Biomedical subjects

M Iwanaga

Publications and source records attributed to M Iwanaga.

At least 55 records · Page 3Linked to original sources

PubMed1998

Bombyx mori nucleopolyhedrovirus encodes a DNA-binding protein capable of destabilizing duplex DNA.

A DNA-binding protein (designated DBP) with an apparent molecular mass of 38 kDa was purified to homogeneity from BmN cells (derived from Bombyx mori) infected with the B. mori nucleopolyhedrovirus (BmNPV). Six peptides obtained after digestion of the isolated protein with Achromobacter protease I were partially or completely sequenced. The determined amino acid sequences indicated that DBP was encoded by an open reading frame (ORF16) located at nucleotides (nt) 16189 to 17139 in the BmNPV genome (GenBank accession no. L33180). This ORF (designated dbp) is a homolog of Autographa californica multicapsid NPV ORF25, whose product has not been identified. BmNPV DBP is predicted to contain 317 amino acids (calculated molecular mass of 36.7 kDa) and to have an isoelectric point of 7.8. DBP showed a tendency to multimerization in the course of purification and was found to bind preferentially to single-stranded DNA. When bound to oligonucleotides, DBP protected them from hydrolysis by phage T4 DNA polymerase-associated 3'-->5' exonuclease. The sizes of the protected fragments indicated that a binding site size for DBP is about 30 nt per protein monomer. DBP, but not BmNPV LEF-3, was capable of unwinding partial DNA duplexes in an in vitro system. This helix-destabilizing ability is consistent with the prediction that DBP functions as a single-stranded DNA binding protein in virus replication.

Amino Acid Sequence↗

PubMed1998

Preference for musical tempo involving systematic variations of presented tempi for known and unknown musical excerpts.

Previous studies have indicated inconsistently that preferred tempo was moderate or fast. The basis for inconsistency might be differences in methods, i.e., differences in tempo operation and subjects' experience of listening to musical pieces. The present study examined the preference for tempo using known and unknown melodies which were presented at varied tempi systematically. 119 undergraduates not majoring in music were subjects, divided into three subgroups, slow, medium, and fast music groups according to tempi designated by composers. Subjects rated items about Perceived Activity and affect for each stimulus presented at varied tempi. Subjects evaluated fast tempi as active regardless of differences in the designated tempi and prior listening experience. Affect (including preference) showed an inverted-U shape relationship to variations in tempo. The most preferred tempo was the designated tempo for known melodies, while moderate tempi (109 to 130 in metronome measure) were preferred for unknown melodies.

Acoustic Stimulation↗

PubMed1997

Molecular analysis of a filamentous phage (fsl) of Vibrio cholerae O139.

A filamentous bacteriophage from Vibrio cholerae O139 strain A1-4450 was isolated (fsl). The phage fsl had a ssDNA genome and dsDNA as a replicative form (RF) in lysogenic host cell. The DNA sequence of fsl RF was determined. It consisted of 6340 bp and had a G + C content of 43.5%. Fifteen possible ORFs were found in fsl. One of them, ORF384, was estimated to encode 384 amino acid residues (44.6 kDa) and had homologous regions with the zot gene of V. cholerae and gene I of the coliphage group. ORF104, located upstream of ORF384, was homologous to gene 93 protein of Pf3 (filamentous phage of Pseudomonas sp.) corresponding to gene VI of coliphage. Other than ORF384 and ORF104, the ORF81, ORF44, ORF29, and ORF193 were speculated to correspond to gene V, gene VII, gene IX, and gene III, respectively, in the order as reported on f1 phage.

Amino Acid Sequence↗

PubMed1997

Cyclin-D1-gene amplification is a more potent prognostic factor than its protein over-expression in human head-and-neck squamous-cell carcinoma.

To evaluate the prognostic significance of cyclin D1 protein/gene expressions in human head-and-neck squamous-cell carcinoma (HNSCC), we examined amplification of the cyclin-D1 gene (CCND1) by the differential PCR method and over-expression of cyclin-D1 protein by immunohistochemistry in 45 paraffin-embedded sections from HNSCC. Amplification of CCND1 was found in 10 (22%) cases and over-expression of cyclin D1 was found in 24 (53%) cases. CCND1 amplification was also found in 3 (25%) of 12 cases of dysplastic lesions adjacent to HNSCC. The overall 5-year survival of patients with CCND1 amplification or with protein over-production was significantly lower than that of patients without (p < 0.0001 and p < 0.05, respectively). However, with multivariate analysis, only amplification of CCND1 retained an independent prognostic value (p = 0.0018). These suggest that CCND1 amplification occurs at early stages of HNSCC tumorigenesis and is a more useful prognostic factor than over-expression of cyclin D1 in HNSCC.

Adult↗

PubMed1997

Characterization of filamentous phages of Vibrio cholerae O139 and O1.

We have analyzed our collection of Vibrio cholerae O139 strains to determine whether filamentous phages are produced in their culture supernatants, and whether any replicative form of DNA is detectable in cell lysates. Two types of filamentous phage, designated fs1 (6.4 kb) and fs2 (8.5 kb), were found in strains of Vibrio cholerae O139, fs1 was commonly produced from clinical isolates of Vibrio cholerae O1. Infectious particles (filamentous phages) were inducible by subculture, mitomycin C, and cultivation in a ligated ileal loop of a rabbit. Type 4 fimbriae of Vibrio cholerae O1 sensitive to D-glucose and D-mannose were suggested to be receptors for fs1 and fs2. The genome of fs1 was revealed to encode a potential new enterotoxin homologous to zonula occludens toxin. Clarification of the relation of type 4 fimbriae and these filamentous phages will provide a new understanding of the colonization of Vibrio-cholerae O1 and O139. Thus the presence of a new enterotoxin encoded by the genome of filamentous phage like fs1 may clarify the pathogenesis of cholera toxin negative clinical isolates of Vibrio cholerae O1 and non-O1. Our findings combined with the earlier report by Ehara et al. [Microbio. Immunol. 37 (1993) 679-688] suggest that type 4 fimbriae of Vibrio cholerae O1 are important for the development of an effective vaccine against cholera.

Animals↗

PubMed1997

Conservation of cholera toxin gene in a strain of cholera toxin non-producing Vibrio cholerae O1.

BT23, a Vibrio cholerae O1 E1 Tor isolate, possesses the cholera toxin (CT) gene as determined by PCR. However, CT was not detected in the culture medium by the reversed passive latex agglutination test, nor in the whole cell lysate as examined by Western blotting. The toxin-coregulated pilus (TCP) was not detected by Western blotting. This suggests the presence of defects in the regulatory cascade. toxR, toxS and toxT, members of the regulatory cascade, were examined by PCR. toxR and toxS were conserved but toxT was not. CT and TCP production was complemented by transformation of toxT. The lack of toxT was suspected to be the cause of the undetectable production of CT in strain BT23.

Bacterial Proteins↗

PubMed1997

Molecular epidemiology of Vibrio cholerae O1 isolated from sporadic cholera cases in Okinawa, Japan.

In July 1994, 6 cholera cases due to Vibrio cholerae O1 El Tor Ogawa sporadically appeared in Okinawa. All 6 patients had no history of traveling abroad. In the period of this cholera outbreak, a strain of V. cholerae O1 El Tor Ogawa was detected from an imported fish at the Naha port quarantine station. The isolates were characterized to clarify whether or not, they belonged to a common clone. Phenotypes were identical except that one strain revealed cured Celebes and the others were original Celebes in kappa phage typing. The restriction fragment patterns of DNA of the isolates hybridized with an enzyme-labeled oligonucleotide probe for cholera toxin gene (ctx) were identical. Randomly amplified polymorphic DNA of the isolates were identical when a primer was used, but 2 patterns were seen when another primer was used. Pulsed-field gel electrophoresis of the chromosomal DNA digested with NotI restriction enzyme showed 3 patterns. The DNA fragment pattern of the strain isolated from the imported fish was different from the clinical isolates. These results suggested that there was no epidemiological relation among the strains of V. cholerae O1 isolated during this period.

Animals↗

PubMed1997

Reversed passive latex agglutination assay for detection of toxigenic Corynebacterium diphtheriae.

A reversed passive latex agglutination (RPLA) assay for determining the toxigenicity of Corynebacterium diphtheriae is presented. Rabbit antitoxin antiserum was raised by using commercially available diphtheria toxoid. This antiserum reacted with the diphtheria toxin when the culture supernatant was assayed by Western blotting, and it did not cross-react with other extracellular antigens. Affinity-purified antibodies for latex sensitization were obtained by using a Hi Trap N-hydroxysuccinimide-activated column. Demonstration of toxin in five of seven clinical isolates was in accordance with the PCR assay and the Vero cell cytotoxicity test. Culture of the bacteria for 6 h was sufficient for toxin production, and an additional 6 h was needed to observe latex agglutination. Therefore, diphtheria toxin can be detected in 12 h by this method. The lowest concentration of diphtheria toxin detectable by the RPLA assay was about 5 ng/ml. The RPLA assay can provide a convenient and reliable method for laboratories involved in the identification of toxinogenic corynebacteria.

Animals↗

PubMed1997

Effects of excitative and sedative music on subjective and physiological relaxation.

Previous investigations using heart rate as a measure have not clarified the excitative-sedative effects of music. One of the sources of this failure was considered to be use of the index of heart rate. The present purpose was to examine the excitative-sedative effect of music on indices of the sympathetic and the parasympathetic nervous activities through spectral analysis of heart rate. The presented stimuli were three excitative musical pieces and three sedative ones. Subjective feelings about music were measured by an adjective checklist concerning musical activity. Heart-rate variabilities divided into two components of Low Frequency, mainly affected by the sympathetic nervous system and of High Frequency, mainly affected by the parasympathetic nervous system. Six types of heart-rate indices were employed: (1) mean increments from posttrial base, (2) coefficient of variances of heart rate, (3) mean powers of Low Frequency, (4) coefficient of component variances of Low Frequency, (5) mean powers of High Frequency, and (6) coefficient of component variances of High Frequency. From the factor analysis based on responses to an adjective checklist, there was a single major activity factor. Activity scores showed some were high during excitative pieces and others low during sedative ones. For heart rate, excitative-sedative effects of music were observed only in indices related to High Frequency. This result suggests that musical effect was observed in measures of the parasympathetic nervous system but not in the sympathetic nervous system.

Acoustic Stimulation↗

PubMed1997

A facilitator in self-reported perception of physical symptoms: the role of contingency between physical symptom and aversive event.

Perceptions of physical symptoms are influenced not only by the passive process of physiological stimuli but also by psychological factors such as the contingency between a physical symptom and an aversive event which we examined here in two experiments. 18 subjects in Exp. 1 and 14 subjects in Exp. 2 performed motor tasks. In the Physical condition, an aversive event was contingent on the physical symptom of 'racing heart' in Exp. 1, and on the symptom of 'overstraining shoulder muscles' in Exp. 2. In the Motor condition, an aversive event was contingent on the response of the 'disordered pace of motor tasks' in both experiments. Self-reported scores on attention to and perception of the physical symptoms under the Physical condition were higher than those under the Motor condition. However, there were no differences in the actual physical responses between the two conditions. These results suggest that a contingency between a physical symptom and an aversive event facilitates attention to and perception of the physical symptom.

Adolescent↗

PubMed1996

Re-examination of the local control by nerve growth factor of the outgrowth of neurites in PC12D cells.

We have examined the local control by nerve growth factor (NGF) of the outgrowth of neurites from clonal cells, PC12D, a subline whose phenotype resembles that of the parent PC12 cell line in the NGF-primed state. We show here that (i) the outgrowth of neurites, and their survival can be induced by NGF in enucleated PC12D cells (ii) individual neurites of a single 'giant cell', produced by cell fusion of PC12D cells, can respond independently to the NGF in the local environment, (iii) dissected neurites from giant cells survive for longer in medium that contains NGF than in medium that does not, (iv) in PC12D cells, the rapid formation of ruffles in response to NGF, which appears to be based on increased cell-substratum adhesion, leads to the subsequent formation of neurites, and (v) upon addition of NGF, the movement of short processes displaces polylysine-coated beads in the vicinity of neurites. These observations suggest that the NGF-dependent maintenance or extension of neurites might be controlled within the neurites themselves and might not require the direct involvement of the cell body, even in PC12 cells. It seems possible that any NGF-induced changes that promote an increase in cell-substratum adhesion might be responsible for the initiation and elongation of neurites. It also seems possible that the growth of neurites towards a source of NGF might be based on repeated rounds of extension and retraction of filopodia and neurites in a manner that depends on the concentration of NGF.

Animals↗

PubMed1996

Effect of Vibrio cholerae non-O1 protease on lysozyme, lactoferrin and secretory immunoglobulin A.

The effect of Vibrio cholerae non-O1 protease on host defense proteins (lysozyme, secretory immunoglobulin A and lactoferrin) was studied in relation to its virulence mechanism. The proteins treated with the protease were analysed by SDS-PAGE. There was no influence of the protease on lysozyme. The protease cleaved lactoferrin into two fragments of 50 kDa and 34 kDa. N-terminal amino acid sequencing of these fragments revealed that the cleavage site was near the hinge region, between serine 420 and serine 421. This cleavage could affect the transition from open to closed configuration which is involved in iron binding and release. The anti-bacterial activity of lactoferrin was not affected by protease treatment. Secretory immunoglobulin A yielded a 42-kDa protein as the cleavage product. The susceptibility of secretory immunoglobulin A to V. cholerae non-O1 protease suggests a mechanism by which bacteria might evade the effect of this immunoglobulin.

Amino Acid Sequence↗

PubMed1996

Narrow photon beam dosimetry for linear accelerator radiosurgery.

The dosimetric characteristics of linear accelerator radiosurgery for 10-MV X-ray were measured. Measurement of the relative output factor and tissue maximum ratio with a microchamber produced results equivalent to those of measurement with X-ray film. The 80% isodose level width measured with the microchamber was significantly smaller than that measured with the X-ray film. For the measurement of relative output factor and tissue maximum ratio, a microchamber seems to be the more appropriate choice. X-Ray film was found to be suitable for beam profile measurement.

Phantoms, Imaging↗

PubMed1996

Purification and characterization of a pilus of a Vibrio cholerae strain: a possible colonization factor.

A new flexible type of pilus was purified from Vibrio cholerae non-O1, non-0139 strain NAGV14 and characterized. The molecular mass of the pilin was estimated to be 20 kDa, and the antigenicity differed from that of known pili such as toxin-coregulated pili, mannose-sensitive hemagglutinating pili, V10 pili, and Al-1841 pili. The NAGV14 pilus was regarded as a colonization factor because the purified pili adhered to rabbit intestine and adhesion was inhibited by treating the organisms with the Fab fraction of an antipilus antibody. An intestinal receptor blockade using purified pili failed to inhibit adhesion of the organisms. The NAGV14 pili adhered to the surface of live V. cholerae. An antigen cross-reacting with the NAGV14 pili was widely and specifically distributed among V. cholerae strains irrespective of serotype and biotype. The amino acid sequence of the pilin was homologous with that of MshA. The NAGV14 pili did not agglutinate human and rabbit erythrocytes.

Animals↗

PubMed1996

Test anxiety and working memory system.

The purpose was to examine the effect of test anxiety on deficits in the articulatory loop in the working memory system. We used a verbal memory task to occupy the articulatory loop and a spatial memory task to occupy the visuospatial scratch pad. 17 highly test-anxious and 19 low-anxiety subjects performed both tasks under an anxiety-inducing situation during which they were observed by a monitor camera. Percentage of correct responses and reaction times were measured as indices of task performance. Highly anxious subjects reported feeling worry and cognitive self-concern more than the low-anxiety group. Highly anxious subjects showed a longer mean reaction time on the verbal memory task than the low-anxiety group. On the spatial memory task there was no difference in quality of performance. This finding might suggest that anxiety such as worry and cognitive self-concern interferes with information processing in the articulatory loop of the working memory system.

Achievement↗

PubMed1996

[Traumatic atlanto-occipital dislocation: a case report with survival].

We reported a case of a patient who survived anterior atlanto-occipital dislocation. A seven-year-old girl was admitted to our hospital due to disturbed consciousness after being involved in a traffic accident. With gradual improvement of consciousness, she showed bilateral abducens nerve palsy, quadriparesis and cervical instability. Lateral plain film showed anterior atlanto-occipital dislocation. MRI showed severe compression of the cervical cord and disruption of supporting ligaments of the cervicomedullary junction. After 4 months, cervical instability continued and posterior fixation was carried out with bone grafts. Her postoperative course was uneventful.

Accidents, Traffic↗

PubMed1995

Aberrant gene for E1 Tor hemolysin from Vibrio cholerae non-O1, N037.

Vibrio cholerae non-O1 strain N037 produced a hemolysin (NO37-Hly) which was antigenically similar to E1 Tor hemolysin (E1 Tor-Hly) but different in molecular size, hemolytic activity, and glucose binding capacity. In the gene encoding NO37-Hly, a 4-bp insertion into the structural gene for E1 Tor-Hly (hlyA) was found. The insertion in a shift of codon frames generating a new stop codon in the downstream region. NO37-Hly was a truncated product of E1 Tor-Hly sharing 90% of the N terminal region. This suggested that the 10% C-terminal region of E1 Tor-Hly is needed for the maximal hemolytic activity and glucose binding capacity.

Amino Acid Sequence↗

PubMed1995

The activation and nuclear translocation of extracellular signal-regulated kinases (ERK-1 and -2) appear not to be required for elongation of neurites in PC12D cells.

The outgrowth of neurites was induced in PC12D cells, a subline of PC12 cells, that were treated not only with NGF but also with dbcAMP, staurosporine or bFGF. Simultaneous activation and rapid nuclear translocation of MAP kinases (ERK-1 and ERK-2) were observed in cells treated with NGF or bFGF. But staurosporine and dbcAMP induced no or only slight activation of the kinases. The nuclear translocation of the MAP kinases was not induced by the latter agents. These observations suggest a close relationship between the activation and the nuclear translocation of MAP kinases and, moreover, that stimulation and relocalization of MAP kinases might not be required for the outgrowth of neurites from PC12D cells. Staurosporine and dbcAMP may stimulate a down-stream step of the NGF pathway, or a parallel pathway(s) to the MAP kinase cascade in promoting neurite formation from PC12D cells. These agents mimic the effects of NGF in promoting neurite outgrowth in cultured sympathetic neurons, but not in conventional PC12 cells. Because of the similarity between PC12D cells and primed cells, it seems possible that activation and nuclear translocation of MAP kinases might be required for the transcription-dependent differentiation step but might not be necessary for the elongation of neurites at least in response to staurosporine or to dbcAMP.

Alkaloids↗