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Biomedical subjects

M Murayama

Publications and source records attributed to M Murayama.

At least 253 records · Page 14Linked to original sources
PubMed1985

[Image diagnosis of adrenal disorders--I. CT images of control subjects and image diagnosis of primary aldosteronism].

The shape and size of the adrenals in control subjects without adrenal disorders were studied by computed tomography (CT), and a comparative assessment of diagnostic values of ultrasonography (US) by electronic linear scanner, CT, and adrenal scintigraphy was made on 9 patients with primary aldosteronism. Adrenal imaging by scintigraphy was performed on the 5th and 6th day, or further on the 7th day after the injection of 1 mCi of Adosterol. CT findings of the adrenals in control subjects: Eighty-two % of 100 control right adrenals, and 89% of 100 control left adrenals were detected by CT. Seventy-seven % of the right adrenals were in linear-shape, and the others were in V-shape. The shape of the left adrenals could be classified into triangular-shape (54%), Y-shape (28%) and V-shape (18%). The mean width and thickness of the right adrenals were 28.6 +/- 7.5 mm (M +/- SD) and 3.8 +/- 1.4 mm, respectively. Those of the left ones were 19.4 +/- 5.5 mm and 5.3 +/- 1.8 mm. Image diagnosis of primary aldosteronism: In 2 out of 3 patients examined by US, aldosteronomas were detected. In these 2 patients, one had 2 adenomas 2.8 X 1.7 X 1.2 cm and 1.0 X 1.0 X 2.0 cm in size, and the other had one adenoma 0.8 X 1.0 X 2.0 cm in size. On adrenal scintiscanning under dexamethasone pretreatment (DP), the isotope uptake of aldosteronoma was still seen with the disappearance of the contralateral adrenal in 7 out of 9 cases. In these 7 cases, the laterality of the tumor was confirmed. In one of the remaining 2 cases, the bilateral adrenal images were obtained regardless of DP. In the other case, of which aldosteronoma was the smallest (0.6 X 0.6 X 0.8 cm), the image of the affected adrenal with adenoma as well as the contralateral adrenal disappeared under DP. CT delineated all aldosteronomas in 8 cases examined including 2 cases in which adrenal scintiscanning failed to elucidate the localization of aldosteronoma. These results indicated that the combination of these 3 new image diagnostic methods was available for the detection of aldosteronomas of various sizes.

Adenoma↗
PubMed1985

Effect of cyclic AMP on mesaconitine-induced analgesia in mice.

The effects of cyclic AMP, dibutyryl cyclic AMP, theophylline, isoproterenol and propranolol on mesaconitine (MA)-induced antinociception in mice were investigated employing the tail flick and acetic acid-induced writhing methods for the evaluation of antinociceptive activity. MA-induced antinociception was significantly potentiated by cyclic AMP and dibutyryl cyclic AMP. The phosphodiesterase inhibitor theophylline also significantly potentiated the MA-induced antinociception. Further, MA-induced antinociception was markedly increased by a beta-adrenoceptor agonist, isoproterenol, and reduced by a beta-adrenoceptor antagonist, propranolol. These results suggest that the antinociceptive action of MA is potentiated through cyclic AMP and stimulation of the central beta-adrenergic system.

Aconitine↗
PubMed1985

Mechanism of the antinociceptive action of mesaconitine: participation of brain stem and lumbar enlargement.

The antinociceptive action of mesaconitine (MA) microinjected into the nucleus reticularis gigantocellularis (NRGC), the nucleus reticularis paragigantocellularis (NRPG), the periaqueductal gray (PAG) or the lumbar enlargement was investigated in rats by use of the tail immersion test. In addition, the effects of beta-adrenoceptor antagonists and an alpha-adrenoceptor antagonist administered intrathecally (i.t.) on the antinociceptive action of MA given into the NRPG were also examined by the tail immersion test. MA (50, 100 ng per rat) microinjected into the NRGC, the NRPG, and PAG and the lumbar enlargement increased the response latency in rats in a dose-dependent fashion. MA (50 ng per rat) microinjected into neighbouring sites, the nucleus reticularis parvocellularis, the nucleus originis nervi abducentis and the fasciculus longitudinalis medialis, elicited no significant effect. Intrathecally administered propranolol (1 and 5 micrograms per rat), atenolol (1 and 5 micrograms per rat) and IPS-339 (1 and 5 micrograms per rat) remarkably inhibited the increase of the response latency induced by MA (50 ng per rat) given into the NRPG. Intrathecally administered phenoxybenzamine (1 and 5 micrograms per rat) inhibited the increase of the response latency induced by MA (50 ng per rat) injected into the NRPG but to a lesser extent than the beta-adrenoceptor antagonists. It is concluded that the NRGC, the NRPG, the PAG and the lumbar enlargement are involved in the sites of the antinociceptive action of MA and that the antinociceptive effect of MA administered into NRPG is elicited by activation of the inhibitory noradrenergic neurones from the NRPG in particularly via beta-receptor-mediated effects of noradrenaline.

Aconitine↗
PubMed1985

Biopharmaceutical evaluation of methylcellulose as an excipient for nitroglycerin tablets.

To examine the bioavailability of nitroglycerin in sublingual tablet, 5 healthy adult volunteers underwent simultaneous sublingual administration of a tablet prepared with methylcellulose and a tablet prepared with lactose containing 0.15 mg of nitroglycerin and 0.15 mg of nitroglycerin-15N3, respectively. In 4 of 5 volunteers, no difference in plasma concentration determined by gas chromatography-mass spectrometry (GC-MS) was observed between 2 tablets described above, so it was well accepted that nitroglycerin in tablets prepared with methylcellulose had a similar bioavailability to that in tablets prepared with lactose. The simultaneous administration of the 2 nitroglycerin tablets to a healthy volunteer, one of which containing the drug labeled with a stable isotope followed by GC-MS assay, seems to be the most suitable method for a precise comparison of bioavailability of the formulations.

Adult↗
PubMed1984

Mechanism of analgesic action of mesaconitine. I. Relationship between analgesic effect and central monoamines or opiate receptors.

The contribution of the central monoamines and the opiate receptor to mesaconitine (MA)-induced analgesia was investigated by means of pharmacological and neurochemical methods in which morphine (Mor) was used for comparison. The analgesic action of MA (i.c.) determined by the acetic acid-induced writhing method and the tail flick method was dose-dependent, indicating that its activity is elicited through the central nervous system. MA-induced analgesia was decreased by alpha-methyl-p-tyrosine (alpha-MT), 6-hydroxydopamine, diethyldithiocarbamate, disulfiram and reserpine, and increased by methamphetamine and norepinephrine (NE). The mode of action of MA was similar to that of Mor except for the results obtained upon combined administration with 1-dopa, dopamine, alpha-MT or chemicals related to 5-hydroxytryptamine. In addition, MA promoted the alpha-MT-induced decrease in NE levels in hippocampus, medulla oblongata plus pons and spinal cord. Levallorphan did not affect the analgesic activity of MA, showing that its activity is not mediated via the opiate receptors. Consequently, it is concluded that the analgesic activity mediated by MA is closely related to responses involving the central catecholaminergic system, in particular, the noradrenergic system.

Aconitine↗
PubMed1984

Ex vivo human platelet aggregation induced by decompression during reduced barometric pressure, hydrostatic, and hydrodynamic (Bernoulli) effect.

Decompression of human platelet-rich plasma (PRP) in siliconized glass or plastic to 380 mm Hg for 3 hours at 38 degrees C produced platelet aggregation independent of pO2. Aggregation also took place when PRP was compressed to 8,000 PSI and then decompressed slowly to one atmosphere (14.7 PSI) without gas bubble formation. Platelets also aggregated when plasma was decompressed hydrodynamically (Bernoulli effect) at room temperature. It was also found that the drugs piracetam (2-oxypyrolidine acetamide) and pentoxifylline (1-(5-oxohexyl)-theobromine) at 0.5 and 1.0 mM prevent thrombocyte aggregation. Implications for mountain sickness are discussed.

Atmospheric Pressure↗
PubMed1984

Stimulating actions on ribonucleic acid biosynthesis of aconitines, diterpenic alkaloids of Aconitum roots.

Mesaconitine (MA) significantly stimulated the incorporation of 5-[3H]-orotic acid into liver nuclear RNA 16 h after its administration. MA exhibited the strongest activity among the aconitine alkaloids. This stimulatory effect of MA was inhibited by actinomycin D, but the incorporation ratio of 5-[3H]orotic acid in the combined treatment group with MA and actinomycin D was significantly higher than that in the single treatment group with actinomycin D. MA also increased the incorporation of 5-[3H]orotic acid into polysomal RNA in mouse liver. When MA was added to the RNA polymerase (EC 2.7.7.6) preparation obtained from rat liver, the increase of the enzyme activity was weak. While RNA polymerase preparation from the liver of rats, which were previously treated with MA, elicited increased incorporation of [3H]cytidine monophosphate into RNA as compared with that from the livers of normal rats. Accumulated data indicate that aconitine alkaloids, in particular MA, accelerate liver RNA synthesis mainly by the increase of RNA polymerase.

Aconitine↗
PubMed1983

[Thyroid hormone autoantibodies in Hashimoto's disease and Graves' disease].

We previously reported the presence of thyroid hormone autoantibodies (THAA) in the sera from three (2 Hashimoto's thyroiditis, 1 Hashimoto's thyroiditis suspected) out of four sisters in a family and one patient with Graves' disease during treatment with methimazole (MMI). According to the investigations of the binding of labelled thyroid hormones, endogenous and/or therapeutic thyroid hormones interfered with their binding with THAA. This interference, however, was excluded when the sera were acidified with a 0.05M glycine-HCl buffer (pH 2.1) and all the liberated thyroid hormones were absorbed into dextrancoated charcoal. In this study, the specific binding of the tracer thyroid hormone to gamma-globulin was examined in hormone-stripped sera from patients with Hashimoto's disease (pretreatment n = 29; L-T4 treatment n = 9) and Graves' disease (pretreatment n = 21; MMI or propyl-thiouracil (PTU) treatment n = 22; MMI or PTU treatment after 131I therapy n = 8) under conditions in which the difference of the concentration of gamma-globulin in each case did not influence the binding. None of the patients examined had increased binding of 125I-T3 with their gamma-globulin. Elevated binding of 125I-T4 was found in sera obtained from 3 patients (2 pretreatment, 1 L-T4 treatment) with Hashimoto's disease and 7 patients (1 pretreatment, 4 MMI or PTU treatment, 2 MMI or PTU treatment after 131I therapy) with Graves disease. Seven (2 Hashimoto's disease, 5 Graves disease) out of these 10 patients with anti-T4 autoantibodies had antibodies against thyroglobulin (Tg) as measured by the hemagglutination method. Titers of anti-T4 autoantibodies and anti-Tg antibodies did not correlate. In Graves disease, anti-T4 autoantibodies were detected during the treatments in sera from 5 (3 MMI or PTU treatment, 2 MMI or PTU treatment after 131I therapy) out of 16 patients (10 MMI or PTU treatment, 6 MMI or PTU treatment after 131I therapy) who had anti-Tg antibodies. On the other hand, anti-T4 autoantibodies prior to the medication could not be found in sera from 5 patients with positive anti-Tg antibodies. From these results, it is suggested that antithyroid drugs and/or 131I therapy might induce the production of THAA in patients with Graves disease through the deterioration of immunological tolerance and/or through the modification of the Tg molecule.

Adult↗
PubMed1983

Restoration of phagocytosis and oxidative metabolism by Piracetam in failing human neutrophils: a qualitative assessment.

By the use of immunobeads, a convenient clinical laboratory test is available which detects, in metabolically stressed leukocytes, failing or absent phagocytosis and/or impaired to absent oxidative metabolic activity. Furthermore, it has been demonstrated that Piracetam, 2-oxo-pyrrolidine acetamide, will restore such compromised neutrophils to normal functional status. In 4 of 19 patients, all with a variety of serious diseases, a range from impaired to total failure of neutrophilic phagocytic and metabolic oxidative activities was detected by the test. Piracetam, as shown by qualitative methods, restored to optimal activity the two impaired neutrophil functions in these 4 patients. Quantitative techniques are available currently to establish the beneficial effect of Piracetam on such defective neutrophils. Piracetam merits additional study to determine its efficacy in enhancement of restorative effects on compromised neutrophils which have been observed. The clinical promise of this investigation offers benefit to some patients now jeopardized by certain stressful diseases in part due to agonal failure of neutrophils.

Adolescent↗
PubMed1983

Clinical significance of daily work angina and its relation to unstable angina.

The incidence of angina pectoris was studied in 247 patients having a long history of this disorder. Angina of effort (EA), angina at rest (RA) and daily work angina (DA) occurred in 91, 57 and 29% of these cases, respectively. Sixty-three percent of the cases had histories of more than 2 types of angina, EA, RA and DA. DA occurred in 39, 25 and 27% of the cases with new EA, new RA and changing pattern of unstable angina (UA), respectively, and it occurred coincidentally with the period of UA. Therefore, DA was considered as a pattern of UA. UA could not be classified well according to the precipitating factors or spontaneous occurrence and its classification according to a new occurrence or worsening condition is clinically useful for predicting a short-term prognosis. Ischemic ST changes seemed to be preceded by an increase of heart rate and blood pressure in micturition angina, although these increases were significantly lower than those in exercise-induced angina. Beta-blocking agents were ineffective but calcium antagonists were effective for micturition angina. Voiding is not essential for provoking angina, since strain alone could induce angina. Common pathophysiological status, such as coronary arterial spasm, may underlie all types of DA.

Activities of Daily Living↗
PubMed1983

Exercise test in variant form of angina pectoris. Comparison of the results with spontaneous attacks.

Exercise tests were performed in 14 patients with untreated variant angina with frequent spontaneous attacks and in 15 patients after treatment abolished the attacks. (1) Anginal attacks associated with ST elevation were induced by exercise in 79% of untreated patients. By contrast, ST elevation was not observed in treated patients and ST depression was induced in 53% of the cases. (2) Exercise-induced ST elevation in untreated patients was shown in the same leads as the spontaneous attacks. (3) Exercise-induced ST elevation appeared initially during the recovery phase after exercise in 36% of untreated patients. Exercise-induced ST depression appeared during or immediately after exercise. (4) The reproducibility of exercise-induced ST elevation was low with repeated tests at different stages, but exercise-induced ST depression was consistently observed. (5) The exercise-induced ST depression and lack of ST changes in treated patients were highly suggestive of the presence and absence of organic coronary artery disease, respectively. However, the exercise-induced ST elevation in untreated patients did not differentiate between the presence or absence of organic stenosis of the coronary arteries. The results of exercise tests vary with the stage of variant angina. It is suggested that a coronary arterial spasm is a trigger mechanism for exercise-induced angina in cases of variant angina with frequent spontaneous attacks.

Adult↗
PubMed1983

[Arrhythmia].

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Arrhythmias, Cardiac↗
PubMed1982

Pacing echocardiography: regional wall motion, left ventricular dimension and R wave amplitude in patients with angina pectoris.

In view of the fact that stable echocardiograms are easily obtained during atrial pacing, pacing echocardiography was performed to evaluate the usefulness for detecting regional wall motion abnormalities during pacing-induced ischemia and to investigate the relationship between changes in the R wave and left ventricular dimension. The patients were 12 cases of angina pectoris (10 of coronary artery disease; CAD, and 2 of coronary patent aortic valvular disease; AVD) and 6 control cases. Simultaneous recording of two-dimensional and M-mode echocardiograms and electrocardiograms was done before, during and after the atrial pacing at increasing heart rate until angina appeared or the heart rate of at least 140/min was reached. In 12 angina cases, angina and ST depression were induced in 10 and 11, respectively. Excursion of the interventricular septum (IVS) decreased during pacing-induced ischemia in 6 of 7 CAD cases, in which the left anterior descending coronary artery was significantly stenosed (more than 75%). Excursion of the left ventricular posterior wall (LVPW) decreased during pacing-induced ischemia in 4 of 7 CAD cases, in which the vessels giving rise to posterior descending coronary artery were significantly stenosed (more than 75%). In 2 AVD cases, excursion of both IVS and LVPW decreased during ischemia. Left ventricular end-diastolic dimension (LVEDD) increased in only 2 angina cases, although R wave amplitude increased in 6 angina cases.

Adult↗
PubMed1982

Effects of acute changes in left ventricular size on surface potential in man.

Effects of cardiac size on surface potential magnitude were investigated by induction of acute changes in ventricular dimensions by rapid atrial pacing in 17 cases with ischemic heart disease (IHD) and in 15 cases without IHD. Left ventricular end-diastolic dimensions (LVDd), estimated by echocardiography, decreased along with certain changes in surface potential magnitude during atrial pacing in each case. A positive correlation between LVDd and the amplitudes of RV5, RX, and the maximum spatial QRS magnitude was observed in most of the cases and might be explained by changes in distance between the heart and the chest electrode and/or the Brody effect. However, an inverse correlation was observed in 4 of 17 cases with IHD, and could not be explained by these factors. Other factors, such as changes in the ventricular activation sequence, should be considered as the mechanism.

Adult↗
PubMed1982

[Noninvasive evaluation of cardiac involvements and left ventricular function in schoolchildren with the history of mucocutaneous lymph node syndrome].

Mucocutaneous lymph node syndrome (MCLS) in the young has been known to have coronary aneurysms, and then it has been recently suspected as a cause of premature atherosclerosis and cardiomyopathy. Thirty-three schoolchildren who suffered from MCLS were studied to evaluate cardiac involvements and left ventricular function using two-dimensional (2-D) echocardiograms and submaximal stress test. Fifteen normal schoolchildren were studied as normal control. All these MCLS children were asymptomatic and had no significant findings in routine chest X-ray and electrocardiographic examinations. According to submaximal stress test, 8 cases showed a J type ST depression of only 0.5--1.0 mm, and there were no positive cases. Using 2-D echocardiograms, the left coronary artery was detected in 85% and the right coronary in 27%. One case showed an aneurysm of the left coronary artery. However, none of them showed abnormal left ventricular wall motion or the wall motion abnormality compatible with cardiomyopathy. There were no significant differences between MCLS and normal control in ejection fraction, mean VCF, diastolic descent rate of the anterior mitral valve, D/S ratio of the left ventricular wall, and Weissler's index (PEP/ET). These findings suggested that 1) most of MCLS schoolchildren do not have obvious cardiac involvement and their left ventricular function is within normal limits, 2) because of its low sensitivity, submaximal stress test is not so useful in screening coronary lesions, and 3) the 2-D echocardiogram works not only in detecting coronary aneurysms but also in evaluating left ventricular function.

Adolescent↗