Biomedical subjects

S Morimoto

Publications and source records attributed to S Morimoto.

At least 379 records · Page 21Linked to original sources

PubMed1991

Calcium metabolism in elderly hypertensive patients: possible participation of exaggerated sodium, calcium and phosphate excretion.

1. Renal handling of electrolytes, including calcium (Ca), in response to physiological saline infusion (20 mL/kg, i.v., for 2 h) as well as basal circulating levels of Ca-regulating hormones were compared in 27 hypertensive elderly females (mean age 80 +/- 9 years), in 44 normotensive elderly females (79 +/- 9 years) and in 19 young normotensive females (23 +/- 4 years). 2. The hypertensive elderly females showed excessive increase in urine volume and urinary excretions of sodium (Na), Ca and inorganic phosphate (P) in response to saline infusion, associated with slight but significant decrease in circulating levels of Na and ionized Ca compared with those in the other groups. These hypertensive elderly patients also showed characteristic features both in circulating blood pressure and Ca regulating factors; they showed significantly low levels of plasma renin activity and aldosterone concentration, significantly high plasma levels of atrial natriuretic peptide and noradrenalin, compared with those in young controls and normotensive elderly females. 3. Moreover they showed significant increase in basal serum levels of parathyroid hormone and 1,25-dihydroxyvitamin D, and significant decrease in basal serum levels of calcitonin, 25-hydroxyvitamin D and 24,25-dihydroxyvitamin D, compared with those in the other groups. 4. These results suggest that the exaggerated natriuresis associated with excessive loss of Ca and P in urine may participate in the abnormality of Ca metabolism in low-renin hypertensive elderly patients.

Adult↗

PubMed1991

Results of long-term rice bran treatment on stone recurrence in hypercalciuric patients.

A series of 182 calcium stone formers with idiopathic hypercalciuria underwent treatment with rice bran for 1 to 94 months. Urinary calcium excretion was considerably reduced, but there was some increase in urinary phosphate and oxalate. Urinary excretion of magnesium and uric acid, serum calcium, magnesium, phosphate, uric acid, parathyroid hormone (PTH) and ALP was unaffected. There were no obvious changes in serum iron, zinc and copper even when patients were treated for long periods. Rice bran was well tolerated in almost all cases and there were no serious side effects; 49 patients have undergone treatment for more than 3 years (average duration of administration 5.09 years). The frequency of new stone formation was drastically reduced (individual stone formation rate (no./year) from 0.720 +/- 0.533 to 0.125 +/- 0.204; group stone formation rate (no./patient-year) from 0.721 to 0.120) compared with the 3-year period before treatment. During treatment, 61.2% of patients remained in remission. Although rice bran therapy should be effective in correcting absorptive hypercalciuria, there may be limits to the overall ability of rice bran monotherapy to prevent recurrence.

Calcium↗

PubMed1991

Early asbestosis: evaluation with high-resolution CT.

To determine the earliest stage at which lesions in asbestosis can be diagnosed and to assess their progression, 23 asbestos-exposed patients with minimal or no abnormalities at plain radiography were examined with high-resolution computed tomography (HRCT) twice, with an interval of 12-37 months between examinations. In 21 of the patients, parenchymal abnormalities were found. Major parenchymal features seen at CT included thickened intralobular and interlobular lines, subpleural curvilinear lines, pleural-based nodular irregularities, hazy patches of increased attenuation, small cystic spaces, and small areas of low attenuation. At paired serial CT, subpleural isolated dots or branching structures connected with the most peripheral branch of the pulmonary artery started to appear in lower subpleural zones and then became confluent to create pleural-based nodular irregularities. CT-pathologic correlation led to the conclusion that the confluence of subpleural peribronchiolar fibrosis creates subpleural fibrosis.

Adult↗

PubMed1991

Increases in circulating level of platelet-activating factor lag behind transient neutropenia during hemodialysis with cuprophane membranes.

The significance of the level of circulating 1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphorylcholine (C16-PAF, platelet-activating factor) in relation to transient neutropenia during hemodialysis with cuprophane membranes was examined. The neutrophil count was transiently and significantly decreased at 30 min after the start of hemodialysis, and it then gradually recovered during the period from 60 to 240 min after the start. Mirror image changes were observed in the circulating levels of C3a and C5a, suggesting that the decrease in the neutrophil count was triggered by activation of the complement factors. The circulating level of C16-PAF, although being similar to the basal level after 30 min of hemodialysis, was significantly increased after 60 and 120 min of hemodialysis. These data indicate that the increase in the circulating PAF level is not a direct cause of the transient decrease in the neutrophil count, but may be the result of activated neutrophils during hemodialysis with cuprophane membranes.

Adult↗

PubMed1991

Exaggerated natri-calci-uresis and increased circulating levels of parathyroid hormone and 1,25-dihydroxyvitamin D in patients with senile hypertension.

Renal handling of Na and Ca in response to physiological saline infusion (20 ml/kg i.v. for 2 h) was compared between 27 hypertensive (mean +/- SD age 79.8 +/- 9.2 years) and 44 normotensive (79.1 +/- 4.1 years) senile females. Compared to the normotensive group, the hypertensive group showed statistically significant decreases in the basal values of serum Ca and PRA, and significant increases in basal circulating levels of parathyroid hormone and 1,25(OH)2D and in urinary excretions of Na, Ca and Pi in the 2-hour urine specimens during the saline infusion. These results suggest that the excessive excretions of Ca and Pi associated with exaggerated natriuresis may participate in aberration of Ca metabolism in low-renin hypertensive seniles.

Absorption↗

PubMed1991

Intracellular signal transduction evoked by low-density lipoprotein in vascular smooth muscle cells.

Low-density lipoprotein (LDL) is a well-known causal factor in the development of arteriosclerosis. In the present study, we evaluated LDL-evoked cellular signal transduction in cultured rat vascular smooth muscle cells (VSMC). The addition of LDL at concentrations of more than 50 ng/ml, and apolipoprotein B (Apo-B) at more than 5 ng/ml, induced rapid but transient increases in the inositol 1,4,5-trisphosphate (InsP3) level, and caused rapid phasic and subsequent tonic increases in cytosolic free Ca2+ concentration [( Ca2+]i) in a dose-dependent manner in VSMC. LDL and Apo-B also caused transient acidification followed by Na(+)-dependent and amiloride-sensitive alkalization of the cells due to stimulation of a Na+/H+ exchanger. The enhancement of thymidine incorporation induced by the addition of LDL correlated well with the degree of increment of [Ca2+]i increases by the lipoprotein. These results suggest that an increase in [Ca2+]i mediated by InsP3 and intracellular alkalization may function as an important signal for enhanced DNA synthesis induced by LDL in VSMC.

Amiloride↗

PubMed1991

Angiotensin II receptor and postreceptor events in adrenal glomerulosa cells from streptozotocin-induced diabetic rats with hypoaldosteronism.

Streptozotocin-induced chronic diabetic rats develop hyporeninemic hypoaldosteronism. The hypoaldosteronism is associated with selective unresponsiveness of aldosterone to angiotensin II (AII) and an atrophy of the zona glomerulosa. To assess the nature of the adrenal unresponsiveness to AII, we examined the [125I]monoiodoAII binding and the responses of pregnenolone formation and aldosterone production to AII using adrenal glomerulosa cells from diabetic rats 6 weeks after an injection of streptozotocin. Comparisons were made using the cells from control rats treated with vehicle. Diabetic rats had low levels of plasma renin activity, plasma 18-hydroxycorticosterone, and plasma aldosterone, and normal levels of plasma corticosterone and plasma potassium. The zona glomerulosa width was narrower in diabetic than in control rats. Scatchard analysis of the AII binding data demonstrated that the number and affinity of the receptors were similar in the cells from control and diabetic rats. When corrected to an uniform number of cells per group, baseline levels of pregnenolone formation and aldosterone production were similar in the cells from control and diabetic rats. However, cells from diabetic rats had a less sensitive and lower response of both pregnenolone formation and aldosterone production to AII. In contrast, the effect of ACTH on pregnenolone formation and aldosterone production was similar in the cells from control and diabetic rats. These results indicate that the main defect responsible for the hypoaldosteronism may be located on some step(s) mediating between AII receptors and conversion of cholesterol to pregnenolone, presumably on the calcium messenger system, with a disturbance downstream from AII binding.

Aldosterone↗

PubMed1991

Lack of enhanced responsiveness of plasma 18-hydroxycorticosterone and aldosterone to adrenocorticotropin as well as to angiotensin-II during moderate sodium depletion in type II diabetic subjects with normoreninemia.

Responses of plasma aldosterone (PA) and its precursor steroids to alpha ACTH-(1-24) (85.2 nmol, iv) injection and graded angiotensin-II (AII) infusions (3.90 and 7.80 pmol/kg.min for 30 min at each dose) on both 170 and 100 mmol sodium intakes were assessed in 25 type II diabetic subjects with normoreninemia and 11 age-matched normal subjects. The diabetic subjects and the normal subjects did not differ in mean blood pressure, serum electrolytes, and creatinine clearance, except for an increase in fasting plasma glucose (P less than 0.001) in the diabetic subjects. A 100-mmol sodium intake for 4 days produced an increase in basal plasma renin activity (P less than 0.01), plasma 18-hydroxycorticosterone (18-OHB; P less than 0.05), and PA (P less than 0.05), and a decrease in urinary sodium excretion (P less than 0.001) in the two groups. These parameters were similar in the two groups. ACTH injection produced significant increases in plasma cortisol, plasma corticosterone, plasma 18-OHB, and PA (P less than 0.005 or P less than 0.001), and graded AII infusions produced significant increases in plasma 18-OHB and PA (P less than 0.05 or P less than 0.01) during both 170- and 100-mmol sodium intakes in the two groups. In the diabetic subjects, however, the responses of plasma 18-OHB and PA to both ACTH injection and graded AII infusions on a 100-mmol, but not on a 170-mmol, sodium intake were subnormal (P less than 0.05 or P less than 0.01) and were similar to those on a 170-mmol sodium intake. These results indicate a lack of enhanced responsiveness of plasma 18-OHB and PA to both ACTH and AII during moderate sodium restriction in nonazotemic type II diabetic subjects with normoreninemia. It appears that these subjects have selective unresponsiveness of adrenal zona glomerulosa to sodium depletion per se, but not to ACTH or AII.

18-Hydroxycorticosterone↗

PubMed1991

Novel 1,4-dihydropyridine calcium antagonists. II. Synthesis and antihypertensive activity of 3-[4-(substituted amino)phenylalkyl]ester derivatives.

Novel 1,4-dihydropyridine derivatives bearing 3-[4-(substituted amino)phenylalkyl]ester side chains were prepared and tested for their antihypertensive activity in spontaneously hypertensive rats. Most compounds showed a more potent antihypertensive effect and a longer duration of action than nicardipine. The derivatives with a benzhydrylpiperazinyl and a benzhydrylpiperidinyl group were distinctive. 2-[4-(4-Benzhydryl-1-piperazinyl)phenyl]ethyl methyl 1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,5-pyridinedicarboxylate (4e), its 4-(4-cyano-2-pyridyl) analogue (4f), its 3-[4-(4-benzhydryl-1-piperazinyl)phenyl]propyl ester analogue (4h), its 2-[4-(4-benzhydryl-1-piperidinyl)phenyl]ethyl ester analogue (4j), and its 2-[4-(1-benzhydryl-4-piperidinyl)phenyl]ethyl ester analogue (4k) were selected as candidates for further pharmacological investigations.

Animals↗

PubMed1991

Carcinoma of the esophagus: CT vs MR imaging in determining resectability.

MR imaging and CT were performed prospectively in 35 patients with esophageal carcinoma to determine the resectability of the primary tumors, because at our institution patients with resectable tumors have surgery regardless of the presence of distant metastases. Tumors with evidence of aortic or tracheobronchial invasion on MR or CT were considered to be unresectable. Tracheobronchial invasion was diagnosed when the tumor extended into the lumen of the airway, and aortic invasion was diagnosed when the triangular fat space between the esophagus, aorta, and spine adjacent to the primary tumor was obliterated. Two patients were excluded because of suboptimal MR images produced by motion artifacts. Pathologic proof was obtained from either surgery or autopsy in 31 patients. Of these, six patients (19%) had proved unresectable tumors (three aortic invasion and three tracheobronchial invasion). In all six cases, these features were correctly detected with both MR and CT. One patient had false-positive findings on MR and CT. An indeterminate diagnosis was obtained with MR in three patients and with CT in four patients. These incorrect or indeterminate results were all related to the diagnosis of aortic invasion. No patient had a false-negative result. When indeterminate diagnoses were considered false-positive, sensitivity, specificity, and accuracy for resectability were 100%, 84%, and 87%, respectively, for MR and 100%, 80%, and 84%, respectively, for CT. We conclude that MR and CT have nearly the same accuracy in predicting resectability of tumors in patients with esophageal carcinoma.

Adenocarcinoma↗

PubMed1991

Circadian rhythm of blood pressure in normotensive NIDDM subjects. Its relationship to microvascular complications.

OBJECTIVE: To investigate the relationship between circadian rhythm of mean blood pressure (MBP) and microvascular complications in non-insulin-dependent diabetes mellitus (NIDDM) subjects. RESEARCH DESIGN AND METHODS: Seventy-six normotensive NIDDM subjects without azotemia were studied under ordinary hospital conditions with a noninvasive ambulatory blood pressure monitoring device. Time series data were analyzed by the cosinor method. RESULTS: Fifty-four subjects had a circadian MBP rhythm similar to that of 34 age-matched nondiabetic control subjects, with a peak value in the afternoon (group 1). In contrast, 22 had a reversed circadian MBP rhythm, with a peak value during the night (group 2). Obvious complications were found in 65% of group 1 and in all of group 2. The prevalence of retinopathy and somatic neuropathy and the degree of retinopathy were similar in the two groups. The prevalence and degree of autonomic neuropathy (postural hypotension and reduced beat-to-beat heart-rate variation) and nephropathy were greater in group 2 than group 1. Linear discriminant analysis revealed a correlation between the reversed circadian MBP rhythm and postural hypotension (F = 32.2, P less than 0.001) and overt nephropathy (F = 5.1, P less than 0.05) but not with beat-to-beat heart-rate variation (F = 0.17, NS). CONCLUSIONS: These results suggest that in the hospitalized normotensive NIDDM subjects, there are normal and reversed circadian MBP rhythms and that the reversal of normal circadian MBP rhythm may be related to the degree of postural hypotension and/or nephropathy.

Blood Glucose↗

PubMed1991

[Cognitive function and calcium-related factors in elderly female subjects].

Calcium (Ca)-related factors were evaluated as possible related factors to senile dementia in 60 elderly female subjects (mean age +/- SD: 79 +/- 7 years). These subjects were classified by their score on Hasegawa's Dementia Screening Scale, into a non-dementia group (score 22-32.5, n = 18) and a dementia group (0-21.5, n = 42), and the latter group was further classified by ischemic score into Alzheimer-type dementia (n = 22) and vascular-type dementia (n = 20). There was no significant difference in the mean values of age or serum creatinine among the three groups. In the Alzheimer-type dementia group, the mean serum level of Ca was significantly lower, and the serum level of parathyroid hormone (PTH) and urinary Ca were significantly higher than those in the non-dementia group, respectively. In the group of vascular-type dementia, the mean serum level of calcitonin (CT) was slightly, but not significantly, lower than that in the non-dementia group. The score for cognitive subjects negatively correlated significantly with the values of serum PTH (r = -0.49, p less than 0.05) and urinary Ca excretion (r = -0.38, p less than 0.05), respectively, and positively correlated significantly with that of serum 1,25-dihydroxyvitamin D [1,25(OH)2D] (r = 0.31, p less than 0.05), in the combined group of non-dementia and Alzheimer-type dementia, and positively correlated significantly with the serum CT level (r = 0.40, p less than 0.05) in the combined group of non-dementia and vascular-type dementia.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1991

[Presence of circulating suppressive factor for muscarinic acetylcholine receptor in senile dementia].

Alzheimer's disease is one of the main causes of senile dementia. Although its pathogenesis is not clear, some evidence has revealed that the activity of acetylcholine receptor in the brains of these patients is decreased. In the present study, possible circulating factors, affecting the muscarinic acetylcholine receptor of the synaptic vesicle from the rat brain, were evaluated in the serum of 95 senile subjects (34 males and 61 females, mean +/- SD age of 77.5 +/- 8.6 years). The cognitive function of these subjects was assessed by their Mini-Mental State scores, and they subjects were divided into non-dementic-subjects with a score of 21 or more, or subjects with dementia with a score of 20 or less. The latter were further divided into senile dementia with Alzheimer type (SDAT) and vascular type dementia (VS) using Hatchinski's ischemic score. The mean suppression rate by the serum from the SDAT patients on the binding of tritiated quinuclidinyl benzilate (3H-QNB), an antagonist for muscarinic acetylcholine receptor, to the rat synaptic membrane, was 18.1 +/- 7.2% of the control value, which was significantly greater than that of the non-dementic subjects, (4.7 +/- 3.8%). However, that in the VD group (8.4 +/- 6.8%), was not significantly different from the control value. Moreover the suppression rate of the serum on 3H-QNB binding showed significant positive correlated with score for the Mini-Mental State (r = 0.480, p less than 0.01) in the SDAT group. These data support the hypothesis that circulating suppression factors may participate in the pathogenesis of SDAT.

Aged↗

PubMed1991

[The influence of aging on parathyroid hormone-induced enhancement in (Ca2+ + Mg2+)-ATPase activity of rabbit renal basolateral membrane].

We studied the influence of aging on the stimulatory effect of parathyroid hormone (PTH) to (Ca2+ + Mg2+)-ATPase activity of rabbit renal basolateral membrane (BLM). Stimulated by PTH, (Ca2+ + Mg2+)-ATPase activity of BLM from aged rabbits was lower than those from young rabbits. However, the stimulatory effect of cyclic AMP (cAMP) showed no differences in terms of (Ca2+ + Mg2+)-ATPase activity in BLM from aged and young rabbits. As cAMP production in BLM caused by PTH stimulation was not measured, it is unclear whether cAMP production is different in BLM from young and aged rabbits. From these results, we concluded that in BLM from aged rabbit, the lower effect of PTH on (Ca2+ + Mg2+)-ATPase is due to lower production of cAMP or some other disorder of the PTH signal transduction mechanism. As (Ca2+ + Mg2+)-pump plays an important role in Ca2+ reabsorption in kidney, its lower activity in aged rabbit may be one reason for aberration of renal calcium handling.

Aging↗

PubMed1991

[An enzymatic determination of serum citrate with citrate lyase].

A method for the enzymatic determination of the serum citrate using citrate lyase is described. The optimum pH was equal to or higher than 8.6. Prior to the determination of the serum citrate, the samples were deproteinized with perchloric acid. After the precipitation of the proteins, potassium hydroxide was added under an ice-cooling condition in order to neutralize the solution. The recovery rates of the citrate added to serum ranged from 92% to 108%, and the coefficient of variation of triplicate assay was 4.2%. The mean serum value of 17 healthy subjects was 1.57 mg/dl, with a range of 1.03-2.03 mg/dl. In seven healthy subjects, 3 g of sodium-potassium citrate was administered orally and the serum citrate was measured 0, 15, 30, 45, 60, and 120 min later. The serum citrate was significantly increased in the periods between 15 and 60 min.

Adult↗

PubMed1991

Initial appearance of an ill-defined shadow on a chest roentgenogram in a patient with aortitis syndrome.

A 20-years-old woman with fever and an abnormal shadow on a chest roentgenogram was admitted to our hospital. High grade fever continued even after gradual disappearance of the ill-defined shadow on the right upper lobe (S3) with minor fissure deviation upward, while neck pain and bruit gradually developed. She was diagnosed as aortitis syndrome from a digital subtraction angiography. The initial appearance of an ill-defined shadow on a chest roentgenogram, considered as pulmonary infarction, is rare in the aortitis syndrome and this kind of onset is interesting in relation to the pathogenesis and diagnosis of this syndrome.

Angiography, Digital Subtraction↗

PubMed1991

Bradykinin suppresses endothelin-induced contraction of coronary artery through its B2-receptor on the endothelium.

Bradykinin (BK), a powerful vasodilating peptide, has been known to be one of the factors regulating vascular contractility mainly through its action on the endothelium. The effects of BK on vascular contraction induced by endothelin-1 (ET-1), a potent vasoconstrictor peptide produced in endothelium, were investigated in vitro using the canine coronary ringed artery. ET-1 at concentrations of 10(-10) to 10(-7) M induced strong and persistent contraction dose-dependently. The ET-1-induced contraction was inhibited by BK at concentrations of 10(-7) and 10(-6) M only in the presence of endothelium. A B1-receptor agonist (des-Arg9-BK) and a B1-receptor antagonist (des-Arg9-[Leu8]-BK) did not affect these effects of BK, whereas a B2-receptor antagonist ([D-Arg0,Hyp3,Thi5,8,D-Phe7]-BK) inhibited the effect of BK on the ET-1-induced contraction. These results indicate that BK may be a potent counter-factor for the ET-1-induced coronary vasoconstriction through its B2-receptors on the endothelium.

Animals↗

PubMed1991

CT findings of endobronchial metastasis.

One hundred and sixty-one patients with pulmonary metastases were studied with CT. Six of them proved to have endobronchial (intraluminal) metastatic lesions by bronchoscopy. Retrospective analysis of the CT studies showed obstruction and/or narrowing of the bronchi in 5 cases while no lesion was observed in one patient. Although CT can not always demonstrate intraluminal lesions, it should be performed when an endobronchial metastasis from extrathoracic malignancy is seen by bronchoscopy because it will show hilar or mediastinal lymphadenopathy, or single or multiple pulmonary metastases other than the endobronchial lesion.

Adult↗