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Biomedical subjects

M Yamazoe

Publications and source records attributed to M Yamazoe.

At least 73 records · Page 4Linked to original sources
PubMed1987

A case of heterozygous Fabry's disease with a short PR interval and giant negative T waves.

A 55 year old woman with heterozygous Fabry's disease presented with cardiac symptoms. The electrocardiogram showed a PR interval of 0.12 s and giant negative T waves, suggesting apical hypertrophic cardiomyopathy. Endomyocardial biopsy, however, revealed myelin like substances characteristic of Fabry's disease. Increasing thickness of the left ventricular wall was seen by echocardiography over a period of five years. A deficiency of alpha galactosidase activity in the leucocytes confirmed the diagnosis of Fabry's disease, although this patient had neither angiokeratoma or proteinuria. The possibility of Fabry's disease should be considered in patients with cardiomegaly of unknown cause and the following electrocardiographic abnormalities: a PR interval less than or equal to 0.12 s, high voltage QRS complexes in the left precordial leads, and giant negative T waves.

Electrocardiography↗
PubMed1986

Cross-reaction of synthetic alpha-(1----3)-branched glucans with rabbit anti-N4 dextran.

Cross-reactions of four synthetic branched glucans (3-O-alpha-D-glucopyranosyl-(1----6)-alpha-D-glucopyranans: V39, V17, V37, and V32, each containing one unit glucose branches amounting to 11-12%, 33-43%, 50-54%, and 71-100%, respectively) with rabbit anti-N4 dextran were examined. All four samples precipitated antibodies raised in rabbits by injecting N4 dextran-concanavalin A conjugate. The ability of glucans to precipitate antibody depended on the quantity of branches, samples with more branches precipitating less antibody nitrogen under the same conditions. This may indicate an inhibitory effect of the branches on precipitation. Oligosaccharide inhibition assay showed that the precipitation reactions were specific for (1----6)-alpha-D-glucopyranosyl linkages, and the maximum size of the alpha-(1----6)-specific antibody combining site corresponded to isomaltopentaose. Determination of antibody nitrogen and glucan in the precipitates indicated that the ratios of one combining site of antibody to numbers of glucose residues were 1:9 (V39), 1:11 (V17), and 1:16 (V37) in the extreme antibody excess region. A synthetic sample of manno-glucan ((1----6)-alpha-D-glucopyranan containing about 27% of randomly linked 3-O-alpha-D-mannopyranosyl side chains) also reacted with the same antibody.

Animals↗
PubMed1986

Immunochemical similarity of synthetic alpha-(1----3)-branched D-glucans to dextran B1375.

Anti-dextran B1375 antibodies were raised in rabbits by injecting formalin-killed Leuconostoc mesenteroides strain NRRL B1375, and the anti-dextran serum was used to examine native dextran B1375, and synthetic linear and four alpha-(1----3)-branched alpha-(1----6)-D-glucopyranans for similarities. The antiserum reacted with the homologous dextran B1375 and also with all the synthetic linear and branched glucans. Precipitation and precipitation-inhibition studies indicated that the antiserum contained at least three groups of antibodies with different specificities, the first specific for linear alpha-(1----6)-D-glucopyranan structure, the second specific for alpha-D-glycopyranosyl-(1----3)-branching and the last specific for another, unknown structure present in the dextran B1375 molecule. Two samples of the synthetic branched glucans were shown to be immunochemically the most similar to natural dextran B1375 by inhibition experiments.

Antibodies↗
PubMed1986

A case of atrial septal defect complicating myocardial infarction. Severe heart failure induced by balloon occlusion of ASD.

A 58 year old man with an acute, extensive anterior myocardial infarction was found to also have an atrial septal defect secundum. A cardiac catheterization study showed a large left to right shunt (Qp/Qs: 6.0). Since other clinical findings were not consistent with the prolonged existence of a large shunt, we considered it to be secondary to the myocardial infarction. Balloon occlusion of the ASD was carried out to predict the hemodynamics after the surgical correction, which soon resulted in severe left ventricular failure. Therefore, an operation was not feasible in this case.

Cardiac Catheterization↗
PubMed1986

Evaluation of left ventricular residual function using postextrasystolic potentiation. Relation between systolic time intervals and angiographic study.

The effects of postextrasystolic potentiation (PESP) on systolic time intervals and left ventricular wall motion were studied during diagnostic cardiac catheterization in 20 patients (4 normal individuals, 11 patients with coronary artery disease and 5 patients with idiopathic dilated cardiomyopathy). Postextrasystolic changes in the aortic pressure and systolic time intervals were measured from the electrocardiogram and aortic pressure tracing. After a micromanometer-tipped catheter was positioned in the ascending aorta just above the aortic valve, a single ventricular premature beat was introduced using an R-wave coupled stimulator. PESP was then studied during left ventriculography which was undertaken simultaneously in the right anterior oblique 30 degrees and left anterior oblique 60 degrees positions. Following two or three normal sinus beats, a right ventricular extrastimulus was delivered again under the same stimulating condition. PESP in all patients caused a decrease in the ratio of the preejection period to the left ventricular ejection time (PEP/ET). The average percent decrease was 21% (from 0.429 +/- 0.162 to 0.339 +/- 0.102, p less than 0.001). The left ventricular ejection fraction (EF) increased in all patients with PESP from 0.52 +/- 0.20 to 0.61 +/- 0.17 (p less than 0.001). The postextrasystolic changes in the PEP/ET ratio and EF were greater in patients with low cardiac performance. There was a good correlation (r = -0.85, p less than 0.001) between the changes in the EF and those in PEP/ET in PESP. Thus, it is possible to determine left ventricular residual function (the postextrasystolic change in the global EF) using the postextrasystolic change in PEP/ET in patients with coronary artery disease and dilated cardiomyopathy.

Adult↗
PubMed1986

[Quantitation of coronary artery lesions by 2-4 hour stress-myocardial clearance of thallium-201].

The stress-redistribution thallium-201 scintigraphy and thallium-201 washout method have limitations in their ability to detect individual coronary lesions in patients with multivessel coronary artery disease. The purpose of this study is to investigate the value of the quantitative planar method using the dynamics of thallium-201 redistribution after exercise. We observed the patterns of thallium clearance in the late stages (at 2 and 4 hrs) which are characteristic of decreased myocardial blood supply by the obstructed coronary arteries. In 20 subjects, quantitative thallium scintigrams (planar image and circumferential count profile) and blood samples for thallium concentration were obtained immediately, and 2 and 4 hrs after maximal treadmill exercise. Coronary angiography was performed in all subjects, and 16 patients had coronary artery disease (CAD) and four were normal. The rate of thallium clearance from the blood (TCB) was compared with the rate of thallium clearance from each segmental lesion of the myocardium (TCM) between the 2- and 4-hr images. The system adopted for assignment of myocardial regions to individual coronary arteries has been used as an approach to localization of anatomic disease. In the four patients with normal coronary arteries, TCM exceeded TCB in all regions of all images (specificity 100%). Fourteen of the 16 CAD patients had at least one region where TCM was less than TCB (sensitivity 88%). Ten of the 14 patients with multivessel CAD had multiple regions where TCM was less than TCB (sensitivity 71%). All of the six patients without multivessel CAD (four with normal coronary arteries and two with one vessel disease) did not have multiple regions where TCM was less than TCB (specificity 100%). Quantitative thallium scintigraphy showed sensitivities of 86%, 56% and 91% in the left anterior descending artery, the circumflex coronary artery and right coronary artery, respectively. These results showed that decreased TCM in the late stage is characteristic of myocardial regions where blood is supplied by the diseased coronary arteries. This finding may improve diagnostic sensitivity under the condition of multivessel coronary artery disease.

Adult↗
PubMed1985

Distribution of neuropeptide Y in the lower brainstem: an immunohistochemical analysis.

The distribution of neuropeptide Y (NPY)-like immunoreactive (NPYI) structures in the rat lower brainstem was examined by means of indirect immunofluorescence or peroxidase-antiperoxidase methods. In addition to the well known immunoreactive NPYI containing cell groups, the present study demonstrated a much wider distribution of immunoreactive NPYI cells in the lower brainstem, i.e. substantia nigra pars lateralis, interpeduncular nucleus, inferior colliculus, nucleus cuneiformis, dorsal tegmental nucleus of Gudden, nucleus laterodorsalis tegmenti, nucleus vestibularis medialis, nucleus vestibularis inferioris, in the fasciculus longitudinalis medialis and nucleus parvocellularis compacta. We also demonstrated an extensive network of NPYI fibers in various areas of the lower brainstem including the auditory system, viscerosensory system, visceromotor system, raphe nuclei, reticular formation, parabrachial area, locus coeruleus and interpeduncular nucleus, etc. The possible importance of NPY is briefly discussed.

Animals↗
PubMed1985

Assessment of the contribution of atrial systole to ventricular filling by cardiac pacing.

Analysis of beat to beat changes in left ventricular (LV) ejection time during cardiac pacing was utilized to assess the atrial contribution to ventricular filling in 30 consecutive patients undergoing diagnostic cardiac catheterization. The group consisted of 9 normal subjects, 18 with coronary artery disease and 3 with congestive cardiomyopathy. The recordings of aortic pressure were made during atrial pacing and ventricular pacing at a rate 5 to 10 beats/min above each individual's sinus rhythm. During ventricular pacing, LV ejection time was the longest when an atrial contraction preceded a ventricularly paced beat by a physiologic interval and was approximately similar to that obtained during atrial pacing (maxET). When the atrial systole occurred with or followed the ventricularly paced contraction, LV ejection time was decreased (minET). Since maxET occurred in the presence of an effective atrial contraction to ventricular filling and minET in the absence of this contraction, the atrial contribution to ventricular filling was calculated as (maxET-minET)/maxET X 100 (%). LV volumes at end-systole (V1), before atrial contraction (V2) and at end-diastole (V3) were obtained according to the area-length method by tracing the silhouette of left ventriculograms using a computer system. The atrial contribution was calculated from LV volumes using the formula (V3-V2)/(V3-V1) X 100 (%). There was a good correlation (r = 0.88) between the atrial contributions calculated from LV ejection times and those calculated from LV volumes. In the patients with coronary artery disease and with congestive cardiomyopathy, the atrial contribution was significantly greater than in the normal subjects. The measurement of LV ejection time during ventricular pacing may be a clinically useful screening procedure to identify patients in whom physiologic pacing may be indicated.

Adult↗
PubMed1984

Distribution of six neuropeptides in the nucleus tractus solitarii of the rat: an immunohistochemical analysis.

Distribution of substance P-, [Leu]enkephalin-, cholecystokinin-8-, neurotensin-, avian pancreatic polypeptide- and gamma-melanocyte stimulating hormone-like immunoreactive structures were investigated in the nucleus tractus solitarii of the rat by means of the indirect immunofluorescence method. The density of the immunoreactive structures varied markedly according to neuropeptides or subnuclei, with the medial and commissural nuclei containing the highest density. This suggests that the peptides examined play a role in cardiovascular function. However, as seen in the substance P- and [Leu]enkephalin-like immunoreactive structures, these peptides were widely distributed in the nucleus tractus solitarii in addition to the commissural and medial nuclei; a high density of immunoreactive fibers in the ventral, dorsolateral and intermediate subnuclei. In addition to the immunoreactive fiber plexus, a group of immunoreactive cells was also identified in the subnuclei mentioned above. These findings strongly suggest that substance P- and [Leu]enkephalin-like immunoreactive structures are involved not only in cardiovascular function but also in other functions such as respiration, at least in the rat. Finally, the present study demonstrated that the area postrema, particularly its lateral portion, contains various neuropeptide-like structures, both neurons and fibers, substance P-, [Leu]enkephalin-, cholecystokinin-8- and neurotensin-like immunoreactive neurons and fibers, and avian pancreatic polypeptide- and gamma-melanocyte stimulating hormone-like immunoreactive fibers.

Animals↗
PubMed1984

Three-dimensional characteristics of the intramyocardial microvasculature of hypertrophied human hearts.

The three-dimensional architecture of the intramyocardial microvasculature was demonstrated in hypertrophied human hearts using Evan's method: scanning electron microscopic observation of the cardiac muscle chemically digested by hydrochloric acid and collagenase. Twenty autopsied hearts, which had already been fixed in 10% formalin, were investigated, including 17 hypertrophied hearts (mean cardiac weight, 587 g) and three control hearts (mean cardiac weight, 238 g). The luminal surfaces of the arterioles were characterized by the coiled arrangement of their smooth muscle cells. The structure of these vessels was not significantly different in hypertrophied and normal hearts. The capillaries showed great changes in the hypertrophied muscle: capillaries running on the body of the myofibres, in loop form on disorganized myofibres, and protruding into myofibres and/or probably penetrating through them. These features indicated an increase in the ratio of capillary/myofibre in hypertrophied human hearts. In hypertrophied hearts the venules had a more developed system than normal hearts, but without change in their basic architecture.

Adult↗
PubMed1984

Optimal pacemaker sensing with respect to amplitude and slew rate of intracardiac electrograms: theoretical analysis by computer simulation.

The optimal amplitude and slew rate of intracardiac electrograms for pacemaker sensing were examined on a theoretical basis by computer simulation. The simulation was based on the concept that it is the voltage at the position of the pacing electrode in an electrical field of a moving electrical dipole. By changing the distance between the electrode and the myocardium and the moving velocity of the electrical dipole, simulated ECGs with arbitrary amplitudes and slew rates were generated by the computer and fed to a bandpass filter. This filter was equivalent to those assembled in some models of permanent pacemakers and had a center pass-band frequency of 50 Hz and a Q of 1.0. The outputs of the filter were measured. The results showed that, for pacemakers sensing, simulated intracardiac electrograms with high amplitude should have high slew rates and those with low amplitudes should have low slew rates, although the absolute values depend on the characteristics of the bandpass filter and the sensing threshold of the pacemaker.

Computers↗
PubMed1983

[Left ventricular regional wall motion after correction of tetralogy of Fallot].

Cardiac function and left ventricular regional wall motion were examined using two-dimensional echocardiography in 40 post-operative patients of tetralogy of Fallot (TOF) of an average of 13 years after the correction. From the data of treadmill exercise test and cardiac catheterization, patients were classified into two groups; cases with complete ability for treadmill test (Group A, n = 22), and disabled for the test and the right ventricular systolic pressure above 50 mmHg (Group B, n = 18). Compared with the control group (n = 10), the patient groups had greater cardiothoracic ratios (CTR) and right/left ventricular dimensions (RVd/LVd) (p less than 0.001), and Group B had a greater CTR and RVd/LVd than Group A (respectively p less than 0.001). Compared with the control group, the patient groups had no significant differences in corrected ejection time, fractional shortening and mean velocity of circumferential fiber shortening, and no difference was noted between Group A and Group B. Left ventricular regional wall was divided into 12 segments around the left ventricular circumference on the two-dimensional short-axis view and the regional wall motion was evaluated on the basis of [(diastolic-systolic)/diastolic left hemiaxial length X 100%] values. In Group B, akinetic or dyskinetic wall motion was visualized at the interventricular septum and left ventricular posterior wall, but there was no abnormal motion in the control group and Group A. We concluded that even in postoperative patients with preserved cardiac function at rest, some of them had abnormal left ventricular regional wall motion due to the persistent right ventricular overload or corrective patch, resulting in low exercise capacity.

Adolescent↗
PubMed1982

Glycogen aggregates in cardiac muscle cell: a cytopathological study on endomyocardial biopsies.

Glycogen aggregates in the cardiac muscle cell, which have been frequently demonstrated in endomyocardial biopsies under the transmission electron microscope, were studied using the optical microscope in order to clarify their histopathological significance in various heart diseases. The right ventricular muscle biopsies were obtained from the following 120 patients: 24 cases of congestive cardiomyopathy, 26 of hypertrophic cardiomyopathy, 28 of atrial septal defect, 6 of primary pulmonary hypertension, 31 of bradyarrhythmic hearts and 5 controls. The tissue specimens were fixed with glutaraldehyde and osmium tetraoxide, and embedded in epoxy resin. Semi-thin sections from these specimens were dyed with tribasic staining originated by KUROTAKI (1972). Under the optical microscope, glycogen is clearly identified by its forming red stained areas which are seen not only in the subsarcolemmal layers and the perinuclear region, but also in the intermyofibrillar zones. The glycogen aggregates are more frequently observed in the specimens from the atrial septal defects and the bradyarrhythmic hearts than in the other cases. Thus, observation of glycogen aggregates reveals notable differences in appearance depending on the kinds of diseases. In the bradyarrhythmic hearts, the glycogen aggregates can be more readily observed in specimens from younger patients than in elderly ones. Furthermore, the glycogen aggregates appear regardless of both the grades of hypertrophy and degeneration in myocardial cells. These results do not agree with previous reports that the occurrence of glycogen is proportional with the grade of cardiac cell hypertrophy and/or damage.

Adult↗