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Biomedical subjects

M Yamagiwa

Publications and source records attributed to M Yamagiwa.

At least 19 recordsLinked to original sources
PubMed2006

Laser ion-acceleration scaling laws seen in multiparametric particle-in-cell simulations.

The ion acceleration driven by a laser pulse at intensity I= 10(20)-10(22) W/cm(2) x (microm/lambda)(2) from a double layer target is investigated with multiparametric particle-in-cell simulations. For targets with a wide range of thickness l and density n(e), at a given intensity, the highest ion energy gain occurs at certain electron areal density of the target sigma = n(e)l, which is proportional to the square root of intensity. In the case of thin targets and optimal laser pulse duration, the ion maximum energy scales as the square root of the laser pulse power. When the radiation pressure of the laser field becomes dominant, the ion maximum energy becomes proportional to the laser pulse energy.

Journal Article↗
PubMed2006

Electron, positron, and photon wakefield acceleration: trapping, wake overtaking, and ponderomotive acceleration.

The electron, positron, and photon acceleration in the first cycle of a laser-driven wakefield is investigated. Separatrices between different types of the particle motion (trapped, reflected by the wakefield and ponderomotive potential, and transient) are demonstrated. The ponderomotive acceleration of electrons can be largely compensated by the wakefield action, in contrast to positrons and positively charged mesons. The electron bunch energy spectrum is analyzed. The maximum upshift of an electromagnetic wave frequency during reflection from the wakefield is obtained.

Journal Article↗
PubMed2001

Binding properties of Bacillus thuringiensis Cry4A toxin to the apical microvilli of larval midgut of Culex pipiens.

Cry4A is a dipteran-specific delta-endotoxin produced by Bacillus thuringiensis, and toxic to Culex pipiens (mosquito) larvae. The immunohistochemical staining of the midgut sections of C. pipiens larvae revealed that Cry4A bound in vitro and in vivo to the microvilli of the epithelial cells of posterior midgut and gastric caecae. The binding of digoxigenin-labeled Cry4A (DIG-Cry4A) to the apical microvilli was almost abolished in the presence of excess unlabeled Cry4A, suggesting that the binding of Cry4A to the microvilli was specific. Several Cry4A-specific binding proteins were detected using the ligand blotting technique with DIG-Cry4A. Moreover, an insertion assay was done, where the binding of DIG-Cry4A to the BBMVs was completely irreversible and did not compete with excess unlabeled Cry4A. On the basis of these results, we propose a schematic interpretation for the binding process of Cry4A.

Animals↗
PubMed2000

[Relationship between intensity of annoyance due to throat discomfort and psychological test results].

For 87 male and 100 female patients (average age of 58.5 years) with throat discomfort, we investigated the relationship between the intensity of annoyance caused by throat discomfort and psychological distress. We asked patients to assess their throat discomfort using a 100-mm horizontal visual analogue scale (VAS) which defined the left end (0) as no annoyance and the right end (100) as overwhelming annoyance attributed to throat discomfort. The extent of their psychological distress was evaluated by 3 tests: Cornell Medical Index-Health Questionnaire (CMI), Self-rating Depression Scale (SDS) and Self-rating Questionnaire for Depression (SRQ-D). Our results indicate that the increase in intensity of annoyance caused by throat discomfort was significantly related to the increase in somatic symptoms (Spearman's rho = 0.164, p = 0.025), symptoms connected to autonomic nerve dysfunction (rho = 0.203, p = 0.006) as measured by CMI and neurotic condition as classified by Fukamachi's diagnostic method for CMI (p = 0.049 by Kruskal-Wallis test). The increase in intensity of annoyance caused by throat discomfort was significantly related to the increase in depressive condition as measured using SRQ-D (rho = 0.263, p < 0.001), but not to that measured using SDS (rho = 0.097, p = 0.185). The results obtained from the present study indicate that VAS is a useful tool for measuring annoyance caused by throat discomfort, yielding valuable information about the intensity of patients' somatic and psychological complaints.

Adolescent↗
PubMed1999

Ion explosion and multi-mega-electron-volt ion generation from an underdense plasma layer irradiated by a relativistically intense short-pulse laser.

Ion acceleration and expansion in the interaction of a relativistically intense short-pulse laser with an underdense plasma layer are investigated. Ion and electron dynamics are studied by a two-dimensional particle-in-cell simulation with the real mass ratio. It is shown that the longitudinal electric field induced by electron evacuation due to a large ponderomotive force or light pressure can accelerate ions to several MeV in the direction of the laser propagation. It is after the laser completely passes through the plasma layer that the ion explosion starts to be significant.

Journal Article↗
PubMed1999

Activation process of dipteran-specific insecticidal protein produced by Bacillus thuringiensis subsp. israelensis.

Dipteran-specific insecticidal protein Cry4A is produced as a protoxin of 130 kDa in Bacillus thuringiensis subsp. israelensis. Here we performed the in vitro processing of Cry4A and showed that the 130-kDa protoxin of Cry4A was processed into the two protease-resistant fragments of 20 and 45 kDa through the intramolecular cleavage of a 60-kDa intermediate. The processing into these two fragments was also observed in vivo. To investigate functional properties of the two fragments, GST (glutathione S-transferase) fusion proteins of the 60-kDa intermediate and the 20- and 45-kDa fragments were constructed. Neither the GST-20-kDa fusion protein (GST-20) nor the GST-45-kDa fusion protein (GST-45) was actively toxic against mosquito larvae of Culex pipiens, whereas the GST-60-kDa intermediate fusion protein (GST-60) exhibited significant toxicity. However, when the two fusion proteins GST-20 and GST-45 coexisted, significant toxicity was observed. The coprecipitation experiment demonstrated that the two fragments associated with each other. Therefore, it is strongly suggested that the two fragments formed an active complex of apparently 60 kDa. A mutant of the 60-kDa protein which was apparently resistant to the intramolecular cleavage with the midgut extract of C. pipiens larvae had toxicity slightly lower than that of GST-60.

Amino Acid Sequence↗
PubMed1998

Nasal passage patency in patients with allergic rhinitis measured by acoustic rhinometry: nasal responses after allergen and histamine provocation.

We investigated nasal passage patency after allergen and histamine provocation in patients with allergic rhinitis by acoustic rhinometry. In total, 75 outpatients with allergic rhinitis were studied. The threshold of nasal hypersensitivity to histamine was measured by the 10 microliters instillation of serial 10-fold dilution in the ipsilateral nasal cavity. Nasal provocation testing to specific antigen was applied to the anterior part of inferior turbinate in bilateral sides in sitting position. Measurement of nasal patency by acoustic rhinometry was repeated three times in each nasal cavity. The minimal cross-sectional area and total volume of nasal cavity were measured in an individual subject. The minimal cross-sectional area and total volume in the histamine challenged-side significantly decreased on the 10(-2), 10(-1), 10(-0) of end point, and up to 30 min after challenge with the threshold dose, but not in the unchallenged side. This means acoustic reflection technique is sensitive at least 100-fold in comparison with classical method like findings by anterior rhinoscopy and symptom scores. Nasal passage patency after bilateral allergen provocation showed predominant in the unilateral side, suggesting the cross over-reflex effects. It was concluded that acoustic rhinometry is one of the highly quantitative and sensitive method which can observe the change of nasal congestion.

Adolescent↗
PubMed1997

Identification of a second transcriptional start site for the insecticidal protein gene cryIVA of Bacillus thuringiensis subsp. israelensis.

Expression of cryIVA, one of the insecticidal protein genes of B. thuringiensis subsp. israelensis, is regulated at the transcriptional level. The cryIVA gene is specifically transcribed during the stationary phase of this bacterium. As shown in our previous report [Yoshisue et al. (1993a)], the transcription from the -364 position of the cryIVA gene is conducted by the major promoter P1 that is functional during middle stages of the stationary phase of B. thuringiensis. In the present study, we have identified a second transcriptional start point P2 for the cryIVA gene in addition to P1, the major transcriptional start point. The transcription from P2 of the cryIVA gene occurred later than that from P1, during later stages of stationary phase of B. thuringiensis subsp. israelensis. The -10 and -35 nt sequences upstream from P2 of cryIVA are similar to those of the omega 28-specific promoters of B. thuringiensis genes and of the omega K-specific promoters of B. subtilis genes. It is most likely that the region upstream from P2 of cryIVA contains the nt sequences that determine the omega 28-specific promoter, the second one, for the cryIVA gene.

Amino Acid Sequence↗
PubMed1997

Acoustic evaluation of the efficacy of medical therapy for allergic nasal obstruction.

Acoustic rhinometry (AR) was used for objective measurements of nasal cavity dimensions in conjunction with a 100-mm horizontal visual analogue scale (VAS) for simultaneous subjective assessments of nasal sensations of airflow. Studies were conducted on 45 patients with perennial allergic rhinitis before, during and after a 2-week period of treatment with oral emedastine difumarate, azelastine hydrochloride, and xiao qing long tang (a homeopathic decongestant), as well as intranasal fluticasone propionate aqueous nasal spray. During the treatment period, there was a significant increase in the right and left minimum cross-sectional areas (MCA) of the nose and/or nasal cavity volumes (NCV) in all groups. The average increase in MCA ranged from 21-39% after 1 week of treatment and 16-39% after 2 weeks, whereas that in the NCV ranged from 16-24% and 19-24%, respectively. Post-treatment measurements were not significantly different from the corresponding pre-treatment ones. These findings were in close agreement with that obtained with VAS, demonstrating that AR can be used to validate the application of VAS in the evaluation of nasal airflow during medical therapy.

Acoustics↗
PubMed1995

[Abnormal sensation in the throat and autonomic nerve dysfunction symptoms].

Abnormal sensations, such as a lump, itchiness or choking, in the throat (AST) may develop as symptoms of autonomic nerve dysfunction (AND). If this is true, the subjects with AST should show more subjective symptoms and objective signs of AND than those without AST. We classified 500 otolaryngological and neurological patients [172 males and 328 females, age 58.4 +/- 14.0 years (mean +/- SD)] with various signs and symptoms suggesting autonomic nerve dysfunction into 2 groups: 370 patients with AST (AST group) and 130 without AST (non-AST group). For the subjective evaluation of AND symptoms, we calculated the number of positive answers to 33 questions concerning AND symptoms which appear in the Cornell Medical Index (Health Questionnaire). Objective evaluation of AND was done by analyzing the coefficient of variation (%) of 100 R-R intervals on electrocardiograms [CV R-R (%)], as previous studies by others have shown that CV R-R (%) decreases with age and/or with the severity of autonomic nerve dysfunction. The following results were obtained in the comparison between the two groups. 1) There were significantly more complaints of AND symptoms in the AST group (7.3 +/- 5.5, mean +/- SD) than in the non-AST group (5.3 +/- 4.4) (p < 0.0005 by Wilcoxon test). 2) The relative CV R-R (%) value calculated by dividing the CV R-R (%) actually obtained by the formula [5.13 - 0.0419 x age of subject (years)] was significantly smaller in the AST group (0.98 +/- 0.40) than in the non-AST group (1.06 +/- 0.39) (p < 0.05 by Wilcoxon test).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Nasal cavity dimensions in the newborn measured by acoustic reflections.

The acoustic reflections technique was used to measure nasal cavity dimensions in 27 newborns. The results were expressed in terms of curves describing cross-sectional area as a function of the distance into the nose. From these curves, a mean curve with 95% confidence limits, nasal cavity volumes between the nostril and 4.5 cm into the nasal cavity (V45 = 1.05 (0.24) cm3), the cross-sectional area at the narrowest site (Amin = 0.114 (0.033) cm2), and the distance from the nostril to Amin (DAmin = 1.14 (0.47) cm), expressed as mean and SD were calculated. There was a weak correlation between Amin and length and weight at birth, but otherwise nasal cavity dimensions did not correlate with sex, race, birth weight, birth length, head circumference, or duration of gestation. Comparison of the curves from the newborns with curves from adults showed a facial growth in vertical/transverse directions (area) of 600% and anterior/posterior directions of 120%. The technique of acoustic rhinometry is noninvasive, and can be performed rapidly, and is therefore eminently suitable for pediatric application. Further investigations are needed to demonstrate the value as a diagnostic tool in pathological cases.

Acoustics↗
PubMed1994

[Evaluation of throat discomfort with visual analogue scale (VAS)].

We adopted a visual analogue scale (VAS) to evaluate discomfort like the sensation of a choking lump in the throats of 92 patients (24 male and 68 female, 17-80 years of age) who consulted us complaining of the sensation. The VAS consisted of a 100 mm long horizontal straight line defined by anchors with verbal labels: the left end point (0 mm) indicated no throat discomfort, the right end point (100 mm) overwhelming throat discomfort. We determined the VAS score (1 mm = 1) by measuring the distance from the left end point to the mark made by the patient. On the first day of the study, the patients evaluated the sensation with the VAS alone. One, two and three weeks later they evaluated the sensation with the scale, and at the same time, they were asked to compare the strength of the existing sensation with that on the first experimental day and to express the percent change in the sensation. The latter data were used for calculation of the predicted VAS score. It was neither difficult nor time-consuming for the patients, some of whom were fairly elderly, to display the strength of the sensation on the scale. The VAS score on the first day of the study for each patient ranged from 6-92, and the mean and the standard deviation were 44.6 and 21.0, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Inhalation of diethylamine--acute nasal effects and subjective response.

Adult volunteers were exposed to 25 ppm (75 mg/m3) diethylamine in a climate chamber for 15 min in order to study the acute nasal reactions to an exposure equivalent to the present threshold limit value-short-term exposure limit. Changes in nasal volume and nasal resistance were measured by acoustic rhinometry and by rhinomanometry. Acute change in nasal volume, usually seen as acute nasal mucosa response to thermal stimuli, was not observed, nor was an acute change in nasal airway resistance. In a subsequent experiment, the aim was to measure acute sensory effects. Exposure to a concentration increasing from 0 to 12 ppm took place for 60 min, equal to an average concentration of 10 ppm (30 mg/m3). A moderate to strong olfactory response and distinct nasal and eye irritation were observed. In spite of considerable individual variation, the results were in agreement with sensory effect estimates obtained from animal studies.

Acoustics↗
PubMed1991

[Ala1,3,11,15]endothelin-1 analogs with ETB agonistic activity.

A linear peptide analog of endothelin (ET)-1, [Ala1,3,11,15]ET-1 (4AlaET-1), and its truncated peptide analogs were synthesized to study the structural requirements of ET-1 for the recognition of ETs-nonselective ETB receptors. ET-1 exhibited sub-nanomolar binding to two distinct ET receptor subtypes (ETA and ETB), but 4AlaET-1 bound to ETB with an affinity 1,700 times higher than that seen during binding to ETA. The truncated linear peptides 4AlaET-1(6-21), 4AlaET-1(8-21) and N-acetyl-4AlaET-1(10-21) still had high affinity for ETB, whereas 4AlaET-1(6-20) and 4AlaET-1(11-21) displayed remarkably reduced affinity for ETB. Therefore, ET-1 requires the Glu10-Trp21 sequence for ETB binding, but not the disulfide bridges. These ETB-binding peptides elicit endothelium-dependent vasorelaxation of porcine pulmonary arteries in parallel with the binding affinity for ETB, suggesting that they are ETB agonists.

Amino Acid Sequence↗
PubMed1991

[Psychological states and personality as factors in the morbidity of head and neck malignant tumors].

Many publications have repeatedly indicated that there seems to be a correlation between neoplastic disease and certain types of psychological situations. However, such studies subjected malignant tumors in head and neck region are scanty so far. We applied Cornell Medical Index Health Questionnaire (CMI) and Maudsley Personality Inventory (MPI) to collect medical and psychiatric data from 86 patients (56 males and 30 females) with head and neck malignant tumors and 115 control patients (73 males and 42 females) with head and neck diseases other than malignant tumors. Analysis of CMI data using Diagnostic Sheet, Fukamachi's method and Modification of Abe's method, and analysis of each of Extroversion-Introversion scale scores, Neuroticism scale scores and Lie scale scores of MPI led the following conclusion. 1) Both male and female patients with head and neck malignant tumors showed to be more depressive than their control patients were. Especially, between the two patient groups in males, there was a statistically significant (p less than 0.05) difference. 2) Regarding neurosis, autonomic nerve dysfunctioning and extroversion-introversion, none of these factors seemed to be related with the morbidity of head and neck malignant tumors. Further exploration of this issue, with a special attention to the relationship between depression and head and neck malignancy should be conducted, if possibly, from a prospective point of view.

Adult↗
PubMed1991

[Effect of recognition of head and neck malignancies on patients' psychosomatic condition and personality].

In order to elucidate the effect of recognition of head and neck malignancies on patients' psychosomatic condition and personality, we applied the Cornell Medical Index Health Questionnaire (CMI) and the Maudsley Personality Inventory (MPI) and collected medical and psychological data from 35 male (42-78 years of age; average 62.5) and 15 female (20-76 years of age; average 54.7) patients with malignant head and neck tumors (10 nose and paranasal, 8 oral, 8 pharyngeal, 14 laryngeal, 6 thyroid gland and 4 others). The two tests were done twice for each patients; at first immediately before hospitalization for treatment of the tumors at Mie University Hospital and secondly just before discharge from the hospital. The period of hospitalization ranged 1 to 13 months, average 3.3 months. At the end of hospitalization doctors and nurses who had mainly taken care of the patients estimated the patients' recognition of their malignancy by analyzing behavior and information mainly from their family and classified patients into three groups; Group R (Patients who recognized that they were patients with head and neck malignancies) comprised 22 patients, Group N (who did not recognize the condition) comprised 15 and Group U (who could not be classified into Groups R or N) comprised 13. Comparison among the three groups revealed the followings. 1) Patients in Group R were relatively young (average 56.3 years) and extrovert (estimated by MPI) and their somatic and psychological complaints registered on the CMI were less than those in other 2 groups. Psychosomatic condition after recognition that they had been patients with malignant tumors was better than before.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Clinical effects and toxicity of chemotherapy with cisplatin for head and neck cancer--the multi-institutional joint research in Tokai district].

We investigated the clinical effects and toxicity of chemotherapy with Cisplatin (CDDP) for head and neck cancer as the third joint research project of the Tokai Meeting for Head and Neck Tumors. The cases were examined at the cooperating institutions from September 1986 to March 1988. The subjects were 93 cases consisting of 66 patients (intravenous infusion: 47 cases; intraarterial infusion: 19 cases) of PP therapy (CDDP + PEP), 16 cases of PF therapy (CDDP + 5-FU) and 11 cases of PPV therapy (CDDP + PEP + VCR). The regimens of PP therapy were: CDDP 50-100 mg/body x 1 day, PEP 5 mg/body x 5 days (i.v.), and CDDP 10-20 mg/body x 5 days, PEP 5-10 mg/body x 5 days (i.a.). In the regimen of PF therapy, CDDP 80-100 mg/body x 1 day and 5-FU 750-1,000 mg/body x 5 days were administered. In the regimen of PPV therapy, CDDP 80-100 mg/body x 1 day, PEP 5 mg/body x 5 days and VCR 1 mg/body x 1 day were administered. As a rule, two courses of each of the regimens were performed. The total dose of CDDP in intraarterial infusion of PP therapy was significantly less than in intravenous infusion. The major results were as follows: 1) Total response rate was 57.0% on the average, and this was not significantly different among the regimens. 2) The response rate of intraarterial infusion of PP therapy was as high as that for intravenous infusion in spite of the lower CDDP dose. 3) The response rate of oral cavity was significantly higher than that of nasal cavity and paranasal sinuses. 4) In the squamous cell carcinoma, the response rate of the well differentiated type was significantly higher than that of the poorly differentiated type. 5) The leukocyte counts significantly decreased with the intravenous infusion of PP therapy, PF therapy and PPV therapy. 6) The platelet counts significantly decreased with PPV therapy. 7) There were no significant changes with time with Ccr and PaO2 of PP therapy. 8) The frequency of toxicities such as nausea and vomiting was high in the intravenous infusion of PP therapy, PF therapy and PPV therapy. However, the frequency of toxicity was low in the intraarterial infusion of PP therapy.

Adult↗