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Biomedical subjects

H Mashiba

Publications and source records attributed to H Mashiba.

At least 91 records · Page 5Linked to original sources
PubMed1992

Evaluation of thyroid function in patients with isolated adrenocorticotropin deficiency.

Thyroid hormone and thyrotropin (TSH) levels were evaluated before and after adrenal replacement in eight patients (six men and two women, 35-62 years old) with isolated adrenocorticotropin (ACTH) deficiency. Six patients (cases 1-6) showed TSH excess before treatment. Four patients (cases 1-4), who initially had subnormal thyroid hormone levels, showed resolution of biochemical features of primary hypothyroidism after treatment, although TSH excess has persisted in two patients (cases 1 and 2). Case 1 had an extremely high titer of antimicrosomal antibody (MCHA), and cases 2 and 3 showed histologically and cytologically chronic thyroiditis, despite negative results for MCHA and antithyroglobulin antibody, respectively. Two patients (cases 5 and 6), who had had normal thyroid hormone levels and did not show the significant rise in serum T3 in TSH releasing hormone testing, showed TSH normalization without changes in serum thyroid hormone levels after treatment. The other two patients (cases 7 and 8), who initially had normal TSH and thyroid hormone levels, did not show the significant changes in serum TSH and thyroid hormone levels after treatment. The prevalence of chronic thyroiditis coexistence in isolated ACTH deficiency may be higher than predicted. Therefore, TSH excess before adrenal replacement may be attributed to not only direct enhancement of TSH release due to chronic cortisol deficiency but also to thyroid dysfunction due to chronic thyroiditis. It is possible that hypothyroidism due to chronic thyroiditis can be improved only by adrenal supplementation.

Adrenocorticotropic Hormone↗
PubMed1992

Effect of alacepril on blood pressure and neurohumoral factors at rest and during dynamic exercise in patients with essential hypertension.

We assessed blood pressure and neurohumoral factors at rest and during exercise in 10 patients with essential hypertension before and after treatment with the new angiotensin converting enzyme inhibitor, alacepril (25-50 mg day-1). Alacepril significantly lowered mean blood pressure at rest and at the same exercise load as before treatment without affecting heart rate response. The response of plasma renin activity, plasma aldosterone, and plasma adrenaline were not changed by alacepril, but increase of plasma angiotensin II and plasma noradrenaline during exercise were significantly attenuated after alacepril treatment (ANOVA, P = 0.04, both). The change in mean blood pressure during exercise was positively correlated with the decrease in plasma angiotensin II (r = 0.65, P < 0.05). These results demonstrated that alacepril was effective in essential hypertension both at rest and during exercise, suggesting that the antihypertensive effect during exercise might be related to the decrease in pressor hormones, especially in plasma angiotensin II.

Adult↗
PubMed1992

Detection of thyroid-stimulating antibody in patients with inflammatory thyrotoxicosis.

The detection of thyrotropin-binding inhibitory immunoglobulins (TBII) and/or thyroid-stimulating antibody (TSAb) has been reported in some patients with painless thyroiditis (PT) or subacute thyroiditis (SAT). However, its mechanism is unknown. TBII and TSAb measured using cultured FRTL-5 thyroid cells were evaluated in 18 patients with PT, 11 patients with SAT and a patient with SAT-like symptoms. In PT, we detected both TBII and TSAb activities in only 1 patient. This case had first come to our attention with subclinical hypothyroidism and had already had weakly positive TSAb activity (205.9%) 1 year before the present onset of PT. This patient had a transient thyrotoxicosis with a low uptake (24 h) of 123I (4.3%) and 821.0% TSAb activity, and subsequently developed a transient subclinical hypothyroidism. Even after 2 years, she still had positive TSAb activity (382.3%). In SAT, TBII and TSAb activities were not detected during the courses of any patients. A patient with transient thyrotoxicosis, who had a high uptake (30 min) of 99mTc (5.6%) and SAT-like symptoms (painful tenderness on right thyroid lobe and markedly accelerated erythrocyte sedimentation rate), showed positive activities of TBII (34.9%) and TSAb activity (1,366.9%). Histological findings by thyroid needle biopsy performed in the thyrotoxic phase showed coexistence of granulomatous inflammatory changes and hyperplasia with papillary folds of some residual follicular cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Two cases of persistent hypouricemia associated with diabetes mellitus.

Two patients with diabetes mellitus had persistent hypouricemia due to increased urate clearance; the degree of the apparent renal hypouricemia with uricosuria was quite mild. At the onset of diabetes, their serum urate levels were normal. Even after good diabetes control in both cases, hypouricemia continued. Based on the pharmacological evaluation in both patients, pyrazinamide administration could partially decrease urate clearance, however, suppression by pyrazinamide was less than in normal subjects, and probenecid increased urate clearance. These results suggest that the present cases had a renal abnormality affecting tubular presecretory reabsorption of urate, which might be due to diabetes mellitus.

Aged↗
PubMed1992

Plasma catecholamine responses to dynamic exercise in patients with coronary artery disease--the relationship between sympathetic activity and systolic blood pressure and exercise-induced ventricular arrhythmias.

In order to investigate the relationship between sympathetic activity and postexercise systolic blood pressure (SBP) and exercise-induced ventricular arrhythmias in patients with coronary artery disease (CAD), we studied 38 patients and 9 normal subjects who underwent treadmill testing. Peak pressure-rate product was similar in the 2 groups. The plasma concentrations of norepinephrine and epinephrine at rest and immediately after exercise were significantly higher in patients with CAD compared with normal subjects (norepinephrine at rest, p < 0.01; norepinephrine immediately after exercise, p < 0.05; epinephrine at rest, p < 0.05; epinephrine immediately after exercise, p < 0.05). The level of norepinephrine immediately after exercise was significantly higher in 15 patients with a postexercise SBP increase than in 23 patients without that SBP change (p < 0.05), whereas the level of epinephrine was similar in the 2 groups. The level of epinephrine immediately after exercise was significantly higher in 10 patients with exercise-induced premature ventricular contractions than in 28 patients without those arrhythmias (p < 0.05), whereas the level of norepinephrine was similar in the 2 groups. We conclude that a postexercise SBP increase is related to the augmentation of sympathoneural activity and that exercise-induced ventricular arrhythmias are related to the augmentation of sympathoadrenal activity.

Arrhythmias, Cardiac↗
PubMed1992

Determinants of subsequent late postoperative left ventricular function and reversal of ventricular dilatation after mitral valve replacement for chronic mitral regurgitation.

We studied 16 patients with chronic mitral regurgitation by echocardiography before, and at 3 weeks, at 6-8 months and at 1-9 years after mitral valve replacement (MVR) to investigate serial changes in left ventricular (LV) function and reversal of ventricular dilatation. All patients at an average of 2.6 years after, and 8 patients before MVR were also studied by echocardiography and, except for 3 patients by measuring plasma catecholamines from the right atrium during bicycle exercise. Before operation, all patients were divided into group A (n = 12) with end-systolic dimension (ESD) < 4 cm and systolic blood pressure (SBP)/ESD > 3, and group B (n = 4) with ESD > 4 cm and SBP/ESD < 3. Maximum reduction in end-diastolic dimension (EDD) occurred at 3 weeks in all patients after MVR (from 60.5 +/- 3.7 to 49.0 +/- 4.5 mm, p < 0.05). ESD was reduced significantly (p < 0.5) only in group A. LV function was normal in group A, but it was depressed in group B at early and late periods after MVR. The slopes of the relationship between the mean velocity of circumferential fiber shortening (Vcf) and plasma norepinephrine (NE) during exercise in all patients in group B decreased along with the depression in LV function. After operation, all patients in group A reached New York Heart Association (NYHA) functional class I, while patients in group B were in NYHA class II. It is concluded that the surgical outcome after MVR for chronic MR will be better if preoperative ESD < 4 cm and SBP/ESD > 3. The relationship between mean Vcf and plasma NE during exercise seemed to be a useful index to evaluate the inotropic reserve of the LV.

Echocardiography↗
PubMed1992

Cardiovascular and sympathetic nervous responses to mental stress in hyperthyroid patients.

We measured the cardiovascular and sympathetic nervous responses to mental stress in subjects with hyperthyroidism. Ten hyperthyroid subjects and 10 age- and sex-matched normal subjects performed mental arithmetic. At rest, the heart rate was higher in hyperthyroid subjects than in normal subjects, but systolic blood pressure, plasma norepinephrine, and epinephrine concentrations did not differ between the two groups. Systolic blood pressure and heart rate during stress, and the changes in blood pressure and in plasma epinephrine concentration from rest to stress, were higher in hyperthyroid subjects than in normal subjects. Therefore, cardiovascular and adrenal responses to mental stress were abnormally high in subjects with hyperthyroidism.

Adolescent↗
PubMed1992

Cardiovascular and sympathetic nervous response to dynamic exercise in patients with essential hypertension.

To investigate the relationship among systolic blood pressure (SBP) during exercise (EX), left ventricular hypertrophy (LVH) and plasma norepinephrine concentration (NE) in patients with essential hypertension (HT), 20 patients with HT and 20 age- and sex-matched normal subjects were studied using treadmill testing. According to the change in SBP from rest to EX (delta SBP), patients with HT were classified into two groups (group I, n = 12, delta SBP less than 72 mmHg: group II, n = 8, delta SBP greater than or equal to 72 mmHg). There were no significant differences between the two groups with regard to SBP at rest, NE at rest and NE on EX. However, SBP at peak EX, delta SBP and the incidence of LVH were greater in group II than in group I. We conclude that exaggerated SBP response to EX in patients with HT is related to LVH.

Adult↗
PubMed1992

Relation between serum uric acid and angiographically defined coronary artery disease in postmenopausal women.

Serum uric acid (UA) levels were studied in 40 postmenopausal women and 57 men, almost matched for age and body mass index (BMI) and undergoing coronary angiography. For women, the mean value of UA increased as the number of coronary arteries with > or = 50% stenosis increased. Its value was significantly higher (p < 0.05) in a three-vessel disease group than that of a group without stenosis. No significant changes were seen in men. However, the increase in UA for postmenopausal women was statistically (p < 0.05) correlated with serum triglyceride levels. Possibly, UA is not an independent coronary risk factor. However, elevated UA levels may suggest the prevalence of severe coronary artery stenosis for postmenopausal women.

Aged↗
PubMed1992

Serum levels of lipids and apolipoproteins in angiographically assessed coronary artery disease in Japanese patients.

Serum total cholesterol (T-CHO), triglyceride (TG), high density lipoprotein cholesterol (HDL-C) and apolipoproteins (apo A-I, A-II, B, C-II, C-III and E) values were determined in 143 Japanese subjects undergoing coronary angiography. Among the factors measured, T-CHO, TG, apo B and C-III levels were significantly higher in patients with coronary artery disease (CAD) than in those without CAD. The HDL-C/T-CHO ratio was also significantly lower in patients with CAD. Although no parameters show differences between the group without CAD and the group of single vessel disease, T-CHO and apo B were significantly higher in the groups with double and triple vessel disease, and TG and apo C-III were also higher in the group with triple vessel disease compared with the normal group. Furthermore, the HDL-C/T-CHO ratio was significantly lower in the double and triple vessel groups, and HDL-C was lower only in the triple vessel group. The results indicate that changes in these parameters suggest a high likelihood of multiple vessel disease, and that an increase in TG and apo C-III levels is also one of the important indicators for CAD even in Japanese patients.

Aged↗
PubMed1992

[Cardiac and plasma catecholamine response to dynamic exercise in hyperthyroidism].

To investigate cardiac and sympathoadrenal responses to dynamic exercise, heart rate, systolic blood pressure, serial plasma norepinephrine (NE) and epinephrine (E) concentrations during multistage treadmill exercise were measured in 24 hyperthyroid patients (mean age; 42 +/- 16) and 24 age-sex matched control subjects. Eleven patients were re-examined in the euthyroid state after antithyroid therapy. Exercise duration was shorter in patient with hyperthyroidism. Also, the heart rates and systolic blood pressures at rest and in the early stage of exercise were significantly higher in hyperthyroidism. NE at rest (normal vs hyperthyroid: 124 +/- 10 vs 80 +/- 7 pg/ml, p < 0.01) and NE at peak exercise (475 +/- 38 vs 310 +/- 38 pg/ml, p < 0.01) were lower in hyperthyroidism. E at rest (22 +/- 2 vs 29 +/- 4 pg/ml, n.s.) did not differ, however, E during the first stage of exercise (30 +/- 3 vs 69 +/- 12 pg/ml, p < 0.01) was higher in hyperthyroidism. Re-examination for the euthyroid state revealed the decreases in the heart rates and systolic blood pressures at rest and in the early stage of exercise, and the normalization of the NE and E response. Thus, patients with hyperthyroidism was in the hyperdynamic cardiac state at rest and during dynamic exercise, which was accounted for by decreased sympathetic nervous activity and increased adrenomedullary responses. These modifications of sympathoadrenal response seemed reversible when patients were controlled by antithyroid therapy.

Adolescent↗
PubMed1992

Cardiac neurosis: interactions between cardiac arrhythmias and symptoms using ambulatory ECG monitoring.

To investigate interactions between cardiac arrhythmias and subjective complaints and the background, ambulatory electrocardiographic (ECG) monitoring and a mental test [Cornell Medical Index (CMI)] were performed on 32 patients who complained of anxiety due to palpitation and/or tachycardic feelings without organic heart disease. The patients were classified into two groups according to the Holter ECG. In one group symptoms corresponded with cardiac arrhythmias (Group C; n = 15); and the other group lacked corresponding arrhythmias in spite of their significant symptoms (Group B; n = 17). From psychological view points, 65% of Group B and 40% of Group C patients showed grades III or IV of CMI tests, whereas only 5% showed grade III in normal volunteers (Group A; n = 20). Patients suffering symptoms without associated cardiac arrhythmias may have psychophysiologic backgrounds, at least in a part. It might be necessary in the treatment of these patients to pay attention to the factor of cardiac neurosis.

Adult↗
PubMed1991

Trimetazidine inhibits Na+,K(+)-ATPase activity, and overdrive hyperpolarization in guinea-pig ventricular muscles.

The effect of trimetazidine on Na+,K(+)-ATPase activity or the Na+,K+ pump was studied in guinea pig ventricular muscles with the use of biochemical and electrophysiological methods. The effect of trimetazidine on enzyme activity was compared with that in the liver, jejunum and kidney obtained from the same species. Na+,K(+)-ATPase activity in the heart and liver was significantly and concentration dependently decreased by trimetazidine (above 1.5 x 10(-5) M). Even the highest concentration (1.5 x 10(-4) M) of trimetazidine failed to decrease the Na+,K(+)-ATPase activity in the jejunum and kidney. The membrane potential was recorded in the ventricular muscle with a microelectrode. The hyperpolarization which followed 1-min overdrive stimulation (3.3 Hz) was decreased by trimetazidine (1.5 x 10(-4) M), but the depolarization during the stimulation was not affected by this drug. Ouabain, a potent Na+,K+ pump inhibitor, markedly decreased the overdrive hyperpolarization and increased the depolarization during the stimulation (10(-7), 5 x 10(-7), 10(-6) M). Therefore, the effect of trimetazidine and ouabain on the Na+,K+ pump-mediated alteration in the resting potential is different, suggesting that trimetazidine has additional direct membrane effects, e.g. a decrease in K+ conductance. In conclusion, trimetazidine inhibits Na+,K(+)-ATPase activity and thus the Na+,K+ pump in the ventricular muscles but with an inhibitory effect about 300 times less than that of ouabain. Trimetazidine inhibited the Na+,K(+)-ATPase in the liver as well, but not that in jejunum and kidney.

Animals↗
PubMed1991

Effects of aprindine on conduction velocity and Vmax in guinea-pig papillary muscles.

One of the effects of antiarrhythmic drugs is the reduction of conduction velocity. Cable theory predicts that there is a nonlinear relationship between conduction velocity and upstroke velocity (Vmax) of action potential. By using conventional microelectrode techniques, aprindine-induced reduction of Vmax of action potential and conduction velocity in guinea-pig papillary muscles were measured. Aprindine-produced, use-dependent, and concentration-dependent changes in conduction velocity and the decline of square of conduction velocity was well fit by a single exponential. Time constants for square of conduction velocity were comparable to simultaneously measured time constants for effects of Vmax. At a concentration of 1 to 10 microM aprindine, onset changes between Vmax and conduction velocity had a log-linear relationship in a predicted fashion. Whereas, in the recovery process from aprindine-induced depression, slow recovery time course of conduction velocity was observed. In conclusion, in the presence of aprindine, only onset block of conduction velocity can be analyzed quantitatively in the relationship to observation on Vmax in vitro. These results suggested that in the presence of aprindine, the recovery of internal conductance may be slower than that of Vmax.

Action Potentials↗
PubMed1991

Effect of urapidil on the action potentials in the guinea-pig ventricular myocardium.

The electrophysiological effects of urapidil, a new alpha 1-adrenoceptor antagonist, were assessed in the reserpinized guinea-pig ventricular myocardium. Urapidil suppressed the maximal rate of rise (Vmax) of steady-state action potentials elicited by the fast responses at high concentrations independently of blockade of myocardial alpha-adrenoceptors, but not the Vmax of Ca(2+)-dependent slow action potentials of partially depolarized muscles in concentrations tested (up to 1.1 mM). Urapidil at high concentrations prolonged the action potential durations of the fast and slow responses in a manner similar to the quinidine-like antiarrhythmic drugs. These results suggest that the inhibitory effect of urapidil on the slow inward Ca2+ current and the Na+ current is in practice negligible.

Action Potentials↗
PubMed1991

Aprindine blocks the sodium current in guinea-pig ventricular myocytes.

Aprindine is a class Ib antiarrhythmic agent. We studied effects of aprindine (3 mumol/l) on the Na+ current using whole cell voltage clamp (tip resistance = 0.5 M omega, [Na]i ando = 10 mmol/l at 18 degrees C). Aprindine revealed tonic block (Kdrest = 37.7 mumol/l, Kdi = 0.74 mumol/l; n = 4). Aprindine, shifted inactivation curve to hyperpolarizing direction by 11.4 +/- 3.5 mV (n = 4) without changes in slope factor. In the presence of 3 mumol/l aprindine, aprindine showed phasic block, i.e., duration-dependent block at 2 Hz (64% +/- 3% at 1.5 ms, 82% +/- 6% at 20 ms, 93% +/- 7% at 200 ms; n = 4). Short single prepulse also produced aprindine-induced phasic block (12% at 1.5 ms, 22% at 100 ms; n = 2). After removal of fast inactivation of Na+ current by 3 mmol/l tosylchloramide sodium, aprindine revealed phasic block, independent of holding potential. The recovery time constant from aprindine-induced phasic block was 4.8 s at holding potential = -100 mV and 5.0 s at holding potential = -140 mV. This use-dependent block of aprindine had pH dependency. Under acidic condition (pH 6.0), 3 mumol/l aprindine showed smaller use-dependent block (14% +/- 7% at 2 Hz; n = 4) comparing with either at pH 7.4 (68% +/- 13%; n = 4) or at pH 8.0 (90% +/- 12%; n = 4). The results suggest that aprindine could bind to the receptor via activation process through channel pore, resulting in decrease of Na+ current, and egress from the receptor through the lipid bilayer. These effects might be attenuated under acidic condition due to changes in intracellular ratio of charged to neutralized form of drug molecule.

Action Potentials↗