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Biomedical subjects

H Ijichi

Publications and source records attributed to H Ijichi.

At least 145 records · Page 8Linked to original sources
PubMed1982

Effect of sodium loading and depletion on cyclic nucleotides in plasma and aorta. Interaction between prostacyclin and cyclic nucleotides.

The present study evaluated the effect of sodium loading and sodium depletion on cAMP and cGMP content of rat aorta. Enhanced generation of prostacyclin (PGI2) in aorta was noticed in sodium loading and sodium-depletion. As PGI2 is potent vasoactive agent, the interaction between PGI2 generation in the aorta and cyclic nucleotide accumulation in the aorta was investigated. Sodium depletion of rats induced the elevation of both cAMP and cGMP in the aorta and of cAMP in plasma. No change in cyclic nucleotides was noticed following sodium loading. These changes in cyclic nucleotides were felt to reflect the fluctuation of vasoactive agents under various sodium metabolism conditions. These observations may indicate that PGI2 is not a major factor in the regulation of cyclic nucleotide metabolism under sodium loading and sodium depletion. The increased accumulation of cAMP and cGMP in rat aorta in sodium depletion may be due to the cumulative effects of PGI2, catecholamine and probably angiotension II which are induced by sodium depletion.

Aldosterone↗
PubMed1982

Measurement of serum thyroxine binding prealbumin in various thyroidal states by radioimmunoassay.

Serum thyroxine binding prealbumin (TBPA) levels in various thyroidal states were examined by radioimmunoassay (RIA). This technique is highly sensitive, accurate and reproducible. The normal mean (+/- 2SD) level of serum TBPA is 26.9 +/- 8.0 mg/dl (29.4 +/- 5.2 in men and 24.9 +/- 7.6 mg/dl in women). Serum TBPA levels in pregnant women were significantly lower than in normal females (P less than 0.05). Serum TBPA levels in patients with untreated hyperthyroidism were 12.9 +/- 4.0 mg/dl (mean +/- SD) and in patients with untreated hypothyroidism were 25.2 +/- 4.7 mg/dl (mean +/- SD). The mean TBPA concentrations in untreated hyperthyroidism were significantly lower than that for normal population (P less than 0.01), but untreated hypothyroidism was almost within normal range. The changes in TBPA levels in hyperthyroidism and hypothyroidism were similar to those in TBG levels. In untreated hyper- and hypothyroidism, restoration to euthyroidism by treatment was uniformly accompanied by a normalization of serum TBPA and TBG levels. A negative correlation between serum thyroid hormone binding protein (TBG and TBPA) and free thyroxine was observed in patients with hyperthyroidism. The coefficient of correlation between TBPA and free thyroxine was -0.80 (P less than 0.01) and between TBG and free thyroxine -0.58 (P less than 0.01). From these experiments it appears that not only TBG but also TBPA may play an important role in the regulation of the free thyroxine concentration in response to various thyroidal states.

Female↗
PubMed1982

Comparative study of two methods of estimating sinoatrial conduction time in patients with abnormal sinus node function.

This study compared a new method to estimate sinoatrial conduction time (SACT) using continuous atrial pacing proposed by Narula et al with the widely used method using premature atrial stimulation originally proposed by Strauss et al. The estimated SACTs by the two methods were obtained in 19 patients with normal sinus node (SN) function (Group A) and 8 patients with abnormal SN function (Group B). Estimate of the SACT by the Narula method was taken as the difference between the first atrial return cycle after pacing and the basic sinus cycle length (BSCL). The Narula method was performed for a train of 8 consecutive beats at three different pacing cycle length (PCL); PCL (1) greater than or equal to BSCL--50, PCL (2) greater than or equal to BSCL--100 and PCL (3) greater than or equal to BSCL--150 msec. In group A, the estimated SACTs by the Strauss method was 185 +/- 49.3 msec, meanwhile the SACTs by the Narula method were 148 +/- 80.7 at PCL (1), 181 +/- 58.7 at PCL (2) and 212 +/- 84.5 msec at PCL (3) (mean +/- SD); the coefficient of correlation between the Strauss method and the Narula method were 0.58, 0.84, and 0.67, respectively. On the other hand, in group B, atrial return cycles by the Narula method were abnormally prolonged (over 215 msec) in 5 of 8 cases (63%) even at PCL (2) and in all of the cases (100%) at PCL (3). By the Strauss method, SACTs in 6 of 8 cases could not be defined; however it was possible to assess the type of SN dysfunction by the pattern of the atrial return cycles. In conclusion, the estimated SACT by the Narula method at PCL (2) corresponded well with the SACT by the Strauss method in patients with normal SN function. However, it was difficult to determine SACT in patients with Sick Sinus Syndrome by both methods.

Adult↗
PubMed1982

Enhanced vascular reactivity to norepinephrine in salt-sensitive patients with hypertension.

Twenty patients with hypertension were studied under diets containing low and high salt to identify factors which might be involved in elevating blood pressure under sodium-loading. They were classified as "salt-sensitive" (SS) and "nonsalt-sensitive" (NSS) according to the presence or absence of greater than 10% increases in mean blood pressure when a low salt diet was replaced by a high salt diet. During high-sodium intake, the SS patients showed reduced urinary excretion of sodium and elevated plasma levels of aldosterone as compared with plasma renin activity. The SS patients also showed an enhanced pressor response to norepinephrine under both low-sodium and high-sodium diets. From these results, it is suggested that the sodium retention, which is probably related to nonsuppressed levels of PAC under sodium-loading, is one of the factors in elevating blood pressure in the SS patients. Moreover, the enhanced pressor response to norepinephrine seems to contribute, in part, to elevation of blood pressure in the SS patients under salt-loading.

Aged↗
PubMed1982

Central vasopressor responses to conjugated estrogens in rats may be mediated via a renin-angiotensin system in the brain.

Central effects of sex steroids on cardiovascular regulation and on behavior were investigated by injecting conjugated estrogens i.c.v. in conscious or anesthetized rats. Conjugated estrogens (0.1-10 micrograms) produced dose-related increases in pressure and behavioral excitation in all rats and drinking in some rats. Marked increases ii pressure and excitation with tonic convulsions resulting in death were produced by similar injections of conjugated estrogens (100 micrograms). Pretreatment with angiotensin I converting enzyme inhibitor or angiotensin II analog abolished both vasopressor responses and behavioral excitation in conscious rats. When rats were later anesthetized with urethane to allow recording of sympathetic nerve activity, 10 and 100 micrograms of conjugated estrogens produced dose-related vasopressor responses accompanied by corresponding increases in peripheral sympathetic nerve activity. Again, converting enzyme inhibitor or angiotensin II analog abolished the increases in both blood pressure and sympathetic nerve activity. By contrast, when conjugated estrogens were injected i.v. up to 2 mg/kg, neither blood pressure nor sympathetic outflow was affected. Collectively, our results suggest that conjugated estrogens infused centrally activate a renin-angiotensin system in the brain, which results in sympathetic hyperactivity leading to blood pressure elevation.

Animals↗
PubMed1982

[Two-dimensional echocardiographic evaluation of the right ventricular wall in hypertension and hypertrophic cardiomyopathy].

The thickness and motion of the right ventricular wall (RVW) were studied with two-dimensional echocardiography from a subxiphoid approach in 20 normal subjects (N Group), 86 patients with hypertension (HT Group) and 20 patients with hypertrophic cardiomyopathy (HCM Group). Comparison was made between the patients with and without echocardiographic RVW hypertrophy in each patient group in regard to the thickness of the interventricular septum (IVS) and the left ventricular posterior wall (LVPW) as well as the motion of the RVW and cardiac catheterization data. 1. RVW hypertrophy was visualized in 39.5% of the HT Group and in 40% of the HCM Group. There was no difference in the thickness of RVW between the two groups. 2. A localized hypertrophy and an abnormal motion of RVW were obtained in the HCM Group, but not in the HT Group. 3. RVW hypertrophy in the HT Group was seen in patients with marked IVS hypertrophy, while that in the HCM Group was not related to IVS hypertrophy. 4. Pulmonary arterial pressure remained normal in each group. Therefore, RVW hypertrophy did not appear to be the result of pressure overload. 5. Right atrial mean pressure and right ventricular end-diastolic pressure were elevated only in HCM patients with RVW hypertrophy. We conclude that there is a different mechanism in the mode of production of RVW hypertrophy between patients with hypertension and those with hypertrophic cardiomyopathy.

Cardiac Volume↗
PubMed1982

[A case of malignant melanoma responded to chemotherapy including DTIC and local injection of OK-432].

A 33-year-old woman with malignant melanoma well responded to a chemotherapy including DTIC, ACNU, and VCR, and intralegional injection of OK-432. Four years prior to admission, a lentigo of 5 mm diameter at her left frontal chest was found, but, histological examination resulted in no distinctly malignant findings. In November 1979, multiple subcutaneous tumors appeared over posterior surface of the chest and left axillar region, which were gradually increasing in number and size, then she was admitted to our hospital in June, 1980. Biopsy of subcutaneous tumors revealed a malignant melanoma and its metastasis to skin. Immunochemotherapy was started immediately based upon this diagnoses. The patient received 100mg DTIC i.v. for 4 days, 100mg ACNU i.v. for one day and 1 mg VCR i.v. for one day. OK-432 was locally injected into some tumors as an immunotherapy. On completion of the third course of chemotherapy, all subcutaneous tumors were decreased in size, especially the tumors injected with OK-432. However, patient didn't respond to a repeated chemotherapy, thereafter malignant melanoma was metasized to uterus and peritoneum in May, 1981, and she died in September, 1981. Major side effects of this chemotherapy were nausea and mild transient leukocytopenia. The combination of chemotherapy including DTIC and local injection of OK-432 appeared to be effective for malignant melanoma.

Adult↗
PubMed1982

[Cardiotoxicity of daunorubicin and aclacinomycin A in patients with acute leukemia].

Anthracycline antibiotics are principal agents in the treatment of acute non-lymphocytic leukemia, although the usefulness are limited by their adverse side effects, especially by the cardiotoxicity. Aclacinomycin A (ACM) is known to be a new anthracycline antibiotic which has been isolated from Streptomyces galilaeus, and its cardiotoxicity on the experimental animal systems was reported to be more than 10 times lower than that of adriamycin. We investigated the cardiotoxicity of ACM on 29 patients with acute leukemia and compared it with daunorubicin (DNR). The measurement of STI (PEP:LVET) has been recommended to be convenient method of assessing the anthracycline cardiotoxicity, but through out analytical study, QTC measurement was proved to be more valuable for the simple and rapid detection of the cardiotoxicity induced by the agents. In comparison with the QTCs in DNR and ACM, the cardiotoxicity of ACM was much lower than that of DNR, and the reversibility of ACM induced cardiotoxicity was much more rapid. Moreover, these effects were observed even in the patients treated with the maximum dose of DNR. Therefore, ACM was expected to be one of the agents of the first choice for the relapsed cases of acute leukemia, especially APL.

Aclarubicin↗
PubMed1982

[Analysis of end-systolic pressure-volume relation by gated radionuclide angiocardiography].

Left ventricular end-systolic pressure-volume relation has been proved experimentally to be an useful index of left ventricular contractility relatively independent of preload or afterload. But less clinical application has been reported because of its invasive nature, and we evaluated this relationship non-invasively using gated radionuclide angiocardiography as volume determination and cuff sphyngomanometer in the arm as pressure measurement. Gated equilibrium blood pool scintigrams were obtained at rest and during intravenous infusion of angiotensin or nitrate. Ventricular volumes were derived from ventricular activity and peripheral blood volume and activity. The peak systolic pressure (PSP) by cuff method to end-systolic volume index (ESVI) relations showed good linearity (r greater than .930 in 84% of consecutive 50 cases) and were gentler in the groups with more impaired left ventricular function. Emax was related exponentially to ejection fraction (EF) and hyperbolically to end-diastolic volume index. The dead volume (VoI) was unfixed and fell into positive or negative value, and was not related to EF under control condition. PSP/ESVI in each loading condition was less variable with the alteration of blood pressure than EF. The linear relation was found between PSP/ESVI under control condition and Emax (PSP/ESVI = 0.651 . Emax + 0.958, r = 0.841, p less than .001). Thus in measuring ventricular volume, gated radionuclide angiocardiography is a non-invasive method less affected by the geometry of the left ventricle. Non-invasive determination of end-systolic pressure-volume relation using the volume by radionuclide and the blood pressure by cuff method is clinically useful in the assessment of left ventricular contractility.

Angiocardiography↗