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Biomedical subjects

Hiroyuki Ozaki

Publications and source records attributed to Hiroyuki Ozaki.

8 recordsLinked to original sources
PubMed2006

Structures of 17,19-hexatriacontadiyne monolayers on Au(111) studied by infrared reflection absorption spectroscopy and scanning tunneling microscopy.

The aggregation and reaction of 17,19-hexatriacontadiyne molecules are studied on a Au(111) surface. The molecular orientation and arrangement are elucidated by infrared reflection absorption spectroscopy (IRAS) and scanning tunneling microscopy (STM). A vapor-deposited monolayer and a multilayered film formed by adsorption from the solution provide IRA spectra with bands due to the antisymmetric and symmetric stretching of methylenes in the gauche conformation. After the adsorbed film is rinsed with the solvent, however, the spectrum loses the gauche bands and is characterized by the enhanced C-H(distal) and C-H(proximal) stretching bands, which means that all-trans molecules are laid flat. Only STM images for the rinsed film display columnar structures on the herringbones of the reconstructed Au(111) surface; the alkyl chain direction is found to be parallel to the Au atom row. The results indicate that an ordered monolayer is formed first at the liquid-solid interface, and then, disordered overlayers with the gauche conformation are grown but removed by a rinse. Upon exposure to UV light, thus obtained monomer columns are converted into oligomers with flexible backbones and an increased gauche population in the alkyl chains, which resemble red phase polydiacetylenes in LB films.

Journal Article↗
PubMed2006

Combined prognostic utility of ST segment in lead aVR and troponin T on admission in non-ST-segment elevation acute coronary syndromes.

Many studies have shown that ST-segment depression is a strong predictor of poor outcomes in patients with non-ST-segment elevation acute coronary syndromes (NSTE-ACSs); however, lead aVR was not considered in these studies. The present study examined the prognostic usefulness of the 12-lead electrocardiogram in combination with biochemical markers in 333 patients with NSTE-ACS. ST-segment deviation of > or =0.5 mm was considered clinically significant. Coronary angiography was performed a median of 3 days after admission in all patients. The primary end point was the composite of death, myocardial infarction, and urgent revascularization at 90 days. ST-segment elevation in lead aVR (odds ratio 13.8, 95% confidence interval 1.43 to 100.9, p = 0.03) and increased troponin T (odds ratio 7.9, 95% confidence interval 1.22 to 123.8, p = 0.04) were the only independent predictors of restricted events (death or myocardial infarction) at 90 days. ST-segment elevation in lead aVR (odds ratio 12.8, 95% confidence interval 4.80 to 33.9, p < 0.0001) and increased troponin T (odds ratio 2.03, 95% confidence interval 1.20 to 4.29, p = 0.04) were also the only independent predictors of adverse events (death, myocardial infarction, or urgent revascularization) at 90 days. When ST-segment status in lead aVR was combined with troponin T, patients with ST-segment elevation in lead aVR and increased troponin T had the highest rates of left main or 3-vessel coronary disease (62%) and 90-day adverse outcomes (47%). In conclusion, our findings suggest that ST-segment status in lead aVR combined with troponin T on admission is a simple and useful clinical tool for early risk stratification in patients with NSTE-ACS.

Aged↗
PubMed2006

Differences between men and women in terms of clinical features of ST-segment elevation acute myocardial infarction.

BACKGROUND: Many studies have examined sex-related differences in the clinical features of acute myocardial infarction (AMI). However, prospective studies are scant, and sex-related differences in symptoms of AMI remain unclear. We examined differences between men and women in terms of the clinical features of ST-segment elevation AMI. METHODS AND RESULTS: We studied 457 patients (106 women and 351 men) with ST-segment elevation AMI who were admitted within 24 h after symptom onset. The same cardiologist interviewed all patients within 48 h after admission. Women were older than men (72 vs 62 years, p<0.001) and had higher rates of hypertension (70 vs 56%, p=0.010), diabetes mellitus (36 vs 26%, p=0.047), and hyperlipidemia (51 vs 38%, p=0.019). Women were more likely than men to have non-specific symptoms (45 vs 34%, p=0.033), non-chest pain (pain in the jaw, throat, neck, shoulder, arm, hand, and back), mild pain (20 vs 7%, p<0.001), and nausea (49 vs 36%, p=0.013). On coronary angiography, the severity of coronary-artery lesions was similar in both sexes. In-hospital mortality was significantly higher in women than in men (6.6 vs 1.4%, p=0.003). CONCLUSIONS: Clinical profiles and presentations differ between women and men with AMI. Women have less typical symptoms of AMI than men.

Acute Disease↗
PubMed2006

Prognostic significance of inverted T waves in patients with acute pulmonary embolism.

BACKGROUND: The significance of inverted T waves remains unclear in patients with acute pulmonary embolism (PE). METHODS AND RESULTS: The relationship of the number of leads with inverted T waves to the severity of PE in 40 patients with acute PE was studied. Patients were classified into 3 groups according to the number of leads with inverted T waves on the admission electrocardiogram (ECG): 15 patients, or=7 leads (group H). In groups L, M and H, the rates of right ventricular dysfunction on echocardiography were 47%, 92% and 100% (p<0.01), respectively, and the rates of in-hospital complicated events (including death or the need for catecholamine support, cardiopulmonary resuscitation or mechanical cardiovascular support because of hemodynamic instability) were 0%, 8% and 46% (p=0.004), respectively. On multivariate analysis, arterial hypotension at presentation (odds ratio (OR) 8.96, p=0.049) and inverted T waves in >or=7 leads on the admission ECG (OR 16.8, p=0.037) were the only independent predictors of in-hospital complicated events. CONCLUSIONS: The number of leads with inverted T waves may be a useful and simple marker of increased risk for early complications in patients with acute PE.

Acute Disease↗
PubMed2006

Fluorescence resonance energy transfer-based assay for DNA-binding protein tagged by green fluorescent protein.

Specific interaction between green fluorescent protein (GFP)-tagged human alpha- or gamma-enolase(97-242) (alpha or gammaENO(97-242)) and the rhodamine-labeled DNA fragment containing the c-myc P2 promoter was detected by a fluorescence resonance energy transfer (FRET)-based assay, designated as a "real-time FRET assay." The approach of donor (GFP) and acceptor (rhodamine) was caused by the association between ENO(97-242) and the c-myc P2 promoter, and the time-dependent increase in fluorescence intensity of the reaction mixture was observed at ex=400 nm and em=590 nm. The relative affinity (R(as)) of ENO(97-242) mutants to the wild type was investigated with a real-time FRET assay, and it was clarified that the amino acids that participated in the interaction existed comparatively broadly. Although it was difficult to measure the absolute value of the affinity for the binding protein by using this method, it was possible to investigate the relative affinity of mutants for the wild type. A real-time FRET assay using the GFP-tagged protein could be used as not only a qualitative, but also as a quantitative analysis, this being the best for investigating the key amino acids in binding proteins.

DNA-Binding Proteins↗
PubMed2005

Predictors of left main or three-vessel disease in patients who have acute coronary syndromes with non-ST-segment elevation.

To identify an early, simple, noninvasive predictor of left main (LM) or 3-vessel disease (3-VD), we retrospectively studied clinical variables on admission in 310 patients with acute coronary syndromes with non-ST-segment elevation. Univariate analysis indicated that many factors were related to LM/3-VD. Multivariate analysis showed that ST-segment elevation in lead aVR of >/=0.5 mm was the strongest predictor of LM/3-VD, followed by positive troponin T (odds ratio 19.7, p <0.001, and odds ratio 3.08, p = 0.048, respectively). ST-segment elevation in lead aVR of >/=0.5 mm and positive troponin T identified LM/3-VD with sensitivities of 78% and 62%, specificities of 86% and 59%, positive predictive values of 57% and 26%, and negative predictive values of 95% and 87%, respectively (p <0.05). Our findings suggest that in patients with non-ST-segment elevation acute coronary syndromes, ST-segment elevation in lead aVR of >/=0.5 mm and positive troponin T on admission (especially the former) are useful predictors of LM/3-VD.

Adult↗
PubMed2004

Phase transition of a single sheet of sashlike polydiacetylene atomic sash on a solid surface.

The phase transition of sashlike polydiacetylene (PD) atomic sash in an extrathin (0.4 nm) vapor-deposited monolayer on a graphite (0001) surface has been observed by in-situ scanning tunneling microscopy (STM). The conformation of the atomic sash composed of a row of lying alkyl chains stitched up with a PD chain is different around the crossing points of the alkyl and PD chains in the two phases, and hence the contrast of the STM image is different in the middle of the sashes. The difference is associated with the color transition of bulk PDs.

Journal Article↗