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T Tsurumi

Publications and source records attributed to T Tsurumi.

At least 55 records · Page 3Linked to original sources
PubMed1993

The pathogenicity of a US3 protein kinase-deficient mutant of herpes simplex virus type 2 in mice.

We have investigated the pathogenicity of a US3 protein kinase-deficient mutant (L1 BR1) of herpes simplex virus type 2 (HSV-2) for 4-week-old ICR mice to define the role of the viral protein kinase in virus-host interaction. When mice were intraperitoneally infected with 10(5)PFU of L1 BR1, the virus disappeared from the peritoneal cavity by 2 days postinfection and failed to induce any significant histopathological changes in the liver and spleen although viral antigens were occasionally detected in the epithelial cells of small bile ducts and small vascular wall. The parental virus (HSV-2 186) and a revertant of the mutant (L1 B-11) both caused severe hepatitis, and viral antigens were clearly detected in the hepatocytes and Kupffer cells in the focal necrotic areas. Both of the virulent viruses, unlike L1 BR1, could produce infectious progeny and cytopathic effects in freshly harvested peritoneal macrophages. The growth of L1 BR1 in peritoneal macrophages was restricted at a stage of or prior to viral DNA synthesis but after the induction of viral DNA polymerase. In addition, the production and/or the spread of mutant in mouse embryo fibroblasts (MEF) was found to be much more effectively suppressed by cocultivation of peritoneal macrophages than that of 186. An almost complete inhibition of L1 BR1-plaque formation was observed at a macrophage-to-MEF ratio of 4:1. These results suggest that the attenuation of L1 BR1 following intraperitoneal infection is primarily due to its high sensitivity to intrinsic and extrinsic inhibition of peritoneal macrophages and that the US3 protein kinase may play a role in viral DNA replication in peritoneal macrophages.

Animals↗
PubMed1993

Functional interaction between Epstein-Barr virus DNA polymerase catalytic subunit and its accessory subunit in vitro.

The Epstein-Barr virus (EBV) DNA polymerase catalytic subunit (BALF5 protein) and its accessory subunit (BMRF1 protein) have been independently overexpressed and purified (T. Tsurumi, A. Kobayashi, K. Tamai, T. Daikoku, R. Kurachi, and Y. Nishiyama, J. Virol. 67:4651-4658, 1993; T. Tsurumi, J. Virol. 67:1681-1687, 1993). In an investigation of the molecular basis of protein-protein interactions between the subunits of the EBV DNA polymerase holoenzyme, we compared the DNA polymerase activity catalyzed by the BALF5 protein in the presence or absence of the BMRF1 polymerase accessory subunit in vitro. The DNA polymerase activity of the BALF5 polymerase catalytic subunit alone was sensitive to high ionic strength on an activated DNA template (80% inhibition at 100 mM ammonium sulfate). Addition of the polymerase accessory subunit to the reaction greatly enhanced DNA polymerase activity in the presence of high concentrations of ammonium sulfate (10-fold stimulation at 100 mM ammonium sulfate). Optimal stimulation was obtained when the molar ratio of BMRF1 protein to BALF5 protein was 2 or more. The DNA polymerase activity of the BALF5 protein along with the BMRF1 protein was neutralized by a monoclonal antibody to the BMRF1 protein, whereas that of the BALF5 protein alone was not, suggesting a specific interaction between the BALF5 protein and the BMRF1 protein in the reaction. The processivity of nucleotide polymerization of the BALF5 polymerase catalytic subunit on singly primed M13 single-stranded DNA circles was low (approximately 50 nucleotides). Addition of the BMRF1 polymerase accessory subunit resulted in a strikingly high processive mode of deoxynucleotide polymerization (> 7,200 nucleotides). These findings strongly suggest that the BMRF1 polymerase accessory subunit stabilizes interaction between the EBV DNA polymerase and primer template and functions as a sliding clamp at the growing 3'-OH end of the primer terminus to increase the processivity of polymerization.

Ammonium Sulfate↗
PubMed1993

Purification and characterization of the DNA-binding activity of the Epstein-Barr virus DNA polymerase accessory protein BMRF1 gene products, as expressed in insect cells by using the baculovirus system.

A recombinant baculovirus containing the complete sequence for the Epstein-Barr virus (EBV) BMRF1 gene product, the EBV DNA polymerase accessory protein, under the control of the polyhedrin promoter was constructed. Insect cells infected with the recombinant virus produced two phosphoproteins of 52 and 50 kDa and one unphosphorylated protein of 48 kDa, recognized by anti-BMRF1 protein-specific monoclonal antibody. The major protein bands were 50 and 48 kDa. The expressed BMRF1 gene products were purified to near homogeneity from the nuclear extract of the recombinant baculovirus-infected insect cells by double-stranded DNA-cellulose column chromatography followed by heparin-agarose column chromatography. The purified BMRF1 gene products exhibited higher binding affinity for double-stranded DNA than for single-stranded DNA without ATP hydrolysis. The protein-DNA interaction did not necessarily require a primer terminus. The present system will open the way for the biochemical characterization of the EBV DNA polymerase accessory protein.

Animals↗
PubMed1993

Functional expression and characterization of the Epstein-Barr virus DNA polymerase catalytic subunit.

A recombinant baculovirus containing the complete sequence for the Epstein-Barr virus (EBV) DNA polymerase catalytic subunit, BALF5 gene product, under the control of the baculovirus polyhedrin promoter was constructed. Insect cells infected with the recombinant virus produced a protein of 110 kDa, recognized by anti-BALF5 protein-specific polyclonal antibody. The expressed EBV DNA polymerase catalytic polypeptide was purified from the cytosolic fraction of the recombinant virus-infected insect cells. The purified protein exhibited both DNA polymerase and 3'-to-5' exonuclease activities, which were neutralized by the anti-BALF5 protein-specific antibody. These results indicate that the 3'-to-5' exonuclease activity associated with the EBV DNA polymerase (T. Tsurumi, Virology 182:376-381, 1991) is an inherent feature of the polymerase catalytic polypeptide. The DNA polymerase and the exonuclease activities of the EBV DNA polymerase catalytic subunit were sensitive to ammonium sulfate in contrast to those of the polymerase complex purified from EBV-producing lymphoblastoid cells, which were stimulated by salt. Furthermore, the template-primer preference for the polymerase catalytic subunit was different from that for the polymerase complex. These observations strongly suggest that the presence of EBV DNA polymerase accessory protein, BMRF1 gene product, does influence the enzymatic properties of EBV DNA polymerase catalytic subunit.

Ammonium Sulfate↗
PubMed1992

Relationship between tumor DNA ploidy and regional lymph node changes in lung cancer.

Seventy-four patients with lung cancer, resected consecutively from April 1989 to August 1990, were divided into (1) 21 with diploid tumors having a single G0/G1 peak and a coefficient of variation (CV) of 4.9 or less, (2) 18 with peridiploid tumors having a single G0/G1 peak and a CV at 5.0 or more, and (3) 35 with aneuploid tumors having multiple G0/G1 peaks. Aneuploid tumors had higher frequencies of lymphatic invasion and metastasis to the mediastinal lymph nodes. To evaluate the relationship between ploidy tumor status and immunologic competence of the regional lymph nodes, histologic findings and the proportion of killer T-lymphocytes were examined in the dissected lymph nodes. Aneuploid tumors had significantly lower proportions of paracortical hyperplasia and killer T-lymphocytes than did diploid and peridiploid ones in the nonmetastatic lymph nodes of N0 and N1 disease. These findings suggest the possibility that a decline in the antitumor competence of these lymph nodes could cause metastasis to the nodes. The recurrence rates were 19% in diploid, 33% in peridiploid, and 54% in aneuploid tumors, and the 2-year survival rates were 87%, 78%, and 44%, respectively. Peridiploid tumors showed intermediate values between diploid and aneuploid in terms of immunologic competence, recurrence rate, and survival. They were assumed to have a different proportion of aneuploid cells than the other two.

Aged↗
PubMed1992

Selective inhibition of the 3'-to-5' exonuclease activity associated with Epstein-Barr virus DNA polymerase by ribonucleoside 5'-monophosphates.

Epstein-Barr virus (EBV) DNA polymerase possesses a proofreading 3'-to-5' exonuclease activity (Tsurumi, T. (1991) Virology 182, 376-381). The 3'-to-5' exonuclease activity can be selectively inhibited by ribonucleoside 5'-monophosphates, while no inhibition of the DNA polymerase activity can be observed even when the template/primer concentrations are rate-limiting. Deoxynucleoside monophosphates except 5'dGMP have almost no effect on the exonuclease activity. Of the four ribonucleoside monophosphates, 5'GMP is the most potent (62% inhibition at 5 mM). The kinetic study shows that 5'-GMP inhibits the exonuclease activity competitively with respect to DNA template/primer. During DNA polymerization process the EBV DNA polymerase catalyzes the DNA-dependent conversion of complementary deoxynucleoside triphosphate to monophosphate form. With poly(dT).oligo(rA) as a template primer, selective inhibition of the exonuclease activity by 5'-GMP results in a decrease in the amount of free dAMP generated which is complementary to the template DNA, suggesting the functional relationship between the editing exonuclease activity and the chain elongation activity of the EBV DNA polymerase molecule.

Escherichia coli↗
PubMed1992

[Operation of pleural dissemination of thymoma].

Nine patients underwent operation for pleural dissemination of thymoma and received radiotherapy postoperatively. In 5 patients dissemination was resected along with the invasive thymoma at the initial operation. In 6 patients resection of a part of the diaphragm was needed. In 4 patients recurrent dissemination of thymoma appeared in the phrenico-costal sinus, where not only the location of dissemination but also postoperative radiotherapy had not been performed properly at the time of the previous operation. Seven are alive 2 months to 7 years 10 months after the first operation for dissemination. Two died respectively 7 years and 3 years 5 months after the first operation for dissemination.

Adult↗
PubMed1991

Primer terminus recognition and highly processive replication by Epstein-Barr virus DNA polymerase.

The Epstein-Barr virus (EBV) DNA polymerase is essential for viral DNA replication in the lytic phase of the EBV life cycle. It efficiently extends RNA primers on the template DNA, suggesting the possible involvement of the EBV DNA polymerase in synthesizing Okazaki fragments from RNA primers on the lagging strand template. Competition experiments revealed that the EBV DNA polymerase had significantly higher affinity for primer termini hybridized to the template DNA than for the single-stranded DNA template or the single-stranded primer itself. ATP was not required either for primer terminus recognition or for sustainment of polymerization. The stimulation of the enzyme by (NH4)2SO4 was dependent on the template/primers utilized. These observations suggest that the primary and secondary structure of the template/primers are important factors for primer terminus recognition by the EBV DNA polymerase. The enzyme elongated synthetic RNA primer annealed to circular single-stranded M13 DNA coated with Escherichia coli single-stranded DNA-binding protein without dissociation. The processivity of the EBV DNA polymerase was strikingly high (greater than 7200 nucleotides) and the rate of polymerization was 12 nucleotides/s per polymerase molecule. The high processing capacity is a desirable feature in the synthesis of multiple copies of the EBV genome in rolling-circle DNA replication.

Adenosine Triphosphate↗
PubMed1991

Prognostic implications of DNA histogram, DNA content, and histologic changes of regional lymph nodes in patients with lung cancer.

Forty-six cases of resected lung cancer, including 20 cases at Stages I and II and 26 cases at Stage III (N2), were subdivided into two groups: a good prognosis group with a longer survival period and a poor prognosis group in which the patients died earlier of the cancer. From paraffin-embedded lymph node tissues of these patients, the authors examined DNA histogram pattern and DNA content, using flow cytometry, and histologic hyperplasia of germinal center and paracortical area; they also evaluated their correlation with the prognosis. In the good prognosis group at Stages I and II, paracortical hyperplasia (PH) of the lymph nodes was observed significantly more frequently. In the good prognosis group at Stage III, the incidence of PH, G2M phase in the DNA histograms, and DNA content were all significantly higher. DNA content was positively correlated with the grade of PH.

Adenocarcinoma↗
PubMed1991

Characterization of 3'-to 5'-exonuclease activity associated with Epstein-Barr virus DNA polymerase.

Epstein-Barr virus (EBV) DNA polymerase mediates viral DNA replication during the lytic phase of the EB virus life cycle. In order to characterize its enzymatic activities EBV DNA polymerase was purified more than 1200-fold from chemically induced B95-8 cells. One polypeptide with molecular weight of 110,000 corresponded to the predicted EBV DNA polymerase, whereas the other polypeptides did not. A 3'-to-5' exonuclease activity was copurified with the EBV DNA polymerase through the course of the purification. Unlike HSV DNA DNA polymerase, 5'-to-3' exonuclease activity was not associated with the EBV DNA polymerase on the final step chromatography of single-stranded DNA agarose column. The associated 3'-to-5' exonuclease activity was stimulated by ammonium sulfate like the polymerase activity. It exhibited DNA-dependent nucleotide turnover activity and preferentially excised a terminal mismatched nucleotide on hybridized polynucleotides compared to the correctly paired substrate, indicating that the 3'-to-5' exonuclease may play a role in proofreading in the polymerization process.

Ammonium Sulfate↗
PubMed1990

An attempt to prepare hepatitis B virus (HBV)-free plasma by ultrafiltration using microporous regenerated cellulose hollow fiber.

Hepatitis B virus (HBV) can be effectively removed from HBV-positive plasma by filtration with a Bemberg Microporous Membrane (BMM) with a pore size of 30 nm or less, however considerable amounts of macromolecular IgM and Factor VIII are trapped in the BMM. We report that HBV-free plasma with adequate amounts of all of the plasma proteins can be obtained by double filtration with a BMM with a port size of 50 nm. Thus it may be possible to remove HBV or other transfusion-associated viruses from plasma by BMM filtration with good recovery of all of the plasma components.

Blood Proteins↗
PubMed1990

Release of RNA polymerase from vero cell mitochondria after herpes simplex virus type 1 infection.

Infection of Vero cells with herpes simplex virus type 1 results in the appearance in soluble extracts of a DNA primase activity. The partially purified enzyme, Mr, approximately 100,000, is identical in resistance to alpha-amanitin, pH profile, Mg2+ dependence, salt sensitivity, and KmATP to the catalytic core of Vero cell mitochondrial RNA polymerase. Moreover, the products synthesized are those expected of an RNA polymerase rather than a DNA primase. Inasmuch as the enzyme is not present in soluble extracts of uninfected Vero cells, we presume that the specific appearance of RNA polymerase in extracts of herpesvirus-infected cells results from infection-induced disruption of the mitochondrial membrane, followed by release of the enzyme into the cytosol.

Animals↗
PubMed1990

[Surgical treatment of bullous emphysema using Gore-Tex sheet].

Surgical treatment for bullous emphysema using Gore-Tex sheet and mechanical stapler is reported. The techniques were followed in a Juetnner's report: Small cut is made at the center of a 10 cm square of a Gore-Tex sheet, through which the area of bullous lung planned for resection is tented out with a lung forceps. A stapling instrument charged with a 4.8 mm clips is placed over the sheet around the suture line, and closed over both sheet and lung parenchyma. The excess sheet is removed after resection of the bullous lung. Five cases of bullous emphysema with a history of pneumothorax were successfully treated by the above method. Air leakage disappeared on the first postoperative day at latest. We assume Gore-Tex sheet, although a non-absorbable material, is in use as well as polydioxanone ribbon for prevention of air leakage in surgical cases of bullous emphysema.

Adult↗
PubMed1989

Herpes simplex virus 1 helicase-primase: a complex of three herpes-encoded gene products.

In an earlier report, we described a DNA helicase that is specifically induced upon infection of Vero cells with herpes simplex virus 1. We have purified this enzyme to near homogeneity and found it to consist of three polypeptides with molecular weights of 120,000, 97,000, and 70,000. Immunochemical analysis has shown these polypeptides to be the products of three of the genes UL52, UL5, and UL8 that are required for replication of a plasmid containing a herpes simplex 1 origin (oriS). In addition to helicase activity, the enzyme contains a tightly associated DNA primase. Thus, the three-subunit enzyme is a helicase-primase complex that may prime lagging-strand synthesis as it unwinds DNA at the viral replication fork.

Adenosine Triphosphatases↗
PubMed1989

A novel method for removal of human immunodeficiency virus: filtration with porous polymeric membranes.

We propose a new method to rid solutions of a virus by using a novel regenerated multilayered structured cellulose membrane (BMM). When the filtrate of human immunodeficiency virus (HIV) preparation was obtained through BMM it showed no infectivity. Electron microscopic observation revealed that HIV was completely caught by the multilayers of the BMM. Conveniently, BMM was seldomly found to adsorb protein molecules and also to have a high filtration rate. These characteristics may have a use in the removal of other variously sized pathogenic agents from plasma.

Cells, Cultured↗
PubMed1989

[A case of pulmonary infarction secondary to subacute bacterial endocarditis with subpulmonary VSD].

A case of pulmonary infarction secondary to subacute bacterial endocarditis of pulmonary valve which is associated with subpulmonary VSD is presented. The jet stream of blood through the subpulmonary VSD made damage to the pulmonary valve, which may be one of the reasons why subacute bacterial endocarditis was associated with the subpulmonary VSD. Echocardiography of the right-sided valves will be very useful in order to detect the pulmonary valve endocarditis in congenital heart disease presenting with fever.

Adult↗
PubMed1988

Interactions between UFT and anticoagulants in lung cancer patients.

In order to study the interactions between UFT and anticoagulants, the plasma and tissue concentrations of 5-FU, uracil and FT-207 were examined in patients with lung cancer. Higher plasma concentrations of 5-FU and uracil were observed in the patients who were given warfarin and ticlopidine beforehand, whereas the concentrations of FT-207 were almost the same in the patients who were given anticoagulants as in those who were not. This may be interpreted as an inhibition of dihydrouracil dehydrogenase, the common metabolizing enzyme of 5-FU and uracil, by anticoagulants. With regard to the tissue concentrations, higher levels of 5-FU and uracil in the tumor and lymph nodes were obtained after anticoagulants were given beforehand. Concentrations of FT-207 in these tissues, however, were almost the same in the patients who were given anticoagulants as in those who were not. We thus concluded that an increase of 5-FU in tumor cells and lymph nodes can be achieved after elevating the plasma concentrations of ordinary oral doses of UFT by using anticoagulation therapy beforehand.

Aged↗