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Biomedical subjects

K Wagatsuma

Publications and source records attributed to K Wagatsuma.

At least 19 recordsLinked to original sources
PubMed2001

Application of plasma gas modulation technique for improvement of the measurement of Mn emission intensity in ICP-AES.

A phase-sensitive detection technique associated with a digital lock-in amplifier was applied for an improvement of the detection in ICP-AES. The lock-in amplifier works as an extremely narrow band pass filter. It can pick up the modulated signal, which has the same frequency as the reference signal, from any noise and thus it can improve the signal-to-noise ratio. Modulation of the ICP can be performed by mixing small amounts of air to argon as the outer gas cyclically, because the emission intensities of ionic lines are enhanced by using the mixed gas. An electromagnetic valve, which is placed in the outer-gas flow path, causes periodic variation in the air gas in the outer-gas flow, and thus switching the valve on/off can modulate the ICP. By choosing the appropriate conditions, the addition of air gas enhances the emission intensity of ionic lines more than that of the background, thus leading to improved signal-to-background ratios. At the same time the lock-in amplifier further enhances the ionic emissions because it picks up only the modulated part of the signal. By applying the plasma gas flow modulation technique the detection and the determination limits of the Mn II 257.610 nm line are improved in comparison with the conventional method. A change in plasma shape corresponding to the modulation frequency is observed when the ICP is modulated.

Journal Article↗
PubMed2001

Dissolution of molybdenum-silicon (-boron) alloys using a mixture of sulfuric, nitric and hydrofluoric acids and a sequential correction method for ICP-AES analysis.

For the major component analysis of Mo-Si (-B) alloys by ICP-AES, an appropriate dissolution method is necessary. The general procedure using a HNO3-HF mixture cannot be applied for Mo-Si (-B) alloys due to Si volatilization followed by violent reaction and due to MoO2 precipitation in the preparation of a Mo standard solution from metallic Mo. Good results were obtained with a mixture of 10 mL H2SO4, 1 mL HNO3, 2 mL HF and 12 mL H2O for Mo-Si (-B) alloys. The samples were completely dissolved at room temperature without any losses. A sequential correction method is also suggested to correct several errors in ICP-AES analysis such as fluctuation in the emission intensities, spectral interferences, non-spectral interferences and blank values.

Journal Article↗
PubMed2001

The DD genotype of angiotensin converting enzyme polymorphism is a risk factor for coronary artery disease and coronary stent restenosis in Japanese patients.

Stent implantation has decreased the incidence of restenosis after coronary intervention, but has not eliminated it. The contribution of the angiotensin-converting enzyme (ACE) genotype to the development of coronary artery disease and restenosis after coronary stenting was investigated in 67 Japanese patients in whom 103 lesions in which stents had been successfully implanted were assessed by quantitative coronary angiography, before, immediately after coronary stenting, and during follow-up. The distribution of the patients with the DD, ID, and II genotypes was 13%, 54%, and 33%, respectively. The prevalence of multivessel disease in the DD genotype was significantly higher (DD genotype: 78%; ID genotype: 58%; II genotype: 27%, chi2=8.13, p=0.016) and the late loss in the DD genotype (1.43+/-0.96 mm) was significantly greater (ID genotype: 0.78+/-0.98 mm and II genotype: 0.79+/-0.88 mm, p<0.05 vs DD genotype). However, there was no significant difference in the restenosis rate among the 3 genotypes. The present study in Japanese patients indicates that the DD genotype is associated with more extensive coronary artery disease and progression of the inward remodeling within the stented lesion, which is primarily caused by neointimal hyperplasia.

Aged↗
PubMed2001

Grazing-exit X-ray spectrometry for surface and thin-film analyses.

Electron-probe x-ray micro analysis (EPMA) and particle-induced x-ray emission analysis (PIXE) were performed under grazing-exit conditions. To control the exit angle (take-off angle), a new sample holder having a stepping motor was developed for grazing-exit EPMA. A carefully polished surface of a stainless-steal sample was measured. The surface of stainless steel is normally covered with a thin native oxide layer. The intensity ratio of Cr K(alpha) to Fe K(alpha) increases significantly at the grazing angle, becoming about 5-times larger at 0.2 degrees than at 40 degrees. This result indicates that grazing-exit EPMA is useful for surface analysis. In addition, a new PIXE equipment was developed for grazing-exit x-ray measurements. The sample is fixed and the x-ray detector is moved by applying a linear stage. Preliminary experimental results of grazing-exit PIXE are also shown.

Journal Article↗
PubMed2001

Effect of the driving frequency on the emission characteristics of a radio-frequency glow discharge excitation source boosted by the introduction of a d. c. bias current.

In a radio-frequency-powered glow discharge lamp, a d.c. bias current which is driven by a self-bias voltage can lead to an enhancement of the emission intensities excited by the plasma. The driving frequency of the r.f. plasma is an important parameter to determine the self-bias voltage; lower r.f. frequencies induce greater self-bias voltages. The effects of the bias current introduction on the emission characteristics were compared between a 13.56-MHz plasma and a 6.78-MHz plasma. As a result, the 6.78-MHz plasma offered a better analytical performance, probably due to higher self-bias voltages, if the introduced Ar pressure was optimized. This method was applied to a Mo determination in Fe-matrix alloy samples. At bias currents of 40 - 50 mA, the emission intensities of the Mo I 379.82-nm line were about 10-times larger than those obtained with the conventional plasma when the 6.78-MHz plasma was produced at an r.f. power of 60 W. The detection limit obtained for this calibration was 2.0 x 10(-4) mass % Mo at an 80-W r.f. power and at a d.c. bias current of 68 mA.

Journal Article↗
PubMed1997

Percutaneous transluminal coronary angioplasty for morphologic left anterior descending artery lesion in a patient with dextrocardia. A case report and literature review.

A case report of percutaneous transluminal coronary angioplasty (PTCA) to treat coronary atherosclerotic lesions in a patient with dextrocardia associated with situs inversus totalis is presented. The patient was a sixty-two-year-old man who was admitted with a diagnosis of congestive heart failure. Cardiac catheterization was performed. Left ventriculography showed mild hypokinesis in segments 2 and 3 with ejection fraction of 63%. Coronary arteriography revealed 74% stenosis in segment 7 of the left anterior descending (LAD) artery. PTCA for this lesion was performed. Successful dilation was achieved with the residual stenosis in the LAD reduced from 74% to 34%. Performance of PTCA in patients with dextrocardia is extremely rare, and only 8 cases have been reported to date. However, by visualizing the procedure as a mirror image and choosing a guide catheter that permits good engagement, it appears possible to perform it like ordinary PTCA.

Angioplasty, Balloon, Coronary↗
PubMed1997

A case of favorable dilation of protected left main coronary artery lesion achieved through performance of adjunctive DCA on residual stenosis following use of rotablator.

It is believed that directional coronary atherectomy (DCA) is more suitable than percutaneous transluminal coronary angioplasty for lesions such as severe eccentric lesions, ostial lesions, and branch lesions. However, it remains a fact that lesions that are also highly calcified are often suboptimal, since there may be difficulties such as in insertion of the housing and in sufficient cutting and removal. On the other hand, Rotablator is effective on calcified lesions, but afterward, dilation by balloon angioplasty for residual stenosis becomes necessary in many cases. This is a report of the authors' experience on an interesting case in which favorable dilation of a lesion in the protected left main coronary artery (LMCA) was achieved by using Rotablator after confirmation of a high degree of calcification by means of intravascular ultrasound (IVUS) echocardiograhy, followed by the performance of DCA on the residual stenosis.

Angioplasty, Balloon↗
PubMed1996

Excitation of singly-ionized argon species in helium-matrix Grimm glow discharge plasmas II - Comparison between argon and neon.

A considerable intensity enhancement of several Ar II lines assigned to the 3p(4)4p-3p(4)4s transition in a helium-argon Grimm glow discharge plasma has been previously reported and attributed to argon ions excited by metastable helium atoms. In this paper the behavior of Ne II lines assigned to the 2p(4)3p-2p(4)3s transition in a helium-neon plasma was investigated to obtain detailed information on the excitation of plasma gases in the helium-matrix plasmas. No Ne II lines with enhanced emission intensities have been found; on the contrary, the intensities of the doublet Ne II lines decreased in the helium-matrix plasma.

Journal Article↗
PubMed1995

Efficacy and issues of emergent percutaneous transluminal coronary angioplasty. Comparison of clinical results in younger and elderly patients.

The authors investigated the efficacy and prognosis of emergency percutaneous transluminal coronary angioplasty (PTCA) in elderly patients. A study was conducted on the early and late prognosis of the study group composed of 66 younger patients < sixty-five years in Group A and 46 elderly patients > or = seventy years in Group B who underwent reperfusion therapy, including PTCA, for acute myocardial infarction (AMI). No difference was seen in the initial success rate of 82% for Group A and 85% for Group B, or in the vessel patency in the predischarge coronary arteriogram (CAG) with 84% for Group A and 87% for Group B. However, in-hospital mortality was 3% for Group A and 11% for Group B. The patient restenosis rate in the 4.2 months follow-up CAG was 28% for Group A and 50% for Group B. The lesion restenosis rate was 30% for Group A and 53% for Group B (P < 0.05), and the late period mortality rate was 3% for Group A and 11% for Group B. Although there was no difference in the initial success rate of reperfusion through PTCA for AMI in the elderly as compared with the younger patient group, poorer results were seen in the restenosis rate and mortality rate.

Age Factors↗
PubMed1995

[A study of the efficacy of thrombolytic therapy for acute myocardial infarction in elderly patients].

We compared the short and long term outcome between an elderly group (E; aged 70 year more, 17 cases) and a younger group (Y; less than 70 years, 95 cases). Reperfusion rates were similar in both groups (E; 70.6% vs Y; 67.3%). Reocclusion rates at predischarge CAG were similar in both groups (E; 70.6% vs Y; 67.3%). Reocclusion rates at predischarge CAG were similar in both groups (E; 7.2% vs Y; 6.8%). Hospital cardiac deaths in E were higher than Y (E; 5.9% vs Y; 4.2%). Intestinal bleeding in E was more frequent than in Y (E; 5.9% vs Y; 3.2%). We concluded that thrombolytic therapy for acute myocardial infarction in elderly patients was useful, however bleeding complication in elderly patients were higher than in younger patients.

Aged↗
PubMed1995

[Two cases of peripartum cardiomyopathy].

Two cases of peripartum cardiomyopathy, a rare type of dilated cardiomyopathy, are reported. A 36-year-old woman developed congestive heart failure 1 month after delivering her third child. Cardiac catheterization revealed diffuse hypokinesis of the left ventricle and an ejection fraction of 28%. The second study, 20 months later, demonstrated an ejection fraction of 46%. Endomyocardial biopsy showed mild interstitial edema. A 42-year-old woman developed toxemia during pregnancy. She delivered her second child at 38 weeks of gestation. Two weeks later, she developed congestive heart failure. Cardiac catheterization demonstrated diffuse hypokinesis of left ventricle with an ejection fraction of 40%. Endomyocardial biopsy revealed dense fibrosis. Follow-up angiography performed 8 months later showed similar findings with an ejection fraction of 34%. These two cases suggest the importance of evaluation of endomyocardial biopsy to determine the degree of interstitial fibrosis that may reflect the prognosis for patients with peripartum cardiomyopathy confirmed by measurements of ejection fraction.

Adult↗
PubMed1994

Immunohistochemical localization of cytokeratins and involucrin in calcifying epithelioma: comparative studies with normal skin.

The expression of cytokeratins and involucrin varies greatly in different epithelia, and this raises the possibility that detailed analysis of these epidermal proteins might provide a means of identifying various skin tumours. The present study was conducted to determine the immunohistochemical distribution of cytokeratins and involucrin in calcifying epithelioma of Malherbe, in order to elucidate the nature and differentiation of this tumour. To correlate the immunohistochemical profile with the most frequent histological patterns, we categorized the basophilic, transitional, shadow, and squamoid cells, and the shreds of keratin. Comparative studies with normal skin showed that the shadow and transitional cells corresponded to hair cortex cells, the squamoid cells to the outer root sheath, the basophilic cells adjacent to the stroma to the outermost cell layer of the outer root sheath between the lower permanent portion and upper transient portion of the follicles, and the basophilic cells adjacent to the transitional cells to the hair matrix. The expression of cytokeratins in most shreds of keratin was similar to that in squamoid cells. Calcifying epithelioma was, therefore, shown to be composed of tumour cells differentiating into both the hair cortex and outer root sheath. These tumour cells were differentiated from basophilic cells, which showed the same staining patterns as the outermost cell layer of the outer root sheath between the lower permanent portion and upper transient portion of the hair follicles, supporting the hypothesis that the keratinocytes in the outermost cell layer can differentiate into the transitional portion of the follicle and anagen hair.

Adolescent↗
PubMed1991

Abnormal distribution of epidermal protein antigens in psoriatic epidermis.

The immunohistochemical distribution of the epidermal proteins filaggrin, involucrin, and cytokeratins is characteristic in normal epidermis. This distribution may change as a result of malignant transformation or abnormal differentiation. The present study was conducted to determine the patterns of reactivity of psoriatic epidermis to antibodies against various epidermal proteins and to clarify abnormal differentiation or maturation of the keratinocytes in psoriatic epidermis. Anti-human filaggrin, anti-human involucrin, and twelve kinds of anti-cytokeratin antibodies were used in this study. Cryostat or paraffin-embedded sections were stained with these antibodies by the avidin-biotin peroxidase technique. The epidermis of the noninvolved skin of patients with psoriasis vulgaris showed the distribution seen in normal skin. However, involved psoriatic skin revealed little or no reaction in the stratum corneum or in the granular layer with the anti-filaggrin antibody. Cells positively staining with anti-involucrin antibody paradoxically appeared in the lower cell layers of involved psoriatic epidermis. An anti-keratin antibody, AE1, stained suprabasal cells in involved psoriatic epidermis, although this antibody selectively stained epidermal basal cells in normal skin. The other anti-keratin antibodies, especially KL1, PKK1, and a polyclonal anti-keratin antibody, were less reactive with involved psoriatic skin than with normal skin. These observations suggest that the maturation pathway of keratinocytes in active psoriatic lesions differs qualitatively from that in normal epidermis.

Adolescent↗
PubMed1991

Monoclonal antibody OKB19, reactive with a B-lymphoid differentiation antigen (CD19), binding to basal layer keratinocytes of normal human skin.

Monoclonal antibody (moAB) OKB19 reacts with CD19 antigen, which is the broadest lineage-specific surface marker on B-lymphocytes. In frozen tissue sections, using an immunohistochemical technique, the OKB19-positive cells in the basal layer were sharply demarcated from the negative suprabasal layers. In normal hair follicles, the OKB19 reactivity was also confined to one layer of the dermal side of the outer root sheath. However, this reactivity gradually disappeared in the lower areas. The inner surface of the lumina in the eccrine duct was weakly stained with OKB19. The basal keratinocytes were also stained with OKB19 in the lesional epidermis of the various dermatoses examined in this study, when the basal keratinocytes remained unaffected. Even in the hyperproliferative state of psoriasis, the OKB19 reactivity was confined to the basal layer. Several kinds of tumor cells derived from the skin were not stained with OKB19. No labeling was seen even in the basaloid cells of basal cell carcinoma, which are morphologically similar to basal keratinocytes. B4 and Leu-12, other monoclonal antibodies reacting with CD19, did not recognize any keratinocytes in the normal human skin. MoAB OKB19, therefore, reacts with an antigen present on basal keratinocytes and provides a probe for the isolation of the basal keratinocyte subpopulation. Thus, this antibody should be useful in studies of not only B-lymphocyte differentiation, but also normal and aberrant differentiation of the epidermal keratinocytes.

Antibodies, Monoclonal↗
PubMed1991

Hair growth on nude mice due to cyclosporin A.

One of the most common dermatological side effects of cyclosporin A (CsA) is dose-dependent hypertrichosis. Similar hair growth was noted in nude mice in an attempt to increase the acceptance of human xenografts with CsA in the T-cell-deficient congenitally athymic nude (nu/nu) mice. The aim of the present study was to further investigate the stimulation of hair growth on nude mice not only by oral administration of CsA but also by topical and subcutaneous administration of CsA. Young BALB/c female nude mice were treated for 3 or 4 weeks with topical, oral, or subcutaneous applications of CsA dissolved in olive oil at various doses. The hair of CsA-treated mice appeared to grow from 7 days after the treatment, even at low doses. Induced hair growth was dose-dependent and became clearly obvious 3 weeks after the treatment. The stimulation of hair growth was not restricted to the site of topical application. The distribution of the new hair depended on the natural pattern of hair growth in the mice. However, there was no hair growth in the control mice which were given only olive oil. Histological examination revealed that there were no differences in the structures of skin and hair between the control and the CsA-treated mice. Furthermore, the number of hair follicles did not remarkably increase after CsA treatment. The hair growth in the CsA-treated mice stopped after cessation of the treatment and returned to the level of the control mice on day 14 after the end of the treatment. Subsequent retreatment with CsA resulted in further regrowth of the hair.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1988

A pitch-synchronous analysis of hoarseness in running speech.

A method of pitch-synchronous acoustic analysis of hoarseness requiring a voice sample of only four fundamental periods is presented. This method calculates a noise-to-signal (N/S) ratio, which indicates the depth of valleys between harmonic peaks in the power spectrum. The spectrum is calculated pitch synchronously from a Fourier transform of the signal, windowed through a continuously variable Hanning window spanning exactly four fundamental periods. A two-stage procedure is used to determine the exact duration of the four fundamental periods. An initial estimate is obtained using autocorrelation in the time domain. A more precise estimate is obtained in the frequency domain by minimizing the errors between the preliminary calculated power spectrum and the predicted spectrum spread of a windowed harmonic signal. Analysis of synthesized voices showed that the N/S ratio is sensitive to additive noise, jitter, and shimmer, and is insensitive to slow (8 Hz) modulation in fundamental frequency and amplitude. An analysis of pre- and postoperative voices of six patients with benign laryngeal disease showed that the N/S ratio for vowel /u/ in running speech consistently improved after surgery for all subjects, in agreement with their successful therapeutic results.

Hoarseness↗