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Biomedical subjects

N Fukuda

Publications and source records attributed to N Fukuda.

At least 289 records · Page 16Linked to original sources
PubMed1987

[Musical systolic murmur produced by oscillation of the systolic anterior motion of the mitral apparatus: relation to the genesis of Still's murmur].

The genesis of a musical systolic murmur produced by systolic anterior motion (SAM) of the mitral apparatus was investigated in four patients using phonocardiography and echocardiography. Two patients (Case 1 and 3) had hypertrophic cardiomyopathy (one, the obstructive type; the other, the nonobstructive type) and the remaining two (Case 2 and 4) had redundant chordae tendineae. 1. In every patient, regular oscillation of the SAM was observed, coinciding in time with the musical systolic murmur, which was simultaneously recorded. The fundamental frequency of the musical systolic murmur was recorded as integrally multiplied numbers of the SAM. Such regular oscillation was not observed in the echograms of other cardiac structures. In a patient with hypertrophic obstructive cardiomyopathy (Case 1), both the amplitude and oscillation of the SAM were increased by amyl nitrite inhalation, and were decreased by angiotensin II infusion. Correspondingly, the intensity of the musical murmur showed similar reaction. No findings suggestive of mitral valve prolapse or mitral regurgitation were found in any patients. Therefore, the oscillation of the SAM produced by blood ejected from the left ventricle was considered the source of the musical systolic murmur in these patients. 2. Two patients with redundant chordae tendineae had no clinical abnormalities except for chordal redundancy; therefore, the musical murmur in these cases was considered to be functional. Particularly, one of them was compatible in character with the so-called Still's murmur. In conclusion, the regular oscillation of the SAM may be the source of the musical systolic murmur, and they must be taken into consideration as part of the genesis of Still's murmur.

Adolescent↗
PubMed1987

[Mitral regurgitation in mitral valve prolapse: its mechanisms and time course].

To clarify the mechanisms and time course of mitral regurgitation (MR) in mitral valve prolapse (MVP), the relationship between the timing of MR flow patterns on pulsed Doppler echocardiography and phase of mitral valve prolapse on two-dimensional echocardiography was investigated. 1. Thirty-seven patients with MVP were followed by pulsed Doppler echocardiography for one to six years with an average of 2.5 years. At the initial examination, the patients were classified in five subsets on the basis of the presence or timing of MR: 10 without MR, five with early systolic MR, one with mid-systolic MR, 15 with late systolic MR and six with pansystolic MR. During the follow-up period, the timing of MR did not change in 21 patients (three with no MR, five with early systolic MR, seven with late systolic MR and six with pansystolic MR). Various changes were observed in 16 patients, i.e., developments of late systolic MR from no MR in four, of pansystolic from no MR in three, from late systolic MR in five and from mid-systolic MR in one, and disappearing late systolic MR in three. 2. Mitral annular diameter and the prolapsing phase of 118 patients with MVP (44 without MR, eight with early systolic MR, 30 with late systolic MR and 36 with pansystolic MR) were examined by long-axis two-dimensional echocardiography. The mitral annular diameter in patients with early systolic MR was significantly less than that of other MR groups, and the diameter in patients with pansystolic MR was markedly increased. The timing of MR was determined according to the prolapsing phase and the grade of the prolapse and the systolic size of the mitral annulus. Six of the eight patients with early systolic MR first had early systolic prolapse of either mitral leaflet, and then the regurgitant gap of the mitral valve orifice was plugged by the prolapsing leaflet and/or the narrowed mitral annulus during mid-to-late systole. In 18 of the 30 patients with late systolic MR, the grade of prolapse of the mitral valve during mid-to-late systole was more severe, compared with that of early systole. The results of the present study indicated that the occurrence of MR in MVP is various in timing (early, mid-, late or pansystole) and shows various changes the during follow-up study, and that pulsed Doppler echocardiography allows phase analysis of MR in MVP.

Adult↗
PubMed1986

Fast dynamic study in cardiac positron CT using 13N-ammonia in man.

Fast dynamic studies with positron computed tomography (PCT) of the heart have been relatively few because of the technical limitations of prevalently used PCT devices. In the present study, we used a high-sensitivity, whole-body multislice PCT device (POSITOLOGICA-II) and performed serial 6-s PCT scans after the intravenous bolus injection of 13N-ammonia in 15 cardiac patients and 5 normal subjects. On the first image (0-6 s), 13N activity was primarily in the right atrium and ventricle. On the third image (12-18 s), it was primarily in the left atrium and ventricle. These blood-pool images permit evaluation of size and configuration of ventricles and atria in cardiac patients and normal subjects. Clearance of 13N activity in the blood pools and lungs occurred primarily during the 1st min. Thereafter, the myocardial images were delineated. In patients with heart failure, delayed clearance of the tracer from the blood pools and lungs was observed. The results indicate that initial passage of the tracer through the heart can be observed with the use of fast dynamic PCT.

Adult↗
PubMed1986

Effects of intravenous administration of a calcium antagonist on prostaglandins and thromboxane in plasma and urine in humans.

The effects of a calcium antagonist [Nicardipine hydrochloride (NH)] on the prostaglandin [prostaglandin E2 (PGE2), and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha)] and thromboxane B2 levels in the blood and urine were examined in 6 patients with essential hypertension following intravenous infusion of NH for 120 minutes. At the same time, the plasma renin activity (PRA), plasma aldosterone concentration (PAC), and plasma and urinary electrolyte levels were also determined. During NH administration, the blood pressure was significantly decreased (p less than 0.05) with an increased pulse rate (p less than 0.05). PRA was significantly increased after NH loading (p less than 0.05) but PAC showed no change. The plasma PGE2 and 6-keto-PGF1 alpha levels tended to increase slightly, while the blood thromboxane B2 level showed a decreasing tendency. The 6-keto-PGF1 alpha to thromboxane B2 ratio was significantly increased after NH loading as compared to the preloading ratio (p less than 0.05), and then returned to the preloading value at about 30 minutes after discontinuation of NH loading. The urinary excretions of PGE2, 6-keto-PGF1 alpha and thromboxane B2, PGE2 and 6-keto-PGF1 alpha tended to decrease after NH loading. In particular, the decrease in PGE2 was statistically significant (p less than 0.05). No change occurred in the urinary excretion of thromboxane B2. The above findings indicate that NH increased the plasma 6-keto-PGF1 alpha to thromboxane B2 ratio but decreased the urinary excretion of prostaglandins. In addition, the possible involvement of an enhanced 6-keto-PGF1 alpha/thromboxane B2 ratio in part of the hypotensive mechanism of NH is suggested.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

Effects of dibutyryladenosine 3',5'-monophosphate on steroid biosynthesis in humans.

The effects of dibutyryladenosine 3', 5'-monophosphate (DBcAMP), a nucleotide analogue, on blood pressure, serum electrolytes and plasma corticoid concentrations were investigated in 10 normotensive healthy subjects who received a constant diet containing 5-8 g sodium chloride in hospital. The systolic blood pressure did not change after infusion of 0.25 or 0.33 mg/kg/min of DBcAMP for 20 min. On the other hand, the diastolic blood pressure was significantly decreased after the infusion of DBcAMP. The levels of serum sodium and potassium were significantly decreased after the infusion of DBcAMP. After infusion of 0.25 mg/kg/min of DBcAMP for 20 min, the changes in plasma levels of 6 corticoids [progesterone, deoxycorticosterone (DOC), 18-hydroxy-deoxycorticosterone (18-OH-DOC), corticosterone, cortisol and dehydroepiandrosterone sulfate (DHEA-S] revealed no significant changes. After infusion of 0.33 mg/kg/min of DBcAMP for 20 min, the plasma levels of cortisol, corticosterone and 18-OH-DOC were significantly increased and the changes in plasma levels of aldosterone showed a tendency to increase but this was not significant. The plasma levels of DOC and DHEA-S were not appreciably changed, while the plasma levels of progesterone were significantly decreased after the infusion of 0.33 mg/kg/min of DBcAMP. It is speculated therefore that DBcAMP may act to enhance the activity of the sodium-potassium pump and to promote steroid biosynthesis dose-dependently in humans.

Adrenal Glands↗
PubMed1986

[Mitral component of the first heart sound in complete left bundle branch block: the mechanism of the decreased intensity].

To clarify the mechanism of the reduced intensity of the mitral component of the first heart sound (IM) in complete left bundle branch block (LBBB), electrocardiograms, phonocardiograms, apexcardiograms and mitral valve echograms of 12 patients with LBBB (LBBB group) and 13 normal subjects (normal group) were simultaneously recorded. The first derivative of the apexcardiogram was also studied. One of the 12 patients had an intermittent LBBB. There was no significant difference in the P-Q interval between the two groups. The following results were obtained: 1. In the LBBB group; 1) The intensity of the IM, expressed as a ratio of the amplitude of the IM to that of the aortic component of the second heart sound (IIA) on the apical phonocardiograms, was significantly reduced except in one patient who had a relatively short P-Q interval. 2) The timings of the onset of the upstroke of the apexcardiogram and mitral valve closure were significantly and equally delayed. 3) The amplitude of the mitral valve echogram at the onset of the upstroke of the apexcardiogram (end-diastolic amplitude of the mitral valve) was significantly decreased. The closing velocity of the mitral valve was also decreased. 4) The amplitude ratio (H2/H1) and the rate of rise (A) of the apexcardiogram at the onset of the IM were significantly decreased. 2. The intensity of the IM, H2/H1 and A of the apexcardiogram at the onset of the IM were compared for three cases with nearly equal end-diastolic mitral valve amplitudes in each group. The intensity of the IM was apparently reduced in the LBBB group, compared with that of the normal group, and its intensity correlated inversely with H2/H1 and A. These results indicate that the reduced intensity of the IM in LBBB is caused mainly by the decreased amplitude of the mitral valve excursion at the onset of left ventricular contraction. An additional cause is the decreased tension on the closed mitral valve resulting from the slow rate of left ventricular pressure rise at the onset of the IM.

Adult↗
PubMed1986

[Mode of left ventricular diastolic filling in hypertrophic cardiomyopathy as studied by pulsed Doppler echocardiography and multigated blood pool scan].

The clinical significance of the mode of left ventricular (LV) diastolic filling in hypertrophic cardiomyopathy was studied by the LV inflow velocity patterns (LVIF) of pulsed Doppler echocardiography and LV early diastolic filling rates (V2) of radionuclide (RI) angiography. The relationship between the deceleration time (DT) obtained from LVIF and the V2 was evaluated in 34 patients with nonobstructive hypertrophic cardiomyopathy (HCM) and in nine with obstructive hypertrophic cardiomyopathy (HOCM), and the results were compared with those of 10 patients with dilated cardiomyopathy (DCM), of two with restrictive cardiomyopathy (RCM), and of 19 normal subjects. HCM was subdivided into the following groups according to V1-DT relationships: Group 1 with prolonged DT and decreased V1, Group 2 with normal or short DT and normal V1, and Group 3 with normal or short DT and decreased V1. There were significant negative correlations between V2 and DT in Groups 1 and 2 of HCM, normal and HOCM. However, there were significant positive correlations in Group 3 of HCM, DCM and RCM. Nearly all patients in Group 3 had decreased LV ejection fraction and % fractional shortening, distinct B-B' step formation of the mitral valve echogram, and huge A wave of the apexcardiogram. These findings suggested that the LV rapid filling interval gradually became shorter because the LV contraction is decreased as myocardial fibrosis develops in HCM, and that we must pay attention to the diagnosis of such abnormalities, similar to those of DCM or RCM.

Cardiomyopathy, Dilated↗
PubMed1986

[Primary pericardial malignant mesothelioma associated with constrictive pericarditis: a case report].

A case of primary pericardial malignant mesothelioma was presented, which initially had a relatively large quantity of pericardial fluid, followed by constrictive pericarditis. The patient was a 43-year-old woman whose chief complaint was dyspnea and admitted to our hospital in March, 1984. Because of a relatively large quantity of pericardial fluid was observed. In April, drainage of the fluid and pericardiotomy were performed with marked relief of symptoms. She was discharged, but her dyspnea recurred in August, and she was readmitted. After the second admission, the chest radiograph showed a cardiothoracic ratio of 62%, and her electrocardiogram showed low voltage. A pericardial knock was recorded, and the timing of this sound coincided with that of the peak of the early distolic wave of the mitral flow velocity pattern. A jugular pulse tracing showed a deep and sharp y descent. The diastolic pressure curve of the right ventricle revealed a dip and plateau pattern. The echocardiographic finding was characterized by abnormal systolic motion and an early diastolic dip of the interventricular septum, multiple abnormal echoes and thickening of the pericardium, and an abnormal mass echo in the left atrial cavity. Based on the above examinations, pericardiotomy was performed, but the tumor was not entirely resected. The histological diagnosis was malignant mesothelioma.

Adult↗
PubMed1986

[Nuclear magnetic resonance imaging of the brainstem: evaluation of the normal structures and small lesions].

Nuclear magnetic resonance (NMR) imaging of the brainstem region from 12 asymptomatic individuals were reviewed in addition to these of 12 patients with various symptoms of small brainstem lesions. Abnormalities consisted of 3 cases of multiple sclerosis, 1 case of neuro-Behçet disease, 5 cases of infarction and hematoma and 3 cases of degenerative disease. NMR transverse imaging using inversion recovery sequence was able to locate many of the normal intra-axial brainstem nuclei, such as the periaqueductal gray matter, the red nucleus, the substantia nigra, the pontine nuclei, the pontine reticular nuclei, the facial nerve nucleus and so on in an about half of 12 asymptomatic individuals. The remarkable gray-white matter differentiation was obtained on NMR imaging using inversion recovery sequence and enabled the internal structures to be visualized within the brainstem. In addition, the midsagittal imaging provided an excellent demonstration of anatomical relationships of the brainstem and surrounding structures. In the diencephalic region, the mamillary body, the anterior commissure and the optic chiasma were also demonstrated on the midsagittal imaging. The lesions within the brainstem were vaguely shown on X-ray computed tomography in 6 of 12 patients but NMR imaging using inversion recovery or spin echo sequence provided more detailed data and revealed clear small lesions, such as the demyelinated plaques of multiple sclerosis and lacunar infarcts in 9 of 12 patients. Especially, in 2 of 3 multiple sclerosis patients, the plaques of the brainstem were definitely identified on NMR imaging only and the accurate localized lesion which was responsible for the facial myokymia or the Foville syndrome was identified.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗