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Biomedical subjects

I Fujisawa

Publications and source records attributed to I Fujisawa.

At least 37 records · Page 2Linked to original sources
PubMed1989

Post-transcriptional allelic exclusion of two functionally rearranged T cell receptor alpha genes.

We cloned and sequenced T cell receptor (TCR) alpha and beta chain cDNA from a lambda gt10 library obtained from a murine I-Ak autoreactive helper T cell clone MS202. Two types of cDNA clones for the alpha chain and one for the beta chain were obtained. The two alpha chain transcripts used two different V alpha genes: V alpha 4, joined to J alpha 11.2; and V alpha 5, J alpha TA13. The four V alpha 4 cDNA clones obtained did not have a complete sequences, lacking the leader portion. The V alpha 4 genomic gene segment of MS202 was revealed to contain two exons corresponding to the V alpha 4.MD13 cDNA sequence, and the potential RNA splicing signals between the two exons were intact. Both of the alpha chain cDNA clones showed in-frame rearrangements. Immunoprecipitation of 125I-surface-labeled lysate of MS202 with anti-TCR antiserum and subsequent electrophonetic analyses indicated that only one of the alpha chain polypeptides was expressed on the cell surface. Thus, allelic exclusion of the alpha chain in MS202 is achieved by post-transcriptional regulation rather than rearrangements.

Alleles↗
PubMed1989

Primary intrasellar microgerminoma detected by magnetic resonance imaging: case report.

A case of primary intrasellar germinoma in a 24-year-old woman is presented. Her initial symptoms were diabetes insipidus and headaches. The neurological examination found no abnormalities, but the endocrinological examination disclosed a deficiency in growth hormone secretion. Her skull x-ray revealed a normal sella turcica, and a computed tomographic scan revealed no abnormal mass in the pituitary fossa, but a slightly enlarged stalk. Magnetic resonance imaging revealed a small tumor in the posterior lobe. Transsphenoidal exploration revealed a germinoma in the posterior pituitary lobe. Six cases of primary intrasellar germinoma, including our case, were reviewed. Our case is considered to be the smallest intrasellar germinoma yet reported.

Adult↗
PubMed1989

Modulation of immune response against tumor cells by the in vivo administration of an autoreactive Th clone.

The immunization of C3H mice with irradiated syngeneic MM48 tumor cells induced specific tumor-neutralizing cells (TNC). The TNC activity was mediated by the L3T4+, Ly-2- T cell population, and the generation of TNC coincided with the appearance of delayed-type hypersensitivity response against MM48 antigen. The administration of an auto-I-Ak reactive T helper cell clone MS202 to normal C3H mice resulted in the facilitation of growth of MM48 tumor due to the induction of T suppressor (Ts) cells. Splenic T cells from animals given this T cell clone inhibited the TNC activity of immunized mice resulting in the escape of MM48 from the TNC effect. The surface phenotype of the Ts cells was L3T4+, Ly-2-. The Ts cells induced by the clone MS202 were totally antigen-nonspecific, and were able to suppress both the effector and inductive processes of TNC. The results suggest the presence of a physiological MHC-restricted T cell circuit that regulates immune responses against the growing tumors.

Animals↗
PubMed1989

Ectopic posterior lobe of the pituitary gland and intractable nocturnal enuresis in a case with pituitary dwarfism.

An 11 5/12-year-old girl with pituitary dwarfism had intractable nocturnal enuresis. Magnetic resonance imaging revealed pituitary stalk transection and the formation of an ectopic posterior lobe. The results of responses to dehydration, infusion of hyperosmolar NaCl solution, and 1-desamino-8-D-arginine vasopressin showed that the nocturnal enuresis in the present case was due to a partial vasopressin deficiency. We suggest that the ectopic posterior lobe is one cause of nocturnal enuresis.

Child↗
PubMed1989

Carcinoma of the cervix: staging with MR imaging.

Demonstration and staging of carcinoma of the cervix with magnetic resonance (MR) imaging was evaluated prospectively in 67 patients with histologically proven lesions. Findings were correlated with surgical/pathologic results obtained within 2 weeks. MR imaging had an accuracy of 95% in demonstrating invasive disease (stage IB or higher). It was capable of depicting the location and extent of tumor invasion of cervical stroma and helped detect tumor beneath relatively normal epithelium or within the endocervical canal that had not been detected by means of colposcopic biopsy. The overall accuracy of MR imaging in staging carcinoma of the cervix was 76%, and in demonstrating parametrial status, the overall accuracy was 89%. In 39 patients with proven invasive disease, the accuracy in demonstrating parametrial status was 82%. In 13 of these 39 patients the low-signal-intensity stromal ring of the cervix on MR images was completely preserved and there were no false-positive results. MR imaging is a highly promising method for directly demonstrating and staging carcinoma of the cervix and seems to be capable of providing answers to crucial questions regarding mode of therapy.

Adult↗
PubMed1989

Enlarged uterus: differentiation between adenomyosis and leiomyoma with MR imaging.

The potential of magnetic resonance (MR) imaging in differentiation of adenomyosis from leiomyoma was evaluated in 93 patients who had a palpable enlarged uterus that was suspect for leiomyoma or adenomyosis. In all cases, MR images were correlated with surgical/pathologic findings. Pathologic findings showed that 71 enlarged uteri were due to leiomyoma, including one leiomyosarcoma, and 16 were due to adenomyosis. The other six patients were shown to have an enlarged uterus attributable to simultaneous involvement of both lesions. On T2-weighted images, adenomyosis appeared as an ill-defined, relatively homogeneous low-signal-intensity area embedded with sparse high-intensity spots. In contrast, leiomyomas were well-circumscribed masses with a spectrum of signal intensity. The cause of uterine enlargement was correctly diagnosed with MR images in 92 of the 93 cases. It is concluded that MR imaging is highly accurate in helping to distinguish between adenomyosis and leiomyoma in cases of enlarged uterus.

Adult↗
PubMed1989

Gamna-Gandy bodies of the spleen: evaluation with MR imaging.

The authors retrospectively evaluated magnetic resonance (MR) images obtained in 64 patients with portal hypertension. Multiple low-intensity nodules were noted within the spleen in eight patients. In all eight cases, these nodules were most apparent on images obtained with the GRASS (gradient-recalled acquisition in the steady state) technique, which is known to be more sensitive to heterogeneity of the magnetic susceptibility, usually caused by hemosiderin deposition. In one of these cases, ultrasonography demonstrated diffuse hyperechoic spots that had been reported to represent Gamna-Gandy bodies of the spleen (ie, organized hemorrhage caused by portal hypertension). Although there was no pathologic proof in their series, the authors believe these low-intensity nodules seen on MR images may represent the hemosiderin deposits of Gamna-Gandy bodies.

Adult↗
PubMed1989

[Magnetic resonance imaging of the thorax].

We examined thirty-five patients with various chest diseases with cardiac gated Magnetic Resonance Imaging (MRI) at 1.5 tesla. Major advantages of MRI of the thorax are its abilities to display sagittal and coronal planes and to disclose vessels clearly without contrast media. We conclude MRI is useful in evaluating, 1) masses at the lung apex or base, 2) chest wall invasion, 3) hilar and mediastinal lymphadenopathy, 4) aortic aneurysm, and 5) bronchogenic cyst.

Adult↗
PubMed1988

Analysis of two distinct B cell activation pathways mediated by a monoclonal T helper cell. II. T helper cell secretion of interleukin 4 selectively inhibits antigen-specific B cell activation by cognate, but not noncognate, interactions with T cells.

A single monoclonal T helper (Th) clone can activate B cells in two distinct pathways; a cognate pathway requiring a major histocompatibility complex (MHC)-restricted T-B cell interaction, and a noncognate pathway not requiring an MHC-restricted T-B cell interaction. The present study was undertaken to investigate whether Th cells mediating a given immune response provide further regulatory function to B cells other than helper function. It was demonstrated that conditions of high antigen concentration which activate a noncognate B cell activation pathway simultaneously inhibit IgG responses. The inhibition is shown to be mediated by the T cell factor interleukin 4, produced by activated cloned Th cells. The inhibitory effect of this factor is directed to B cells and is MHC-unrestricted, antigen-nonspecific, and IgG class-specific. In addition to being susceptible to the effects of augmenting cells and suppressor cells, cloned Th cell populations can therefore themselves function as regulatory cells to inhibit IgG responses when stimulated with high dose of specific antigen. These results indicate that Th cells function to regulate B cells both positively and negatively, depending upon the activation conditions.

Animals↗
PubMed1988

Epitopes associated with major histocompatibility complex (MHC) restriction site of T cells. IV. I-J epitopes on MHC-restricted cloned T cells.

We studied the expression of an I-Jk epitope on class II-restricted cloned L3T4+ T cells established from H-2k, H-2b, F1 and semiallogeneic radiation bone marrow chimeras by the inhibition of antigen-induced T cell proliferation and in vitro secondary antibody response, and by the direct immunofluorescence with a monoclonal anti-I-Jk. Both I-Ak- and I-Ek-restricted T cells were shown to carry the identical I-Jk epitope regardless of their genotypic origins, antigen specificity, and helper or suppressor function. None of the I-Ab-restricted clones derived from similar animals showed the I-Jk epitope. This isomorphism, regardless of the restriction specificity for I-Ak or I-Ek, contradicts the idea that I-J is an idiotypic determinant on class II-restricted T cell antigen receptor (TcR). In fact, the I-Jk epitope was not comodulated with TcR/T3 complex when incubated with an anti-T3 antibody, indicating that I-J is a new isomorphic receptor for self different from TcR alpha/beta heterodimers.

Animals↗
PubMed1988

Adenomyosis: diagnosis with MR imaging.

Magnetic resonance (MR) imaging characteristics of adenomyosis were studied in eight women (aged 37-49 years) who underwent hysterectomy, and detailed radiologic/pathologic correlation was conducted in all cases. Adenomyosis produced diffuse and smooth uterine enlargement. The extent of the lesion was clearly identified on images obtained with long repetition time and long echo time; a diffuse, low-intensity area accompanied by tiny high-intensity spots was seen subjacent to the endometrium. The area appeared as a localized or diffuse thickening of the junctional zone because it was often isointense with this zone. Pathologic examination confirmed that the extent of adenomyosis correlated well with the low-intensity region on MR images and that both hemorrhagic areas and nonbleeding endometrial tissue corresponded to the high-intensity spots. The lesion consisted of distorted and compacted smooth muscle cells, but microscopic studies failed to explain the definitive difference in intensity between areas of adenomyosis and myometrium.

Adult↗
PubMed1988

Hemochromatosis of the pituitary gland: MR imaging.

Magnetic resonance imaging of the pituitary gland in a patient with secondary hemochromatosis is described. On T1-weighted images, the anterior lobe had almost no signal intensity, and only the high-signal posterior lobe was seen. These findings are compatible with the distribution of iron deposition and clinical symptoms in hemochromatosis.

Adult↗
PubMed1988

Thyroid masses: MR imaging and pathologic correlation.

The authors explored the capability of high-field-strength surface coil magnetic resonance (MR) imaging in disclosing the gross pathologic characteristics of thyroid masses (especially pseudocapsular and hemorrhagic degeneration). Twenty-four patients were examined, including 12 with papillary carcinoma, eight with adenoma, and four with adenomatous goiter. All patients underwent surgery within 2 days after MR imaging. Specimens were cut and correlated directly with MR images. The appearance of the pseudocapsule was classified into four types: A, intact and even thickness around the tumor; B, only partially present or even absent; C, intact but with uneven thickness; D, partially destroyed by tumor. MR imaging findings corresponded precisely with those of gross pathologic examination in all cases but four of adenoma. Type A pseudocapsules were found only in adenoma and type D only in papillary carcinoma. Although the number of cases in the series was limited, the authors conclude that MR images reflect gross pathologic findings well and that some characteristic findings are suggestive of benign or malignant disease.

Adenoma↗
PubMed1988

Spinal arteriovenous malformation: MR imaging.

Ten patients with spinal arteriovenous malformations (AVMs) were examined with high-field-strength (1.5-T) magnetic resonance (MR) imaging and a surface coil (eight patients) or head coil (two patients). Four AVMs were intramedullary, and six were extramedullary. There was one case of Foix-Alajouanine disease (subacute necrotizing myelitis; thrombosed AVM). Three important pathologic findings--myelomalacia, total thrombosis, and wall thickening of the draining vein--were clearly demonstrated at MR imaging and confirmed at autopsy. A flow-sensitive sequence was valuable in the depiction of one intramedullary AVM as hyperintense, the postoperative evaluation of AVM, and the differentiation of nidus from old intramedullary hematoma. In other AVMs, cord edema, periradicular hematoma, and reversible changes of cord scalloping after surgery were demonstrated. MR imaging demonstrated various pathologic changes of the spinal cord that could not be detected with any other imaging method.

Adult↗
PubMed1988

Hypothalamic-pituitary function in growth hormone-deficient patients with pituitary stalk transection.

We compared 1.5 T magnetic resonance (MR) image findings with hypothalamic-pituitary function in 11 patients with idiopathic pituitary dwarfism, each of whom had a history of perinatal abnormalities, and 1 patient with posttraumatic pituitary dwarfism. MR imaging revealed transection of the pituitary stalk in all patients and the formation of an ectopic posterior lobe at the proximal stump in 9 patients, none of whom had polydipsia or polyuria. Three patients without an ectopic posterior lobe had diabetes insipidus. The 5 patients who had small pituitary glands (less than 2 mm in height) had hypothyroidism with low serum TSH concentrations and low serum cortisol responses to insulin-induced hypoglycemia; however, 7 patients with normal-sized pituitary glands had normal thyroid and adrenal function. The serum GH response to GHRH did not correlate with the size of the pituitary gland. The patients with small pituitary glands had delayed or prolonged serum TSH responses to TRH and impaired serum LH and FSH responses to GnRH; 4 of the patients with normal-sized pituitary glands had normal serum TSH, LH, and FSH responses. Only 2 patients had high basal serum PRL concentrations. The endocrinological data suggest that reestablishment of the hypothalamo-hypophyseal portal circulation, which cannot be seen by MR imaging, may occur. We suggest that the primary cause of idiopathic pituitary dwarfism in many patients is injury to the pituitary stalk at birth.

Adolescent↗
PubMed1988

Tonsillar herniation on magnetic resonance imaging.

To evaluate the risk of tonsillar herniation, the caudal pole of the cerebellar tonsil in posterior fossa mass lesions and anomalies was investigated with magnetic resonance imaging. The cerebellar tonsil was clearly demonstrated in relation to the surrounding structures on T1-weighted images in the paramedian or midline sagittal plane. In 78% of a control group of 50 cases, the tonsil was located just on or close to the upper border of the posterior lip of the foramen magnum. It was close to the line of the foramen magnum in 4 cases (8%), but displacement below this line was not observed in any case. In 18 cases of posterior fossa mass lesions, the tonsil tended to be in a lower position than in the control group, and tonsillar displacement below the foramen magnum was noted in 3 cases. Two of these cases had anterior medullary displacement with loss of the cerebrospinal fluid (CSF) space anterior to the tonsil; these patients had either rapid clinical deterioration or severe papilledema. In the remaining case and in 3 additional cases of Chiari malformation, the tonsils were displaced into the cervical canal with preservation of the CSF space, and the patients showed no signs of rapid clinical deterioration or increased intracranial pressure. The present study suggests that tonsillar displacement through the foramen magnum with associated anterior medullary displacement and loss of the CSF space anterior to the tonsil can be regarded as a sign of tonsillar herniation.

Adolescent↗