Evaluation of peri-infarcted hypoperfusion with T2*-weighted dynamic MRI

The purpose of this study was to evaluate cerebral perfusion with T2*-weighted dynamic MRI in the area around the infarcted core. We examined seven patients with subacute cerebral infarction. After bolus injection a gadopentetate dimeglumine, a series of gradient-echo images were recorded in a selected slice. From these images, concentration-time curves were created on a region-of-interest (ROI) basis around infarction for calculating relative regional cerebral blood volume (rrCBV). Brain perfusion single photon emission computed tomography (SPECT) study also was performed with intravenous injection of 123I-labeled N-isopropyl-p-iodoamphetamine (123I-IMP). All patients showed prolonged signal decrease in the area around the infarcted core. ROI analysis showed significantly increased rrCBV compared to the normal side (P < .01, paired t test). The 123I-IMP SPECT study showed that these areas had decreased cerebral blood flow. Theses findings suggest compensatory vascular dilatation due to decreased perfusion pressure. T2*-weighted dynamic MRI is a useful method for detecting compensatory vasodilatation of ischemic insult in the peri-infarcted area.

Pharmacological profile of valsartan, a non-peptide angiotensin II type 1 receptor antagonist. 1st communication: antihypertensive effects of valsartan in hypertensive models

The antihypertensive effects of valsartan ((S)-N-valeryl-N-¿[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl¿ valine, CAS 137862-53-4, CGP 48933), an angiotensin II type 1 receptor antagonist, were examined in hypertensive rats and dogs. In normotensive rats and deoxycorticosterone acetate (DOCA)/salt hypertensive rats, valsartan had no effect on blood pressure. Single oral administrations of valsartan at doses of 3-30 mg/kg reduced blood pressure dose-dependently in renal (2 kidney 1 clip, 2K1C) hypertensive and spontaneously hypertensive rats (SHR). Repeated oral administrations of valsartan to these hypertensive rats controlled blood pressure throughout a treatment period of 4 weeks, and showed no rebound phenomenon following drug withdrawal. This drug at 30 mg/kg p.o. decreased blood pressure in renal (2K1C) hypertensive dogs by single and repeated administrations. The extent and duration of the hypotensive action of valsartan were similar to those of enalapril. Valsartan would thus appear as useful as enalapril.

Alterations of lactate (+lipid) concentration in brain tumors with in vivo hydrogen magnetic resonance spectroscopy during radiotherapy

RATIONALE AND OBJECTIVES

The authors determine whether assessment of the relative lactate(+lipid) concentration ([r-Lac(+lip)]) obtained from hydrogen magnetic resonance (MR) spectroscopy is useful for predicting the outcome of radiotherapy on brain tumors.

METHODS

Fifty-one hydrogen MR spectroscopic studies were performed in eight patients with primary or metastatic brain tumor before and during radiotherapy. The r-Lac(+lip) calculated as the ratio of lactate(+lipid) peak area to total water was compared before and during radiotherapy in each case. The change of tumor volume measured on magnetic resonance images also was compared.

RESULTS

The r-Lac(+lip) substantially decreased in the radiosensitive cases (three lymphomas and one brain cancer) but did not decrease, even at the end of therapy, in the radioresistant cases (two brain cancers and two glioblastomas).

CONCLUSION

Assessment of r-Lac(+lip) may adjunctively contribute to the early prediction of the radiotherapeutic effect on brain tumors.

Expression of costimulatory molecules B7-1 (CD80) and B7-2 (CD86) on human hepatocellular carcinoma

Costimulation mediated by costimulatory molecules, such as B7-1 and B7-2, which are ligands for the CD28/cytolytic T lymphocyte associated antigen (CTLA)-4 counter-receptor, plays an important role in the induction of T cell-mediated antitumor immunity. We investigated the expressions of B7-1, B7-2, and human leukocyte antigen (HLA) class I in seven human hepatocellular carcinoma (HCC) cell lines by reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometric analysis. RT-PCR showed that all these human HCC cell lines were positive for B7-1 and B7-2 at the messenger RNA (mRNA) level. Flow cytometric analysis revealed that they all expressed B7-1, B7-2, and HLA class I on the cell surface. However, the expression levels of B7-1 and B7-2 were very low whereas those of HLA class I were high. B7-1 and B7-2 expression could be increased by treatment with interferon alpha and interferon gamma in a dose-dependent manner, although the expression levels of B7-1 and B7-2 after interferon treatment remained low. By transfecting Hep3B cells with a plasmid containing human B7-1 complementary cDNA (cDNA), we were able to establish Hep3B cell lines strongly expressing B7-1. From mixed lymphocytes and tumor cultures analysis, the primary cytolytic activity against parental Hep3B cells could be induced effectively by B71-transfected Hep3B cells. These findings suggested that B7-1 gene transfer is the best way to induce strong expression of this molecule and this might be useful for immuno-gene therapy against human HCC.

Pharmacological profile of valsartan, a non-peptide angiotensin II type 1 receptor antagonist. 3rd communication: hemodynamic effects of valsartan in rats and dogs

Valsartan ((S)-N-valeryl-N-¿[2'-(1H-tetrazol-5-yl)biphenyl-4-yl)methyl¿ valine, CAS 137862-53-4, CGP 48933) at 10 and 30 mg/kg p.o. significantly inhibited angiotensin I and angiotensin II-induced pressor response at 1-8 h after administration in normotensive conscious dogs, but had no effect on blood pressure, heart rate or cardiac functions such as cardiac output, left ventricular pressure, left ventricular max. dP/dt and left ventricular end-diastolic pressure. In contrast to enalapril, this drug did not potentiate bradykinin-induced depressor response. In anesthetized dogs, valsartan at 10 mg/kg i.v. significantly increased renal blood flow, urinary sodium and chloride excretion and urine volume and significantly decreased renal vascular resistance and filtration fraction without affecting blood pressure. The preferential effects on renal hemodynamics were confirmed by the increase in blood flow into the kidneys of spontaneously hypertensive rats at 3 h following oral administration.

Pharmacological profile of valsartan, a non-peptide angiotensin II type 1 receptor antagonist. 4th communication: improvement of heart failure of rats with myocardial infarction by valasartan

The hemodynamic effects of valsartan ((S)-N-valeryl-N-¿[2'-(1H-tetrazol-5-yl)bipheneoyl-4-yl]meth yl¿valine, CAS 137862-53-4, CGP 48933), a new angiotensin II type 1 receptor antagonist, on rats with myocardial infarction induced by coronary artery ligation was examined. Four weeks after ligation, mean blood pressure, left ventricular pressure and cardiac output decreased, while left ventricular end-diastolic pressure increased in control rats. Left ventricular end-diastolic pressure significantly decreased in rats treated with valsartan at 30 mg/kg/d p.o. for 4 weeks. Total systemic resistance remarkably decreased in those with enalapril 3 mg/kg/d p.o. and valsartan 30 mg/kg/d p.o. Valsartan and enalaprilat did not affect cardiac functions of isolated intact rat hearts before and after ischemia in Langendorff apparatus. In addition to hemodynamic effects observed in vivo, valsartan at 30 mg/kg p.o. significantly inhibited left ventricular hypertrophy. Valsartan would thus appear to be clinically useful for treating heart failure following myocardial infarction.

[Apoptosis in human diseases: role of Fas system in liver cell injury by viral hepatitis]

Hepatitis C virus (HCV) and hepatitis B virus (HBV) are major causative agents of chronic liver disease. However, the mechanisms responsible for liver cell injury remain to be clarified. Cytotoxic T lymphocytes play a crucial role in liver cell injury by HCV or HBV infection. Recently, perforin and Fas ligand have been shown to be the only molecules causing T cell-mediated cytotoxicity in short term assays. Therefore, we examined the implication of the Fas system-mediated apoptosis in the liver cell injury. When examined by immunohistochemical method, Fas antigen expression in chronic hepatitis C or B was upregulated in accordance with the severity of liver inflammation. Furthermore, Fas ligand expression was detected in liver-infiltrating mononuclear cells obtained from patients with chronic hepatitis C. These observations suggest that the Fas system plays a dominant role in liver cell injury by viral hepatitis.

Pharmacological profile of valsartan, a non-peptide angiotensin II type 1 receptor antagonist. 2nd communication: valsartan prevents end-organ damage in spontaneously hypertensive stroke-prone rats during 1-year treatment

Valsartan ((S)-N-valeryl-N-¿[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl¿ valine, CAS 137862-53-4, CGP 48933), a non-peptide angiotensin II type 1 receptor antagonist, or enalapril was administered to spontaneously hypertensive rats stroke-prone (SHR-SP) for 1 year from 8 weeks to 56 weeks of age under a normal diet without saline load. During 48 weeks, control rats showed increase in systolic blood pressure from 180 to 250 mmHg accompanying stroke-related behaviour, cardiac and aortic hypertrophy, hyperreactive contractility of mesenteric vascular beds, proteinuria, high water turnover and death. Valsartan at 3, 10 and 30 mg/kg/d p.o. and enalapril at 1 and 10 mg/kg/d p.o suppressed the increase in blood pressure dose-dependently. Systolic blood pressure was steadily controlled to around 180 mmHg at the highest dose of either drug throughout the study. In proportion to the antihypertensive action of the drugs, end-organ damage was prevented. During 1-year administration, effects of enalapril and valsartan were much the same, indicating the clinical usefulness of valsartan being comparable to enalapril.

Hepatitis C virus replicative levels and efficiency of genotyping by specific PCR and antibody assay

We studied factors which influence the detection of hepatitis C virus genotypes by the group-specific PCR of the sequence within the core region gene and by the newly developed genotype-specific NS4 antibody assay. Genotyping was performed on 75 hepatitis C virus carriers in Japan, where patients with hepatitis C viremia are exclusively infected with genotype 1b, 2a, and 2b. PCR failed to identify genotypes in 8 (11%) patients, whereas 12 (16%) patients, including the 8 patients mentioned above, could not be genotyped by the serological assay. Serological genotypes showed almost complete agreement with those found by the PCR except that double infection was revealed in only two of the eight patients serologically judged to be coinfected with genotypes 1 and 2. In each assay, disease activity and levels of viremia assessed by a competitive reverse transcription PCR assay were significantly lower in patients infected with untypeable isolates than in those infected with typeable ones (P < 0.01). The PCR could identify the genotypes of isolates from all 64 patients with levels of viremia of > or = 10(6) copies/ml, and the genotype-specific antibody responses were found in 60 (94%) patients. In contrast, isolates from only 3 (27%) of 11 patients with low levels of viremia (< 10(6) copies/ml) could be genotyped by the PCR (P < 0.00001), and these patients showed the genotype-specific antibody responses (P < 0.00001). These findings suggest that low levels of hepatitis C virus replication may reduce the efficiency of genotyping by serological assay as well as by PCR.

Embryological fusion between the ducts of the ventral and dorsal primordia of the pancreas occurs in two manners

The junction between the main pancreatic duct and the accessory duct has been thought to be the site of fusion between the ducts of the ventral and the dorsal primordia of the pancreas. The aim of this study was to investigate the fusion point between the ventral and the dorsal pancreatic ducts and to determine whether there is any relationship between the configuration of the pancreatic ducts and the manner of embryological fusion. Pancreatography was performed at 22 consecutive autopsies. Immunohistochemical staining of pancreatic polypeptide (PP) was performed because PP cells were rich in the ventral pancreas but poor in the dorsal pancreas. We identified two types of fusion. In one type, the ventral and the dorsal pancreatic ducts fuse at their junction (one-point fusion). In the other type, the two ducts fuse not only at the proximal site but at a second, more distal site (two-point fusion). Analysis of the pancreatograms showed that the distance between the junction and the major papilla in two-point fusion is significantly shorter than in one-point fusion (p < 0.01). These results indicate a close correlation between the pattern seen on pancreatograms and the manner of embryological fusion.

A novel therapeutic approach for rectal varices: a case report of rectal varices treated with double balloon-occluded embolotherapy

We present a patient with continuous melena, diagnosed as rectal varices bleeding. She had a history of esophageal varices, which was treated by endoscopic ligation therapy. Eight years after the treatment of esophageal varices, the continuous melena began. Colonoscopic examination showed that the melena was caused by rectal varices, which were so severe that they could not be treated by either endoscopic sclerotherapy or surgical devascularization. Taking into considering the overall risk of treating rectal varices, we chose the approach of double balloon-occluded embolotherapy (DBOE) with 5% ethanolamine oleate with iopamodol as a liquid embolic material. DBOE is one of the interventional radiology techniques (Morita et al., Acta Hepatol Jpn 1994;35:109-120), but in this case was a completely new and novel clinical procedure for rectal varices. After the DBOE therapy, the condition of rectal varices was markedly improved. Thus, DBOE might be a new tool for treating inoperable rectal varices.

Pharmacological profile of valsartan, a non-peptide angiotensin II type 1 receptor antagonist. 5th communication: hemodynamic effects of valsartan in dog heart failure models

Hemodynamic effects of valsartan ((S)-N-valeryl-N-¿[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]meth yl¿valine, CAS 137862-53-4, CGP 48933), a non-peptide angiotensin II type 1 receptor antagonist were examined in dogs with heart failure induced acutely by coronary artery ligation and chronically by rapid-ventricular pacing. Coronary artery ligation induced decrease in cardiac output and increase in left ventricular end-diastolic pressure. Valsartan at 10 mg/kg i.v. reduced blood pressure, heart rate, left ventricular pressure, left ventricular end-diastolic pressure and total systemic resistance. Similar changes were observed with enalaprilat at 0.1 mg/kg i.v. Rapid left ventricular pacing for 2 weeks reduced cardiac contractility. Valsartan, administered at a dose of 100 mg/kg/d p.o. for 2 weeks, lowered left ventricular end-diastolic pressure. Valsartan reduced preload and afterload in these two dog heart failure models.

GATA-1 transcription is controlled by distinct regulatory mechanisms during primitive and definitive erythropoiesis

Transcription factor GATA-1 is required for the terminal differentiation of both the primitive and definitive erythroid cell lineages, and yet the regulatory mechanisms of GATA-1 itself are not well understood. To clarify how the GATA-1 gene is transcriptionally controlled in vivo, presumptive regulatory regions of the gene were tested by fusion to a reporter gene and then examined in transgenic mice. We found that a transcriptional control element located between -3.9 and -2.6 kb 5' to the erythroid first exon serves as an activating element and that this sequence alone is sufficient to recapitulate the expression of GATA-1 (but uniquely in primitive erythroid cells). Addition of sequences from the GATA-1 first intron to this upstream element provides a necessary and sufficient condition for complete recapitulation of GATA-1 expression in both primitive and definitive erythroid cells. The first intron element does not possess intrinsic transcriptional activation potential when linked to the GATA-1 gene promoter but rather requires the upstream activating element for its activity. These experiments show that GATA-1 gene expression is regulated by discrete transcriptional control elements during definitive and primitive erythropoiesis: The 5' element displays properties anticipated for a primitive erythroid cell-specific activating element, and the novel element within the GATA-1 first intron specifically augments this activity in definitive erythroid cells.

Involvement of the transcriptional factor GATA-1 in regulation of expression of coproporphyrinogen oxidase in mouse erythroleukemia cells

Coproporphyrinogen oxidase (CPO; EC 1.3.3.3), the sixth enzyme of heme biosynthesis, transcribed from a single promoter is markedly induced during erythroid differentiation. CPO is ubiquitously expressed in all cells. To determine cis-acting elements of the human CPO gene, the promoter region of the gene was isolated, and three potential GATA-1 motifs and four GC boxes were found within this fragment. In a functional analysis of various deletion mutants, we found that the GATA-1 binding site at -143 to -138 was essential for basic and inducible expressions of the CPO gene in mouse erythroleukemia (MEL) cells. Gel mobility shift assay revealed that GATA-1 bound to the region is required for the expression and this was confirmed by observations that the nuclear protein bound to the GATA-1 motif was supershifted with anti GATA-1 antibody, by gel mobility shift assay. Furthermore, co-expression of mouse GATA-1 in MEL cells led to an increase in the promoter activity, which was markedly increased by dimethyl sulfoxide-treatment. These results indicate that GATA-1 plays an important role in regulation of transcription of the CPO gene in erythroid cells.

Yrb2p, a Nup2p-related yeast protein, has a functional overlap with Rna1p, a yeast Ran-GTPase-activating protein

The Ran-GTPase cycle is important for nucleus-cytosol exchange of macromolecules and other nuclear processes. We employed the two-hybrid method to identify proteins interacting with Ran and the Ran GTP/GDP exchange factor. Using PRP20, encoding the Ran GTP/GDP exchange factor, we identified YRB1, previously identified as a protein able to interact with human Ran GTP/GDP exchange factor RCC1 in the two-hybrid system. Using GSP1, encoding the yeast Ran, as bait, we isolated YRB2. YRB2 encodes a protein containing a Ran-binding motif similar to that found in Yrb1p and Nup2p. Yrb1p is located in the cytosol whereas Nup2p is nuclear. Similar to Yrb1p, Yrb2p bound to GTP-Gsp1p but not to GDP-Gsp1p and enhanced the GTPase-activating activity of Rna1p. However, unlike Yrb1p, Yrb2p did not inhibit the nucleotide-releasing activity of Prp20p. While overproduction of Yrb1p inhibited the growth of a mutant possessing a PRP20 mutation (srm1-1) and suppressed the rna1-1 mutation, overproduction of Yrb2p showed no effect on the growth of these mutants. Disruption of YRB2 made yeast cold sensitive and was synthetically lethal with rna1-1 but not with nup2delta. Nuclear protein import and the mRNA export were normal in strains possessing mutations of YRB2. We propose that Yrb2p is involved in the nuclear processes of the Ran-GTPase cycle which are not related to nucleus-cytosol exchange of macromolecules.

Tumor neutrophil elastase is closely associated with the direct extension of non-small cell lung cancer into the aorta

OBJECTIVE

Neutrophil elastase (NE) is the only neutral protease that is able to degrade insoluble elastin and other extracellular matrix constituents, and thus, may be involved in tumor invasion and metastasis. Using a highly specific and sensitive enzyme immunoassay (EIA), we recently demonstrated that immunoreactive (ir)-NE is produced by non-small cell lung cancer cell lines. We have measured the ir-NE concentration in non-small cell lung cancer tumor extracts and have evaluated its association with disease stage.

METHODS

We measured the ir-NE concentration in 144 non-small cell lung cancer tumor extracts using EIA, which permits the rapid measurement of both the free and alpha1-protease inhibitor (alpha1-PI) complexed form of ir-NE. In 15 clinical T4 (cT4) patients, we also determined the concentration of free ir-NE in tumor extracts using a kit that detects only NE complexed with alpha1-PI and subtracting that value from the total NE concentration.

RESULTS

ir-NE was detected in tumor extracts from 115 of 144 patients, ranging from 0.21 to 23.35 microg/100 mg protein. When the 144 specimens were grouped according to the clinical stage of disease, the ir-NE concentration (mean+/-SE) was significantly higher in those with cT4 disease (n=15; 7.90+/-1.88 microg/100 mg protein) than in those with cT1 (n=29; 1.27+/-0.27; p<0.001), cT2 (n=64; 1.18+/-0.17; p<0.001), or cT3 disease (n=26; 1.99+/-0.38; p<0.003). There was no significant association between the ir-NE concentration and cN-factor or any other clinical features. When the ir-NE concentration in the tumor extracts of the cT4 patients was compared with respect to the tumor invasion sites, the ir-NE level was significantly higher in those with surgical T4 (sT4) disease with aortic invasion (n=4; 17.4+/-3.10) than in those who were down-staged postoperatively (n=5; 4.9+/-1.33; p=0.005) or those with sT4 disease with involvement of other sites (n=6; 4.07+/-1.83; p=0.004). Similar results were observed for the free form of ir-NE.

CONCLUSIONS

These data suggest that NE may be involved in tumor progression of non-small cell lung cancer. Since the aorta is one of the richest sources of polymeric and insoluble elastin, this enzyme may play an active role in the direct extension of the tumor into the aorta.

Evaluation of combined therapy with chemoembolization and ethanol injection for advanced hepatocellular carcinoma

To evaluate the therapeutic efficacy of transcatheter arterial chemoembolization (TACE) combined with percutaneous ethanol injection therapy (PEIT) for advanced hepatocellular carcinoma, we studied the effectiveness of TACE therapy combined with PEIT (50 cases) and TACE alone (50 cases). In both groups, patients had multiple lesions, or a single lesion with a diameter exceeding 2 cm or with vascular invasion (stages II, III, and IV in the tumor staging classification of the Liver Cancer Study Group of Japan). The clinical features in the two groups were comparable. The cumulative survival rates with TACE-PEIT were 95.0% for 1 year, 72.5% for 2 years, and 50.0% for 3 years, whereas the rates with TACE alone were 92.5% for 1 year, 57.5% for 2 years, and 20.0% for 3 years. The survival rate in the TACE-PEIT group was significantly higher than that in the TACE alone group. Moreover, the survival rate of patients with stage II or III disease in the TACE-PEIT group was significantly better than that in the TACE alone group, and the survival rate of patients with Child's classification B or C in the TACE-PEIT group was significantly higher than that in the TACE alone group. Multivariate analysis using Cox's proportional hazard regression model showed that the most significant prognostic factors in the TACE-PEIT group were tumor embolus in the portal vein and the number of tumors. These results suggest the effectiveness of combining TACE and PEIT for the treatment of advanced hepatocellular carcinoma.

Expression of GATA transcription factors in myelogenous and lymphoblastic leukemia cells

In the hematopoietic lineage, the transcription factors GATA-1 and GATA-2 show restricted and largely overlapping expression profiles, but GATA-2 is uniquely expressed in early hematopoietic progenitors. GATA-3 is found exclusively in T cells of hematopoietic lineage. To clarify whether these expression profiles are preserved or changed during the development of malignancies, we analyzed the expression of GATA factors in the blasts from leukemic children. A total of 18 myelogenous leukemia and 24 lymphoblastic leukemia (ALL) cases were investigated. In the majority of the former cases, GATA-2 mRNA expression and the expression of CD34 and c-kit antigens on leukemic cells were demonstrated. In contrast, GATA-2 mRNA and c-kit antigen could not be detected in CD34-positive cells from ALL patients. GATA-3 mRNA was expressed in all T-ALL cases, but not in any precursor B-ALL. These findings suggest that down-regulation of GATA-2 and expression of GATA-3 are important events for the commitment of cells to lymphoid and T cell lineage, respectively. The expression profiles of GATA factors in leukemic cells are generally consistent with those in their normal counterparts, and thus provide a useful tool to determine the lineage commitment of unclassified leukemia.

[Angiography by scanning laser ophthalmoscope with fluorescein compounds of different physicochemical properties]

We performed angiography in photocoagulated eyes using four fluorescent dyes that have different molecular weight, lipid solubility, and electric charge. These findings were compared with those of sodium fluorescein (Naf) and indocyanine green (ICG). Angiograms were obtained with Naf, ICG and two fluorescein isothiocyanate dextrans at different molecular weight (FITC-D4: MW 4,400, FITC-D40: MW 38,900). We also used two other dyes: carboxyfluorescein (Caf: less lipid soluble) and calcein (Calc: a highly negatively charged molecule). Two and four days after laser photocoagulation of retina, dye leakage was still evident at the photocoagulated sites with Naf, Caf, Calc and FITC-D4. Angiograms taken after Caf and Calc injection showed more intense and rapid dye leakage than with Naf. Contrary to this, little dye leakage was observed with ICG and FITC-D40. These findings indicated that the critical molecular weight for permeation lay between 4,400 and 38,900 once the breakdown of blood retinal barrier occurred. In addition, difference in molecular weight is a major factor determining dye permeability at the photocoagulated retinal lesions, among other possibilities such as lipid solubility and electric charge.

Antibody responses to the hepatitis C virus E2 protein: relationship to viraemia and prevalence in anti-HCV seronegative subjects

A small proportion of patients with chronic hepatitis C virus (HCV) infection show no serological responses to the HCV polypeptides incorporated in commercial III generation immunoassays. To determine whether sera from these subjects contain antibodies to the highly immunoreactive second envelope polypeptide E2, which is not included in current anti-HCV assays, we studied 59 anti-HCV negative subjects who were found consistently to be HCV RNA positive by polymerase chain reaction (PCR). Controls included 167 anti-HCV seropositive patients with or without serum HCV RNA and normal subjects. Antibodies to the E2 region were sought for by ELISA using the following antigens: a full length E2 protein expressed in insect cells using a baculovirus vector and extracted under denaturing conditions (dE2), and a C-terminal truncated soluble E2 (sE2) protein (a.a. 390-683), also expressed with a baculovirus vector, containing a signal peptide of rabies virus G protein which allows its secretion into the culture supernatant. Sera from only two (3.4%) of the 59 anti-HCV negative, HCV RNA positive patients recognised sE2 and none dE2. In sharp contrast, 82% of seropositive, viraemic patients recognised sE2 and 60% dE2, the difference in immunoreactivity being statistically significant (P < 0.0003). A significantly lower proportion of sera from anti-HCV positive, HCV RNA negative subjects recognised either sE2 or dE2 (16% and 13%, respectively, P < 0.000001). Healthy controls were consistently negative. These results indicate that antibody responses to predominantly conformational epitopes on the HCV E2 protein are common in patients with chronic HCV infection and are strictly related to the presence of circulating viral genomes. In contrast, only a minor proportion of HCV RNA positive patients, but anti-HCV seronegative by commercial immunoassays, have humoral immune responses to the HCV E2 region.

Circular dichroism and 1H nuclear magnetic resonance studies on the solution and membrane structures of GAP-43 calmodulin-binding domain

Growth-associated protein-43 (GAP-43) is believed to be palmitoylated near the N terminus and the modification is assumed to be involved in the membrane anchoring of the protein. However, GAP-43 isolated from bovine brain is not palmitoylated as shown by mass spectrometric analysis, but still retains the ability to bind phospholipids, suggesting that other parts of the molecule are involved in the interaction. Upon addition of acidic phospholipids, purified GAP-43 showed a conformational change from random coil to alpha-helix as indicated by a change in CD spectra. A synthetic peptide corresponding to the calmodulin-binding domain showed a similar conformational change from random coil to alpha-helix in the presence of various acidic phospholipids. These results suggest that the calmodulin-binding domain of GAP-43 is directly involved in the GAP-43-membrane interaction and undergoes a conformational change upon binding to phospholipid membranes. After phosphorylation by protein kinase C, the phospholipid-induced conformational changes were no longer observed. Structural characteristics of the calmodulin-binding domain peptide in aqueous and hydrophobic solvents were further studied in detail by two-dimensional 1H nuclear magnetic resonance. The results obtained suggest that the domain assumes a nascent alpha-helical structure in aqueous solution, which is stabilized under hydrophobic environments.

Novel regulation of delta-aminolevulinate synthase in the rat harderian gland

The mode of expression of delta-aminolevulinate synthase (ALAS), as well as that of mRNAs for other heme pathway enzymes, was examined in the rat Harderian gland. Northern blot and in situ hybridization analyses demonstrated that the non-specific ALAS (ALAS-N) mRNA is highly expressed in this tissue, whereas the erythroid-specific ALAS (ALAS-E) mRNA is not. Immunoblot analysis of ALAS also confirmed this finding at the protein level. ALAS-N mRNA was maximally induced in the Harderian gland and was not increased further by treatment of animals with 2-allyl-2-isopropylacetamide (AIA). The levels of mRNAs for other heme pathway enzymes, i.e., delta-aminolevulinate dehydratase, porphobilinogen deaminase, uroporphyrinogen decarboxylase, and coproporphyrinogen oxidase, also were increased markedly in the Harderian gland and not influenced by AIA treatment. The level of ferrochelatase (FeC) mRNA in the gland was, however, lower than that in the liver. The gland contained an extremely high level of protoporphyrin, while heme was undetectable. Microsomal heme oxygenase-1 (HO-1) mRNA levels were significantly higher in the Harderian gland than in the liver. When isolated glands were incubated with hemin in vitro in organ cultures, the level of HO-1 mRNA was increased, whereas the ALAS-N mRNA level was not. These findings indicate that markedly elevated levels of protoporphyrin and extremely low levels of heme in the Harderian gland are the results of both decreased expression of FeC and markedly increased expression of ALAS-N and HO-1. The constitutive expression of the ALAS-N gene in the Harderian gland suggests a novel transcriptional control mechanism of this gene.

[HGV is rare but possible causative agent of non-A non-B fulminant hepatitis]

We analyzed HBV, HCV and HGV using PCR amplification in the 19 fulminant patients with unknown etiology. Three patients(15.8%) had HCV alone and 1(5.2%) was coinfected with HCV and HGV. In all cases, the possibility of contamination of these viral agent through blood transfusion was excluded. HBV was undetectable in the present study. Comparative analysis revealed that in the cases with HCV alone, all patients showed slow progression. On the other hand, the coinfected case rapidly developed into the end stage of hepatic failure. These results demonstrated that the prevalence of HGV in the fulminant hepatitis was rare in Japan. However, there is a possibility that HGV may modify the clinical course of HCV-induced fulminant hepatitis.

B7/BB-1 expression and hepatitis activity in liver tissues of patients with chronic hepatitis C

Cytotoxic T lymphocytes (CTL) are closely related to the mechanism of liver injury in chronic viral hepatitis. Recently, it has been suggested that antigen-specific T cell activation requires both presentation of antigen by major histocompatibility complex (MHC) molecules and the delivery of costimulatory signals. Such signals are provided by B7/BB-1, one of the most important accessory molecules, sufficient for causing antigen-specific MHC-restricted T cell activation. To evaluate the role of B7/BB-1 in chronic hepatitis C, we immunohistochemically studied its expression in liver tissues obtained from 61 patients with hepatitis C virus (HCV) infection and compared them based on hepatitis activity. In HCV-infected liver, B7/BB-1 was strongly expressed in the cytoplasm of hepatocytes. B7/BB-1-positive cells accompanied liver-infiltrating lymphocytes and were mainly detected in the periportal region. B7/BB-1 expression was closely correlated with the activity of viral hepatitis as evaluated from scores of periportal or intralobular inflammation and necrosis, or serum alanine transferase (ALT) levels. Further study by immunostaining with anti-HCV core and anti-human leukocyte antigen (HLA) class I antibody showed B7/BB-1 positive cells near HCV core antigen- and HLA class I-positive cells, with B7/BB-1-positive cells mostly included among HLA class I-positive cells. These findings suggested that B7/BB-1 expression by hepatocytes may be induced by HCV infection and may trigger generation and activation of CTL, which may cause damage to HCV-infected HLA class I-expressing hepatocytes.