Biomedical subjects

Hiroki Sugihara

Publications and source records attributed to Hiroki Sugihara.

44 records · Page 3Linked to original sources

PubMed2002

Response of MSTd neurons to simulated 3D orientation of rotating planes.

We studied whether the dorsal division of the medial superior temporal area (MSTd) in the macaque has activity related to structure-from-motion (SFM) processing. As the simplest form of three-dimensional (3D) structure, we chose a planar stimulus and examined the relation between the neural responses and the simulated 3D orientation of the plane defined by motion cues. We recorded from 114 MSTd neurons while monkeys were performing a visual fixation task. These neurons responded to a basic set of optic flow patterns such as translation, expansion/contraction, and rotation. Responses of these neurons to rotating plane stimuli were examined to see whether the MSTd neurons exhibited selectivity to the tilt and slant that characterize the 3D orientation of the plane. We found that most MSTd neurons tested (97 of 114) responded to the plane stimuli, and many neurons (65 of 97) exhibited selectivity to tilt and/or slant. Of 97 neurons, 18% (17/97) were selective only to tilt, 24% (23/97) only to slant, and 26% (25/97) to both. Control experiments rejected the possibility that the selectivity could be explained solely by the sensitivity to local stimulus components such as local translation, local speed, and local speed gradients. These results suggest that MSTd neurons are sensitive to stimulus features specific to the perceived 3D orientation of the rotating plane stimuli and suggest that area MSTd is involved in SFM processing.

Animals↗

PubMed2002

Surgical removal of intra-aortic balloon catheter with fractured nitinol central lumen: a case report.

A 73-year-old woman suffering from septic shock was given circulatory assistance by intra-aortic balloon pumping (IABP). Eleven hours later, pumping stopped abruptly and blood reflux was observed in the intra-aortic balloon catheter (IABC). We removed it and inserted another IABC; 3.5 h later, pumping stopped again and blood reflux was seen. Removal of the IABC was attempted, as the systolic aortic pressure remained above 100 mmHg, but there was resistance during the removal and as a result 7.5cm of the catheter from the tip remained inside the vessel. Fluoroscopy indicated that the metal tube that formed the central lumen in the balloon was fractured, and that its edge had perforated the femoral artery. The balloon was then removed surgically. Fracture of the metal tube and balloon perforation were confirmed in both the damaged IABCs. Postoperative computed tomography and magnetic resonance imaging indicated a highly severe posterior-anterior bend in the patient's aorta. A vessel model similar to the aorta in this case was made and a reproducibility test was conducted; the central lumen fractured within 3 h and under a microscope the profile of the fractured test lumen was similar to the one in the clinical case. These findings suggest that placing a pumping IABC in a bending aorta causes fracture of the central lumen from fatigue failure because the central lumen is under excessive stress.

Aged↗

PubMed2002

Electrocardiographic score as a predictor of mortality after subarachnoid hemorrhage.

Electrocardiographic (ECG) changes are often associated with subarachnoid hemorrhage (SAH), but it is not well known whether these have prognostic value. The present study retrospectively investigated 122 consecutive patients with SAH caused by ruptured aneurysms. The patients were classified based on the in-hospital outcome into 80 survivors and 42 nonsurvivors. In nonsurvivors, abnormalities often observed on the 12-lead ECG on arrival at hospital were abnormal Q wave, ST depression, and T wave inversion. The ECG score was defined as the total number of leads that had any of these 3 ECG abnormalities. Univariate analysis revealed a strong correlation of in-hospital death with the ECG score, the neurological status estimated by the grading of Hunt and Kosnik, age, and QTc interval. In age- and sex-adjusted multiple logistic regression analysis, the ECG score was the most powerful risk stratifier (ECG score > or = 6 vs ECG score < 6; p=0.0026, odds ratio 14.39, 95% confidence interval 2.54-81.71). The ECG score, a new and simple method of semi-quantification, was a powerful risk predictor in the present patients with SAH.

Aged↗

PubMed2002

[Chronic pulmonary thromboembolism originating from left forearm deep vein thrombosis: a case report].

Upper extremity deep venous thromboembolism has become increasingly common due to the use of subclavian venous access. However, forearm deep venous thrombosis is rare. We report a case of chronic pulmonary thromboembolism originating from left forearm deep venous thrombosis. A 66-year-old woman was admitted to our hospital because of dyspnea, which had worsened over the previous 2 months. Echocardiography showed severe right ventricular enlargement and pulmonary hypertension. Perfusion lung scintigraphy revealed multisegmental perfusion defects. No likely factors responsible for hypercoagulability were found. The patient had a history of left radial fracture and had been treated with external fixation. Venography of the upper and lower extremities revealed total occlusion of the deep veins of the left forearm with collateral vessels, but no evidence of other upper or lower extremity venous thrombosis.

Aged↗

PubMed2002

[Serial change of myocardial fatty acid metabolism in a case with severe myocardial ischemia].

A 66-year-old-man was admitted to our hospital because of chest pain on effort in October 1999. The initial images of 123I-BMIPP myocardial SPECT (BM) showed moderately decreased tracer uptake in the apex and the delayed images revealed redistribution in the apex. Coronary angiography revealed 99% stenosis in the proximal portion of the left anterior descending artery. Since sudden onset anaphylactic shock induced by contrast media developed, so percutaneous transluminal coronary angioplasty was not performed. The patient's symptoms were improved with medical treatment. On BM in March 2000, the initial images indicated slightly reduced uptake in the apico-anteroseptal region and the delayed images revealed mildly redistribution in the same area. BM in September 2000, the initial images showed moderately reduced uptake in the apico-anteroseptal region and the delayed images revealed high washout in the same area. The patient's symptoms markedly deferiorrated in March 2001, and BM initial images revealed slightly reduced uptake in the apico-anteroseptal region and the delayed images revealed redistribution in the same area again. During the clinical course, electrocardiography and 99mTc-tetrofosmin myocardial SPECT revealed no marked changes. We consider that 123I-BMIPP myocardial SPECT is useful in estimating myocardial ischemia.

Aged↗

PubMed2002

[A case of "Takotsubo" cardiomyopathy observed with myocardial scintigraphy from the acute phase].

A 57-year-old woman was emergently admitted to our hospital because of chest oppression. On examination, blood pressure was 174/96 mmHg, pulse rate was 90/min and coarse crackle and third heart sound were audible. On laboratory data, the levels of LDH and CPK-MB were mildly elevated. Electrocardiogram (ECG) demonstrated elevation of the ST segment in leads I, aVL and V2-V5. 99mTc-tetrofosmin myocardial SPECT (TF) showed severely reduced uptake in the apex and anterior wall. Emergent coronary angiography (CAG) did not show any stenotic lesion. Left ventriculography (LVG), however, demonstrated akinesis of the apex, anterior, and inferior walls, and basal hyperkinesis. On the second hospital day, ECG demonstrated inverted T wave in leads I, aVL and V2-V5. 123I-BMIPP myocardial SPECT (BMIPP) and 123I-MIBG myocardial SPECT (MIBG) were performed on the second and fourth hospital days, respectively. These cardiac images showed severely reduced uptake equally. TF, BMIPP, and MIBG were re-examined on the eighth, tenth, and twelfth hospital days, respectively. MIBG, BMIPP, and TF showed reduced uptake in order of severity. On the fourteenth hospital day, CAG and LVG were re-examined. Coronary vasospasm provocation test was negative using ergonovine and acetylcholine, and LVG did not demonstrated any sign of asynergy. We considered that this case was "Takotsubo" cardiomyopathy and might be caused by microvascular spasm.

3-Iodobenzylguanidine↗

PubMed2000

Echocardiographically documented acute aortic insufficiency induced by Amplatz left guide catheter.

This paper examines a case of sudden systolic pressure fall, tachycardia, low pulse pressure, and high pulmonary artery wedge pressure due to acute aortic insufficiency which was induced by an Amplatz left (AL-1) guide catheter used for better guide support during percutaneous transluminal coronary angioplasty of the right coronary artery. AL guide catheters can cause acute aortic insufficiency, of which practitioners should be aware when sudden hemodynamic collapse occurs.

Journal Article↗

PubMedDate not supplied

Identification of exercise-induced left ventricular systolic and diastolic dysfunction using gated SPECT in patients with coronary artery disease.

BACKGROUND: We investigated whether poststress left ventricular dysfunction in patients with coronary artery disease may be confirmed at 30 minutes after exercise using newly modified quantitative gated single photon emission computed tomography (QGS) software that can evaluate systolic and diastolic function. METHODS AND RESULTS: In this study 28 control subjects, 26 patients with angina pectoris (AP), and 27 patients with old myocardial infarction (MI) who had undergone revascularization were included. Same-day exercise/rest gated technetium 99m tetrofosmin single photon emission computed tomography was performed. QGS was used with a temporal resolution of 32 frames per R-R interval, and a left ventricular volume curve was reconstructed. From the fitted volume curve and its first derivative curve, we derived the ejection fraction (EF), peak ejection rate (PER), peak filling rate (PFR), and time to PFR (TPFR). In patients with AP and MI, the values for EF, PER, and PFR were lower after stress than at rest. TPFR was significantly prolonged in patients with MI after stress. In control subjects, EF, PER, PFR, and TPFR were not changed. CONCLUSIONS: Modified QGS software successfully indicated the changes in systolic and diastolic function. In patients with AP and MI, poststress systolic and diastolic dysfunction was identified 30 minutes after exercise.

Angina Pectoris↗