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Biomedical subjects

M Inada

Publications and source records attributed to M Inada.

At least 271 records · Page 15Linked to original sources
PubMed1989

Factors associated with persistent and transient fascicular blocks in anterior wall acute myocardial infarction.

To determine the factors associated with persistent and transient fascicular blocks, 144 patients with Q-wave anterior wall acute myocardial infarction (AMI) were studied. Thirty-three patients had new onset of fascicular block considered to be a consequence of AMI. Multivariate analysis using 16 clinical variables revealed that the number of asynergic segments, serum potassium level and pericardial rub were significant factors related to the occurrence of fascicular block. Among the 33 patients with fascicular block, 18 had persistent (group 1) and 15 had transient (group 2) fascicular blocks. When the 2 groups with fascicular block were compared, group 1 had significantly more asynergic segments than group 2 (4.7 +/- 1.2 vs 3.7 +/- 1.6, respectively), whereas pericardial rubs were observed significantly more in group 2 (67%) than in group 1 (28%). Therefore, the inflammatory process of AMI was 1 of the mechanisms related to the occurrence of a transient fascicular block and a more extensive myocardial necrosis was associated with a persistent fascicular block.

Aged↗
PubMed1989

Simultaneous measurement of alpha-human atrial natriuretic factor (hANF) and NH2-terminal fragment of pro-hANF in essential hypertension.

A radioimmunoassay specific for the N-terminal fragment of prohuman atrial natriuretic factor (hANF) was established with the use of antiserum for pro-hANF (1-30). Plasma levels of alpha-hANF-like immunoreactivity (LI) and pro-hANF (1-30)-Ll in patients with severe hypertension who were receiving a normal sodium diet were 56 +/- 5 pg/ml and 2710 +/- 118 pg/ml, respectively; these levels were significantly higher than control values. Levels of these peptides in patients with mild hypertension were similar to those of control subjects. Mean blood pressure correlated closely with alpha-hANF-Ll levels (r = 0.56, p less than 0.001) and pro-hANF (1-30)-Ll levels (r = 0.66, p less than 0.001) in patients receiving a normal sodium diet. Plasma alpha-hANF-Ll and pro-hANF (1-30)-Ll levels were significantly decreased 3 days in mild hypertension and 7 days in severe hypertension after initiation of a low-sodium diet with a decrease in blood pressure as compared to the initial values. These results suggest that plasma N-terminal fragment levels are elevated in proportion to the degree of hypertension, and they can be reduced by means of effective antihypertensive treatment.

Adult↗
PubMed1989

Effect of coenzyme Q10 on hemodynamic response to ocular timolol.

Coenzyme Q10 (CoQ10) is an essential component of the mitochondrial membrane and plays an important role in the maintenance of normal cardiac function. To evaluate the effects of ocular timolol on the cardiovascular system and determine the protective effect of CoQ10, 16 patients with glaucoma were studied using impedance cardiography. Following instillation of 1 mg timolol maleate in each eye, heart rate (HR) and stroke index (SI) decreased, and total peripheral resistance index (TPRI) increased significantly. Reexamination was performed after 6 weeks of 90 mg oral CoQ10. Despite decreases in HR, percent changes in HR were significantly less after CoQ10 at 120 min. Stroke index showed an initial increase which was not observed without CoQ10. These data suggest that CoQ10 delayed the appearance of inotropic blockade of timolol and hastened the disappearance of chronotropic blockade. Additional study of six normal volunteers with 6 weeks of oral CoQ10 showed a similar decrease of intraocular pressure after timolol instillation as compared to those without CoQ10. Thus, administration of oral CoQ10 in patients receiving ocular timolol may be useful in mitigating cardiovascular side effects without affecting intraocular pressure in the treatment of glaucoma.

Administration, Oral↗
PubMed1989

Absent effect of plasma vasopressin on rat brain blood flow during hemorrhage.

We investigated whether a reflex increase in plasma vasopressin level due to hemorrhagic hypotension affects brain blood flow. In 60 lightly anesthetized, artificially ventilated rats, the flow was determined with radiolabeled microspheres. We found excellent maintenance of blood flow throughout all brain regions during the hypotensive state (71 mmHg on average), and such maintenance of flow was not modulated at all by a supramaximal intravenous dose of the selective vasopressin V1-receptor antagonist [d(CH2)5 Tyr-(Me)]AVP. The latter finding also implies that the V1 antagonist failed to unmask the vasodilator type actions of V2 receptors on the maintenance of flow during hemorrhagic hypotension. These were true also when the cervical sympathetic bundles were severed bilaterally. The plasma level of endogenous vasopressin was increased during hypotension, ranging from 118 to 973 pg/ml. Despite this increase, the brain blood flow was entirely independent of the plasma vasopressin level in all the brain regions studied. We conclude that the brain circulation of rats can maintain its blood flow during hemorrhagic hypotension without any apparent contribution from a concomitant reflex increase in plasma vasopressin. Despite our negative results for the brain blood flow, the possible segmental effects of circulating vasopressin on the brain arterial caliber remain to be clarified under conditions of hemorrhagic hypotension.

Animals↗
PubMed1989

Thyroid-stimulating activity in sera of normal pregnant women.

To evaluate the effect of a thyroid stimulator on thyroid function in the sera of normal pregnant women, we measured thyroid-stimulating activity (TSA) using a highly sensitive bioassay based on cAMP accumulation in cultured rat FRTL-5 thyroid cells. Serum was pretreated with 10% polyethylene glycol (PEG), and the supernatant (PEG-pretreated serum) was then used in the following studies. FRTL-5 cells were preincubated in 5H medium and incubated for 2 h with PEG pretreated serum, and cAMP was measured. All 11 patients with untreated hyperthyroid Graves' disease with strongly positive thyroid-stimulating antibody activity had normal TSA, because only 5.6% of their immunoglobulin G was recovered in the PEG-pretreated serum. In 32 normal pregnant women, 29 (91%) had positive TSA. Their TSA showed statistically significant positive correlations with serum hCG and free T4 levels, and a negative correlation with serum TSH levels. Moreover, when hCG was absorbed from sera by incubation with the solid phase anti-HCG monoclonal antibody, a significant positive correlation was observed between the rate of decrease in hCG and that in TSA. In conclusion, 1) TSA exists in the sera of normal pregnant women, which reflects hCG itself; and 2) thyroid glands of normal pregnant women may be stimulated by TSA to induce a slight suppression of TSH but not sufficient to induce overt hyperthyroidism.

Adult↗
PubMed1989

Relationship between the coronary diameter and occurrence of vasospastic angina in patients with normal coronary arteries.

Coronary artery diameters were measured after various interventions in 30 patients without angina pectoris (group 1) and in 15 with angina pectoris (group 2: rest, or rest and effort angina) who had normal coronary arteries. The coronary artery diameters were significantly smaller in many coronary segments in group 2 than in group 1 during a control state, after exercise and ergonovine, but became nearly identical after isosorbide dinitrate in both groups. Patients in group 1 had diffuse narrowing but no focal vasoconstriction after ergonovine and all the segments had a diameter of more than 50% of that after isosorbide dinitrate. The change of coronary artery diameter in group 2 patients who had no vasospasm by ergonovine was the same as that in group 1. Patients in whom vasospastic angina was induced had local vasoconstriction or severe diffuse narrowing (less than 45%). These results indicate that angina pectoris patients with normal coronary arteries had an acceleration of coronary arterial basal tone, but vasospastic angina pectoris was not induced just by the general response of the coronary artery to various interventions in addition to the accentuated basal tone. For vasospastic angina to occur, local abnormal response to various interventions must be present.

Adult↗
PubMed1989

Cytoprotective effect of plasmin inhibitor on necrotizing agent-induced gastric lesions in rats.

We studied the effect of plasmin inhibitor on ethanol and ammonia-induced gastric mucosal lesions in rats using an ex vivo chamber. Tranexamic acid and aminocaproic acid significantly inhibited macroscopic gastric hemorrhagic necrosis and attenuated the decrease of gastric transmucosal potential difference induced by 50% ethanol and 1% ammonia. The protection of gastric mucosa afforded by tranexamic acid and aminocaproic acid was not affected by pretreatment with indomethacin (5 mg/kg). These results suggest that plasmin inhibitor plays an important role in the prevention of gastric deep necrosis following exposure of the stomach to a damaging agent.

Aminocaproic Acid↗
PubMed1989

Effects of ammonia on the gastric mucosal barrier in rats and dogs.

We examined the effect of ammonia on the gastric mucosal barrier by measuring the changes in transmucosal fluxes of H+, Na+ and K+. In rats, ammonia at concentrations of 0.1 to 0.5% increased the H+ loss from the lumen and 0.2 to 0.5% concentrations of ammonia increased both Na+ and K+ influxes into the lumen. In dogs, in an exactly similar manner to rats, ammonia at concentrations of 0.1 to 0.5% increased H+ loss, and ammonia at concentration of 0.5% increased both Na+ and K+ influxes into the lumen. These results suggest that ammonia breaks the gastric mucosal barrier.

Ammonia↗
PubMed1989

Diastolic time during low-level exercise in the late phase of hospitalization for acute myocardial infarction.

To evaluate DT during a low-level exercise test, the relation between DT and heart rate was studied by ear densitography in the late phase of hospitalization for acute MI. None of the patients had an ischemic electrocardiographic response. The patients were divided into two groups: group 1 was comprised of nine patients with a resting left ventricular end-diastolic volume of 140 ml or more, and group 2 was comprised of nine patients with a left ventricular end-diastolic volume less than 140 ml. The QS2 and heart rate had an linear inverse relation during exercise, and DT and heart rate had an nonlinear inverse relation (DT = e(7.27-0.0166 x heart rate) and DT = e(7.11-0.0142 x heart rate) for groups 1 and 2, respectively). Significant prolongation of the QS2 with consequent shortening of DT (p less than 0.05) was observed in group 1. Thus, in addition to a larger decrease in DT with a small change in heart rate, particularly during low-level exercise, patients with increased left ventricular end-diastolic volume have a potential for initiating subendocardial ischemia which results in further prolongation of systole and, hence, greater abbreviation of DT.

Blood Pressure↗
PubMed1989

Activity of thyroid stimulating antibody and thyroid stimulation blocking antibody determined by radioiodine uptake into FRTL-5 cells.

To investigate the pathophysiology of patients with autoimmune thyroid diseases, we measured serum thyroid stimulating antibody (TSAb) activity and thyroid stimulation blocking antibody (TSBAb) activity by determining the radioiodine (125I) uptake into FRTL-5 cells. FRTL-5 cells were pre-incubated for seven days with 5H medium and then incubated for 48 hours with patients' crude IgG prepared by polyethylene glycol precipitation. In order to measure TSBAb, 10 microU/ml TSH was also added. 125I was added one hour before the end of the 48 hour incubation period. After the incubation, the medium was aspirated, and the radioactivity in the cells was counted. In patients with untreated hyperthyroid Graves' disease, TSAb was detectable in 18 of 20 patients, the detectability being 90%, and activity showed a statistically significant positive correlation with TSAb activity determined by c-AMP accumulation. Out of 41 patients with hypothyroidism, TSBAb determined by 125I uptake was positive in six cases, the detectability being 14.6%. The inhibition of 125I uptake by one of these six IgGs was suggested to be at the TSH receptor level because it inhibited TSH induced c-AMP accumulation and showed positive thyrotropin binding inhibitor immunoglobulin (TBI I) activity, but did not inhibit the forskolin- and (Bu)2cAMP-induced 125I uptake. Inhibition of another IgG was suggested at the post-receptor level because it did not inhibit TSH induced cAMP accumulation and showed negative TBI I activity, but inhibited forskolin- and (Bu)2cAMP-induced 125I uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

A sensitive and practical bioassay for thyrotropin using cultured FRTL-5 cells: assessment of bioactivity for serum TSH in patients with chronic renal failure.

A sensitive bioassay for TSH employing a practical extraction method was developed, and the bioactivities in patients with chronic renal failure receiving hemodialysis were compared with those in normal subjects. Serum samples were obtained from 12 normal subjects and 12 patients with chronic renal failure receiving hemodialysis. TSH was extracted from the serum using anti-human TSH monoclonal antibody coated tubes, followed by elution with 2.0 mol/l guanidine-HC1 solution (pH 3.2). After the eluate had been dialyzed against phosphate buffered saline (pH 7.4) and again against TRIS-HC1 solution (pH 7.4) and then lyophilized, it was reconstituted with hypotonic Hanks' solution. Bioassay for TSH was performed by measuring the levels of cAMP released into the medium from cultured FRTL-5 cells incubated with the extract. The mean immunoreactive recovery rates of TSH from the serum in normal subjects and patients with chronic renal failure were about 42% (+/- 6) and 40% (+/- 2), respectively. The present bioassay was sufficiently sensitive to detect a serum TSH level of 1.0 mU/l when 3.0 ml of serum was used. Extracts from standard sera at concentrations ranging from 1.0 to 10 mU/l added to the culture medium caused significant linear increases in cAMP production. Based on analysis of covariance the regression line between the immunoreactivities and bioactivities of serum TSH in patients with chronic renal failure (y = 0.90x + 0.3, r = 0.92) was not significantly different from that in normal subjects (y = 1.04x + 0.1, r = 0.93).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Left ventricular regional function after acute anterior myocardial infarction in diabetic patients.

To elucidate the pathophysiological role of diabetes mellitus in determining the left ventricular regional function of the noninfarcted area, 55 patients with acute Q wave anterior myocardial infarction (MI) were studied. The regional ejection fraction of the noninfarcted area was obtained by radionuclide angiocardiography and was used to estimate the left ventricular regional function of the noninfarcted area. Multiple regression analysis was performed to determine the important variables contributing to the regional ejection fraction based on 10 clinical variables: age, sex, QRS score, diabetes mellitus, hypertension, smoking, postinfarction angina, body mass index, serum cholesterol, and coronary atherosclerosis. A high QRS score (P less than .001) and the association of diabetes mellitus (P less than .05) were the important factors contributing to regional left ventricular dysfunction. The regional ejection fraction and QRS score had an inverse linear relationship in the diabetic and nondiabetic groups, and the regional ejection fraction was significantly lower in diabetic patients at every QRS score (P less than .05). The association of hypertension, severity of coronary atherosclerosis, serum cholesterol level, age, and body mass index did not differ between diabetic and nondiabetic patients, which indicates that diabetes mellitus was not mediated through these atherogenic traits. Thus, diabetes mellitus is another discrete cause of regional left ventricular dysfunction of the noninfarcted area after acute MI.

Diabetes Mellitus, Type 2↗
PubMed1989

[Biomechanical study on the mechanism of the mandibular condylar fracture. 1].

The condylar process is one of the sites predisposed to fracture clinical and experimental studies on the fracture mechanism have so far been undertaken by a number of our predecessor. However, the difference in the fracture mechanisms of intracapsular and extracapsular fracture has not completely been determined yet. In a Japanese Journal of Oral and Maxillofacial Surgery: Vol.32, 1362-1381, 1986: Shimada have previously reported the strong possibility that the direction and extend of fracture lines in the fracture of condylar process were influenced by the morphological characteristics of the condylar head. In order to verify this postulation, stress distribution patterns by the cross-sectional morphology of various types of condylar heads were investigated by two-dimensional finite element method, using 15 Indian edentulous mandibles. In this analysis, loading was applied to three directions in the model of the mandibular body, and two directions in the model of the mandibular head. The results indicated the following something. 1) With the loading in the direction of condylar head from mandibular angle, compressed stress arose on the condylar head with the surface. And with the loading in the direction of condylar head from chin and mandibular body, tugged stress arose on the condylar neck. 2) With the loading in the direction of vertical, these were conjectured that comminuted fracture arose on convex type, sagittal fracture arose on concave type and a style midway fracture arose on straight type. 3) With the loading in the direction of lateral, these were conjectured that fracture of condylar neck arose on the three types, especially the tendency was remarkable on straight type.

Biomechanical Phenomena↗
PubMed1989

[Evaluation of the laser-Doppler velocimetry method in the measurement of gastric blood flow in rats--spatial resolution].

In this paper, gastric blood flow in rats was measured with the laser-Doppler velocimetry method (the LDV method) to study about the tissue locus where its flow signal arises (spatial resolution). In the measurement throughout some 1 mm thickness of another nonperfused gastric wall interposed between the laser probe and gastric mucosal surface, its laser flow signal was 17% of the flow signal in the usual measurement. In the blood flow measurement with the LDV prove on the mucosal and the serosal surface of gastric wall, the laser flow signal on the mucosal surface was higher (p less than 0.05) than that on the serosal surface. These results suggested that the laser flow signal mainly arose from the tissue right under the laser probe, reflecting the total gastric blood flow of the gastric wall. In the regional blood flow measurement at corpus and antrum, the ratio between antral and corpus flow signals by the LDV method was similar to that between gastric mucosal blood flows at both sites by the hydrogen gas clearance technique. In the blood flow measurement after the intravenous infusion of each pentagastrin, isoproterenol, and vasopressin, flow signal of the LDV method could detect the each effect of these drugs on gastric mucosal blood flow as well as well as the hydrogen gas clearance technique. These results showed that the laser flow signal and gastric mucosal blood flow were mutually correlated.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Platelet vasopressin receptor in patients with chronic renal failure.

The vasopressin binding to intact platelet from patients with chronic renal failure (CRF) was investigated in relation to the abnormalities in platelet aggregation. The immunoreactive arginine vasopressin (AVP) in platelet-free plasma (PFP) but not in platelets was significantly higher in non-dialyzed patients with CRF than in normal subjects. Binding studies using [3H]AVP demonstrated a decreased number of binding sites (Bmax) on platelets from patients with CRF compared to normal controls with no significant difference in affinity (Ka). A significant diminution of the maximal percentage aggregation with AVP was found in patients with CRF. An inverse relation between Bmax and the PFP AVP levels and a highly significant relation between Bmax and the maximal percentage aggregation with AVP in patients with CRF and normal controls were observed. At 4 weeks after the introduction of hemodialysis in patients with CRF, the PFP AVP levels decreased and Bmax increased significantly, and the maximal percentage aggregation tended to increase. The present findings suggest that a reduced number of AVP receptors on platelets might account for decreased platelet aggregation with AVP, and the elevated plasma AVP levels might induce a down-regulation of the AVP receptor number on platelets in patients with CRF.

Adult↗
PubMed1989

[Clinical significance of the technetium-99m/thallium-201 overlap in acute myocardial infarction].

The region of overlap of thallium-201 (Tl) and technetium-99m pyrophosphate (Tc) was evaluated as a scintigraphic prognosticator of future necrosis. Serial time courses of myocardial perfusion according to Tl and left ventricular wall motion evaluated by two-dimensional echocardiography (2D echo) were used in 22 patients. In all, dual energy emission computed tomography (dual-SPECT) showed the Tl/Tc overlap on identical slices on the third post-infarction day. According to the results of dual-SPECT, the patients were categorized in three groups: nine with large Tl/Tc overlap (group A); five with small Tc accumulation and small Tl/Tc overlap (group B); and eight with large Tl defect and Tc accumulation, which are concordant with each other (group C). Tl-201 SPECT and 2D echo were attempted serially on the 1st and 2nd days, the 7th-10th days and the 28th-30th days. To estimate infarct size with Tl-201 SPECT, we measured pixel counts of eight short-axis images with the 40% cut-off level and computed "% defect". To evaluate the viability of the myocardium, "% Tl uptake" was computed from the ROIs both in the centers of the infarct areas and their border zones. 2D echoes of the left ventricular short axis at the chordae tendineae level were recorded to identify the time course of percent fractional area change (% FAC) of the ischemic left ventricular wall. The scintigraphic results were compared with the serial changes of regional ejection fraction in the areas of infarcts and ischemic lesions. The % defect remained unchanged in group C (29.2 +/- 11.5----25.7 +/- 8.3%); whereas those of groups A and B decreased significantly (21.2 +/- 11.3----9.9 +/- 6.3%, 13.8 +/- 2.6----5.4 +/- 2.9%, respectively). In groups A and B, % FAC improved significantly in the centers of the infarct areas and the border zones, but not in group C. Exercise-induced ischemia determined by redistribution of Tl at the chronic phase was observed more frequently in groups A and B than in group C. These findings indicated that more myocardium can be saved from necrosis in group A than in group C. In conclusion, it is suggested that there is considerable viable myocardium in patients with large Tl/Tc overlap on dual-SPECT.

Aged↗
PubMed1989

[Effect of isometric hand-grip exercise on left ventricular diastolic filling in patients with effort angina: a pulsed Doppler echocardiographic study].

To detect myocardial ischemia and to estimate cardiac reserve in patients with effort angina pectoris without history of myocardial infarction, left ventricular diastolic filling was measured using Doppler echocardiography during isometric handgrip exercise. Nineteen patients with effort angina pectoris undergoing coronary angiography and 16 normal subjects were studied. The angina patients were categorized in two groups: 12 with single vessel disease (SVD) and seven with multiple vessel disease (MVD). Fifty percent maximum voluntary contraction isometric handgrip exercise was performed for two minutes. 1. The resting A/R in the angina group was significantly greater than that of the normal subjects (SVD: 1.20 +/- 0.24, MVD: 1.21 +/- 0.27, normal 0.85 +/- 0.10) (p less than 0.001). However, the values of many cases in these three groups overlapped. 2. In SVD, the A/R increased significantly during isometric handgrip exercise (1.20 +/- 0.24 to 1.96 +/- 0.66: p less than 0.001). The delta A/R (0.76 +/- 0.15) was significantly greater than that of patients in other groups (MVD: 0.10 +/- 0.13, normal: 0.09 +/- 0.01) (p less than 0.001). Consequently, the A/R after exercise clearly distinguished the SVD from the normal subjects. 3. In MVD, the A/R did not change significantly during exercise (1.21 +/- 0.27 to 1.31 +/- 0.41), and there were no significant differences in delta A/R as compared to the normal subjects (p less than 0.01). The A/R decreased during exercise in three of the seven patients, and this was markedly different from that of the normal subjects. These findings suggest that assessment of changes in left ventricular diastolic filling during isometric handgrip exercise is useful in detecting myocardial ischemia and in estimating cardiac reserve in patients with effort angina pectoris.

Adult↗