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T Miyamae

Publications and source records attributed to T Miyamae.

At least 19 recordsLinked to original sources
PubMed1992

Transmitter-like 3,4-dihydroxyphenylalanine is tonically released by nicotine in striata of conscious rats.

Microdialysis and high performance liquid chromatography with an electrochemical detector were applied to compare the characteristics of nicotine-evoked release of endogenous 3,4-dihydroxyphenylalanine (DOPA) from striata of conscious rats and those of the release of dopamine (DA). Dialysates were collected every 20 min 3-8 h after the start of perfusion. Nicotine was perfused for 20 min through a probe. (+/-)-Nicotine (100-300 microM) constantly and repeatedly released DOPA and DA over a similar time course in a dose-dependent manner. The ratio of the DOPA and DA release evoked was approximately 1:3. The (+/-)-nicotine (200 microM)-induced DOPA release was mecamylamine (500 microM)-sensitive, tetrodotoxin (100 nM)-sensitive and Ca2+ (removal plus 12.5 mM Mg2+ addition)-dependent. The (+)-isomer produced no DOPA release. These characteristics of DOPA release were almost the same as those of DA release. Furthermore, mecamylamine alone inhibited the basal release of DOPA but not of DA. Nicotine released stereoselectively endogenous DOPA via nicotinic acetylcholine receptors from striata of freely moving rats in a manner similar to transmitter DA. These acetylcholine receptors function tonically for the release of DOPA. These findings are further support for our proposal that DOPA is an endogenous neuroactive substance.

Animals↗
PubMed1992

Effects of phenylalaninol on centrally induced gastric acid secretion.

The effects of phenylalaninol (D-isomer) on gastric acid secretion and gastric ulcer were studied in rats. The compound reduced the gastric acid secretion stimulated by intracisternal thyrotropin releasing hormone and intravenous 2-deoxy-D-glucose, but not that stimulated by subcutaneous carbachol or histamine. Phenylalaninol prevented stress- and indomethacin-induced gastric ulcers. We conclude that phenylalaninol inhibits ulcer formation mainly by central inhibition of gastric acid secretion.

Animals↗
PubMed1992

[Right ventricular volume determination by continuous 81mKr infusion and 99mTc blood pool imaging].

Our newly developed radionuclide method for the calculation of right ventricular (RV) volume was examined in this study. Using a semi-geometric count-based method, volume can be measured by the following equation: Cv = Cm/(L/d). V = (Ct/Cv) x d3 = (Ct/Cm) x L x d2. (V = volume, Cv = voxel count, Cm = the maximum count of a container, Ct = the total count of the container, L = maximum length of the image of the container obtained from a direction perpendicular to the direction where the count data were collected, and d = pixel size.) A phantom study was performed by setting a cylindrical container in a system which circulated 5 liters of water per minute. 81mKr solution was infused continuously into the container, and images of the container were collected for one minute. Cm and Ct were obtained and, because the container was cylindrical, the maximum width of the image of the container was measured as L. The volume of the container was calculated using the above equation. The container's true volume and the volume measured by this method showed a good correlation with r = 0.997 (n = 13, p < 0.001). This theorem was applied to RV images obtained in the 30 degree right anterior oblique position by continuous infusion of the 81mKr solution. Multiple gated acquisition was performed and RV end-diastolic maximum counts and total counts were obtained. The RV maximum width was measured as L on the end-diastolic cardiac pool image with 99mTc-D-HSA collected in the 40 degree left anterior oblique position.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Left ventricular volume determination by first-pass radionuclide angiocardiography using a semi-geometric count-based method].

A new radionuclide technique for the calculation of left ventricular (LV) volume by the first-pass (FP) method was developed and examined. Using a semi-geometric count-based method, the LV volume can be measured by the following equation: CV = CM/(L/d). V = (CT/CV) x d3 = (CT/CM) x L x d2. (V = LV volume, CV = voxel count, CM = the maximum LV count, CT = the total LV count, L = LV depth where the maximum count was obtained, and d = pixel size.) This theorem was applied to FP LV images obtained in the 30-degree right anterior oblique position. Frame-mode acquisition was performed and the LV end-diastolic maximum count and total count were obtained. The maximum LV depth was obtained as the maximum width of the LV on the FP end-diastolic image, using the assumption that the LV cross-section is circular. These values were substituted in the above equation and the LV end-diastolic volume (FP-EDV) was calculated. A routine equilibrium (EQ) study was done, and the end-diastolic maximum count and total count were obtained. The LV maximum depth was measured on the FP end-diastolic frame, as the maximum length of the LV image. Using these values, the EQ-EDV was calculated and the FP-EDV was compared to the EQ-EDV. The correlation coefficient for these two values was r = 0.96 (n = 23, p less than 0.001), and the standard error of the estimated volume was 10 ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Volume↗
PubMed1991

Collateral pathways observed by radionuclide superior cavography in 70 patients with superior vena caval obstruction.

Schematic representations of collateral pathways that have developed in association with superior vena caval obstruction have been established in studies using radionuclide superior cavography (RNSC). However, these were hampered by the poor resolution of earlier scintillation cameras. Using a modern scintillation camera, we performed RNSC in 70 patients with obstruction of the superior vena caval system, and examined the differences in collateral pathways in the presence or absence of obstruction of the azygos vein. RNSC visualized the site of obstruction and collateral pathways far more readily than in prior studies. When the orifice of the azygos vein was not obstructed, collateral flow drained into the azygos system. When it was obstructed, however, the collaterals drained into the inferior vena caval system. An important collateral pathway comprising the contralateral brachiocephalic vein and the jugular venous arch was also found, which has not previously been reported. Our diagrams of collateral circulation may provide a means of determining the site of obstruction in the superior vena caval system by RNSC.

Adult↗
PubMed1991

[Thallium-201 myocardial scintigraphy after intravenous infusion of adenosine triphosphate disodium: a preliminary study in the diagnosis of coronary artery disease].

The feasibility and safety of thallium-201 myocardial scintigraphy after the intravenous infusion of adenosine triphosphate disodium (ATP) (Adetphos, Kowa) were studied in eight patients with angina pectoris and/or old myocardial infarction. Coronary arteriography (CAG) was performed by the conventional method in all patients. ATP was infused for 5 min and thallium was injected at 3 min after the start of ATP infusion. ATP was given at 0.12 mg/min/kg in two patients (group A), 0.16 mg/min/kg in three patients (group B), 0.20 mg/min/kg in one patient (group C) and 0.28 mg/min/kg in two patients (group D). SPECT images were obtained at 10 min and 180 min after thallium injection. No significant hemodynamic changes were observed in group A and B. Severe hypotension was observed in group C and one member of group D. Chest pain was experienced by one patient in group A, two in group B, one in group C, and both of the two in group D. ST depression on the electrocardiogram (ECG) was documented in one patient each of groups B and C. In one group D patient, the study was discontinued because of complete atrioventricular block persistent for 5 beats. The correlation between thallium imaging and CAG was unclear in group A, reasonable in groups B and C, and obscure in group D because of side effects. None of the patients who developed side effects of ATP were administered sublingual nitroglycerin or intravenous aminophylline. Their symptoms or ECG changes improved spontaneously within 2 min and disappeared within 5 min after termination of infusion. In conclusion, the optimal ATP regimen for this purpose was considered to be a 5 min infusion at 0.16 mg/kg/min and this method was found to be feasible and safe.

Adenosine Triphosphate↗
PubMed1990

Comparative evaluation on mouse nasal immunogenicity of arylmethane-, xanthene-, quinone-imine-, and acridine-dye-inactivated Sendai virus vaccines.

Twenty-seven kinds of organic dye-inactivated Sendai virus vaccines were prepared by treatment in dark at 23 C for 2 months or more, and selected with the high HA titers as a guide. Their nasal immunogenicities were examined in mice by contact infection and immunofluorescent method, and the relative merits of the dye-inactivants were determined. The strongest protection was elicited with acriflavine-, auramine O-, eosin Y-, neutral red-, night blue-, patent blue V-, thymol blue-, uranin-, and xylene cyanol FF-treated vaccines. Middling protective efficacy was induced by use of erio green B-, malachite green-, methyl green-, proflavine-, pyronin B-, and thionin-inactivated vaccines. Dye-inactivated vaccines that resulted in the weakest protection were Bindschedler's green-, bromothymol blue-, erythrosin B-, ethyl violet-, gallein-, light green SF yellowish-, methyl violet-, new methylene blue N-, phenol red-, rhodamine 6G-, spirit blue- and victoria blue B-treated ones. Serum HI titers developed by nasal vaccination were variable, and rose still more in most vaccinated groups postexposure. Elicitation of the most effective nasal immunogenicity in dye-inactivated vaccines appeared to depend on selective modification of capsid protein or ribose in viral core with dyes possessing definite functions, despite the different molecular structures.

Animals↗
PubMed1990

Dose-dependent transplacental infection of murine encephalomyelitis virus GDVII in gravid uterus.

Intrauterine infection of murine encephalomyelitis virus GDVII was investigated by the indirect immunofluorescence method. Sixty-day-old pregnant mice were inoculated with 5 gradated doses of the virus ranging from 0.001 to 1.5 MLD50 via i.v. route on the 10th day of gestation. The mice exsanguinated on postinfection day 8 showed high incidences of viral antigen in the uterine walls, placentas, and fetal subcutaneous tissues with doses of 0.1-1.5 MLD50, regardless of the presence of maternal symptoms. Incidence of viral antigen-positive cells in fetal brains was high with a dose of 0.1 MLD50, but not by the other doses. However, the brains of the stillborn and newly-born mice derived from females infected by a dose of 0.5 MLD50 brought about still higher detection rates of viral antigen, as well as in the postpartum uteri. In effect, transplacental transmission of the virus was clearly demonstrated, and appeared to be dose-dependent.

Animals↗
PubMed1990

Heat production as a quantitative parameter for cell differentiation and cell function.

Heat production was measured in relation to cell differentiation and phagocytie function using cells of human monocyte-histiocyte cell line U937. U937 cells differentiated monocytic phagocytes when cultured with lymphokine. Heat production increased as result of differentiation and phagocytosis. An important finding was that the heat increase in differentiated cells and during phagocytosis was directly proportional to the concentration of lymphokine. This strongly suggested that heat production is a quantitative parameter not only for cell differentiation but also for phagocytic function. The measurement of heat produced by mammalian cells can therefore be used to quantitate the differentiation and function of cells.

Body Temperature Regulation↗
PubMed1990

Heat production due to intracellular killing activity.

Using Saccharomyces ceravisiae, Candida albicans and Stapylococcus aureus, heat production during phagocytosis was measured in U937 cells which are capable of differentiating to monocytic phagocytes. No increase in heat production of non-differentiated U937 was observed since they were not phagocytic cells. However after differentiation to monocytic phagocytes by lymphokine, U937 cells produced a remarkable amount of heat during phagocytosis. Although Ehrlich ascites tumor cells sensitized with antibody were capable of engulfing S. aureus, no increase in heat nor in superoxide anion production during phagocytosis was detected. It was also found that no heat increase occurred in neutrophils from a patient with chronic granulomatous disease (CGD). It can thus be concluded that the heat production during phagocytosis is due to the intercellular killing process of phagocytic cells.

Animals↗
PubMed1979

[Scintigraphy].

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Arterial Occlusive Diseases↗
PubMed1978

67Ga-citrate scanning in hypernephroma.

67Ga scanning was performed in 26 patients with hypernephroma (17 with only a primary lesion of hypernephroma, 4 with both primary and metastatic lesions, 2 with hypernephroma and pyelonephritis, and 3 with only a metastatic lesion after nephrectomy). In patients with primary lesions alone, the positive finding rate by 67Ga scanning was low (26%), and in metastatic lesions that by scanning was high (86%). The practical conclusions are as follows: 67Ga scanning is of littel use as a diagnostic aid in primary lesion of hypernephroma, but may be useful in case with metastases with inflammatory disease.

Adenocarcinoma↗
PubMed1978

Clinical evaluation of tumor imaging with 201 TI chloride.

201TI was used as an imaging agent in 173 malignant tumors and 76 benign lesions. The sensitivity, specificity, and accuracy were 0.64, 0.61, and 0.63, respectively. Sensitivity was good in thyroid cancer (0.91) and fair in primary lung cancer (0.70) and primary liver cancer (0.71). Compared with 67Ga, 201TI appears to have a higher sensitivity in thyroid cancer and nearly the same sensitivity in primary lung cancer. 201TI might be useful in distinguishing cold thyroid nodules and in differentiating primary liver cancer from metastases.

Aged↗