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Biomedical subjects

K Takayanagi

Publications and source records attributed to K Takayanagi.

At least 19 recordsLinked to original sources
PubMed2000

Synthesis and characterization of helical multi-shell gold nanowires

Suspended gold nanowires were made in an ultra-high vacuum. The finest of them was 0.6 nanometer in diameter and 6 nanometers in length. By high-resolution electron microscopy, they were shown to have a multi-shell structure composed of coaxial tubes. Each tube consists of helical atom rows coiled round the wire axis. The difference between the numbers of atom rows in outer and inner shells is seven, resulting in magic shell-closing numbers.

Journal Article↗
PubMed2000

Air embolism in the right coronary artery occurring during the left coronary angioplasty using the guiding catheter with a side hole.

Coronary air embolism is one of the inadvertent complications of coronary angioplasty. We report two rare cases of complicating air embolism in the right coronary artery occurring during control left coronary angiography using a guiding catheter with a side hole, just prior to a coronary intervention procedure for a left coronary artery lesion. The air seemed to be injected into the right coronary artery through the side hole. When we use an angiographic or guiding catheter with a side hole, we should be aware that an air embolism can occur in the contralateral coronary artery and should carefully and repeatedly perform aspiration of the catheter.

Aged↗
PubMed2000

Comparison of the Ca2+ entry channels responsible for mechanical responses of guinea-pig aorta to noradrenaline and thapsigargin using SK&F 96365 and LOE 908.

Noradrenaline (NA) produces sustained contractions in conduit arteries such as aorta isolated from various animal species. In guinea-pig aorta, NA-produced sustained contraction is largely dependent upon the influx of extracellular Ca2+, but is refractory to the treatment with organic Ca2+ entry blockers. In the present study, we attempted to characterize pharmacologically the Ca2+ entry channel responsible for NA-produced sustained contraction of guinea-pig aorta using SK&F 96365 (1-[beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenylethyl]-1H-imi dazole) and LOE 908 ((R,S)-(3,4-dihydro-6,7-dimethoxy-isoquinoline-1-yl)-2-phenyl-N,N-di-[2- (2,3,4-trimethoxyphenyl)ethyl]-acetamide), both of which block voltage-independent Ca2+ channels. The effects of SK&F 96365 and LOE 908 on NA-produced contraction were compared with those on extracellular Ca2+-dependent contractile and endothelium-dependent relaxant responses to thapsigargin (TSG), an inhibitor of Ca2+-pump Ca2+-ATPase. NA (3x10(-6) M)-produced sustained contraction of guinea-pig aorta without endothelium exhibited a strong dependency on the extracellular Ca2+. Nicardipine (10(-7) M), diltiazem (10(-5) M) and verapamil (10(-5) M) did not show any appreciable inhibitory effects on NA-produced sustained contraction. SK&F 96365 concentration-dependently (10(-6)-10(-4) M) attenuated the NA-produced sustained contraction whereas LOE 908 did not affect it at concentrations up to 10(-4) M. Similarly, extracellular Ca2+-dependent contraction of guinea-pig aorta without endothelium in response to TSG was also diminished by SK&F 96365 but was unaffected by LOE 908. In fura-PE3-loaded vascular preparations, SK&F 96365 decreased both cytoplasmic Ca2+ level ([Ca2+]i) and muscle tension elevated by NA and TSG. Both SK&F 96365 and LOE 908 did not affect an endothelium-dependent relaxation of guinea-pig aorta in response to TSG. These findings suggest that in guinea-pig aortic smooth muscle cells, NA activates Ca2+ influx across the plasma-membrane through the Ca2+-permeable channel which is identical with or has similar properties to the store-operated Ca2+ channel (SOCC) stimulated by TSG, but is distinct from endothelial cell SOCC.

Acetamides↗
PubMed2000

Changes of the sacrum in severe spondylolisthesis: a possible key pathology of the disorder.

Deficient development of the posterior lumbosacral portion has been thought to be a possible etiology of severe spondylolisthesis. However, the precise causes of the deformity have yet to be revealed. To our knowledge, progression of the disorder has not been discussed in the light of sacral changes on magnetic resonance imaging (MRI). The objectives of the present study were to document changes of the sacrum on MRI scans in patients with severe spondylolisthesis and to discuss the relation of these changes to the progression of deformities. Roentgenograms and MRI scans of 13 patients (10 women and 3 men) with severe spondylolisthesis were retrospectively reviewed. Average age at first MRI examination was 20 years (range, 12 to 50 years). The MRI scans commonly showed a defect at the antero-superior portion of the sacrum. This lesion seems to appear during the period of progression of slipping associated with lumbosacral kyphosis. The defect of the sacrum was considered a unique feature to discriminate this type of olisthesis from others. Taking into consideration the present results, the deformity can be called kyphospondylolisthesis.

Adolescent↗
PubMed2000

Application of short tandem repeat of genomic DNA and mitochondrial DNA for identification of mixed-up tissue specimens.

Deoxyribonucleic acid (DNA) typing methods, short tandem repeat of genomic DNA and mitochondrial DNA with the use of polymerase chain reaction amplification, were applied to formalin-fixed, paraffin-embedded tissues submitted for diagnosis, to identify and sort out mixed-up tissue specimens. These techniques were found to be reliable, reproducible and specific for personal identification, and thus to eliminate the need for further examinations and to prevent unnecessary surgery.

Aged↗
PubMed2000

Insulin resistance affects endothelium-dependent acetylcholine-induced coronary artery response.

AIMS: This study was designed to investigate the relationship between insulin resistance and the acetylcholine-induced endothelium-dependent coronary artery response in patients without angiographically significant atherosclerotic coronary artery disease and to elucidate the pathophysiological significance of insulin resistance in the early stages of coronary atherosclerosis. METHODS AND RESULTS: Insulin resistance was calculated from fasting plasma glucose and insulin concentration using homeostasis model assessment in 40 patients suspected of having ischaemic heart disease, but without angiographic evidence of atherosclerotic coronary artery disease defined as a discrete stenosis or intimal irregularity. They were selected for an acetylcholine provocation test in both left and right coronary arteries. The homeostasis model assessment level was higher in 16 acetylcholine-positive patients than in 24 acetylcholine-negative patients (1.84+/-1.24 vs 0.72+/-0.62, P<0.01). Comparisons of the percentage change in vessel lumen diameter after the acetylcholine test in each of proximal, mid and distal segments of three coronary arteries among the three groups of low (less than 0.7; n=13), intermediate (0.7 to 1.4; n=13), and high homeostasis model assessment level (more than 1.4; n=14) revealed that a higher level resulted in a worse acetylcholine-induced constrictive response in coronary arteries. CONCLUSION: These results suggest that there is an association between high insulin resistance and coronary vascular endothelial cell dysfunction, and that insulin resistance may be an indicator of early stage coronary artery atherosclerosis not detectable by angiography.

Acetylcholine↗
PubMed2000

Idiopathic adrenal hemorrhage.

A case of idiopathic adrenal hemorrhage is reported. A 76-year-old woman exhibited a left adrenal tumor, 3 cm in diameter, on abdominal computed tomography. The patient was receiving aspirin medication for atrial fibrillation. There was no evidence of increased adrenal hormones. The mass enlarged to 6 cm in diameter within 18 months, and malignancy was suspected. The mass was diagnosed as adrenal hematoma by operative findings.

Adrenal Gland Diseases↗
PubMed2000

Direct discrimination and full-day disclosure of ventricular parasystole on new heart rate tachograms.

INTRODUCTION: To discriminate ventricular parasystole from fixed coupling interval ventricular premature complexes (VPCs), we developed a new diagnostic method using a dot distribution pattern corresponding to VPCs recorded on a heart rate tachogram using ambulatory ECG monitoring data. We tested our hypothesis that widely scattered VPC dots on instantaneous heart rate tachograms indicate a constant VPC-VPC interval compatible with parasystole. METHODS AND RESULTS: Patients with frequent VPCs > 5,000/day) were divided into two groups depending on the tachogram dot distribution patterns: group S (n = 10, aged 61 +/- 16 years) showed widely scattered VPC dot distribution, whereas group F (n = 10, 60 +/- 17 years) showed fixed VPC dot distribution limited to a narrow zone. Using digitized R-R interval data, full-day heart rate tachograms and VPC-VPC intervals were depicted simultaneously. Group S demonstrated constant basic VPC-VPC intervals (1,285 to 2,052 msec, mean 1,738 +/- 219), with a coefficient of variation (CV) of 0.061 +/- 0.018. Their VPC coupling intervals were markedly variable (651 +/- 113 msec; CV = 0.193 +/- 0.034). Each patient's basic VPC-VPC intervals showed small diurnal alterations (minimum -13% +/- 3% to maximum +15% +/- 6%). VPC-VPC intervals in group F were not constant and showed marked variation. Group F VPC coupling intervals were shorter and constant (480 +/- 30 msec, P = 0.0002; with CV = 0.076 +/- 0.013, P < 0.0001). CONCLUSION: Ventricular parasystole with constant VPC-VPC intervals consistently became evident based on VPC dot patterns recorded on heart rate tachograms.

Adolescent↗
PubMed2000

A preliminary study on the knowledge and attitudes of physicians at two university hospitals towards the medical insurance system of Japan.

In this preliminary study, we surveyed the physicians at two academic hospitals on their knowledge of and attitudes toward the medical insurance system in Japan. Most of the physicians had not read the "Ministerial Ordinance on Insurance Medical Institutions' and Insurance Medical Doctors' Medical Treatment under Health Insurance." Of the 433 physicians who filled out the questionnaire completely, 34% had either not read or rarely read the "Medical Fee Point List." Most (89.1%) of the physicians knew that there is a stepwise reduction in the hospitalization fee as the length of a patient's hospital stay increases. However, approximately 30% did not know the stipulation of obtaining an informed consent from the patient prior to blood transfusion. As for the right of patients to see their medical care remuneration statements, which was decided by the government in 1997, 26.8% of the physicians did not know this rule. Physicians who had read the "Ministerial Ordinance on Medical Treatment," were more likely to read the "Medical Fee Point List" frequently; were more likely to know the stipulation about diminishing hospitalization fee; were more likely to know that an informed consent must be obtained prior to blood transfusion; and were more likely to know that patients had a right to see their medical care remuneration statements. The longer the clinical experience of the physician, the more likely that the physician had read the "Ministerial Ordinance on Medical Treatment" and know the other stipulations well. In these two academic hospitals, it is important to establish educational seminars for physicians on the guidelines of the medical insurance system so that physicians will become familiar with the medical insurance system quickly.

Attitude of Health Personnel↗
PubMed2000

[Does disclosure of medical records to patients influence medical care?].

UNLABELLED: Disclosure of medical records to patients has been assessed, but the influence of disclosure on medical care has not been well researched. To address this situation, this study was conducted to test three hypotheses: 1) doctors think that the disclosure can influence medical care, 2) whether doctors think disclosure can influence medical care depends on how they rank medical records (for example, as evidence for diagnosis and treatment, a process to reach a diagnosis, a tool to communicate with other medical staff, etc), and on whether they think medical record disclosure could change the content of the record. Questionnaires were sent to 881 doctors who work at two hospitals affiliated with N Medical School and K Medical University. RESULTS: Four hundred eighty-eight doctors responded. The findings related to the hypotheses were as follows: 1) Those who answered that the disclosure could have an influence on medical care were 49.1% of the total. 2) There was no relation between how doctors ranked medical records and whether they thought disclosure could influence medical care. 3) Doctors who answered that there were things that they would not be able to write if medical records were disclosed accounted for 73.5% of the total. These doctors answered "yes" significantly higher to the question that the disclosure could influence medical care than others (Odds 3.6, P < 0.01). Doctors who thought they would not be able to enter the diagnosis, the name of the disease for insurance, self-evaluation, information that could be judged and subjective information answered that disclosure could influence on medical care (P < 0.05). It was assumed that disclosure of medical records to patients could change the content of the medical records and that could influence medical care. How to deal with information will become an important issue if records are disclosed.

Attitude of Health Personnel↗
PubMed2000

Reflex sympathetic dystrophy following transbrachial cardiac catheterization.

We experienced a rare case of complication by reflex sympathetic dystrophy (RSD) following transbrachial cardiac catheterization which may have been caused by poorly executed hemostasis using a hemostatic device. The symptoms of RSD markedly limited the patientOs daily work activities. Although the transbrachial approach is a useful procedure for cardiac catheterization, interventionalists should be aware that RSD may cause serious complications.

Aged↗
PubMed1999

Colony stimulating factor-inducing activity of hesperidin.

To evaluate immunomodulating activities of bioflavones, colony-stimulating factor (CSF)-inducing activity of two dihydroflavones, three flavones and three flavonols were tested. These samples were suspended in saline and injected intraperitoneally (i.p.) into mice at a dose of 1 mg 6 h before bleeding. All compounds carrying the glucosyl-rhamnose moiety showed potent activity. Among them, hesperidin exhibited the strongest activity. Serum CSF production in mice injected with 1 mg hesperidin reached a peak at 9 h later. The activity of hesperidin was dose-dependent at a range of 0.3 to 20 mg/mouse.

Adjuvants, Immunologic↗
PubMed1999

Serum levels of circulating adhesion molecules after coronary angioplasty.

The activation of platelets, leukocytes, and vascular endothelial cells mediated by cell adhesion molecules may play a role in the mechanism of restenosis, which is still a significant complication after coronary angioplasty. We observed serial changes in the circulating soluble forms of adhesion molecules in 25 patients with coronary artery disease who underwent coronary angioplasty for a single lesion of the left anterior descending artery. Serum levels of sICAM-1 (p < 0.05) and sP-selectin (p < 0.05) were significantly increased immediately after angioplasty in the coronary sinus blood samples. These increases continued during the 48-hour observation period, and the maximum increase was seen 48 h after angioplasty for sICAM-1 (p < 0.01) and 24 h after angioplasty for sP-selectin (p < 0. 01). The level of sL-selectin increased 24 h (p < 0.01) and 48 h (p < 0.001) after angioplasty. These changes were not observed in the peripheral blood samples. The sE-selectin level did not change after angioplasty. A multiple regression analysis showed that the late loss index obtained from quantitative angiographic (QCA) analysis was correlated with the changes in sICAM-1 (r = 0.31, p < 0.05), sL-selectin (r = 0.28, p < 0.05), and sP-selectin (r = 0.26, p < 0. 05) 48 h after angioplasty in the coronary sinus blood samples, but was not correlated with procedural variables, other QCA variables, or the change in the sL-selectin level. The measurements of these adhesion molecule levels may help to evaluate traumatic vessel wall injury and inflammation at the intervention site after coronary angioplasty.

Analysis of Variance↗
PubMed1999

[Research on the influences that affect the physician's perception of discharge summaries. A survey of outpatient department physicians].

The object of this study was to improve the completion of discharge summaries. The purpose of this article is: 1. to describe the perceptions of outpatient department physicians as to whether incomplete discharge summaries affect outpatient medical care or not, and 2. to elucidate the factors contributing to their perceptions. The physicians were randomly selected from among "the National Certified Training Hospitals" and "Japan Society for Quality in Health Care", and the size of the hospitals, the medical record management system and the format of the discharge summary were chosen for analysis of the factors that affect physicians' perceptions. Of the 2,304 questionnaires sent, 935 (40.6%) were returned. The results showed that 832 (89.0%) of the physicians thought that outpatient medical care would be affected if discharge summaries were not completed. Based on the analysis of the factors affecting the perceptions of the physicians, there was a trend showing that the influence was lower in small hospitals (p < 0.05), that the centralized management system for medical records had a higher influence (p < 0.05), and that the format of the discharge summary also affects physician's perceptions (p < 0.05).

Ambulatory Care↗
PubMed1999

Cyclic bursts of ventricular premature contractions of more than one minute intervals.

Ventricular premature contractions (VPCs) occasionally appear successively in the form of bigeminy, trigeminy or quadrigeminy associated with quiescent periods. However, details of these rhythmic VPC bursts have not been well documented. We analyzed the incidence, periodicity and interval of VPC bursts exhibiting bigeminy or trigeminy using ambulatory ECG monitoring and computer analysis. We defined VPC bursts as more than 5 successive groups of VPCs each containing more than 20 VPCs in the form of bigeminy or trigeminy that were interrupted by normal sinus rhythm lasting for more than 60 seconds. Bursts thus defined were observed transiently or continuously in 78 out of 500 consecutive patients showing > 3000 VPCs a day. Their age ranged from 14 to 76 years (mean 48). Forty patients were men and 38 were women. We could discriminate between two types of bursts on the instantaneous heart rate tachograms. Dome type bursts (n = 48) showed gradual shortening of the VPC coupling intervals whereas horizontal type bursts (n = 30) demonstrated fixed coupling intervals during the bursts. Cycle length of the dome type burst was 185 +/- 40 seconds and regular, whereas it was 210 +/- 63 seconds and irregular in the horizontal type (NS). Duration of the VPC bursts was 101 +/- 31 seconds in the dome type and 98 +/- 41 seconds in the horizontal type. Both burst types were associated with transient increases in sinus rate and abbreviated VPC-VPC intervals. We suspect ventricular parasystole to be the mechanism of these bursts especially in the dome type. Recognition of these two burst types from heart rate tachograms may be of value in the suppression of VPCs.

Adolescent↗
PubMed1999

[Evaluation of restenosis after percutaneous transluminal coronary angioplasty using a Doppler index, the Tei index].

Cardiac function and restenosis were evaluated after percutaneous transluminal coronary angioplasty (PTCA) using a Doppler index (the Tei index). Thirty-eight patients, 31 men and 7 women (mean age 57 years) with ischemic heart disease were studied. The underlying heart diseases were angina pectoris without left ventricular asynergy in 16 patients and old myocardial infarction (OMI) with left ventricular asynergy in 22 . Ejection fraction was measured by M-mode echocardiography and deceleration time, and the interval between cessation and onset of the mitral inflow velocity (a), ejection time at aortic valve (b), and the Tei index [(a-b)/b] were measured by M-mode echocardiography performed before and 6 months after PTCA. The ejection fraction, deceleration time and Tei index showed no changes after PTCA in patients with angina pectoris with or without restenosis. In patients with OMI with restenosis, the Tei index increased slightly after PTCA, from 0.56 +/- 0.15 to 0.61 +/- 0.13. The deceleration time changed from 0.23 +/- 0.03 to 0.24 +/- 0.02 msec, and the ejection fraction from 0.46 +/- 0.11 to 0.51 +/- 0.17, neither significantly. However, in patients with OMI without restenosis (15 out of 22 patients), the Tei index significantly improved after PTCA, from 0.55 +/- 0.13 to 0.48 +/- 0.12 (p < 0.05). In patients with left ventricular asynergy due to old myocardial infarction, without restenosis, the Tei index significantly improved after PTCA. The Tei index is useful for evaluating restenosis after PTCA in patients with OMI.

Angina Pectoris↗
PubMed1998

cDNA cloning, expression, and characterization of the human bifunctional ATP sulfurylase/adenosine 5'-phosphosulfate kinase enzyme.

A cDNA encoding the human bifunctional ATP sulfurylase/adenosine 5'-phosphosulfate (APS) kinase was cloned and sequenced. The enzyme contains an APS kinase domain in its N-terminal portion and an ATP sulfurylase domain in its C-terminal portion. Recombinant full-length enzyme and its constituent APS kinase and ATP sulfurylase domains were individually expressed, purified, and shown to have their respective enzymatic activities.

Amino Acid Sequence↗