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Biomedical subjects

T Tsubokura

Publications and source records attributed to T Tsubokura.

At least 19 recordsLinked to original sources
PubMed1992

Lack of effect of parathyroid hormone on calcium homeostasis in rat platelets.

The in vitro effects of parathyroid hormone on Ca2+ handling by fura-2 loaded rat platelets were studied. The incubation of these platelets with rat parathyroid hormone (1-34) for 10 min had no effect on intracellular fura-2 metabolism or [Ca2+]i in the resting state. The [Ca2+]i response to 0.1 U/mL thrombin was unaffected by preincubation with parathyroid hormone in the presence or absence of extracellular Ca2+. Furthermore, the recovery rate of [Ca2+]i after the thrombin-induced peak in Ca(2+)-depleted media was not altered with parathyroid hormone. These data indicate that parathyroid hormone may not have a significant effect on Ca2+ homeostasis in rat platelets in unstimulated and stimulated conditions.

Animals↗
PubMed1991

[A case of undiagnosed pheochromocytoma caused by negative metoclopramide test].

Metoclopramide (MCP), a dopamine antagonist, was recently used as the pharmacological test for the diagnosis of pheochromocytoma. There have been no reports involving false negative cases in the MCP test. We experienced a rare case of pheochromocytoma which showed a negative MCP test, and it caused a failure of the diagnosis. A 51-year-old man visited our hospital with a sudden onset of headache and palpitation. Blood pressure was 218/98 mmHg at another hospital. When he came to our hospital, blood pressure returned to normal (120/80 mmHg), and both serum adrenaline (E) and noradrenaline (NE) were within normal limits. A computed tomography, magnetic resonance imaging, and angiography demonstrated a 1.8 x 1.8 cm right adrenal mass. No changes in blood pressure and plasma catecholamine were observed following the injection of 10 mg of MCP. The pathologically resected right adrenal gland contained a typical pheochromocytoma which was 1.0 x 1.0 cm in size and weighed 8 g. The detailed mechanism of the negative MCP test in this case was not known but might be related to the small size of the tumor.

Adrenal Gland Neoplasms↗
PubMed1991

Effects of volume loading on left atrial systolic time intervals.

The effects of volume loading on the left atrial preejection period (LAPEP) and left atrial ejection time (LAET) were examined in 24 patients with various heart diseases using pulsed Doppler echocardiography. In response to volume loading, the left atrial dimension before atrial contraction significantly increased from 30.6 mm +/- 5.8 mm to 32.4 mm +/- 5.4 mm and the change in the left atrial dimension during atrial contraction tended to increase. The peak velocity in the atrial contraction phase significantly increased from 58 cm/s +/- 14 cm/s to 63 cm/s +/- 13 cm/s, and the integral of the atrial contraction phase tended to increase. LAPEP significantly decreased from 114 ms +/- 16 ms to 104 ms +/- 14 ms and LAET significantly decreased from 128 ms +/- 15 ms to 124 +/- 12 ms. The relation between LAET and left ventricular end-diastolic pressure, and that between LAPEP and mean pulmonary capillary wedge pressure, shifted downward to the right after volume loading. Thus, left atrial ejection is augmented by volume loading according to the Frank-Starling mechanism, while LAPEP decreases due to an increase in preload and LAET decreases due to an increase in afterload.

Atrial Function, Left↗
PubMed1991

Fuzzy realization in clinical test database system.

To be able to obtain useful information from medical data easily and quickly in daily use for the hospital staff, it is necessary to construct a proper database system using methodologies suitable for the nature of medical data. From this viewpoint we have developed the clinical test relational database system at Hiroshima University Hospital, which provides the functions of easy on-line retrieval and statistical analysis. Fuzzy query processing based on the fuzzy set theory is adopted in the system. This enables us to use natural linguistic representation and makes it easy to introduce medical knowledge representation. Fuzzy set approaches turn out to be superior in clinical evaluation of laboratory data to the ordinary clear-cut definition of normalcy.

Artificial Intelligence↗
PubMed1991

Determinants of left atrial systolic time intervals--assessment by pulsed Doppler echocardiography.

To evaluate the responsible factors for left atrial ejection, the left atrial preejection period (LAPEP), i.e., the time interval between atrial pacing pulse and onset of atrial ejection, and left atrial ejection time (LAET), i.e., the duration of atrial ejection, were determined from mitral inflow velocity patterns in 35 patients with various heart diseases using pulsed Doppler echocardiography. LAPEP ranged from 75 to 157 (mean 110 +/- 18) msec and LAET from 80 to 169 (mean 124 +/- 19) msec. The left atrial dimension before atrial contraction showed no significant correlation with LAPEP or LAET. Peak velocity during atrial contraction was negatively correlated with LAPEP (r = -0.42, p less than 0.05) and positively with LAET (r = 0.56, p less than 0.01). Left ventricular end-diastolic pressure (LVEDP) indicated a significant negative linear correlation with LAET (r = -0.44, p less than 0.05). LAPEP showed no significant linear correlation with LVEDP, but a significant curvilinear relationship was observed between them (LAPEP = 169 - 9.LVEDP + 0.28.LVEDP2, r = 0.63, p less than 0.001). Mean pulmonary capillary wedge pressure (mPCWP) was curvilinearly related to LAPEP (LAPEP = 168 - 11.mPCWP + 0.42.mPCWP2, r = 0.72, p less than 0.001) and LAET (111 + 4.1.mPCWP - 0.22.mPCWP2, r = 0.63, p less than 0.001). Although LAPEP decreased and LAET increased with increase in mPCWP up to about 15 mmHg, the reverse situation was noted for greater mPCWP. Thus, the major determinants of left atrial systolic time intervals are left atrial and ventricular pressures, and peak velocity during atrial contraction.

Adult↗
PubMed1991

Hemodynamic response to dietary sodium loading in essential hypertension studied with Doppler echocardiography.

The cardiac response to dietary salt loading was assessed by Doppler echocardiography during various sodium intakes (52-345 mEg per day) in 30 patients with essential hypertension. The Mitral flow velocity integral in the rapid filling phase (IntR) and the atrial contraction phase (IntA) was measured from the transmitral flow pattern, and the sum of IntR and IntA (IntR + IntA), the ratio of IntA to IntR (IntA/IntR), cardiac output (CO) and total peripheral resistance (TPR) were calculated. With salt loading, the mitral flow pattern remained almost unchanged in the nonsalt-sensitive (NSS) patients. Fourteen of the 19 salt-sensitive (SS) patients showed significant increases in IntR + IntA and CO with salt loading (IntR + IntA, from 13.9 +/- 2.8 to 17.9 +/- 3.6 cm, p less than 0.01; CO, from 6021 +/- 2130 to 8305 +/- 1699 ml/min, p less than 0.01), and were termed "salt-sensitive CO-dependent" (SS [COdep]), suggesting that the apparent pressor response to sodium loading was mediated by an increased CO. In the remaining five SS patients termed "salt-sensitive CO-independent" (SS [COindep]), IntA/IntR increased significantly with sodium repletion (from 0.66 +/- 0.23 to 0.90 +/- 0.31, p less than 0.01), without a significant change in IntR + IntA. Increments in IntA/IntR observed in the SS [COindep] patients were considered to be due to an elevation of total peripheral resistance (TPR), since changes in IntA/IntR were significantly correlated with those in TPR in all subjects (r = 0.617, p less than 0.01).

Adult↗
PubMed1991

[Clinical study on soluble interleukin-2 receptor in patients with sarcoidosis].

Levels of soluble IL-2 receptor in sera of 18 patients with sarcoidosis were measured by a sandwich ELISA method established by the authors and were found to be significantly higher than those in sera of normal subjects. Levels of soluble IL-2 receptor in sera of sarcoidosis cases of bilateral hilar lymphadenopathy (BHL) were significantly higher than those in sera of sarcoidosis cases without BHL. In patients with sarcoidosis, levels of soluble IL-2 receptor did not differ in relation to the presence or absence of ocular lesions, or in relation to positive or negative response to protein purified derivative of tuberculosis (PPD).

Adult↗
PubMed1991

[The development and the applications of clinical laboratory system by using of fuzzy set theory].

For clinical laboratory data to be used effectively in wide areas of clinical medicine, it must be stored in proper database systems. Moreover, the system must be installed in the hospital information system for easy access by the hospital staff in their routine activities. From this standpoint we have developed a clinical test relational database system at Hiroshima University Hospital, which provides the functions of easy on-line retrieval and statistical analysis. We have also improved the functions to incorporate fuzzy query processing based on the theory of fuzzy sets. This system enables us to use natural linguistic representation and leads to a medical knowledge-base.

Clinical Laboratory Information Systems↗
PubMed1990

Assessment of supra-valvular abnormal signal with color Doppler flow mapping in patients with aortic regurgitation.

A supra-aortic abnormal flow signal (proximal acceleration) was studied in 62 patients with aortic regurgitation with the use of color Doppler flow mapping. The proximal acceleration signal was detected in 28 of the 62 patients and was shaped like a V or a teardrop. In the 29 patients who underwent aortography, a proximal acceleration signal was observed in all 18 patients with severe and moderate regurgitation and in only one of the 11 patients with mild regurgitation. The sensitivity for the diagnosis of severe regurgitation from the existence of a proximal acceleration signal was 100%, specificity 50%, and predictive accuracy 47%. A close correlation between the area of the proximal acceleration signal and the width of the aortic regurgitant jet signal was observed (r = 0.81). An acceleration area of 45 mm2 or more was observed in eight of the nine patients with severe regurgitation, in four of the nine patients with moderate regurgitation, and in none of the patients with mild regurgitation. Sensitivity for the diagnosis of severe regurgitation from an area of proximal acceleration of more than 45 mm2 was 89%, specificity 80%, and accuracy 67%. These results suggest that evaluation of the area of the supra-aortic abnormal signal may be a useful auxiliary aid in estimating the severity of aortic regurgitation.

Adolescent↗
PubMed1990

Assay for the soluble interleukin-2 receptor by sandwich enzyme linked immunosorbent assay.

A system for the detection of soluble IL-2R by sandwich enzyme linked immunosorbent assay (ELISA) was established. This assay system has good reproducibility, and was found to be specific for soluble IL-2R by examination of the binding of anti-IgM antibody or anti-IL-2R monoclonal antibody (mAb) with IgM or soluble IL-2R and inhibition by IL-2 of the binding of anti-IL-2R mAb to soluble IL-2R. The IL-2R molecules in supernatant of phytohemagglutinin-stimulated peripheral blood mononuclear cells were of 44,000-61,000 molecular weight as estimated by size of exclusion high performance liquid chromatography. The results of determinations for soluble IL-2R with a Eurogenetics kit (sandwich enzyme linked immunosorbent assay) were significantly correlated with those by the our method.

Enzyme-Linked Immunosorbent Assay↗
PubMed1990

[Left atrial systolic time intervals: their relations to left atrial preload, afterload and acute left ventricular pressure loading].

Using pulsed Doppler echocardiography, the left atrial pre-ejection period (LAPEP) and left atrial ejection time (LAET) were studied in relation to left atrial loading and acute left ventricular pressure loading conditions in 17 patients with various heart diseases. LAPEP was defined as the time interval from the onset of a right atrial pacing pulse to the upstroke in the atrial contraction phase on the mitral flow velocity pattern; LAET was defined as the duration of left ventricular filling due to atrial contraction. 1. LAPEP did not correlate significantly with mean pulmonary capillary wedge pressure (mPCWP) indicating preload for the left atrium, nor with left ventricular end-diastolic pressure (LVEDP) indicating afterload for the left atrium. There were significant inverse correlations of LAET with mPCWP (r = -0.72) and with LVEDP (r = -0.75). 2. LAPEP, LAET and LAPEP/LAET correlated significantly with the ratio of the peak velocity in the atrial contraction phase and to that in the rapid filling phase (r = -0.62, -0.50 and -0.59, respectively). There was a significant inverse correlation of LAPEP/LAET with the left ventricular ejection fraction (r = -0.62). 3. When left ventricular systolic pressure became elevated by 25% of its basal value at a constant right atrial pacing rate, LAPEP decreased from 110 +/- 21 msec to 103 +/- 22 msec (p less than 0.05), LAET increased from 123 +/- 33 msec to 129 +/- 24 msec and LAPEP/LAET decreased from 0.95 +/- 0.37 to 0.84 +/- 0.32 (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[A case of cardiac tamponade showing respiratory variation in inflow and outflow velocities in both ventricles and venous return].

A case of a 62-year-old man with a large pericardial effusion is presented. He developed clinical signs of cardiac tamponade. Two-dimensional echocardiography revealed collapse of the right ventricle in early diastole and inversion of the free wall of both atria in systole. Pulsed Doppler echocardiography demonstrated an abnormally increased respiratory variation in transvalvular blood flow velocities. Expiration caused an increase in the flow velocities across the mitral and aortic valves, and a decrease in the flow velocity across the tricuspid valve. The exaggerated respiratory variations in transvalvular flow velocities suggest that Doppler evaluation may be a valuable adjunct in the diagnosis of cardiac tamponade.

Blood Flow Velocity↗
PubMed1989

Diastolic atrioventricular valve closure and regurgitation following atrial contraction: their relation to timing of atrial contraction.

Some authors have proposed that atrial contraction per se is able to close the atrioventricular (AV) valves. To determine whether tight closure of the AV valves can be accomplished solely by atrial contraction, the existence of diastolic regurgitation following atrial contraction and its relation to the PQ interval were examined in 13 patients with AV block (2 of the first degree, 4 of the second degree, and 7 of the third degree), using pulsed Doppler echocardiography, which allowed noninvasive estimation of valvular regurgitation in the physiological state. Diastolic mitral and tricuspid regurgitations were detected in the left and right atria near the respective AV valves in all 13 patients despite different degrees of AV block, while these valves were observed to be in apparently closed position during regurgitation on the two-dimensional and M-mode echocardiograms. The duration of regurgitant signals was prolonged with an increase in the PQ interval in the electrocardiogram, but it became short again as the P wave approached the preceding rapid filling wave. These results suggest that atrial contraction may initiate the closure of the AV valves but is not capable of closing the valves tightly, and atrial contraction with long PQ interval may contribute little to augmentation of cardiac output in patients with AV block.

Echocardiography, Doppler↗
PubMed1989

A monoclonal anti-platelet antibody which recognizes p55 antigen.

A monoclonal antibody (MoAb) H229(IgGl) was obtained by fusion between SP2/0, mouse myeloma cell line and spleen cells from BC3Fl mice immunized with HEL, a erythroleukemia cell line. MoAb H229 precipitated a 55 kilodalton(KD) molecule in reduced condition. It reacted with platelets and megakaryocytes, but not with monocytes, granulocytes, lymphocytes, thymocytes, red blood cells (RBC), colony-forming units-granulocyte/monocyte (CFU-GM), and burst forming units- erythroid (BFU-E). These findings suggest that MoAb H229 reacts with platelets specifically. However, MoAb H229 did not inhibit platelet aggregation induced by ristocetin, ADP, epinephrine and collagen.

Animals↗
PubMed1988

Intralymphocytic sodium and free calcium and plasma renin in essential hypertension.

Intracellular sodium, potassium, and free calcium concentrations were investigated in lymphocytes of 30 patients with essential hypertension and 30 normotensive controls. All subjects were placed on a diet containing 8 to 10 g of sodium chloride per day. Lymphocyte sodium concentration was higher in hypertensive patients than in normotensive controls (19.8 +/- 1.8 vs 18.4 +/- 1.8 mmol/kg wet weight; p less than 0.01), whereas lymphocyte potassium concentration was similar in both groups. Lymphocyte free calcium concentration was also higher in hypertensive patients than in normotensive controls (134.6 +/- 13.2 vs 120.2 +/- 16.4 nmol/L; p less than 0.01). There was a positive correlation between lymphocyte sodium and free calcium concentrations in normotensive controls, in hypertensive patients, and in the subjects combined (r = 0.59, p less than 0.01; r = 0.71, p less than 0.001; and r = 0.70, p less than 0.001, respectively). Lymphocyte potassium concentration was not related to lymphocyte sodium or free calcium concentration in each group. In patients with essential hypertension, intracellular sodium and free calcium concentrations were negatively correlated with plasma renin activity (r = -0.66, p less than 0.001; r = -0.60, p less than 0.001, plasma norepinephrine concentration. These results suggest that a considerable relationship exists between intracellular sodium and free calcium in lymphocytes and that, in essential hypertension, the alteration in cellular metabolism of sodium and calcium may be linked to the renin system but not to blood pressure, age, or adrenergic activity.

Adult↗