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M Nagashima

Publications and source records attributed to M Nagashima.

At least 109 records · Page 6Linked to original sources
PubMed1998

Identification and characterization of two thrombin-activatable fibrinolysis inhibitor isoforms.

Thrombin-activatable fibrinolysis inhibitor (TAFI) is synthesized by the liver and is thought to circulate in plasma as a plasminogen-bound zymogen. When it is activated by the thrombin/thrombomodulin complex, activated TAFI exhibits carboxypeptidase B-like activity. To study the structure-function relationship of TAFI, we expressed recombinant human TAFI in insect cells. During the cloning of TAFI cDNA from several human liver cDNA libraries, we identified a second TAFI cDNA which differed from the published sequence at 2 positions. One of these sequences resulted in a substitution of alanine for threonine at residue 147, the other was a silent mutation. These substitutions were found in several cDNA libraries from different sources. Using Southern blot analysis, we confirmed the existence of this TAFI polymorphism in the population. In order to compare the activation and activity of TAFI isoforms, we expressed both isoforms in the baculovirus expression system, and compared the enzyme kinetics of the purified proteins. The molecular weight of recombinant TAFI is lower than plasma TAFI due to differences in glycosylation. The two recombinant TAFI isoforms had similar activation kinetics and the activated enzymes had similar carboxypeptidase B-like activity towards small molecule substrates. Their ability to retard clot lysis was found to be similar in a plate clot lysis assay.

Animals↗
PubMed1997

Mutation analysis of the transforming growth factor-beta type II receptor in human cell lines resistant to growth inhibition by transforming growth factor-beta.

The transforming growth factor-beta (TGF-beta) binds the type II TGF-beta growth factor receptor (RII) to inhibit the growth of most epithelial tissues. Most human colon and gastric cancers with microsatellite instability (MI) have frameshift mutations in polynucleotide repeats within the RII coding region; these mutations truncate the receptor protein and disable the serine/threonine kinase to produce TGF-beta resistance. To further investigate the type, frequency and tissue distribution of RII mutations, we selected 24 human cancer cell lines from various tissues which were previously reported to be resistant to the inhibitory effects of TGF-beta. We developed protocols for non-isotopic SSCP analysis of PCR products from genomic DNA samples, and we tested them for microsatellite instability. PCR-SSCP analysis followed by DNA sequencing identified deletion mutations in the exon 3 poly-adenine tract in three colon tumor cell lines: LS174T and SW48 had a single base deletion and LS411 had a two base deletion. Among the 24 previously unreported cell lines, only these three demonstrated microsatellite instability. These and other recent data indicate that RII mutations are essentially confined to colon and gastric cancers with microsatellite instability. The narrow spectrum of tissues containing RII mutations illustrates the complexity of genetic checkpoints in human carcinogenesis.

Cell Division↗
PubMed1997

FHIT mutations in human primary gastric cancer.

Allelic deletion of multiple regions on the short arm of chromosome 3 (3p) implies the presence of multiple important tumor suppressor genes in human carcinogenesis. The FHIT gene, identified recently in chromosome 3p14.2, shows frequent allelic deletion and aberrant transcripts in gastrointestinal tumors. After determining the intron sequences flanking each of the coding exons of the FHIT gene and designing intron primers to facilitate mutation analysis of genomic DNA samples, we analyzed the complete coding sequences in matched cancer and normal tissues from 40 cases with primary gastric cancer using intron primers, PCR-single-strand conformation polymorphism analysis, and direct sequencing. A somatic missense mutation in exon 6, codon 61, ACG (threonine) --> ATG (methionine) was found in a signet ring cell adenocarcinoma. We also evaluated allelic deletion in these tumors by PCR-based microsatellite analysis; allelic deletion occurred in 42.1% (16 of 38) of evaluable cases. This is the first report of a somatic missense mutation of the FHIT gene in a primary tumor. Presence of a point mutation and frequent allelic deletions are consistent with the hypothesis that FHIT gene alterations are involved in the development of primary gastric cancers.

Acid Anhydride Hydrolases↗
PubMed1997

Mutation analysis of coding sequences of the entire transforming growth factor beta type II receptor gene in sporadic human colon cancer using genomic DNA and intron primers.

Mutations in the transforming growth factor beta type II receptor (TGFbeta RII) gene have been detected in several human cancers exhibiting microsatellite instability. To extend analyses of this gene, we previously investigated the exon-intron organization of the TGFbeta RII gene and defined seven exons and flanking intron sequences. In this study, we further determined the nucleotide sequences surrounding these seven exons and designed eight sets of intron-based primers to examine the entire coding region of the TGFbeta RII gene. Using these primers, we screened genomic DNA sequences from 30 sporadic colorectal cancers for mutations of the TGFbeta RII gene. TGFbeta RII mutations were detected in two of 30 tumors and both displayed microsatellite instability. One had a deletion in a polyadenine tract in exon 3 and the other had a point mutation in the kinase domain located in exon 7. There were no mutations in exons 1, 2, 4, 5 and 6. These results further implicate the polyadenine tract and kinase domain as mutational hotspots in the TGFbeta RII gene in cells with genomic instability and suggest that TGFbeta RII gene mutations occur rarely in cells lacking genomic instability.

Base Sequence↗
PubMed1997

Presence of human cellular protein(s) that specifically binds and cleaves 8-hydroxyguanine containing DNA.

8-hydroxyguanine (oh8Gua) is a major form of oxygen free radical-induced DNA damage. The oh8Gua nucleotide can pair with cytosine (C) and adenine (A) nucleotides which can cause G:C to T:A transversions. It is known that multiple repair systems for the correction of the oh8Gua exist in both mammalian and bacterial cells. Using the technique of gel mobility shift assay, protein(s) bound to the oh8Gua:C base pair in short fragments of DNA was detected in cell-free extracts of a human small-cell lung cancer cell line. This DNA binding activity was specific, since it was poorly detected with an unmodified G:C base pair containing oligonucleotide duplex and was affected by neither the unmodified G:C base pair nor an oh8Gua:A base pair containing oligonucleotide duplex. The partially purified protein which selectively binds to the oh8Gua:C base pair was shown by gel filtration column chromatography to have an apparent molecular mass of 52 kDa. The column fraction which showed the highest binding activity to the oh8Gua:C base pair was found to possess an enzymatic activity that specifically cleaves the oh8Gua containing oligonucleotide strand at both the 5' and 3' sides of the oh8Gua residue. These results indicate the presence of a protein(s) that is involved in a DNA repair pathway for the correction of the oh8Gua residue in human cells.

DNA Repair↗
PubMed1997

Ventricular hypertrophy as a risk factor in ventricular septation for double-inlet left ventricle.

BACKGROUND: Ventricular septation is an option for surgical correlation of double-inlet or common-inlet left ventricle. However, the surgical risk factors of ventricular septation remain unknown. METHODS: Twenty-three patients with double-inlet or common-inlet left ventricle underwent ventricular septation. Preoperative data were compared between the survivors (n = 18) and the nonsurvivors (n = 5) to assess surgical risk factors. RESULTS: There were two early deaths (9.5%) and three late deaths (14.3%). Nonsurvivors of ventricular septation were significantly older at the time of operation (14.0 +/- 6.0 versus 7.0 +/- 5.4 years; p < 0.05) and had greater left ventricular mass (383% +/- 100% versus 206% +/- 57% of normal predicted value; p < 0.005) and greater left ventricular mass to left ventricular end-diastolic volume ratio (1.84% +/- 1.18% versus 0.77% +/- 0.17%/% of normal predicted value; p < 0.005). Univariate logistic regression analysis also revealed age at operation (p < 0.05) and mass/end-diastolic volume ratio (p < 0.05) as significant risk factors for death after operation. Multivariate regression analysis revealed that age at operation positively influenced increased mass/end-diastolic volume ratio (p < 0.001). These findings indicated that ventricular hypertrophy was one of the risk factors for ventricular septation, which had a tendency to progress with age. CONCLUSIONS: Early operation before progression of ventricular hypertrophy is recommended in patients with double-inlet or common-inlet left ventricle who have suitable anatomy for the ventricular septation procedure.

Adolescent↗
PubMed1997

Analysis of heart rate variability demonstrates effects of development on vagal modulation of heart rate in healthy children.

OBJECTIVES: Analysis of heart rate variability (HRV) has been found to be a useful method of assessing cardiovascular autonomic control, but normal values for standard HRV measures in children have not been established. We analyzed HRV in 60 healthy children aged 3 to 15 years to determine normal values and to assess the effects of development on cardiac autonomic control with the use of ambulatory electrocardiographic monitoring. RESULTS: The high-frequency (HF) component, an index of cardiac autonomic tone, increased significantly with age from 3 to 6 years (p < 0.01) and decreased with age from 6 to 15 years (p < 0.01), and the magnitude of HF correlated significantly with the R-R intervals. Thus the changes in cardiac autonomic tone could be described as a simple equation using age and heart rate. CONCLUSIONS: We present normal values and changes in the cardiac autonomic system during childhood after HRV analysis, which could lead to a better understanding and treatment of cardiac disease in children.

Adolescent↗
PubMed1997

Alpha 1-adrenoceptor subtype involved in the positive and negative inotropic responses to phenylephrine in rat papillary muscle.

1. In rat papillary muscle, stimulation of alpha 1-adrenoceptors results in a biphasic inotropic response: a transient negative inotropic phase and a subsequent sustained positive inotropic phase. This study was designed to determine whether the positive and negative inotropic effects in this tissue are mediated by different alpha 1-adrenoceptor subtypes. 2. After treatment with the tumor-promoting compound, phorbol 12, 13-dibutyrate, phenylephrine (in the presence of propranolol) produced only a positive inotropic effect. The selective alpha 1A-adrenoceptor antagonist, WB4101, significantly inhibited the positive inotropic effect. In contrast, inactivation of alpha 1B-adrenoceptors with chloroethylclonidine (CEC) did not alter the positive effect. 3. In the presence of the Ca2+ channel antagonist, nifedipine, phenylephrine induced only a sustained negative inotropic effect. The negative inotropic effect was significantly attenuated by WB4101, but was not affected by CEC. 4. We conclude that both the positive and negative inotropic responses of rat papillary muscle to phenylephrine are mediated exclusively by the WB4101-sensitive but CEC-resistant alpha 1-adrenoceptor subtype. The alpha 1-adrenoceptor subtype with such a property may correspond to the alpha 1A-subtype.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed1997

Lung carcinogenesis and formation of 8-hydroxy-deoxyguanosine in mice by diesel exhaust particles.

In order to clarify the involvement of oxygen radicals in lung carcinogenesis induced by diesel exhaust particles (DEP), the relationship between lung tumour response and formation of 8-hydroxydeoxyguanosine (8-OHdG) in lung DNA was examined. The role of high dietary fat and beta-carotene on these responses was also studied. Mice were intratracheally injected with 0.05, 0.1 and 0.2 mg of DEP per animal once weekly for 10 weeks. After 12 months, the lung tumour incidence in mice treated with 0.05 mg and 0.1 mg showed similar increases (30% and 31%), but was decreased to 24% at 0.2 mg. High dietary fat enhanced the incidence of both benign and malignant tumours. beta-carotene partially prevented the tumour development. After the 10 weekly treatments of DEP, inflammatory reaction was observed in the respiratory tract and alveoli. The formation of 8-OHdG in lung DNA from mice treated with DEP showed a dose dependent increase. 8-OHdG formation was enhanced by high dietary fat and partially reduced by beta-carotene. Formation of 8-OHdG was significantly correlated with the lung tumour incidence except at 0.2 mg. These results suggest that the induction of oxidative DNA damage may be an important factor in the initiation of DEP-induced lung carcinogenesis, and that beta-carotene and high dietary fat may play a role in the regulation of tumour development via modulation of the formation of 8-OHdG.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1997

Absence of mutations in the transforming growth factor-beta type II receptor in sporadic lung cancers with microsatellite instability and rare H-ras1 alleles.

The transforming growth factor-beta type II receptor (RII) is commonly mutated in colon and gastric cancers with microsatellite instability (MI). We utilized our series of lung cancers with MI and rare alleles of the H-ras1 gene to determine the association between MI and RII mutations and searched the entire RII coding region in 33 lung cancers with MI by polymerase chain reaction-single-strand conformation polymorphism analysis. We found no mutations, and these data support other recent evidence that RII mutations rarely occur except in colon and gastric tumors with MI.

Alleles↗
PubMed1997

Recombinant advanced glycation end product receptor pharmacokinetics in normal and diabetic rats.

Vascular dysfunction in patients with diabetes mellitus is related to advanced glycation end product (AGE) formation. We previously showed that AGEs produce an increase in vascular permeability and generated an oxidant stress after binding to the receptor (RAGE) present on endothelium. RAGE, a 35-kDa protein that belongs to the immunoglobulin superfamily, has been cloned from a rat lung cDNA library, and recombinant rat soluble RAGE (rR-RAGE) has been produced in insect cells. The sequence of RAGE is highly conserved between human and rat. We studied the biological effect of rR-RAGE and pharmacokinetics of 125I-rR-RAGE after intravenous or intraperitoneal administration in normal and streptozotocin-induced diabetic rats. rR-RAGE prevented albumin or inulin transfer through a bovine aortic endothelial cell monolayer, restored the hyperpermeability observed in diabetic rats or induced in normal rats by diabetic rat red blood cells, and corrected the reactive oxygen intermediate production after intravenous or intraperitoneal administration. After intravenous injection of 125I-rR-RAGE, the distribution half-life was longer (p < or = 0.01) in diabetic (0.15 and 4.01 hr) than in normal (0.02 and 0.21 hr) rats, as was the case for the elimination half-lives (diabetic, 57.17 hr; normal, 26.02 hr; p < or = 0.01). Distribution volume was higher in diabetic than in normal rats (6.94 and 3.24 liter/kg, respectively; p = 0.049). Our study showed that rR-RAGE was biologically active in vivo and slowly cleared, which suggests it could be considered as a potential therapy.

Amino Acid Sequence↗
PubMed1997

Random amplified polymorphic DNA (RAPD) analyses for discriminating genotypes of Microcystis cyanobacteria.

Random amplified polymorphic DNA (RAPD) analysis was used to discriminate genotypes in five species of Microcystis cyanobacteria. Strains of each group with the identical allozyme genotype (T. Kato et al., Algol. Stud., 1991, 129-140; M. Watanabe, in "Toxic Microcystis," ed. by M.F. Watanabe et al., CRC Press, Tokyo, 1966, pp. 13-34) gave similar RAPD patterns characterizing the respective group. On the other hand, no similarities in RAPD patterns were observed among strains of which allozyme genotypes were different. A good accordance between the RAPD analysis and allozyme divergence indicated a high reliability of both methods for discrimination of the affiliated groups of Microcystis. Several amplified DNA fragments, which were expected to be markers for a particular taxon with identical allozyme genotype, were also observed on the RAPD patterns. Genetic homogeneities of M. novacekii, M. viridis, and M. wesenbergii were shown by RAPD analysis as well as the allozyme genotype. However, significant variations were observed in M. aeruginosa and M. ichthyoblabe in the levels of DNA and proteins (allozymes).

DNA Primers↗
PubMed1997

[Reproducibility of spasm in patients with long-term remission of vasospastic angina by medical treatment].

The reproducibility of coronary vasospasm was assessed in nine patients with complete remission of vasospastic angina by medical treatment by reexamination at intervals of mean [+/-SD] 5.7 +/- 0.9 years. Twenty-one segments were defined as spastic, demonstrating more than 90% narrowing after acetylcholine injection at the initial angiography. The degree of spasticity, type of spasm (diffuse or focal) and coronary artery diameter in these segments at the initial and follow-up studies were compared. Of the 21 segments, 17 (81%) still had some spasticity (> 25%) at the follow-up study and 8 (38%) of these 17 showed spasticity with greater than 90% narrowing. On the other hand, spasm was not reprovoked in 4 (19%) segments. Luminal diameter of the spastic segments decreased significantly at the follow-up study (2.52 +/- 0.83 vs 2.26 +/- 0.62 mm, p = 0.01), but percentage stenosis was not different between the initial and follow-up studies (9.1 +/- 7.2 vs 10.3 +/- 8.0%, NS). The reproducibility of the type of spasm provoked was 83%. Coronary vasospasticity persists to some extent in spite of complete remission of angina by medical treatment, and the type of spasm provoked has high reproducibility. Therefore, the cessation of drug treatment should be done carefully.

Acetylcholine↗
PubMed1997

Thrombin, thrombomodulin and TAFI in the molecular link between coagulation and fibrinolysis.

The thrombin thrombomodulin dependent activation of the plasma protein TAFI (Thrombin Activatable Fibrinolysis Inhibitor) and Subsequent Inhibition of Fibrinolysis by the TAFIa is described. Work to date indicates that TAFIa is a carboxypeptidase B enzyme that suppress fibrinolysis most likely by down regulating the cofactor functions of partially degraded fibrin. The existence of TAFI provides the explanation for the apparent profibrinolytic effect of activated protein C. and implies the existence of an explicit molecular connection between the blood coagulation of fibrinolytic cascades that is expressed through the thrombin thrombomodulin dependent activation of TAFI. Thus, thrombin generation can, in principle, result in the suppression of fibrinolysis.

Amino Acid Sequence↗
PubMed1997

Vascular reactivity to endothelium-derived relaxing factor in human umbilical artery at term pregnancy.

It has been reported that human umbilical artery (HUA) at term pregnancy released endothelium-derived relaxing factor (EDRF), using a superfusion bioassay system. However, other reports showed that endothelium-dependent relaxation was not observed in isometric tension studies using HUA ring with intact endothelium. Thus, we intended to clarify whether vascular smooth muscle of HUA at term is sensitive to EDRF. HUA was obtained after normal vaginal delivery or cesarean section at term. Isometric tension studies were performed in normal Krebs solution, using HUA rings or strips, which were prepared in calcium-free Krebs solution. Sodium nitroprusside (SNP), a nitric oxide (NO) donor drug, relaxed HUA rings precontracted with 0.1 microM 5-hydroxytryptamine (5HT) in a dose-dependent manner (1 nM-10 microM). Histamine, substance P, carbachol, or the calcium ionophore A23187, which are considered to be EDRF-releasing agents, did not relax the HUA rings. By immunohistochemical study, it was confirmed that endothelial cells were present in the luminal surface of the HUA rings after the isometric tension recording. In a co-axial bioassay system involving HUA strips denuded of endothelium and rabbit aorta with intact endothelium, HUA strips precontracted with 0.1 microM 5HT were relaxed in response to 1 microM SNP but not 1 microM carbachol, which released EDRF from the endothelium of rabbit aorta. These findings suggest that HUA at term is sensitive to NO but not EDRF.

Animals↗
PubMed1997

Cardiorespiratory response to exercise in patients with exercise-induced bronchial obstruction.

OBJECTIVE: To document the characteristics of the ventilatory response to exercise in patients with exercise-induced bronchial obstruction (EIB). EXPERIMENTAL DESIGN: Comparative study during the period between December 1993 and March 1994. SETTING: Ambulatory care in Ohgaki Municipal Hospital. SUBJECTS AND METHOD: We evaluated 11 children with EIB. Each subject under went symptom-limited cardiopulmonary treadmill exercise testing (Bruce protocol). RESULTS: Patients with EIB showed a significantly lower peak oxygen consumption (peak VO2) than the control subjects. Three patients with EIB developed relative hypoventilation during incremental exercise: an increase in end-tidal carbon dioxide partial pressure (PETCO2) and a decrease in VE/VCO2 were observed at the end-stage of exercise testing. CONCLUSIONS: These findings demonstrate that some patients with EIB develop bronchoconstriction during exercise.

Adolescent↗
PubMed1997

[Studies on the foramen vesalius in the Japanese juvenile and adult skulls].

Foramen Vesalius is known to be an inconstant foramen, which appears in the anteriomedial side of the foramen ovale. The foramen Vesalius is classified into the open type and the closed type. We studied the frequencies and the types of foramen Vesalius in Japanese by examining 20 juvenile skulls from 3 months to 8 years old and 400 adult skulls from 18 to 91 years old. Of the 20 juvenile skulls, 11 skulls (55.00%) had foramen Vesalius. Of the 400 adult skulls, 87 skulls (21.75%) had foramen Vesalius; 69 (21.50%) in 321 male and 18 (22.78%) in 79 female skulls. No remarkable differences were observed in the ratio between the male and the female, and between the left side and the right side. Among the 69 adult male skulls, the foramen Vesalius was bilateral in 52 skulls (75.36%) and unilateral in 17 (24.64%); among the 18 adult female skulls, it was bilateral in 13 (72.22%) and unilateral in 5 (27.78%). The ratio of the closed type was slightly higher than that of the open type in both sexes and in both sides; however, no remarkable differences were observed. The skulls with one foramen Vesalius were most frequent; those with two followed it and those with 3 foramen Vesalius were least frequent. No remarkable differences were observed in the number of foramen Vesalius between the sexes and the sides.

Adolescent↗