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Biomedical subjects

M Esumi

Publications and source records attributed to M Esumi.

54 records · Page 3Linked to original sources
PubMed1992

Evaluation of three hepatitis C virus-related antibodies C100, KCL-163, JCC. Tests for screening blood donors.

To evaluate the most effective method for detecting hepatitis C virus (HCV) carriers in a large population of blood donors, HCV-related antibodies were measured in 919 donor serum samples using three different enzyme-linked immunosorbent assays. The antibodies were C100 and KCL-163, nonstructural proteins of HCV, as well as JCC, a translation product of the presumptive HCV core gene. Fourteen (1.5%), 12 (1.3%), and 13 (1.4%) specimens were positive for anti-C100, anti-KCL-163, and anti-JCC, respectively. HCV RNA was detected by the polymerase chain reaction in seven (25.0%) of the 28 specimens that were anti-HCV-positive by at least one of the three assays. Four of the seven specimens were detected by anti-C100 screening, while the remaining three were not. All seven specimens were positive for KCL-163 and/or JCC antibodies. These findings suggest that screening for both KCL-163 and JCC antibodies may be of particular use in accurately identifying HCV-positive blood.

Adult↗
PubMed1992

Interferon-inducible gene expression in chimpanzee liver infected with hepatitis C virus.

The molecular host response to hepatitis C virus (HCV) infection was examined by isolation of HCV-induced genes from a cDNA library constructed from chimpanzee liver during the acute phase of hepatitis C. Two cDNA clones, 130-7 and 130-51, were obtained by differential hybridization with cDNA probes prepared from poly(A)+ RNAs of infected and uninfected livers. Northern blot analysis revealed that the 130-7 and 130-51 cDNAs were expressed as 1.5- and 1.0-kb products, respectively, in chimpanzee liver and that their induction rates of the two were 20 and 4, respectively. Nucleotide sequence analyses of these cDNA inserts showed that the sequence of cDNA 130-7 was that of a class I major histocompatibility antigen and that the sequence of cDNA 130-51 was 98% homologous with a human interferon-inducible mRNA. These results suggest that HCV infection may actively induce interferon, which in turn induces the expressions of these interferon-inducible genes. Furthermore, the high expression of HLA class I antigen in the acute phase of hepatitis C suggests that liver cell injury in HCV infection may be mediated by cytotoxic T cells that recognize viral antigen in association with HLA class I antigen.

Animals↗
PubMed1991

Oncogene expression in the liver tissue of patients with nonneoplastic liver disease.

The expression of cellular oncogenes in nonneoplastic human liver tissue was examined to determine if there was a correlation between oncogene expression and physiologic regeneration in liver disease. Human liver tissue specimens from 70 patients with various histologic findings from almost normal to cirrhosis were examined (using northern blot analysis) for the expression of nine cellular oncogenes. With c-K-ras, four RNA bands (5.6-kilobase [kb], 2.1-kb, 1.5-kb, and 1.2-kb RNA species) were detected in all liver tissue examined. Expression of c-fos was also detected in a few samples examined when 50-micrograms samples of total RNA were applied. Other oncogenes such as H-ras, myc, erbB, raf, fms, fes, and myb were not detected. These results indicate that particular oncogene(s) may not be highly expressed during liver regeneration in human liver disease, or that populations of regenerating hepatocytes may be too small to show significant elevations of oncogene expression. The new finding of a constant expression of c-K-ras in human liver tissue suggests that it is linked to essential hepatocellular function rather than carcinogenesis.

Adult↗
PubMed1991

In vitro transcription of the hepatitis B virus gene by nuclear extracts of human hepatoma cells.

In vitro transcription of hepatitis B virus DNA (HBV DNA) was studied using nuclear extracts of human hepatoma cell lines. RNA polymerase II-dependent run-off transcription of pre-S mRNA under the control of pre-S1 promoter was observed in nuclear extracts obtained from HepG2 and PLC/PRF/5 cells, and the efficiencies in these extracts were significantly higher than those in nuclear extracts of non-liver cells such as HeLa, Molt-4, and Ehrlich. Analysis of run-off transcripts by the pre-S1 promoter, using deletion mutants of HBV DNA as templates and synthetic oligonucleotides as competitors, showed that hepatocyte nuclear factor 1 was necessary for initiation of in vitro transcription of pre-S mRNA. The run-off transcript of pregenome RNA was also detected and its initiation site was determined. Nuclear extracts of not only hepatoma cells but non-liver cells were active in transcription of pregenome RNA in vitro. However, run-off transcripts of S mRNA and X mRNA were not observed in this system. These results suggest that there were some differences between the mechanisms of HBV DNA transcription in vitro and in vivo. This in vitro transcription system will be useful for clarifying the mechanism regulating transcription of HBV DNA since the biochemical and functional characteristics of the nuclear factors can readily be analyzed.

Base Sequence↗
PubMed1991

Expression of a multidrug-resistance gene in human malignant lymphoma and related disorders.

The expression of mdr1 gene was measured to determine whether it plays a role in clinical resistance to chemotherapy of human malignant lymphomas. mdr1 expression was found in 4 of 9 cases resistant to chemotherapy. Expression of mdr1 was not detectable in any of 7 chemotherapy-sensitive tumors. The 2 cases of reactive lymphadenitis and the 3 samples of normal mononuclear cells did not show any expression of mdr1 gene, either. These results indicate that expression of the mdr1 gene is not always detectable in cases of malignant lymphoma resistant to chemotherapy, but the detectable expression of mdr1 gene may predict clinical resistance to chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

A cDNA clone closely associated with non-A, non-B hepatitis.

A lambda gt11 cDNA library was constructed from RNA purified from hepatitis B viral surface antigen-negative human plasma with high alanine aminotransferase activity. A cDNA clone, designated as C8-2, was isolated by immunoscreening with mixed sera from non-A, non-B hepatitis (NANBH) carrier and convalescent chimpanzees. The recombinant protein produced by C8-2 reacted specifically with sera of patients in the chronic phase of NANBH. The sequence of C8-2, 269 bp, did not hybridized with any human or chimpanzee genomic DNA, and had no homology with those of primates and viruses. The existence of this sequence in RNA of possibly infectious plasma was shown by RNA blot hybridization and by Southern blot analysis of products amplified by the polymerase chain reaction. These results strongly suggest that C8-2 is derived from the agent of this viral hepatitis.

Amino Acid Sequence↗
PubMed1990

Persistence of hepatitis B virus DNA after serological clearance of hepatitis B virus.

Using Southern blot technique, the state of hepatitis B virus (HBV) DNA in liver tissue was investigated in 16 patients who were sero-negative for hepatitis B surface antigen (HBsAg) but positive for its antibody (anti-HBs). In only one case, was HBV DNA found in liver tissue in a heterogeneously integrated form. In this case, digestion with Taq I demonstrated integrated HBV DNA as two definite bands at 1.8 and 0.5 kbp. This suggests that HBV DNA in some cases persists even after HBV infection has been cleared serologically. It is possible that this persistence of HBV DNA plays an important role in hepatocarcinogenesis.

DNA Probes↗
PubMed1989

Clonal state of human hepatocellular carcinoma and non-tumorous hepatocytes.

We determined the clonal state in specimens of hepatocellular carcinoma (HCC) and non-tumorous hepatocytes from the integration mode of hepatitis B virus (HBV) DNA. The integration mode of HBV DNA in several parts of the tumors and non-tumorous regions of the same liver, as well as in metastatic tumors, was examined using the Southern blot analysis. In 13 of the 14 cases of HCC, the liver tumors, including metastatic tumors in lymph nodes and the lungs, were monoclonal. In one case, a different HCC clone was found in one part of the liver tumor. The integration of HBV DNA was also observed in non-tumorous tissues in 38 of the 78 cases (49%) of chronic hepatitis with and without HCC; in 16 cases of chronic hepatitis in which HBV DNA was integrated, several clones of the hepatocytes that had HBV DNA integrated into their chromosomal DNA and had proliferated clonally were found in non-tumorous tissues. These clones were different from the tumor clone of the same liver. Thus HCCs were usually monoclonal. The development of different tumor clones appeared to be unusual, but the non-tumorous hepatocytes could have proliferated clonally from different multicentric clones before carcinogenesis. The clonal growth of the non-tumorous hepatocytes suggests that the integration of HBV DNA plays an important role in hepatocarcinogenesis.

Blotting, Southern↗
PubMed1989

Molecular cloning and sequence analysis of duck hepatitis B virus genomes of a new variant isolated from Shanghai ducks.

The genomes of duck hepatitis B virus (DHBV) from a brown duck (S5) and a white duck (S31) kept independently in Shanghai, China, were cloned and the complete nucleotide sequence of each virion DNA (DHBV-S5 and DHBV-S31) was determined. DHBV-S5 and DHBV-S31 were both 3027 bp in length and 6 bp longer than the other two DHBVs analyzed previously, DHBV16 and DHBV3. The genomes of DHBV-S5 and DHBV-S31 encoded three long overlapping open reading frames designated as P, S, and C. A possible new open reading frame was found in a complementary strand of each viral genome, as 336 bp for DHBV-S5 and 306 bp for DHBV-S31, respectively. A pair of 3-bp insertions were found in the overlapping region of pre-S2 and P and so two amino acids were inserted in this region in DHBV-S5 and DHBV-S31. The nucleotide sequence variation between DHBV-S5 and DHBV-S31 (4.9%) was similar to that between DHBV16 and DHBV3 (5.6%), and less than the variations between either of these Shanghai clones and DHBV16 or DHBV3 (9.5-10.4%). The amino acid sequence was also conserved in the two Shanghai clones but showed group difference from DHBV16 or DHBV3. Thus these two independent Shanghai clones of DHBV showed geographical characteristics of genomic structure.

Amino Acid Sequence↗
PubMed1989

State of hepatitis B virus DNA in hepatocytes of patients with noncarcinomatous liver disease. Its special relationship with necroinflammatory activity and the stage of disease.

By Southern blot hybridization, the state of hepatitis B virus (HBV) in the liver was investigated by utilizing needle biopsy specimens of 59 patients with hepatitis B surface antigen-positive noncarcinomatous liver disease. The tissue HBV DNA revealed a replicative form in 23 patients with chronic active hepatitis (48%) and an integrated form in 23 (48%) of these 48 patients. A liver with a replicative form was more frequently associated with hepatitis Be antigen (HBeAg), serum HBV DNA, and expression of hepatitis B core antigen than one without it. Integration of HBV DNA was more common in the anti-hepatitis Be phase or in the absence of necroinflammatory activity, and its frequency of occurrence roughly paralleled progression of liver disease: early, 21%; advanced, 56%; and cirrhotic stage, 61%.

Adult↗
PubMed1988

Influence of aflatoxin B1 intoxication on duck livers with duck hepatitis B virus infection.

In an attempt to determine the effect of aflatoxin B1 (AFB) intoxication on livers with duck hepatitis B virus (DHBV) infection, domestic ducks were given 0.1 mg of AFB/kg body weight twice a week for a maximum period of 54 weeks employing various experimental designs. The ducks were infected with DHBV by i.v. inoculation of DHBV-positive sera within 24 h posthatch. The livers were examined histologically, immunohistochemically, and ultrastructurally, and the livers and sera were examined by molecular hybridization for DHBV DNA. AFB administration induced hepatocellular necrosis and marked biliary cell proliferation of the periportal areas, and finally liver cirrhosis. On short-term administration, the hepatocytes of DHBV-infected livers revealed a marked increase in incomplete particles of DHBV by immunostaining and electron microscopy, as compared to those without its administration. Long-term AFB administration provoked frequent nodular or cirrhotic changes. There was no significant increase in frequency of these changes in DHBV-positive ducks as compared to DHBV-negative ones. AFB administration induced hepatocellular carcinoma (HCC) in one DHBV-positive duck and in two DHBV-negative ducks. The HCC and cirrhotic livers revealed extrachromosomal but no integrated form of DHBV DNA by Southern blot hybridization analysis. Immunostaining demonstrated a heterogeneous distribution of DHBV from area to area in nodular and cirrhotic livers. Thus, AFB intoxication provoked various liver disorders independent of DHBV infection, and neither a cocarcinogenic effect of AFB and DHBV nor integration of viral DNA into the genome of neoplastic and nonneoplastic tissues was observed in the present experiments. Generally speaking, DHBV infection did not appear to accelerate hepatic disorders induced by AFB intoxication. However, AFB administration altered the DHBV in the liver in terms of its amount and distribution.

Aflatoxin B1↗
PubMed1988

Frequent integration of hepatitis B virus DNA in noncancerous liver tissue from hepatocellular carcinoma patients.

To investigate the relationship between hepatocarcinogenesis and integration of hepatitis B virus (HBV) DNA in the cellular DNA of the liver, we studied the integration of HBV DNA in various noncancerous regions of the liver from 31 patients using Southern blot analysis. Of 13 patients without hepatocellular carcinoma (HCC), 4 had heterogeneously integrated HBV DNA. Of the latter four patients, two had chronic liver disease, and two had nonspecific histological changes. In contrast, integration of HBV DNA was found in noncancerous tissue from 11 of 18 patients with HCC. In eight patients, homogeneous integration was found in noncancerous tissue, and restriction fragments of integrated HBV DNA were different from those found in cancerous tissue. Moreover, integration of HBV DNA was found in all portions examined from the same liver, and homogeneously integrated HBV DNA showed different restriction patterns in different areas. These results suggest that integration of HBV DNA may occur in heterogeneous sites of cellular DNA before hepatocarcinogenesis. Subsequently, multi-focal clonal populations develop from these hepatocytes, especially frequently in the case of HCC. Integrated HBV DNA may play an important role in the clonal growth of hepatocytes, although the development of HCC requires additional factors.

Blotting, Southern↗
PubMed1986

Clonal origin of human hepatoma determined by integration of hepatitis B virus DNA.

The hepatitis B virus genome is integrated in cellular DNA of human hepatocellular carcinoma from hepatitis B surface antigen-positive patients. Using this phenomenon, we determined the clonal origin of hepatocellular carcinoma from the integration mode of hepatitis B virus DNA. The molecular size and the number of restriction fragments of integrated hepatitis B virus DNA in several parts of tumors in the same liver and in metastatic tumors were compared by Southern blot analysis. Of 14 cases of hepatoma, 13 cases were monoclonal; in one case, a different clone of hepatoma was found in one part of the tumor. In three of 13 cases of monoclonal hepatoma, metastatic tumors in lymph nodes and the lung were also examined and found to be the same clone as the liver tumors. These results indicate that hepatocellular carcinomas were usually generated from a single tumor cell even though tumor cells spread in the liver and invaded other organs for a long time. Development of different clones of tumor was apparently unusual but was observed in one case of hepatocellular carcinoma.

Carcinoma, Hepatocellular↗
PubMed1983

Sphingomyelin is a possible constituent of binding sites for the tumor promoters phorbol ester, indole alkaloids and polyacetates.

Specific binding of 12-0-tetradecanoylphorbol-13-acetate to the epidermal particulate fraction was susceptible to phospholipase A2 and phospholipase C, but was almost resistant to protease and completely resistant to a mixture of several glycosidases. Of vesicles prepared from five phospholipids associated with the epidermal particulate fraction, sphingomyelin vesicles bound 12-0-tetradecanoylphorbol-13-acetate specifically and most effectively. This binding was inhibited by not only phorbol esters but also two other classes of tumor promoters, indole alkaloids and polyacetates. These results suggest that sphingomyelin is involved in the binding sites of tumor promoters to the cell membrane.

Acetates↗
PubMedDate not supplied

Occurrence and ultrastructural localization of duck hepatitis B virus in the liver of ducks after experimental infection.

A sequential study was performed to investigate the occurrence and localization of duck hepatitis B virus in the liver of domestic ducks utilizing the indirect immunoperoxidase method and electron microscopy. Seventeen ducklings were injected intravenously with duck hepatitis B virus-positive serum within 24 hr after hatching and were subsequently sacrificed on the 2nd, 3rd, 4th, 5th, 27th and 44th day after injection. Nine ducklings were not injected and were used as a negative control. Duck hepatitis B virus DNA by spot hybridization using a [3P]-labeled probe occurred in trace amounts on the 2nd day and in large amounts on the 4th day after inoculation. Immunoreactivity for DHBV was seen in the hepatocytes, sporadically on the 2nd day and diffusely on the 4th day, and also in the biliary epithelial cells on the 27th day. Both kinds of cells revealed staining in the cytoplasm but not in the nucleus. Virus particles were recognized by electron microscopy in the hepatocytes beginning on the 4th day. The hepatocytes had many incomplete virus particles, 40 to 61 nm in diameter, and a few complete virus particles, 40 nm in diameter, in the cisternae of the rough and smooth endoplasmic reticula. Such particles and the endoplasmic reticulum showed reaction products for duck hepatitis B virus by immunoelectron microscopy. There were clusters of core particles, 27 nm in diameter, in the hyaloplasm around peroxisomes where an assembly of cores appeared to occur. No conspicuous virus particles were recognized in the biliary epithelial cells. The similarities and differences in virus localization between duck hepatitis B virus and hepatitis B virus are discussed.

Animals↗
PubMedDate not supplied

Two types of sporadic multiple colorectal cancers with and without HNPCC-like genetic instability.

BACKGROUND/AIMS: Sporadic multiple colorectal cancers (MCCs) potentially have similar genetic alterations to hereditary nonpolyposis colorectal cancers (HNPCCs), but genetically unstable MCCs other than HNPCCs are not well characterized. We report the frequency of HNPCC-like sporadic multiple colon cancers and their characterization as for HNPCC-related gene mutations. METHODOLOGY: Microsatellite instability (MSI) at 12 microsatellite loci was examined by a polymerase chain reaction in 19 cases each of MCC and single colorectal cancer (SCC). The target sequences of MSI, transforming growth factor beta type II receptor (TGF beta RII) gene, and the HNPCC genes, hMSH2 and hMLH1, were amplified and analyzed for mutations by sequencing. RESULTS: In 5 of 19 cases with MCC, MSI was observed at more than 4 microsatellite loci, and the other cases including all SCCs showed no MSI or MSI(+) at a single locus. In 4 of the 5 severe MSI(+) cases, a 10-bp adenine tract at codons 125-128 of the TGF beta RII gene was mutated. In terms of the hMSH2 and hMLH1 genes, only silent mutations and non-critical amino acid substitutions were found. CONCLUSIONS: We found severe MSI in 26% of sporadic multiple colorectal cancers. Mutations of the TGF beta RII gene are closely associated with severe MSI(+) MCCs as observed in HNPCC, suggesting that these MCCs develop by the similar carcinogenic process to HNPCC.

Adaptor Proteins, Signal Transducing↗
PubMedDate not supplied

Distinct relationship between polypoid growth type and sporadic colorectal carcinomas with microsatellite instability.

BACKGROUND/AIMS: This study was carried out to clarify whether colorectal carcinomas with MSI (microsatellite instability) is correlated with growth types of invasive carcinomas. METHODOLOGY: Samples of tumor tissue and adjacent normal mucosa were obtained from 45 patients with sporadic advanced colorectal cancer. The MSI was assessed by the mobility shift assay of microsatellite and VNTR (variable numbers of tandem repeat) alleles using 12 markers. Tumors with four or more positive loci were determined to be MSI positive. The polyadenine tract (A)10 of the third exon in TGF beta RII was also assessed by mobility shift assay of DNA fragments amplified with primers. Histological examination was performed to divide all tumors into polypoid growth carcinoma and nonpolypoid growth carcinoma, according to Shimoda et al.'s classification. RESULTS: Ten of 11 cases with MSI had a 1-base pair deletion in a polyadenine tract in the TGF beta RII gene. Fifteen cases showed polypoid growth and 30 cases indicated nonpolypoid growth. There were 9 polypoid growth cases and 2 nonpolypoid growth cases with MSI, while there were 6 polypoid growth cases and 28 nonpolypoid growth cases without MSI. Colorectal cancer cases with MSI had a significantly higher incidence of cases with polypoid growth (9/11) compared to those without MSI (6/34) (P = 0.0004). CONCLUSIONS: Sporadic colorectal carcinomas with MSI tend to show a polypoid growth type. We think that there are two types including "adenoma-carcinoma sequence" type and "RER" type in colorectal carcinomas that show adenoma-carcinoma progression.

Adult↗