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Dive into the research topics where Yukihisa Miyazawa is active.

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Featured researches published by Yukihisa Miyazawa.


Life Sciences | 2000

Comparison of the effects of zolpidem and zopiclone on nocturnal sleep and sleep latency in the morning: A cross-over study in healthy young volunteers

Toru Nakajima; Tsukasa Sasaki; M.D. Kazuyuki Nakagome; Satoru Takazawa; M.D. Emi Ikebuchi; M.D. Yutaka Ito; Yukihisa Miyazawa; Masatoshi Tanaka; Osamu Kanno

Zolpidem (ZOL) and zopiclone (ZPC) are non-benzodiazepine hypnotics, with unique effects on sleep architecture compared with conventional benzodiazepines. The two compounds have different profiles in action to two major subtypes of the GABA-A receptors, therefore different effects on sleep structure may be expected. In the present study, the effects of ZOL (10mg) and ZPC (7.5mg) were compared in nine healthy young male subjects during nine-night sessions, employing a crossover design. Time courses during the sessions were significantly different between the compounds in the ratio (%) of S2 and S1. Compared to the baseline, an increase of S2 and a decrease of S1 and SR were caused by ZPC, not by ZOL. SWS was increased by both ZPC and ZOL. Significant changes by ZOL were found during the first 150-min, while changes by ZPC were mostly observed during the second 150-min. This might be related to their half-lives. ZOL did not affect sleep latency in the morning, while ZPC caused a significant decrease. Subjective sleepiness, however, was not increased in the ZPC or ZOL mornings. It was speculated that difference in the action to the GABA-A receptor subtypes might be related to the differences in the effects on the sleep architecture between the compounds.


Atherosclerosis | 2014

Validation of homogeneous assays for HDL-cholesterol using fresh samples from healthy and diseased subjects

Takashi Miida; Kunihiro Nishimura; Tomonori Okamura; Satoshi Hirayama; Hirotoshi Ohmura; Hiroshi Yoshida; Yoh Miyashita; Masumi Ai; Akira Tanaka; Hiroyuki Sumino; Masami Murakami; Ikuo Inoue; Yuzo Kayamori; Masakazu Nakamura; Tsutomu Nobori; Yukihisa Miyazawa; Tamio Teramoto; Shinji Yokoyama

BACKGROUND High-density lipoprotein-cholesterol (HDL-C) is a negative risk factor for cardiovascular events. Although several homogeneous HDL-C assays are available, their accuracy has not been validated, particularly in subjects with disease. We aimed to clarify whether HDL-C concentrations measured by homogeneous assays [HDL-C (H)] agree with those determined by the reference measurement procedures [HDL-C (RMP)] using ultracentrifugation and precipitation with heparin-manganese reagent in fresh clinical samples. METHODS HDL-C concentrations in samples from 48 healthy subjects and 119 subjects with disease were determined using 12 homogeneous assays and RMPs. RESULTS All reagents showed excellent intra- and inter-assay CVs (<2.23%) for two pooled sera. Furthermore, the mean bias was within ± 1.0% in nine reagents using samples from healthy subjects and in eight reagents using samples from subjects with disease. In a single HDL-C (H) determination, the total error requirement of the National Cholesterol Education Program (95% of results < 13%) was fulfilled in nine reagents using samples from healthy subjects and six reagents in those from subjects with disease. Error component analysis revealed that only one reagent exceeded ± 10% total error in samples from healthy subjects, whereas four reagents exceeded this error in samples from subjects with disease. Correlations between HDL-C (H) and HDL-C (RMP) revealed that the slopes were within 1.00 ± 0.06 in six reagents in healthy subjects, and eight reagents in subjects with disease. CONCLUSIONS Except for three reagents, HDL-C (H) agrees well with HDL-C (RMP) in subjects with common disease, but not in those with extremely low HDL-C or abnormal HDL composition.


Virus Genes | 2000

Differential effect of TPA on cell growth and Epstein-Barr virus reactivation in epithelial cell lines derived from gastric tissues and B cell line Raji.

Mikiko Kanamori; Masako Tajima; Yukio Satoh; Yoshiko Hoshikawa; Yukihisa Miyazawa; Kota Okinaga; Takeshi Kurata; Takeshi Sairenji

We characterized the cell growth and Epstein-Barr virus (EBV) reactivation for EBV infected epithelial cell lines, GT38, GT39, and GTC-4 using 12-O-tetradecanoylphorbol-13-acetate (TPA). These cell lines grew similarly in liquid medium, and formed colonies in soft agar. The cell growth was inhibited with TPA, dose-dependently in liquid medium. The colony formation was enhanced with low concentrations of TPA, but was inhibited with high concentrations. The latent EBV was reactivated with high concentrations of TPA as shown by the expression of EBV BZLF1 gene product ZEBRA. The effects of TPA on GTC-4 were compared with a Burkitts lymphoma cell line Raji. The mode of actions of TPA in GTC-4 was different from Raji in terms of cell growth and EBV reactivation. The effective concentrations of TPA for cell growth inhibition and EBV reactivation were higher in Raji than GTC-4. Cell cycle analysis showed that TPA (20 ng/ml) induced cell cycle arrest to Raji but not to GTC-4; however, the rate of trypan blue stained cells increased in the TPA treated GTC-4 but not Raji. These results demonstrated that TPA affects differentially for the stimulation and inhibition of cell growth, and also EBV reactivation depends on TPA concentrations and cell types.


Surgery Today | 2000

Emergency Abdominal Surgery in Patients Aged 80 Years and Older

Katsunori Nishida; Kota Okinaga; Yukihisa Miyazawa; Keita Suzuki; Masanao Tanaka; Minoru Hatano; Atsushi Hirose; Miki Adachi

Abstract: The outcome of emergency abdominal surgery in elderly patients remains unsatisfactory. We studied factors contributing to the outcome of abdominal emergency surgery in elderly patients, particularly in those aged 80 years and older. Subjects were 61 patients aged 80 years and older (group A) and 108 patients aged from 65 to 79 years (group B) who underwent emergency abdominal surgery between 1983 and 1997. Complications were significantly higher in group A than in group B, with respiratory failure the most common postoperative complication. Mortality rate within 30 days after surgery was also higher in group A (9.8%) than in group B (3.3%). Complications and mortality did not differ significantly between those with and without preexisting concomitant disease in group A. Systemic inflammatory response syndrome (SIRS) was seen in 35 patients in group A and 50 in group B. Severe complications occurred in 62.5% of group A with preoperative SIRS. Mortality in those with SIRS was significantly higher than those without. SIRS is thus a feasible predictor of poor outcome in patients aged 80 years and older who have emergency abdominal surgery and in those aged from 65 to 79 years. Patients with SIRS should initially receive minimal treatment whenever possible, rather than be overtreated, until their conditions stabilize.


Surgery Today | 1991

Primary venous aneurysm of the forearm in a child

Katsunori Nishida; Yukihisa Miyazawa; Kaoru Matsumoto; Kota Okinaga; Tesuo Imamura

A 5 year old girl who presented with two bluish, cystic masses in her right forearm was shown on ultrasonography to have two localized saccular dilatations of the right radial vein. This led to the suspicion of venous aneurysms which was later confirmed by venography. They were finally excised because of the gradual increase in size and pain she had experienced over the previous two months.


Pediatrics International | 1997

Fatty acid compositions of colostrum, cord blood, maternal blood and major infant formulas in Japan

Chainllie Young; Toshiyuki Hikita; Sono Kaneko; Yukiko Shimizu; Satoko Hanaka; Toshiaki Abe; Hiroyuki Shimasaki; Ritsuko Ikeda; Yukihisa Miyazawa; Akira Nakajima

Lipid profiles in colostrum, cord blood, maternal blood and major infant formulas in Japan were analyzed. In the first part of the study, colostrum obtained from 36 normal delivery women and six kinds of infant formulas provided by three major milk companies were analyzed for their fatty acid composition using capillary gas‐lipid chromatography. Although enriched with docosahexaenoic acid (DHA), the percent composition of DHA in the six infant formulas (0.15–0.21%) was significantly lower than that in the colostrum (1.1 ± 0.54). Arachidonic acid (AA) and eicosapentaenoic acid (EPA) were present in the colostrum but not detectable in the infant formulas. It is recommended that although the exact amount of specific fatty acids needed in the infant diet was not completely known, to be as close as possible to natural breast milk, the level of DHA, EPA and AA should be raised in the infant formulas. In the second part of the study, 19 pairs of maternal and cord blood were analyzed for their lipid profile. All samples were from normal vaginal delivery. The measurement of cholesterol, triglycerides, phospholipids and free fatty acids was performed with commercially available enzymatic methods on an automated discrete random access analyzer. Total fatty acid was determined as described in the first part of the study. The results were analyzed with Spearmans rank correlation coefficient. No correlation could be found between maternal and fetal concentrations of cholesterol, triglycerides, phospholipids or total fatty acids. Correlation could be found in non‐esterified fatty acids, in palmitic acids, and oleic acid levels. It was concluded that the lipid transport and metabolism in the fetal‐placenta unit is complex and further delicate investigation is required.


Journal of Cardiology | 2009

Screening method for severe sleep-disordered breathing in hypertensive patients without daytime sleepiness.

Taiji Furukawa; Masaaki Suzuki; Ikuko Funatogawa; Takaaki Isshiki; Yukihisa Miyazawa; Tamio Teramoto; Eiji Yano

The high prevalence of sleep-disordered breathing (SDB) in hypertensive patients has been well studied. However, regular screening of SDB in these patients is not performed routinely as the diagnostic procedures are both time-consuming and labour-intensive. Overnight portable device screening is useful, but is sometimes not acceptable for asymptomatic SDB patients. We evaluated the usefulness of daytime 30-min recording with a portable recording device during pulse wave velocity (PWV) measurement sessions as a screening method for detection of asymptomatic SDB in hypertensive patients. Eighty-one hypertensive patients underwent 30-min daytime screening session using a Type III portable recording device during PWV measurement. Each screening session was followed by full overnight Level I polysomnography (PSG). The screening session included recordings of airflow (mouth-nose), chest movement, oximetry, and electrocardiography. The correlation coefficient between respiratory disturbance index (RDI) by screening session and apnea-hypopnea index (AHI) by PSG was 0.64. Using AHI ≥ 30 as diagnostic of severe SDB, 47 of 80 patients had the disorder based on PSG results. Using an RDI cut-off value of 22, the sensitivity and specificity for detection of severe SDB were 86.1% and 64.5%, respectively. Daytime 30-min recording with a portable device for apnea detection during PWV recording is useful for screening of asymptomatic severe SDB in hypertensive patients.


Journal of Infection and Chemotherapy | 2011

The usefulness of changing focus during examination using Gram staining as initial diagnostic clue for infective tuberculosis

Yoshiko Atsukawa; Sayoko Kawakami; Miwa Asahara; Shinobu Ishigaki; Takashi Tanaka; Yasuo Ono; Hajime Nishiya; Ryuichi Fujisaki; Ichiro Koga; Yasuo Ota; Yukihisa Miyazawa

Gram staining is a useful technique for detecting bacteria but is highly questionable in detecting Mycobacterium tuberculosis. Its detection generally requires special staining, such as Ziehl–Neelsen staining. We experienced three cases in which tuberculosis was first suggested by Gram staining of sputum or pus, confirmed by Ziehl–Neelsen staining, and diagnosed by polymerase chain reaction or culture. To find colorless tubercle bacilli in clinical samples with various organisms, varying the focus to slightly longer and shorter during study of the slides is indispensable. We present criteria for detecting infective pulmonary tuberculosis in Gram staining. First, in the ordinary focus, weakly stained, thin, gram-positive bacilli are found; second, with a slightly longer focus distance, the thin, cord-like, conspicuous gram-positive bacilli can be observed; and third, with a shorter focus distance, the gram-positive bacilli have changed into the brightened, colorless, or ghost ones. Four laboratory technologists each evaluated 20 Gram-stained samples after being lectured on the criteria, with no prior information about the sample. They accurately evaluated the presence of the bacilli in Gram-stained preparations in more than 90% of samples containing 3+ bacilli on Ziehl–Neelsen staining. Gram staining is available as an easy and rapid initial clue to recognize highly infective tuberculosis.


Microbes and Infection | 2001

Spontaneous reduction in Epstein-Barr virus (EBV) DNA copy number in EBV-infected epithelial cell lines.

Mikiko Kanamori; Masanao Murakami; Tomoko Takahashi; Nanao Kamada; Masako Tajima; Kota Okinaga; Yukihisa Miyazawa; Takeshi Kurata; Takeshi Sairenji

We found that spontaneous and 12-0-tetradecanoylphorbol-13-acetate-induced Epstein-Barr virus (EBV) reactivation occurred in short-term (ST)-cultured EBV-infected epithelial cell lines GT38 and GT39 after their establishment; however, it diminished in the long-term (LT)-cultured cells passaged for more than 2 years from ST-cultured cells. We hypothesized that the EBV reactivation may be related to the EBV DNA copy number in the cells. A higher level of EBV DNA content was detected in ST-cultured cells than in LT-cultured cells by Southern hybridization using an EBV DNA XhoI probe. Fluorescence in situ hybridization using EBV DNA BamHI W fragments showed that ST-cultured cells contained a higher EBV DNA copy number than that of LT-cultured cells. EBV DNA-negative cells were detected in small proportions in LT-cultured cells, but were undetected in ST-cultured cells. These results demonstrate that EBV genomes are not maintained stably in the cell lines, and some of them are lost in continuous passages of the cells. We discuss the mechanisms of reduction of EBV reactivation and EBV DNA in the cell lines.


Current Topics in Microbiology and Immunology | 2001

Characterization of EBV-infected epithelial cell lines from gastric cancer-bearing tissues.

Takeshi Sairenji; Masako Tajima; M. Kanamori; Noriko Takasaka; X. Gao; Masanao Murakami; Kota Okinaga; Yukio Satoh; Yoshiko Hoshikawa; Hisao Ito; Yukihisa Miyazawa; Takeshi Kurata

The long-term goal of our study is to explore how Epstein-Barr virus (EBV) associates with the pathogenesis of gastric carcinoma. The first goal is to establish EBV-positive epithelial cell lines from EBV-infected gastric carcinoma tissues and to characterize the cell lines and EBV infection in the cells. EBV, a ubiquitous human herpesvirus with oncogenic potential, is predominantly associated with the infection of two target tissues in vivo: (1) B lymphocytes, where the infection is largely nonproductive, and (2) the epithelium, in which virus replication occurs (Rickinson and Kieff 1996). Both target tissues are susceptible to EBV-associated malignant change, leading to tumors of B-cell origin, such as Burkitt’s lym-phoma, or of epithelial-cell origin, such as nasopharyngeal carcinoma (NPC) (Pathmanathan et al. 1995). Recently, EBV has also emerged as an etiologic agent implicated in gastric carcinoma (Min et al. 1991; Shibata et al. 1991; Shibata and Weiss 1992; Tokunaga et al. 1993a,b; Fukayama et al. 1994; Imai et al. 1994; Ohfuji et al. 1996; Iwasaki et al. 1998). EBV has been found in most cases of rare gastric lymphoepithelioma-like carcinomas (Min et al. 1991; Shibata et al. 1991; Ohfuji et al. 1996) and a small but significant proportion of common gastric adenocarcinomas (Shibata and Weiss 1992; Tokunaga et al. 1993a,b). EBV infection was found in approximately 7% of Japanese gastric carcinomas (Tokunaga et al. 1993a,b; Fukayama et al. 1994; Imai et al. 1994). The world distribution of gastric carcinomas with EBV infection is shown from 4% to 18% of total gastric carcinoma in different countries (Tashiro et al. 1998)

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