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Biomedical subjects

O Iimura

Publications and source records attributed to O Iimura.

At least 217 records · Page 12Linked to original sources
PubMed1986

A case of lactate dehydrogenase (LDH)-IgG complex formation which causes low plasma LDH activity and an abnormal LDH isozyme pattern.

A case of an LDH-IgG complex formation which causes low plasma LDH activity and an abnormal LDH isozyme pattern was reported. A patient had pericarditis and myocardial hypertrophy of asymmetrical septal hypertrophy type. The same IgG was recognized in pericardial effusion. From a column chromatographic study, the molecular weight of LDH-IgG complex was estimated as being about 490,000. This complex was speculated as the IgG1-LDH2. The mechanism by which LDH-IgG is formed and the relationship between the complex itself and cardiac diseases remain unknown.

Aged↗
PubMed1986

The mechanism of the hypotensive effect of captopril (converting enzyme inhibitor) with special reference to the kallikrein-kinin and renin-angiotensin systems.

In order to clarify the mechanism of the hypotensive action of captopril, the acute and chronic effects of this drug on the kallikrein-kinin and renin-angiotensin systems were investigated respectively in 14 and 19 patients with hypertension. To determine the acute effect, a dose of 50 mg of captopril was administered once orally. For the chronic effect, 75-300 mg of the drug was administered daily for 14 days. In observations of the acute effect, blood pressure decreased significantly at 30 min. and maximally at 60-180 min. after administration with no change in heart rate. Significant increases in blood kinin levels and plasma renin activity (PRA), and a decrease in plasma angiotensin II levels were also observed. A marked augmentation was also found in urinary kinin excretion, but not in urinary kallikrein excretion. Moreover, the changes in blood pressure significantly correlated negatively with basal PRA, basal plasma angiotensin II and the changes in blood kinin levels, and positively with the changes in plasma angiotensin II. In our study of the chronic effect of captopril, similar changes in blood kinin levels, PRA, plasma angiotensin II levels, blood pressure and heart rate to the acute effect study were observed. Significant correlations of the changes in blood pressure were found negatively with basal PRA, basal plasma angiotensin II levels and the changes in blood kinin levels and positively with the changes in plasma angiotensin II levels. In addition, significant increases in urine volume and urinary sodium excretion occurred following administration of captopril for 14 days, and both increases negatively correlated with the changes in blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Localization of renal kallikrein-kinin system components in the kidney.

In a study using a stop-flow technique in dog kidney, the existence of kallikrein and kinin was recognized in distal tubules. The presence of kininase I was seen in both distal and proximal tubules, and also partly in the distal tubules. The presence of kininase II in the distal tubules was again confirmed by pretreatment with SQ14225. No evidence of kinin formation, however, was obtained in the proximal nephrons in stop-flow method. From these results, it was suggested that kininase I and II localized in proximal tubules may destroy the kinin filtered from glomeruli at the proximal level, while kallikrein and kininogen and also kininase I and II in the distal tubules may regulate the activity of the renal kallikrein-kinin system in the distal nephrons.

Animals↗
PubMed1986

[Qualitative determination of infarct segment by Fourier analysis using gated cardiac pool emission computed tomography].

As a new method for regional wall motion analysis, the tomographic functional images, including "coronal", "sagittal" and "four-chamber" sections, were produced by applying the fundamental Fourier analysis using gated cardiac pool emission computed tomography (POOL-SPECT). Segmental wall motion was qualitatively assessed from the functional images in 10 normal subjects and in 48 patients with myocardial infarction. The results were compared with those assessed by gated blood pool planar images (modified LAO 45), two-dimensional echocardiography (2DE) or contrast left ventriculography (LVG). The following results were obtained. 1. POOL-SPECT imaging could separate the ventricle in three dimensions from the neighboring cardiovascular system by avoiding the overlapping blood pool to make accurate recognition of regional wall motion. 2. The functional tomograms had greater clinical efficacy in the diagnosis of infarcted segments than did the conventional equilibrium method, with high sensitivity (93/99, 93.9%), specificity (128/141, 90.8%) and accuracy (221/240, 92.1%), especially in the apical and inferoposterior portions. 3. Tomographic functional imaging facilitated estimating segmental cardiac performance from spatial and temporal aspects. The amplitude image which expresses regional stroke volume was readily available to detect hypokinesis and akinesis. The phase image of the initial cardiac movement was very useful for diagnosing dyskinesis. 4. In comparing the qualitative analysis with 2DE or LVG, complete agreement was observed in 80% (128/160) and 85.1% (149/175) of segments, though POOL-SPECT imaging showed underestimations in 11% of the segments. In conclusion, POOL-SPECT can be performed repeatedly without potential risks and the tomographic functional images derived from application of Fourier analysis to POOL-SPECT images are very useful for qualitative and three-dimensional analysis of regional wall motion. Thus, this technique may be a promising procedure in clinical investigations, obviating the disadvantages of conventional methods.

Adult↗
PubMed1985

Plasma prolactin levels in patients with essential hypertension, malignant hypertension and secondary hypertension.

Plasma prolactin level and plasma renin activity were determined in normal subjects and patients with low and normal renin essential hypertension, renal hypertension, renovascular hypertension, primary aldosteronism, Cushing syndrome, pheochromocytoma and malignant hypertension. In both normal subjects and the normal renin essential hypertensives, plasma prolactin was significantly higher in females than in males. Plasma prolactin was also significantly higher in the normal renin essential hypertensives than in normal subjects of both sexes, while no significant difference was found between the low renin group and normal subjects of either sex. A significantly positive correlation was observed between plasma renin activity and the plasma prolactin level in male essential hypertensives, but not in females. Although no significant difference in plasma prolactin level could be detected between patients with secondary hypertension and normal subjects, this level was significantly higher in malignant hypertensives than in normotensives. From these results, it was shown that significant differences of plasma prolactin levels exist between normal renin essential hypertensives, and low renin essential hypertensives or normal subjects, and that these differences may partly depend on renin status which might be related to the central dopaminergic activity. In malignant hypertensives, the high level of plasma prolactin may be caused by diminished renal function, but the suppression of central dopaminergic activity cannot be excluded in the mechanism of plasma prolactin increment.

Adolescent↗
PubMed1985

The effect of blood volume changes accompanying isotonic circumstances on plasma antidiuretic hormone levels in normal subjects.

Changes in plasma ADH levels were investigated in human male subjects whose blood volume was altered under isotonic circumstances. Blood volume was reduced by ambulation and increased by isotonic saline infusion in an overnight dehydrated state, and determinations were made on plasma ADH levels, plasma osmolality and hematocrit values. Plasma ADH levels were clearly affected by the small changes in blood volume, and significantly negative correlation was found between plasma ADH levels and the percent changes in blood volume under isotonic circumstances. From these findings, it was concluded that ADH release in human subjects is also controlled by the changes of the blood volume factor in addition to osmotic stimuli.

Adolescent↗
PubMed1985

Urinary excretions of kininase I and kininase II activities in essential hypertension. A sensitive and simple method for its kinin-destroying capacity.

To further clarify the role of the renal kallikrein-kinin system in essential hypertension, a sensitive and simple method for the determination of both human urinary kininase I and kininase II was established, and the system components were determined in patients. In the measurement of kininase activity, desalted urine samples were incubated with synthetic bradykinin, and the reaction was terminated with kininase inhibitors, ethylene diamine tetraacetic acid and phenanthroline. Thus, kininase activity was determined as the kinin-destroying capacity. Moreover, the specific inhibitor for kininase II, SQ14225, was applied for the separation of kininase I and kininase II activities. Daily urinary excretions of total kininase and kininase I activities were significantly higher in essential hypertensive patients than those in normotensive subjects, whereas no difference was observed in kininase II activity. As reported previously, daily excretions of urinary kallikrein and kinin simultaneously determined in these patients were significantly lower than excretions in normotensive subjects. From these results, it was suggested that not only decreased renal kallikrein, but also increased kininase activity, may play an important role in the suppression of the renal kallikrein-kinin system through the reduction of active kinin level in essential hypertension.

Adolescent↗
PubMed1985

Studies on experimental coronary insufficiency. Effect of L-carnitine on myocardial ischemia produced by sympathetic-nerve stimulation with high plasma fatty acids.

Our previous studies revealed that sympathetic-nerve stimulation (SNSt) plays an important role in the precipitation and the augmentation of myocardial ischemia in dogs with coronary constriction. To clarify the underlying mechanism of the detrimental effect of free fatty acids (FFA) at a high plasma concentration and the beneficial effect of L-carnitine on myocardial ischemia, ischemic changes following SNSt were compared among three groups of dogs with mild or moderate coronary constriction: a saline control group, an intralipid [(IL) 0.1 ml/kg per min + heparin 5 mg/kg] group, and an IL + L-carnitine (200 mg/kg) group. High plasma concentration of FFA aggravated the ischemic changes induced by SNSt in dogs with coronary constriction, in which no signs of increase in myocardial oxygen consumption were seen. L-Carnitine clearly alleviated the mechanical dysfunction, acceleration of anaerobic metabolism, depletion of myocardial contents of high-energy phosphates, myocardial accumulation of lactate, and ECG ischemic changes that were augmented by high plasma FFA in the coronary-constricted dogs with SNSt. From these findings, it was suggested that an increased plasma FFA might aggravate myocardial ischemia, at least, produced by SNSt in dogs with mild or moderate coronary constriction and that L-carnitine might improve the ischemia augmented by FFA, presumably by reducing myocardial accumulation of FFA intermediates.

Animals↗
PubMed1984

A very sensitive direct radioimmunoassay system for plasma angiotensin II and its clinical application in various hypertensive diseases.

A very sensitive and simplified direct radioimmunoassay system for plasma angiotensin II was developed using the antiserum against synthetic angiotensin II (final dilution = 1: 1,500,000) in combination with 125I-labeled angiotensin II (specific activity = 1,600 microCi/micrograms). In this assay system, it was possible to carry out a direct assay using 100 microliter of plasma without any extraction procedure. This conclusion was supported by 100% recovery, parallelism of plasma samples against the standard curve, and no difference in hormone levels, there was also a high positive correlation between the plasma angiotensin II levels measured by this direct assay and the dowex column extraction method. The sensitivity of this assay system was 0.1 pg/tube, which is the highest sensitivity in studies reported to date. The cross-reactivities of angiotensin III and I against this antiserum were 100% and less than 0.1%, respectively, suggesting that the antiserum was very specific for the C-terminal of angiotensin II. Plasma angiotensin II levels in normal subjects after overnight fasting ranged from 3.0 to 21.3 pg/ml (12.0 +/- 2.1 pg/ml, mean +/- SE). By comparison, plasma angiotensin II levels of patients with essential hypertension were similar to those in the normal renin group, lower than those in low renin group and higher than those in high renin group. In patients with secondary hypertension, levels were lower in those with primary aldosteronism and higher in those with renovascular hypertension when compared to normal subjects.

Angiotensin II↗
PubMed1984

Plasma noradrenaline concentration and pressor response to infused noradrenaline in patients with borderline hypertension, and mild or moderate essential hypertension.

In order to evaluate the significance of sympathetic nerve activity in the pathophysiology and pathogenesis of borderline hypertension or mild or moderate essential hypertension, plasma noradrenaline concentration (PNA) at supine rest and pressor response to infused noradrenaline (NA-R) were evaluated in these in-patients. A significantly positive correlation (r = 0.395, p less than 0.001) between PNA and age was found in normotensive subjects (NT), but not in essential hypertensives (EHT). In the young (below 40 years of age) group, the mean value of PNA in EHT was significantly higher (p less than 0.05) than that in NT. However no significant difference in PNA between NT and EHT was observed in the middle-age (40-59 years) and old-age (above 60 years) groups. PNA was highest in borderline hypertensives (BHT), second highest in EHT with WHO stage I (WHO-I), third in EHT with WHO stage II (WHO-II), and lowest in NT. Among these age-matched four groups, significant differences in the mean value of PNA were found between NT and BHT (p less than 0.001) or WHO-I (p less than 0.05), and between BHT and WHO-II (p less than 0.05). In a comparison of the age-matched NT, normal renin EHT (NRH) and low renin EHT (LRH), the mean value of PNA in NRH was significantly higher than that in NT (p less than 0.001) and LRH (p less than 0.001). Similar differences were observed in the peak value of PNA during 20 minutes when the head was tilted up. A close positive correlation between PNA and simultaneously measured mean arterial pressure (MAP) in the young EHT (r = 0.698, p less than 0.001) and WHO-I (r = 0.631, p less than 0.001), and a weak correlation in the middle-age EHT (r = 0.435, p less than 0.05) and NRH (r = 0.311, p less than 0.05) were demonstrated immediately after hospital admission. In the old-age EHT, WHO-II and LRH, however, no significant correlation was found between PNA and MAP. The mean value of NA-R in young (p less than 0.005) and middle-aged EHT (p less than 0.001) was significantly greater than that in respectively age-matched NT.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗