PubMed Health⌕ Search

Biomedical subjects

H Ootsubo

Publications and source records attributed to H Ootsubo.

12 recordsLinked to original sources
PubMed1995

[Bilateral ankle ulcers associated with hydroxyurea therapy for chronic myelogenous leukemia].

Bilateral ankle skin ulcers developed in a 61-year-old man in the chronic phase of chronic myelogenous leukemia receiving hydroxyurea therapy. The circulating immune complex (anti-C3d antibody) was high in this case, but vasculitis was not observed in the pathological findings of biopsied skin materials. This association has been reported in patients who had chronic myelogenous leukemia or other myeloproliferative disorders and were treated with hydroxyurea. It is likely that skin ulcers are caused by hydroxyurea.

Foot Ulcer↗
PubMed1986

Significance of collateral circulation on peri-infarct zone: assessment with stress thallium-201 scintigraphy.

To evaluate the significance of collateral circulation on peri-infarct zone, stress myocardial scintigraphy and contrast left ventriculography (LVG) were performed in 38 patients with recent myocardial infarction (MI). All patients had at least one completely occluded coronary artery corresponding to the infarct area. In patients with good collaterals, stress induced transient enlargement of the perfusion defect, however, in those with poor or no collaterals the enlargement did not occur (p less than 0.05). Wall motion abnormality on LVG was significantly milder in the former patients than in the latter (p less than 0.001). Transient enlargement of the perfusion defect after stress and milder left ventricular asynergy were more frequently observed in patients with anterior MI and good collaterals. These observations indicate that good collaterals may keep some myocardium in the peri-infarct zone viable.

Adult↗
PubMed1985

Dual-frame image-freezing unit for two-dimensional echocardiography. Preliminary clinical report.

We developed a "dual-frame image-freezing unit", which enables acquisition of two stop-frame images of the two-dimensional echocardiogram at different points within one cardiac cycle. We assessed the clinical usefulness of this unit by estimating the left ventricular ejection fraction with apical biplane two-dimensional echocardiography in 25 patients who underwent left ventricular biplane cineangiography. The unit functioned successfully in all instances. It was much easier to obtain the left ventricular end-diastolic and end-systolic echocardiographic images than to obtain such images using conventional videotape play-back. The quality of the images obtained by this unit was better than those obtained from videotape play-back. The echocardiographic estimates of the left ventricular ejection fraction showed an excellent correlation with estimates obtained by contrast left ventricular cineangiography. We conclude that this dual-frame image-freezing unit can be satisfactorily applied for the assessment of the left ventricular ejection fraction by two-dimensional echocardiography.

Adult↗
PubMed1984

Alpha adrenergic receptor activity of epicardial coronary artery in the anesthetized dog.

The epicardial coronary artery plays an important role not only as a conduit artery but also as a locus of coronary spasm. Accordingly, diameter change of the large epicardial coronary artery of the in situ canine heart was continuously measured by ultrasonic dimension gauge technique and the effects of alpha adrenergic stimulation on the caliber were studied. After the intravenous administration of phenylephrine the aortic pressure increased by 28 mmHg, however, the left circumflex coronary artery diameter decreased by 3.4% (p less than 0.01). Norepinephrine and sciatic nerve stimulation after propranolol (1 mg/kg) induced coronary vasoconstriction by 1.3 (p less than 0.025) and 2.5% (p less than 0.05) against the obvious increases of aortic pressure by 16 and 19 mmHg, respectively. Thus alpha adrenergic stimulation, in situ in dogs, was shown to directly constrict the large epicardial coronary artery.

Adrenergic alpha-Agonists↗
PubMed1982

Preocclusive perfusion area as a determinant of infarct size in a canine model.

The extent of myocardial infarction related to the pre-occlusive perfusion are was quantitatively evaluated in a canine model. The perfusion area was determined preocclusively by selective injection of tracer microspheres into the coronary artery in question, then the main trunk and a small lateral branch of the left circumflex coronary artery was occluded in group 1 (10 dogs) and group 2 (10 dogs), respectively. Rapid freezing was used to prepare autoradiographic samples for determination of the perfusion are along with samples for dehydrogenase staining in order to delineate the extent of myocardial infarction. The relationship between perfusion area and infarct size was examined in 50 micrometers thick samples from base, middle and apex of the ventricle and a direct linear correlation between the perfused (P) and infarcted area (I) in the left ventricle (LV) was noted regardless of the perfusion size or the location in the ventricle. The linear relationship I = 0.93P - 4.9 (r = 0.95, P less than 0.001) was obtained in all 20 dogs. Transmural extent of necrosis was larger in the endocardium than in the epicardium, thereby representing a more salvageable myocardium in the epicardium. It is concluded that the preocclusive determination of perfusion are by high resolution autoradiography is a useful method of obtaining physiological perfusion not affected by ischaemia. Also the infarct size when standardized by the perfusion area is mainly influenced by transmural location but not by the spacial geometry or the size of the occluded area.

Animals↗
PubMed1981

Continuous measurement of coronary artery diameter in situ.

The diameter of the coronary artery was measured in dogs in situ by an ultrasonic dimension gauge using 10-MHz piezoelectric crystals. Underestimation in measurements due to crystal rotation was limited to < 1% by adding a convex lens to the crystal. A pair of small 10- and 5-MHz crystals were sutured to the adventitia of the left circumflex coronary artery (LCX) and the descending aorta (Ao), respectively. Using cuff occluders for vessel constriction of the inferior vena cava (IVC) or the Ao, curvilinear relationships between pressure and diameters were obtained. Phasic changes of the aortic as well as coronary diameter were grossly similar to changes in the pressure wave. After intravenous administration of dipyridamole, aortic pressure (AP) decreased by 17% along with 3% decline of the Ao and LCX diameter, however, after nitroglycerin given by the same route, LCX diameter increased by 5% (P < 0.05) despite 16% and 2.3% reductions in AP and Ao diameter, respectively. This ultrasonic technique, which allows continuous measurement of the diameter of small vessels, should provide a new tool for the study of coronary circulation.

Animals↗
PubMed1981

Difference in site and time course of coronary dilating effects of trapidil, nitroglycerin and dipyridamole in anesthetized dogs.

Effects of trapidil, a non-nitrate type coronary vasodilator, nitroglycerin and dipyridamole on epicardial coronary diameter and total coronary resistance were studied in anesthetized open-chest dogs. The epicardial coronary diameter of the left circumflex coronary artery was measured by sonomicrometry and total coronary resistance was calculated by aortic pressure and coronary blood flow. Intravenous administration of Trapidil, as well as nitroglycerin, produced transient decreases in total coronary resistance followed by sustained dilation of the large coronary artery. Dipyridamole increased coronary blood flow by 2.7-fold, whereas diameter of the large coronary artery decreased along with the reduction of aortic pressure. The first peak of the biphasic increases in coronary blood flow and subsequent dilation of the large coronary artery appeared after an i.v. bolus administration of trapidil or nitroglycerin and remained even after beta adrenergic blockade. Intracoronary administration of either drug produced monophasic increases in coronary blood flow along with subsequent dilation of the large coronary artery. Thus, trapidil, like nitroglycerin, directly dilates the large and small coronary arteries.

Animals↗
PubMedDate not supplied

Tissue edema and loss of tracer microspheres in infarcted myocardium.

Microsphere loss from the ischemic myocardium was studied in a canine model after 2 and 7 days coronary occlusion. 10 million tracer microspheres (TM) of 7-10 micrograms diameter were injected into the left atrium before and 15 minutes after left anterior descending coronary artery (LAD) occlusion. To determine the tissue water content, dried tissue weight was measured after desiccation. TM content in the nonoccluded left circumflex coronary artery (LCX) area was unchanged before and after coronary occlusion. In the infarcted area, microsphere loss was maximum at the low flow endocardial region averaging 27% and 42% in 2 and 7 days occlusion, respectively. An inverse linear correlation between TM loss and regional blood flow in 2 (r = -0.82, p less than 0.05) and 7 (r = -0.96, p less than 0.01) days coronary occlusion was noted. Water content was increased in the ischemic endocardium by 4.1 and 5.7% in 2 and 7 days occlusion, thus approximately 17% of TM loss was attributed to tissue edema. These results suggest that there is an ischemia-dependent reduction of TM in the ischemic myocardium and that microsphere migration participates in the major part of TM loss. Thus flow measurements by TM may be invalid when this compound is injected during the active phase of microsphere migration or during water content alterations.

Animals↗
PubMedDate not supplied

Linear relationship between perfusion area and infarct size.

The purpose of this study was to develop a technique measuring the perfusion area of the coronary artery preocclusively and to study the relationship between the perfusion area and infarct size. 125I tracer microspheres were selectively injected into the left circumflex coronary artery (LCX) preocclusively, and then the LCX was ligated. 48 hours later the heart was removed, rapidly frozen, and 50-mu transverse sections were obtained from base, middle and apex of the canine left ventricle, and used for autoradiography to measure perfusion area and for tetrazolium staining to measure infarct size. Dogs were divided into 2 groups: group 1 in which the main trunk of the LCX was occluded to produce large infarct (n = 10) and group 2 in which the distal branch of the LCX was occluded to produce small infarct (n = 10). There was a linear correlation between the perfused and infarcted area regardless of a size or location of the perfusion area involved. These results indicate that the extent of infarction is directly proportional to the perfusion area and is not altered by the location in the ventricle.

Animals↗
PubMedDate not supplied

Constriction of the epicardial coronary artery induced by alpha-adrenergic stimulation.

Effects of alpha adrenergic stimulation on diameter change of the epicardial coronary artery were studied in in-situ canine heart. The diameter of the left circumflex coronary artery (LCX) was continuously measured by 10 MHz PZT crystals applied to the external wall of the LCX. Aortic pressure was measured using high fidelity catheter-tip manometer. Enhanced activity of alpha adrenergic receptor by humoral and/or somatic nerve stimulations caused a reduction of the LCX diameter despite of the systemic pressure rise.

Animals↗