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Biomedical subjects

J Yamazaki

Publications and source records attributed to J Yamazaki.

At least 91 records · Page 5Linked to original sources
PubMed1995

[Usefulness of 123I-MIBG myocardial SPECT in patients with hematologic malignancies with chemotherapeutic agent-induced cardiomyopathy].

In 59 patients with hematologic malignancy undergoing chemotherapy regimens including adriamycin (ADR), myocardial imaging was performed by SPECT with 123I-metaiodobenzylguanidine (MIBG) to detect cardiac sympathetic nerve abnormalities. SPECT imaging was performed 20 min and 4 hr after intravenous injection of 123I-MIBG, and the washout rate (WR) for the entire left ventricle was calculated. Then the relationship of the WR to the total dose of ADR, the left ventricular ejection fraction, and the frequency of arrhythmias was evaluated. It was found that the WR was related to the total dose of ADR, suggesting that it is a useful parameter for cardiac sympathetic nerve damage. As the WR increased, the frequency of ventricular arrhythmias also increased. The WR was usually normalized 3-6 months after the discontinuation of ADR. In patients with a WR > or = 50%, however, prolonged follow-up was required. In conclusion, the WR on 123I-MIBG myocardial SPECT scans may be useful as a parameter for predicting cardiac toxicity requiring the discontinuation of ADR or dose reduction.

3-Iodobenzylguanidine↗
PubMed1995

[Trial of a treatment for lymph node metastases in patients with breast cancer using aclarubicin bound to activated carbon particles].

A new dosage formulation (ACR-CH), composed of aclarubicin (ACR) bound to fine activated carbon particles, was developed for the treatment of lymph node metastases in patients with breast cancer. In a mice experimental model, ACR-CH had superior therapeutic effects on lymph node metastases compared to the same dose of ACR aqueous solution. In clinical trials, patients with breast cancer received a local injection of 10 mg/person of ACR in the form of ACR-CH or ACR aqueous solution just before mastectomy. In the regional lymph nodes removed by the operation, the ACR concentration of 40.7 micrograms/g in patients given ACR-CH was higher than the 25.1 micrograms/g in patients given ACR aqueous solution, whereas in blood plasma the concentration was higher in patients given ACR aqueous solution than in those given ACR-CH.

Aclarubicin↗
PubMed1995

[Development of 5-fluorouracil incorporated in microspheres for peritoneal carcinomatosis--animal experiments].

A new dosage formulation (5-FU-MS), composed of 5-fluorouracil (5-FU) incorporated in polyglactin microspheres, was studied by animal experiments, which revealed the following results. Intraperitoneal 5-FU-MS delivered greater concentrations of 5-FU for longer periods selectively to the intraperitoneal tissues, whereas it delivered a lower concentration to the blood plasma, than 5-FU solution did in rats. In mice, the 50% lethal dose value of intraperitoneal 5-FU-MS was 535 mg/kg. The toxicity of 5-FU-MS was less than 1/2 that of intraperitoneal 5-FU solution, of which the 50% lethal dose value was 242 mg/kg. Intraperitoneal 5-FU-MS at 200 mg of 5-FU/kg improved the survival curve of mice with peritoneal carcinomatosis better than the identical dose of 5-FU solution.

Animals↗
PubMed1995

Intravenous administration of vancomycin is ineffective against bacteremia following tooth extraction.

The incidence of transient bacteremia after tooth extraction without antimicrobial prophylaxis has been reported was high as 69.2%; that with intravenous ampicillin as 4.2% (1, 2). Currently, we tested a regime of vancomycin that was recommended by the American Heart Association as prophylaxis for oral surgery patients who were allergic to penicillin and evaluated its effectiveness. Before the surgical procedures, we started an intravenous drip infusion of vancomycin. Ten of 26 patients became blood culture positive (38.5%). Seventeen strains of bacteria were isolated. The Minimum Inhibitory Concentrations (MICs) of vancomycin were lower than 3.13 micrograms/ml, with just one exception.

Anti-Bacterial Agents↗
PubMed1994

Hemodynamic and coronary vasodilative properties of a selective and full beta 1-adrenoceptor agonist, T-0509, in comparison with isoproterenol in anesthesized dogs.

Recently, the beta 1-adrenoceptor was shown to mediate direct coronary vasodilation independent of metabolic demand in canine arrested heart preparation. To investigate the beta 1-adrenoceptor-mediated direct vasodilation in a beating heart preparation, we compared coronary blood flow (CBF) and coronary sinus oxygen tension (PO2) in anesthetized open-chest dogs using a beta 1-selective agonist, T-0509. T-0509 (0.005-0.05 microgram/kg intravenously, i.v.) increased the maximal rate of increase in left ventricular pressure (LVdp/dtmax) and heart rate (HR) to an extent similar to that induced by isoproterenol (ISO) without decreasing diastolic blood pressure (DBP). A beta 1-adrenoceptor antagonist, (-)-bisoprolol (10 micrograms/kg), but not a beta 2-adrenoceptor antagonist, ICI 118,551 (30 micrograms/kg), inhibited the T-0509-induced increase in LVdp/dtmax and HR. Thus, T-0509 showed selective beta 1 stimulation at the doses used. T-0509 also caused beta 1-selective relaxation in isolated coronary arteries. ISO increased both CBF and PO2. The early phase of the increase in CBF and the concurrent increases in PO2 were inhibited by ICI 118,551, whereas the late phase of the increase in CBF was inhibited by (-)-bisoprolol. T-0509 increased CBF, and this increase was inhibited by (-)-bisoprolol. A slight but significant increase in PO2 induced by T-0509 was not altered by these doses of the antagonists. Our results indicate that the T-0509-induced increase in CBF is due mainly to an indirect effect on myocardial beta 1-adrenoceptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-1 Receptor Agonists↗
PubMed1994

[Clinical usefulness of 123I-MIBG myocardial SPECT in patients with adriamycin-induced cardiomyopathy].

In 29 patients who had been administrated adriamycin (ADR) for the treatment of hematopoietic malignancies, myocardial SPECT was performed 20 minutes and 4 hours after an intravenous dose of 123I-metaiodobenzylguanidine (MIBG). Findings of the myocardial SPECT were compared with the total dose of ADR, ejection fraction (EF) and left ventricular wall motion, as assessed by ultrasound echocardiography. The mean total dose of ADR was 329.3 mg/m2 (range, 150-550 mg/m2). 1) Although the cardiac function was normal, the washout rate (WR) of MIBG was high in 75% of the patients whose MIBG myocardial SPECT showed abnormality on ADR, suggesting the presence of adrenergic nerve disorder. 2) The total dose of ADR was significantly correlated with WR of MIBG (p < 0.001). Consequently, WR of MIBG may be an index which reflects adrenergic nerve disorder in the myocardium earlier than EF. 3) It was suggested that adrenergic nerve disorder was involved in pathogenesis of myocardial complications associated with ADR administration. In summary, MIBG myocardial SPECT could be a useful test for determining a dosage regimen of ADR therapy of individual patients.

3-Iodobenzylguanidine↗
PubMed1994

[A case of pulmonary thromboembolism with pulmonary hypertension with marked improvement by oral PGI2 analogue].

The patient was a 71-year-old man with dyspnea and bilateral leg edema. He was admitted to our hospital with worsening of dyspnea and had received therapy for chronic heart failure in another hospital. On admission, chest X-ray film revealed dilatation of the cardiac silhouette (CTR: 58%). Electrocardiogram showed atrial fibrillation and negative T wave in II, III, and aVF. Cardiac arteriogram showed no organic lesions, but pulmonary hypertension, pulmonary artery pressure of 60/21/34 mmHg, right ventricular pressure of 40/9/20 mmHg were recognized in pulmonary hemodynamics. The diagnosis of chronic pulmonary thromboembolism was made on the basis of pulmonary arteriogram findings and multiple defects of lung perfusion scintigram. After administration of oral PGI2 analogue for one month, lung perfusion scintigram and right cardiac pressure were markedly improved.

Administration, Oral↗
PubMed1994

Evaluation of the efficacy of nicorandil in patients with ischemic heart disease by exercise Tl-201 myocardial SPECT.

The effect of nicorandil on myocardial perfusion in ischemic heart disease was studied using exercise-load Tl-201 myocardial SPECT (Ex-SPECT). ExSPECT was carried out in 12 patients with previous myocardial infarction (OMI) and 9 with angina pectoris (AP) before and after administration of nicorandil 15 mg/day, for three or more weeks; %Tl uptake and the washout rate in infarcted or ischemic areas were calculated from short axial images using the Bull's eye method. In the OMI group, %Tl uptake and washout rates in the infarction areas improved significantly from 52.4% and 0.25 before nicorandil to 60.4% and 0.38 after nicorandil. In the AP group, too, %Tl uptake and washout rates showed a significant improvement from 56.9% and 0.10 before to 69.1% and 0.33 after administration of nicorandil. Six subjects who had not received the drug, and who showed negative washout rates, had high improvement rates when nicorandil was administered, suggesting that the drug could increase myocardial perfusion during exercise loading as well as suppressing coronary spasm. Ex-SPECT was carried out in 4 subjects before and after the administration of nicarandil and after subsequent surgical treatment (PTCA or CABG) and the effects of the two therapies were compared. The washout rate was improved from 0.01 to 0.34 by the administration of nicorandil, and a notable increase in coronary artery blood flow was achieved compared to the level after surgical treatment, i.e. 0.50. It is concluded that normal dosages of nicorandil have a powerful direct effect of dilating the coronary arteries without any influence on preload or afterload.

Adult↗
PubMed1994

[A case of rheumatoid arthritis associated with agranulocytosis during bucillamine treatment].

Bucillamine has been reported to have beneficial effects in rheumatoid arthritis. This report concerns a case of RA in which agranulocytosis developed while on a course of bucillamine. A 52-year-old female with RA developed a rapid fall in white blood cell count after 4 weeks of bucillamine treatment at daily dose of 50 mg. Agranulocytosis was diagnosed (WBC 1300/mm3, granulocytes 5%). The administration of bucillamine was halted and she was treated with only prophylactic antibiotic regime. The peripheral granulocyte count result rapidly reversed within 3 days after discontinuation of the bucilamine treatment. Anti-leukocyte antibody was detected by the leukocyte lysis phenomenon method during the period of agranulocytosis. And high intrinsic G-CSF activities were detected in the patient serum before the recovery period of agranulocytosis. Agranulocytosis is a rare side effect of bucillamine but it is potentially more harmful than other side effects. In treatment with bucillamine, therefore, the drug should be carefully administered and regular blood examinations carried out to prevent the occurrence of this side effect.

Agranulocytosis↗
PubMed1994

[Clinical meaning of 123I-MIBG myocardial SPeCT in patients with dilated cardiomyopathy].

MIBG-myocardial SPECT was performed on patients with dilated cardiomyopathy (DCM) undergoing treatment with beta blocker (Nipradilol). The findings of MIBG-myocardial SPECT were compared with the changes in cardiac function obtained by echocardiograms. The patients enrolled in the study were seven males who has been diagnosed as definitely suffering from DCM according to diagnostic guidelines provided by the Ministry of Health and Welfare. The patients were aged 57.5 +/- 10.2 years. Following intravenous administration of 111 MBq (3 mCi) of MIBG, myocardial SPECT was taken 20 minutes, and 4 hours later. The washout rate of the left ventricular wall was higher in the unchanged group (40.7 +/- 1.2%) than in the improved group (30.3 +/- 6.1%). Both the early and delayed images showed higher extent and severity scores for the unchanged group than for the improved group. A correlation of LVEF with the washout rates was demonstrated (r = -0.819, p < 0.05). A correlation was also observed between the variations in LVEF before and after beta blocker therapy with the washout rates (r = -0.969, p < 0.01), MIBG-myocardial SPECT suggested possibility of the evaluation of severity and prognosis in the patients with DCM.

3-Iodobenzylguanidine↗
PubMed1993

Study of the efficacy of nicorandil in patients with ischaemic heart disease using Exercise-T1-201 myocardial tomography.

The effect of nicorandil on myocardial perfusion in ischaemic heart disease has been studied using exercise-load T1-201 myocardial SPECT (Ex-SPECT). Ex-SPECT was carried out in 12 patients with previous myocardial infarction (OMI) and 9 with angina pectoris (AP) before and after administration of nicorandil 15 mg/day, for three or more weeks; % T1 uptake and the washout rate in infarcted or ischaemic areas were calculated from short axial images using the Bull's eye method. In the OMI group, % T1 uptake and washout rates in the infarction areas improved significantly from 52.4% and 0.25 before nicorandil to 60.4% and 0.38 after it. In the AP group, too, % T1 uptake and washout rates showed a significant improvement from 56.9% and 0.10 before to 69.1% and 0.33 after administration. Six subjects who had not received the drug, and who showed negative washout rates, had high improvement rates when nicorandil was administered, suggesting that the drug could increase myocardial perfusion during exercise loading as well as suppressing coronary spasm. Ex-SPECT was done in 4 subjects before and after nicorandil and after subsequent surgical treatment (PTCA or CABG) and the effects of the two therapies were compared. The washout rate was improved from 0.01 to 0.34 by administration of nicorandil, and a notable increase in coronary artery blood flow was achieved compared to the level after surgical treatment, i.e. 0.50. It was concluded that, normal dosages of nicorandil have a powerful direct effect of dilating the coronary arteries without any influence on preload or afterload.

Adult↗
PubMed1993

Influence of composition of l-menthol-ethanol-water ternary solvent system on the transdermal delivery of morphine hydrochloride.

The influence of concentration of each component in l-menthol-ethanol-water ternary solvent system (MEW system) on the skin permeation of morphine hydrochloride (MPH) was investigated in hairless rats. The cumulative amount of MPH permeated through the excised abdominal skin over 8 h (Q-8) was selected as an index of skin permeability. With changing MPH concentration over a wide range from 0.01 to 10% in a MEW system (5% l-menthol and 40% ethanol), the values of Q-8 were proportional to MPH concentration. The concentration was fixed at 1% for the following experiments. For the effect of the concentration of l-menthol at 40% ethanol, the maximum Q-8 was observed at 5% l-menthol, and no greater enhancement of Q-8 was obtained by increasing l-menthol concentration above that. In the ethanol effect at 5% l-menthol, the maximum Q-8 was observed at 45% ethanol. When 2-propanol and methanol, which are more lipophilic and hydrophilic than ethanol, respectively, were used instead of ethanol, the maximum values of Q-8 were observed at 40 and 55%. The maximum values for Q-8 were obtained in the vicinity of the solubility of l-menthol in the MEW system in all cases, suggesting that the skin permeation enhancing effect of the system is dependent on the thermodynamic activity of l-menthol.

1-Propanol↗
PubMed1993

[Evaluation of myocardial viability in the infarcted areas by the improved myocardial perfusion after percutaneous transluminal coronary angioplasty].

Muscle viability in infarcted areas was evaluated based on the relationship between Tl myocardial scintigraphic findings and improvements in myocardial perfusion after percutaneous transluminal coronary angioplasty (PTCA) in 110 patients with old myocardial infarction (OMI). 1. Myocardial perfusion was improved in 95% of patients with redistribution in infarcted areas before PTCA, but in only 29% of patients without redistribution before PTCA. 2. The %Tl-uptake and the washout rate were significantly improved after PTCA in all patients with redistribution before PTCA with normal to dyskinesia of segmental wall motion. The %Tl-uptake of infarcted area after PTCA was greater than 50% in all patients. 3. The %Tl-uptake and the washout rate were significantly improved after PTCA in patients without redistribution before PTCA. However, the %Tl-uptake was not changed after PTCA in such patients with akinesia or dyskinesia of segmental wall motion. 4. Myocardial perfusion was improved late during prolonged follow-up after PTCA in 40% of patients without restenosis. Stunning of the myocardium is likely in these patients. 5. %Tl-uptake of more over 50% in patients with or without redistribution before PTCA indicates the presence of muscle viability. Muscle viability cannot be expected in the infarcted areas of patients without redistribution showing akinesia or dyskinesia of segmental wall motion. Patients without redistribution before PTCA include cases with underestimated ischemic lesion. The diagnosis of muscle viability by single photon emission computed tomography will be improved by including evaluation of segmental wall motion by echocardiography.

Aged↗
PubMed1993

[The usefulness of three dimensional imaging of the myocardium using three heads SPECT camera (PRISM-3000)].

The SPECT unit using a 3 heads camera (PRISM-3000) has an advantage over the conventional one head camera SPECT unit because it can complete full circle scans (360 degrees scans) within a short time, and because the non-circular orbit of the camera heads fitting the individual form of the body has improved the spatial resolution. In addition, the high speed data processing has reduced the time for scan, enabling the three dimensional imaging system clinically applicable. In the present study, this modern technique was used to examined the myocardium in patients with ischemic heart disease so as to evaluate it for usefulness and depict problem to be solved. In patients with myocardial infarction, images obtained with a PRISM-3000 machine could provide more objective information on infarcts than conventional images. In patients with angina pectoris, delayed images obtained 3 hours after exercise by the new method were superior to conventional ones in power of demonstrating redistribution. The setting of the threshold for ischemic lesions at 40-50% hampers the assessment of the severity of ischemia. A new program should be introduced to solve this problem.

Aged↗
PubMed1992

5-HT2/5-HT1C receptor-mediated facilitatory action on unit activity of ventral horn cells in rat spinal cord slices.

5-Methoxy-N,N-dimethyltryptamine (5-MeODMT) and 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) facilitate motoneuron excitability through 5-HT1C/5-HT2 receptors in rats. Using spinal cord slices prepared from adult rats, we recorded unitary cell discharges, evoked by local stimulation of the adjacent site, extracellularly in the motor nuclei of the ventral horn. 5-MeODMT, DOI, 5-hydroxytryptamine (5-HT), 8-hydroxy-2-(di-N-propylamino)tetralin (8-OH-DPAT) and tandospirone facilitated the probability of firing in the motor nuclei, with 5-MeODMT and DOI being the most potent. The effect of 5-MeODMT was significantly suppressed by ketanserin (a 5-HT2 receptor-selective antagonist), spiperone (a 5-HT1A/5-HT2 receptor antagonist) and cyproheptadine (a 5-HT1C/5-HT2 receptor antagonist), but not by 3-tropanyl-3,5-dichlorobenzoate (MDL 72222, a 5-HT3 receptor-selective antagonist) or pindolol (a 5-HT1A/5-HT1B receptor antagonist). This suggests that 5-HT2 and/or 5-HT1C receptors are involved in the facilitatory effects of 5-HT receptor agonists on the synaptic activity of ventral horn cells.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1992

Stimulatory and inhibitory effects of serotonergic hallucinogens on spinal mono- and polysynaptic reflex pathways in the rat.

The effects of two 5-HT-related hallucinogens on rat spinal mono- and polysynaptic reflex pathways in the rat were investigated. 5-Methoxy-N,N-dimethyltryptamine (5-MeODMT, 1 and 100 micrograms/kg, i.v.), an indolealkylamine agent, produced a dose-dependent decrease in the monosynaptic reflex, whereas 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI, 1-100 micrograms/kg), a phenylalkylamine agent, produced a dose-dependent increase in the monosynaptic reflex. Both agents increased the polysynaptic reflex. The 5-HT2 receptor antagonists ketanserin (100 micrograms/kg) and ritanserin (100 micrograms/kg) blocked the effects of DOI on the monosynaptic reflex but only partially blocked the 5-MeODMT-induced effect on the monosynaptic reflex. These antagonists inhibited the change in polysynaptic reflex, induced by DOI but not by 5-MeODMT. Neither propranolol (1 mg/kg) nor 3-tropanyl-3,5-dichlorobenzoate (MDL 72222, 1 mg/kg) antagonized the effect of either agent. 5-Methoxy-N,N-dimethyltryptamine and DOI increased the excitability of motoneurons and this effect was inhibited by ketanserin. These results indicate that the two types of hallucinogens possess both common and distinct characteristics, with regard to their action on the spinal reflex: (1) both increase the activity of motoneurons through 5-HT2 receptors but (2) only 5-MeODMT has an inhibitory action on the pathway of the monosynaptic reflex.

Amphetamines↗