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Biomedical subjects

Y Itai

Publications and source records attributed to Y Itai.

At least 163 records · Page 9Linked to original sources
PubMed1995

[Whole abdominal irradiation for peritoneal dissemination of alimentary tract cancers].

Between January 1986 and August 1991, 19 patients with alimentary tract cancers complicated by peritoneal dissemination received whole abdominal irradiation combined with intraperitoneal chemotherapy postoperatively. Using a moving-strip technique of irradiation, 12.0 Gy was delivered in three fractions to the entire abdominal contents with partial liver and kidney shielding. The primary tumor sites were the stomach in 12 patients, the colorectum in five, and the gall bladder in two. Nine patients with gross residual disease also received a limited field boost of 30.6 Gy in 17 fractions after completion of treatment to the whole abdomen. None of the patients failed to complete the planned dose despite acute gastrointestinal toxicity (nausea and vomiting, 84%, diarrhea and cramping, 78%) and acute hematologic toxicity (leukocytopenia, 84%, thrombocytopenia, 68%). Our follow-up study revealed that the actuarial one-year survival rate was 28.4% and the median survival time was 9.0 months. Survival rates at one-year for patients with colorectal and gastric cancer were 75.0% and 16.7%, respectively. Patients with gastric cancer (n = 12) had a poorer outcome than those with colorectal cancer (n = 5) in the present study. One reason for this difference may have been the presence of cancerous pleuritis, which was frequently observed in patients with gastric cancer. Therefore, more intensive treatment to prevent cancerous pleuritis seems to be necessary to improve the efficacy of whole abdominal irradiation.

Abdomen↗
PubMed1994

[Usefulness of superparamagnetic iron oxide particle (AMI-25) enhanced MR imaging for the diagnosis of liver tumors: comparison with contrast enhanced CT].

The purpose of this study was to clarify the usefulness of SPIO-enhanced MRI in the diagnosis of liver tumors in comparison with contrast-enhanced CT. The subjects were forty patients with 154 nodules in the liver. We compared SPIO-enhanced MRI with contrast-enhanced CT in terms of tumor-liver contrast and detectability of liver tumors. In terms of tumor liver contrast, SPIO-enhanced MRI was equal or superior to contrast-enhanced CT in 82% of cases. In the detectability of liver tumor, SPIO-enhanced MRI detected more tumors than contrast-enhanced CT, especially small tumors. Tumors undetected by SPIO-enhanced MRI that were detected by contrast-enhanced CT and/or plain MRI were adenomatous hyperplasia and inflammatory pseudotumor according to fine needle biopsy. There were no severe complications of SPIO-enhanced MRI. In conclusion, SPIO-enhanced MRI will be more useful than contrast-enhanced CT in the diagnosis of liver tumors. SPIO-enhanced MRI may be a promising diagnostic method for the detection of hepatic tumors, especially small ones.

Adult↗
PubMed1994

[Spiral volumetric CT: detection and characterization of small hepatic cavernous hemangioma].

Twelve patients with 25 hepatic cavernous "hemangiomas of less than 2 cm in diameter received spiral volumetric CT (SVCT) examination using the special scanning programs named "double-phase return scan" or "triple-phase scan", which referred to arterial-, portal-dominant and/or late phases. Twenty-three lesions were not only detected, but characterized by applying these programs, although it has been difficult to detect such smaller lesions with the single level dynamic CT because of respiratory misregistration or multi-spreading lesions. SVCT made it possible to scan the whole liver during single breath-hold without any misregistrations. SVCT should become an indispensable procedure to assess subcentimeter lesions in the liver.

Aged↗
PubMed1994

[Distribution and frequency of gastric cancer at the para-cardiac region and fornix].

To clarify the distribution and frequency of gastric cancer in the upper third of the stomach, especially in the para-cardiac region and fornix, we reviewed 634 lesions of all gastric cancers in any location in the University Hospital of Tsukuba University from April 1985 to March 1992. The para-cardiac region was defined as a circular area of 6 cm in diameter around the cardia. We found 56 lesions (8.8%) in the para-cardiac region, almost all of which were concentrated in the distal half of the para-cardiac region, and only three of which (0.47%) were in the fornix. Cancer in the upper third of the stomach tended to occur predominantly in aged male patients, and histologically most of them were classified as having differentiated adenocarcinoma. Since the percentage of advanced cancer at the para-cardiac region was much higher than at any other location, we should be careful to obtain double-contrast images of sufficient quality during the upper gastrointestinal examinations and not to overlook subtle changes in this region during the interpretation of films.

Adenocarcinoma↗
PubMed1994

In vivo human myocardial metabolism during aerobic exercise by phosphorus-31 nuclear magnetic resonance spectroscopy.

A few studies have been made in vivo on human myocardial energy metabolism. Hence, no discussion has taken place on metabolism during exercise or of training effects on metabolism. We examined human myocardial energy metabolism at rest and during exercise, and also training effects on the metabolism by phosphorus-31 nuclear magnetic resonance (31P NMR)-spectroscopy. Six sedentary male students (Cont) and six male long distance runners (Tr) were the subjects. Energy metabolism data were obtained from myocardium during rest and exercise by the region selection method using 31P NMR. Rotation of the legs while riding a bicycle, which was fitted with an ergometer we had made ourselves for NMR, imposed given exercise intensities. The heart rate was measured in a stationary phase during exercise. Although the heart rate at rest in the Tr group was significantly lower [Tr, 52.5 (SD 3.1) beat.min-1; Cont, 67.1 (SD 2.9) beat.min-1], no significant difference was observed in myocardial energy metabolism using the 31P NMR method [Tr, phosphocreatine/beta-adenosine 5'-triphosphate (PCr/beta-ATP); 1.51 (SD 0.02); Cont, 1.51 (SD 0.01)]. When NMR measurements were investigated at two different intensities of exercise, heart rates in the Cont group were significantly higher by about 20 beat.min-1 than those in the Tr group at both exercise intensities, while no difference in energy metabolism was observed between the groups or between rest and exercise [Tr, 75.9 (SD 3.6), 88.3 (SD 3.7) beat.min-1; PCr/beta-ATP 1.51 (SD 0.03), 1.51 (SD 0.03); Cont, 95.9 (SD 2.4), 115.1 (SD 3.5) beat.min-1, PCr/beta-ATP 1.51 (SD 0.01), 1.51 (SD 0.04)].(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1994

Muscle energetics in short-term training during hypoxia in elite combination skiers.

Four well-trained combination skiers were studied through pre- and post-training for the effects of short-term intermittent training during hypoxia on muscle energetics during submaximal exercise as measured by Phosphorus-31 nuclear magnetic resonance and maximal aerobic power (VO2max). The hypoxia and training in the cold was conducted in a hypobaric chamber and comprised 60-min aerobic exercise (at an intensity equivalent to the blood lactate threshold), using a cycle ergometer or a treadmill twice a day for 4, consecutive days at 5 degrees C, in conditions equivalent to an altitude of 2000 m (593 mm Hg). No change in VO2max was observed over the training period, while in the muscle energetics during submaximal exercise, the values of phosphocreatine/(phosphocreatine+inorganic phosphate) and intracellular pH were found to be significantly increased by training during hypoxia. During recovery, the time constant of phosphocreatine was found to have been significantly reduced [pre, 27.9 (SD 6.7) s; post, 22.5 (SD 4.7) s, P < 0.01]. The observed inhibition of phosphocreatine as well as that of intracellular pH changes after training during hypoxia and quicker recovery of phosphocreatine in submaximal exercise tests, may indicate improved oxidative capacity (i.e. a high adenosine 5'-triphosphate formation rate) despite the short-term hypoxia training.

Adult↗
PubMed1994

Changes in magnetic resonance images in human skeletal muscle after eccentric exercise.

To investigate the time-course of changes in transverse relaxation time (T2) and cross-sectional area (CSA) of the quadriceps muscle after a single session of eccentric exercise, magnetic resonance imaging was performed on six healthy male volunteers before and at 0, 7, 15, 20, 30 and 60 min and 12, 24, 36, 48, 72 and 168 h after exercise. Although there was almost no muscle soreness immediately after exercise, it started to increase 1 day after, peaking 1-2 days after the exercise (P < 0.01). Immediately after exercise, T2 increased significantly in the rectus femoris, vastus lateralis and intermedius muscles (P < 0.05) and decreased quickly continuing until 60 min after exercise. At and after the 12th h, a significant increase was perceived again in the T2 values of the vastus lateralis and intermedius muscles (P < 0.01) [maximum 9.3 (SEM 2.8)% and 10.9 (SEM 2.2)%, respectively]. The maximal values were exhibited at 24-36 h after exercise. In contrast, the rectus femoris muscle showed no delayed-stage increase. Also, in CSA, an increase after 12 h was observed in addition to the one immediately after exercise in the vastus lateralis, intermedius and medialis and quadriceps muscles as a whole (P < 0.01), reaching the maximal values at 12-24 h after exercise. The plasma creatine kinase activity remained unchanged up to 24 h after and then increased significantly 48 h after exercise (P < 0.05). Beginning 12 h after exercise, the subjects whose T2 and CSA increased less than the others displayed a faster decrease in muscle soreness.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Acute change of exercised muscle using magnetization transfer contrast MR imaging.

We evaluated the acute changes in exercised muscle using magnetization transfer contrast (MTC) MR imaging with a short repetition time sequence. Ten volunteers performed supine ankle dorsiflexion exercise. MTC gradient-recalled echo (GRE) images were obtained before and after exercise at 1.5 T. The effect of MTC was assessed by dividing the signal intensity on MTC GRE images by that on conventional GRE images (M(s)/M0). The signal intensity, M(s)/M0 and cross-sectional area of exercised muscle were all greater at 1-2 min after exercise than immediately after exercise. We propose that this additional increase in these parameters after exercise was due to physiological reflow or hyperemia. Since the M(s)/M0 showed a good correlation with free water content in exercised muscle, this ratio may provide a quantitative variable for evaluating dynamic change of water-macromolecule interaction in skeletal muscle.

Adipose Tissue↗
PubMed1994

Hepatic peribiliary cysts: multiple tiny cysts within the larger portal tract, hepatic hilum, or both.

PURPOSE: To describe characteristic imaging features of hepatic peribiliary cysts. MATERIALS AND METHODS: Four patients with hepatic cysts in which the radiologic (n = 3) or histologic (n = 1) findings were consistent with peribiliary cysts of the liver (multiple small cysts seen exclusively in the larger portal tract, hepatic hilum, or both at gross examination and dilatations of extramural peribiliary gland at histologic examination) underwent computed tomography (CT) and ultrasound (US). In three patients, CT was performed after drip infusion of cholangiographic contrast material. RESULTS: Contrast material-enhanced CT clearly depicted many tiny cysts along the larger portal veins up to the third- or fourth-order branch (n = 3). US depicted multiple cysts in the echogenic portal tract definitely (n = 2) or equivocally (n = 2). On cholangiographic contrast-enhanced CT scans, cystic areas were located adjacent to or surrounding the bile ducts, and the possibility of biliary dilatation, communication, or both was disproved. CONCLUSION: Hepatic peribiliary cysts can be diagnosed with US and enhanced CT, especially with CT performed after administration of cholangiographic contrast material.

Aged↗
PubMed1994

Tongue displacement: visualization with rapid tagged magnetization-prepared MR imaging.

The authors describe a technique to depict tongue muscle displacement with tagged magnetization-prepared gradient-recalled echo magnetic resonance imaging. Three Japanese volunteers (three men, aged 31-36 years) were studied while they articulated specific sounds. Each image was obtained in less than 2 seconds without need for gating. Displacement and alteration of the tags within the tongue muscle during phonation were clearly visible. The technique may prove useful in the study of phoniatric pathophysiology.

Adult↗
PubMed1994

Radiation tolerance of the liver in relation to the preserved functional capacity.

The radiation tolerance of the liver was investigated in 12 patients, 11 of them with liver cirrhosis, treated for hepatocellular carcinoma by partial liver irradiation with doses between 50 and 77 Gy. The tolerance was assessed by the complication probability (Lyman's model), which concerned the injured tissue itself, and by a prediction score used for postsurgical liver failure, which concerned the preserved functional capacity, assuming that the > or = 30 Gy volume was equivalent to the resected volume. The prediction score corresponded better with the observed risk of fatal liver failure than the complication probability. The liver volume after radiotherapy correlated largely with the untreated volume and the low-dose volume. Thus the preserved functional capacity gives a better expression of the radiation tolerance than direct measures of the extent of injured tissue.

Aged↗
PubMed1994

[Clinical assessment of 99mTc-MAG3 scintigraphy for impaired renal function].

The renal scintigraphy and clearance of 99mTc-mercaptoacetyltriglycine (MAG3) and 123I-ortho-iodohippuric acid (OIH) were compared in 12 patients with impaired renal function. The patients were first studied with MAG3 and then reinvestigated with OIH two days later. The MAG3 renal scintigraphy gave better quality and functional information in comparison with OIH. The MAG3 and OIH renogram showed identical relative kidney uptake and Tmax, but T1/2 of MAG3 was longer (p < 0.001). The plasma clearance of MAG3 was lower than that of OIH, but they correlated significantly (r = 0.87, p < 0.005). Also, the plasma clearances of MAG3 and para-aminohippuric acid (calculated by the standard clearance technique) showed good correlation (r = 0.77, p < 0.05). The urinary excretion during the first 60 min after injection was the same for the two radiopharmaceuticals. We conclude that 99mTc-MAG3 is a suitable alternative to 123I-OIH in renal scintigraphy.

Adolescent↗
PubMed1993

[The evaluation of lung cancers hidden by the mediastinal and hilar shadows on the plain chest film].

We retrospectively evaluated the plain chest frontal radiographs in four cases in which the lung cancers were quite difficult to observe prospectively on plain chest frontal radiographs in spite of the relatively large size of tumors (over 3 cm in diameter). Three of four cases were central-type lung cancers, two squamous cell carcinomas and one adenosquamous cell carcinoma. Since there was no associated atelectasis or obstructive pneumonia in these cases, wall thickening and indistinctness of the lumen of the central bronchi were the significant findings for diagnosis. One case proven to be adenocarcinoma was located in the periphery of S6. A focally increased radiopacity behind the descending pulmonary artery was the only finding to pointed out. Since tumors were not demonstrated directly in the aerated lungs, the condition of the central bronchi as well as the degree radiopacity of the pulmonary artery should be carefully interpreted.

Adenocarcinoma↗
PubMed1993

[Magnetization transfer contrast imaging of the skeletal muscle in gradient recalled echo sequence].

The human midcalf muscle images were obtained using gradient recalled echo (GRE) sequence with and without magnetization transfer contrast (MTC) sequence. A significant decrease of relative signal intensity was observed in muscle with off-resonance irradiation. The percentage increase of signal intensity after dorsiflexion exercises was 55.6% and 29.0% for MTC-GRE and GRE sequence, respectively. MTC technique might be useful in improving contrast between many tissues as well as muscles.

Adult↗