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S Nishimura

Publications and source records attributed to S Nishimura.

At least 163 records · Page 9Linked to original sources
PubMed1999

In vivo anti-tumor activity of a novel indolocarbazole compound, J-107088, on murine and human tumors transplanted into mice.

J-107088 (6-N-(1-hydroxymethyl-2-hydroxy)ethylamino-12,13-dihydro-2,10-dihydroxy- 13-(beta-D-glucopyranosyl)-5H-indolo[2,3-a]-pyrrolo [3,4-c]carbazole-5,7(6H)-dione) is a derivative of NB-506, an indolocarbazole compound previously reported as an anti-tumor agent targeting topoisomerase I. The optimal administration schedule of J-107088 was found to be intermittent injections. The GID75 (75% growth inhibiting total dose) values of J-107088 against LX-1 lung cancer and PC-3 prostate cancer when given by intermittent injection (twice a week for 2 consecutive weeks) were 200 and 15 mg/m2, respectively, whereas the 10% lethal dose (LD10) values of J-107088 against LX-1- and PC-3-bearing mice were 578 and 1200 mg/m2. The ratio of LD10/GID75 indicates the therapeutic window of an anti-tumor agent. Although the ratios of doxorubicin, paclitaxel and cisplatin against PC-3 were <0.3, <0.5 and <0.2, J-107088 showed the widest therapeutic window among the anti-tumor drugs tested. J-107088 was also effective on cells that had acquired resistance related to P-glycoprotein. Furthermore, J-107088 was found to be highly effective in inhibiting proliferation of micro-metastases of tumors to the liver in mice. Therefore, J-107088 is considered to be a promising candidate as an anti-tumor drug for treatment of solid tumors in humans.

Animals↗
PubMed1999

Metabolic and morphologic characteristics of adipose tissue associated with the growth of malignant tumors.

Changes in total body fat and the metabolic and morphologic characteristics of adipose tissue were sequentially investigated in individual rabbits implanted with VX2 tumors to elucidate the pathology of the fat reduction in animals with malignant tumors as compared with that of diet-restricted rabbits. Lipogenesis in normal, VX2-implanted, and diet-restricted rabbit groups on day 40 after the start of the experiments was 19.1 +/- 2.9, 13.3 +/- 3.5, and 41.7 +/- 6.0 x 10(5) cpm/g/h, respectively, and glycerol liberation by their adipose tissue was 199 +/- 21, 528 +/- 94, and 301 +/- 45 nmol/g/h, respectively. In addition, apoptotic cells were noted in the adipose tissue of VX2-implanted rabbits on days 20-30 after implantation, but not in diet-restricted rabbits. The results showed clear differences between the total body fat reduction profiles of VX2-implanted rabbits and diet-restricted rabbits, suggesting a characteristic lipid metabolism with enhanced lipolysis and diminished lipogenesis in VX2-implanted rabbits. The results strongly suggest that adipocyte apoptosis might be involved in these phenomena.

Adipose Tissue↗
PubMed1999

Azatyrosine. Mechanism of action for conversion of transformed phenotype to normal.

Azatyrosine [L-beta-(5-hydroxy-2-pyridyl)-alanine] has the unique property of converting ras- or c-erbB-2 transformed phenotype to normal. The administration of azatyrosine also inhibits tumor formation in transgenic mice harboring the normal human c-Ha-ras which is mutated during treatment with various chemical carcinogens. To elucidate the molecular mechanism, we investigated how azatyrosine functions and what are its major targets. Azatyrosine functions downstream of ras; azatyrosine does not alter either the level of GTP-bound Ras or the total amount of Ras. Instead, azatyrosine inhibits the activation of c-Raf-1 kinase by oncogenic c-ErbB-2, resulting in inactivation of AP1. It is interesting that azatyrosine also restores the expression of the rhoB gene, the product of which regulates the formation of actin stress fibers. Azatyrosine is incorporated into cellular proteins to replace tyrosine. Several experiments indicate that replacement of tyrosine is likely to be a cause for its conversion of transformed phenotype to normal. To prove this hypothesis, we are attempting to develop a mutant of tyrosyl-tRNA synthetase that, unlike wild type, can aminoacylate azatyrosine more efficiently than can tyrosine.

Alanine↗
PubMed1999

Serotypes of human rotaviruses in 7 regions of Japan from 1984 to 1997.

Human rotavirus (HRV) serotypes were studied from diarrheal stool specimens in children in 7 regions of Japan (Sapporo, Tokyo, Maizuru, Osaka, Kagawa, Kurume, and Saga) from 1984 to 1997 by enzyme immunoassay (EIA) with serotype-specific monoclonal antibodies against serotypes 1, 2, 3, and 4. In addition, reverse transcription-polymerase chain reaction (RT-PCR) was conducted for analysis of "others" which included nonserotypable and mixed-serotype rotavirus specimens by EIA. In 3756 rotavirus-positive specimens, serotype 1 was detected in 2649 (70.5%), serotype 2 in 362 (9.6%), serotype 3 in 232 (6.2%) and serotype 4 in 196 (5.2%). Overall, serotype 1 was predominant from 1984 to 1997, although there were a few cases in which serotype 2, 3 and 4 became predominant based on area and year. The frequency of serotype 1 has gradually increased since 1993. Twenty two, 2, 3 and 1 among 57 specimens of "others" by EIA from Tokyo, Maizuru, Sapporo and Kurume in 1995-1996 and 1996-1997 were determined as serotypes 1, 2, 3, and 9 by RT-PCR, respectively.

Child↗
PubMed1999

Structure and chromosome location of human OGG1.

OGG1 (alias MMH) encodes an 8-hydroxyguanine glycosylase, functionally homologous to bacterial mutM. Here, we report its genomic structure and fine chromosome location. The human OGG1 gene corresponding to the isoform 1 transcripts, consists of seven exons, spanning 7,421 bps, while an alternative additional exon, utilized for isoform 2, is located approximately 9 kb downstream. TATA-like sequence was not found in the 5'-upstream region, common in so-called "housekeeping" genes. The last 55 bases of the 3' untranslated region in exon 7 were unexpectedly conserved among species, presumably because the 3' end of the CAMK1 gene, which is transcribed convergently on the opposite strand, is overlapped at the 3' end. By radiation hybrid panel mapping, OGG1 was localized between WI-4179 and AFMA216ZG1 at 3p26, proximal to the VHL gene.

3' Untranslated Regions↗
PubMed1999

Lipolytic activity of anemia-inducing substance from tumor-bearing rabbits.

Anemia-inducing substance (AIS) is a protein of approximately 50,000 molecular weight secreted by malignant tumor tissue that depresses erythrocyte and immuno-competent cell functions; in this study, its biological effects on adipocytes were examined. Changes in body weight, total body fat, and food intake were investigated in rabbits after VX2 carcinoma transplantation, and the results showed reductions of 11%, 24%, and 30%, respectively, at 40 days after transplantation compared with baseline values (before transplantation). The values were even more markedly reduced 70 days after transplantation. When cyclic plasma perfusion (2 times/wk) was started at 40 days after transplantation, the values at 70 days after transplantation (30 days after beginning plasma perfusion) recovered to 91%, 84%, and 87%, respectively, of the baseline values. AIS fractions were isolated from rabbit plasma by using a phenyl-Sepharose column before transplantation, 40 and 70 days after transplantation, and 30 days after start of plasma perfusion, and AIS activity and lipolytic activity were measured. The results showed enhancement of AIS activity and lipolytic activity as the tumors grew. Lipolytic activity also returned to baseline value as AIS was removed by adsorption by plasma perfusion, and there was a high correlation between lipolytic activity and AIS kinetics. These results strongly suggest that AIS might be one of the substances involved in the enhanced lipolytic activity in advanced tumor-bearing subjects.

Adipose Tissue↗
PubMed1999

Distinct roles for astrocyte alphavbeta5 and alphavbeta8 integrins in adhesion and migration.

The alphav integrins are likely to be an important group of molecules for regulating astrocyte behaviour within the central nervous system. Together with their ligand vitronectin, they are expressed by astrocytes in vivo and are further upregulated during neurological disease. Here we have characterised the expression of alphav integrins on primary astrocytes from both rat and mouse, and shown that they express just two members, alphavbeta5 and alphavbeta8. By using RGD peptides and function-blocking antibodies against the beta1 integrins and alphavbeta5, we find that both alphavbeta5 and alphavbeta8 can act as functional receptors for vitronectin. However, while alphavbeta5 is largely responsible for astrocyte adhesion to vitronectin this integrin appears to play no role in migration on vitronectin, with alphavbeta8 playing the dominant role in promoting migration on this substrate. beta1 integrins are not involved in mediating interactions between astrocytes and vitronectin. These results were confirmed in experiments with astrocytes derived from mice in which the beta5 gene had been deleted by homologous recombination. beta5 null astrocytes attached to vitronectin at a reduced rate, but showed no defect in migration on vitronectin relative to wild-type astrocytes. These data provide the first evidence that alphavbeta8 regulates migration and show that astrocyte alphavbeta5 and alphavbeta8 integrins have distinct functions.

Animals↗
PubMed1999

Sequestration of depolarization-induced Ca2+ loads by mitochondria and Ca2+ efflux via mitochondrial Na+/Ca2+ exchanger in bovine adrenal chromaffin cells.

We used fura-2 microfluorometry to investigate the role of mitochondria in regulating the increase in the cytosolic Ca2+ concentration ([Ca]in) and the mechanism(s) underlying the subsequent Ca2+ efflux from mitochondria in bovine adrenal chromaffin cells. The rate of [Ca]in decay during and following stimulation with 100 mM KCl depolarization was markedly increased when the mitochondrial Na+/Ca2+ exchanger was inhibited by clonazepam or CGP-37157(CGP). In contrast, the addition of gramicidin, which increased the cytosolic Na+ concentration, following KCl depolarization caused a secondary increase in [Ca]in. This secondary increase in [Ca]in was prevented by the addition of clonazepam or CGP, and by the removal of external Na+. The subsequent removal of clonazepam or CGP, or the delayed addition of Na+ caused a slow increase in [Ca]in. A protonophore (FCCP) applied following KCl depolarization also caused a robust, secondary increase in [Ca]in, which was insensitive to blocking by clonazepam or CGP. Neither gramicidin nor FCCP altered the [Ca]in decay when applied following stimulation with histamine or caffeine, which mobilized Ca2+ from intracellular stores. These results suggest that the large [Ca]in increase induced by Ca2+ influx, but not by intracellular Ca2+ release, is buffered by mitochondria, and that the mitochondrial Na+/Ca2+ exchanger makes a major contribution to the subsequent Ca2+ efflux from mitochondria.

Adrenal Glands↗
PubMed1999

Matrix metalloproteinase-1 expression is a prognostic factor for patients with advanced gastric cancer.

Proteolytic activity of cancer cells is an important factor in metastasis. This study examined the relationship between MMP-1 expression of gastric cancer cells and peritoneal metastasis. MMP-1 expression was found in 76/103 (75.2%) cases examined and was significantly associated with both peritoneal metastasis and lymph node metastasis (p<0.05, respectively). The prognosis of patients with MMP-1 positive tumor was significantly worse than that of patients with MMP-1 negative tumor (p<0.05). These findings suggested that MMP-1 might be a prognostic factor in case of advanced gastric cancer and might be useful in determining whether or not adjuvant therapy was indicated for patients at high risk of peritoneal recurrence.

Adult↗
PubMed1999

Treatment of infant acute lymphoblastic leukemia in Japan. Childhood Leukemia Study Group of the Ministry of Health and Welfare (Kouseisho).

Although current chemotherapeutic regimens cure as many as 70% of children with acute lymphoblastic leukemia (ALL), infants continue to show a poor outcome. In this paper, we describe the outcome in 37 ALL infants treated between 1989 and 1995 in Japan. Patients had characteristic findings of infant ALL, including hyperleukocytosis > 100 x 10(9)/l (15/37, 41%), blast cells with a CD10-negative phenotype (30/37, 81%), and 11q23/MLL involvement (21/37, 57%). Seven were treated according to Aggressive Treatment Research Group protocol, 15 according to the Ministry of Health and Welfare protocol, and 15 according to protocols of other institutions. The 3-year overall event-free survival (EFS) was 33%. The EFS was 13% for infants aged < 26 weeks at diagnosis and 43% for infants aged > 26 weeks. Infants who had blast cells with CD10 negative phenotype with 11q23/MLL involvement were also associated with poor prognosis. However, infants with CD10 positive blasts without 11q23/MLL involvement had a better outcome (EFS 75%). These results suggest that intensive chemotherapy is effective for patients with good prognostic factors, but for infants with poor prognostic factors a more aggressive approach such as stem cell transplantation might be necessary.

Female↗
PubMed1999

Elimination of anemia-inducing substance by cyclic plasma perfusion of tumor-bearing rabbits.

We carried out a fundamental study to search for a therapeutic modality that would remove the anemia-inducing substance (AIS) from the plasma of cancer patients because it is thought to be one of the substances responsible for anemia and immunodeficiency in advanced cancer patients. Using AIS isolated from the plasma of patients with advanced ovarian carcinoma, we confirmed that adsorption of AIS to noncoated charcoal was nonspecific and high. Moreover, it was verified that VX2 carcinoma-bearing rabbits are an optimal experimental model for plasma perfusion. The data obtained on day 40 after transplantation (hemoglobin, 9.1+/-2.1 g/dl; osmotic pressure inducing RBC lysis, 137+/-11 mosmol/kg; lymphocyte stimulation index, 8.8+/-8.6; and RBC fragility-inducing activity, 40+/-9 mosmol/kg) proved similar to the hematological findings in patients with cancer cachexia. A 1-h plasma perfusion (3 ml/min) through noncoated charcoal was performed in tumor-bearing rabbits, and it resulted in the restoration of RBC fragility-inducing activity and suppression of lymphocyte blast formation to pretransplantation values. When plasma perfusion was performed every 3 days, RBC fragility-inducing activity, which increased again 3 days after perfusion, was diminished, and RBC osmotic resistance was within the normal range from the fourth perfusion onward. These results showed that cyclic plasma perfusion is effective in sustained removal of RBC fragility-inducing factor from plasma, suggesting that it might have the potential for clinical application.

Adsorption↗
PubMed1999

[Evaluation of mortality of patients admitted to ICU for the last 12 years].

We evaluated mortality of 2689 patients admitted to the Intensive Care Unit, Osaka University Hospital from January, 1987 to December, 1998. The patients were divided into 3 groups. Group A consisted of 1408 patients who underwent cardiovascular surgery, group B, 1082 patients who underwent other surgical procedures and group C, 199 patients who were transferred from the department of medicine. We studied mortality rate, causes of death, correlation between length of ICU stay and mortality rate, and mortality rate among age groups for 12 years. The main causes of death were cardiac failure and sepsis in group A, and respiratory failure and sepsis in group B and C. Mortality rate in each group showed no significant change for the last 12 years. Those who stayed more than 2 weeks in ICU showed a significantly higher mortality rate (p < 0.0001). Thus, length of ICU stay and mortality rate showed a positive correlation (p < 0.0001). The youngest group (age 0-1) showed a significantly higher mortality rate than other age groups (p < 0.0001). As sepsis was the most important cause of death in all the groups, the prevention and treatment of infection are the most important issue in our ICU to reduce mortality rate.

Adolescent↗
PubMed1999

A comparative study on the hypouricemic activity and potency in renal xanthine calculus formation of two xanthine oxidase/xanthine dehydrogenase inhibitors: TEI-6720 and allopurinol in rats.

In this study, the hypouricemic efficacy of a novel xanthine oxidase/xanthine dehydrogenase inhibitor, TEI-6720, was compared with that of allopurinol in a hyperuricemic rat model established by feeding the animals oxonate, a uricase inhibitor. In addition, using normal rats, the changes in xanthine concentration in plasma and the concentrations and absolute quantities of uric acid, allantoin and xanthine in urine were analyzed during a 28-day period of repeated administration of TEI-6720 to determine the changes occurring during this period and the conditions required for the formation of xanthine crystals and calculi in comparison with allopurinol. TEI-6720 and allopurinol caused a significant dose-dependent decrease in plasma uric acid levels in the hyperuricemic rat model and the ED50 of TEI-6720 was lower than that of allopurinol, indicating that in terms of hypouricemic efficacy TEI-6720 is more potent than allopurinol. TEI-6720 also showed more potent activity than allopurinol in decreasing urinary uric acid and allantoin levels in normal rats. In addition, TEI-6720 and allopurinol showed similar dose-response curves for the decrease in uric acid or allantoin concentration, and the associated increase in xanthine concentration, indicating that TEI-6720 and allopurinol have similar pharmacological characteristics although the dosage required differs. The efficacy of TEI-6720 in increasing plasma and urinary xanthine levels in normal rats was approximately 10- to 30-fold greater than that of allopurinol. However, with respect to renal xanthine calculus formation, there was only about a 3-fold difference in dosage comparing TEI-6720 and allopurinol. This difference suggests that there may be another factor independent of xanthine, and dependent on the drug itself, involved in renal calculus formation caused by allopurinol. The daily excretion of purine metabolites per body weight was about 20-fold higher in rats than in humans. From these results, it is concluded that TEI-6720 has potent hypouricemic activity and that, compared to allopurinol, administration of TEI-6720 is not likely to result in a higher incidence of calculus formation.

Allantoin↗
PubMed1999

A DNA binding indolocarbazole disaccharide derivative remains highly cytotoxic without inhibiting topoisomerase I.

NB-506 is a glucosylated indolocarbazole related to the antibiotic rebeccamycin and is currently under clinical trials as an anticancer drug. This compound is a DNA intercalating agent and a potent topoisomerase I poison. The glucose residue attached to the planar indolocarbazole chromophore plays a significant role in the interaction of the drug with nucleic acids and contributes positively to the stabilization of topoisomerase I-DNA covalent complexes. To investigate further the influence of the carbohydrate moiety, we studied the DNA binding and topoisomerase I inhibition properties of an analogue of NB-506 bearing a disaccharide side chain. Fluorescence and footprinting studies indicate that the replacement of the glucose chain of NB-506 with a maltose residue does not hinder the capacity of the drug to bind to DNA and to recognize GC-rich sequences. The addition of the second sugar residue does not reinforce the interaction with DNA but abolishes the capacity of the drug to inhibit topoisomerase I. Unexpectedly, the disaccharide analogue of NB-506 has totally lost its capacity to stimulate DNA cleavage by topoisomerase I. In addition, like NB-506, the new analogue is not an inhibitor of topoisomerase II. However, despite the absence of topoisomerase poisoning activity, the cytotoxic activity is fully maintained. The maltosyl-indolocarbazole drug proved to be as potent as NB-506 at inhibiting the growth of various human and murine tumour cell lines. The study raises the question as to whether topoisomerase I poisoning is important for the antitumour activity of rebeccamycin analogues.

Animals↗
PubMed1998

Binding of volatile anesthetics to purple membranes studied by X-ray diffraction.

Volatile anesthetics, diiodomethane and trifluoroethyl iodide, acted on the purple membrane of Halobacterium halobium in two different modes depending on the concentration. At low concentration, the absorption maximum of bacteriorhodopsin shifted from 561 to 558 nm (BR558) and the M-intermediate of the photocycle decayed faster than the native one. Higher concentration induced a species absorbing maximally at 480 nm (BR480) and the long-lived M-intermediates. The X-ray study suggested that anesthetics bound specifically to the protein-lipid interfacial region within a trimer near the surface of membrane in BR558 and entered into the hydrophobic domain of the membrane in BR480.

Anesthetics, Inhalation↗
PubMed1998

Determination of acrolein in human urine by headspace gas chromatography and mass spectrometry.

A rapid and sensitive headspace gas chromatographic and mass spectrometric (GC-MS) method was developed for the determination of acrolein in human urine. A 0.5-ml urine sample in a glass vial containing propionaldehyde as an internal standard was heated at 80 degrees C for 5 min. A 0.1-ml volume of headspace vapor was injected into a GC-MS instrument. Acrolein and propionaldehyde were coeluted at 3.1 min using a DB-1 capillary column, and well separated by selective ion monitoring (SIM) mode using ions m/z 56.05 and m/z 58.05. The interassay and intraassay coefficient of variation were 0.99% and 3.3%. The calibration curve demonstrated a good linearity throughout concentrations ranging from 1 to 1000 nM. However, due to a wide variation of acrolein evaporation rates from human urine, a calibration curve must be established for each urine specimen using a standard addition method and detection limit varied from 1 to 5 nM. The total analysis time for two samples from one urine specimen required about 15 min. Therefore, this method is convenient for the urgent monitoring of urinary acrolein in patients to whom alkylating agents are administered.

Acrolein↗