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Biomedical subjects

K Ohtomo

Publications and source records attributed to K Ohtomo.

At least 127 records · Page 7Linked to original sources
PubMed1992

MR imaging of malignant mesenchymal tumors of the liver.

Magnetic resonance (MR) features of five primary malignant mesenchymal neoplasms (plasmocytoma, leiomyosarcoma, undifferentiated sarcoma, epithelioid hemangioendothelioma, and angiosarcoma) of the liver were reported. All tumors were hypointense on T1-weighted images and hyperintense on T2-weighted images. No halo and intravenous extension were noted. A target appearance was revealed in epithelioid hemangioendothelioma. MR findings of angiosarcoma were essentially the same as those of cavernous hemangiomas (markedly hyperintense with hypointense linear septa on T2-weighted images). MR findings of these rare hepatic malignancies were nonspecific, although they were quite different from those of typical hepatocellular carcinomas. This study suggested that MR differentiation of primary hepatic mesenchymal tumors from other common benign and malignant neoplasms was difficult; however, the number of studied cases was limited.

Adolescent↗
PubMed1992

Fractal dimension of dendritic tree of cerebellar Purkinje cell during onto- and phylogenetic development.

The cerebellar Purkinje cell has highly branched dendrites extending in a transverse plane to the cerebellar folium. Branching patterns of the dendrites were subjected to fractal analysis to obtain a quantitative measure of their intricacy. Using a square-covering method, we found that dendrites have a statistical self-similarity so that their fractal dimension can be evaluated. In postnatal mouse, dimensions of Golgi-stained Purkinje cells increased as dendrites developed. The time course of the dimension increase was correlated with development of the width and area of the dendritic fields. After the dimension reached the maximum value at postnatal day 20, the width and area further continued to grow until day 100. In human cerebellum, dimensions of Purkinje cell dendrites increased greatly during pregnancy and reached 97% of the adult value at birth. On the other hand, 41% of the adult dendritic field width and 11% of the adult area had been attained at birth. The physical size of dendrites increased in a more lagged phase than the dimensions, and growth proceeded mainly after birth. These observations indicate that after the maximum complexity and fundamental tree pattern have been attained, the overall tree size further increases. It is observed that phylogenetic development of dendritic trees of Purkinje cells in several species of vertebrates showed a correlation with the increase in dimensions. These studies demonstrated the potency of the fractal analysis in evaluating development of dendritic trees of neurons.

Aging↗
PubMed1992

Effects of danazol at the immunologic level in patients with adenomyosis, with special reference to autoantibodies: a multi-center cooperative study.

OBJECTIVE: We attempted to evaluate the effects of danazol on autoantibodies, in particular, to phospholipids, and on the immune system in patients with adenomyosis. STUDY DESIGN: Forty-two patients with adenomyosis who had high titers of autoantibodies were randomly chosen, and they received 400 mg/day of danazol for 4 months (n = 22) or underwent hysterectomy (n = 20). RESULTS: Among the six autoantibodies we investigated, the incidence of antiphosphatidylinositol immunoglobulin G was the highest (42.9%), followed by antiphosphatidylglycerol immunoglobulin G (38.1%). The autoantibody titers decreased with time and were comparable to the control values 16 weeks after treatment in both groups. Total serum levels of immunoglobulin G and M were high before treatment, but immunoglobulin M levels decreased significantly in week 8 during treatment with danazol, whereas C4 levels increased and C3 levels decreased with danazol. CONCLUSION: Danazol has an inhibitory effect on the autoimmunologic response associated with adenomyosis.

Autoantibodies↗
PubMed1992

Retrograde supernormal conduction, gap phenomenon in concealed accessory atrioventricular pathways.

We present four patients with the Wolff-Parkinson-White syndrome who exhibited retrograde supernormal conduction or gap phenomenon in concealed accessory pathways. In the first patient, ventricular extrastimulus testing revealed retrograde block at the coupling interval of 520 msec and reappearance of conduction at the coupling interval of 370 msec. In a second patient, 1:1 retrograde conduction was not present but supernormal conduction was demonstrated at coupling intervals of 360 msec to 310 msec during the ventricular extrastimulus testing when the basic drive consisted of atrioventricular (AV) simultaneous pacing. In a third patient, ventricular extrastimulus testing demonstrated retrograde conduction through the accessory pathway only at coupling intervals of 400 msec to 360 msec. In a fourth patient, retrograde block occurred at the coupling interval of 340 msec and retrograde "slow" conduction reappeared at coupling intervals of 300 msec to 250 msec (gap phenomenon) only when the basic drive consisted of AV simultaneous pacing. Thus, concealed accessory pathways may exhibit retrograde supernormal conduction or gap phenomenon. Ventricular extrastimulus testing consisting of AV simultaneous pacing during the basic drive may facilitate demonstration of these unusual properties.

Adult↗
PubMed1992

Solid and papillary epithelial neoplasm of the pancreas: MR imaging and pathologic correlation.

Correlation of magnetic resonance (MR) imaging findings and those at pathologic evaluation was attempted in six cases of solid and papillary epithelial neoplasm of the pancreas. All patients were female, and the mean patient age was 26 years (range, 13-73 years). On T1-weighted spin-echo images, tumors were well demarcated, and areas of high signal intensity were evident within them. At macroscopic examination, these areas corresponded to solid portions with marked hemorrhagic necrosis or cystic portions filled with hemorrhagic debris. In three of four masses surrounded by macroscopically evident fibrous capsules, a rim of low intensity was revealed at T1-weighted imaging. When T1-weighted spin-echo imaging reveals obvious areas of high intensity within a sharply marginated tumor of the pancreas, especially in a young woman, solid and papillary epithelial neoplasm might be a primary diagnostic consideration.

Adolescent↗
PubMed1991

[Iron oxide-enhanced MR imaging of hepatocellular carcinoma of woodchuck].

To determine the utility of iron oxide-enhanced MR imaging for primary hepatocellular carcinoma (HCC), MR imagings of an adult woodchuck with two nodules of HCC was obtained before and after an injection of iron oxide. On postcontrast images, signal intensity decreased in one nodule and did not change in the other. Pathologically, the former was well-differentiated HCC with trabecular pattern and the latter was with pseudograndular and scirrhous pattern. Iron oxide particles were noted within the former. Iron oxide-enhanced MR imaging is a promising method for differentiation of pathological subtypes of HCC, however well-differentiated one with reticuloendothelial cells might be overlooked.

Animals↗
PubMed1991

Occupancy of the majority of DNA in the chicken W chromosome by bent-repetitive sequences.

Another family of repetitive sequences, designated the EcoRI family, was found in the DNA of the chicken W chromosome by hybridization with the W chromosome-specific XhoI family probe under conditions of low stringency. A 1.2 kb EcoRI fragment, the major repeating unit of the family, was cloned and sequenced. The 1.2 kb unit showed an overall sequence similarity of about 68% to the 0.7 kb XhoI family repeating unit and it consisted of tandem repeats of average length 21 bp, most of which contained (A)3-5 and (T)3-4 clusters separated by 6-8 G + C-rich sequences. These features and its behavior as a strongly bent molecule in solution were very similar to those found for other W chromosome-specific repetitive sequences in the order Galliformes: XhoI family of chicken, PstI family of turkey and TaqI family of pheasant. The cloned 1.2 kb unit contained 78 CpG dinucleotide sequences and those that were in HapII, HhaI and BstUI sites were shown to be extensively methylated in the genomic DNA. Repetition frequencies of the 1.2 kb unit among the female population of chicken fell into high- and low-level classes, which accounted for about 30% and 10%, respectively, of the DNA in the W chromosome. Thus, 70% to 90% of the DNA in the chicken W chromosome was shown to be occupied by bent-repetitive sequences. The EcoRI and XhoI family sequences were not intermingled over the short range but each family formed a unique domain ranging from one to several million base pairs.

Animals↗
PubMed1991

Primary adenocarcinoma of duodenal bulb benefitted by chemotherapy.

A 48-year-old man had primary adenocarcinoma of the duodenal bulb. The extensive hepatic metastasis of the patient did not allow any major surgical procedure. Therefore UFTM chemotherapy was performed and was associated with three years of improvement. Subjective symptoms were relieved and test findings indicated normalization of liver biochemistry as well as CEA and CA 19-9. X-ray, endoscopy, and pathological findings indicated the disappearance of the carcinoma of the duodenal bulb. In addition, both ultrasonic examination and CT of the abdomen showed marked reduction of the hepatic metastasis. The authors do not hesitate to recommend the UFTM therapy as a therapeutic modality for inoperable and metastatic primary adenocarcinoma of the duodenum.

Adenocarcinoma↗
PubMed1991

Magnetic resonance imaging of macroscopic intrahepatic portal-hepatic venous shunts.

Direct communication between portal branches and the hepatic vein [macroscopic intra-hepatic portal-hepatic venous shunt (IPHVS)] is a rare entity. We have recently studied five patients with this condition. Magnetic resonance imaging (MRI) clearly demonstrated in each case the portal-hepatic venous shunt due to "flow void." Multiple diffuse shunts were present in one case and a solitary shunt was demonstrated in the others. The solitary shunt was either tubular, focally dilated or racemose in configuration. The MRI findings and clinical significance of this rare entity are discussed.

Adult↗
PubMed1991

CT and MR appearance of focal nodular hyperplasia of the liver in children with biliary atresia.

Two children with biliary atresia are described in whom focal nodular hyperplasia of the liver occurred following portoenterostomy. The lesions were low-or iso-dense on unenhanced CT and became hypodense post-contrast enhancement. There was normal 99mTc phytate on hepatic colloid scintigraphy. On T2-weighted spin echo MR images, there was increased signal intensity within the masses, and the surrounding liver parenchyma was divided by linear septa in one of the two cases.

Biliary Atresia↗
PubMed1991

MR differentiation of hepatic haemangioma and hepatocellular carcinoma: value of delayed-phase Gd-DTPA enhanced images.

The efficacy of three different approaches (precontrast and delayed-phase postcontrast T1-weighted (T1-W) images, measurement of T2 value, and dynamic FLASH imaging) for differentiation between hepatic haemangiomas and hepatocellular carcinomas, was compared. Most haemangiomas (89%) showed iso- or hypointensity on precontrast T1-W images and hyperintensity on delayed-phase postcontrast T1-W images. By using both pre/postcontrast T1-W images and T2 measurement, 30 out of 32 lesions (94%) were correctly differentiated. The dynamic FLASH imaging did not significantly improve the overall accuracy although it played a critical role in a few problematic cases. It is concluded that the combination of pre/postcontrast T1-W images is a promising approach for differentiation of small hepatic tumours, and plays a complementary role with T2 measurement.

Adult↗
PubMed1991

Embolization with steel coils using a saline flush technique.

A method using saline flush to push Gianturco steel coils through catheters is described, and has been successfully used in 45 patients. The saline flush technique requires no precise matching of coils and catheters, solves problems associated with the conventional method and simplifies the coil embolization procedure.

Arteries↗
PubMed1991

[Catheter ablation].

Explore the source record for details and available documents.

Arrhythmias, Cardiac↗
PubMed1990

[Thin-section computed tomography of the normal minor fissure].

The minor fissure was studied with thin computed tomographic (CT) sections (2 mm thickness, 3 mm interval) in 50 patients. It showed high density line or area in all patients. In nine patients CT sections were not obtained through the all region of the minor fissure. Of other 41 patients the fissure was complete in 12 (29%), slightly incomplete in 18 (44%), half incomplete in 7 (17%), and considerably incomplete in 4 (10%). The upper surface of the middle lobe appeared to be upwardly convex in all 50 patients. The location of the highest portion of the minor fissure was hilar in 12 (24%) of 50 patients, medial 1 (2%), anterior 0 (0%), lateral 8 (16%), posterior 3 (6%), dorsal 10 (20%), central 12 (24%), others 2 (4%), and indeterminate 2 (4%). The minor fissure was higher medially than laterally in 22 (44%) patients, and higher posteriorly than anteriorly in 40 (80%) patients. The lowest portion of the minor fissure was anterior in 20 (40%) patients, lateral in 4 (8%), and posterior 3 (6%). The anterior vein of the anterior segment of the right upper lobe (V3b) came in contact with the minor fissure in 20 (40%) patients. In 18 (90%) of these 20 patients minor fissure medial to V3b was incomplete partially. Three dimensional reconstruction image of the minor fissure improved understanding of the anatomy. Familiarity with the anatomic detail of the minor fissure and with variations in the relationships of the upper and middle lobes is useful in localization or extension of a lesion.

Adult↗
PubMed1990

The distribution of serotonin immunoreactivity in the rat locus ceruleus after intraventricular injections of either 5,6- or 5,7-dihydroxytryptamine with special reference to serotonin synthesis.

The localization of serotonin-immunoreactivity (5-HT-IR) in the locus ceruleus (LC) of rats was studied by the peroxidase-anti-peroxidase method using a purified antibody obtained from a rabbit. Antibody production was performed according to the method of Grota and Brown (1974). The antibody was applied to serial cryostat sections with alternate counterstaining by cresyl violet, after intraventricular injections of 5,6-dihydroxytryptamine or 5,7-dihydroxytryptamine prior to treatment with pargyline and a precursor of 5-HT. The majority of LC neurons were immunopositive, and more than half of all LC neurons clearly showed 5-HT-IR. Although core cells were the most predominant, all types of neurons were immunopositive, and randomly scattered throughout the LC. The uptake inhibitor, Lilly 110140, administered in sufficient amounts prior to an injection of pargyline, did not reduce 5-HT-IR within the LC. The results suggest that LC neurons receive 5-hydroxytryptophan (5-HTP) through an afferent vascular-neuronal channel and/or by diffusion from blood capillaries much more than 5-HT itself. We consider from these results that all types of LC neurons throughout the nucleus are masked 5-HT cells, and that the majority of LC neurons utilize blood-borne 5-HTP as an immediate precursor for intraneuronal 5-HT synthesis.

5,6-Dihydroxytryptamine↗