Biomedical subjects

K Shizuka

Publications and source records attributed to K Shizuka.

5 recordsLinked to original sources

PubMed2001

[Relationship between depression and lipid metabolism in the elderly with hypertension].

In order to examine the relationship between depressive symptoms and the lipid metabolism in the elderly with hypertension, we recruited 311 outpatients aged 65 or older with hypertension and defined depression as patients with 6 or more symptoms on Geriatric Depression Scale short form. We further classified depressed patients into three groups: mild depressed with 6-7 symptoms, moderate depressed with 8-10 symptoms and severe depressed with 11 or more symptoms. Serum total cholesterol, serum HDL cholesterol and serum LDL cholesterol levels were significantly higher in female depressed patients than those in nondepressed patients (TC, 194.6 +/- 30.1 vs 208.0 +/- 32.8 p < 0.01; HDL, 67.3 +/- 19.3 vs 72.3 +/- 16.2 p < 0.01; LDL, 107.6 +/- 26.5 vs 116.0 +/- 29.1 p < 0.05). In male patients, serum lipids were not significantly associated with depressive symptoms but depressed patients were significantly older than nondepressed patients (75.3 +/- 6.2 vs 78.0 +/- 5.9 p < 0.05). Concerning the analysis of the severity of depression, serum total cholesterol and serum LDL cholesterol levels were significantly higher in mildly depressed patients than nondepressed patients in females and the same tendency was seen in male patients. No linear associations were shown between the severity of depression and serum lipids. We concluded that hyperlipidemia may be associated with depressive symptoms in elder patients with hypertension and that it might be related the severity of depression. We need to further investigate the relationship between depression and lipid metabolism in larger population samples.

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PubMed2000

[Type A behaviour pattern and hypercholesterolemia in elder patients].

To examine the relationship between type A behavior pattern and hypercholesterolemia, we recruited 109 primary hypercholesterolemic patients without treatment for hyperlipidemia (30 males and 79 females) and then classified them according to Maeda's questionnaire into two groups; type A group (16 males and 35 females, aged 73.1 +/- 8.7) and type B group (14 males and 44 females, aged 71.3 +/- 8.7). We studied serum total cholesterol, serum triglyceride and BMI. Serum total cholesterol was shown significantly higher in type A group than that in type B (233.0 +/- 22.8 vs 223.9 +/- 14.2 p < 0.01) and BMI lower (24.0 +/- 3.9 vs 25.4 +/- 3.9 p < 0.05), however, there was no significant difference in serum triglyceride between two groups (148.96 +/- 8.2 vs 134.0 +/- 48.8). Although there was no significant difference in BMI, serum total cholesterol was significantly higher in the women's group and in the 60s. This study suggests that type A behavior pattern is related to lipid metabolism, however we should take gender and age into consideration to study the relationship between type A behavior pattern and lipid metabolism.

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PubMed1998

Control of the pulmonary arterial resistance by the use of the oscillated assist flow.

In the clinical application of supporting circulation, the treatment of a patient with pulmonary hypertension is very important. We developed the electromagnetically driven vibrating flow pump (VFP) as a totally implantable type ventricular assist system. The artificial heart driven by electromagnetic forces creates high speed oscillation flow around 10-50 Hz. Assistance by high-speed oscillation flow has an interesting influence on the cardiovascular system. In this study, we carried out research on the influence such oscillation flow had on the pulmonary arterial vessels, and the supporting flow wave-form that controlled pulmonary vascular resistance was considered. Six healthy adult goats of both sexes were used in the experiments. We carried out inhalation anesthesia and performed intubation. The thorax was opened through left fourth rib resection. Right heart bypass was performed from the right atrium to the pulmonary artery. The flow of right heart assistance was maintained within 20-25% of total flow. Our purpose was to add flow of a specific high frequency to the right heart circulation. The hemodynamic parameters were recorded on a magnetic tape data recorder and input into a computer through an A-D converter. A result identified was that the pulmonary vascular resistance changed according to the alteration of the driving frequency of the VFP even during the same flow assistance. The resistance of the pulmonary arterial vessels became smaller when the driving of the VFP of 30 Hz was added to the right heart circulation. This was significant even when compared with continuous flow right heart assist. The characteristics of impedance appeared to have interesting alterations as well. Control of pulmonary vascular resistance by right heart assistance becomes possible if these results are applied. Accordingly, it may become one of the choices for treatment of a patient with pulmonary hypertension.

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PubMed1998

Development of vibrating flow pump for left ventricular assist circulation.

Vibrating flow pump (VFP) can generate high frequency oscillated blood flow within 10-40 Hz. In this study, new type VFP was developed as a ventricular assist device. Left Ventricular assist circulation using VFP were performed as aseptic animal experiments using goats. hemodynamic parameters were recorded continuously at awake state. Driving frequency of VFP was 25 Hz and pump flow rate was controlled to approximately 2 l/min. Frequency of VFP was 25 hz and pump flow rate was controlled to approximately 2 L/min. Frequency analysis method was used for analyzing hemodynamics. The peak of power was observed at 25 Hz from the Fourier transformation of blood flow waveform. Systemic vascular resistance was decreased by the start of left ventricular assistance using oscillated blood flow. No fatal arrhythmia was observed during this study. As the conclusion, new type VFP has a sufficient performance for left ventricular assistance. Small size blood pump may be enabled by the oscillated blood flow because VFP is driven at high frequency moving with short stroke volume.

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PubMed1997

Pulmonary arterial impedance analysis by the use of the oscillated assist flow.

Pulmonary arterial impedance is an important and interesting characteristic that can be used to evaluate the physiological properties of the pulmonary vessel. However, power spectrum analysis of the pulmonary artery pressure and flow pattern have suggested that peak power in the relatively high frequency range (> 10 Hz) is significantly low; thus, we cannot analyze the vessel properties in the high frequency range. In this study, we used the newly developed vibrating flow pump (VFP), which can generate oscillated blood flow with a relatively high frequency (10-50 Hz) for right heart bypass, to evaluate the pulmonary arterial impedance pattern in the high frequency range. Acute animal experiments of the right heart bypass from the right atrium to the pulmonary artery using 6 healthy adult goats were performed. The flow pattern and pressure of the pulmonary artery, electrocardiograms (ECGs), and arterial and right atrial pressures were continuously monitored during the experiments. Spectral analysis of the hemodynamic parameters using the fast Fourier transform (FFT) method was performed to evaluate the spectral properties. The coherence function, transfer function, and phase patterns were calculated to analyze the impedance pattern in the relatively high frequency area. Previously, various investigators had tried to analyze the impedance patterns of the pulmonary artery; however, they could not analyze the impedance patterns over 10 Hz because the spectral patterns of the pulmonary flow do not have high power at high frequencies. These physiological analyses may be useful in designing the optimal pulmonary circulation.

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