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Biomedical subjects

H Mashiba

Publications and source records attributed to H Mashiba.

At least 127 records · Page 7Linked to original sources
PubMed1991

Clinical study on coupling interval of ventricular premature contraction in patients with organic heart disease.

The characteristics of the coupling interval (CI) of ventricular premature contraction (VPC) were studied in 100 patients with frequent VPCs using 24 h ambulatory ECG recording. All R-R intervals were registered on computer to determine the mean value of CIs (Mean CI) and the standard deviation of CIs (SD-CI). We compared the Mean CI and the SD-CI between idiopathic VPCs and VPCs with organic heart disease (OHD). In addition, we evaluated the efficacy of disopyramide (DP) and mexiletine (MX) and we examined the relationship between the efficacy of these drugs and the characteristics of CI. The Mean CI of VPCs with OHD was longer than that of idiopathic VPCs (530 vs. 494 msec, p less than 0.05). The SD-CI of VPCs with OHD was larger than that of idiopathic VPCs (54.1 vs. 39.3 msec, p less than 0.01). In all treated cases, the drug efficacy was not different between DP (11/18, 61%) and MX (9/19, 47%). However when we isolated cases of OHD, we found a tendency that DP (9/12, 75%) was more effective than MX (7/16, 44%). In cases where DP was administered, the Mean CI of VPCs was not different between effective and ineffective cases, while in cases where MX was administered, the Mean CI of ineffective cases had a tendency to be longer than that of effective cases (552 vs. 506 msec, p less than 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Complexes, Premature↗
PubMed1991

Significance of coronary artery tone assessed by coronary responses to ergonovine and nitrate.

The coronary artery response to ergonovine (EM) and nitrate of the proximal, middle and distal segments of the three major coronary artery branches and the main trunk was quantified in 67 patients without coronary spasm and in 69 patients with coronary spasm without significant organic stenosis. The changes in control diameter and diameter after EM administration compared to diameter after nitrate were used as the index of coronary artery tone. EM increased coronary artery tone regardless of the occurrence of coronary spasm (p less than 0.01). In all segments, basal coronary artery tone was greater in patients with spasm than in patients without spasm (p less than 0.01) in a way similar to the coronary responses to EM (p less than 0.01). In patients with spasm, both coronary artery tone after EM and basal coronary tone were greater in the spastic segments than in the nonspastic segments (p less than 0.01), which were greater than those in patients without spasm (p less than 0.01). Our data suggest that patients with spasm may have increased basal tone, and that coronary artery spasm may be based on increased coronary tone. Clinically, evaluation of the basal tone and response to EM in the entire coronary artery tree may be useful for predicting the presence of coronary artery spasm.

Cardiac Catheterization↗
PubMed1991

[Rupture of hepatocellular carcinoma with multiple pulmonary metastasis successfully treated by transcatheter arterial embolization (TAE) of tumor: a case report].

A 66-year-old woman was hospitalized in a state of shock with rupture of hepatocellular carcinoma and multiple pulmonary metastasis. Her bleeding was successfully controlled by emergency transcatheter arterial embolization with Lipiodol (Lp-TAE). Treatments with UFT, OK-432 and two additional Lp-TAE caused the disappearance of pulmonary metastasis with AFP levels decreased and natural killer cell activity increased. The patient died one and a half years after the emergency Lp-TAE. The disappearance of pulmonary metastatic lesions seemed to be caused by improvement of the patient's immunity, which related to the regression of primary tumor after Lp-TAE. It was suggested that Lp-TAE is worth undertaking even in rupture of hepatocellular carcinoma with remote metastatic lesions.

Aged↗
PubMed1991

An unexpected rise in plasma aldosterone to furosemide-upright test in primary aldosteronism due to aldosterone producing adenoma.

This paper documents an unexpected rise in plasma aldosterone concentration (PAC) to the furosemide-upright test despite a decrease in adrenocorticotropin (ACTH) by dexamethasone, and an unresponsiveness in plasma renin activity to this stimulus in a patient with aldosterone producing adenoma. Furthermore, this patient showed an appropriate response in PAC to a rapid ACTH test, and an insensitivity in PAC to angiotensin-II (Ang-II) infusion. Other factor(s) besides ACTH or Ang-II may play a role in the plasma aldosterone response to ambulation after intravenous furosemide administration in patients with primary aldosteronism.

Adenoma↗
PubMed1991

Bunazosin, an alpha-adrenoceptor antagonist, blocks calcium current in guinea-pig ventricular myocytes.

1. Effect of bunazosin, an alpha 1-adrenoceptor antagonist, upon the slow inward Ca2+ current (ICa) was studied in single ventricular myocytes of the guinea-pig using a whole-cell patch-clamp technique. 2. Bunazosin (10-100 microM) decreased ICa in a concentration-dependent manner with an IC50 of 60 microM during depolarization to + 10 mV from the holding potential of -40 mV. 3. As for the inactivation process of ICa, the steady-state inactivation (f infinity) curve was shifted toward more negative potentials from -12 mV to -17 mV and -21 mV at f infinity = 0.5, by 30 microM and 70 microM bunazosin. 4. Inhibition of ICa by the compound (10 microM) was also dependent on stimulation frequency, with greater block induced at 2 Hz (50%) than at 0.33 Hz (13%). 5. It is concluded that bunazosin possesses a direct Ca2+ channel-blocking (class 4) action in a rate-dependent fashion.

Adrenergic alpha-Antagonists↗
PubMed1991

[Evaluation of cardiac complications in patients with Duchenne muscular dystrophy using echocardiography--a comparison between patients with and without mechanical ventilation].

Two-dimensional echocardiography and Doppler echocardiography were performed in 19 patients with Duchenne muscular dystrophy for evaluating right ventricular overload and left ventricular function. Five of 19 patients were treated with mechanical ventilation. We defined right ventricular overload as right ventricular enlargement and the presence of paradoxical ventricular septal motion. The right ventricular dimensions in patients with mechanical ventilation were significantly larger than in patients without mechanical ventilation (p less than 0.01). All the patients with and without mechanical ventilation showed no significant right ventricular enlargement and none of them showed paradoxical ventricular septal motion. As for left ventricular function, there were no significant differences in the incidence of regional or diffuse wall motion abnormalities between two groups. However, the left ventricular fractional shortening was significantly lower in patients with mechanical ventilation than in patients without it (p less than 0.05), and the incidence of mitral regurgitation was significantly higher in the former than in the latter (p less than 0.01). Our findings suggest that right ventricular function is preserved even in patients with respiratory failure by appropriate respiratory treatment. Therefore, we should give attention to the progression of left ventricular dysfunction in long term prognosis.

Adolescent↗
PubMed1991

Stimulating effect of thyroid hormone on insulin-like growth factor I release and synthesis by perfused rat liver.

The direct effect of thyroid hormone on insulin-like growth factor I (IGF-I) release and synthesis was investigated in perfused rat liver. Physiological doses (from 50 to 1000 ng/dl) of 3,5,3'-triiodothyronine administration in the perfusing medium increased IGF-I release and concentration in the perfused liver in a dose dependent manner. While physiological doses (from 2 to 10 micrograms/dl) of thyroxine did not affect the release and synthesis of IGF-I in the perfused liver. These results suggest that 3,5,3'-triiodothyronine, but not thyroxine, directly enhances the release and synthesis of IGF-I in a dose dependent manner in the rat liver.

Animals↗
PubMed1991

Clinical significance of hypouricemia in hospitalized patients.

Serum uric acid was measured in 586 normal subjects and 1,220 hospitalized patients. Hypouricemia was noted in 0.34% of the normal subjects and 2.54% of the hospitalized patients. Among hospitalized patients with hypouricemia, 22 were on medication, including allopurinol, anticancer drugs, antibiotics and glucocorticoids. Twenty-one patients had liver disorders and 11 of them had received transfusions. Neoplastic diseases were noted in 14 patients. Thus, hypouricemia was found to be relatively common in hospitalized patients, and seems to be caused mainly by medication, neoplastic diseases, liver disorders and transfusions.

Adolescent↗
PubMed1990

Immunotargeting approach utilizing production of oxygen free radicals.

Tumor-specific inhibition of cell proliferation through production of oxygen free radicals was studied by using immunoconjugates. Diethyldithiocarbamate (DDC), an inhibitor of superoxide dismutase activity (SOD), was conjugated with anti-Meth A tumor cell antibodies. The addition of these conjugates in combination with ascorbic acid (AsA) induced marked inhibition of Meth A tumor cell proliferation. Pretreatment of the target cells with these conjugates followed by the addition of AsA was also effective in inhibiting cell proliferation. However, the pretreatment of the target cells with unconjugated anti-Meth A tumor cell antibodies in combination with AsA eliminated the DDC conjugate-mediated antiproliferative effect. These results suggest that the combined use of DDC-anti Meth A tumor cell antibody conjugates with AsA may be a beneficial approach to cancer therapy.

Animals↗
PubMed1990

Bunazosin induces use-dependent slowing of conduction in guinea-pig ventricular myocardium.

The use-dependent effects of bunazosin on the maximal rate of rise (Vmax) of the action potential and conduction velocity were studied in isolated papillary muscles of guinea-pig. Standard microelectrode techniques were used to monitor the conduction and action potential of the muscles. In the presence of 30 microM bunazosin, the time constants for the start of the use-dependent inhibition of Vmax during a 0.2, 1, 2 and 3 Hz stimulation were (means +/- S.E.M. in s) 30.9 +/- 8.0, 15.0 +/- 1.6, 7.4 +/- 0.9 and 3.9 +/- 0.7 (n = 4) and those for conduction velocity were 17.3 +/- 2.3, 17.3 +/- 5.2, 6.5 +/- 0.9 and 3.4 +/- 0.2, respectively. These results showed that in the cardiac ventricular muscle of the guinea-pigs, bunazosin produces use-dependent changes in conduction velocity with onset kinetics comparable to those measured simultaneously using Vmax. The characteristics of the use-dependent inhibition of conduction velocity induced by bunazosin are similar to those found with slow kinetic drugs such as disopyramide rather than with fast ones.

Action Potentials↗
PubMed1990

Acute effect of thyroid hormone on insulin secretion in rats.

To elucidate the mechanism of thyroid hormone-induced hyperinsulinemia, the acute and direct effect of thyroid hormone administration on insulin secretion was investigated in rats in vivo and in vitro. In the perfused rat pancreas, the addition of thyroxine (10 micrograms/dL) or 3,5,3'-triiodothyronine (150 ng/dL) to the perfusing medium did not affect insulin secretion. The administration of thyroxine (40 micrograms/kg, s.c.) in vivo increased the plasma insulin level from 11 +/- 2 microUnits/mL (mean +/- SD) to 30 +/- 7 microUnits/mL, while blood glucose and plasma glucagon were unchanged. This phenomenon was inhibited completely by the preadministration of oxprenolol hydrochloride (2 mg/kg, s.c.), and inhibited partly by the preadministration of metoprolol tartrate (35 mg/kg, s.c.). These results suggest that thyroid hormone induces hyperinsulinemia via beta-adrenergic stimulation in the rat.

Animals↗
PubMed1990

Blocking effect of 1389-S on the sodium current in isolated guinea-pig ventricular myocytes.

Under whole cell patch conditions, 1389-S blocked the INa in guinea-pig ventricular myocytes under steady state conditions (Kdrest = 30 microM, Kdi = 2.4 microM) with a shift of the inactivation curve to the hyperpolarizing direction. Both brief and long conditioning pulses could produce a use-dependent block of 1389-S. These results suggest that 1389-S had a higher affinity to the inactivated than to the rested state under steady state conditions and had a higher affinity to the activated state during train pulses as well as to the inactivated state, making channels unavailable for conduction upon activation.

Animals↗
PubMed1990

Lymphotoxin production by regional lymph node lymphocytes in patients with uterine cervical cancer.

The cytotoxin production by regional lymph node cells was examined in 25 patients with uterine cervical cancer and 10 patients with uterine myoma. The patients in stage I had significantly increased spontaneous release of cytotoxins compared with that in stages II, III, and IV. The spontaneous release in stages III and IV was markedly reduced. There was no difference in the release of cytotoxins from peripheral blood lymphocytes between cancer patients and patients with myoma or healthy controls. The cytotoxin production by lymph node cells was increased in stage III by stimulating with formalin-fixed QG-K cells derived from uterine cervical cancer, but not in stages I and II. Almost all of the cytotoxic activity of cytotoxin was abrogated by antilymphotoxin antibody. However, the cytotoxin activity was partially inhibited by anti-tumor necrosis factor antibody. These results suggest that cytotoxins released from the regional lymph node cells of uterine cancer patients are derived from, most of all, lymphotoxin.

Adult↗
PubMed1990

Disappearance of thyroid-stimulation blocking antibody by glucocorticoid therapy in a patient with primary myxedema who developed aortitis syndrome during L-thyroxine supplementation.

A 39-year-old woman with primary myxedema, who had the potent activities of thyrotropin-binding inhibitory immunoglobulins (TBII) and thyroid-stimulation blocking antibodies (TSBAb), developed aortitis syndrome about 6 months after the initiation of L-thyroxine (L-T4) supplementation. A 35 mg daily dose of prednisolone for aortitis syndrome was initiated, and the dose was gradually reduced. TBII and TSBAb activities were gradually decreased, and both reached normal levels (7.7% and 10.1%, respectively) 3 months after the initiation of prednisolone. Therefore, dose of L-T4 was gradually reduced, and L-T4 supplementation was stopped. Subsequently, however, recurrence of hypothyroidism was not observed. These observations indicate the possibility that hypothyroidism remits with disappearance of TBII and TSBAb activities in not only neonatal cases but also adult cases.

Adult↗
PubMed1990

Oral and intravenous glucose-induced insulin secretion in hyperthyroid patients.

To elucidate glucose intolerance in hyperthyroidism, insulin response to oral (75 g) and intravenous (IV) (20 g) glucose administration was investigated in 18 hyperthyroid patients and six normal control subjects. In oral glucose tolerance tests (OGTT), plasma insulin and C-peptide levels in hyperthyroid patients were not significantly different from that in controls; however, an impaired blood sugar response was observed in hyperthyroid patients. In IVGTT, blood sugar, plasma insulin, and C-peptide levels were significantly higher in hyperthyroid patients than in controls. Insulin secretion in proportion to blood sugar stimulus (the sum of increment in insulin divided by the sum of increment in blood sugar after glucose load, sigma delta IRI/sigma delta BS) in IVGTT was similar in hyperthyroid patients and controls; however, that in OGTT was significantly lower in hyperthyroid patients. After thyroid function tests had returned to normal by treatment with thiamazole, glucose tolerance and sigma delta IRI/sigma delta BS in OGTT were almost normalized. These results indicate that decreased insulin secretion after oral glucose may have an important role in abnormal oral glucose metabolism in hyperthyroidism.

Administration, Oral↗