Biomedical subjects

H Mashiba

Publications and source records attributed to H Mashiba.

At least 37 records · Page 2Linked to original sources

PubMed1997

[Prognostic survey of elderly patients with hypertension in the Chugoku and Shikoku districts--mortality and morbidity of cardiovascular complications. Study Group for Elderly Hypertensives in Chugoku and Shikoku Districts].

In order to examine the current status of antihypertensive drug therapy for elderly hypertensive patients, and the effect of clinical characteristics and drugs on their prognosis, 1669 hypertensive patients in the Chugoku and Shikoku districts, aged between 65 and 84 years, were enrolled and followed for 3 years. Of the 1669 patients enrolled, 1459 were selected for evaluation and 1127 patients were followed. Group A comprised 955 patients who had not suffered from any accident, group B comprised 139 patients who had suffered from a cerebral, cardiac, renal or other non-fatal accident, and group C comprised 33 patients who died. The mortality rate was 10.7/1000 patient.years and the morbidity rate was 55.6/1000 patient.years. The number of patients who received monotherapy was 736 (calcium channel blockers: #436, beta blockers: #100, angiotensin converting enzyme inhibitors: #80, diuretics: #64, alpha blockers: #16; others: #13). In group C, there were more male, and the patients were older and showed a higher level of serum creatinine concentration at enrollment compared with other groups. The use of diuretics and beta blockers tended to be low in this group. Among the three groups, however, there was no difference in blood pressure, heart rate or the use of each drug at enrollment. In summary, it is suggested that the different antihypertensive drug therapies die not influence the prognosis of elderly hypertensive patients.

Aged↗

PubMed1997

Effect of Helicobacter pylori eradication on subsequent development of cancer after endoscopic resection of early gastric cancer.

Although epidemiological studies strongly suggest an association between gastric cancer and Helicobacter pylori infection, there has been no clinical report indicating that cure of the infection prevents cancer. We conducted a nonrandomized H. pylori eradication trial in patients whose gastric cancer was removed by endoscopic resection (ER). We investigated the effect of treatment on the histopathology of the gastric mucosa, as well as on the incidence of metachronous gastric cancer during the long-term clinical and endoscopic follow-up. One hundred and thirty-two patients with early gastric cancer underwent ER and had H. pylori infection. Sixty-five (group A) were treated with omeprazole and antibiotics to eradicate the infection, and 67 (group B) were not. All patients were followed for 2 years post ER. After eradication treatment in group A, the disappearance of neutrophil infiltration in the antrum and body of the stomach was observed as was a decrease of the severity of intestinal metaplasia. Endoscopy after ER detected no new gastric cancers in these patients. After 3 years of follow-up, 6 (9%) of the 67 patients in group B had a new early-stage, intestinal-type gastric cancer endoscopically diagnosed. The above results suggest that H. pylori eradication may improve neutrophil infiltration and intestinal metaplasia in the gastric mucosa and inhibit the development of new carcinomas. This finding should be confirmed in a randomized, controlled trial.

Adult↗

PubMed1996

Ammonia response to exercise in patients with congestive heart failure.

OBJECTIVE: To assess energy depletion in skeletal muscle in patients with congestive heart failure by measuring blood purine metabolites during exercise and, at the same time, determine the implications of the ammonia response to exercise in these patients. SETTING: Tottori University Hospital, Yonago, Japan. PATIENTS: 49 heart failure patients (New York Heart Association (NYHA) grades I-III) and 16 normal subjects. MAIN OUTCOME MEASURES: Blood lactate, ammonia, and hypoxanthine levels were measured during exercise with expired gas analysis. RESULTS: In normal exercising subjects as well as in each heart failure subgroup, the ammonia threshold was significantly higher than both the lactate threshold [control: 21.8 (SD 5.3) v 17.4 (3.3) ml/kg/min; NYHA class I: 18.9 (3.8) v 15.5 (2.6); class II: 14.8 (2.5) v 12.7 (2.4); class III: 13.5 (2.6) v 11.8 (2.5)] and the ventilatory threshold (P < 0.01). The difference between the ammonia and lactate thresholds was noted in all normal subjects and in all heart failure patients. The ammonia threshold, however, was significantly lower in heart failure patients than in normal subjects and it decreased with increasing NYHA class (P < 0.01). Maximum ammonia levels were lower in the heart failure group and decreased further with higher NYHA classifications [control: 198 (52) mg/dl; NYHA class I: 170 (74); class II: 134 (58); class III: 72 (15); P < 0.01]. There were significant correlations between maximum ammonia values and maximum lactate, oxygen consumption, and hypoxanthine levels (r = 0.74, 0.48, and 0.87, respectively; P < 0.001). CONCLUSIONS: The ammonia threshold may reflect the onset of ATP depletion in exercising skeletal muscles, as opposed to the onset of anaerobic respiration. It seems therefore that energy depletion in skeletal muscles during exercise occurs after attaining the anaerobic threshold. Both aerobic and anaerobic capacities of skeletal muscle are reduced in patients with congestive heart failure.

Adenosine Triphosphate↗

PubMed1996

Exercise-induced U-wave changes in patients with coronary artery disease--correlation with tomographic thallium-201 myocardial imaging.

We studied the relation between exercise-induced U-wave changes and the site of a reversible defect in tomographic 201Tl myocardial imaging. Coronary artery disease and control groups consisted of 116 and 42 patients, respectively. In the anteroapical-ischemia group (n = 37), the sensitivity of U-wave inversion in the anterior precordial leads for ischemia was 62% (23/37) and that of prominent U-waves without an increase in the height of the T-wave in the inferior limb leads was 57% (21/37). In this group, 18 patients (49%) met both criteria (18 [78%] of 23 patients with the former; 18 [86%] of 21 patients with the latter). In the posterior-ischemia group (n = 59), the sensitivity of prominent U-waves with a decrease in the height of the T-wave in the anterior precordial leads for ischemia was 63% (37/59) and that of U-wave inversion in the inferior limb leads was 20% (12/59). In this group, 12 patients (20%) met both criteria (12 [32%] of 37 patients with the former; all 12 patients with the latter). The specificity of U-wave criteria was 100%. In the anteroapical and posterior ischemia group (n = 20), the sensitivity of U-wave criteria for anteroapical and posterior ischemia was 85% (17/20) and 40% (8/20), respectively. In conclusion, U-wave criteria are not only specific but also sensitive for myocardial ischemia determined by 201Tl imaging.

Aged↗

PubMed1996

Decreased heart rate variability in patients with diabetes mellitus and ischemic heart disease.

We investigated the characteristics of decreased heart rate variability (HRV) in diabetic patients with ischemic heart disease (IHD). Twenty-one healthy control subjects, 17 diabetic patients without IHD, and 33 diabetic patients with IHD were studied. The diabetic patients with IHD were subdivided into 2 groups according to the severity of their IHD: severe or mild. HRV was evaluated in all subjects using the spectral variables of the all-frequency, low-frequency, high-frequency (AF, LF, HF) components and the LF/HF ratio were determined from Holter recordings. The AF and LF components in patients with diabetes only or diabetes and severe IHD were significantly lower than in control group, but the HF component was significantly lower only in the group of patients with diabetes and severe IHD. The LF/HF ratio did not differ significantly among the 4 groups, but was the lowest in diabetic patients without IHD. Patients with diabetes and mild IHD showed a slight decrease in HRV, but this was not significant. With regard to the circadian rhythm of HRV, the AF and LF components in patients with diabetes-only or diabetes and severe IHD were significantly decreased and showed the same pattern throughout the day. However, the HF component was decreased during more time zones in patients with diabetes and severe IHD, whereas the LF/HF ratio was lower during more time zones in the diabetes-only group. All spectral variables showed a tendency to be inversely related to the duration of diabetes in all diabetic patients. In particular, the LF/HF ratio showed a significant negative correlation. The HRV of diabetic patients was characterized by a decreased LF/HF ratio. It was concluded that, although HRV in diabetic patients with severe IHD was reduced mainly as a result of diabetic neuropathy, this was also partly due to a decline in parasympathetic tone as a result of myocardial injury.

Aged↗

PubMed1996

Adult respiratory distress syndrome induced by a Chinese medicine, Kamisyoyo-san.

We report the first case of Kamisyoyo-san-induced adult respiratory distress syndrome (ARDS). A 59-year-old female was given Kamisyoyo-san for treatment of seborrheic dermatitis. She then presented with a respiratory illness having clinical, radiologic and functional characteristics of ARDS. Bronchoalveolar lavage fluid showed an increased number of lymphocytes, neutrophils and eosinophils. The lymphocyte stimulation test with Kamisyoyo-san was positive.

Bupleurum↗

PubMed1996

Cardiac angiosarcoma.

Angiosarcoma is one of the most common cardiac tumors, but early detection of this tumor is often difficult, as exemplified by our patient, a 55-year-old woman whose cardiac tumor was first detected by echocardiography. Surgical removal of the tumor was impossible due to its extensive pericardial invasion. Pathological diagnosis was not complete before autopsy because of the wide occupied necrotized area of the tumor. There is no diagnostic imaging technique available to detect such a necrotized area. An imaging technique more powerful than echocardiography and able to diagnose angiosarcoma earlier is needed.

Biopsy↗

PubMed1996

[Clinical incidence of primary cardiac tumors].

Recently, clinical diagnostic methods for heart disease, especially echocardiography, have remarkably progressed and the incidence of cardiac tumors increased. This study investigated the characteristics of tumors in 115 patients with primary cardiac tumor, diagnosed histologically in 1993-1994, in collaboration with 126 university hospitals in Japan. Histological diagnosis, location, initial clinical manifestations and prognosis of cardiac tumors are reported. Of the 115 patients, 98 (85%) had primary benign tumor. Myxoma was the most common histological group (91 cases). Primary malignant cardiac tumors occurred in 17 patients (15%) of which rhabdomyosarcoma was the most frequent (5 cases). Sixty percent of patients with myxoma were female, a similar ratio to the proportion of female patients with other primary cardiac tumors. Most patients with myxoma had the tumor in the left side of the heart [76 cases (84%) in left side, 12 (13%) in right side, 3 (3%) in both sides]. In contrast, the primary malignant cardiac tumors occurred more in the right side of the heart rather than in the left side (eight in right side, six in left side). Embolization was the characteristic initial clinical manifestation for myxoma. There were no patients with initial manifestation of embolization in the other histological groups. Reflecting the recent progress and spread of clinical diagnostic methods, 17% of all patients were discovered asymptomatically. All patients with myxoma who were asymptomatic underwent operation, and there were no surgical deaths. In contrast, only one patient with primary malignant cardiac tumor could survive longer than a year. In conclusion, the progress and the spread of cardiovascular imaging has contributed to the early diagnosis of primary cardiac tumors. These data demonstrate new clinical and pathological characteristics of primary cardiac tumors seen in recent cardiologic practice in Japan.

Adolescent↗

PubMed1995

Plasma concentrations and coronary vasodilation after sublingual and intracoronary administration of isosorbide dinitrate.

To investigate the relationship between plasma levels and coronary vasodilation after administration of isosorbide dinitrate (ISDN), the plasma concentration and diameters of six segments of the left coronary artery were measured before and after sublingual (SL) ISDN (5 mg) and left intracoronary (IC) administration of ISDN (3 mg) in 12 patients. After SL-ISDN, the systolic aortic pressure decreased with no significant concomitant changes in heart rate or diastolic aortic pressure. After IC-ISDN, all hemodynamic parameters showed significant changes, and these were greater after IC-ISDN than those after SL-ISDN. The individual mean vasodilation of six segments induced by SL- and IC-ISDN, were 23 +/- 9 and 35 +/- 11% (p < 0.01), respectively. Before SL-ISDN, ISDN was not detected in plasma. After SL- and IC-ISDN, however, the plasma values of the ISDN were 36.1 +/- 53.3 and 101.5 +/- 90.0 ng/ml (p < 0.01), respectively. Thus, both coronary vasodilative responses and plasma ISDN levels after IC-ISDN were significantly greater than those after SL-ISDN. However, neither the individual mean coronary vasodilation nor the hemodynamic changes correlated significantly with plasma ISDN levels. Consequently, with administration of the same dose, the coronary vasodilative response to ISDN did not correlate with plasma levels. Furthermore, IC-ISDN dilutes coronary arteries more effectively than SL-ISDN.

Administration, Sublingual↗

PubMed1995

Quinidine enhances intracellular Ca2+ accumulation during rapid stimulation.

1. The quinidine-induced modification of intracellular Ca2+ concentration ([Ca2+]i) was studied in guinea-pig myocardium using fura-2. Quinidine reduced the systolic fluorescence signal level for [Ca2+]i and enhanced the end-diastolic signal level during a stimulation train. 2. The diastolic decay of [Ca2+]i fitted 2 exponential curves. Quinidine distorted the stimulation frequency-dependent acceleration of rapid [Ca2+]i decay, and prolonged the mean time constant of rapid decay after 2 Hz stimulation, from 154.4 to 205.3 msec (20 microM), and to 259.7 msec (60 microM quinidine). The time constant of slow recovery from [Ca2+]i accumulation after the stimulation train was not affected by stimulation frequency, or by quinidine, or caffeine. 3. These results suggest that quinidine modulates [Ca2+]i via a balance between the slowing of rapid [Ca2+]i decay and the reduction of the systolic [Ca2+]i. This effect may contribute to the anti-arrhythmic and pro-arrhythmic effects exerted by quinidine in some conditions.

Animals↗

PubMed1995

A patient with an autonomously functioning thyroid nodule with papillary adenocarcinoma associated with Graves' hyperthyroidism.

A 69-year-old man had concomitant findings of an autonomously functioning thyroid papillary adenocarcinoma and Graves' hyperthyroidism. The patient presented with hyperthyroidism and a right lobe thyroid nodule that was shown to be hyperfunctional on I-123 imaging. The TI-201 imaging showed uptake confined almost entirely to the right lobe nodule. Papillary adenocarcinoma in the nodule and diffuse hyperplasia surrounding the nodule along with a slightly enlarged left lobe were found at surgery.

Adenocarcinoma, Papillary↗

PubMed1995

Cardiovascular effects of intracerebroventricularly administered growth hormone-releasing factor in spontaneously hypertensive rat.

1. We investigated the cardiovascular effects of intracerebroventricularly administered (ICV) growth hormone-releasing factor (GRF) in both spontaneously hypertensive rats (SHR) and Wistar rats (WR) with reference to the involvement of adrenergic mechanisms and plasma AVP concentration. 2. The ICV GRF induced biphasic changes of mean arterial pressure (MAP) in SHR. In the first phase, maximum pressor response was observed 2-3 min after injection. In the second phase, maximum depressor response was observed 12-13 min after injection, and lasted up to 21-22 min. In WR, there were no significant changes in MAP. 3. ICV phentolamine attenuated the GRF-induced pressor response, but did not affect the depressor response. ICV bunazosine had no effect in both responses. ICV yohimbine attenuated the GRF-induced pressor response, but did not affect the depressor response. 4. In SHR, plasma AVP concentration was not affected by ICV GRF. 5. These data suggest that central GRF plays an important role in the maintenance of hypertension in SHR, since ICV GRF caused a significant depressor effect in SHR but not in WR. ICV GRF induced biphasic changes of MAP in SHR. The pressor response was mediated through central alpha2-adrenoceptors. The depressor response was not mediated through central alpha-adrenoceptors. The depressor effect of ICV GRF was not mediated by the changes of plasma AVP concentration.

Animals↗

PubMed1995

Mechanism of inhibition of the sodium current by bepridil in guinea-pig isolated ventricular cells.

1. Effects of bepridil, a sodium-, calcium-, and potassium-antagonistic agent, on the Na+ current were studied by the whole cell voltage clamp technique (tip resistance = 0.5 MOhm, [Na]i and [Na]o 10 mmol l-1 at 20 degrees C). 2. Bepridil produced tonic block (Kdrest = 295.44 mumol l-1, Kdi = 1.41 mumol l-1; n = 4). 3. Bepridil (100 mumol l-1) shifted the inactivation curve in the hyperpolarization direction by 13.4 +/- 2.7 mV (n = 4) without change in the slope factor. 4. In the presence of 50 mumol l-1 bepridil, bepridil showed use-dependent block at 2 Hz, whereas changes in pulse duration did not significantly effect this use-dependent block (81% +/- 2% at 10 ms, 84% +/- 3% at 30 ms, 86% +/- 3% at 100 ms; n = 4). 5. After removal of fast inactivation of the Na+ current by 3 mmol l-1 tosylchloramide sodium, bepridil (50 mumol l-1) still showed use-dependent block which was independent of the holding potential. 6. The recovery time constant from the bepridil-induced use-dependent block was 0.48 s at holding potential of -100 mV and 0.51 s at holding potential of -140 mV. 7. These results indicate that bepridil could bind to the receptor in the sodium channel through the hydrophobic and the hydrophilic pathway and leave the receptor through the hydrophobic pathway in the lipid bilayer. The binding and dissociation kinetics of this drug were shown to be fast, and the accumulation of the drug in the sodium channel appeared to be small. Bepridil is presumed to be safe in terms of adverse effects that result from drug-accumulation in the sodium channel.

Animals↗

PubMed1995

Exercise-induced ST-segment elevation--role of left ventricular wall motion abnormalities and coronary artery narrowing.

We studied the causes of exercise-induced ST-segment elevation. Group I consisted of 15 patients with anterior myocardial infarction in the absence of a coronary artery luminal narrowing of 75% or more. Group II consisted of 36 patients with predominantly exertional angina and a luminal narrowing of 90% or more in the left anterior descending coronary artery in the absence of previous myocardial infarction. In group I, exercise-induced ST-segment elevation occurred frequently during treadmill exercise (15/15, 100%). None of the patients showed 201Tl redistribution. The standard deviation of the phase in radionuclide ventriculography increased during bicycle exercise. Of group II patients, only those with 99% narrowing and poor collaterals showed exercise-induced ST-segment elevation (13/14, 93%), whereas none of those with complete occlusion or 99% narrowing and good collaterals, or 90% narrowing showed ST-segment elevation. In group II, patients with exercise-induced ST-segment elevation showed lower 201Tl uptake during exercise and washout in the territory of the diseased vessel than those without exercise-induced ST-segment elevation. In conclusion, wall motion abnormalities may cause exercise-induced ST-segment elevation independently of myocardial ischemia. In patients with predominantly exertional angina, exercise-induced ST-segment elevation may be a marker for 99% narrowing with poor collaterals and severe myocardial ischemia.

Adult↗

PubMed1995

Neurohumoral factor responses to mental (arithmetic) stress and dynamic exercise in normal subjects.

We examined the responses of plasma catecholamine and plasma renin activity (PRA) during mental (arithmetic) stress and dynamic exercise in 15 normal subjects. Compared to rest values, there was a significant increase in the plasma epinephrine concentration (E), but not in the plasma norepinephrine concentration (NE) or PRA during mental arithmetic. During dynamic exercise, there were significant increases in both NE and E and in PRA. The ratio of E to NE was significantly higher during mental arithmetic than during dynamic exercise. NE was significantly correlated with PRA at rest, during mental arithmetic and dynamic exercise. No significant correlations were observed between E and PRA. Dynamic exercise primarily induces a sympathetic nervous response, and mental (arithmetic) stress mainly induces an adrenal response. The renin-angiotensin-aldosterone system response may in part be regulated by sympathetic nervous activity during both mental (arithmetic) stress and dynamic exercise.

Adult↗

PubMed1995

Development of hypercalcemic crisis in a Graves' hyperthyroid patient associated with central diabetes insipidus.

A 26-year-old man with Graves' hyperthyroidism associated with central diabetes insipidus (DI), initially showed hypercalcemic crisis. Initially, very low serum levels of intact parathyroid hormone (PTH) and 1,25-dihydroxy vitamin D3 and a moderate rise of serum C-terminal PTH related protein (C-PTHrP) were observed which strongly suggested a humoral hypercalcemia of malignancy due to PTHrP. However, the serum C-PTHrP level later became normal. Mild hyperprolactinemia, no responses of growth hormone (GH) to insulin-induced hypoglycemia despite a normal growth hormone releasing hormone (GRH) test and mild thickening of the pituitary stalk on magnetic resonance imaging were observed. Thus, an autoimmune nature of his central DI is considered; it is noteworthy that the serum C-PTHrP level may be elevated by renal failure in patients with hypercalcemia due to causes other than PTHrP.

Acute Disease↗

PubMed1995

Effects of a new calcium channel blocker, MPC-1304, on blood pressure, serum lipoproteins and serum carbohydrate metabolism in patients with essential hypertension.

The effects of MPC-1304, a new calcium channel blocker, on blood pressure, serum lipoproteins, and carbohydrate metabolism were compared with those of atenolol in a group of patients with mild to moderate essential hypertension. Systolic and diastolic pressures were significantly decreased by both MPC-1304 and atenolol administration. Serum levels of apolipoproteins A-I and A-II were significantly increased after 8-12 weeks of MPC-1304 treatment, but were unchanged during a similar period of atenolol treatment. Neither drug induced any significant change in other lipoprotein parameters, fasting blood sugar, immunoreactive insulin, C-peptide or HbA1c. No serious side-effects or abnormal laboratory values were observed during the course of administration of either drug. These findings indicated that MPC-1304 is as efficacious as an antihypertensive drug and is without adverse effect on lipoprotein or carbohydrate metabolism.

Adult↗

PubMed1995

A new class III antiarrhythmic drug, MS-551, blocks the inward rectifier potassium channel in isolated guinea pig ventricular myocytes.

We have studied the effects of MS-551 on the inward rectifier potassium channel (IK1) in isolated guinea-pig ventricular myocytes by use of whole-cell and single-channel recording techniques. MS-551 (5 microM) blocked the IK1 current. The percent blockade of the peak and steady-state IK1 current by MS-551 was constant at each test potential. In contrast 50 microM MS-551 failed to block either the sodium or the calcium current. Under cell-attached patch conditions, MS-551 reduced the open probability of IK1 channel activity by prolonging the interburst interval without changing either the unitary amplitude or the equilibrium potential. The blockade of IK1 was concentration-dependent. MS-551 did not change either the mean open time or mean closed time within a burst. Extracellular acidification (pH 6.4) strongly attenuated the effect of MS-551 on the open probability of IK1 channel activity when compared with its effect at pH 7.4. In summary, our results demonstrated that MS-551 blocked the IK1 channel. The neutral form of this drug molecules may penetrate the cardiac cell membrane via a hydrophobic pathway to block the steady-state IK1 current by reduction of open probability.

Animals↗