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Biomedical subjects

K Torizuka

Publications and source records attributed to K Torizuka.

At least 181 records · Page 10Linked to original sources
PubMed1985

Accumulation of Tc-99m methylene diphosphonate in calcified metastatic lesions of the liver from colonic carcinoma. Comparison with calcification on X-ray computed tomogram.

Abnormal accumulation of Tc-99m MDP in two metastatic lesions of the liver was observed in a patient with resected colon carcinoma. Single-photon emission computed tomography (SPECT) revealed characteristic marginal accumulation of Tc-99m MDP in both of those metastatic lesions. X-ray CT showed the corresponding marginal calcification in one of the metastases, but no apparent calcification was observed in the other lesion. Two months later, however, the latter also became calcified on x-ray CT. These findings suggest that the accumulation of Tc-99m MDP in the present case is strongly related to the calcium deposition and that Tc-99m MDP may accumulate in a calcified metastatic lesion before the calcification appears on x-ray CT.

Calcinosis↗
PubMed1985

Is ECT imaging with Tc(V)-99m dimercaptosuccinic acid useful to detect lung metastases of osteosarcoma?

ECT imaging, using Tc(V)-99m dimercaptosuccinic acid [Tc(V)-DMS] was performed in two patients with lung metastasis of osteosarcoma, and the results were compared with those of CT scan. Clear accumulation of Tc(V)-DMS was recognized in all cases in the same area that CT scans demonstrated. Tc(V)-DMS was labeled under optimal pH 8, had very low SnCl2 concentrations, an equilibrium between a stable form and a dissociated form of anion TcO4(3-) structurally similar to PO4(3-), and was postulated for tumor uptake. Considering this proposed mechanism for Tc(V)-DMS uptake by tumor cells, ECT imaging using this tracer could be of use in the early detection of lung metastasis of osteosarcoma.

Adolescent↗
PubMed1985

Thallium-201 myocardial perfusion imaging in myocarditis.

TI-201 myocardial perfusion imaging was performed in six patients with clinically documented myocarditis. Each case manifested electrocardiographic abnormalities with elevation of serum cardiac enzymes and no significant stenosis of the coronary arteries observed on angiogram. Resting TI-201 images were visually assessed by three observers. Focal perfusion defects were observed in three cases (50%), among which two showed multiple perfusion defects. Emission computed tomography using TI-201 clearly delineated multifocal lesions in the first case. On the other hand, no significant perfusion defects were noted in the remaining three cases. Thus, myocarditis should be considered as one of the disease entities that may produce perfusion defects on TI-201 myocardial imaging.

Adolescent↗
PubMed1985

Imaging of head and neck tumors with technetium(V)-99m DMSA. A new tumor-seeking agent.

Tumor scintigraphy, using Tc(V)-99m DMSA was performed on 76 patients with head and neck tumors. In 32 cases, SPECT also was performed. Tc(V)-99m DMSA was found to have a sensitivity of 75% (56 cases), a specificity of 85% (20 cases) and an accuracy of 78% on planar imaging. ECT studies showed accumulation of Tc(V)-99m DMSA in all 25 malignant cases studied. However, in benign tumors, four of seven cases (57%) showed radionuclide uptake. Tc(V)-99m DMSA has superior physical properties to Ga-67 and could be of use in the diagnosis of head and neck tumors.

Adult↗
PubMed1985

Identification of 1,24(R)-dihydroxyvitamin D3-like bone-resorbing lipid in a patient with cancer-associated hypercalcemia.

A lipid indistinguishable from 1,24(R)-dihydroxyvitamin D3 [1,24(R)-(OH)2D3] was found in serum and tumor extracts from a hypercalcemic patient with a small cell carcinoma of the lung. The lipid comigrated with authentic 1,24(R)-(OH)2D3 on high performance liquid chromatography using both straight and reverse phase columns and competed with tritiated 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3)] for binding to intestinal 1,25-(OH)2D3 receptor. Increasing doses of the lipid factor from tumor and authentic 1,24(R)-(OH)2D3 gave parallel responses in a bone resorption assay, as assessed by 45Ca release from prelabeled mouse calvaria. The lipid factor from the patient's serum and authentic 1,24(R)-(OH)2D3 had identical biological activities in the receptor binding and bone resorption assays. In addition, the mechanisms of action of this lipid factor and 1,24(R)-(OH)2D3 were indistinguishable. Bone resorption by both was inhibited by calcitonin, and neither the lipid factor nor authentic 1,24(R)-(OH)2D3 affected cAMP content in osteoblast-like bone cells derived from mouse calvaria. The estimated concentrations of the 1,24(R)-(OH)2D3-like lipid, expressed as 1,24(R)-(OH)2D3 were 11 ng/g tumor wet wt by the receptor binding assay and 9.2 ng/g tumor wet wt by the bone resorption assay. The mean serum concentration was 1.4 +/- 0.3 (+/- SD) ng/ml (n = 3) by the receptor binding assay. No activity was detected in either bioassay when extracts of nontumor tissues from this patient or tumor extracts and sera from one hypercalcemic and four normocalcemic cancer patients were tested. The mean serum 1,25-(OH)2D level was low (6.4 +/- 0.5 pg/ml; n = 2), and serum 1,24(R),25-(OH)3D in this patient was high (103 pg/ml) compared to normocalcemic cancer patients, in whom the mean serum 1,25-(OH)2D level was 27 +/- 12 pg/ml (n = 4) and the 1,24(R),25(OH)3D level was 28 +/- 1.3 pg/ml (n = 4). Thus, the 1,24(R)-(OH)2D3-like lipid may be a substrate for metabolic conversion to 1,24(R),25-(OH)3D in vivo. These results provide evidence for the presence of a novel metabolite of vitamin D3, 1,24(R)-(OH)2D3. Detection of this bone-resorbing lipid in both tumor and serum suggests, but does not prove, that the tumor secreted this bioactive lipid into the circulation and that the high level of circulating bone-resorbing lipid was related to the hypercalcemia in this patient.

Animals↗
PubMed1985

Left ventricular responses to supine bicycle exercise assessed by radionuclide angiocardiography and a Swan-Ganz catheter.

Left ventricular responses to supine bicycle ergometer exercise were studied by gated radionuclide angiocardiography (RNA), in 12 normal subjects (group A), 11 coronary patients without effort angina (group B) and 17 coronary patients with effort angina (group C). In the serial measurement of global ejection fraction (EF) there was a significant increase during peak exercise (PEx) in group A and B. In group C, global EF during mild exercise (MEx) did not increase, but decreased significantly during PEx. These results suggest the necessity of achieving adequate exercise loading in the diagnosis of exercise-induced ischemia, and also, that the serial measurement of global EF during exercise appears to be highly valuable. In the assessment of regional wall motion on the basis of regional EF, abnormal responses to exercise were highly inducible in the anteroseptal region in coronary patients with left anterior descending artery involvement. Abnormal wall motion in the other regions was less indicative for right coronary or left circumflex artery dysfunction. We examined hemodynamic responses to exercise by a Swan-Ganz catheter during RNA study in 5 patients of group A, 5 of group B, and 9 of group C. There was a large increase in left ventricular stroke work index (LVSWI) with a small rise in pulmonary capillary wedge pressure (PCWP) in group A. In group B LVSWI increased with a moderate rise in PCWP during PEx. In group C there was a negligible increase of LVSWI despite a marked rise in PCWP. A similar relationship was present between the LVSWI and the end-diastolic count (EDC) in the left ventricular region of interest. In MEx, however, the rise in PCWP in group C was more prominent than the increase in EDC. Thus, the present data indicate that the left ventricle in group C operates on a steeper portion of the diastolic pressure-volume curve than that in group A or B.

Adult↗
PubMed1985

Noninvasive evaluation of regional myocardial perfusion with positron emission computed tomography.

Positron emission computed tomography (PET) offers regional measurement of physiological and biochemical processes in vivo. We have constructed a whole-body multislice PET scanner, which provides 7 tomographic images at 16 mm intervals simultaneously. The high sensitivity with good spatial resolution of this system permits dynamic studies of the heart. PET scan of the heart was performed following intravenous bolus injection of 13N labeled ammonia. Serial dynamic images in normal cases showed early accumulation of tracer in the myocardium and rapid clearance from the cardiac blood pool. Delayed clearance from the blood and prolonged retention in the dorsal part of the lungs were observed in cases with myocardial infarction. A perfusion defect was clearly visualized in myocardial infarction except for infarction of the inferior wall. Transient ischemia was also visualized with exercise loading. Thus, PET with 13N ammonia is a valuable diagnostic tool for the evaluation of regional myocardial perfusion in coronary artery disease.

Ammonia↗
PubMed1985

Real-time sonography of palpable breast masses.

In order to evaluate the clinical usefulness of an electronic real-time linear array scanner in breast diseases, ultrasonography was performed in 148 cases of histologically confirmed palpable breast masses. The real-time images were observed on a television monitor while moving the hand-held transducer probes over the masses. It took only a few minutes to examine and diagnose a palpable mass. Among 45 carcinomas, 39 lesions were correctly diagnosed, four lesions were not detected by ultrasound and two were misdiagnosed as fibroadenomas. On the other hand, ten benign lesions were falsely diagnosed as breast cancers: seven mastopathies (including four sclerosing adenosis), two fibroadenomas and one abscess. The sensitivity and specificity for diagnosing breast cancer were 0.87 and 0.90 respectively. Real-time sonography is a simple, time-saving and useful tool for examining palpable breast masses. However, it should be realised that some breast cancers are difficult to image and differentiate from benign lesions.

Adenofibroma↗
PubMed1985

Effect of DTPA conjugation on the antigen binding activity and biodistribution of monoclonal antibodies against alpha-fetoprotein.

Indium-111-(111In) labeled monoclonal antibodies (Ab) prepared with a bifunctional chelating agent, diethylenetriaminepentaacetic acid (DTPA), have been used for the radioimmunoimaging of cancer. In the present experiment, using monoclonal Ab against human alpha-fetoprotein (AFP) as a model, we have studied the effect of DTPA conjugation on the antigen binding activity and the biodistribution in nude mice transplanted with AFP-producing human testicular tumor. In Ab heavily conjugated with DTPA, the Scatchard plot analysis demonstrated that the maximum binding capacity rather than the affinity constant was affected. Under selected conditions, 111In-labeled Ab were made available with almost full retention of the antigen binding activity and scintigrams of nude mice clearly delineated the site of the tumor. However, the number of DTPA molecules incorporated per Ab molecule markedly influenced the in vivo biodistribution as well as the in vitro antigen binding activity.

Animals↗
PubMed1985

Imaging of the hepatocellular carcinoma using dynamic positron emission tomography with nitrogen-13 ammonia.

Dynamic PET using [13N]ammonia was performed in patients with primary hepatocellular carcinoma (hepatoma). All the tumors started to show remarkable accumulation of radioactivity from a very early period (within 150 sec after the radionuclide injection), whereas the radionuclide was more gradually accumulated in the liver. Central necroses of the tumors were visualized as low radioactivity areas. Daughter nodules of less than 2 cm were also visualized. This dynamic PET study is a valuable technique for the detection of the hepatoma.

Ammonia↗
PubMed1985

[Sequential measurement of serum CA 125 levels in Krukenberg's tumor].

CA 125 is a tumor marker for ovarian cancer developed by hybridoma technology. In the present study, the levels of CA 125 were sequentially measured in the serum of five patients with Krukenberg's tumor originating in the gastrointestinal tract. Four out of the five (80%) had elevated serum CA 125 levels, i.e., greater than 35 U/ml and, in most cases, these levels decreased after resection of the ovarian tumor. Serum CA 19-9 and CEA levels were also increased in two (40%) and three (60%) patients, respectively, and, in these positive cases, reflected the clinical course. The results indicated the clinical usefulness of these cancer markers in Krukenberg's tumor.

Antigens, Neoplasm↗