Search PubMed⌕ Search

Biomedical subjects

K Torizuka

Publications and source records attributed to K Torizuka.

At least 55 records · Page 3Linked to original sources
PubMed1991

[Clinical evaluation of 99mTc-hexakis 2-methoxy isobutyl isonitrile (MIBI): multicenter phase III clinical trial].

Multicenter Phase III clinical trial on a new myocardial imaging agent, 99mTc-hexakis 2-methoxy isobutyl isonitrile (99mTc-MIBI), was carried out in 464 patients with various cardiac disorders. Both planar and tomographic images provided high-quality regional myocardial perfusion images which correlated well with 201TlCl images. The positive ratios of myocardial infarction and angina pectoris by the agent were as high as that of 201TlCl. In addition, ventricular function and wall motion could be assessed with first-pass and ECG gated studies. There was no serious adverse reaction which were attributed to 99mTc-MIBI in any of patients studied. A transient metallic taste was observed immediately after the injection in approximately 64% of the patients. Based on its safety and efficacy, the clinical usefulness of 99mTc-MIBI was observed in 562 (93.1%) of 604 injections. In conclusion, 99mTc-MIBI was useful as a imaging agent of myocardial blood flow.

Adolescent↗
PubMed1991

[Phase I clinical study on 99mTc-MIBI].

A phase I clinical study on 99mTc-hexakis 2-methoxy isobutylisonitrile (99mTc-MIBI) was carried out in 6 normal volunteers. There was no significant change in vital signs and laboratory parameters attributing to the reagent other than complaint of slight and transient metallic taste immediately after the injection in 4 volunteers. The highest dosimetry was calculated as 1.1 mGy/37 MBq at lower large intestine, which was within the acceptable range. 99mTc-MIBI was rapidly cleared from the blood and accumulated in the heart immediately after the injection with 1.4% dose and 1.8% dose at 5 min at rest and at stress, respectively. The retention of radioactivity in the heart well continued for at least several hours. The heart-to-lung ratio was over 2.00 at 5 min and heart-to-liver ratio was over 1.00 at 60 min. Myocardial planar and SPECT images were obtained with high quality. In conclusion, 99mTc-MIBI is a useful myocardial perfusion imaging agent.

Adult↗
PubMed1991

[A Phase 1 study of beta-methyl-p-(123I)-iodophenyl-pentadecanoic acid (123I-BMIPP)].

Phase 1 study of beta-methyl-p-(123I)-iodophenylpentadecanoic acid (123I-BMIPP), a new radiopharmaceutical developed for the evaluation of myocardial fatty acid metabolism, was performed in six normal volunteers to evaluate its biodistribution and safety. After intravenous injection of 111 MBq of 123I-BMIPP, the agent accumulated to the myocardium rapidly (5.4 +/- 0.6% at 1.5 hr after injection) and was washed-out slowly (5.1 +/- 0.4% at 3.0hr). 123I-BMIPP demonstrated no significant accumulation to any specific organs other than myocardium, liver and muscle. Myocardium was clearly visualized in the planar and SPECT images obtained 30 min and 3 hrs after injection. The absorption doses from 123I-BMIPP estimated by MIRD method were lower than those from 201Tl in all organs. Neither adverse reactions nor abnormal clinical laboratory findings were found in the safety evaluation. These results suggest 123I-BMIPP is a promising agent for evaluating myocardial fatty acid metabolism.

Adult↗
PubMed1989

Glucose metabolism and rate constants in Alzheimer's disease examined with dynamic positron emission tomography scan.

Glucose metabolic rate constants in patients with Alzheimer's disease were analyzed using dynamic positron emission tomography with [18-F] fluoro-2-deoxyglucose (FDG). The cerebral metabolic rate of glucose (CMRG) was calculated using obtained rate constants, as well as the autoradiographic method. The half-life and distribution volume of FDG between the blood and the brain tissue were also calculated from obtained metabolic rate constants. The most severely affected metabolic step was the phosphorylation of glucose in the parietotemporal regions. The distribution volume of FDG showed no remarkable deviation from normal controls, while the half-life of FDG was found to be longer in the parietal and temporal regions. The CMRG from rate constants and that from the autoradiographic method showed no remarkable differences.

Alzheimer Disease↗
PubMed1989

Value of stress thallium-201 emission tomography for predicting improvement after coronary bypass grafting and assessing graft patency.

To examine the value of stress and redistribution thallium-201 single photon emission computed tomography (SPECT) for predicting improvement after coronary artery bypass grafting (CABG) and for assessing graft patency, 17 patients underwent SPECT before and after CABG. Preoperatively, 16 patients (94%) showed reversible ischemia with redistribution, and defect score decreased from 16.4 +/- 7.6 to 8.3 +/- 5.8 (p less than 0.001) on 2 hour delayed images. Stress electrocardiography was positive in 15 cases (88%). The stress defect score was reduced postoperatively (7.8 +/- 6.3) as compared to the preoperative score (16.4 +/- 7.6) (p less than 0.001). Postoperatively, 7 cases (41%) showed reversible ischemia and the defect score decreased from 11.3 +/- 6.5 to 6.1 +/- 4.7 (p less than 0.05), while 4 cases (23.5%) showed positive stress electrocardiograms (ECG). Resting left ventricular (LV) ejection fraction (EF) improved in 6 cases (48.3 +/- 5.4% preoperatively to 56.8 +/- 7.4% postoperatively, p less than 0.05) and showed a reduction in 11 (58.2 +/- 10.5% to 47.5 +/- 9.4%, p less than 0.01). Grafts were occluded in 6 cases, and redistribution was evident on the delayed thallium images in all cases (100%), while stress ECG was positive in only 3 (50%). Thus, stress and redistribution SPECT is valuable for identifying patients who will improve after surgery and assessing graft patency more accurately than stress ECG. Resting LVEF was less useful for assessing improvement in LV function.

Adult↗
PubMed1989

[Study on determination of the imaginary axis of the tooth crown in anterior teeth: 1].

1. The state of inclination and the change under various conditions of the imaginary axis of the tooth crown of upper jaw anterior teeth can be determined by the image measuring system and method of this study. 2. The measurement error of this system was not more than 0.3 degree. This value was sufficient for the purpose of this study. 3. The imaginary axis of the tooth crown of anterior teeth was determined on the study cast with 1 to 3 degrees in mesiodistal direction and 2 to 4 degrees in labiopalatal direction as standard deviation. 4. The imaginary axis of the tooth crown of anterior teeth was determined toward labial in the random position and toward patient's right and palatal in Standing Posture. 5. It was confirmed that the determination of the imaginary axis of tooth crown was effected by the position of the patient relative to the operator, limitation or direction of view, and approach direction.

Humans↗
PubMed1989

[Study on determination of the imaginary axis of the tooth crown. 1. Measuring procedure].

The state of inclination and the change under various conditions of the imaginary axis of the tooth crown of upper jaw and lower jaw right and left first molar can be determined by the measuring apparatus and method of this study. 2. The measurement error of this method was not more than 0.1 degree. This value was sufficient for the purpose of this study.

Molar↗
PubMed1988

Effect of AA861, a 5-lipoxygenase inhibitor, on amylase secretion from rat pancreatic acini.

We have examined the effects of 2,3,5-trimethyl-6-(12-hydroxy-5,10-dodecadiynyl)-1,4-benzoquinone (AA861), a selective inhibitor of 5-lipoxygenase, on the action of cholecystokinin (CCK) and other secretagogues in the stimulation of amylase secretion from dispersed rat pancreatic acini. AA861 inhibited amylase secretion caused by CCK, carbamylcholine (carbachol), bombesin or calcium ionophore A23187 but failed to affect amylase secretion by vasoactive intestinal peptide or 12-O-tetradecanoyl-phorbol 13-acetate. Inhibition by AA861 of CCK or carbachol-induced amylase secretion was confined to the relatively lower concentrations of these secretagogues. AA861 did not inhibit receptor binding of CCK or alter the cellular calcium mobilization induced by CCK. In kinetic studies, AA861 was effective only on amylase secretion from pancreatic acini incubated with CCK for more than 5 min. Indomethacin, a known inhibitor of cyclooxygenase, did not affect the amylase secretion caused by all secretagogues used. These results indicate that the 5-lipoxygenase pathway of arachidonate metabolism may be involved in the actions of calcium-dependent secretagogues of amylase secretion in rat dispersed pancreatic acini, especially for sustaining stimulation of amylase secretion by CCK.

Amylases↗
PubMed1988

A new method of measuring in vivo sound speed in the reflection mode.

This paper describes a new method for in vivo sound measurement in the reflection mode. The mean sound speed between the reflector and linear array transducer is measured using the following three parameters: time of flight, time of flight difference, and distance between two receiver elements. To detect time of flight, the system delay-line time compensator is adjusted to obtain the sharpest reflector image. This method was evaluated in vivo in human livers, specifically 26 normal, 27 cirrhotic, and 15 fatty livers. The mean sound speed between diaphragm and the transducer was obtained. The measured sound speed was significantly higher in cirrhotic livers and lower in fatty livers.

Fatty Liver↗
PubMed1988

Positive imaging of venous thrombi and thromboemboli with Ga-67 DFO-DAS-fibrinogen.

A newly developed thrombus imaging agent, 67Ga-DFO-DAS-fibrinogen (67Ga-fibrinogen), was used for 22 studies in 20 cases of suspected deep venous thrombosis. Increased accumulation of 67Ga-fibrinogen in venous thrombi was depicted at 48 h after injection in 10 of the 15 cases (10 of 17 studies) who showed abnormal findings in radionuclide venography. A hot spot in the lung emboli was visualized in two cases. Seven of the eight cases having anticoagulant therapy showed increased 67Ga-fibrinogen uptake, while follow-up 67Ga-fibrinogen scintigraphy after the administration of heparin and urokinase did not reveal an abnormal hot spot in one case. 67Ga-fibrinogen can be made available simply by adding 67Ga solution to a vial containing fibrinogen-DAS-DFO conjugate. In conclusion, 67Ga-fibrinogen is considered to be a promising agent for detecting active venous thrombi and to assess the effect of anticoagulant therapy.

Adult↗
PubMed1988

Measurement of arterial time-activity curve by monitoring continuously drawn arterial blood with an external detector: errors and corrections.

Accurate description of the arterial time-activity curve (ATAC) is of paramount importance in quantitative determination of the regional cerebral blood flow (rCBF) using positron tomography following bolus i.v. injection of 0-15 labeled water. Frequent manual sampling from an arterial catheter does not permit sampling in less than 5-sec intervals and runs the risk of missing the arrival time or the peak count. A continuous ATAC monitoring system has been developed. This system consists of a single bismuth germinate detector in a lead shield and a constant-flow aspirator. The arterial blood was drawn continuously from a catheter within the brachial artery into an extended tube and its activity was monitored by the detector as the detector time-activity curve (DTAC). Comparison with the manual sampling from the contralateral brachial artery in the same run revealed that the DTAC differed from the manual sampling not only in delayed arrival but also in the shape of the curve, which was dispersed because of viscosity and the width of the detector field of view. However, deconvolution of DTAC using the experimentally obtained system step response provided an accurate arterial time course, which successfully filled in the gaps of the manual sampling. Moreover, water and blood showed different dispersion in the step response, suggesting that the system function should be determined using blood or a fluid of similar hydrodynamic nature.

Arteries↗
PubMed1988

Scintigraphic evaluation of two cases with alveolar soft part sarcoma.

Two cases of alveolar soft part sarcoma were examined with gallium-67 citrate (67Ga), technetium-99m-methylenediphosphate (99mTc-MDP) and technetium-99m(V)-dimercaptosuccinic acid (Tc(V)-DMS) to compare the sensitivity of these three radiopharmaceuticals. All scintigrams were positive with primary tumor, and images with Tc(V)-DMS were the best. Skull metastasis could be also detected by all agents, but scintigrams with lung metastases were negative. In scintigraphic evaluation of alveolar soft part sarcoma, Tc(V)-DMS may be a better agent than 67Ga or 99mTc-MDP.

Adult↗