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Biomedical subjects

S Nakada

Publications and source records attributed to S Nakada.

At least 19 recordsLinked to original sources
PubMed1996

Inhibition of influenza virus RNA polymerase and nucleoprotein genes expression by unmodified, phosphorothioated, and liposomally encapsulated oligonucleotides.

We have demonstrated that antisense phosphodiester (ODNs) and phosphorothioate oligonucleotides (S-ODNs) inhibit CAT (chloramphenicol acetyltransferase) protein expression in the clone 76 cell line, which is a derivative of the murine C127 cell line. This cell line expresses the influenza virus RNA polymerase and nucleoprotein (NP) genes in response to treatment with dexamethasone. Phosphodiester, phosphorothioate, and liposomally encapsulated oligonucleotides with four target sites (PB1, PB2, PA, and NP) were synthesized and tested for inhibitory effects by a CAT-ELISA assay using the clone 76 cell line. The ODNs and S-ODNs complementary to the sites of the PB2-AUG and PA-AUG initiation codons showed highly inhibitory effects. On the other hand, the inhibitory effect of the S-ODNs targeted to PB1 was considerably decreased in comparison with the other three target sites. Liposome encapsulation afforded oligomer protection in serum-containing medium and substantially improved cellular accumulation. The liposomal encapsulated oligonucleotides exhibited higher inhibitory activity than the free oligonucleotides. The activities of the unmodified oligonucleotides are effectively enhanced by using the liposomal carrier.

Animals↗
PubMed1996

Molecular dissection of influenza virus RNA polymerase: PB1 subunit alone is able to catalyze RNA synthesis.

Influenza virus RNA polymerase with the subunit structure PB1-PB2-PA is involved in both transcription and replication of the RNA genome. Enzyme reconstitution experiments indicated that all three P proteins are required for RNA synthesis in vitro (Kobayashi, et al. Virus Res 22, 235-245, 1992). Nuclear extracts of HeLa cells infected with three kinds of the recombinant vaccinia virus, each carrying one of the three P protein cDNAs, exhibited the activity of complete replication, that is, vRNA-sense RNA-directed and cRNA-sense RNA-directed RNA synthesis in the absence of primers. The nuclear extract from cells singly infected with the virus carrying PB1 cDNA exhibited a significant level of model v-sense RNA-directed RNA synthesis activity. Thus we conclude that PB1 is the catalytic subunit of influenza virus RNA polymerase and that under certain conditions, PB1 alone is able to catalyze RNA synthesis in vitro.

Base Sequence↗
PubMed1996

Immunoassay and immunohistology studies of chromogranin A as a neuroendocrine marker in patients with carcinoma of the prostate.

OBJECTIVES: Neuroendocrine differentiation in carcinoma of the prostate is characterized by the expression of neuroendocrine cell products such as chromogranin A (CgA). We studied serum levels and tissue staining for CgA in prostate cancer to assess their clinical value. METHODS: In 82 patients with prostate cancer, serum specimens were obtained at diagnosis and studied by both CgA and prostate-specific antigen (PSA) immunoassays. In 43 additional patients with prostate cancer, paraffin-embedded tissue from core biopsies or transurethral resections and serum samples were studied, respectively, by immunohistology and immunoassay for CgA. RESULTS: In serum samples from the 82 patients in whom CgA and PSA levels were measured, 26 of 82 (32%) had an elevated CgA (greater than 200 ng/mL), and 36 of 82 (44%) had an elevated PSA (greater than 4.0 ng/mL). Of the patients with Stage D2 cancer, 11 of 18 (61%) had an elevated CgA and 6 of 18 (33%) had an elevated PSA. Four of 5 patients with local recurrence had an elevated CgA, but only 1 patient had an elevated PSA. Of the 43 patients in whom serum and tissue CgA studies were performed, 12 (28%) had elevated serum CgA, and 15 of the 43 (35%) had CgA staining in their prostate tissue. Of the 14 of these patients with D2 disease (distant metastases), 9 (64%) had elevated serum levels of CgA and 6 (43%) had positive staining in their prostate tissue. Of the 9 patients with Stage D2 disease and elevated serum CgA, 6 had a normal serum PSA. CONCLUSIONS: Our studies complement those of others and indicate that CgA has potential as a clinically useful serum and tumor marker for prostate cancer. Serum CgA measurements can identify some patients with advanced disease who do not have elevated serum PSA. However, further studies in larger groups of patients are needed to define the clinical value of CgA as a marker for prostate cancer.

Biomarkers, Tumor↗
PubMed1996

Laparoscopic complications in markedly obese urologic patients (a multi-institutional review)

OBJECTIVES: Significant obesity is considered to be a relative contraindication to laparoscopic surgery. This study reviews the complications encountered in massively obese patients undergoing urologic laparoscopic surgery. METHODS: Body mass index (BMI) was used as an objective index to indicate massive obesity. Eleven institutions compiled retrospective data on 125 patients having a BMI greater than 30. Procedures performed included 76 pelvic lymph node dissections, 14 nephrectomies, 7 bladder neck suspensions, and 28 miscellaneous procedures. RESULTS: For the group as a whole, the mean BMI was 35.1 (range 30.1 to 57.2). Mean operative time was 202 minutes (range 60 to 480). Conversion to open surgery occurred in 15 of the 125 patients (12%). Complication rates (minor and major) were 22% (27 occurrences in 125 patients) intraoperatively and 26% (33 occurrences in 125 patients) postoperatively. The major complications included 2 trocar injuries to abdominal wall vessels, 1 bladder injury, 3 peripheral nerve injuries, 1 dysrhythmia, 1 deep vein thrombosis, 1 wound seroma, 1 nephrocutaneous fistula, 1 incisional hernia, and 1 death. CONCLUSIONS: In this review, complication rates for urologic laparoscopic surgery on massively obese patients were higher than in the general population undergoing laparoscopic surgery (0.3% to 21%).

Adolescent↗
PubMed1996

Herbimycin A down-regulates messages of cyclin D1 and c-myc during erythroid differentiation of K562 cells.

The ansamycin antibiotic, herbimycin A, is a potent tyrosine kinase inhibitor, and induces the erythroid differentiation of bcr-abl-possessing K562 cells. The growth of K562 cells was cytostatically reduced to less than 50% of the control level at 48 h by 0.5 microgram/ml of herbimycin A treatment. A total of 12% and 53% of the treated cells were benzidine-positive at 24 h and 48 h, respectively. The percentage of cells in the S phase decreased rapidly from 60% to 15% after 12 h of treatment. The reduction of S phase cells persisted until 24 h, whereas the G1 population conversely increased. Then underphosphorylated retinoblastoma gene product increased from 6 h to 24 h, but returned to baseline at 48 h. Most cell cycle controlling genes were unchanged by herbimycin A treatment. However, both cyclin D1 and c-myc were prominently down-regulated in the early phase of treatment, corresponding to the decline of the S phase population. Cyclin D1 was initially down-regulated to an undetectable level at 6 h, although its expression recovered gradually from 12 h and returned to baseline at 24 h. c-myc was also down-regulated from 1 h to 6 h. These data suggest that signals originating from bcr-abl kinase are at least partly transduced through both c-myc and cyclin D1, and that herbimycin A-induced erythroid differentiation occurs during or after the cessation of growth due to interference with these signals.

Antibiotics, Antineoplastic↗
PubMed1996

The PB1 subunit alone can catalyze cRNA synthesis, and the PA subunit in addition to the PB1 subunit is required for viral RNA synthesis in replication of the influenza virus genome.

We indicated that the PB1 and PA subunits of RNA polymerase and nucleoprotein (NP) can support replication of the influenza virus genome as well as transcription to yield uncapped poly(A)(+)-RNA (Y. Nakagawa, N. Kimura, T. Toyoda, K. Mizumoto, A. Ishihama, K. Oda, and S. Nakada, J. Virol. 69:728-733, 1995). To analyze the functions of the PB1 and PA subunits in replication and transcription, YP1N clones in which the PB1 and NP genes can be expressed in response to dexamethasone were established. cRNA was transcribed from model viral RNA (vRNA), but vRNA synthesis from model cRNA was not detected in YP1N clones. Furthermore, poly(A)(+)-RNA directed from model vRNA was synthesized in YP1N clones. These results indicated that PB1 and NP can support the syntheses of cRNA and poly(A)(+)-RNA and that the PA subunit, in addition to that of PB1 and to NP, is required for vRNA synthesis. In summary, the PB1 subunit is involved in the catalytic activities of nucleotide elongation, and the PA subunit may act as an allosteric modulator and cause a conformational change from a cRNA-to a vRNA-synthesizing form of the PB1 subunit.

Animals↗
PubMed1996

Quality of life and anxiety before and after lung cancer chemotherapy: relationship to patient's personality.

The purpose of the study was to assess the quality of life (QOL) and anxiety in 50 inpatients with primary lung cancer and examine the influence of their personalities on the QOL assessment. We used a psychological personality test to evaluate the patient's personality, then followed the course of QOL and anxiety before and after chemotherapy. To measure QOL, we used Holmes's QOL checklist, and the State-Trait Anxiety Inventory was adopted to estimate the patient's anxiety. Eighty courses of chemotherapy were administered, and QOL evaluations were performed 235 times. By using factor analysis, the somatic, social and psychological factors were extracted which confirmed the reliability and validity of the QOL checklist. The psychological QOL score showed a correlation with A (Adult) and AC (Adapted Child) of the five ego states in the Egogram. Therefore, it is important to survey the patients' personalities in order to grasp their QOL accurately.

Adult↗
PubMed1995

Interferon modulates the messenger RNA of G1-controlling genes to suppress the G1-to-S transition in Daudi cells.

Interferon (IFN) is one of the potent antiproliferative cytokines and is used to treat some selected cancers. IFN arrests the growth of Burkitt Lymphoma derived cell line Daudi cells in the G1 phase. G1-to-S progression is controlled by positive and negative regulatory genes. Therefore, we investigated the effects of IFN on G1-controlling genes. Expression of cyclin-dependent kinases (Cdks 2, 3, 4, 5, 6), MO15/Cdk7, and cyclins E and H was studied to assess positive regulators, while p15Ink4B, p16Ink4, p18, p21Cip1, and p27Kip1 were assessed as negative regulators. Cdks 2, 4, 6 and cyclin E were markedly down-regulated. MO15/Cdk7 expression showed little change, but its regulatory subunit (cyclin H) was down-regulated like cyclin E. Expression of p15Ink4B and p16Ink4 was not observed. p18 was induced until 48 h and its expression returned to the initial level at 72 h. In contrast, p21Cip1 mRNA expression remained at the baseline level throughout IFN treatment, while the expression of p27Kip1 increased at 48 and 72 h. Taken together, these data indicate that IFN changes the messenger RNA of G1-controlling genes towards the suppression of G1-to-S transition.

Base Sequence↗
PubMed1995

A macrolide antibiotic, roxithromycin, inhibits the growth of human myeloid leukemia HL60 cells by producing multinucleate cells.

The antiproliferative effect of roxithromycin (RXM) was studied using human myeloid leukemia HL60 cells. RXM inhibited the growth of HL60 cells in a concentration-dependent manner, and significantly inhibited growth at concentrations above 75 microM. This growth inhibition was not associated with specific cell cycle arrest and DNA synthesis was not impaired. In addition, the number of viable cells remained almost unchanged in the presence of 100 microM RXM. RXM induced growth inhibition at least partly by the formation of multinucleate cells. Both flowcytometric and morphological examination revealed that more than 40% of the RXM-treated cells were binucleate. These findings demonstrate that RXM is a potent new modulator of cell cycle progression in HL60 cells and suggest that the inhibition of cytokinesis by this drug may provide a new model for studying mitosis.

Bromodeoxyuridine↗
PubMed1995

The RNA polymerase PB2 subunit is not required for replication of the influenza virus genome but is involved in capped mRNA synthesis.

An established cell line, clone 64, in which the expression of the RNA polymerase PB1 and PA subunit genes and the nucleoprotein (NP) gene but not the PB2 subunit gene of influenza virus can be induced by the addition of dexamethasone, was used to analyze the replication and transcription machineries of the influenza virus. Both NS-CATc and NS-CATv, the chimeric nonstructural protein chloramphenicol acetyltransferase (NS-CAT) RNAs in the sense and antisense orientations positioned between the 5'- and 3'-terminal sequences of influenza virus RNA segment 8 (the NS gene), respectively, can be transcribed into the corresponding complementary-strand RNA in clone 64 cells only when treated with dexamethasone. Although sense-strand poly(A)+ CAT RNA was detected in the dexamethasone-treated clone 64 cells transfected with NS-CATv RNA, CAT activity was not detected in these cells and the isolated poly(A)+ CAT RNA was inert in an in vitro translation system. However, when the poly(A)+ CAT RNA was capped by using a purified yeast mRNA capping enzyme (mRNA guanylyltransferase), the capped poly(A)+ CAT RNA became translatable in the in vitro translation system. These results indicated that PB1, PA, and NP can support the replication of the influenza virus genome as well as the transcription to yield uncapped poly(A)+ RNA and that PB2 is specifically required for the synthesis of capped RNA.

Animals↗
PubMed1995

[Transformation into chronic myelomonocytic leukemia in a patient with primary myelofibrosis associated with severe hypoplasia: report of an autopsy case].

A 70-year-old male was admitted because of anemia in September 1989, and primary myelofibrosis was diagnosed based on the presence of leukoerythroblastosis, a normal chromosomal analysis and pathological findings of fibrosis in bone marrow. Although he was anemic, he did not require any treatment for two years. Then his hematological status deteriorated to severe pancytopenia, and the marrow biopsy revealed marked hypoplasia with fatty replacement and scattered fibrosis. He was treated with metenolon without success and frequent transfusion of packed red cell was required. This hypoplastic status continued for seven months. In May 1992 his WBC count increased gradually with monocytosis. The marrow was filled with various stages of monocytes, with almost no fibrosis remaining. The chromosomal analysis was repeated but disclosed no abnormalities, consistent with the negative result of BCR-ABL rearrangement investigated by the RT-PCR method. One month later, when the patient died of multiple cerebral bleeding and infection, the leukocyte count exceed 90,000/microliters. It is known that major causes of death for patients with primary myelofibrosis are infection, bleeding, cardiac trouble and transformation to leukemia. We describe a case of myelofibrosis who developed to chronic myelomonocytic leukemia following severe aplastic phase.

Aged↗
PubMed1995

Inhibition of influenza virus RNA polymerase and nucleoprotein of gene expression by antisense oligonucleotides.

We demonstrated that unmodified and modified (phosphorothioate) antisense oligonucleotides inhibit CAT (chloramphenicol acetyltransferase) protein expression in the clone 76 cell line. This cell line expresses the influenza virus RNA polymerase and nucleoprotein (NP) genes in response to dexamethasone. Antisense oligonucleotides with four target sites (PB1, PB2, PA, and NP) were synthesized and tested for the their inhibitory effects by a CAT-ELISA assay. Antisense phosphorothioate oligonucleotides (S-ODNs) complementary to the sites of the PB2-AUG and PA-AUG initiation codons showed a high inhibitory effect. On the other hand, the inhibitory effect of the S-ODNs targeted to PB1 was considerably decreased in comparison with the other three target sites.

Base Sequence↗
PubMed1994

Regulation of influenza virus RNA polymerase activity by cellular and viral factors.

An in vitro RNA synthesis system mimicking replication of genomic influenza virus RNA was developed with nuclear extracts prepared from influenza virus-infected HeLa cells using exogenously added RNA templates. The RNA synthesizing activity was divided into two complementing fractions, i.e. the ribonucleoprotein (RNP) complexes and the fraction free of RNP, which could be replaced with RNP cores isolated from virions and nuclear extracts from uninfected cells, respectively. When nuclear extracts from uninfected cells were fractionated by phosphocellulose column chromatography, the stimulatory activity for RNA synthesis was further separated into two distinct fractions. One of them, tentatively designated RAF (RNA polymerase activating factor), stimulated RNA synthesis with either RNP cores or RNA polymerase and nucleocapsid protein purified from RNP cores as the enzyme source. In contrast, the other, designated PRF (polymerase regulating factor), functioned as an activator only when RNP cores were used as the enzyme source. Biochemical analyses revealed that PRF facilitates dissociation of RNA polymerase from RNP cores. Of interest is that virus-coded non-structural protein 1 (NS1), which has been thought to be involved in regulation of replication, counteracted PRF function. Roles of cellular factors and viral proteins, NS1 in particular, are discussed in terms of regulation of influenza virus RNA genome replication.

Biological Factors↗
PubMed1994

Changes of cell cycle-regulating genes in interferon-treated Daudi cells.

Interferon (IFN) modulates the expression of several genes and some of them are considered to be responsible for the inhibition of cellular growth. However, the alterations of cell cycle-regulating genes produced by IFN still remain unclear. Accordingly, we studied the expression of cell cycle-regulating genes during IFN-induced growth arrest. Cell cycle synchronized and unsynchronized Daudi Burkitt lymphoma cells were treated with IFN. Both the cell cycle distribution and the expression of cell cycle-regulating genes (cdk2, cdc2, cyclins A, B, C, D3, cdc25, and wee 1) were studied by flow cytometry and by Northern blot hybridization or the reverse-transcription polymerase chain reaction, respectively. Treated cells passed through the first G1 phase and gradually accumulated in the following G1 phase. Expression of cyclins A, B, and D3 oscillated along with the cell cycle progression in control cells, and the alterations of cyclin B expression were especially prominent. Both cdc2 and cdk2 also showed changes, but these were not so distinct as observed with cyclin B. Expression of cdc25 and wee1 was little affected by cell cycle progression. In IFN-treated cells, expression of cyclins A and B were down-regulated, while that of cyclin C was not. Cyclin D3 expression was also down-regulated at 48 h, followed by an increase at 72 h. Expression of both cdc2 and cdk2 was down-regulated, especially that of the later. Wee1 expression was down-regulated by IFN but, the expression of cdc25 remained stable. These findings suggest that the modulation of cell cycle-regulating genes, particular by cyclin A and cdk2, plays an important role in IFN-induced cellular growth arrest.

Base Sequence↗
PubMed1994

Changes of G1 cyclins, cdk2, and cyclin A during the differentiation of HL60 cells induced by TPA.

Differentiation induction by 12-o-tetradecanoyl 13-acetate (TPA) results in the growth arrest of HL60 cells in the G1 phase. However, little is known about the changes of cell cycle-regulating genes during this differentiation process. We investigated the changes of mRNA for various cyclins (A, C, D1, D2, D3 and E) and cdk2. Synchronized HL60 cells began to proliferate immediately after release from cell cycle block and cell cycle synchrony was obvious until the second S phase. TPA-treated cells accumulated in G1 phase within 24 h and most of the cells were arrested in this phase at 36 h. The expression of cyclins and cdk2 was studied by Northern blot hybridization of the reverse-transcription polymerase chain reaction (RT-PCR). TPA treatment altered the expression of all genes studied. The expression of cdk2 and cyclin A mRNA was markedly down-regulated. Cyclin E mRNA expression was also prominently down-regulated from 12 h to 36 h, at which time a second increase of its expression was observed in control cells. In contrast, the expression of cyclin D1 mRNA was induced by TPA, while its expression in control cells was undetectable by Northern blot hybridization throughout the cell cycle. Cyclin C expression was faint and fluctuated irrelevant of cell cycle, but its expression in both control and TPA-treated cells was higher than at baseline. Cyclin D2 expression remained stable in control cells and TPA treatment resulted in slight down-regulation at 12 h, but no difference was observed after 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1994

Influenza virus NS1 protein stimulates translation of the M1 protein.

The influenza virus NS1 protein was shown to stimulate translation of the M1 protein. M-CAT RNA, which contains the chloramphenicol acetyltransferase (CAT) reporter gene and the terminal noncoding sequence of segment 7 (coding for the M1 and M2 proteins), was ribonucleoprotein transfected into clone 76 cells expressing the influenza virus RNA polymerase and NP proteins required for the transcription and replication of influenza virus ribonucleoproteins. When the cells were superinfected with a recombinant vaccinia virus which expresses the NS1 protein, CAT expression from the M-CAT RNA was significantly stimulated but transcription was not altered. The expression of NS-CAT RNA, which contains noncoding sequences of segment 8 (coding for the NS1 and NS2 proteins), was not altered by the NS1 protein. Site-directed mutagenesis showed that the sequence GGUAGAUA upstream of the initiation codon on segment 7 was required for stimulation.

Base Sequence↗
PubMed1994

[Noninvasive evaluation of chronic cumulative and acute cardiotoxicity induced by anthracycline in children with acute leukemia. Assessment of mainly left ventricular contractile state by M mode echocardiography].

The cardiotoxic effects of Daunomycin (DM) ad Adriamycin (ADR), Anthracyclines (ATC), were studied mainly by echocardiography to evaluate their chronic cumulative cardiotoxicity and acute cardiotoxicity during consolidation therapy. Electrocardiographic findings were less sensitive and therefore less reliable for evaluation of the chronic cumulative cardiotoxicity and acute cardiotoxicity induced by ATCs during consolidation therapy. With echocardiography ESS/ESVI, the index of the left ventricular contraction, had the highest sensitivity among indices for cardiotoxicity. SF was useful for easy measurement and calculation of cardiotoxicity. Evaluation of the chronic cumulative cardiotoxicity of ATC drugs indicated that cumulative doses of 300 mg/m2 or more resulted in abnormally low ESS/ESVI levels suggesting cardiotoxicity in many cases, and doses of 500 mg/m2 or more caused abnormally low levels in all cases. Evaluation of acute cardiotoxicity showed that post-consolidation therapy ESS/ESVI levels were significantly lower than pre-consolidation therapy levels in the group treated with doses of 500 mg/m2 or more, but the condition was reversible except in those patients with heart failure. As for the relation between cumulative doses and cardiotoxicity, the indices studied showed no differences between DM and ADR. These results indicate that careful follow-up mainly by echocardiography is required after doses reaching 300 mg/m2 or more of ATC drugs.

Adolescent↗