Gamma-ray induced hepatocarcinogenesis in p53-deficient mice

BACKGROUND

Mutations in the p53 gene are frequent genetic alterations in human hepatocellular carcinoma (HCC), but, little is known of the molecular genetic changes that occur during murine hepatocarcinogenesis.

MATERIALS AND METHODS

To characterize the properties of constitutive p53 deficiency that contribute to liver tumor development, a total of 168 F1 mice of two different strains (C3H, which are susceptible to hepatocarcinogenesis and MSM [Mus. M. molossinus] with a single null p53 allele) were exposed to a single 3-Gy dose of whole-body gamma-irradiation at 4 weeks of age and observed for a period of 360 days. The genotype of the mice and the p53 spectrum of the tumors were investigated by polymerase chain reaction (PCR) analysis.

RESULTS

Thirty-five gamma-ray-induced HCCs were obtained as a result of this experiment. 11 (40%) of the mice with liver tumor were wild-type for p53. All liver tumors examined retained the wild-type p53 allele, indicating that p53 itself may not be a target for radiation-induced alteration. Only two p53-deficient mice in the liver tumor group developed thymic lymphomas. The p53-deficient mice showed no significant differences in the number, size, or growth rate of HCC or in the apparent development of HCC.

CONCLUSION

These results indicate that p53 deficiency does not enhance the rate of development or degree of malignancy of radiation-induced HCC in mice but may instead favor the development of multiple primary cancers.

Expression and regulation of a gene encoding neural recognition molecule NB-3 of the contactin/F3 subgroup in mouse brain

NB-3 is a neural recognition molecule which is a member of contactin/F3 subgroup in the immunoglobulin superfamily. We report here the developmental expression pattern and localization of NB-3 mRNA in mouse brain, determination of the NB-3 gene organization and identification of the promoter region. We also describe a splicing isoform of mouse NB-3. Mouse NB-3 exhibited 96% identity with rat NB-3 at the amino acid sequence level. The splicing isoform lacked the amino acid residues between 62 and 78 of the original NB-3, which constituted a part of the first immunoglobulin-like domain. The expression of NB-3 mRNA was evident after birth, reaching a maximum at the postnatal seventh day, and declined thereafter in the cerebrum, whereas the mRNA increased in the cerebellum to adulthood. In situ hybridization demonstrated that NB-3 mRNA was preferentially expressed in the accessory olfactory bulb, layers II/III and V of the cerebral cortex, piriform cortex, anterior thalamic nuclei, locus coeruleus of the pons and mesencephalic trigeminal nucleus, and in Purkinje cells of the cerebellum. The mouse NB-3 gene consisted of 23 exons spanning more than 130kb. The overall organization of the gene was similar to those of the F11, axonin-1 and TAX-1 genes of the subgroup. By reporter gene analysis with the 5'-flanking region of the gene, we found a basal promoter activity in the 1.2kb fragment upstream of the putative transcription initiation site. This study provides a basis for elucidating the biological significance of the contactin/F3 subgroup molecules.

Cell-cycle regulation of the DNA topoisomerase IIalpha promoter is mediated by proximal CCAAT boxes: possible involvement of acetylation

Expression of DNA topoisomerase (topo) IIalpha is cell-cycle-regulated, with its peak in G(2)/M and its lowest level in G(0)/G(1). In agreement with this expression pattern, we have shown that the topo IIalpha gene promoter shows cell-cycle-dependent activity, which is repressed in G(0)/G(1) and activated exclusively in G(2)/M. However, the promoter sequence reveals no canonical CDE/CHR motifs, repressor elements commonly found in promoters of late S/G(2)-activated genes. Here, we show that at least two of the three proximal inverted CCAAT boxes (ICBs) are responsible for the G(2)/M-specific activation of the topo IIalpha promoter. Using antibody supershift experiments, we identify NF-Y as the ICB-binding transcription factor. However, the expression profile and binding capacity of NF-Y were constant during the cell cycle, suggesting a more global mechanism in topo IIalpha promoter regulation. Interestingly, we find that trichostatin A (TSA), a specific histone deacetylase inhibitor, greatly enhances topo IIalpha promoter activity in an ICB-dependent manner. In addition, the effect of TSA is predominant in G(0)/G(1) and less obvious in G(2)/M. Our data, along with the recent findings that NF-Y associates in vivo with histone acetyltransferases (HATs), strongly suggest a mechanism, in which histone deacetylation plays a crucial role in the G(0)/G(1)-specific repression of the topo IIalpha promoter, and NF-Y recruits HATs to the promoter region, thereby stimulating histone acetylation and activating transcription in G(2)/M.

Effect of shitei-to, a traditional Chinese medicine formulation, on pentylenetetrazol-induced kindling in mice

This study measured the effects of Shitei-To (STT), a traditional Chinese Medicine, which is a mixture of extracts from three medicinal herbs, Shitei (SI, Kaki Calyx; calyx of Diospyros kaki L. f.), Shokyo (SK, Zingiberis Rhizoma; rhizome of Zingiber officinale Roscoe) and Choji (CJ, Caryophylli flos; flowerbud of Syzygium aromaticum [L.] Merrill et. Perry), has long been used for the treatment of hiccups in Japan and China, against fully pentylenetetrazol-kindled seizures and on the development of pentylenetetrazol kindling in mice. Repeated administration of STT (3.0 g/kg p.o.) mildly retards the development of pentylenetetrazol-induced kindling in mice. STT also decreased the number of tonic-clonic convulsions resulting from progression kindling. On the other hand, STT had no effect on convulsions in fully pentylenetetrazol-kindled mice. These findings suggest that STT protects against the development of convulsions, and that STT may have therapeutic effects in the prevention of secondarily generalized seizures.

Structural basis for the regulation of UDP-N-acetyl-alpha-D-galactosamine: polypeptide N-acetylgalactosaminyl transferase-3 gene expression in adenocarcinoma cells

The UDP-N-acetyl-alpha-D-galactosamine: polypeptide N-acetylgalactosaminyl transferase-3 (Gal NAc-T3) gene, a member of the Gal NAc transferase gene family, is expressed in a tissue-specific manner. To elucidate the function of this gene, we have focused on the molecular mechanism underlying regulation of gene expression. We have cloned Gal NAc-T3 cDNA and used it to show that Gal NAc-T3 mRNA is expressed in tumor cell lines derived from secretory epithelial tissue adenocarcinomas but not in cell lines derived from bladder and epidermoid carcinomas. Using a polyclonal antibody to Gal NAc-T3, we observed protein expression in adenocarcinoma but not non-adenocarcinoma cell lines, and in breast carcinoma cells but not in normal breast tissue. We used Gal NAc-T3 cDNA to isolate three overlapping genomic clones containing the 5'-portion of the human Gal NAc-T3 gene, and we sequenced 1.6 kb around the first exon. A transient expression assay using the luciferase gene showed that promoter activity was much higher in MCF-7 cells than in KB cells. In vivo footprint experiments showed significant protection of a distal GC box, an NRF-1 site, and an AP-2 site in MCF-7 cells. A novel stem and loop structure extending from nucleotide -103 to nucleotide -165 and contiguous to these transcription factor binding sites seemed to be functional in regulating Gal NAc-T3 gene transcription, and a KMnO4 footprint experiment showed that this stem and loop structure could be formed in vivo. We also observed dimethyl sulfate hypersensitive sites in the untranslated region around nucleotide +50 in MCF-7 but not in KB cells. These findings indicate that Gal NAc-T3 gene expression is regulated by multiple systems, including transcription factor binding sites and a stem-and-loop structure, and that this regulation is restricted to cell lines derived from epithelial gland adenocarcinomas but not cells derived from nonsecretory epithelial tissue carcinomas. In addition, our immunohistochemical results suggest that our anti-Gal NAc-T3 antibody may be useful for diagnostic purposes in the early stages of breast cancer.

Quantification of neuromodulin (GAP-43, B-50) and synapsin I in rat striata

We reported previously that phosphorylated neuromodulin and phosphorylated synapsin I content increased in the striata of amphetamine-sensitized rats; however, the neuronal pathways responsible for the increase were unclear. In the present study, changes in neuromodulin and synapsin I content resulting from the manipulation of lesions were quantified to elucidate the responsible pathways. Nerve terminals originating in the corticostriatal pathway, those from the nigrostriatal pathway and those from interneurons in the striatum, were impaired by unilateral cortical ablation, 6-hydroxydopamine (6-OHDA) treatment and kainic acid injection into the striatum, respectively. Neuromodulin and synapsin I content in the ipsilateral striatum after unilateral ablation of the frontal cortex decreased by 51 and 31%, respectively. The impairment of dopaminergic terminals by 6-OHDA reduced the neuromodulin content by 22%; however, no significant alteration was observed in the synapsin I content as the result of 6-OHDA treatment. The injection of kainic acid did not cause the content of either protein to decrease. These results suggest that corticostriatal nerve terminals possess a large part of the total neuromodulin and almost all the synapsin I in the striatum. Therefore, the increase in phosphorylated neuromodulin induced by repeated treatment with amphetamine may occur in corticostriatal glutamatergic terminas and/or nigrostriatal dopaminergic terminals. On the other hand, the increase in phosphorylated synapsin I may preferentially occur in the corticostriatal glutamatergic terminals.

Novel patterns of amino acid mutations in the hepatitis B virus polymerase in association with resistance to lamivudine therapy in japanese patients with chronic hepatitis B

Lamivudine is effective in suppressing replication of hepatitis B virus (HBV). However, the emergence of HBV variants resistant to lamivudine is a concern. Lamivudine resistance has been attributed mainly to a substitution of isoleucine or valine for methionine at residue 550 (M550I or M550V) in the catalytic site of the virus polymerase. A substitution of methionine for leucine at residue 526 (L526M) has also been identified. To examine such virus genotypic mutations in Japanese patients, we studied five patients with chronic hepatitis B, who showed HBV breakthrough while on a 1-year lamivudine treatment. The entire nucleotide and deduced amino acid sequences of the proposed reverse transcriptase domain of the polymerase gene were determined on HBV DNA amplified by polymerase chain reaction from patient sera collected at the start and at the end of therapy. The HBV sequences from all five patients were of genotype C. In four patients, a substitution of valine or isoleucine for leucine at residue 426, which has not been reported previously, emerged in combination with M550I. One also harbored L526M. In the remaining patient, an alteration of leucine to methionine at residue 428 co-occurred with M550V. Longitudinal study of the mutations showed that the two or three mutations in each patient emerged almost simultaneously 4 weeks before or at the time of breakthrough and were replaced by wild-type virus after completing the therapy. Our results indicate that occurrence of HBV polymerase mutations at residue 426 in combination with M550I is frequent in Japanese or genotype C virus-in- fected patients who develop resistance to lamivudine.

Novel patterns of amino acid mutations in the hepatitis B virus polymerase in association with resistance to lamivudine therapy in japanese patients with chronic hepatitis B

Lamivudine is effective in suppressing replication of hepatitis B virus (HBV). However, the emergence of HBV variants resistant to lamivudine is a concern. Lamivudine resistance has been attributed mainly to a substitution of isoleucine or valine for methionine at residue 550 (M550I or M550V) in the catalytic site of the virus polymerase. A substitution of methionine for leucine at residue 526 (L526M) has also been identified. To examine such virus genotypic mutations in Japanese patients, we studied five patients with chronic hepatitis B, who showed HBV breakthrough while on a 1-year lamivudine treatment. The entire nucleotide and deduced amino acid sequences of the proposed reverse transcriptase domain of the polymerase gene were determined on HBV DNA amplified by polymerase chain reaction from patient sera collected at the start and at the end of therapy. The HBV sequences from all five patients were of genotype C. In four patients, a substitution of valine or isoleucine for leucine at residue 426, which has not been reported previously, emerged in combination with M550I. One also harbored L526M. In the remaining patient, an alteration of leucine to methionine at residue 428 co-occurred with M550V. Longitudinal study of the mutations showed that the two or three mutations in each patient emerged almost simultaneously 4 weeks before or at the time of breakthrough and were replaced by wild-type virus after completing the therapy. Our results indicate that occurrence of HBV polymerase mutations at residue 426 in combination with M550I is frequent in Japanese or genotype C virus-in- fected patients who develop resistance to lamivudine.

Effects of beta-blockers and nicardipine on oxotremorine-induced tremor in common marmosets

Effects of beta-blockers (propranolol, arotinolol and nipradilol) and a Ca2+ channel blocker (nicardipine) on oxotremorine-induced tremor were studied in common marmosets. Generalized tremor was elicited by an intraperitoneal administration of 0.25 mg/kg oxotremorine. Intensity of the tremor was classified into 7 degrees, and it was evaluated every 10 min. The total intensity of oxotremorine-induced tremor for each drug was expressed as "points", which were the sum of tremor intensity scores evaluated every 10 min up to 190 min following the administration of oxotremorine. Beta-blockers significantly suppressed the tremor. On the other hand, the Ca2+ channel blocker exacerbated the tremor.

Reduction of telomeric repeats as a possible predictor for development of hepatocellular carcinoma: convenient evaluation by slot-blot analysis

Hepatocellular carcinoma (HCC) mainly arises from the liver with chronic inflammation. Because telomere reduction reflects replicative history in somatic cells, we analyzed the possibility that liver tissues surrounding HCC consist of the cells carrying substantial reduction of telomere. We studied 20 HCC and surrounding noncancerous liver tissues (SL) obtained by surgical resection, and 10 laparoscopically obtained needle biopsy specimens of the liver with chronic inflammation including no overt HCC (CI). Five liver tissues without chronic liver diseases (ND) were also examined. Extracted genomic DNAs were blotted on a nylon membrane, and probed at first with radio-labeled d(TTAGGG)(3) and reprobed with radio-labeled d(CCT)(7). The intensity caused by d(TTAGGG)(3) was divided by that of d(CCT)(7). The ratio was defined as telomeric repeats content (TC). Dilution experiments reproducibly revealed almost the same TC. The reduction rate of telomere length through aging estimated by regression analysis of TC was 0.62% per year. Concomitant analyses of TC and average telomere length revealed that both values were significantly correlated (r =.45; P =.009). To compare TC in the liver with respect to chronic inflammation, the value was divided by TC in peripheral blood leukocytes (PBL) from the same donor. The ratio was defined as relative TC (RTC). There was a statistically significant decrease of RTC in CI compared with that in ND (P =.03). Furthermore, RTC in SL was significantly lower than that in CI (P =.0001). These observations suggest that RTC value in liver tissues may digitally indicate a replicative history of hepatocytes under chronic inflammation, and a risk of HCC development.

Sensitization by prolonged glutathione depletion of kainic acid to potentiate DNA binding of the nuclear transcription factor activator protein-1 in murine hippocampus

In four of four mice intracerebroventricularly injected with the inhibitor of glutathione synthesis L-buthionine-[S,R]-sulfoximine (BSO) 2 days before, an intraperitoneal injection of kainic acid (KA) invariably led to marked potentiation of DNA binding activity of the nuclear transcription factor activator protein-I (AP1) in the hippocampus at a dose which was ineffective in animals previously injected with vehicle alone. However, KA failed to potentiate binding in animals injected with BSO 1 day before. The intracerebroventricular injection of BSO induced marked and prolonged depletion of a total glutathione content in murine hippocampus for 1-2 days after administration. These results suggest that prolonged depletion of endogenous glutathione for a period longer than 1 day may lead to sensitization of KA signals to potentiate AP1 DNA binding in cell nuclei and thereby modulate de novo synthesis of particular proteins at the level of gene transcription in murine hippocampus.

T-Cell hyporesponsiveness induced by activated macrophages through nitric oxide production in mice infected with Mycobacterium tuberculosis

In active tuberculosis, T-cell response to Mycobacterium tuberculosis is known to be reduced. In the course of Mycobacterium tuberculosis infection in mice, we observed that T-cell proliferation in response to M. tuberculosis purified protein derivative (PPD) reached the maximum level on day 7, then declined to the minimal level on day 14, and persisted at a low level through day 28 postinfection. The frequency of PPD-specific CD4 T cells in the spleen on day 28 decreased to one-sixth on day 7. To further investigate the mechanism of this T-cell hyporesponsiveness, we next analyzed the suppressive activity of spleen macrophages on T-cell function. The nonspecific proliferative response of naive T cells and the PPD-specific proliferative response of T cells were suppressed by day 28 macrophages, but not by day 7 macrophages or naive macrophages. This reduction of proliferative response was restored by addition of nitric oxide synthesis inhibitor, NG-monoethyl-L-arginine monoacetate, but not by monoclonal antibody against interleukin 10 or transforming growth factor beta. These data indicate that the macrophages from mice chronically infected with M. tuberculosis suppress T-cell response through production of nitric oxide, suggesting that nitric oxide-induced elimination mediated by activated macrophages may reduce the T-cell response and the number of mycobacterium-specific CD4 T cells in vivo.

Efficacy of shitei-to, a traditional Chinese medicine formulation, against convulsions in mice

The anticonvulsant effects of Shitei-To and its components on maximal electroshock seizures and chemical convulsions were examined. Shitei-To significantly prolonged the latency to bicuculline (2.0 mg/kg, s.c.)-induced clonic convulsions. Repeated treatment with Shitei-To also significantly prolonged the latency to strychnine (1.5 mg/kg, i.p.)- and pentylenetetrazol (90 mg/kg, i.p.)-induced clonic convulsions. On the other hand, Shitei-To had no effect on maximal electroshock seizures. Of the components of Shitei-To, Shitei had almost the same effect as Shitei-To against the clonic convulsions induced by the three chemical agents tested. These findings suggest that Shitei-To has anticonvulsant effects.

Effect of diesel exhaust on guinea pig nasal mucosa

In this study using guinea pigs, we investigated the effects of diesel exhaust (DE) containing diesel exhaust particulate (DEP) on 1) vascular permeability induced by histamine, 2) nasal mucosal permeability to horseradish peroxidase (HRP), and 3) eosinophilic epithelial infiltration. The vascular permeability induced by histamine was enhanced significantly and dose-dependently in DE-exposed guinea pigs. The HRP reaction products in epithelial cells and intercellular spaces were significantly and dose-dependently increased in those guinea pigs. Eosinophil infiltration into the epithelial layer was significantly increased in guinea pigs exposed to DE containing 3.2 mg/m3 DEP, and the reactivity of the nasal mucosa to histamine solution applied on the nasal mucosa was significantly enhanced in those guinea pigs. These findings suggest that DE may play an important role not only in promoting nasal hyperreactivity induced by the enhancement of absorption of antigen through the nasal epithelium, but also in inducing eosinophil infiltration in nasal mucosa and enhancing nasal mucosal reactivity.

Association of 5' CpG demethylation and altered chromatin structure in the promoter region with transcriptional activation of the multidrug resistance 1 gene in human cancer cells

Selection of human cells for resistance to vincristine or doxorubicin often induces overexpression of the multidrug resistance 1 gene (MDR1), which encodes the cell surface P-glycoprotein, as a result of gene amplification or transcriptional activation. However, the precise mechanism underlying such transcriptional activation of MDR1 remains unclear. The relation between methylation status of CpG sites in the MDR1 promoter region and transcriptional activation of MDR1 has now been investigated. The P-glycoprotein-overexpressing, multidrug-resistant KB/VJ300 and KB-C1 cells, which were established from human cancer KB3-1 cells, were examined; MDR1 is transcriptionally activated but not amplified in KB/VJ300 cells, whereas it is amplified in KB-C1 cells. Determination of the methylation status revealed that the MDR1 promoter region was hypomethylated in KB/VJ300 and KB-C1 cells, but hypermethylated in KB3-1 cells. Prior treatment of KB3-1 cells with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine resulted in a 90-fold increase in the frequency of vincristine-resistance. Of three lines, KB/CdR-1, KB/CdR-2, and KB/CdR-3, established from KB3-1 cells after exposure to 5-aza-2'-deoxycytidine, MspI/HpaII sites in the MDR1 promoter region were hypomethylated in KB/CdR-1 and KB/CdR-2 cells, but not in KB/CdR-3 cells. MDR1 mRNA expression was detected in KB/CdR-1 and KB/CdR-2 cells, but not in KB/CdR-3 cells. The binding of YB-1 and Sp1, transcription factors implicated in MDR1 expression, in the MDR1 promoter was not affected by the methylation status of a neighboring CpG sites. The MDR1 promoter region in KB/VJ300 cells showed an increased sensitivity to DNase I compared with that in KB3-1 cells, suggesting an altered chromatin structure. The methylation status of the promoter region may plays an important role in MDR1 overexpression and in acquisition of the P-glycoprotein-mediated multidrug resistance phenotype.

Complete remission of multiple hepatocellular carcinomas associated with hepatitis C virus-related, decompensated liver cirrhosis by oral administration of enteric-coated tegafur/uracil

We report a case of complete remission of multiple hepatocellular carcinomas after oral administration of enteric-coated tegafur/uracil. A 77-yr-old woman was diagnosed as having recurrent hepatocellular carcinoma associated with decompensated liver cirrhosis. We administered enteric-coated tegafur/uracil to this patient. After 1 month of oral administration, there was a decrease in tumor markers. An image analysis showed disappearance of hepatocellular carcinoma. No recurrence of the hepatocellular carcinoma was recognized for 18 months up to the time of the patient's death, which was due to massive bleeding from a hemorrhagic rectal ulcer. At autopsy, the tumor lesion had necrotized. Oral administration of enteric-coated granules containing tegafur/uracil may provide an effective treatment for hepatocellular carcinoma.

Cellular balance of glutathione levels through the expression of gamma-glutamylcysteine synthetase and glutathione thiol transferase genes in human hepatic cells resistant to a glutathione poison

Buthionine sulfoximine (BSO) is a synthetic amino acid that irreversibly inhibits glutathione biosynthesis and deranges reduced glutathione (GSH) metabolism in liver cells. We isolated two BSO-resistant lines, HLE/BSO2-1 and HLE/BSO2-2, from human hepatic HLE/WT cells. Cellular levels of the Pi class glutathione thiol transferase (GSTP1) were 3-fold lower in BSO-resistant lines than in HLE/WT cells. By contrast, gamma-glutamylcysteine synthetase (GCS) heavy subunit (GCSh) mRNA levels were markedly decreased in HLE/BSO2-1 and HLE/BSO2-2 as compared with HLE/WT. The expression of a dominant-negative mutant of c-Jun inhibited the GCSh promoter activity in HLE/WT, but not in HLE/BSO2-1. Cellular levels of AP-1, however, were not decreased in either BSO-resistant cell line. Transfection of GCSh promoter of various lengths driven reporter constructs showed no sequence-specific increase in the promoter activities in HLE/BSO2-1. However, transfection of GSTP1 cDNA into HLE/BSO2-1 and HLE/BSO2-2 restored the levels of GCSh mRNA and the GCSh promoter activity to those of HLE/WT. Sequences between -315 and -241 bp of the 5' region contained an AP-1 site responsible for the enhanced GCSh promoter activity in GSTP1 transfectants of HLE/BSO2-1. In vivo footprint analysis showed a specific protection of the AP-1 site on GCSh promoter in GSTP1 transfected HLE/BSO2-1. GSH homeostasis thus appears to be maintained by an interaction between GSTP1 and GCS in human hepatic cells resistant to the GSH poison.

Analysis of 8-hydroxyguanine in rat kidney genomic DNA after administration of a renal carcinogen, ferric nitrilotriacetate

The frequency of oxidative base damage, such as 8-hydroxyguanine (8-OH-Gua), was determined at the nucleotide level of resolution using the ligation-mediated PCR technique. Administration of a renal carcinogen, ferric nitrilotriacetate (Fe-NTA), is known to induce oxidative stress and subsequent formation of 8-OH-Gua in the rat kidney. Whole genomic DNA was isolated from the rat kidney after or without Fe-NTA treatment and then cleaved with hot piperidine. In order to assess the frequency of 8-OH-Gua formation, we chose three genes, the tumor suppressor gene p53, the heat shock protein 70 (HSP70-1) gene and the Na,K-ATPase alpha1 subunit gene. No alteration in the cleavage profile was observed in the p53 and HSP70 genes after Fe-NTA treatment. In the case of the p53 gene, a low incidence of point mutations has been observed in this carcinogenesis system. On the other hand, time-dependent alterations, corresponding to the time course of overall 8-OH-Gua formation and repair, were detected in the promoter region of the Na,K-ATPase alpha1 subunit gene. GpG and GpGpG in specific regions seem to be hotspots for the formation of 8-OH-Gua. These results were confirmed by formamidopyrimidine-DNA glycosylase-dependent DNA cleavage patterns. Thus, oxidative base damage, such as 8-OH-Gua, was not distributed uniformly along the whole genome, but seemed to be restricted to particular genes and regions.

Catecholamine metabolism inhibitors and receptor blockades only partially suppress cardiac hypertrophy of juvenile visceral steatosis mice with systemic carnitine deficiency

To clarify the mechanism of cardiac hypertrophy in carnitine-deficient JVS mice, we studied the possible role of catecholamine metabolism. Cardiac hypertrophy occurs 2 weeks after birth. The turnover of norepinephrine in the ventricles of JVS mice at 2 weeks was 3 times that of control, but it was not different from control at 5 days when the heart weight was not changed. To evaluate the accelerated norepinephrine turnover, we examined the effects of catecholamine metabolism inhibitors (alpha-methyltyrosine and 6-hydroxydopamine) and catecholamine receptor blockades (propranolol, prazosin and yohimbine) on the ratio of heart weight to body weight (HW/BW) and on the augmented expression of atrial natriuretic peptide (ANP) and the down-regulated carnitine deficiency-associated gene expressed in ventricle (CDV-1). The HW/BW ratio in JVS mice treated with catecholamine metabolism inhibitors and receptor blockades was significantly lower than in JVS mice without treatment, but still higher than in controls treated with each drug and in JVS mice treated with carnitine. The HW/BW ratio of JVS mice with propranolol was not significantly different from that of JVS mice treated with catecholamine metabolism inhibitors and was significantly lower than that of JVS mice treated with prazosin and yohimbine. Northern blot analysis showed that the altered expression of ANP and CDV-1 was not corrected in the ventricles of JVS mice treated with any of the drugs except carnitine. These results suggest that the catecholamine metabolism accelerated in JVS mice ventricles at 2 weeks is not the major cause of cardiac hypertrophy, but probably promotes cardiac hypertrophy mainly through the beta-adrenergic signaling pathway. The aberrant gene expression of ANP and CDV-1 found in JVS mice seems to be independent of catecholamine metabolism, and mediated primarily by the systemic carnitine deficiency.

Isolation and characterization of a human hepatic epithelial-like cell line (AKN-1) from a normal liver

The isolation and characterization of human liver cell lines are rather difficult due to limited material and poor growth in cell culture. In this report, we present the isolation, culture and characterization of a new epithelial-like liver cell line (AKN-1) with a heterogeneous cell population and many characteristics of the biliary epithelium. The AKN-1 cell line stained positively with antibodies to epithelial cytokeratin polypetides CK 8, 18, and 19. In addition, the cell line expressed the anti-human epithelial-related antigen (MOC-31), the human epithelial antigen (HEA), and the gamma-glutamyl transpeptidase, the hematopoietic growth factor, stem cell factor, and also its receptor, c-kit. The cell line failed to express albumin and factor 8 by immunohistochemistry. It did show, however, a twofold increase in 7-ethoxyresorufin-O-deethylase activity. Cytogenetic characterization revealed rare breakpoints in chromosome 2, which to our knowledge, have not yet been reported in liver cells.

Structural and functional analysis of the control region of the human DNA topoisomerase II alpha gene in drug-resistant cells

We have previously shown that the DNA topoisomerase II alpha (topo II alpha) gene is down-regulated in VP16/VM26-resistant cells at the transcriptional level. To determine the DNA elements responsible for down-regulation, the transcriptional activities of luciferase reporter constructs containing various lengths of the promoter sequences were investigated by transient transfection of two resistant cell lines, KB/VP2 and KB/VM4. The transcriptional activities of the full-length promoter (-295 to +85) and of three deletion constructs (-197, -154 and -74 to +85) were significantly down-regulated in resistant cells. In contrast, the transcriptional activity of the minimal promoter (-20 to +85) in resistant cells was similar to that in parental KB cells. Furthermore, introduction of a mutation in ICE1 abolished the down-regulation of the topo II alpha promoter activity in drug-resistant cells. In vivo footprinting analysis of topo II alpha gene promoter revealed several specific protein-binding sites, a GC box, ICE1, ICE2 and ICE3. In vivo footprinting analysis also identified a cluster of hypersensitive sites. However, there was no marked difference in protein-binding sites between parental and resistant cells. To confirm our previous results, we have established the VP16-resistant cell lines T12-VP1 and T12-VP2 from T12 cells derived from human bladder cancer T24 cells stably transfected with the chloramphenicol acetyltransferase reporter gene driven by the topo II alpha gene promoter. The expression to topo II alpha was down-regulated in both cell lines. We also found that CAT gene expression was significantly decreased to one-fifth of that in T12 parental cells. These results suggest that the expression of the topo II alpha gene requires the binding of multiple factors to the core promoter and is down-regulated at the transcriptional level, probably through binding of a negative factor to ICE1 in drug-resistant cells.

Control of O-glycan branch formation. Molecular cloning of human cDNA encoding a novel beta1,6-N-acetylglucosaminyltransferase forming core 2 and core 4

A novel human UDP-GlcNAc:Gal/GlcNAcbeta1-3GalNAcalpha beta1, 6GlcNAc-transferase, designated C2/4GnT, was identified by BLAST analysis of expressed sequence tags. The sequence of C2/4GnT encoded a putative type II transmembrane protein with significant sequence similarity to human C2GnT and IGnT. Expression of the secreted form of C2/4GnT in insect cells showed that the gene product had UDP-N-acetyl-alpha-D-glucosamine:acceptor beta1, 6-N-acetylglucosaminyltransferase (beta1,6GlcNAc-transferase) activity. Analysis of substrate specificity revealed that the enzyme catalyzed O-glycan branch formation of the core 2 and core 4 type. NMR analyses of the product formed with core 3-para-nitrophenyl confirmed the product core 4-para-nitrophenyl. The coding region of C2/4GnT was contained in a single exon and located to chromosome 15q21.3. Northern analysis revealed a restricted expression pattern of C2/4GnT mainly in colon, kidney, pancreas, and small intestine. No expression of C2/4GnT was detected in brain, heart, liver, ovary, placenta, spleen, thymus, and peripheral blood leukocytes. The expression of core 2 O-glycans has been correlated with cell differentiation processes and cancer. The results confirm the predicted existence of a beta1,6GlcNAc-transferase that functions in both core 2 and core 4 O-glycan branch formation. The redundancy in beta1,6GlcNAc-transferases capable of forming core 2 O-glycans is important for understanding the mechanisms leading to specific changes in core 2 branching during cell development and malignant transformation.

Adenosine and neopterin levels in cerebrospinal fluid of patients with neurological disorders

We determined the cerebrospinal fluid (CSF) levels of adenosine, a mediator of cerebral blood flow regulation, and neopterin, a macrophage-producing compound, in patients with neurological disorders. Compared to control subjects, the adenosine levels were significantly increased in the patients with acute-stage cerebral infarction (n=12, p<0.0001), acute meningitis (n=10, p<0.0001), or amyotrophic lateral sclerosis (ALS, n=12, p<0.05) (Mann-Whitney U-test). The neopterin levels were significantly increased in the 41 patients with human T-lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis (HAM/TSP, p<0.0001), acute meningitis (p<0.0001), ALS (p<0.05) (Mann-Whitney U-test), or acute-stage cerebral infarction (p<0.005, Student's t-test). In the analysis of 41 HAM/TSP patients, the neopterin levels were significantly correlated with the cell number and glucose levels in the CSF, and were a sensitive marker of inflammation. Several of the HAM/TSP patients with increased adenosine levels were probably complicated with other diseases. The increased neopterin levels in the HAM/TSP group persisted, suggesting that the mononuclear cellular infiltration remained for a long time.

Transcription factor Y-box binding protein 1 binds preferentially to cisplatin-modified DNA and interacts with proliferating cell nuclear antigen

The Y-box binding protein (YB-1) binds to inverted CCAAT box sequences that are present in the promoter region of many genes. We previously showed that YB-1 is overexpressed in human cancer cell lines that are resistant to cisplatin and that the depletion of YB-1 by transfection of a vector expressing YB-1 antisense RNA increases the sensitivity of human cancer cells to cisplatin. To determine whether YB-1 can bind to cisplatin-modified DNA, we fused YB-1 cDNA to glutathione S-transferase (GST) cDNA and purified the resulting GST fusion protein. When we tested the fusion protein with unmodified or cisplatin-modified oligonucleotides, we found that GST-YB-1 bound more strongly to cisplatin-modified oligonucleotides, as did GST fusion proteins of high mobility group 1 (HMG1), HMG2, and xeroderma pigmentosum group A protein. When we assayed the ability of proliferating cell nuclear antigen (PCNA) to interact with the GST fusion proteins, we observed binding to YB-1 but not to HMG1, HMG2, or xeroderma pigmentosum group A. Subsequent experiments demonstrated that YB-1 and PCNA interact directly via the COOH-terminal region of YB-1. Using immunochemical coprecipitation methods, we observed binding of YB-1 and PCNA in vivo. These results suggest that YB-1 can function as a recognition protein for cisplatin-damaged DNA and that it may be important in DNA repair or in directing the cellular response to DNA damage.

Effect of selegiline on dopamine concentration in the striatum of a primate

Monoamine oxidase (MAO) has two subtypes, A and B, that have different distributions between the rodent and the human. In the striatum, dopamine (DA) of the rat seems to be metabolized by MAO A, and DA of the human is largely deaminated by MAO B. MAO in the striatum of common marmosets is also type B. Using in vivo microdialysis, we investigated the pharmacological activity of selegiline, a selective irreversible inhibitor of MAO B, in the striatum of marmosets. Intraperitoneal co-administration of selegiline (1 mg kg-1, i.p.) with levodopa/carbidopa (10/2.5 mg kg-1, i.p.) did not significantly increase extracellular concentration of DA in the striatum of common marmosets compared with control animals receiving levodopa/carbidopa alone. Daily pretreatment with 0.1 mg kg-1 (i.p.) selegiline for two weeks, however, dramatically increased extracellular concentration of DA to about seven times that of control animals treated with levodopa/carbidopa alone in marmosets. Such an increase in extracellular concentrations of DA could not be observed in a similar study with Wistar rats. This study showed that chronic administration of a small dose of selegiline caused a marked increase in extracellular DA concentration in the striatum of primates, but not in the rodents.

Analysis of serum cytokine levels in primary biliary cirrhosis patients and healthy adults

By using commercially available ELISA kits, serum IL-6 and TNF-alpha levels in healthy adults, and the levels of various cytokines in patients with primary biliary cirrhosis or chronic viral liver diseases, were investigated. IL-6 levels of healthy subjects were distributed in a wide range, and the distribution pattern was similar to those of the patients. TNF-alpha levels tended to be low in females in their 30s, but there were no abnormalities in the patients. Characteristic findings, in the primary biliary cirrhosis patients, were an increase of IFN-gamma and IL-2 levels, and a decrease of GM-CSF levels (P < 0.05). IL-8 levels were higher in the patients than in the healthy subjects (P < 0.05), and the increase was remarkable in chronic viral liver disease patients. We believe that measurement of serum cytokine levels as a clinical immunological test is highly useful. Further development of simpler, more rapid, and more sensitive analysis methods is desired.

Areas of sinusoidal surface hepatocyte nuclear predominance in type C chronic hepatitis

AIMS/BACKGROUND

Thick hepatic plates have been considered one of the morphological characteristics of hepatocyte regeneration in cirrhotic nodules. They can be recognized by the sinusoidal surface predominance of their nuclei. We have investigated the prevalence of this in HBV and HCV infections.

METHODS AND RESULTS

This feature was more frequently present in type C chronic hepatitis with low activity of inflammation and low grade of fibrosis, than with type B chronic hepatitis. Additionally, this area of sinusoidal surface hepatocyte nuclear predominance (ASSHNP) was seen in zone II, rather than in periportal zones, in type C chronic hepatitis. Clinical data were analyzed statistically. Immunohistochemical reactivity of type IV collagen, laminin, Ulex europaeus agglutinin 1 lectin (UEA-1), and factor VIII-related antigen were increased in ASSHNP. Immunohistochemical staining of Ki-67 antigen was performed in order to assess the regenerative capacity of this area and showed a low level of regeneration. Ultrastructure of this area in type C chronic hepatitis showed a decrease in the number of mitochondria and an increase of nuclear pleomorphism together with basement membrane formation in the space of Disse.

CONCLUSION

Although the cause of these abnormalities was not clarified in this study, it is suggested that they are related to chronic hepatitis C virus (HCV) infection per se, rather than regeneration or inflammatory activity. These changes may be significant in HCV-associated hepatocarcinogenesis.

Fibrosing cholestatic hepatitis after living related-donor renal transplantation

A 43-year-old man underwent living related-donor renal transplantation because of chronic renal failure in 1991. During the transplant period, both donor and recipient were seronegative for hepatitis B surface antigen (HBsAg). The donor was seropositive for antibody to hepatitis B surface antigen (anti-HBs) due to hepatitis B virus (HBV) vaccination. After transplantation, FK506 and methylprednisolone had been administered to the patient as immunosuppressants. In 1993, HBsAg appeared in his serum. His alanine aminotransferase level elevated gradually during 1995 and then in 1996, general fatigue, ascites and jaundice developed. At this time his serum was positive for hepatitis B e antibody, contained more than 100000 Meq/mL HBV-DNA and 100% precore mutant. Despite subsequent intensive therapy, liver dysfunction progressed and this patient died of hepatic failure 2 months following admission. At autopsy, the liver exhibited cholestasis, fibrosis extending from the portal tracts, mild inflammation and hepatocytes with a ground-glass appearance. In addition, HBsAg and hepatitis B core antigens had accumulated in the hepatocytes. Consequently, the final diagnosis was fibrosing cholestatic hepatitis (FCH) due to precore mutant HBV infection contracted after renal transplantation. It is unclear when and where the recipient liver became HBV infected. Nevertheless, after renal transplantation, while receiving immunosuppressive drugs, HBV appeared to have the potential to cause hepatic failure and FCH may have been a fatal complication for the recipient.

Microwave Spectroscopy of BrBO

The microwave spectra of the four isotopomers of the BrBO molecule (79Br10BO, 81Br10BO, 79Br11BO, and 81Br11BO) were observed in a dc glow discharge plasma of a mixture of boron tribromide vapor and oxygen gas. Rotational transitions of BrBO were measured for the ground state as well as for the vibrationally excited states, nu2 (bend) and nu3 (Br-B str.), for all of four isotopomers, and associated 2nu2, nu2 + nu3, and 2nu3 for the 11B species. The l = 0 substate of the 2nu2 state interacts with the nu3 state through the Fermi resonance. The rotational constants determined for the ground states of the four isotopomers yield the substitution structure, rs(Br&sbond;B) = 1.835791(70) Å and rs(B&dbond;O) = 1.20472(25) Å. The pi character and ionic character of the Br-B bond, which are estimated from the bromine quadrupole coupling constant eQq, are discussed through the comparison with those of related molecules such as BrCN and BrBS. Copyright 1998 Academic Press.

Structural analysis of peptide substrates for mucin-type O-glycosylation

The structures of three nine-residue peptide substrates that show differential kinetics of O-linked glycosylation catalyzed by distinct recombinant uridine diphosphate-N-acetylgalactosamine:polypeptide N-acetylgalactosaminyltransferases (GalNAc transferases) were investigated by NMR spectroscopy. A combined use of NMR data, molecular modeling techniques, and kinetic data may explain some structural features required for O-glycosylation of these substrates by two GalNAc transferases, GalNAc-T1 and GalNAc-T3. In the proposed model, the formation of an extended backbone structure at the threonine residue to be glycosylated is likely to enhance the O-glycosylation process. The segment of extended structure includes the reactive residue in a beta-like or an inverse gamma-turn conformation and flanking residues in a beta-strand conformation. The hydroxyl group of the threonine to be glycosylated is exposed to solvent, and both the amide proton and carbonyl oxygen of the peptide backbone are exposed to solvent. The exchange rate of the amide proton for the reactive threonine correlated well with substrate efficiency, leading us to hypothesize that this proton may serve as a donor for hydrogen bonding with the active site of the enzyme. The oxygens of the residue to be glycosylated and several flanking residues may also be involved in a set of hydrogen bonds with the GalNAc-T1 and -T3 transferases.

[Dermal application of lisuride on parkinsonism induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in the common marmoset and on cases with Parkinson's disease]

Dermal administration is a nonoral drug delivery system that can keep the concentration of a drug in the body at a proper level for a long time. This is suitable especially in patients in the advanced stages of Parkinson's disease with a wearing-off phenomenon (short duration of effects on antiparkinsonian drugs), or in postoperative patients who cannot be treated with oral administration. We studied the effects of lisuride, a dopamine receptor agonist, in the dermal application on MPTP-treated common marmosets and on 5 patients with Parkinson's disease. Lisuride was applied to 4 x 5 cm of skin of the abdomen of monkeys. In patients with Parkinson's disease, lisuride was applied to the skin of the chest. The agent reversed akinesia of MPTP-treated animals within 30 min following the application and relieved the animal of parkinsonism for 5 days at a dose of 2 mg/kg. In patients, the dermal application of lisuride increased the duration of the ON period at doses of 1 to 2 mg/kg. These results suggest that the dermal application of lisuride is a useful treatment in parkinsonism.

A family of human beta3-galactosyltransferases. Characterization of four members of a UDP-galactose:beta-N-acetyl-glucosamine/beta-nacetyl-galactosamine beta-1,3-galactosyltransferase family

BLAST analysis of expressed sequence tags (ESTs) using the coding sequence of a human UDP-galactose:beta-N-acetyl-glucosamine beta-1, 3-galactosyltransferase, designated beta3Gal-T1, revealed no ESTs with identical sequences but a large number with similarity. Three different sets of overlapping ESTs with sequence similarities to beta3Gal-T1 were compiled, and complete coding regions of these genes were obtained. Expression of two of these genes in the Baculo virus system showed that one represented a UDP-galactose:beta-N-acetyl-glucosamine beta-1, 3-galactosyltransferase (beta3Gal-T2) with similar kinetic properties as beta3Gal-T1. Another gene represented a UDP-galactose:beta-N-acetyl-galactosamine beta-1, 3-galactosyltransferase (beta3Gal-T4) involved in GM1/GD1 ganglioside synthesis, and this gene was highly similar to a recently reported rat GD1 synthase (Miyazaki, H., Fukumoto, S., Okada, M., Hasegawa, T., and Furukawa, K. (1997) J. Biol. Chem. 272, 24794-24799). Northern analysis of mRNA from human organs with the four homologous cDNA revealed different expression patterns. beta3Gal-T1 mRNA was expressed in brain, beta3Gal-T2 was expressed in brain and heart, and beta3Gal-T3 and -T4 were more widely expressed. The coding regions for each of the four genes were contained in single exons. beta3Gal-T2, -T3, and -T4 were localized to 1q31, 3q25, and 6p21.3, respectively, by EST mapping. The results demonstrate the existence of a family of homologous beta3-galactosyltransferase genes.

Inhibition by diazepam of ketamine-induced hyperlocomotion and dopamine turnover in mice

PURPOSE

To investigate the effects of the benzodiazepine diazepam on ketamine-induced hyperlocomotion and dopamine turnover.

METHODS

Adult male ddY mice were used (n = 218). Locomotor activity was measured with four circular activity cages equipped with three photocell sensor units. Interruptions by a mover of the infrared light Peams were recorded on electromechanical counters, and automatically printed every 10 min for three hours after the ketamine injection. All drugs were administered intraperitoneally (i.p.). The concentrations of dopamine and its metabolites in discrete brain regions were measured by high performance liquid chromatography with electrochemical detection.

RESULTS

Ketamine (30 mg.kg-1) increased total locomotor activity counts for three hours to 442% of control in mice (P = 0.0001). Diazepam, 3 and 10 mg.kg-1, inhibited, in a dose-dependent fashion, this ketamine-induced hyperlocomotion by 26% (P = 0.0111) and 59% (P = 0.0001), respectively. Regional brain dopamine assays revealed that ketamine (30 mg.kg-1) increased the homovanillic acid:dopamine ratio (one indicator of dopamine turnover) to 121% of control in the nucleus accumbens (P = 0.0065) and to 111% in the striatum (P = 0.0135) at peak locomotion. Diazepam, 3 and 10 mg.kg-1, returned this increase in dopamine turnover produced by ketamine to control levels both in the nucleus accumbens (P = 0.0061 and P = 0.0117, respectively) and in the striatum (P = 0.0004 and P = 0.0047, respectively).

CONCLUSION

These results suggest that the inhibition by diazepam of ketamine-induced hyperlocomotion may be related to its ability to suppress the activation of dopamine neurons in the nucleus accumbens and striatum.

The role of an inverted CCAAT element in transcriptional activation of the human DNA topoisomerase IIalpha gene by heat shock

Expression of the DNA topoisomerase IIalpha (topoIIalpha) gene is highly sensitive to various environmental stimuli including heat shock. The amount of topoIIalpha mRNA was increased 1.5-3-fold 6-24 h after exposure of T24 human urinary bladder cancer cells to heat shock stress at 43 degreesC for 1 h. The effect of heat shock on the transcriptional activity of the human topoIIalpha gene promoter was investigated by transient transfection of T24 cells with luciferase reporter plasmids containing various lengths of the promoter sequence. The transcriptional activity of the full-length promoter (nucleotides (nt) -295 to +85) and of three deletion constructs (nt -197 to +85, -154 to +85, and -74 to +85) was increased approximately 3-fold 24 h after heat shock stress. In contrast, the transcriptional activity of the minimal promoter (nt -20 to +85), which lacks the first inverted CCAAT element (ICE1), the GC box, and the heat shock element located between nt -74 and -21, was not increased by heat shock. Furthermore, the transcriptional activity of promoter constructs containing mutations in the GC box or heat shock element, but not that of a construct containing mutations in ICE1, was significantly increased by heat shock. Electrophoretic mobility shift assays revealed reduced binding of a nuclear factor to an oligonucleotide containing ICE1 when nuclear extracts were derived from cells cultured for 3-24 h after heat shock. No such change in factor binding was apparent with an oligonucleotide containing the heat shock element of the topoIIalpha gene promoter. Finally, in vivo footprint analysis of the topoIIalpha gene promoter revealed that two G residues of ICE1 that were protected in control cells became sensitive to dimethyl sulfate modification after heat shock. These results suggest that transcriptional activation of the topoIIalpha gene by heat shock requires the release of a negative regulatory factor from ICE1.

Ultrastructural and histochemical study of the motor end plates of the intrinsic laryngeal muscles in amyotrophic lateral sclerosis

Motor end plates of the intrinsic laryngeal muscles in amyotrophic lateral sclerosis (ALS) were examined light and electron microscopically. Light microscopically, typical neurogenic changes such as small angulated fibers and grouped atrophy were found in the intrinsic laryngeal muscles. Acetylcholinesterase (AchE) activities of the neuromuscular junctions (NMJ) of many fibers in ALS were decreased as compared with those of the controls. Some end-plate areas on each fiber detected by AchE histochemistry were larger than those of the controls. Ultrastructurally, muscle fibers in ALS specimens showed several changes; increased number of lipofuscin granules and/or nuclei, numerous mitochondria, and disappearance of the myofilaments. The NMJ also showed various degrees of structural changes. Some NMJ appeared almost normal. Others showed the absence of nerve terminals and Schwann cells covering the former junctional sites. Their primary synaptic clefts were flattened, and the secondary synaptic clefts were relatively well preserved. On occasion, several small nerve terminals were seen on the severely distorted postsynaptic folds, suggesting regenerative findings. In severely degenerated muscle fibers, the NMJ could not be found.

Effects of acute or prolonged administration of cabergoline on parkinsonism induced by MPTP in common marmosets

The effects of a single treatment or chronic administration of cabergoline (1-[(6-allylergolin-8beta-yl)carbonyl]-1-[3-(dimethylamino)p ropyl]-3-ethyl-urea), a potent, long-lasting dopamine receptor agonist, on parkinsonism induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in common marmosets were studied. The administration of 0.2 mg/kg or a higer dose of cabergoline began to reverse parkinsonism-like symptoms 60 min after a subcutaneous injection, and showed steady and constant effects throughout the observation period. For prolonged administration, 0.2 mg/kg cabergoline was injected daily for 22 consecutive days. Locomotor activity in MPTP-treated animals increased until it reached its peak on the third day, then it gradually decreased. Akinesia scores, rating the quality of movements, were also improved, and the improvement was sustained up to the last day of chronic administration. None of the animals developed abnormal behaviors after either acute or chronic administration. These results suggest that cabergoline has long-acting effects in the marmoset model of parkinsonism, and that it will be a useful agent for the treatment of Parkinson's disease, particularly in cases with fluctuating motor disabilities.

Improvement of intestinal absorption of peptide drugs by glycosylation: transport of tetrapeptide by the sodium ion-dependent D-glucose transporter

A tetrapeptide (Gly-Gly-Tyr-Arg, GGYR), which is not transported by di- or tripeptide transporters, was glycosylated with p-(succinylamido)phenyl alpha- or beta-D-glucopyranoside (alpha,beta-SAPG) to investigate whether these glycosylated molecules are transported by the Na+-dependent D-glucose transporter. Their uptake into brush border membrane vesicles (BBMVs) and transport through the intestinal membrane were examined using the rapid filtration technique and the everted sac method. It was observed that glycosylation at the alpha-amino position of GGYR increased resistance to aminopeptidase activity and inhibited its degradation. When alpha- and beta-SAPG-GGYR were incubated with BBMVs, overshoot uptake was observed about 2 min after the start of incubation in the presence of an inward Na+ gradient. This uptake remained unaffected by the addition of GGYR while it was significantly inhibited when Na+ was replaced with K+ or alpha- and beta-SAPG-GGYR were incubated with BBMVs at 4 degrees C. Uptake was also markedly inhibited either with 1 mM phloridzin or 10 mM D-glucose. These findings suggested that the Na+-dependent glucose transporter (SGLT-1) played an important role in the uptake of both alpha- and beta-SAPG-GGYR into BBMVs. A comparison of alpha- with beta-SAPG-GGYR revealed that the amount of beta-SAPG-GGYR taken up was greater than that of alpha-SAPG-GGYR. From the everted sac method data, it was shown that the elimination clearance from the mucosal side, CLel, and permeation clearance to the serosal side, CLp, were 15.82+/-6.83 and 0.83+/-0.06 microL/min/cm for alpha-SAPG-GGYR and 44.52+/-3.61 and 3.50+/-0.81 microL/min/cm for beta-SAPG-GGYR, respectively, and that alpha-SAPG-GGYR was more resistant to enzymatic degradation than beta-SAPG-GGYR. Permeation of both alpha- and beta-SAPG-GGYR was inhibited in the presence of D-glucose and in the absence of a Na+ gradient, suggesting that both alpha- and beta-SAPG-GGYR were transported by the Na+-dependent D-glucose transporter. The permeation clearance transported by the Na+-dependent D-glucose transporter, (CLp)Na+, of beta-SAPG-GGYR was about 5 times greater than that for alpha-SAPG-GGYR. This result may be ascribable to the fact that the beta-form of glucose has higher affinity to SGLT-1 than the alpha-form. The results of the present study encourage further investigations on improvements in intestinal absorption of peptide drugs by glycosylation.

Quantitation of telomerase activity in hepatocellular carcinoma: a possible aid for a prediction of recurrent diseases in the remnant liver

Because telomerase activity is necessary for cell immortality and probably associated with tumor progression, we have evaluated a possible aid for quantitation of the activity to predict intrahepatic recurrences after surgery in patients with hepatocellular carcinoma (HCC). HCC tissues obtained by surgical resection from 20 patients were studied. Telomerase activity was expressed as peaks with a periodicity through a fluorescence-based telomeric repeat amplification protocol using an autosequencer, and the quantity of activity was calculated from peak areas. A ratio of fluorescence intensity depending on telomerase to that of an internal standard was used as a value of relative telomerase activity (RTA). RTA in serially diluted S100 extracts from HepG2 cells was well correlated with the amount of the extracts. The mean RTA value of 36.4 +/- 27.8 (mean +/- SD, 3.21 to 105) in 9 patients suffering from early recurrences after surgery was significantly higher than that (9.84 +/- 7.65; mean +/- SD, 3.00 to 29.0) in 11 patients without intrahepatic recurrences during the early period (P = .004). These results indicate that RTA value can be a useful predictor for intrahepatic recurrences during the early period after surgical resection of HCC.

Stimulation of nitric oxide synthase during oxidative endothelial cell injury

The purpose of this study was to determine changes in nitric oxide synthase (NOS) activity during the process of lethal oxidative cell injury following H2O2 treatment of endothelial cells. NOS activity was determined by measuring the conversion of [3H]arginine ([3H]Arg) to [3H]citrulline ([3H]Cit). Cell death was assessed by measuring the release of intracellular lactate dehydrogenase (LDH). Moreover, cell death and changes in cytosolic free Ca2+ (Ca(i)2+) were measured simultaneously using a confocal laser scanning system, and propidium iodide and fluo-3 as fluorescent indicators, respectively. Treatment with H2O2 (125-1000 microM) concentration dependently increased L-Cit formation from L-Arg, and a peak was obtained at 90 min after the addition of 500 or 1000 microM H2O2. The H2O2-induced increase in L-Cit formation was blocked completely by N(G)-nitro-L-arginine (L-NNA) or N(G)-methyl-L-arginine (L-NMA), both inhibitors of NOS. LDH release from endothelial cells was evoked from 120 min after the addition of H2O2 (125-1000 microM) in a concentration-dependent manner. Moreover, H2O2 increased Ca(i)2+ before cell death, and addition of Ca2+ chelator inhibited both the increase in L-Cit formation and LDH release by H2O2. The H2O2-induced LDH release was reduced by L-NNA, but not by L-NMA. These results suggest that H2O2 treatment of endothelial cells increases Ca(i)2+ before cell death, and stimulates NOS activity. The activation of NOS may be involved in oxidative endothelial cell death.

Flow cytometric analysis of IL-6 receptors on peripheral lymphocytes in patients with primary biliary cirrhosis

Interleukin-6 receptors (IL-6R) and interleukin-1 receptors (IL-1R) on lymphocyte surfaces were analyzed, using flow cytometry and dye-labeled IL-6 and IL-1 beta, to examine the clinical and immunological significance of these receptors. Incubation of peripheral blood mononuclear cells in the presence of mitogen resulted in a remarkable increase of lymphocytes expressing the IL-6 and IL-1 beta receptors on the cell surface. The increase in lymphocytes bearing these cytokine receptors may reflect an increase in stimulated lymphocytes. When peripheral blood from patients with primary biliary cirrhosis (PBC) was examined for these receptors, the percentage of IL-6R positive cells was significantly higher in the patients than in healthy controls (P < 0.01). The increase in IL-6R positive cells was only significant for the T lymphocyte fraction (P < 0.01). No significant change in IL-1R was observed. There was a significant positive correlation between the percentage of IL-6R positive T lymphocytes and the titer of antimitochondrial antibody in patients with PBC. These findings concerning IL-6R may be noteworthy elucidating autoimmune etiological features of PBC.

Metallothionein expression and concentrations of copper and zinc are associated with tumor differentiation in hepatocellular carcinoma

Metallothionein is the carrier protein of heavy metal ions, such as copper (Cu) and zinc (Zn). In this study, the relationships among immunohistochemical expression of metallothionein, concentrations of Cu and Zn, histological differentiation and proliferative activity of hepatocellular carcinoma were investigated in 51 cases. The concentrations of Cu and Zn in both tumor and non-tumor tissues were determined using electron probe microanalysis. Immunohistochemical expression of metallothionein in tumor tissues decreased with the degree of differentiation, whereas the number of hepatocytes positive for Ki-67 increased. Furthermore, the concentrations of Cu and Zn in tumor tissues decreased with the degree of histological differentiation in human hepatocellular carcinoma.

Increased dopamine turnover in the putamen after MPTP treatment in common marmosets

The differences in dopamine turnover rate between the putamen and the caudate nucleus in the striatum lesioned by a neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were studied in the common marmoset, a small New World monkey. Systemic administration of MPTP damaged equally and dose-dependently nigrostriatal dopaminergic neurons projecting both to the caudate nucleus and the putamen. The compensatory increase of dopamine turnover, however, occurred more prominently in the putamen than in the caudate. The neural connection and function of the caudate nucleus and the putamen have been differentiated anatomically or physiologically. The compensatory increase of dopamine turnover rate is another different aspect of functions between the caudate nucleus and the putamen. Dopaminergic neurons projecting to the putamen showed more prominent cell loss than those projecting to the caudate in Parkinson's disease or related disorders. The selective augmented turnover rate of lesioned dopaminergic neurons might be, at least partly, involved with selective degeneration of nigrostriatal neurons projecting to the putamen.

Changes in nitric oxide synthase activity during exposure to hydrogen peroxide in cultured endothelial cells

This study clarified the changes in maximum nitric oxide synthase (NOS) activity in cultured bovine aortic endothelial cells during exposure to hydrogen peroxide (H2O2). NOS activity was determined by measuring the conversion of [3H]arginine to [3H]citrulline. Ionomycin, a Ca2+ ionophore, was used to stimulate NOS activity. Addition of ionomycin (10(-5) M) increased the level of L-citrulline formation, and the ionomycin-induced increase in L-citrulline formation was stimulated by H2O2 pretreatment (15-90 min). Longer exposure to H2O2 (> or = 180 min) markedly inhibited the ionomycin-induced L-citrulline formation. The stimulation of ionomycin-induced L-citrulline formation by H2O2 was completely inhibited by N(G)-nitro-L-arginine (L-NNA) or N(G)-methyl-L-arginine (L-NMA), both blockers of NOS. Cell death which was determined by lactate dehydrogenase (LDH) release was induced from 120 min after the addition of H2O2. These findings suggest that the maximum L-citrulline formation from L-arginine, coupled with NOS activity, was increased by H2O2 treatment before cell death. The stimulation of NOS activity may be implicated in H2O2-induced endothelial cell death.

Effects of ketamine on dopamine metabolism during anesthesia in discrete brain regions in mice: comparison with the effects during the recovery and subanesthetic phases

The effects of ketamine on the levels of dopamine (DA), norepinephrine (NE), 5-hydroxytryptamine (5-HT, serotonin) and their metabolites were examined in discrete brain regions in mice. A high dose of ketamine (150 mg/kg, i.p.) did not change DA metabolism in the frontal cortex, nucleus accumbens, striatum and hippocampus, but did decrease it in the brainstem during anesthesia. In contrast, during recovery from the ketamine anesthesia, the high dose increased the level of homovanillic acid (HVA) in all brain regions. A low subanesthetic dose of ketamine (30 mg/kg, i.p.) increased the concentrations of both 3,4-dihydroxyphenylacetic acid (DOPAC) and HVA only in the nucleus accumbens. The DA level was not affected by any ketamine treatment. During ketamine anesthesia, the content of 3-methoxy-4-hydroxy-phenylglycol (MHPG) was decreased in the brainstem, whereas during recovery from anesthesia, the MHPG level was increased in the frontal cortex, nucleus accumbens and brainstem. The NE content was not altered in any region by ketamine treatment. The concentration of 5-hydroxyindoleacetic acid (5-HIAA) was reduced in the frontal cortex, striatum, hippocampus and brainstem during ketamine anesthesia. The 5-HT level was unaltered in all regions except the brainstem where it was reduced. In contrast, after anesthesia, the concentrations of both 5-HT and 5-HIAA were increased in the striatum. During the subanesthetic phase, however, the levels of NE, 5-HT and their metabolites were unchanged. These neurochemical results are consistent with the electrophysiological findings that a high dose of ketamine does not change the basal firing rates of nigrostriatal DA neurons during anesthesia, while low subanesthetic doses significantly increase those of ventral tegmental DA neurons.