stains has been developed using Rh antisera and phaseolus vulgaris E4/peroxidase conjugate (PHAE4/PO). The appropriate antiserum for detecting Rh C, c, D, E or e was coated on the inner surface of microplate wells, and the sample antigens from blood stains, solubilized with n-octyl-beta-D-glucopyranoside, were then placed in the wells. After washing the wells repeatedly, PHAE4/PO was added. Bound PHAE4/PO was detected by the development of colors using o-phenylenediamine/H2O2. All Rh antigens corresponding to the antisera were clearly detected using this technique. The detection limit expressed by sample dilution was more than 2 x 10(5) times (volume/dried blood weight) for the various antigens from the fresh 5 x 5 mm2 blood stain. Even when the blood stain samples were left beside a sunny window at room temperature for 2 months, Rh antigens were still detected. When the ABH, MN, P1, Kidd, Duffy and Lewis blood grouping systems were tested with similar ELISA procedures PHAE4 did not recognize any antigen. Since PHAE4 specifically recognizes and combines with the bisecting N-acetyl-D-glucosamine side chain, it was concluded that the glycoprotein was a component of all Rh antigens immune complexes.

Variable susceptibility to apoptosis induced by calcium ionophore in hybridomas between HL-60 promyelocytic and CEM T-lymphoblastic leukemia cell lines: relationship to constitutive Mg(2+)-dependent endonuclease

We recently reported that treatment with calcium ionophore, A23187, induces apoptosis in human myelogenous leukemia cells but causes necrotic cell death in T-lymphoblastic leukemia cells. To better understand the underlying mechanisms of such different modes of cell death, we established hybridomas between HL-60 promyelocytic and CEM T-lymphoblastic leukemia cells. The resulting hybridomas were divided into three groups in terms of their susceptibility to apoptosis following exposure to A23187: (1) hybridomas highly sensitive to apoptosis, (2) hybridomas with intermediate sensitivity to apoptosis which occurs later and to a lesser extent, and (3) hybridomas resistant to apoptosis. However, growth inhibition after 72 h of incubation and an initial rise in intracellular free calcium concentrations induced by A23187 were similar in the three groups. Expression of Ca(2+)-independent/Mg(2+)-dependent endonuclease, which had an optimal pH of 7.5-8.5 and was inhibited by Zn2+, was correlated with the susceptibility of the hybridomas to A23187-induced apoptosis. Thus, this endonuclease may play, at least in part, an important role in the induction of apoptosis in leukemia cell lines. Analysis of hybridomas between apoptosis-sensitive and apoptosis-resistant cells is useful in the elucidation of genetic factors which regulate cell death.

Identification of cellular proteins that bind the central conserved region of p53

The bacterial fusion protein between glutathione S-transferase and the central conserved region of human p53(GST-p53) was purified and fixed on the beads and then used in the binding assay with radiolabeled cell extract from human hepatocarcinoma cell line, Hep3B. The binding assay disclosed the presence of cellular proteins that interact with GST-p53 but not with GST. SV40 large T antigen abrogated the bindings of two cellular proteins with molecular weights of 50 kda and 40 kda. The binding of the proteins to p53 was observed in a cell cycle-dependent manner. These two proteins are candidate cellular proteins which regulate the function of p53.

Chromosomal assignment of HepG2 3'-directed partial cDNA sequences by Southern blot hybridization using monochromosomal hybrid cell panels

Large-scale sequencing of a 3'-directed cDNA library from the human liver cell line HepG2 has generated several hundred species of cDNA gene signatures, about 85% of which identify novel genes. They are useful molecular landmarks for human genome mapping. We used 160 of these novel signatures as probes for Southern hybridization to human DNA. We then identified the copy number of the corresponding genes and assigned them to chromosomes, with reference to monochromosomal hybrid cell mapping panels. The distribution profile of the expressing genes among chromosomes suggested that the expressing gene density is not uniform.

Heterogeneities in ferritin dimers as characterized by gel filtration, nuclear magnetic resonance, electrophoresis, transmission electron microscopy, and gene engineering techniques

To understand the mechanism underlying the preferential dimerization of ferritin shells, we studied monomers and dimers from both horse spleen and recombinant horse L-apoferritin by using gel filtration, nuclear magnetic resonance, electrophoresis, transmission electron microscopy, and gene engineering techniques. Our study of the kinetics of dimer-monomer dissociation that is produced by heating revealed the presence of at least two types of dimers, namely, weakly and strongly linked dimers with activation energies of 124 +/- 14 and 157 +/- 16 kJ/mol, respectively. Our study using thiol reagents indicated that the dimerization in horse spleen ferritin is partially mediated by disulfide bridges being formed between H-chains. Our analysis of the components that resulted from the dimer-monomer dissociation further clarified that these dimers form interdigitation structures. In summary, five types of dimers were identified in horse spleen apoferritin: reversible dimers with very weak interaction, non-sulfide dimers with weak interaction, non-sulfide dimers with strong interaction, disulfide dimers linked only by disulfide bridges, and disulfide dimers linked by disulfide bridges and having other interactions.

A fatal disaster case based on exposure to hydrogen sulfide--an estimation of the hydrogen sulfide concentration at the scene

Four adult men fell into an artificial lake which was being used to raise flatfish, after a water pipe had been connected to a tube allowing seawater to flow into the lake. Forensic autopsies were carried out on three of the four men, who died soon after the incident. From autopsy findings, the cause of death was diagnosed to be suffocation after aspirating seawater in the three victims. To clarify why the men fell into the lake, a chemical analysis for hydrogen sulfide was carried out using the extractive alkylation technique combined with gas chromatography/mass spectrometry. The sulfide was detected as its derivative, bis(pentafluorobenzyl)sulfide, in body tissues taken from all the victims, and the concentration of hydrogen sulfide gas at the scene was estimated as having been nearly fatal.

Giant metastatic malignant melanoma with an unknown primary site

We report a case of malignant melanoma of unknown primary origin which presented with a giant metastatic tumor in his right inguinal region. A 94-year-old man noticed a small subcutaneous tumor in the right inguinal region 3 years earlier, which eventually became as larger as 9 cm in diameter without treatment. Although a histological examination of the lesion showed malignant melanoma, extensive examination did not reveal its primary lesion or any metastasis other than that to the right inguinal area. Our case took an interesting course in that this well-growing metastatic tumor was localized in only one region and supported a previous report indicating that malignant melanoma with unknown primary origin has a low tendency to metastasize and a relatively good prognosis.

The use of overlapping and tailed short primers in the chromosomal assignment of short cDNAs by the polymerase chain reaction

For the PCR-based chromosomal assignment of very short cDNA fragments specifically designed primers are required. We tested primers with very short core sequences that are identical or complementary to known cDNA sequences, with or without tails at the 5' ends. The lower limit of the core length for PCR using human chromosome templates was 14 nucleotides (nt) when they have tails. The minimal length of the tail was 2 nt when it was attached to the 5' end of a 14-nt core. In the absence of a tail, 15 nt are needed for the core to act properly. The overall size of the short cDNA fragments that could be assigned was further reduced by using a pair of primers that overlap at the 3' ends. The limits of the free energy of overlap were about -1.9 kcal/mol at 45 degrees C, -2.9 kcal/mol at 50 degrees C and -4.5 kcal/mol at 55 degrees C. A combination of these features in a primer pair allowed cDNA fragments as short as 30 nt to be assigned.

Effect of oxetanocin G, a novel nucleoside analog, on DNA synthesis by hepatitis B virus virions

The novel nucleoside oxetanocin G, 9-(2-deoxy-2-hydroxymethyl-beta-D-erythro-oxetanosyl)guanine (OXT-G), that is a derivative of oxetanocin A, was studied in relation to its action on the synthesis of hepatitis B virus (HBV) DNA and cellular DNA in an HBV-producing cell line, HB611 (T. Tsurimoto, A. Fujiyama, and K. Matsubara, Proc. Natl. Acad. Sci. USA 84:444-448, 1987). The median effective concentration of OXT-G against HBV replication was 1.5 microM, and the median cytotoxic concentration was more than 1,000 microM. At the same concentration, OXT-G did not inhibit cellular DNA synthesis or viral RNA synthesis. Chemically synthesized OXT-GTP inhibited the HBV endogenous DNA polymerase reaction and was incorporated into HBV DNA strands at a low efficiency compared with the incorporation of dGTP. A synthetic primer-template study revealed that OXT-GTP was incorporated into DNA strands at a low efficiency and that further extension of the DNA strand by using the 2' position of the incorporated OXT-G could take place.

A new three-dimensional culture system for hepatocytes using reticulated polyurethane

Poly-N-para-vinylbenzyl-lactonamide (PVLA)-coated reticulated polyurethane (PVLA-RPU) has been employed for the long-term maintenance of primary rat hepatocyte cultures. After 3 days of incubation of 2 x 10(7) hepatocytes/cm3 embedded in PVLA-RPU discs and kept in culture medium, most cells showed typical hepatocyte morphology, with some bile canaliculus-like intercellular spaces among the hepatocytes on examination with scanning and transmission electron microscopy. The cells were attached to the surface of the PVLA-RPU and formed multicellular spheroids in the reticulated pores. The hepatocytes maintained various liver-specific functions such as albumin secretion, ammonium metabolism, urea synthesis and gluconeogenesis, and they were viable. The liver-specific functions could be maintained for more than 1 month when the cells were kept in the rats' peritoneal cavities. This new system may be useful as a bioreactor for an artificial liver.

Hemodynamic parameters during dynamic exercise in patients with silent myocardial ischemia in the presence or absence of hypertrophy

Hemodynamic parameters during supine leg exercise-induced myocardial ischemia were investigated in ten patients without left ventricular hypertrophy (group I), and in ten patients with left ventricular hypertrophy (group II). Both groups of patients had previously been diagnosed as having totally asymptomatic silent myocardial ischemia. Both groups were comparable in age, sex, left ventricular ejection fraction at rest, and extent of coronary artery disease. All of the patients exercised to the same extent without angina or its usual equivalent. Left ventricular filling pressure increased from 4 +/- 2 mmHg at rest to 11 +/- 3 mmHg at peak exercise in group I, and from 7 +/- 4 mmHg at rest to 19 +/- 7 mmHg at peak exercise in group II. Left ventricular filling pressure at peak exercise was significantly greater in group II than in group I (p < 0.01). Totally asymptomatic silent myocardial ischemia can be seen with either normal or mildly abnormal left ventricular filling dynamics during exercise. In addition patients with coexistent left ventricular hypertrophy can have severely abnormal left ventricular filling dynamics during exercise without ischemic cardiac pains. Therefore, severe ischemia and/or stretching of the ventricular wall may be necessary, but not sufficient, for the occurrence of chest pain.

Identification of an active gene by using large-scale cDNA sequencing

A 3'-directed partial cDNA clone that matches exactly a genomic sequence in GenBank was isolated while collecting transcribed sequences from adult lung by a random approach. This is the first report of active gene identification on genomic sequence without the aid of Northern hybridization.

A human cDNA sequence homologue of bovine phosphatidylethanolamine-binding protein

Sequencing of about 1000 3'-directed cDNA clones from the human HepG2 cell line revealed that about half of them represent transcripts of abundantly or moderately expressed genes, about 70% of which are novel. We identified one of these clones as encoding the human homologue of bovine phosphatidylethanolamine-binding protein.