Search PubMed⌕ Search

Biomedical subjects

I Fujisawa

Publications and source records attributed to I Fujisawa.

At least 55 records · Page 3Linked to original sources
PubMed1987

MHC-restricted minimal regulatory circuit initiated by a class II-autoreactive T cell clone.

The in vivo administration of a self-class II-reactive Th clone MS202 derived from C3H into syngeneic mice resulted in the suppression of both primary and early secondary antibody responses against T cell-dependent antigens. The suppression was due to the generation of antigen-nonspecific Ts cells in the recipient, as the splenic T cells from the mice treated with MS202 were able to strongly suppress the in vitro secondary antibody response of primed syngeneic spleen cells. The dose-response curve of suppression indicated the generation of an effector type Ts that directly suppressed Th. The surface phenotype of Ts was Ly-1+,2-, L3T4+, I-J-. The presence of Ly-1+,2+ T cells was not required to induce the suppression. The suppression was strictly restricted to H-2k, as F1 Ts cells were able to suppress the response of C3H but not of B6 B cells helped by the same F1 Th cells. The experiments with chimeric mice indicated that the direct target of Ts is an MHC-restricted Th but not a B cell or APC. The results indicate the existence of a minimal regulatory circuit where an MHC-restricted Th induces a preprogrammed Ts that in turn directly suppresses Th with the same MHC-restriction specificity. The induction of and suppression by Ts appeared to be due to the direct recognition of MHC restriction sites of Th cells.

Animals↗
PubMed1987

Endometrial cysts of the ovary: MR imaging.

Magnetic resonance (MR) images of 15 cases of ovarian endometrial cyst were reviewed. With a high-field-strength (1.5-T) MR imager, T1- and T2-weighted images were obtained in axial and sagittal planes, with 5-mm section thickness. MR findings highly suggestive of an endometrial cyst included adhesions to the surrounding organs (e.g., loss of clear margin of the uterine body and tethered appearance of the rectum); a distinct low-intensity zone surrounding a cyst loculus on both T1- and T2-weighted images produced by a thick fibrous capsule; loculus contents with short T1 and long T2 values, attributed to hemorrhagic fluid; and prominent low intensity (shading) within a loculus on T2-weighted images, the mechanism of which is yet to be determined.

Adult↗
PubMed1987

Ovarian cystic teratomas: MR imaging.

Magnetic resonance (MR) imaging characteristics of ovarian cystic teratomas were evaluated in 18 patients with 23 surgically proved tumors. The fat within the tumor demonstrated characteristic intensity similar to that of subcutaneous fat and a pathognomic pattern of chemical shift artifact that helped differentiate ovarian cystic teratomas from endometrial cysts. In addition to fat, MR images of ovarian cystic teratomas had several other characteristics that allowed confident diagnosis, including gravity-dependent layering or floating debris, palm tree-like protrusions or rounded nodules (dermoid plugs), and, occasionally fat-fluid levels and globular calcification. MR images were diagnostic in 20 tumors and were able to depict a tumor measuring 2 cm in diameter. MR imaging appears to be valuable in problematic cases in which other modalities are not diagnostic.

Adolescent↗
PubMed1987

Vaginal agenesis: classification by MR imaging.

Vaginal agenesis was studied by magnetic resonance (MR) imaging lin a 15-year-old girl, a 19-year-old woman, and a 21-year-old woman. In each case MR studies demonstrated the presence or absence of a normal cervix and functioning endometrium. This information was useful in planning surgical management. MR imaging assisted in the classification of the abnormality by noninvasively demonstrating the details of pelvic anatomy-and the uterine morphologic characteristics.

Adolescent↗
PubMed1987

Hepatocellular carcinoma: MR imaging.

Sixty patients with hepatocellular carcinoma (HCC) were studied with computed tomography (CT) and magnetic resonance (MR) imaging at 1.5 T. MR imaging was equivalent to CT in detection of HCC. MR imaging was superior to CT in demonstrating the details of tumors, especially pseudocapsules. In 58 cases, main tumors were detected with MR imaging. On spin-echo (SE) 600/25 (repetition time msec/echo time msec) sequences, tumors were hyperintense in 18 cases, isointense in ten, and hypointense in 30. On SE 2,000/60 sequences, all but two tumors had high signal intensity. Pseudocapsules, intratumoral septa, daughter nodules, and tumor thrombi, which are important characteristics of HCC, were demonstrated in 22, three, six, and six cases, respectively, on MR imaging. MR imaging is useful for characterizing the internal architecture of HCC.

Adult↗
PubMed1987

Moyamoya disease: MR imaging.

Eleven patients with moyamoya disease were studied with magnetic resonance (MR) imaging performed with a high-field-strength (1.5-T) superconducting magnet. In all cases a fundamental pathologic change of moyamoya disease--occlusion or stenosis of the terminal portion of the internal carotid artery and the proximal portion of anterior and middle cerebral arteries--was clearly demonstrated. The characteristic collateral network from the suprasellar cistern to the basal ganglia, which corresponds to the "moyamoya vessels" on angiograms, was seen in several patients. Various ischemic changes, including infarction, brain atrophy, and ventricular dilatation, were also well demonstrated. MR imaging plays an important role in the diagnosis of moyamoya disease.

Adolescent↗
PubMed1987

Thyroid gland: MR imaging.

Magnetic resonance (MR) imaging was performed in eight healthy volunteers and 30 patients with histologically and endocrinologically proved thyroid diseases. The use of a surface coil greatly improved spatial resolution, and normal anatomic structures were well demonstrated. In thyroid tumors, the margin, pseudocapsule, and lymph nodes were easily detected. Smooth margins, lobulated margins, and pseudocapsules were found in both adenoma and papillary carcinoma, whereas unclear margins were found only in papillary carcinoma. An unclear margin between the tumor and adjacent normal thyroid tissue seemed to reflect an ill-defined tumor border on gross pathologic examination. Metastatic lymph nodes as small as 3 mm were seen. Identification of small vessels enabled detection of dilated vessels in thyroid parenchyma in patients with Graves disease. Hemorrhage (hemorrhagic degeneration) was often found in adenoma, papillary carcinoma, and adenomatous goiter, resulting in variable signal intensity.

Adenoma↗
PubMed1987

Metastatic nodules of hepatocellular carcinoma: detection with angiography, CT, and US.

Accurate detection of intrahepatic metastases, or daughter nodules, of primary hepatocellular carcinoma is of crucial importance. Due to the introduction of infusion hepatic angiography, computed tomography (CT) after Lipiodol (iodized oil) infusion, and intraoperative ultrasound (US), tumors less than 10 mm in diameter are now frequently found. We compared the diagnostic accuracy of these three modalities in the detection of nodules in 45 patients who had hepatocellular carcinoma (confirmed by biopsy). CT with Lipiodol was superior to hepatic angiography in demonstrating nodules when they were overlapped by the primary tumor or very small in size. Intraoperative US demonstrated nodules in four avascular or hypovascular hepatocellular carcinomas, which both hepatic angiography and CT failed to demonstrate. In cases associated with severe liver cirrhosis, differentiation of small nodules from regenerating cirrhotic nodules was sometimes difficult with intraoperative US. The combined use of these three modalities is indispensable for the accurate detection of small nodules of metastatic hepatocellular carcinoma.

Carcinoma, Hepatocellular↗
PubMed1987

Transection of the pituitary stalk: development of an ectopic posterior lobe assessed with MR imaging.

Magnetic resonance (MR) imaging was performed in ten patients with pituitary stalk transection who had idiopathic pituitary dwarfism. Contiguous sagittal T1-weighted images were obtained in all cases, and, in some, axial or coronal images were taken for further evaluation. On MR images, normal anterior and posterior lobes of the pituitary gland can be clearly differentiated because the posterior lobe has a characteristic high intensity on T1-weighted images. In the ten patients, the high-intensity posterior lobe was not seen, but a similar high signal intensity was observed at the proximal stump in seven patients. This high-intensity area is the newly formed ectopic posterior lobe, which secretes antidiuretic hormone just as the posterior lobe would. When the ectopic lobe completely compensates for the impaired posterior lobe, endocrinologic data indicate normal posterior lobe function. However, MR imaging can reveal the transection of the pituitary stalk and formation of the ectopic lobe.

Adolescent↗
PubMed1987

Direct radiographic magnification with computed radiography.

Computed radiography was combined with a 0.1-mm microfocus radiographic tube to obtain radiographic magnification of a x3 to x5. Gray-scale image processing compensated for the loss of radiographic contrast associated with the high-kilovoltage, short-exposure technique. The high-pass spatial frequency filtering capability of the computed radiography resulted in enhanced edges and increased displayed latitude. The improved image quality obtained by magnification computed radiography allowed delineation of subtle abnormalities and small anatomic structures not apparent on conventional screen-film contact or magnification radiographs.

Humans↗
PubMed1986

Stomach and duodenum: radiographic magnification using computed radiography (CR).

We performed direct radiographic magnification (X3) using a 0.1-mm microfocal tube and computed radiography (CR) in air-barium double-contrast studies of the stomach and duodenum. To eliminate blurring of the image due to motion, we used the maximum kilovolt peak rate possible (102 kVp), the maximum milliampere second rate possible (64 mAs), the shortest possible exposure time (0.1 second), and a horizontal x-ray beam. With the patients in the supine position, CR provided the wide image reproduction range required to obtain satisfactory radiographs. Image processing in the CR system produced radiographs with increased radiographic contrast and enhanced edge definition of anatomic borders or pathologic processes. The duodenal villi were clearly visible in 45% of the cases.

Computers↗
PubMed1986

Uterine cervical cancer: assessment with high-field MR imaging.

Nineteen patients with histologically proved cervical carcinoma were evaluated with magnetic resonance (MR) imaging. Clinical, MR, and surgical findings were compared to determine accuracy and clinical usefulness of MR in demonstrating mass and extent of disease. MR imaging enabled clear differentiation of corpus uteri, cervix, vagina, uterine ligaments, and tumor. Tumor was demonstrated as a high-intensity mass deforming the low-intensity cervix; the low background intensity of normal structures provided high contrast to the mass. MR imaging accurately demonstrated the tumor in all ten patients with locally advanced cervical carcinoma and showed a normal cervix in nine patients with early cancer. On sagittal images, the shape of corpus uteri, cervix, and vagina, and their relationship to the mass were clearly assessed, with their long axes usually in a single plane. On axial images, assessment of parametrial tumor extension was facilitated by clear definition of the low-intensity cervix and uterine ligaments. Although more study is needed to determine the accuracy of MR in staging, MR is a promising method in evaluating cervical carcinoma.

Adult↗