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Biomedical subjects

K Toyama

Publications and source records attributed to K Toyama.

646 records · Page 36Linked to original sources
PubMedDate not supplied

Detection of hepatocellular carcinoma and its metastases with various pulse sequences using superparamagnetic iron oxide (SHU-555-A).

BACKGROUND: To identify the most useful combinations of various pre- and postcontrast magnetic resonance (MR) image sequences in detecting hepatocellular carcinoma (HCC) and its intrahepatic metastases before and after injection of SHU-555-A. METHODS: Thirty-eight lesions in 16 patients were evaluated before and after administration of SHU-555-A by using fast spin echo (FSE), gradient echo (GRE), and echo planar (EP) imaging sequences using a 1.5-Tesla superconducting MR system. The signal intensity ratio (SIR) and contrast-to-noise ratio (CNR) of the lesions, signal-to-noise ratios, and other parameters were calculated. RESULTS: Tumors were better detected after injection of SHU-555-A on all pulse sequences except on out-of-phase T1-weighted (T1W)-GRE sequences. Tumor detectability was higher for precontrast EP imaging and T2*-weighted (T2*W)-GRE sequences, whereas detectability at postcontrast was higher for T2*W-GRE, proton-density-weighted-FSE, and in-phase T1W-GRE sequences. The SIR and CNR at precontrast were highest for EP imaging, and those at postcontrast were highest for T2*W-GRE. CONCLUSION: SHU-555-A will increase the detectability of HCC and its liver metastases. T1W- and T2*W-GRE sequences would be the sequences of choice.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Determination of phosphate ions with an enzyme sensor system.

An enzyme sensor system for the determination of phosphate ions was constructed using immobilized enzymes and an oxygen electrode. The principle of this method is based upon the nucleoside phosphorylase catalyzed reaction for which the presence of inorganic phosphorus is indispensable. One assay could be completed within 3 min. This enzyme sensor was able to withstand at least 70 assays. This system was applicable to simple, rapid and continuous determination of phosphate ions in food.

Biosensing Techniques↗
PubMedDate not supplied

The effect of temperature on the electrochemical properties of copper-DNA membranes.

The influence of temperature, electrode plate metals and protamine on the membrane potential of an electrochemically prepared copper-DNA (Cu-DNA) membrane (size, 2.5 X 6 cm; thickness, 80 micron; Cu/P molar ratio, 0.4) was investigated. The results obtained showed that the membrane potential increased with temperature as well as with increasing order of ionization tendency of the divalent metals used, and decreased with an increase of protamine bound to the membrane. These results indicated that electrons accumulated on the anode side, and positive holes formed on the cathode side, of a Cu-DNA membrane prepared by electrolysis.

Copper↗
PubMedDate not supplied

Three recessive genes for congenital osteopetrosis in Norway rat.

In the rat, the autosomal recessive toothless (t1) mutation exhibits an acute form of osteopetrosis. This gene is not an allele of either ia or op that causes respectively, a transitory and acute form of the disease. Comparative radiographic study of t1/t1 and op/op mutants reveals some differences in respect to the size and shape of long bones. In contrast to op/op mutants, homozygous t1/t1 animals failed to respond to either parabiosis or bone marrow transplants.

Alleles↗
PubMedDate not supplied

Presence of Philadelphia (Ph) chromosome-negative cells in Ph-positive chronic myelogenous leukemia.

Six cases of chronic myelogenous leukemia (CML) with coexistence of cells with a Philadelphia (Ph) translocation and a normal karyotype are described. Molecular analyses were performed in 3 of the 6 cases at two phases with different cytogenetic findings. Among the 6 cases, 4 cases were late appearance of a Ph chromosome. Two of the 3 patients analyzed had major breakpoint cluster region (Mbcr) rearrangements; aberrant Mbcr fragments were observed whether the cells had a Ph translocation or not. The remaining one did not show any rearrangements within the Mbcr DNA sequences.

Adult↗
PubMedDate not supplied

Prognostic factors in stage I and II non-Hodgkin's lymphoma of Waldeyer's ring.

Sixty-nine stage I and II patients treated for non-Hodgkin's lymphoma of Waldeyer's ring were retrospectively analysed. Diffuse histiocytic lymphoma (Rappaport's classification) was the most common histology (67%). Staging without laparotomy revealed 31 patients in stage I and 38 in stage II. Sixty-five patients received radiation therapy against involved or extended fields. In 43 patients adjuvant chemotherapy with single or multiple agents was given and 4 patients received only chemotherapy. A relapse occurred in 34 (49%) patients. The 5-year relapse-free survival was 67 per cent and 36 per cent in stage I and stage II, respectively. Radiation doses of 50 Gy gave no recurrence within treated volumes. However, since relapse below the clavicles and especially below the diaphragm was common, the radiation doses did not seem important for reduction of the overall failure rate. In stage II, patients with a single neck node less than 5 cm in diameter seemed to have a better prognosis than patients with large or multiple neck nodes. In this non-randomized study adjuvant chemotherapy seemed to reduce the risk of relapse, especially in stage II patients.

Adolescent↗
PubMedDate not supplied

Nodular duodenitis involving CD8+ cell infiltration in patients with ulcerative colitis.

BACKGROUND/AIMS: Limited efforts have been made to determine changes in the upper gastrointestinal tract in ulcerative colitis. The aim of this study was to analyze gastroduodenal lesions in patients with ulcerative colitis. METHODOLOGY: The endoscopical appearance of lesions in the duodenum and stomach was first examined. Biopsy specimens taken from 25 patients with ulcerative colitis, as well as 21 with Crohn's disease and 16 with nonspecific gastroduodenitis who had no Helicobacter pylori infection, were then evaluated by histology and immunohistochemistry for CD8, CD68 and HLA-DR. In ulcerative colitis patients, the HLA-phenotype was also analyzed by the standard NIH complement-dependent microlymphocyte toxicity assay. RESULTS: Endoscopically evident alteration of nodularity in the descending part of duodenum was prominent in ulcerative colitis and Crohn's disease, but not gastroduodenitis. Histological inflammatory change of the duodenal bulb in ulcerative colitis and Crohn's disease was mild as compared to gastroduodenitis cases. Endoscopic and histological change (redness and deformity of villi) in the duodenum were more prominent in ulcerative colitis patients with pancolitis than those with left-sided/proctitis. CD8+ cells infiltrating both the duodenum and stomach were increased in ulcerative colitis and Crohn's disease as compared to gastroduodenitis whereas focal perifoveolar accumulation of CD68+ cells and enhanced epithelial expression of HLA-DR were characteristic of Crohn's disease. Histopathological alteration in the duodenum was particularly prevalent in ulcerative colitis patients with HLA-DR4 and Cw1. CONCLUSIONS: Nodular, histologically mild duodenitis involving CD8+ cell infiltration, the severity of which positively correlates with the extent of colitis, is characteristic of ulcerative colitis.

Adolescent↗