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Biomedical subjects

N Fukuda

Publications and source records attributed to N Fukuda.

At least 325 records · Page 18Linked to original sources
PubMed1984

[Noninvasive studies of dynamic left ventricular outflow obstruction in patients with sigmoid septum].

In order to evaluate the clinical significance of the markedly protruding interventricular septum into the left ventricular (LV) cavity (sigmoid septum), we performed non-invasive studies including amyl nitrite (AN) inhalation in 21 patients (pts) with two-dimensional echocardiographic (2DE) documentations. LV outflow tract (LVOT) obstruction was determined by the presence at least three of the following findings at rest or during AN inhalation: 1) a loud apical ejection systolic murmur (ESM), 2) a midsystolic dip in the carotid pulse, 3) systolic anterior motion (SAM) of the mitral valve (MV) or chordae tendineae, and 4) systolic semiclosure of the aortic valve (AV). The 21 pts were subdivided into six pts (group I) with resting (two pts) or provocative (four) obstruction, and 15 pts (group II) without obstruction. Their ages ranged from 40 to 85 years with an average of 65. No pt had evidence of hypertrophic cardiomyopathy. Results were as follows: In five pts of group I a long ESM with a mid-systolic peak was recorded near the apex. After AN inhalation, this murmur was markedly intensified. On the contrary, all pts of group II had a short and early systolic murmur, which was not markedly intensified by AN. In contrast to group II, group I pts had a significantly smaller LV end-diastolic dimension, a smaller LVOT dimension, higher percent thickening of the LV posterior wall, higher fractional shortening and decreased aorto septal angle (the angle between the anterior aortic wall and the interventricular septum by 2DE). On 2DE, each pt of group I showed significant narrowing between the protruded septum and the hypercontractile LV posterior wall with the papillary muscle. Anteriorly shifted chordae tendineae noted as the SAM on the M-mode echocardiogram might also play an important role on the genesis of obstruction. The signs of LVOT obstruction at rest disappeared following oral administration of propranolol in two pts of group I. These observations suggested that LVOT obstruction might occur in some pts with sigmoid septum and the hypercontractile state, and that a systolic murmur observed in this condition should be differentiated from a functional murmur in the aged or a systolic murmur in hypertrophic obstructive cardiomyopathy.

Adult↗
PubMed1984

Interactions between fatty acid synthesis, oxidation, and esterification in the production of triglyceride-rich lipoproteins by the liver.

In a series of experiments with male rat livers perfused with or without 5-tetradecyloxy-2-furoic acid (TOFA) in the presence and absence of oleate, the relationships between fatty acid synthesis, oxidation, and esterification from newly synthesized and exogenous fatty acid substrates have been examined. When livers from fed rats were perfused without exogenous fatty acid substrate, 20% of the triglyceride secreted was derived from de novo fatty acid synthesis. Addition of TOFA caused immediate and nearly complete inhibition of fatty acid synthesis, measured by incorporation of 3H2O into fatty acids. Concurrently, ketone body production increased 140% and triglyceride secretion decreased 84%. These marked reciprocal alterations in fatty acid synthesis and oxidation in the liver almost completely abolished the production of very low density lipoproteins (VLDL). Cholesterol synthesis was also depressed by TOFA, suggesting that this drug also inhibited lipid synthesis at a site other than acetyl-CoA carboxylase. When livers from fed rats were supplied with a continuous infusion of [1-14C]oleate as exogenous substrate, similar proportions, about 45-47%, of both ketone bodies and triglyceride in the perfusate were derived from the infused [1-14C]oleate. The production of ketone bodies was markedly increased by TOFA; the secretion of triglyceride and cholesterol were decreased. Altered conversion of [1-14C]oleate into these products occurred in parallel. While TOFA decreased esterification of oleate into triglyceride, incorporation of [1-14C]oleate into liver phospholipid was increased, indicating that TOFA also affected glycerolipid synthesis at the stage of diglyceride processing. The decreased secretion of triglyceride and cholesterol following TOFA treatment was localized almost exclusively in VLDL. The specific activities of 3H and of 14C fatty acids in triglyceride of the perfusate were greater than those of liver triglyceride, indicating preferential secretion of triglyceride produced from both de novo fatty acid synthesis and from infused free fatty acid substrate. These observations suggest the following chain of events in the liver following TOFA treatment: inhibition of fatty acid and cholesterol synthesis; increased fatty acid oxidation and ketogenesis; decreased triglyceride synthesis as a result of inhibition of fatty acid synthesis, stimulation of fatty acid oxidation, and altered partition of diglyceride between triglyceride and phospholipid synthesis; and decreased production of VLDL. These comparative rat liver perfusion experiments indicate that free fatty acids provide the major source of substrate for the hepatic production of triglyceri

Animals↗
PubMed1984

[Mechanism of an early diastolic posterior motion of the interventricular septum in patients with mitral stenosis: with special reference to left ventricular inflow velocity pattern].

The mechanism of an early diastolic posterior motion of the interventricular septum (IVS) was investigated by means of M-mode, two-dimensional and pulsed Doppler echocardiographies in 53 patients with pure mitral stenosis (MS). Velocity patterns of the blood flow at the inflow tract of the left ventricle (LVIT) were classified into three types as previously reported (cf. Fig.3). The results obtained were as follows: The mitral valve orifice area (MVA) was significantly smaller in patients with type III of the LVIT flow velocity pattern than in patients with type I (p less than 0.001). An amplitude ("a") of the posterior IVS motion in systole (P1) was significantly diminished in type III (4.2 +/- 1.1 mm) than in type I (6.6 +/- 1.5 mm) (p less than 0.001). An amplitude ("b") of the posterior IVS motion in early diastole (P3) showed a significant increase in type III (7.5 +/- 1.2 mm) than in type I (5.2 +/- 1.5 mm) (p less than 0.001). Difference of the amplitude between P1 and P3 ("a-b") was significantly greater in type III (-3.4 +/- 1.1 mm) than in type I (1.4 +/- 0.9 mm) (p less than 0.0001). MVA was correlated statistically with "a" (r = 0.58, p less than 0.001), "b" (r = -0.38, p less than 0.01) and "a-b" (r = 0.80, p less than 0.0001). Deformity of the left ventricular cavity due to the flattened IVS in early diastole was observed in severe MS with an augmented septal P3 dip. A case of severe MS with type III velocity pattern and an augmented P3 dip showed type II velocity pattern and a decreased P3 dip after the attack of acute myocardial infarction. These findings suggested a close relationship between type III of the LVIT flow velocity pattern and the prominent septal P3 dip. The importance of diastolic suction of the left ventricle in producing an early diastolic posterior motion of IVS (P3) was discussed.

Biomechanical Phenomena↗
PubMed1984

[Left ventricular function in patients with right ventricular overload evaluated by exercise echocardiography: comparison of pulmonary hypertension and atrial septal defects].

To evaluate left ventricular function in patients (pts) with right ventricular overload, exercise echocardiographic studies using a bicycle ergometer were performed for seven pts with pulmonary hypertension (PH), two with cor pulmonale (CP) and 16 with atrial septal defects (ASD), and the results were compared with those of 10 (control I) and 27 (control II) normal persons. These subjects were categorized in two study groups; study I consisting of PH, CP and control group I with an exercise workload of 25 watts for 3 min; and study II consisting of ASD and control group II with an exercise workload of 50 watts for 3 min. The results were as follows: M-mode echocardiography revealed that: During exercise, the stroke volume (SV) was increased with a significant decrease of left ventricular end-systolic dimension (LVDs), but without a change in left ventricular end-diastolic dimension (LVDd) in control groups I and II, with a marked increase of LVDd and a slight decrease of LVDs in the ASD group. By contrast, the SV in the PH group tended to decrease during exercise with a slight decrease of LVDd, but without a significant change in LVDs. Right ventricular dimension (RVD) was significantly increased during exercise in the PH group, but was decreased in the ASD group. In control groups I and II, RVD did not change during exercise. In ASD, and control groups I and II, the peak velocity of circumferential fiber shortening (Vcf) was increased during exercise, and the peak negative Vcf was significantly decreased. However, these parameters exhibited impaired responses during exercise in the PH group. Abnormal interventricular septal (IVS) motion at rest tended to become normal during exercise in 12 of 16 pts with ASD. In all pts with PH, however, IVS motion did not change substantially during exercise. There were similar parameter responses between the PH and CP groups. Two-dimensional echocardiography showed that: The left ventricular short-axis view demonstrated a diastolic left ventricular configuration which changed from oblique to relatively circular orientation during exercise in the ASD group. In four of five pts with PH, the diastolic configuration of the left ventricle was oblique because of a loss of the normal curvature of the IVS at rest and during exercise. The diastolic left ventricular configuration improved during exercise in only one pt with PH, with slightly elevated pulmonary arterial systolic pressure as in the ASD group.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1984

[Left ventricular diastolic filling patterns in hypertrophic cardiomyopathy and myocardial infarction: studies by pulsed doppler echocardiography and multi-gated blood pool scans].

Relationship between various parameters of the left ventricular inflow velocity patterns by pulsed Doppler echocardiography and the early diastolic mean filling rate (V1) by multi-gated blood pool scans was evaluated. The materials consist of 26 patients with hypertrophic cardiomyopathy (HCM), 24 with old myocardial infarction (MI), seven with hypertensive heart disease (HHD), seven with dilated cardiomyopathy (DCM), seven with ischemic heart disease (IHD), and 16 normal subjects (N). The results were as follows: 1. Acceleration time (AT) and deceleration time (DT) were significantly prolonged in HCM (120 +/- 20 msec, 147 +/- 23 msec), MI (102 +/- 17 msec, 124 +/- 21 msec), HHD (105 +/- 11 msec, 141 +/- 17 msec) and IHD (111 +/- 16 msec, 122 +/- 20 msec) compared with those of normals (89 +/- 20 msec, 106 +/- 18 msec). 2. V1 was significantly decreased in HCM (1.14 +/- 0.28 sec-1), MI (0.68 +/- 0.24 sec-1), HHD (0.73 +/- 0.12 sec-1), DCM (0.67 +/- 0.30 sec-1) and IHD (1.03 +/- 0.29 sec-1) compared with that of normals (1.48 +/- 0.28 sec-1). 3. There were significant negative correlations between V1 and AT or DT in HCM, IHD with slightly impaired diastolic filling and normals. However, there were significant positive correlations between V1 and AT or DT in MI and DCM. These findings suggested that left ventricular diastolic filling is impaired in both HCM and MI, and that DT-V1 relationship is useful for differentiating HCM characterized by the "chamber stiffness" from MI characterized by the "myocardial stiffness".

Adolescent↗
PubMed1984

[Phono- and echocardiographic studies of the genesis of mitral valve prolapse in patients with funnel chest].

Two-dimensional echocardiograms (2-DE) and phonocardiograms (PCG) were used to clarify the genesis of mitral valve prolapse (MVP) and mitral regurgitation (MR) in 44 patients with funnel chest. These patients were categorized in three groups on the basis of the fronto-sagittal index (FSI) as determined from chest radiographs; 17 as mild, 15 as moderate and 12 as severe funnel chest. Their ages ranged from 5 to 65 years and averaged 24 years. MVP was diagnosed using the long-axis view of the 2-DE, and MR was diagnosed phonocardiographically including provocative test using angiotensin II. The results were as follows: In 44 patients with funnel chest, 20 (45%) had MVP and 15 (34%) had MR, respectively. The incidence of MVP increased directly in proportion to the severity of index, but the incidence of MR did not. In the short-axis view of the left ventricle at the level of the papillary muscles, there was more marked flattening of the interventricular septum than of the left ventricular posterior wall, resulting in deformity of the left ventricular geometry. A distortion index (DI) was used to quantify the degree of distortion of left ventricular shape, calculated as follows: DI = (R-r)/r, where R and r were radii of the curvatures of the interventricular septum and the left ventricular posterior wall, respectively. The DI in end-diastole (DId) and end-systole (DIs) increased in proportion to the severity of funnel chest. Patients were subdivided into four groups on the basis of DId. Incidence of MVP increased in proportion to the degree of distortion of the left ventricular shape. There was, however, no significant difference in the incidence of MR among the four groups. Patients were subdivided; one group of 13 under 14 years of age; another, 31 over 15 years old. The incidence was much higher in the latter than the former, but the incidence of MVP increased in proportion to the severity of funnel chest in both groups. MR was complicated by MR in nearly all cases in the latter group, but none had MR in the former. The DI of patients, whose FSI improved with surgery, apparently improved in addition to the disappearance and/or improvement of their MVP and MR. However, patients whose FSI did not improve with surgery showed little change in DI and persistence of MVP and/or MR.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1984

Independent effect of a mixed-beam regimen of fast neutrons and gamma rays on a murine fibrosarcoma.

Biological effectiveness of a mixed-beam regimen of fast neutrons and photons was studied in an animal tumor system. NFSa , a spontaneous fibrosarcoma in a C3H mouse, was transplanted in the right hind legs of syngeneic male mice and locally irradiated with a single dose or five daily doses. Tumor control experiments showed that five gamma-ray doses increased TCD50 values by 20 Gy and produced a shallower slope on the dose-response curve compared to that after a single fraction. Fractionated neutron doses also increased the TCD50 value by 9 Gy without changing the slope of the dose-response curve. A mixed-beam regimen of N-gamma-gamma-gamma-N resulted in an independent effect on the tumor. Second, tumor cell survival was examined by the lung colony assay. Nembutal anesthesia reduced the tumor oxic cell fraction, resulting in a single component dose-response curve after a single gamma ray. Five fractionated doses of gamma rays increased both D0 and extrapolation number while those of fast neutrons increased only extrapolation number. The D0 and extrapolation number of the mixed-beam regimen were again identical to those values assuming that the mixed-beam effect was independent. RBEs obtained from cell survival were fairly close to those from TCD50 assays except single-dose experiments.

Animals↗
PubMed1984

Studies on the mechanism of hypertriglyceridemia in the genetically obese Zucker rat.

The possibility that impaired removal of lipoprotein triglyceride from the circulation may be a participating factor in the hypertriglyceridemia of the obese Zucker rat was examined. We found no significant differences in the heparin-released lipoprotein lipase (LPL) activities of the adipose tissue, skeletal muscle, and heart (expressed per gram of tissue) from the lean and obese Zucker rats. Furthermore, the kinetic properties of adipose tissue and heart LPL from the lean and obese rats were similar, indicating that the catalytic efficiency of the enzyme was unaltered in the obese animals. The postheparin plasma LPL activities of lean and obese rats were also similar. However, the postheparin plasma hepatic triglyceride lipase (H-TGL) activity in the obese rats was elevated. The higher activity of H-TGL could not alleviate the hypertriglyceridemia in these animals. Since hypertriglyceridemia in the obese rats could also be due to the hepatic production of triglyceride-rich lipoproteins which are resistant to lipolysis, we therefore isolated very low density lipoproteins (VLDL) from lean and obese rat liver perfusates and examined their degradation by highly purified human milk LPL. Although certain differences were observed in hepatic VLDL triglyceride fatty acid composition, the kinetic patterns of LPL-catalyzed triglyceride disappearance from lean and obese rat liver perfusate VLDL were similar. The isolated liver perfusate VLDL contained sufficient apolipoprotein C-II for maximum lipolysis. These results indicate that impaired lipolysis is not a contributing factor in the genesis of hypertriglyceridemia in the genetically obese Zucker rat. The hyperlipemic state may be attributed to hypersecretion of hepatic VLDL and consequent saturation of the lipolytic removal of triglyceride-rich lipoproteins from the circulation.

Adipose Tissue↗