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Biomedical subjects

N Fukuda

Publications and source records attributed to N Fukuda.

At least 253 records · Page 14Linked to original sources
PubMed1990

[Genesis and clinical significance of an apical diastolic rumble in patients with mitral Björk-Shiley valve: a Doppler echocardiographic study].

The genesis and clinical significance of an apical diastolic rumble after replacement with mitral Björk-Shiley prosthesis were studied in 20 patients by left ventricular (LV) inflow dynamics using Doppler echocardiography. 1. The rumble was audible in 17 of the 20 patients (85%). In all but one patient, its intensity was less than Levine 2/6. Duration of the rumble ranged from 248 to 544 (mean 377) msec. There was no case of prosthetic valve dysfunction. Duration of the slow filling wave (SF interval) of the apexcardiogram in 19 cases ranged from 150 to 541 (mean 317) msec, and it correlated significantly with the duration of the rumble (r = 0.95) in 15 cases. 2. In 20 patients, peak velocity of the LV inflow obtained from continuous wave Doppler echocardiograms ranged from 1.17 to 1.89 (mean 1.56) m/sec, and pressure half time (PHT) ranged from 82 to 233 (mean 134) msec. In 19 patients, the SF interval correlated significantly with PHT (r = 0.87), but not with peak inflow velocity. 3. Peak inflow velocity was significantly slower in cases without a rumble than in cases with a rumble. PHT and the SF interval tended to be shorter in the former than in the latter. 4. There was no significant difference in the SF interval, peak inflow velocity and PHT between eight patients with smaller valve sizes (less than or equal to 25 mm) and 12 with larger valve sizes (greater than or equal to 27 mm). 5. There was no obvious relation between the direction of the main LV inflow jet as assessed by Doppler color flow mapping and the presence of the rumble in 19 patients. 6. In 19 patients, the SF interval correlated significantly with left atrial dimension (r = 0.47), but it did not correlate with LV end-diastolic dimension, fractional shortening of the LV, and the peak lengthening rate of LV internal dimension. 7. Three patients with both the rumble and SF lasting 500 msec had prolonged PHT longer than 190 msec. One of these three had congestive heart failure and suspected prosthetic mitral valve stenosis. From these results, we concluded that an apical diastolic rumble after replacement with mitral Björk-Shiley valve is mainly due to the increase in resistance and velocity of the LV inflow, and that both durations of the rumble and the SF intervals as well as PHT of the Doppler echocardiogram are useful in detecting stenosis of prosthetic mitral valves.

Adult↗
PubMed1990

[Relationship between regurgitant flow dynamics and cardiac physical in tricuspid regurgitation: a phono-, mechano- and Doppler echocardiographic study].

To evaluate the relationships between regurgitant flow dynamics of tricuspid regurgitation (TR) and cardiac physical signs, and to clarify the role of atrial function on central venous flow, we investigated physical signs by cardiac auscultation and palpation of the liver. In addition, phonocardiography, jugular venous and hepatic pulse tracings and Doppler echocardiographic recordings were performed. The subjects, 109 patients with Doppler-detected TR, were categorized as an SR group of 42 with sinus rhythm, an Af group of 63 with atrial fibrillation and four with sinus arrest. Thirty-five patients underwent open heart surgery before six months or more. Results were as follows: 1. In the Af group, the maximum systolic flow velocity data in the superior vena cava (SVC) and hepatic vein (HV) correlated well with the maximum tricuspid regurgitant signal area on the color Doppler echocardiogram, and systolic backward flow from the heart was more evident in the HV than in the SVC. In the SR group, however, no correlation was observed between the maximum systolic flow velocity and the TR signal area, and systolic backward flow was not evident even in cases with severe TR. 2. After open heart surgery, systolic flow velocities in the SVC and HV were significantly decreased in the SR group compared to the Af group. 3. There was close correlation between the presence of hepatomegaly and systolic backward flow towards the liver. Hepatomegaly was more marked in the Af group than in the SR group. 4. Jugular venous and hepatic pulse data correlated well with the flow velocity data in the SVC and HV and with the TR signal area. 5. Intensity of the tricuspid regurgitant murmur as estimated by the Levine's classification correlated relatively well with the systolic pressure gradient between the right ventricle and right atrium as calculated by the modified Bernoulli equation, but did not correlate with the TR signal area. From these results, we conclude that the intensity of the tricuspid regurgitant murmur and the jugular venous or hepatic pulse patterns are useful for evaluating tricuspid regurgitant dynamics, when they are applied clinically with precise recognition of their significance and limitations, and that sinus rhythm or atrial fibrillation is also an important factor.

Atrial Fibrillation↗
PubMed1990

[An analysis of ictal EEGs by a newly developed ambulatory cassette EEG system].

We evaluated the efficiency of a newly developed cassette EEG recording device and our system for detecting and analyzing ictal EEGs in epileptic children. We got 13 ictal records from 16 epileptic children. We could precisely differentiate and diagnose their classifications of seizures by comparative analyses of ictal records and clinical symptoms. We discussed the characteristics of our system, and described actual analysis methods in 3 cases as examples. It was concluded that our system offered valuable information about ictal events in epileptic children.

Adolescent↗
PubMed1990

[On the mechanisms of mitral regurgitation in rheumatic mitral valve disease: with special reference to the role of mitral valve prolapse].

To assess the role of mitral valve prolapse (MVP) in the pathogenesis of mitral regurgitation (MR) in rheumatic mitral valve disease (RMD), we performed phonocardiography (PCG), transthoracic and transesophageal two-dimensional and color Doppler (CD) echocardiography in 22 patients with RMD including three with pure mitral stenosis (MS), 11 with predominant MS, six with predominant MR and two with pure MR. Results were as follows: 1. Prolapse of the mitral valve (MV) was differentiated from systolic ballooning of the whole MV by the findings that the anterior leaflet's tip (rough zone) protruded into the left atrium with an acute angle between the body (clear zone) and rough zones of the anterior MV and that the posterior leaflet protruded markedly above the level of the mitral ring. 2. MR was detected in six patients (slight MR) by only the CD method and in 13 (mild, moderate or greater MR) by both the PCG and CD methods. 3. MR was absent or slight in five patients (three of pure MS and two of predominant MS) without valve thickening and with systolic ballooning of the whole valve due to commissural fusion. 4. Mitral valve abnormalities related to significant (mild, moderate or severe) MR were dependent on valve thickening (five patients), prolapse of the leaflet's tip toward the left atrium (four), or both (four). 5. An apical systolic click was found in only one of the nine patients with systolic ballooning, but in four of 11 with MVP. 6. The MR murmur in six of the nine patients with valve thickening showed the decrescendo or flat contour, but that in four of the eight patients with MVP showed a crescendo contour. From these results, we concluded that mitral valve prolapse should be considered as one of the important causes of mitral regurgitation in rheumatic mitral valve disease.

Adult↗
PubMed1989

[Studies on the pressor mechanism of 19-hydroxyandrostenedione].

In the present study, the pressor activity of 19-hydroxyandrostenedione (19-OH-AD) (which is a kind of androgen) and the presence or absence of the possibility of its role as an amplifier of mineralocorticoid were investigated. 34 Wistar rats of 8 weeks of age were used as the experimental subjects. The rats were divided into 3 groups, the control group (n = 12), 19-OH-AD group (n = 12) and DOCA group (n = 10). The control group was given 0.2 ml of sesame oil, the 19-OH-AD group was given 10 mg of 19-OH-AD dissolved in 0.2 ml of sesame oil, and the DOCA group was given 10 mg of DOCA dissolved in 0.2 ml of sesame oil. This was subcutaneously administered three times a week for 4 weeks, and body weight and blood pressure were observed. At the termination of the experiment, blood was sampled by decapitation, and the serum sodium concentration, erythrocyte sodium content, plasma renin activity (PRA), plasma atrial natriuretic hormone (alpha-rANP), and contents of DOC, corticosterone and aldosterone in adrenal gland were determined. The following results were obtained. The blood pressure at the termination of the experiment was higher than that at the initiation of the experiment by 9.9 +/- 1.9 (S.E.), 31.3 +/- 1.7, and 46.2 +/- 2.0 mmHg in the control, 19-OH-AD and DOCA groups, respectively, where significant elevations were observed in both the 19-OH-AD and DOCA groups as compared with the control group. As to the serum sodium concentration, only the DOCA group showed a significant elevation (p less than 0.001) as compared with the other two groups. However, the erythrocyte sodium contents of both the 19-OH-AD and DOCA groups increased significantly as compared with the control group. Moreover, the increase of the DOCA group was significantly higher (p less than 0.001) than that of the 19-OH-AD, and a significant positive correlation between the elevation of blood pressure and the erythrocyte sodium content was observed (p less than 0.001). As to the PRA value, only the DOCA group showed a significant lowering as compared with the other two groups, whereas alpha-rANP value of the DOCA group showed a significant elevation as compared with the other two groups. As to the contents of steroid hormones in the adrenal gland, all of the steroid hormones were significantly lower in the DOCA group, while those of the 19-OH-AD group were unchanged as were those of the control group.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenal Cortex Hormones↗
PubMed1989

Duchenne muscular dystrophy carriers. Proton spin-lattice relaxation times of skeletal muscles on magnetic resonance imaging.

By means of magnetic resonance imaging (MRI), the proton spin-lattice relaxation times (T1 values) of the skeletal muscles were measured in Duchenne muscular dystrophy (DMD) carriers and normal controls. The bound water fraction (BWF) was calculated form the T1 values obtained, according to the fast proton diffusion model. In the DMD carriers, T1 values of the gluteus maximus and quadriceps femoris muscles were significantly higher, and BWFs of these muscles were significantly lower, than in normal control. Degenerative muscular changes accompanied by interstitial edema were presumed responsible for this abnormality. No correlation was observed between the muscle T1 and serum creatine kinase values. The present study showed that MRI could be a useful method for studying the dynamic state of water in both normal and pathological skeletal muscles. Its possible utility for DMD carrier detection was discussed briefly.

Adult↗
PubMed1989

Role of the calcium-calmodulin system in the adenylate cyclase activity of vascular smooth muscle.

In order to evaluate the relationship between the calcium-calmodulin system and the adenylate cyclase activity of vascular smooth muscle, we examined the effects of several calcium effectors on the basal and stimulated adenylate cyclase activity. Thoracic aortae were removed from Wistar rats and the tissues were homogenated with cold homogenizing buffer containing 1 nM EDTA. Membrane protein fraction of the smooth muscle was prepared by centrifugation at 37,000 g. In this procedure, endogenous guanine nucleotides and contractile proteins remained. The protein fraction was incubated with 2 mM EGTA, 50 microM trifluoperazine, 0.1 microM A23187 or 25 microM calmodulin under basal and stimulated (50 microM isoproterenol, 100 microM GTP and 50 microM forskolin) conditions. The adenylate cyclase activity was determined by a method modified in our laboratory using double isotope counting. Trifluoperazine reduced the basal adenylate cyclase activity significantly (p less than 0.01) as well as the stimulated enzyme activities. A23187 did not affect the basal enzyme activity, but elevated the isoproterenol stimulated enzyme activity significantly (p less than 0.05). EGTA did not affect the basal and stimulated adenylate cyclase activities. Calmodulin elevated the basal enzyme activity significantly (p less than 0.02), but did not affect the stimulated enzyme activities. These results suggest that the calcium-calmodulin system is necessary for maintenance of the adenylate cyclase activity of vascular smooth muscle cells. The calmodulin acting site is considered to be the catalytic subunit, and stimulation of the enzyme is accelerated by calcium ion.

Adenylyl Cyclases↗
PubMed1989

Pharmacologic characterization of a novel non-benzodiazepine selective anxiolytic, DN-2327.

DN-2327, 2-(7-chloro-1,8-naphthyridin-2-yl)-3-[(1,4-dioxa-8- azaspiro[4.5]dec-8-yl)carbonylmethyl]isoindolin-1-one, produced anxiolytic, taming and anti-convulsive effects when administered orally to several species of animals. DN-2327 produced few of the sedative-hypnotic and muscle-relaxant effects observed with diazepam. The durations of the anxiolytic and anti-convulsive activities of DN-2327 were much longer than those of diazepam. Tolerance to DN-2327 did not develop when it was administered daily for 14 days in an anti-conflict test (Vogel conflict test). DN-2327 showed potent displacement activity against [3H]diazepam binding. The binding affinity of DN-2327 for benzodiazepine receptors was about twenty times that of diazepam. Furthermore, the affinity of DN-2327 for benzodiazepine receptors was not enhanced by the presence of GABA. There is a wide margin between the doses of DN-2327 that cause the anxiolytic effects and its sedative-hypnotic/muscle-relaxant effects. These results suggest that DN-2327 has more marked anxioselective properties compared with the benzodiazepines.

Aggression↗
PubMed1989

[Innervation of the mitral valve in normal and prolapsed mitral valves].

To evaluate the relationship between mitral valve prolapse (MVP) and autonomic nerve dysfunction, clinical and immunohistochemical studies were performed. I. Clinical study Autonomic function tests and supine bicycle exercise were performed in 60 patients with MVP, 41 under 35 years of age and 19 of 35 years and older, and the results were compared with those of 31 normal controls, 19 under 35 years of age and 12 of 35 years and older. Case with positive response on postural stress and cold pressor tests were more frequent in both MVP groups than those of controls. Plasma nor-adrenaline levels were higher in the MVP groups than in the control groups during exercise. Our clinical observation suggested that autonomic dysfunction, particularly sympathetic hyperactivity, probably is present in MVP irrespective of age. II. Immunohistochemical study In 23 mitral valves (15 of normal controls and eight of MVP), three normal tricuspid, three normal aortic and three normal pulmonic valves, immunohistochemical localizations of S-100 protein, glial fibrillary acidic protein (GFAP) and neurofilament protein (NFP) were examined to detect the distribution of all nerve endings, choline acetyltransferase (ChAT) to detect the distribution of cholinergic nerve fibers, and neuropeptide Y (NPY) and calcitonin gene related peptide (CGRP) to detect the distribution of afferent nerve fibers, using the avidin-biotin peroxidase complex (ABC) method. The distribution of adrenergic nerve fibers was examined by fluorescence with the glyoxylic acid method. In normal valves, S-100 protein was mainly demonstrated in the base and body of the valve cusp. It was very scanty in the tip, and was only found in the coaptation zone that is, the layer of the atrialis or along the boundary between the atrialis and the spongiosa in the atrioventricular valves. The distribution of S-100 protein in the prolapsed mitral valve was the same as that of the normal valve except for the lack of S-100 protein in the degenerated portion. The distribution of GFAP, NFP, ChAT, NPY, CGRP and adrenergic fluorescence were the same as that of S-100 protein in both the normal and prolapsed mitral valves. It is suggested that the above-mentioned anatomical distribution of the nerve in the mitral valve is closely related to the dysfunction of the autonomic nerve system in the condition of mitral valve prolapse, because the body of the mitral valve is rich in nerve endings and this area is most easily influenced by the mechanical stimulation due to abnormal coaptation.

Adult↗
PubMed1989

[Assessment of prolapsing pattern of the anterior mitral valve in mitral valve prolapse: new echocardiographic diagnostic criteria].

In the present study, the ballooning pattern of the anterior mitral valve (AMV) in mitral valve prolapse (MVP) was investigated, and new diagnostic criteria for MVP were established using two-dimensional and Doppler echocardiography. The study population consisted of 164 patients with prolapse of the AMV alone, including 86 patients with idiopathic MVP, 52 associated with atrial septal defect (ASD), 17 having chordal rupture and nine associated with connective tissue disorders. There were 60 normal controls. The results were as follows: 1. The AMV was divided into two zones, clear and rough (CZ and RZ), according to the point of insertion of the strut chordae based on two-dimensional long-axis echocardiograms of the left ventricle. The severity of AMV prolapse was determined by an angle between the posterior aortic wall (PAO)-CZ and the CZ-RZ. a) Type A: Apparently there was a transitional point between CZ and RZ, despite normal PAO-CZ and CZ-RZ angles. The RZ showed mild ballooning or prolapse into the left atrium. b) Type B: Although the PAO-CZ angle was normal, the CZ-RZ angle was markedly narrowed. Therefore, prolapse of the RZ was more severe compared with that of type A. c) Type C: An overall zone of the AMV showed ballooning or prolapse into the left atrium due to a narrowed PAO-CZ angle. 2. Type B prolapse was frequently observed in idiopathic MVP (58%), the ASD group (71%) and the chordal rupture group (71%), and type C prolapse in MVP of connective tissue disorders (89%). 3. All of 18 patients (100%) with type A, 48 of 99 (48%) with type B, and 10 of 47 (21%) with type C could not be diagnosed as MVP using Gilbert's criterion. 4. Doppler mitral regurgitation (MR) was detected in 40 of the 47 patients (85%) with type C in 56 of the 99 (59%) with type B, and in seven of the 18 (39%) with type A. These results suggested that classification of the two-dimensional echocardiography of the AMV into two zones, clear and rough (CZ and RZ), could contribute to determining not only the severity of AMV prolapse, but also to the extent of myxomatous changes of the AMV and to evaluating the correlations between the degree of MVP and the incidence of MR.

Adolescent↗
PubMed1989

[A case of mitral valve prolapse simulating mitral tumor or vegetation].

We observed a case of mitral valve prolapse (MVP) mimicking mitral tumor or vegetation. The patient was a 34-year-old man. He complained of palpitation and precordial oppression. Shaggy and mass echoes of the anterior mitral valve were recorded by M-mode and two-dimensional echocardiograms. The "mass" echo was confirmed to by originated in a markedly myxomatous change of the spongiosa layer of the mitral valve at operation. These problems on echocardiographic diagnosis of MVP and mitral "mass", such as mitral tumor or vegetation, were discussed in detail.

Adult↗
PubMed1989

Measurement of regional myocardial blood flow in hypertrophic cardiomyopathy: application of the first-pass flow model using [13N]ammonia and PET.

Positron emission tomography (PET) has become an important tool in the study of regional myocardial blood flow. The purpose of the present study was to measure regional myocardial blood flow using dynamic [13N]ammonia PET and the first-pass flow model. Thirteen patients with hypertrophic cardiomyopathy, and with a considerably thickened ventricular wall (25 mm or greater), were selected for the study in order to minimize errors due to spillover of radioactivity from blood to the myocardium and to the underestimation of myocardial activity caused by the partial volume effect. Arterial input function was determined by assigning a region of interest to the left atrial cavity on the PET images. Using left atrial and myocardial time-activity curves, regional myocardial blood flow was calculated using the first-pass flow model. Mean myocardial blood flow ranged from 47.8 to 76.5 ml/min per 100 g (63.0 +/- 9.4). Regional myocardial blood flow in the septum was significantly lower than in the anterior and lateral walls of the left ventricle (P less than .01). These results indicate the potential usefulness of dynamic PET in the measurement of regional myocardial blood flow in man.

Adult↗
PubMed1989

[Two-dimensional and Doppler echocardiographic studies of the genesis of a high-pitched diastolic rumble in mitral stenosis: contribution of the deformed mitral orifice and eccentric mitral inflow jet].

To clarify the genesis of a high-pitched diastolic rumble in mitral stenosis, 51 patients with mitral stenosis were studied. They were subdivided into two groups based on the pitch of a rumble; six patients with a high-pitched rumble and 45 patients with an ordinary low-pitched rumble. Phonocardiography, and M-mode and two-dimensional (2-D) echocardiography were performed in all patients. Color and continuous wave Doppler echocardiography were performed in four patients with a high-pitched rumble and in 13 with a low-pitched rumble. Results obtained were as follows: 1. Points of the maximum intensity of a rumble: A low-pitched rumble was best heard at the apex in all patients. A high-pitched rumble was best heard at the mesoapical area, except in one patient who had an oval mitral orifice by 2-D echocardiography. 2. Correlation between the pitch of rumble and the shape of the mitral orifice: In five of the six patients with a high-pitched rumble, the mitral orifice had a tadpole-shaped deformity, in which commissural fusion and valvular thickening were more marked anterolaterally than posteromedially. Among 45 patients with oval, slit or pinhole-like valve orifices, only one had a high-pitched rumble. 3. Direction of the left ventricular (LV) inflow jet as observed by color Doppler echocardiography: On the short-axis view at the level of the papillary muscles, the inflow jet was directed toward the medial portion of the LV cavity in the patients with a high-pitched rumble. However, it was directed towards the central portion of the LV cavity in all patients with a low-pitched rumble. On the apical long-axis view, no distinct difference was detected in the direction of the LV inflow jet between the two groups. 4. Other findings: There were no significant differences between the two groups in the mitral orifice area, the peak velocity of LV inflow, fractional shortening of the LV, dimension of the left atrium, Wells' index and the degree of organic change in the subvalvular structures. These results suggest that the deformity of the mitral valve and resultant changes in the direction of the LV inflow jet may play an important role in the mechanism of producing a high-pitched diastolic rumble in mitral stenosis.

Adult↗
PubMed1988

Proton spin-lattice relaxation time of Duchenne dystrophy skeletal muscle by magnetic resonance imaging.

By means of proton MRI, the spin-lattice relaxation times (T1 values) of pelvic and leg muscles were measured in Duchenne muscular dystrophy (DMD) patients and normal controls. The bound water fraction (BWF) was calculated from the T1 value obtained. In normal children, the T1 value decreased, and BWF increased with age. In DMD, the T1 value rapidly decreased, from an abnormally high value in the early stages, with the progress of the disease. This reduction of the T1 value in DMD was not the same for all muscles; it was most prominent in the gluteus maximus and least prominent in the sartorius and gracilis muscles. BWF was below normal in the early stages of DMD. It is suggested that both regenerating and degenerating muscle fibers, together with the increased muscle water content, cause the high T1 value and low BWF in the early stages of DMD, whereas replacement of muscle by fat causes the decreased T1 value in the advanced stages.

Child↗
PubMed1988

Role of calcium ion in acth-induced steroidogenesis in humans.

In order to examine the role of calcium ion in ACTH-induced steroidogenesis in humans, we carried out infusion of a pharmacological dose of ACTH (4.2 micrograms/kg) and a physiological dose of ACTH (0.0084 microgram/kg) for 120 min, and infusion of dibutyryl cyclic AMP (DBcAMP) [0.33 mg/kg/min] for 20 min, in 22 normal subjects with or without verapamil treatment (360 mg/day, orally) for 5 days. The subjects were pretreated with 1.0 mg of dexamethasone and 5.0 mg of enalapril daily for 2 days before each infusion test to inhibit endogenous ACTH and angiotensin II. Following infusion of 0.0084 microgram/kg of ACTH, plasma levels of corticosterone (P less than 0.02) and cortisol (P less than 0.01) were significantly increased; with chronic verapamil treatment plasma levels of corticosterone (P less than 0.05) and cortisol (P less than 0.02) were significantly lower than those without verapamil. On the other hand, 4.2 micrograms/kg of ACTH for 120 min significantly increased the plasma levels of several steroid hormones, although there were no differences between the infusion with and without verapamil. Infusion of DBcAMP for 20 min significantly increased plasma levels of corticosterone (P less than 0.02) and cortisol (P less than 0.01), but verapamil did not affect the steroidogenic response to the DBcAMP infusion. The present results suggest that steroidogenesis induced by a physiological dose of ACTH differs from that after a pharmacological dose of ACTH or DBcAMP, and is mediated mainly by calcium ion as an intracellular messenger in man.

Adrenal Cortex Hormones↗