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S Nishimura

Publications and source records attributed to S Nishimura.

At least 145 records · Page 8Linked to original sources
PubMed1999

Intercalation into DNA is not required for inhibition of topoisomerase I by indolocarbazole antitumor agents.

The DNA-intercalating antitumor drug NB-506 is a potent topoisomerase poison currently undergoing phase I/II clinical trials. It contains a planar indolocarbazole chromophore substituted with a glucose residue. Up until now, it was thought that intercalation of the drug into DNA was essential for the stabilization of topoisomerase I-DNA covalent complexes. But, in the present study, we show that a regio-isomeric form of NB-506 has lost its capacity to intercalate into DNA, but remains an extremely potent topoisomerase I poison. The new analogue contains two hydroxyl groups at positions 2,10 instead of positions 1,11 in NB-506. The relocation of the two OH groups reduces considerably the strength of binding to DNA and prevents the drug from intercalating into the DNA double helix. However, the topoisomerase I inhibition capacity of the new analogue remains very high. The two drug isomers are equally potent at maintaining the integrity of the topoisomerase I-DNA covalent complexes, but stimulate cleavage at different sites on DNA. NB-506 stabilizes topoisomerase I preferentially at sites having a pyrimidine (T or C) and a G on the 5' and 3' sides of the cleaved bond, respectively. The 2,10-isomer induces topoisomerase I-mediated cleavage only at TG sites and, thus, behaves exactly as the reference topoisomerase I poison camptothecin. Finally, cytotoxicity measurements performed with a panel of murine and human cancer cell lines reveal that the newly designed drug is considerably (up to 100-fold) more toxic to tumor cells than the parent drug NB-506. We conclude that the DNA-binding and topoisomerase I poisoning activities of NB-506 can be viewed as two separate mechanisms.

Animals↗
PubMed1999

A new mechanism of acquisition of drug resistance by partial duplication of topoisomerase I.

Topoisomerase (topo)-I targeting antitumor agents are very effective in vivo against various human cancers. The indolocarbazole compound 6-N-formylamino-12,13-dihydro-1,11-dihydroxy-13-(beta-D-glucopyranosyl)- 5H-indolo[2,3-alpha]pyrrolo-[3,4-c]carbazole-5,7(6H)-dione (NB-506) is a potent inhibitor of the religation step of topo I reaction, like camptothecin (CPT). We established a NB-506-resistant cell line from murine leukemia cell line P388. This resistant cell line, P388/F11, exhibited 73-fold higher resistance to NB-506 and 3.5-fold higher cross-resistance to CPT than the parental cell line. No induction of cleavable complex formations induced by NB-506 and CPT were detected by K-SDS precipitation assays in P388/F11 cells. Analysis of nuclear extracts from P388/F11 cells revealed that the relaxation activity of topo I was one-quarter of that of the parental cells, and that the activity was resistant to induction of DNA cleavage by these drugs. Furthermore, Western blot and Northern blot analyses showed the expression of an abnormal-sized 170-kDa topo I protein and its 6.0-kb transcript and the absence of the normal topo I protein and transcript in P388/F11 cells. Analyses of the structure of the abnormal topo I transcript by reverse transcription-PCR and direct sequencing methods revealed that a large portion of the gene from codon 21 to codon 609 was duplicated in its coding region. This internal duplication resulted in in-frame fusion and, thus, production of a partially duplicated protein of 1357 amino acids. Finally, we expressed and purified the recombinant P388/F11 topo I in a baculovirus system. P388/F11 topo I showed similar catalytic activity to wild-type topo I, but reduced sensitivities to NB-506 and CPT. These results show that the altered sensitivity of duplicated topo I is involved in the NB-506 resistance of P388/F11 cells and indicate a novel resistant mechanism which involves duplication of the topo I gene.

Animals↗
PubMed1999

Human MMH (OGG1) type 1a protein is a major enzyme for repair of 8-hydroxyguanine lesions in human cells.

8-Hydroxyguanine (8-OH-G) is the site of a frequent mutagenic lesion of DNA, produced by oxidative damage. MutM of E. coli and OGG1 of Saccharomyces cervisiae are known to possess 8-OH-G glycosylase activity and apurinic (AP) site lyase activity to repair 8-OH-G lesions. Recently, cDNA clones of human OGG1 homologues (hMMH) of four isoforms (type 1a, type 1b, type 1c, and type 2) were isolated. However, it is unknown whether expression of endogenous hMMH proteins actually occurs in mammalian cells. Here using hMMH type 1a-specific antibody and cells overexpressing tag-fused hMMH type 1a, we show the expression of hMMH type 1a protein in many types of human cells and show that endogenous hMMH type 1a protein has 8-OH-G glycosylase/AP lyase activity. Furthermore, we show that upon depletion of hMMH type 1a protein in a whole cell extract by its antibody, most of the AP lyase activity is lost, indicating that hMMH type 1a protein is a major enzyme for repair of 8-OH-G lesions in human cells.

Antibodies↗
PubMed1999

Synthesis and biological activities of topoisomerase I inhibitors, 6-N-amino analogues of NB-506.

6-N-Amino analogues of NB-506 [6-N-formylamino-12,13-dihydro-1,11-dihydroxy-13-(beta-D-glucopyranosyl) -5H-indolo[2,3-a]pyrrolo[3,4-c]carbazole-5,7(6H)-dione] (3b) were synthesized and tested with respect to topoisomerase inhibition, cytotoxicity and anticancer effects. Among them, a 1,3-dihydroxypropane analogue (J-109,404, 5t) showed more than ten times more potent anticancer activity in MKN-45 human stomach cancer cells implanted in mice than NB-506.

Animals↗
PubMed1999

The natural killer T (NKT) cell ligand alpha-galactosylceramide demonstrates its immunopotentiating effect by inducing interleukin (IL)-12 production by dendritic cells and IL-12 receptor expression on NKT cells.

The natural killer T (NKT) cell ligand alpha-galactosylceramide (alpha-GalCer) exhibits profound antitumor activities in vivo that resemble interleukin (IL)-12-mediated antitumor activities. Because of these similarities between the activities of alpha-GalCer and IL-12, we investigated the involvement of IL-12 in the activation of NKT cells by alpha-GalCer. We first established, using purified subsets of various lymphocyte populations, that alpha-GalCer selectively activates NKT cells for production of interferon (IFN)-gamma. Production of IFN-gamma by NKT cells in response to alpha-GalCer required IL-12 produced by dendritic cells (DCs) and direct contact between NKT cells and DCs through CD40/CD40 ligand interactions. Moreover, alpha-GalCer strongly induced the expression of IL-12 receptor on NKT cells from wild-type but not CD1(-/-) or Valpha14(-/-) mice. This effect of alpha-GalCer required the production of IFN-gamma by NKT cells and production of IL-12 by DCs. Finally, we showed that treatment of mice with suboptimal doses of alpha-GalCer together with suboptimal doses of IL-12 resulted in strongly enhanced natural killing activity and IFN-gamma production. Collectively, these findings indicate an important role for DC-produced IL-12 in the activation of NKT cells by alpha-GalCer and suggest that NKT cells may be able to condition DCs for subsequent immune responses. Our results also suggest a novel approach for immunotherapy of cancer.

Adjuvants, Immunologic↗
PubMed1999

New DNA polymorphisms of human MMH/OGG1 gene: prevalence of one polymorphism among lung-adenocarcinoma patients in Japanese.

MMH/OGG1 is an 8-hydroxyguanine-specific DNA glycosylase/AP-lyase, one of the mutator enzymes for the excision repair of 8-hydroxyguanine. DNA polymorphisms in human MMH/OGG1 gene were newly identified and analyzed to examine a possible association with lung-cancer risk by a population-based study. Polymorphic allele 3 in hMMH/OGG1 exon 1 was significantly prevalent among Japanese patients with adenocarcinoma of the lung [odds ratio (OR): 3.152, 95% confidence interval (CI): 1.266-7.845], indicating that the excision repair of 8-hydroxyguanine may play a role in predisposition to lung cancer.

Adenocarcinoma↗
PubMed1999

Modified nucleosides in the first positions of the anticodons of tRNA(Leu)4 and tRNA(Leu)5 from Escherichia coli.

Minor leucine tRNA species, tRNA(Leu)4 and tRNA(Leu)5, from Escherichia coli B have been reported to recognize leucine codons UUA and UUG [Goldman, E., Holmes, W. M., and Hatfield, G. W. (1979) J. Mol. Biol. 129, 567-585]. In the present study, these two tRNA(Leu) species were purified from E. coli A19, and the nucleotide sequences were determined by a post-labeling method. tRNA(Leu)5 was found to correspond to the tRNA gene reported as su degrees6 tRNA [Yoshimura, M., Inokuchi, H., and Ozeki, H. (1984) J. Mol. Biol. 177, 627-644]. The first letter of the anticodon was identified to be 2'-O-methylcytidine (Cm). tRNA(Leu)4 was identified as the minor leucine tRNA that has been sequenced previously (tRNA(Leu)UUR) [Yamaizumi, Z., Kuchino, Y., Harada, F., Nishimura, S., and McCloskey, J. A. (1980) J. Biol. Chem. 255, 2220-2225]. There was an unidentified modified nucleoside (N*) in the first position of the anticodon of tRNA(Leu)4. Nucleoside N* was isolated to homogeneity (1 A260 unit). By 1H NMR spectroscopy, nucleoside N was found to be a 2'-O-methyluridine derivative with a substituent having a -CH2NH2+CH2COO- moiety in position 5 of the uracil ring. On the basis of these NMR analyses together with mass spectrometry, the chemical structure of nucleoside N* was determined as 5-carboxymethylaminomethyl-2'-O-methyluridine (cmnm5Um). Nucleoside N* was thus found to be a novel type of naturally occurring modified uridine. Because of the conformational rigidity of Cm and cmnm5Um in the first position of the anticodon, these tRNA(Leu) species recognize the leucine codons UUA++ and UUG correctly, but never recognize the phenylalanine codons UUU and UUC.

Anticodon↗
PubMed1999

CMAP: a novel cystatin-like gene involved in liver metastasis.

A novel metastasis-associated gene was identified with a differential display system in murine carcinoma cells showing a high rate of metastasis to the liver. A human homologue was also identified using a PCR-based strategy. The protein coded by this gene was named cystatin-like metastasis-associated protein (CMAP) and showed 22.1-28.1% homology to human family 2 cystatins. CMAP mRNA was selectively overexpressed in all murine liver metastatic tumors but not in any pulmonary metastatic tumors examined. Transfection of CMAP antisense DNA into highly metastatic liver cells greatly decreased their metastatic potential and CMAP expression, indicating that CMAP is involved in liver metastatic ability after intravasation of malignant cells. The human homologue of CMAP was found to be expressed in various human cancer cell lines established from malignant tumors. Our discovery of this novel liver metastasis-related gene indicates a new approach to the diagnosis and/or prevention of liver metastasis of human cancer.

Amino Acid Sequence↗
PubMed1999

Cerebral blood-flow responses to induced hypotension and to CO2 inhalation in patients with major cerebral artery occlusive disease: a positron-emission tomography study.

Our aim was to study the relationship between cerebral blood flow (CBF) responses to induced hypotension and to CO2 inhalation in patients with occlusive disease of the carotid or middle cerebral arteries. In 13 patients (8 men, 5 women) aged 31-73 years (mean +/- 1 SD = 63.2 +/- 10.6), regional CBF values during the resting state (CBFrest), 7% CO2 inhalation (CBFhypercapnia), and hypotension induced by 10-20 microg/kg/min intravenous trimethaphan (CBFhypotension) were measured using positron-emission tomography (PET) with H2(15)O. The % CBF change during induced hypotension (% CBFhypotension) was defined as (CBFhypotension - CBFrest)/CBFrest multiplied by 100. The % CBF change during CO2 inhalation (% CBFhypercapnia) was defined as (CBFhypercapnia - CBFrest)/CBFrest/mm Hg arterial partial pressure of CO2 x 100. We defined symptomatic hemispheres as those with a stenotic or occlusive lesion with neurological symptoms or signs and asymptomatic hemispheres as those which had a similar lesion and/or were influenced by the collateral flow pattern without neurological symptoms. In the territory of the occlusive lesion, % CBFhypotension correlated significantly with % CBFhypercapnia (r = 0.793, P < 0.002) in the symptomatic hemispheres. In the brain regions in which trimethaphan did not induce a reduction in CBF. % CBFhypercapnia was 6.13 +/- 1.79. In those in which % CBFhypotension ranged from 0 to -5, from -5 to -10, and more than -10%, % CBFhypercapnia was 4.05 +/- 1.99, 3.21 +/- 1.17, and 1.73 +/- 1.61, respectively, with significant differences between each pair of groups. In the asymptomatic hemispheres, % CBFhypotension also correlated with % CBFhypercapnia (r = 0.979, P < 0.0001). Failure to maintain CBF during induced hypotension was associated with diminished cerebrovascular vasoreactivity to hypercapnia in patients with arterial disease. This may indicate that failure of autoregulation can be assessed by the CBF response to both induced hypotension and CO2 inhalation. From the technical point of view, estimation of the CO2 response may be useful for assessing failure of autoregulation.

Administration, Inhalation↗
PubMed1999

Experimental vaccine activities of recombinant E1 and E2 glycoproteins and hypervariable region 1 peptides of hepatitis C virus in chimpanzees.

A chimpanzee was immunized with two recombinant envelope glycoproteins E1 and E2 of hepatitis C virus (HCV), strain HCV-N2, and the hypervariable region 1 (HVR1) peptides of a different isolate, HCV-#6, then received an intravenous inoculation of 10 chimpanzee infectious doses of HCV-#6. With high humoral immune response against E1 and E2 but a low response against HVR1, the vaccinee became infected with the HCV. However, after increasing the titer of anti-HVR1 against HCV-#6, the vaccinee showed protection. Neutralization of HCV-#6 with the antiserum from this protected vaccinee was achieved by inoculation of this mixture into another chimpanzee. These results suggest that vaccination with a peptide-vaccine of homologous HVR1 is effective in the chimpanzee.

Amino Acid Sequence↗
PubMed1999

Effects of intensive lipid lowering by low-density lipoprotein apheresis on regression of coronary atherosclerosis in patients with familial hypercholesterolemia: Japan Low-density Lipoprotein Apheresis Coronary Atherosclerosis Prospective Study (L-CAPS).

Twenty-five heterozygous familial hypercholesterolemic patients treated with LDL-apheresis and drugs and 11 patients treated with drugs underwent follow-up angiography 2.3 years later. One-hundred thirteen lesions were measured by quantitative angiography. Mean LDL-cholesterol levels during the trial were 140 +/- 34 mg/dl in the apheresis group and 170 +/- 58 mg/dl (P < 0.05) in the control group. The mean changes in minimal lumen diameter of lesions were +0.19 +/- 0.30 mm (improved) in the apheresis group (n = 76) and -0.44 +/- 0.40 mm (worsened) in the control group (n = 37) (P < 0.0001). When progression and regression were defined as a change in minimal lumen diameter of +/- 0.67 mm, in the apheresis group, two (8%) patients had progression, 19 (76%) stayed unchanged and four (16%) had regression, but in the control group seven (64%) patients had progression and four (36%) stayed unchanged. The frequency of regression or no change was significantly higher in the apheresis group than in the control group (P < 0.004). Intensive cholesterol lowering therapy with LDL-apheresis and lipid lowering drugs can achieve a substantial decrease in LDL-cholesterol levels to induce regression of coronary lesions in familial hypercholesterolemic patients with advanced coronary artery disease.

Adult↗
PubMed1999

Identification and cloning of a novel isoform of mouse secretory leukocyte protease inhibitor, mSLPI-beta, overexpressed in murine leukemias and a highly liver metastatic tumor, IMC-HA1 cells.

Several genes showing transcriptional alteration in a highly liver metastatic murine carcinoma cell line, IMC-HA1, were identified by mRNA differential display system. Among them, a gene identical to mSLPI was isolated as mSLPI-alpha and -beta. They were produced through an alternative splicing. Their full-length cDNA sequences were determined, and their expression in various murine tumors and normal tissues was analysed. The deduced translation product of mSLPI-alpha showed 59% identity to hSLPI. Although mSLPI-beta had the same 103-amino-acid sequence from the carboxyl terminus, the amino terminus showed hydrophilicity opposite mSLPI-alpha or hSLPI. The mSLPI-alpha was expressed ubiquitously in various tumor cell lines. Interestingly, however, mSLPI-beta expression was only observed in P388 and L1210 leukemias and IMC-HA1 cells, and in lower amounts in three normal tissues (thymus, lung and spleen), suggesting that mSLPI, and in particular the unusual splicing product, mSLPI-beta, plays a specific role in these cells, including malignant processes of tumor cells.

Amino Acid Sequence↗
PubMed1999

Handwashing before entering the intensive care unit: what we learned from continuous video-camera surveillance.

Handwashing is one of the most important factors in controlling the spread of bacteria and in preventing the development of infections. This simple procedure does not have a high compliance rate. The Association for Professionals in Infection Control and Epidemiology, Inc, guideline recommends that hands must be washed before and after patient contact. In our intensive care unit (ICU), we have made it a rule that everyone should wash their hands before entering the ICU. The purpose of this study was to ascertain the handwashing compliance of all personnel and visitors to the ICU. A ceiling-mounted video camera connected to a time-lapse video cassette recorder recorded each person's actions when they entered the ICU during a 7-day period. Handwashing compliance was assessed for 3 different categories: ICU personnel, non-ICU personnel, and visitors to patients. There were 1030 entries to the ICU during the observation period. ICU personnel complied with handwashing in 71% of entries, non-ICU personnel in 74% of entries, and visitors to patients in 94% of entries. Handwashing compliance by visitors to patients was significantly higher than among personnel (P <.001). Handwashing compliance among personnel before entering the ICU was low. Continuous effort is needed to raise awareness of the handwashing issue, not only to ensure compliance with APIC recommendations but also in our facility, to ensure that health care personnel wash their hands on entry to the ICU.

Guideline Adherence↗
PubMed1999

BMIPP in angina pectoris.

Radionuclide imaging with BMIPP for assessment of myocardial metabolism can assist in clinical decision making in certain subsets of patients with coronary artery disease. In stable angina, abnormal BMIPP imaging and less BMIPP uptake than Tl-201 are more likely to be seen in the distribution of vessels with severe stenoses and related to regional wall abnormalities. BMIPP SPECT imaging is a promising approach in the evaluation of patients with suspected unstable angina during the pain-free period even after stabilization. Fatty acid metabolism is easily suppressed due to the abrupt onset of ischaemia. In addition, combined imaging with BMIPP and Tl-201 can provide insights into the understanding of abnormal metabolism in myocardium in stable and unstable angina. This review addressed the clinical applications of BMIPP imaging for evaluation of stable and unstable angina.

Angina Pectoris↗
PubMed1999

Intraoperative radiotherapy for the abdominal lymphatic system in patients with esophageal carcinoma.

We applied intraoperative radiotherapy (IORT) to the esophageal carcinoma in an attempt to prevent abdominal lymph node recurrence, and retrospectively studied patterns of failure and controllability of abdominal lymph nodes in patients treated with or without IORT. Between July 1986 and October 1997, 81 patients with radically resected esophageal carcinoma, aged 42-76 years (mean 61), were divided into two groups, the IORT group (39 patients) and the non-IORT group (42 patients). All patients except two, who received transhiatal esophagectomy for superficial carcinoma, underwent subtotal esophagectomy with thoracic and abdominal with/without cervical lymphadenectomy. Fourteen patients underwent only surgical resection, and the remaining 67 patients received radiotherapy to the mediastinum post-operatively (40-50 Gy/20-25 Fr/4-5 W) in 37 and preoperatively (44 Gy/40 Fr/4 W) in 30 patients. Preoperative irradiation was performed as a neoadjuvant chemoradiotherapy consisting of two courses of cisplatin (each patient received 80-100 mg, mean 60 mg m(-2), day 1, bolus injection) and 5-fluorouracil (each patient received 500-1000 mg day(-1), mean 400 mg m(-2), days 1-4, continuous infusion). The target volume of IORT encompassed the upper abdominal lymph node area including lymph node groups of right/left cardia, left gastric artery, celiac artery and abdominal para-aorta. A single dose of high-energy electrons (9-12 MeV) of 20-23 Gy, prescribed to the 90% isodose curve, was delivered. Treatment for the abdominal lymphatic system was classified into four categories: surgery alone in 30 patients, surgery with chemotherapy in 12, surgery with IORT in 15, surgery with chemotherapy and IORT in 24. There were no complications related to IORT. Forty patients (49%) had recurring carcinoma: in the lymph nodes (36%), in distant organs (27%) and locally (6%). The incidence of lymph node metastasis was 29% in the neck, 32% in the mediastinum, and 27% in the abdomen. Abdominal lymph node recurrence in the IORT group was less frequent than in the non-IORT group (p=0.048). In particular, 24 patients treated with a combination of surgery, chemotherapy and IORT had no recurrence in the abdominal lymphatic system. The overall median survival was 46 months, the survival at 1, 3, and 5 years being 85%, 52%, and 44% respectively. However, there was no difference in survival between the IORT group and the non-IORT group. The IORT for the abdominal lymphatic system was feasible for reduction of the rate of abdominal lymphatic recurrence without survival benefit in this study. This retrospective finding should be confirmed by a prospective randomized study.

Adult↗
PubMed1999

Allyl-containing sulfides in garlic increase uncoupling protein content in brown adipose tissue, and noradrenaline and adrenaline secretion in rats.

The effects of garlic supplementation on triglyceride metabolism were investigated by measurements of the degree of thermogenesis in interscapular brown adipose tissue (IBAT), and noradrenaline and adrenaline secretion in rats fed two types of dietary fat. In Experiment 1, rats were given isoenergetic high-fat diets containing either shortening or lard with or without garlic powder supplementation (8 g/kg of diet). After 28 d feeding, body weight, plasma triglyceride levels and the weights of perirenal adipose tissue and epididymal fat pad were significantly lower in rats fed diets supplemented with garlic powder than in those fed diets without garlic powder. The content of mitochondrial protein and uncoupling protein (UCP) in IBAT, and urinary noradrenaline and adrenaline excretion were significantly greater in rats fed a lard diet with garlic powder than in those fed the same diet without garlic. Other than adrenaline secretion, differences due to garlic were significant in rats fed shortening, also. In Experiment 2, the effects of various allyl-containing sulfides present in garlic on noradrenaline and adrenaline secretion were evaluated. Administration of diallyldisulfide, diallyltrisulfide and alliin, organosulfur compounds present in garlic, significantly increased plasma noradrenaline and adrenaline concentrations, whereas the administration of disulfides without allyl residues, diallylmonosulfide and S-allyl-L-cysteine did not increase adrenaline secretion. These results suggest that in rats, allyl-containing sulfides in garlic enhance thermogenesis by increasing UCP content in IBAT, and noradrenaline and adrenaline secretion.

Adipose Tissue, Brown↗
PubMed1999

Oxygen uptake, heart rate, and blood lactate responses during and following karate training.

PURPOSE: The purpose of this study was to examine whether each exercise and an entire karate training session can achieve: 1) accepted training intensity thresholds for effective aerobic capacity training, 2) energy expenditure (EE) thresholds for total body mass and fat weight loss, and 3) elevation in excess postexercise oxygen consumption (EPOC). METHODS: We investigated physiological responses during five types of karate training: basic techniques without (S-Basics) and with (M-Basics) movements, sparring techniques without (TECH I) and with (TECH II) an opponent, and kata. RESULTS: The mean percent of maximal oxygen uptake (%VO2max) and HR (%HRmax) for S-Basics were below the accepted threshold (60% of HRmax or 50% of VO2max) and for M-Basics, TECH I and TECH II were above the threshold for increasing VO2max. For kata and the entire 70 min of karate training, the mean %HRmax were slightly above the threshold, and %VO2max were slightly below the threshold. The mean EPOC measured for 5 min immediately following 70 min of karate training did not differ from the resting VO2. The mean EE resulting from 70 min of karate exercise and EPOC were 2355.4+/-316.3 kJ and 38.8+/-32.7 kJ, respectively. CONCLUSIONS: Although the training intensity of karate exercises studied was moderate and the effects of karate training on EPOC were minimal, the mean value of EE was well above the accepted threshold for total body mass and fat weight loss.

Adult↗