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Biomedical subjects

T Shiina

Publications and source records attributed to T Shiina.

At least 109 records · Page 6Linked to original sources
PubMed1989

Inter-relationship between urinary kallikrein-kinins and arginine vasopressin in man.

1. Physiological saline solution was infused in nine normal subjects and six patients with central diabetes insipidus (DI). At 120 min after the start of infusion, arginine vasopressin (AVP) was injected intramuscularly. Urine was collected in 30 min fractions before and after AVP administration. 2. The urinary excretions of kallikrein-like activity (KAL-A) (S-2266 hydrolysis activity) and immunoreactive kinins (i-kinins) were significantly lower in patients with DI than in normal subjects before AVP administration, while there were no differences in plasma renin activity, plasma aldosterone concentration, creatinine clearance and blood pressure between the two groups, except for a marked water diuresis in patients with DI. The urinary excretion of KAL-A and i-kinins correlated positively with the urinary excretion of AVP. 3. AVP administration increased both plasma AVP and urinary excretion of AVP to similar levels in both groups. As a result, urine volume decreased to a greater degree in patients with DI than in normal subjects. In contrast, the urinary excretions of KAL-A and i-kinins were increased by AVP administration, with a greater response in normal subjects than in the patients with DI. 4. After overnight fasting, acute water loading was carried out orally for 15 min in six normal subjects. At 30 min plasma AVP was suppressed by water loading to almost the basal level found in patients with DI. Urinary excretions of KAL-A and i-kinins in the first 30 min fraction after loading were also suppressed to the basal level in patients with DI. Later, the urinary excretion of KAL-A increased together with the increase in urine flow. Urine volume and free water clearance markedly increased except in the first 30 min fraction, compared with the control period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Possible involvement of cyclic GMP (cGMP) in atrial natriuretic factor (ANF) induced natriuresis].

In order to clarify the mechanism of action of ANF on nephron, nephrogenous cGMP (NcGMP) was calculated. And the interrelationship between the changes in NcGMP, urinary sodium excretions or renal hemodynamics were investigated with direct intrarenal infusion of various doses of ANF. A small dose of ANF (0.03 micrograms/kg/min) increased sodium clearance (CNa) significantly without any appreciable changes in NcGMP, creatinine clearance (Ccr) or renal blood flow (RBF). A larger dose of ANF (0.1 or 0.3 micrograms/kg/min) significantly increased CNa, NcGMP, RBF and Ccr. A net increase in CNa (delta CNa) had a positive correlation with that in NcGMP (delta NcGMP), but the regression line did not pass through the zero point. These findings imply that a larger dose of ANF might effect on glomeruli and gene-rate cGMP to induce natriuresis by raising GFR. However natriuresis induces by a small dose of ANF considered to be caused by the other mechanisms, possibly by the direct or indirect effect of ANF on renal tubules.

Animals↗
PubMed1989

[Basic investigation on hyperthermia by low-frequency ultrasonic].

Ultrasonic heating methods for hyperthermia have been developed because of several advantage i.e., its easiness in steering the applicator for the target, and its non-interference with other electronic equipment. Most of them make hot spots by focusing the ultrasonic beam, using acoustic lens or many transmitters. Therefore, these methods are based on analogous idea to the ray focusing, and higher frequency, i.e., from 500 kHz to 5 MHz, is used. However, there are some problems; hot spots are generated before the focus, and it is difficult to heat the region beyond gas and bones owing to the attenuation and scattering of the ultrasonic beam. Then, we propose a new method for heating the depths and local regions of the body. In this method, to heat the depths of the body low-frequency ultrasound is used since it has larger penetration depth and it is less scattered than higher-frequency ultrasound. To heat only tumours, hot spots are generated by synthesizing acoustic fields resulted from several incident waves. The heat generation and temperature distribution was analyzed using the models with properties similar to tissues for different values of parameters such as frequency, position and the number of sources. The results show that hot spots can be generated at the depths of the body. and that desirable temperature distribution can be obtained by selecting optimal parameters and cooling condition. To determine the temperature distribution more accurately it would be required to introduce the more complicated model of heat removal effect by blood flow and the experimental results. These problems are left for the future investigation.

Humans↗
PubMed1988

Multiple principal sigma factor homologs in eubacteria: identification of the "rpoD box".

Genes for the principal sigma factor (rpoD genes) of various eubacteria were identified with a synthetic oligonucleotide probe corresponding to a conserved sequence in rpoD gene products of Escherichia coli and Bacillus subtilis. Multiple rpoD homologs were found in the strains of Micrococcus, Pseudomonas, and Streptomyces, whereas single genes were detected in E. coli, B. subtilis, and Staphylococcus aureus. The four rpoD homologs of Streptomyces coelicolor A3(2) were cloned and sequenced. A homologous portion with 13 amino acids was found in the rpoD genes of S. coelicolor A3(2), E. coli, and B. subtilis and was named the "rpoD box."

Amino Acid Sequence↗
PubMed1988

[Effect of intra-thoracic administration of an immune modulator (OK-432) with anti-cancer drugs (ADR and MMC)].

Fourty-three patients with pleuritis carcinomatosa have been treated with an intra-thoracic administration in four distinct ways: Adriamycin alone, OK-432 alone, the combination of Adriamycin with OK-432, or the combination of Mitomycin C with OK-432. Judging from an evaluation of the subsequent chest X-rays, the prognosis of the cases which received the combination therapy of the two drugs was significantly better to that of the others. There were no significant differences between cases with primary lung cancer and those with other cancers. As for the side effects after the administration, there were no side effects, such as the trouble the renal function or liver function, other than fever and a decrease in the W.B.C.

Adjuvants, Immunologic↗
PubMed1988

Estimating ultrasonic parameters of biological tissue by adaptive filtering technique.

Diagnostic ultrasonic imaging is widely used as a non-invasive technique for examining the body. However, the resolution of images still does not meet the order of the wavelength, and only a part of the information on tissue characteristics contained in reflected signals is used. In this paper we propose a method for estimating two tissue parameters; i.e., the reflection coefficient and attenuation coefficient from the reflected ultrasound for the purpose of improving the resolution of ultrasonic images and obtaining information on tissue characterization. The reflection coefficient is estimated by a deconvolution technique using a Kalman filter, taking into account the distortion of the propagating pulse due to frequency-dependent attenuation. The attenuation is estimated by adaptive processing based upon the criterion function calculated using estimates of the reflection coefficient. Simulated signals are used to investigate the ability of this method. Additionally, experimental results for reflected signals from a human liver show that the method is applicable to clinical cases.

Filtration↗
PubMed1987

Estimation of tissue parameters derived from reflected ultrasound.

We propose a method of estimating two tissue parameters, that is, the reflection coefficient and attenuation coefficient from the reflected ultrasound for the purpose of improving the resolution of ultrasonic images and obtaining information on tissue characterization. The reflection coefficient is estimated by deconvolution technique using Kalman filter taking into account the distortion of the propagating pulse due to the frequency-dependent attenuation. The attenuation is estimated by adaptive processings based upon the criterion function calculated using estimates of the reflection coefficient. Simulated signals are used to investigate the ability of this method. Additionally, actual reflected signals from soft tissues are processed by the method. The results show that the method can be applied in clinical cases.

Animals↗
PubMed1987

[Severity of aortic stenosis assessed by Doppler techniques].

Continuous wave (CW) Doppler ultrasound has facilitated accurate estimates of pressure gradient (PG) across a stenotic valve. However, the severity of stenosis cannot be assessed using PG alone because it is dependent on actual flow across the valve. In this study, Doppler techniques were used to predict PG and aortic valve areas (AVA) in adults with aortic stenosis (AS). Fifty-four adult patients undergoing cardiac catheterization for suspected AS were prospectively evaluated. There were 28 men and 26 women, who ranged in age from 25 to 68 years with a mean of 56 years. These Doppler ultrasound studies were performed using a 2 MHz transducer and an Aloka SSD-730. With CW Doppler ultrasound, the highest velocities of the aortic jet were recorded from an apical approach. Left ventricular outflow flows were recorded about 1.0-1.5 cm below the aortic annulus using high PRF. Doppler waveforms were analyzed for the AT/ET (AT: acceleration time, ET: ejection time), and Doppler PG was calculated from the maximum velocity (V) of the aortic jet based on a modified Bernoulli equation (PG = 4V2), and aortic valve area was obtained using the continuity equation-(AVA = left ventricular outflow tract stroke volume divided by AS jet velocity integral). These data were compared with hemodynamic data obtained from cardiac catheterization. The following results were obtained: 1. In eight patients with substantial aortic regurgitation, whose maximum catheter PG were from 20 to 45 mmHg, the AT/ET was less than 0.30. The ratio of AT/ET correlated with the peak velocity of the aortic jet (r = 0.88) and the maximum PG (r = 0.87) obtained from cardiac catheterization. 2. In 46 patients with AS, the maximum PG by CW Doppler showed an excellent correlation with maximum catheterization PG (r = 0.97, SEE 6 mmHg), and the mean PG as calculated by the two techniques also disclosed a good correlation (r = 0.97, SEE 5.4 mmHg).(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1987

[Diagnosis of tricuspid stenosis by two-dimensional and pulsed Doppler echocardiography].

This study verified the usefulness of two-dimensional (2-D) and pulsed Doppler echocardiography (PDE) in the diagnosis of tricuspid stenosis (TS), and estimated the diastolic pressure gradient (PG) across the tricuspid valve (TV). Fifty-two patients with rheumatic mitral stenosis showing a decreased EF slope of the TV less than 40 mm/sec were studied. All patients underwent cardiac catheterization, and the mean diastolic pressure gradients (PG) across the TV were calculated with simultaneous recordings of right atrial and ventricular pressures. Based on surgical findings, all patients were categorized as the TS group consisting of 10 patients with TS (mean PG less than or equal to 5.0 mmHg; seven patients, greater than 5.0 mmHg; three patients), and the non-TS group consisting of 42 patients without TS. In three patients with PG exceeding 5 mmHg, the TV disclosed typical commissural fusions between the leaflets. 1. 2-D echocardiography The diagnosis of TS was made by recording diastolic doming and thickening of the TV in the parasternal long-axis and apical 4-chamber views. Among the 52 patients, 2-DE detected stenosis in all 10 patients with TS, for a sensitivity of 100%, while excluding TS in 40 of 42 patients without TS for a specificity of 95%. 2. Pulsed Doppler echocardiography The transtricuspid flow velocity in diastole was recorded from the apical window.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Diagnosis and treatment of metastatic bone tumor in the field of radiology].

From 1973 December to 1986 September, we have experienced 2,500 cases of radiation treatment, of which 237 cases have been with bone metastasis. X-ray CT was examined on the 19 cases to detect the bone metastasis. The detective rate was 89.5% with bone scintigram alone improved to 94.7% with both bone scintigram and X-ray CT. Serum Alkali phosphatase (Al-p) were measured after and before radiation treatment on 147 cases. Values of Al-p increased on 64.6% cases measured and when values of Al-p were decreased after radiation treatment, good treatment effects were showed. Electron microscope disclosed that Al-p has existed around cell membrane of metastatic tumor cell. We considered there is a correlation between increment of Al-p in blood and contents of Al-p in bone metastatic tissues. Judgement of effects of radiation treatments were scored by three grades of pain relieving on 217 cases. Effective rate showed 87.5%. Effective rate increased by using high dose rates irradiation with small fraction. Effective cases in relieving pain had longer survival than less ones. 26 cases which could not walk due to spinal cord paresis were treated by irradiation only or irradiation with decompression surgery. Walk recovery rate was 33% by radiation treatment only, on the other hand, by treatment with decompression surgery, it was 20%. Regarding as side effect, radiation myelopathy hardly occurred about 50 Gy (conventional irradiation method). We think if longer survival time is hoped, about 50 Gy is needed.

Alkaline Phosphatase↗
PubMed1987

[Diagnosis and treatment of bone metastasis].

Diagnosis and treatments of bone metastasis were reviewed with clinical experiments in National Medical center Hospital. As for diagnosis of bone metastasis, early detection of bone metastasis was significantly improved by using bone scintigrams recently progressed. But the results of reviews suggest the possible improvements in diagnosis of bone metastasis. X-CT (X-ray Computed Tomography) for diagnosis of bone metastasis is advantages in three dimensional delineation of the extend and spread of bone lesions in bone marrow over bone scintigram. MRI (magnetic resonance imaging) has clinically been developed since 1981, does not directly represent bone structures but soft tissues in bone marrow, giving useful information concerning changes and spread of metastatic bone tumor not only inside the bone but also around it. MRI is now in technical progress and expected some improvements, could be expected in early diagnosis of bone metastasis. Regarding as treatment, we have individually to choose from radiotherapy, hormonal therapy, chemotherapy, surgical therapy according to clinical circumstances and does themselves. Radiation treatment is widely approved not only much effective in relieving the pains from bone metastasis, but also it is considered at the first choice in treatment of the spinal cord paresis by vertebral metastasis, because of frequently bringing good therapeutic effects.

Bone Neoplasms↗
PubMed1986

[Doppler evaluation of porcine mitral valve dysfunction].

Seventy patients with bioprosthetic mitral valve were examined to study the applicability of the Doppler techniques including pulsed, continuous wave and color Doppler echocardiography in diagnosing and evaluating the severity of prosthetic valve dysfunction. The study population consisted of 70 patients who underwent mitral valve replacement (45 patients with Hancock valve, 13 with Angell-Shiley valve, 10 with Carpentier-Edwards valve). The dysfunctions were transvalvular regurgitation in 20 instances and paravalvular regurgitation in three, all of which were confirmed at surgery. A control group of 47 patients with the normally functioning porcine prosthetic mitral valve were also studied. Diastolic transmitral flow patterns were recorded from parasternal and apical approaches using color Doppler echocardiography, and the direction of the flow was definitely identified on the flow image. Transmitral flow signals spread from the mitral orifice to the mid-portion of the interventricular septum, and its direction was perpendicular toward the mitral ring in all cases. Flow velocity patterns in the left ventricle and atrium were recorded in the apical long-axis view of the left ventricle or apical four-chamber view using pulsed (high pulse repetition frequency) and continuous wave Doppler techniques. Two dynamic alterations in patients with the porcine mitral valve were evaluated from 1) the peak velocity and pressure half time (PHT) of transmitral flow in early diastole, and 2) the regurgitant jet in the left atrium indicating transvalvular or paravalvular regurgitation. The results were as follows: 1. Normally functioning porcine mitral valves were characterized by peak velocities (PV) less than or equal to 1.82 (mean +/- SD 1.44 +/- 0.27) m/sec and PHT less than or equal to 180 (mean +/- SD: 135 +/- 30) msec. In 23 patients with prosthetic valve dysfunction documented at surgery, peak velocity (mean +/- SD 2.23 +/- 0.19 m/sec) was significantly greater (p less than .001) than that of patients in the normally functioning prosthetic valves, and PHT ranged from 135 to 340 msec (mean +/- SD: 226 +/- 81 msec). 2. Among the 23 patients with porcine valve dysfunction, a harmonic striped pattern were recorded at the mitral valve levels in eight patients. All these patients had a musical murmur, and their peak velocity was more than 2.0 m/sec, but the PHT was less than 180 msec in seven patients. In these patients, valvular tears without calcification were confirmed at surgery.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗