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Biomedical subjects

K Shikano

Publications and source records attributed to K Shikano.

At least 19 recordsLinked to original sources
PubMed1999

Direct preparation of radioactive fullerenes as a tracer for applications.

The C60 and C70 fullerenes were irradiated by high-energy gamma-rays and charged particles. The irradiated samples were dissolved in CS2 and/or toluene and filtered to remove insoluble by-products. Finally, radioactive fullerenes and products labeled with 11C or 13N were isolated and detected in the liquid phase by radiochromatography. It was found that (1) not only 11C or 13N radioactive monomer fullerenes but also their dimers (trimers and, possibly, tetramers) were produced by recoil implantation process following nuclear reaction and (2) the radioactive fullerene labeled with 11C yields has led to high yields.

Carbon↗
PubMed1993

The correlation between HPV infection and cell proliferative activity in uterine cervical adenocarcinoma.

To investigate the correlation between human papillomavirus (HPV) infection and cell proliferative activity in uterine cervical adenocarcinoma, in situ hybridization of HPV DNA and immunostaining of proliferative cell nuclear antigen (PCNA) were performed on serial sections of the carcinoma. HPV 16 and 18 DNA was detected in 10 of 33 cases of cervical adenocarcinoma and adenocarcinoma in situ. PCNA was detected in 30 cases. In all 10 HPV-positive cases, PCNA was also demonstrated, and the number of PCNA-positive cells tended to be higher than that in HPV-negative cases. With 1:1 correlation between HPV and PCNA on the nuclei, the coincidence rate was 72% (p < 0.01). These results indicate that HPVs play a role in cell proliferation.

Adenocarcinoma↗
PubMed1993

Measurement of myocardial blood flow in coronary artery bypass surgery.

It is now possible experimentally to measure myocardial blood flow of the beating heart using a helium-neon (He-Ne) laser Doppler flowmeter. A myocardial probe was redesigned to reduce its size and weight, and a method devised of fixing the probe to the beating cardiac surface to allow its clinical application. This modified laser flowmeter was used on 36 patients with ischaemic heart disease to measure myocardial blood flow before and after revascularization. Flow was measured in the right and left ventricles while patients were in a haemodynamically stable state as determined by electrocardiography, heart rate, blood pressure and double product (heart rate x systolic blood pressure). No significant difference was found between the mean(s.e.m.) preoperative and postoperative flow volume at the anterior wall of the right ventricle (77(15) versus 81 (12)ml/min per 100 g), which did not undergo revascularization, but mean(s.e.m.) myocardial blood flow at the ischaemic left ventricle increased significantly (from 68(15) to 88(13) ml/min per 100 g; P < 0.01). There was also no significant difference between preoperative and postoperative values of haemodynamic parameters of coronary blood flow. In conclusion, a means to measure myocardial blood flow with He-Ne laser Doppler flowmetry has been devised which shows coronary artery bypass grafting to increase myocardial blood flow in the ischaemic myocardium.

Adolescent↗
PubMed1993

[Selective cerebral perfusion and pharmacological cerebral protection in the patients with aortic arch aneurysm].

We have developed the protocol for selective cerebral perfusion (SCP) and pharmacological cerebral protection, and used it successfully in cases of aortic arch aneurysm. The subjects of the present study were 34 patients (28 males, 6 females) whose aortic arch aneurysm were surgically treated. Preoperative brain CT and brain scintigram showed high incidence of brain ischemia. However only 4 patients experienced a neurological episode. We conclude that our SCP technique and pharmacological cerebral protection are useful component to surgery of the aortic arch.

Adult↗
PubMed1992

[Recent advances in EDRF research].

We have developed a new bioassay system for endothelium-derived relaxing factor (EDRF), using endothelial cells in culture. Bovine pulmonary arterial endothelial cells (BPAE) were grown on microcarrier beads and superfused in a cell column. The effluent was applied to bioassay tissues and biological and the chemical characters of EDRF were examined and compared with those of nitric oxide (NO). EDRF was vascular selective and negatively charged, whereas NO was a general relaxant and not charged. The hypothesis that EDRF is identical to NO is discussed. We also examined the interaction of some EDRF agonists with endothelial cells and biological characteristics of the agonists were discussed.

Animals↗
PubMed1991

Statistical analysis of bilingual speaker's speech for cross-language voice conversion.

The goal of cross-language voice conversion is to preserve the speech characteristics of one speaker when that speaker's speech is translated and used to synthesize speech in another language. In this paper, two preliminary studies, i.e., a statistical analysis of spectrum differences in different languages and the first attempt at a cross-language voice conversion, are reported. Speech uttered by a bilingual speaker is analyzed to examine spectrum difference between English and Japanese. Experimental results are (1) the codebook size for mixed speech from English and Japanese should be almost twice the codebook size of either English or Japanese; (2) although many code vectors occurred in both English and Japanese, some have a tendency to predominate in one language or the other; (3) code vectors that predominantly occurred in English are contained in the phonemes /r/, /ae/, /f/, /s/, and code vectors that predominantly occurred in Japanese are contained in /i/, /u/, /N/; and (4) judged from listening tests, listeners cannot reliably indicate the distinction between English speech decoded by a Japanese codebook and English speech decoded by an English codebook. A voice conversion algorithm based on codebook mapping was applied to cross-language voice conversion, and its performance was somewhat less effective than for voice conversion in the same language.

Algorithms↗
PubMed1990

Detection of human papillomavirus (HPV) type 16 and 52b in cervical cancer tissues by Southern blot hybridization and polymerase chain reaction (PCR).

DNA samples from cancer tissues diagnosed histologically as squamous cell carcinoma of the uterine cervix were examined for the presence of human papillomavirus (HPV) genome DNA by Southern blot hybridization. Of 63 specimens, 32 were found to hybridize with HPV DNA probes; 23 specimens (35%) with HPV type 16 (HPV16), one (2%) with HPV type 18 (HPV18), four (7%) with HPV type 52b (HPV52b), and four others (7%) weakly with HPV52b. Specimens negative for HPV DNA with Southern blot hybridization were subjected to polymerase chain reaction (PCR) to determine the presence of HPV DNA under more sensitive conditions. After PCR using one set of primers specific for HPV16 and HPV52b, 7 out of 31 specimens were found to have HPV16 DNA. None was positive for HPV52b DNA. Our results indicate that HPV52b, as well as HPV16 and HPV18, is associated with squamous cell carcinoma of uterine cervix, and more sensitive determination of HPV infection can be made by amplification of the viral genome by PCR.

Base Sequence↗
PubMed1990

Detection of human papillomavirus DNA in genital condylomata in women and their male partners by using in situ hybridization with digoxygenin labeled probes.

Twelve couples (12 women and their male partners) presenting genital warts were investigated in order to evaluate the sexual transmission of human papillomavirus (HPV) in mutual partners and the localization of HPV DNA. Formalin-fixed, paraffin-embedded biopsy samples of 12 vulvar condylomata, and 12 penile condylomata from male partners were analyzed for the presence of HPV DNA-6, -11, and 16/18 by using in situ hybridization with digoxygenin labeled DNA probes. HPV DNA was identified in 9 women (75%) and in 9 men (75%). HPV-6 was frequently identified, being revealed in 42% of the vulvar specimens, in 67% of the cervical specimens and 58% of the penile specimens. Seven of 9 (77%) positive couples shared the same HPV DNA, and 2 couples harbored different HPV DNA types between the partners. The signal intensity of the HPV DNA was generally strong in superficial cell layers, weak in parabasal or basal cell layers. No malignant lesions resulted from the condyloma acuminatum caused by HPV-6 or -11. There were only mild dysplasia in the both sexes.

Condylomata Acuminata↗
PubMed1990

[Evaluation of aortocoronary bypass operation using a He-Ne laser flowmeter--comparison between internal mammary artery grafts and saphenous vein grafts].

It was very difficult to measure myocardial blood flow in clinical cases. Recently, a He-Ne laser doppler flowmeter was developed, and we made it possible to measure the pre-and post-operative myocardial blood flow in cases of coronary artery bypass grafting (CABG). We applied a laser flowmeter to 30 cases of bypass grafting to the left anterior descending coronary artery (18 cases with IMAG and 12 cases with SVG). The preoperative myocardial blood flow at the right ventricular anterior wall was 77 +/- 15 ml/min/100 gr, and the postoperative flow at the same point was 81 +/- 12 ml/min/100 gr. There was no significant change between the pre-operative value and the postoperative one. Myocardial blood flow at the left ventricular anterior wall in SVG group significantly increased from the preoperative value of 58 +/- 11 ml/min/100 gr to the postoperative value of 86 +/- 9 ml/min/100 gr (p less than 0.001). In IMAG group, myocardial blood flow at the left ventricular anterior wall similarly increased from 73 +/- 14 ml/min/100 gr to 83 +/- 15 ml/min/100 gr (p less than 0.01). The postoperative value of IMAG group was almost equal to the value of SVG group. The increased rate of myocardial blood flow at the left ventricular anterior wall was 52 +/- 32% in SVG group and 18 +/- 12% in IMAG group. These rates were obviously distinguished from the increased rate at the right ventricular anterior wall.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Preoperative diagnosis and surgical treatment of tricuspid regurgitation (TR) in patients with acquired valvular heart disease--comparison of Kay's annuloplasty and Carpentier's ring annuloplasty for tricuspid valve surgery].

The purpose of this study is to compare the results of TR repair by using doppler echocardiography. 52 patients who underwent tricuspid repair surgery from 1980 to 1987 were studied. 30 patients received Kay's annuloplasty (K-A group) while 16 patients were repaired with Carpentier's ring annuloplasty (C-E group). A new classification of TRs according to the direction and the area of the regurgitant flow on doppler echocardiogram was applied to the preoperative TRs. In addition to grading the severity of the regurgitations on a four-point scale, the TRs were subdivided into three types according to the direction of the regurgitant flow toward, the interatrial septum (type a), the center of the atrium (type b), and the lateral side of the right atrium (type c). Regurgitation covering more than two of the three areas was recognized as massive TR. In the K-A group, 5 cases showed massive TR and 11 cases showed localized TR preoperatively. Localized TR cases were well controlled in all cases but 4 out of 5 massive TR cases remained third grade and type b postoperatively. In the C-E group, 9 cases showed massive TR and 7 cases showed localized TR. All cases were displayed good control of the regurgitation postoperatively. Postoperative pressure half time of the tricuspid valve orifice treated with the two types of annuloplasty were 108 +/- 25 msec in the C-E group versus 151 +/- 43 msec in the K-A group (p less than 0.001), which indicates the tendency of the K-A group to produce narrowed tricuspid orifice.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Detection of human papillomavirus type 52b in cervical dysplastic tissue.

We examined infection in the tissue of cervical dysplasia of human papillomavirus (HPV) 52b, which we recently isolated from cervical cancer. To screen a lot of samples, we used an assay system with an HPV DNA typing kit containing an HPV 33 probe that cross-hybridizes with HPV 52b DNA. DNA samples from 123 patients with cervical dysplasia were first screened with this kit. Sixteen of these appeared to be positive, and they were subjected to Southern blot hybridization with the HPV 52b probe under highly stringent conditions. Of the 16 samples, two were found to have HPV 52b genome DNA. Our results, together with the fact that HPV 52b was isolated from cervical cancer, seem to support the notion that HPV 52b infection is closely associated with the onset of cervical cancer.

Blotting, Southern↗
PubMed1989

[Human papillomavirus DNA in vulvar lesions].

In order to study the role of human papillomavirus (HPV) in genital cancer, we attempt to determine the presence of HPV in tumors of the genital tract. In the current study, we have examined 35 histologically diagnosed cases of vulvar lesions in attempts to compare the sensitivities of various methods of detecting HPV. All but 7 vulvar lesions contained HPV DNA by Southern blot DNA hybridization. Detectability of HPV by immunocytochemistry and koilocytosis significantly declined as compared to DNA hybridization. The detection of HPV DNA by in situ hybridization is discussed.

Blotting, Southern↗
PubMed1989

[Surgical treatment of left ventricular aneurysm associated with mitral regurgitation].

The purpose of this study is to analyze the early and late results of left ventricular aneurysmectomy in patients with mitral regurgitation secondary to myocardial infarction. Twenty patients who had left ventricular aneurysm combined with mitral regurgitation underwent the isolated or combined aneurysmectomy during the last 10 years. There were 18 male cases and 2 female cases, and their age ranged from 31 to 64 (mean age 52.6 years). In 19 cases, the left ventricular aneurysm were caused secondary to antero-septal infarction due to the occlusion of the left anterior descending coronary artery. In one case, the coronary spasm of circumflex artery provoked the posterolateral myocardial infarction and the tendon rupture of posterior papillary muscle. The isolated left ventricular aneurysmectomy were performed in 6 cases and the combined operations were coronary artery bypass grafting in 11 cases, mitral annuloplasty in 1 case, mitral annuloplasty and bypass grafting in 1 case, and mitral replacement in 1 case. There were no operative death cases. The preoperative mean functional class (NYHA classification) was 2.9 and the postoperative class was 1.4. The preoperative mitral regurgitation of grade 1 in Sellers' classification was observed in 11 cases. Grade 2 regurgitation was observed in 6 cases, grade 3 in 2 and grade 4 in 1. After surgery, mitral regurgitation more than grade 2 was recognized in 3 cases (group A) and regurgitation less than grade 1 was seen in 17 cases (group B).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Ultrastructural observation of human papillomavirus particles in the uterine cervix intraepithelial neoplasia].

Using transmission electron microscopy (TEM), twenty two cases of an intraepithelial lesion in the uterine cervix have been examined for the presence of human papillomavirus (HPV) particles. In 21 of these cases (95%), HPV particles were detected in the nucleus, and in 5 cases, in the cytoplasm. The distribution of the intranuclear HPV particles was classified into 4 types. In only 2 cases did the exhibited particles show a geometrical crystalline array (type I). In most cases, the exhibited particles were either seen to show an aggregate non-crystalline array (type II) or were concentrated around the chromatin (type III). Some cases also were found to show particles that were scattered sporadically in the nucleoplasm (type IV).

Cytoplasm↗
PubMed1988

Comparative pharmacology of endothelium-derived relaxing factor and nitric oxide.

The present study was designed to characterize endothelium-derived relaxing factor (EDRF) and nitric oxide (NO) by employing both biological and chemical methods. EDRF was released by the calcium ionophore A23187 from cultured bovine pulmonary artery endothelium (BPAE) grown on microcarrier beads and then superfused in a cell column. The maximum relaxations induced by EDRF (83%) or NO (79%) on phenylephrine (PE)-contracted rabbit aorta were similar. In contrast, EDRF was only half as potent as NO in relaxing the KCl-contracted rabbit aorta. EDRF induced a concentration-dependent relaxation of both PE-contracted rabbit aorta and histamine-contracted guinea pig aorta that was accompanied by a marked elevation in cyclic GMP levels. However, EDRF was vascular selective and did not relax or increase cyclic GMP levels of the histamine-contracted taenia coli of either species. NO was not vascular selective and relaxed both aorta and taenia coli and also markedly increased cyclic GMP levels in each. NO also relaxed dog femoral artery and gastrointestinal smooth muscle preparation of the lower esophageal sphincter, whereas EDRF only relaxed the femoral artery. Experiments were also performed describing the actions of a series of different resins: anion exchange resins (NH2/NH, AG-1), cation exchange resin (-COOH), reversed phase resin (C18) and hemoglobin-agarose on EDRF- or NO-induced relaxation. NH2/NH, AG-1 and hemoglobin-agarose resins inhibited EDRF-induced relaxation, but -COOH and C18 did not. The inhibition was dependent on the amount of resin employed. NO-induced relaxation was blocked only by hemoglobin-agarose but by none of the other resins.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Characterization and function of bradykinin receptors in vascular endothelial cells.

One of many important roles of the naturally occurring nonapeptide bradykinin (BK) is the modulation of vascular tone. As endothelial cells may play vital roles in the physiology of vascular tissues, it is important to understand the interaction of this peptide with endothelial cells. By using radiolabeled BK we have demonstrated for the first time BK specific binding sites in membranes of bovine pulmonary artery endothelial cells. There are two types of receptors shown in binding assay: one with a saturable, high-affinity binding (Kd = 1.28 +/- 0.21 nM, maximum binding = 111.4 +/- 12.0 fmol/mg) and the other with not readily saturable, low-affinity binding. The activation of BK receptors on bovine pulmonary artery endothelial cells is assessed by two functional assays, namely, the release of endothelium-derived relaxing factor and the elevation of cytosolic calcium. The characteristics of the BK receptors in both binding and functional assays indicate that the high-affinity binding is to B2 receptors and the low-affinity binding is to B1 receptors on the cells. Thus, high-affinity binding is blocked by B2 antagonists, D-Arg[Hyp3, thienylalanine5,8,D-Phe7]-BK and [thienylalanine5,8, D-Phe7]-BK and low-affinity binding is blocked by B1 antagonist des-Arg9[Leu8]-BK. The elevation of intracellular calcium and the release of endothelium-derived relaxing factor in response to BK in endothelial cells is predominately through B2 receptor activation. The ability to subtype BK receptors in endothelial cells may facilitate the understanding of the vascular functions of BK and the potential design of drugs to regulate these functions.

Animals↗