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Biomedical subjects

M Iio

Publications and source records attributed to M Iio.

At least 379 records · Page 21Linked to original sources
PubMedDate not supplied

Early stage detection of chemotherapeutic effect on 203 GL glioma in mice as studied by P-31 NMR and flow cytometry.

The effect of chemotherapy against glioma in mouse was evaluated by 31P NMR spectroscopy and flow cytometry. We found that administration of ACNU or tegafur at a dose less than LD50 resulted in the partial suppression of the ratio of inorganic phosphate (Pi)/phosphocreatine (PCr) and phosphomonoester (PME)/creatine phosphate (PCr) after 24 or 48 hr, although these ratios are usually increased together with growth of tumors. Flow cytometric analysis of glioma in vivo showed an accumulation in cells containing tetraploid DNA by G2M block 24-48 hr after treatment. However, the change occurred at a period slightly later than that of the Pi/PCr ratio. In contrast, histological change was noted at eight days after administration. Hence, it is concluded that in vivo 31P NMR spectroscopy can detect a change in metabolic pathways in tumors as early as 24-48 hr after the administration of chemotherapeutic agents.

Animals↗
PubMedDate not supplied

Computer simulation of ventricular wall motion using the finite element method.

To investigate how changes in the mechanical characteristics of the myocardium caused by cardiac diseases affect ventricular wall motion, a new computer program to simulate wall motion using the finite element method has been developed. A simple two-dimensional finite element model of the left ventricle is designed with an idealized tension-length curve applied to each element. Pathological changes in the ischemic process are induced in a certain portion of the model to make it possible to evaluate the relationship between the type and degree of changes and abnormal ventricular wall motion (i.e., hypokinesis, akinesis, and dyskinesis). Assumption of plastic deformation at the affected site of the model reproduced the genesis of a ventricular aneurysm. The model is then transformed into a three-dimensional wire frame structure, and the results can viewed from any perspective. These simulations enable the semiquantitative comprehension of cardiac wall motion without need for complicated physiological experiments and may be applied to human cardiac motion in combination with data obtained from cardiac scintigraphy, echocardiography, ventriculography, or cine-CT.

Computer Simulation↗
PubMedDate not supplied

Measurements of magnetic relaxation times of normal tissue and renal cell carcinoma.

Spin-lattice (T1) and spin-spin (T2) magnetic relaxation times of 25 human renal cell carcinomas and their assorted normal tissues were measured with a Bruker NMR spectrometer operating at 20 MHz. The tissue samples were examined within four hours after surgery. The results (mean +/- SD) were as follows: renal cell carcinoma, T1 = 638 +/- 168 msec and T2 = 109 +/- 41 msec; normal renal tissue, T1 = 594 +/- 165 msec and T2 = 100 +/- 24 msec. These results indicate that there was no significant difference in T1 and T2 between normal renal tissue and carcinoma. Our results suggest that it is difficult to separate relaxation times of renal cancer from those of normal parenchyma and that the difference between T1 and T2 alone does not permit recognition of renal cell cancer. Paramagnetic contrast agents may be useful in MR imaging to differentiate renal cancer from normal parenchyma.

Adult↗
PubMedDate not supplied

Semiquantitative analysis of fatty liver using spectroscopic imaging by dephasing amplitude changing (SIDAC).

The potential utility of spectroscopic imaging by dephasing amplitude changing (SIDAC) was evaluated in fatty infiltration in rats induced by cholesterol and ethanol. There was an excellent correlation between the in vivo fat-to-water ratio obtained from SIDAC and that in liver specimens from in vitro measurement (r = 0.97). SIDAC is a promising method for semiquantitative analysis of fatty infiltration of the liver.

Animals↗
PubMedDate not supplied

An integrated radiotherapy treatment system and its clinical application.

A new total system for radiation therapy installed in our department consists of a linear accelerator unit with microcomputer-controlled multileaf collimators, along with a CT scanner installed in the same treatment room. Also included are a digitally controlled communal couch, a minicomputer, and a system of treatment planning devices. We have developed various kinds of external radiation treatment planning techniques (including dynamic ones) with this system on the basis of the concept of dose corresponding technique. A reference point setup method is needed to maintain a unified coordinate system through each step of the treatment procedure, and, as developed by us, permits a volume-oriented setup. This system has been evaluated for accuracy in a variety of clinical setups. A true three-dimensional dose calculation algorithm is required for treatment planning associated with multileaf collimator treatments in order to realize the potential accuracy of such a system.

Computer Simulation↗
PubMedDate not supplied

Clinical applications of Ga-67 DFO-DAS-fibrinogen.

Ga-67 DFO-DAS-fibrinogen scanning was performed in 15 patients to detect fresh arterial thrombus. Seven patients were preoperative cases of aortic aneurysm and eight were postoperative cases of graft bypass. Scanning was performed on the first and second days after the injection. Nine of 13 grafts in eight cases were visualized by 67Ga-DFO-DAS-fibrinogen scan. Velour Dacron grafts were more strongly visualized compared with woven Dacron or Goatex. In three patients with aortic aneurysm in whom fresh thrombus was identified by operative findings, arterial thrombus was clearly visualized by 67Ga-DFO-DAS-fibrinogen scan, whereas in three other patients with aortic aneurysm, thrombus was not visualized, although it was identified by other examinations. In one case, a marked accumulation was observed in the abdominal aorta, although no arterial thrombus was found at operation. This was thought to be an accumulation in a blood pool because it decreased on the second day. We think it important to observe the relative changes of accumulation.

Adult↗
PubMedDate not supplied

N-isopropyl I-123 p-iodoamphetamine brain scans with single photon emission computed tomography: mental sweating and EEG abnormality.

We studied a patient with hyperhidrosis and electroencephalographic (EEG) abnormality using N-isopropyl I-123 p-iodoamphetamine (I-123 IMP) with single photon emission computed tomography (SPECT). EEG abnormality was found predominantly in the frontal area, and sharp wave bursts were induced by hyperventilation. Ictal and nonictal scans were obtained with simultaneous EEG recordings. Ictal scans revealed increased uptake of IMP in the frontal cortex, reflecting hyperperfusion to the frontal area. The ratio of IMP uptake of the frontal to the parietal cortex (F/P ratio) was calculated both in the ictal and nonictal phase. In the ictal phase, the F/P ratio was 1.23, compared with 0.91 in the nonictal phase. The data indicated altered regional cerebral blood flow with EEG abnormality and hyperventilation load. Although the relationship between sweating and cortical function is not fully understood, our study indicates that excessive mental sweating is related to frontal cortical dysfunction. I-123 IMP-SPECT seems valuable for topographical demonstration of epileptogenic lesions and understanding the pathophysiological process of mental sweating.

Adult↗
PubMedDate not supplied

CT diagnosis of primary Budd-Chiari syndrome--membranous obstruction of the inferior vena cava.

Five cases with primary Budd-Chiari syndrome due to membranous obstruction of the hepatic segment of the inferior vena cava were examined by CT. In all cases, CT demonstrated caudate lobe enlargement, reticular low density within the liver parenchyma, splenomegaly, and collaterals via the ascending lumbar veins and azygous system. Pathological study revealed liver cirrhosis or fibrosis in all cases. In two cases, calcification was shown in the region of the hepatic segment of the inferior vena cava. Our results suggested that the CT appearance of primary Budd-Chiari syndrome was rather characteristic and useful in diagnosis, although membranous obliteration could not be shown directly on CT.

Adult↗
PubMedDate not supplied

MRI of callosal disconnection due to cerebral infarction.

Magnetic resonance imaging (MRI) was performed to study two cases of callosal disconnection due to cerebral infarction. Both cases had pure alexia and right homonymous hemianopsia. Midsagittal inversion recovery (IR) images demonstrated that the corpus callosum was completely intact, and coronal IR images revealed involvement of the lingual gyrus, fusiform gyrus, forceps major, inferior longitudinal fascicle, and optic radiation in the dominant cerebral hemisphere in both cases. Midline sagittal images provided direct visualization of the corpus callosum but did not provide sufficient information for the study of callosal disconnection syndromes. Coronal reconstructions aided in visualizing the relationship of lesions to the adjacent structures of cerebral white and gray matter. MRI may be one of the most useful tools for understanding the process of interhemispheric transference of information.

Aged↗
PubMedDate not supplied

Traumatic occlusion of renal artery: CT and angiography.

Four cases of traumatic renal artery occlusion are reported. A direct blow to the abdomen was considered to have caused renal artery occlusion in two cases. They were severely injured and had macroscopic hematuria. Aortography revealed an abrupt cut-off type of obstruction of the renal artery. In the other two, a rapid decelerating-type of injury resulted in damage to the intima of the renal artery. They showed almost no outward signs of injury and no macroscopic hematuria. Aortography disclosed a tapered occlusion of the renal artery. CT showed the rim sign between the seventh day and sixth week before the compromised kidney became apparent. It had disappeared by the time follow-up CT revealed contraction. One patient developed hypertension, which subsided after nephrectomy. CT findings of the patient suggested the possibility of predicting hypertension as a sequelae of acute renal artery occlusion.

Adolescent↗
PubMedDate not supplied

Intraarterial digital subtraction arteriography in the diagnosis and treatment of hepatic tumors.

Intraarterial digital subtraction arteriography (IADSA) was performed in 94 patients with hepatic tumors and evaluated on the following subjects: 1) visualization of small arteries in arterial phase, compared with film study, 2) visualization of faint tumor stains in hepatogram phase, compared with film study, 3) visualization of portal venous branches by intraarterial digital subtraction portography (IADSP). Interventional angiography was performed in 76 patients. Contrast dose and injection rate of IADSA was approximately a third of film study without dilution. The position of the catheter was identical in IADSA and film study. IADSPs were performed with 15-20 ml of 76% Urografin, which was injected into the superior mesenteric artery at the rate of 5 ml/sec after infusion of prostaglandin E1. Comparison in arterial phase of 67 patients showed 24 (36%) IADSAs were equal to film study. Thirty-nine (58%) were inferior but adequate for the diagnosis of hepatic tumors. Comparison in hepatogram phase showed 24 (38%) IADSAs were superior to film study and all were satisfactory for the diagnostic purposes. Ninety-eight percent of 86 IADSPs gave information about the patency of the main portal vein. Fifty-five percent of IADSPs opacified third-order portal vein branches or further. IADSA of hepatic tumors not only save time and contrast dose but was also satisfactory in image quality for interventional angiography.

Adult↗
PubMedDate not supplied

Localization of therapeutic gelatin emboli using radiolabeling--an experimental study.

Transcatheter embolization has recently gained widespread acceptance in the treatment of a variety of conditions. To clarify the localization of therapeutic gelatin particles, we have described a simple and safe technique of labeling gelatin particles with 99mTc using stannous chloride solution. This technique provides satisfactory labeling efficiency and allows excellent scintigraphic images of therapeutic gelatin emboli, thus making it possible to clarify the localization of the injected embolic material in vivo.

Animals↗
PubMedDate not supplied

Incidentally discovered small renal carcinoma: CT and angiography.

CT and angiographic features of nine incidentally discovered small renal adenocarcinomas are reviewed. They were all discovered by CT or US during screening procedures or examinations targeting the liver or pancreas. In our institute, they constituted 56 percent of renal adenocarcinomas whose diameters were 4 cm or less. CT without contrast enhancement detected abnormality in seven of the nine, but two were negative or equivocal. Postcontrast CT delineated all tumors as relatively low-density areas, since the normal parenchyma of the kidney showed intense contrast enhancement. We believe that isodense or nearly isodense masses that show relatively low density after contrast are diagnostic of small solid renal tumors. Dynamic study with a bolus injection of contrast medium added information about the vascularity of the tumors. Angiography revealed hypervascularity in only four of the tumors. The rest were avascular or hypovascular. Four tumors that were avascular in the AP arteriographic view were shown to be hypovascular by a tailored oblique view in which adequate obliquity of the angiographic projection was determined by referring to CT, so that the tumors would be seen in profile and would not be superimposed on by normal parenchyma or vertebral shadows.

Adenocarcinoma↗
PubMedDate not supplied

MRI of bone marrow.

MRI can visualize bone marrow more clearly than X-CT or RI because the bone generates weak signals whereas the fat in the marrow gives strong signals. We described diagnosis of various bone marrow disorders by MRI technique. Hyperplasia of bone marrow decreased fatty cells and resulted in prolongation of T1, whereas hypoplasia of bone marrow replaced hematopoietic cells with fatty cells and resulted in shortening of T1. In aplastic anemia, the localized hyperplastic areas in abnormal fatty marrow can be visualized. In bone tumor and metastasis to bone marrow, T1-weighted IR image can provide the best contrast between the tumor and normal marrow, although neoplastic and inflammatory lesions can not be differentiated by MRI. In iron storage diseases, MRI can detect early changes by its higher sensitivity to iron than that of X-CT. MRI may be usefull in monitoring bone marrow damages noninvasively to patients under radiation and/or anticancer drug therapy.

Adolescent↗
PubMedDate not supplied

MRI of brain infarction.

MRI of twenty patients with cerebral infarction were reported with their X-CT. MRI with long SE mode clearly showed the ischemic lesion at 18 hours after insult, whereas X-CT performed immediately after MRI scanning showed no abnormality. The signal contrast of the lesion with long SE mode seemed to increase slightly during the patient's course, for a period of several months. The MRI images with long SE at the chronic stage were varied: small lesions appeared as hot areas, whereas large lesions appeared as cold areas and were accompanied with signal enhancement in the surrounding areas. A phantom study was also performed and it was determined that MRI was superior to X-CT in its ability to detect tissue water. One of the reasons for the high diagnostic capability of MRI for acute stroke was, therefore, attributed to this experimental result.

Aged↗