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Biomedical subjects

S Ohta

Publications and source records attributed to S Ohta.

910 records · Page 51Linked to original sources
PubMedDate not supplied

Localization of double, roentgenographically occult lung cancer. Cytologic findings from selective brushing of all segmental and subsegmental bronchi.

Using selective brushing of all segmental and subsegmental bronchi, six patients were diagnosed as having synchronous, double, roentgenographically occult lung cancers. Experienced bronchoscopists failed to detect four "second cancer" lesions in six patients. The appearance of atypical cells as shown by cytologic examination indicated the probability of the presence of cancer in the examined bronchus. Single cancer cells or tiny clusters of cells with orangeophilic cytoplasm can appear in specimens obtained from all bronchi, and such cells should not be considered to have originated in the bronchi under examination. Medium-sized or large clusters of cancer cells without degeneration and with basophilic cytoplasm appear only in specimens obtained from bronchi in which a cancer lesion exists, and thus they should be considered to have originated in the bronchi under examination. Cancer cells with orangeophilic cytoplasm in clusters should be considered to have originated in unknown locations. To determine the origin of such cells, one must compare the specimens with those obtained from other segmental and subsegmental bronchi. Our findings suggest that selective brushing of all segmental and subsegmental bronchi is a useful method of detecting unrecognizable second cancers and that the method should be employed for all patients with positive sputum cytology.

Aged↗
PubMedDate not supplied

Different binding properties of three monoclonal antibodies to sialyl Le(x) glycolipids in a gastric cancer cell line and normal stomach tissue.

We established a mouse monoclonal antibody (Mab) KM93 which recognized sialyl Le(x)-carbohydrate epitope determined by solid phase radioimmunoassay using a panel of authentic glycolipids. The specificity of KM93 was similar to another anti-sialyl Le(x) Mab CSLEX-1 established previously, and different from that of Mab FH6 which recognized sialyl Le(x)-i (sialyl dimeric Le(x)). In a further study, however, we found that KM93 reacted with some glycolipids much more strongly than CSLEX-1 did on thin-layer chromatography (TLC) plates. We purified two gangliosides named K-1 and K-2 from gastric cancer cell line KATOIII, and three gangliosides named H-1, H-2, and H-3 from human stomach. KM93 reacted with all of these glycolipids. CSLEX-1 reacted with K-1 and K-2 with less intensity than KM93 did, and faintly reacted with H-1, but not at all with H-2 or H-3. FH6 did not react with K-1, K-2 or H-1, while it stained H-2 and H-3. In spite of this different reactivity with Mabs, analysis by proton nuclear magnetic resonance (1H NMR) proved that carbohydrate structure of K-1 and H-2 were the same: NeuAc alpha 2-->3Ga1 beta 1-->4 [Fuc alpha 1-->3] G1cNAc beta 1-->3 Ga1 beta 1-->4G1c beta 1-->1Cer. The H1 NMR spectrum of H-3 also indicated that H-3 consisted of the same sugars as K-1. These results indicated that KM93 had wider reactivity than CSLEX-1, and that the distinct reactivity of KM93 from CSLEX-1 was not caused by sugar moiety. It was also shown that the interaction of sialyl Le(x) sugar determinant with MAb depended on the tissue origin of molecules carrying carbohydrate.

Amino Acid Sequence↗
PubMedDate not supplied

Suramin inhibits the phosphorylation and catalytic activity of DNA topoisomerase II in human lung cancer cells.

Suramin is a prototype of a new class of anticancer drugs. We investigated the action of suramin on the signal transduction pathways to DNA topoisomerase II (Topo II). Suramin showed a growth-inhibitory effect on a human lung cancer cell line (PC-9) with an IC50 of about 160 micrograms/ml. Suramin inhibited the catalytic activity of Topo II with an IC50 of about 100 micrograms/ml without stabilization of the cleavable complex of DNA and Topo II. Suramin decreased the phosphorylation of Topo II with an IC50 of 175 micrograms/ml, but did not change the degree of Topo II expression. These IC50 values for inhibition of catalytic activity and phosphorylation of Topo II were equivalent to the growth-inhibitory dose determined by tetrazolium dye assay. Phosphorylation of the tyrosine residues of Topo II was not changed by suramin. In the presence of okadaic acid, a potent inhibitor of serine/threonine protein phosphatase, suramin also decreased the phosphorylation of Topo II, suggesting that the drug did not act on the serine/threonine protein phosphatases inhibited by okadaic acid. Suramin also inhibited the protein kinase C (PKC) activity of PC-9 cells. These results suggest that suramin decreases the phosphorylation of Topo II mediated by PKC. This effect of suramin might cause the inhibition of Topo II activity resulting in the growth inhibition of tumor cells.

Blotting, Western↗
PubMedDate not supplied

Immunocytochemical study on internalization of anti-carbohydrate monoclonal antibodies.

The fate of anti-tumor monoclonal antibodies (mAbs) after binding to the cell surface is one of the important factors for application of mAbs in therapy. For mAbs to remain on the cell surface for a long time is preferable character for complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC). On the other hand, quick internalization of mAbs into cytoplasm is advantageous for cytotoxic effects of toxins or cytotoxic drugs conjugated with mAbs. In this study we investigated the localization of anti-carbohydrate mAbs in vitro by immunocytochemical methods at the electron microscopic level. Anti-ganglioside GM3 mAb (mouse IgM) was localized both in cytoplasmic vesicles and on the cell surface membrane of mouse melanoma cells after incubation for 30 min at 37 degrees C. Anti-ganglioside GM2 mAb (mouse IgM), anti-ganglioside GD2 mAb (mouse IgG3) anti-ganglioside GD3 mAb (mouse IgG3) mainly existed on the cell surface of human small cell lung carcinoma cells, human neuroblastoma cells and human melanoma cells, respectively, after incubation for 30 min at 37 degrees C. On the other hand, anti-sialyl Lea mAb (mouse IgG1) was intensively incorporated into the cytoplasm of human colon tumor cells under the same conditions. Anti-ganglioside GD3 mAb and anti-sialyl Lea mAb were radiolabelled with 125Iodine and traced in in vitro culture. When the cells were incubated in the presence of the 125I-mAb for 90 min on ice, the ratio of intracellular counts to surface counts was 8/92 for anti-ganglioside GD3 mAb and 31/69 for anti-sialyl Lea mAb respectively. After the subsequent incubation for 60 min at 37 degrees C, the ratio altered to 13/87 for anti-ganglioside GD3 mAb and 54/46 for anti-sialyl Lea antigen mAb. This study suggested that internalization of anti-carbohydrate mAbs after the binding to the cell surface was different among the mAbs depending on the character of antigens. In conclusion, anti-ganglioside mAbs have beneficial characters for CDC or ADCC while anti-sialyl Lea mAb is suitable for immunoconjugates.

Animals↗
PubMedDate not supplied

Diagnostic and therapeutic strategies of pyogenic liver abscess.

The infectious routes and etiologies of 26 cases with pyogenic liver abscess were portal spread in one, hematogenous in three, biliary in 12, transarterial embolization (TAE) in three, posthepatectomy in one and cryptogenic in five cases. Portal and hematogenous cases tend to show solitary and cystic pattern on echogram, and the majority of the bacteria detected was Klebsiella. While most biliary cases show multiple and cystic with tumor pattern on echogram, and an unhomogeneous low density in CT feature, anaerobic bacteria and candida were isolated only from the biliary or TAE cases. Most cases could be cured completely by the various kinds of abscess drainage, but two TAE cases with PTAD (percutaneous transhepatic abscess drainage) and two biliary cases with PTBD (PT-biliary drainage) and PTAD died due to a delay in establishing a diagnosis and to the severity of the condition. An early diagnosis followed by PTAD or PTBD were thought to be of prime importance.

Anti-Bacterial Agents↗
PubMedDate not supplied

Cytotoxicity of adriamycin-containing immunoliposomes targeted with anti-ganglioside monoclonal antibodies.

GM2 and GD2 have been intensely studied as tumor antigens of neuroectodermal-origin tumors. We have established several mouse or rat IgM anti-ganglioside GM2 and GD2 MoAbs and applied them in antigen-specific drug delivery. In the immunofluorescence assay, anti-GM2 MoAbs bound to neuroblastoma cells and leukemia cells, and anti-GD2 MoAb bound to neuroblastoma cells and melanoma cells. Sulfhydryl subunits of reduced IgM were directly coupled to maleimide groups on the surface of the liposomes followed by the incorporation of adriamycin by the use of Na+/K+ chemical gradient. The resultant immunoliposomes had a size of 86 nm-diameter containing approximately 400 molecules of adriamycin in its unilamellar structure and 17 molecules of the MoAb on its surface. Mouse anti-GM2 MoAb lost the binding specificity when covalently bound to the liposomes. The immunoliposome coupled with mouse anti-GD2 MoAb retained targeting activity to the antigen-positive neuroblastoma cells, IMR-32. However, it did not kill IMR-32 cells, probably because the amount of adriamycin taken up by the tumor cell was below the fatal amount. The immunoliposome coupled with rat anti-GM2 MoAbs delivered adriamycin to the neuroblastoma cells, IMR-32, and leukemia cells, TYH, in the antigen-specific manner. It also target-specifically suppressed the (3H)thymidine-uptake of the cells while the same concentration of adriamycin in the free form killed all the cell lines examined. IMR-32 cells had GM2 and GD2 in almost the same amounts, and interacted with either mouse anti-GD2 MoAb--immunoliposome or rat anti-GM2 MoAb-immunoliposome. The different cytotoxic activities of the two immunoliposomes against IMR-32 cells was probably due to the difference in the facility of internalization of the immunoliposomes after binding.

Animals↗
PubMedDate not supplied

Different distribution of dihydrolipoamide succinyltransferase, dihydrolipoamide acetyltransferase and ATP synthase beta-subunit in monkey brain.

The distribution of three mitochondrial enzymes: dihydrolipoamide succinyltransferase, dihydrolipoamide acetyltransferase, and beta-subunit of ATP synthase, were examined in the nucleus basalis of Meynert, substantia nigra, locus coeruleus, hippocampus, and cerebral cortex of monkey brain by immunocytochemical staining. Dihydrolipoamide succinyltransferase and dihydrolipoamide acetyltransferase had parallel distribution in the substantia nigra, but dihydrolipoamide acetyltransferase was rich in the locus coeruleus, nucleus basalis of Meynert, and especially in the hippocampus in comparison with dihydrolipoamide succinyltransferase. The ATP synthase beta-subunit was strikingly rich in many neurons of the locus coeruleus and cerebral cortex in comparison with dihydrolipoamide acetyltransferase and dihydrolipoamide succinyltransferase. These results show that these mitochondrial enzymes are not expressed synchronously in the neurons of brain, suggesting the differential regulation of mitochondrial enzymes and the heterogeneity of mitochondria.

Acetyltransferases↗
PubMedDate not supplied

Apoptosis of androgen-independent mammary and prostate cell lines induced by topoisomerase inhibitors: common pathway of gene regulation.

New treatments for hormone-independent tumor are urgently needed since androgen-dependent cancer cells eventually progress to -independent cells after hormonal manipulation. In the present study, etoposide and camptothecin were used to induce proliferation-dependent death of these cells. Each of the agents, at the doses used, induces the apoptosis of AT-3, CS 2, and TSU-pr1 cells based upon the temporal sequence of DNA fragmentation, morphologic changes and loss of cell viability. Northern blot analysis was used to identify a series of genes whose expression is enhanced during the apoptotic pathway. During the apoptotic process induced by the agents, expression of cyclin-dependent kinase inhibitor p27 increased. Flow cytometric analysis showed that the treatment resulted in a block in G2/M of the cell cycle. These results demonstrate that these cells retain the ability to undergo apoptosis by etoposide and camptothecin, and cyclin-dependent kinase inhibitor plays some role during apoptotic pathway.

Androgens↗
PubMedDate not supplied

Enhanced expression of cyclin-dependent kinase inhibitor in apoptosis of androgen-independent prostatic cancer cell line induced by calcium ionophore.

In order to examine the relationship between apoptosis of androgen-independent prostatic cancer cells and cell cycle-associated proteins, TSU-pr1 human prostatic cancer cells were chronically exposed in vitro to the calcium ionophore ionomycin to sustain an elevation in their intracellular free calcium concentration. Temporal analysis demonstrated that the death of these cells does not require cell proliferation and involves fragmentation of genomic DNA into nucleosome sized pieces. Morphological analysis demonstrated that this death process is via apoptosis. During the apoptotic process induced by ionomycin, expression of cyclin-dependent kinase inhibitor p27Kip1 increased. Flow cytometric analysis showed that the treatment resulted in a block in G0/G1 of the cell cycle. These results demonstrate that even nonproliferating androgen-independent prostatic cancer cells can be induced to undergo apoptosis if a modest elevation in the intracellular free calcium is sustained for a sufficient time. p27Kip1 protein is a candidate for the cell cycle regulator in ionomycin-treated TSU-pr1 cells.

Androgens↗