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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An intraepidermally developed epithelial cell tumor, forming multiple nests, was examined to identify its cytologic characteristics. Histochemically, the tumor cells contained neither glycogen nor lipid substance. By N-(7-dimethylamino-3-methyl-4-coumarinyl)maleimide staining, the cytoplasm of the tumor cells in the periphery of each nest was rich in SH groups but not in SS linkages, whereas centrally located homogeneous tumor cells contained SS diffusely but no SH. The tumor cells showed no activity of phosphorylase and a weak activity of succinic dehydrogenase. Immunohistochemically, antihair keratin monoclonal antibodies specific for hair cells decorated the tumor cells, but carcinoembryonic antigen staining showed no positivity. Ultrastructurally, the tumor cells underwent a keratinization forming a fingerprint pattern of keratin filaments; however, membrane-coating granules and marginal bands were not formed. These intraepidermal tumor cells may have cytologic natures similar to those of hair cortical cells. The term intraepidermal pilar epithelioma is proposed as a diagnosis for this tumor.
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PMID:Intraepidermal pilar epithelioma: a new dermatopathologic interpretation of a skin tumor. 245 Jan 9

Solid tumors contain hypoxic cells which are relatively resistant to antineoplastic activity of radiation or to chemotherapeutic agents. We determined the increase in antineoplastic activities of mitomycin C (MMC) and carboquone (CQ) against human tumor cells under conditions of in vitro hypoxia, with the following results. (a) The HeLa cells had been exposed to various concentrations of MMC or CQ for 2 h under normally aerated (about 20%) or hypoxic conditions (5.0 and 0%) and were maintained under normally aerated conditions for 3 days. The succinate dehydrogenase activity was assayed, using the succinate dehydrogenase inhibition (SDI) test. Treatment with MMC or CQ reduced the SD activity, compared to findings in the control cells, under hypoxic conditions. (b) The cells were exposed to the drug, MMC or CQ, under normally aerated or anoxic conditions, for 15-45 min and the colonies counted on day 14. Treatment with 0.45 microM of MMC for 45 min inhibited the clonogenicity of HeLa cells by 25.4% of findings in the control cells under anoxia. Treatment with 0.03 microM of CQ for 30 min inhibited the clonogenicity by 41.5%. (c) The sensitivity of 14 human tumor tissues (6 gastric and 8 colorectal cancers) to MMC or CQ under hypoxic conditions was determined, using the SDI test. MMC and CQ showed hypoxic enhancement. Therefore, MMC and CQ have definite positive effects on hypoxic cells, and hence a higher therapeutic ratio for treating clinical solid tumors.
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PMID:Hypoxia enhances the lethality of mitomycin C and carboquone against human malignant tumor cells in vitro. 250 6

In vitro chemosensitivity was evaluated in human head and neck cancers using the succinate dehydrogenase (SD) test and the results were compared to findings in cases of malignant lymphomas and gastric cancers. Tumor fragments were exposed to several antitumor drugs at ten times the peak plasma concentration and assayed for SD activity. Decrease of SD activity was most prominent in the malignant lymphomas in cases of exposure to ADM, ACR, DDP, MMC and CQ; in which the average of SD activity decreased to below 30%. In the squamous cell carcinomas, SD activity below 40% was also observed with the same drugs, while the SD activity of gastric cancers was about 50%. There was a change of chemosensitivity following chemotherapy. The use of the SDI test will aid in selecting drugs for the prevention of recurrence or metastasis in head and neck cancers.
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PMID:Succinate dehydrogenase inhibition test for evaluating head and neck tumors. 271 26

In order to determine the most effective anticancer agents for individual human tumor, succinic dehydrogenase inhibition test (SDI-T) and adenosine triphosphate inhibition assay (ATP-A) as in vitro chemosensitivity tests were performed. Fifty tumors and 57 tumors derived from cancer patients surgically methods were examined by SDI-T and ATP-A respectively. As the results, the evaluable rate was 70% by SDI-T and 94.7% by ATP-A, respectively. With SDI-T, the positive rate against all tumors was 51.4% in mitomycin-C (MMC), 42.9% in adriamycin (ADM), 20.0% in 5-fluorouracil (5-FU), 54.3% in cis-diamminedichloroplatinum (CDDP). On the other hand, with ATP-A, that was 20.4% in MMC, 29.5% in ADM, 20.6% in 5-FU, 20.4% in CDDP, respectively. Retrospective and prospective clinical trials were also carried out to determine the usefulness of both assays. With SDI-T, overall predictive accuracy rate was 57.1% while with ATP-A that was 88.9%. Furthermore, the rates of sensitivity for the same tumors using SDI-T and ATP-A were compared. The rate of the same sensitive cases in both assays were 30% with MMC, 70% with 5-FU, 42.1% with ADM, 36.8% with CDDP, respectively. In conclusion, it is suggested that ATP-A was more useful than SDI-T as in vitro chemosensitivity test to determine the most adequate drug for cancer patients.
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PMID:[Comparison of succinic dehydrogenase inhibition test with adenosine triphosphate inhibition assay for human solid tumors as in vitro chemosensitivity tests]. 273 92

The sensitivities of 84 human tumor tissues (23 gastric, 8 colorectal cancers, 34 hepatomas, 6 breast, 6 lung cancers and 7 malignant lymphomas) to adriamycin (ADM) and 4'-0-tetrahydropyranyladriamycin (THP-ADM), a semisynthetic anthracycline glycoside, were determined using the in vitro succinate dehydrogenase inhibition (SDI) test. The succinate dehydrogenase (SD) activity of the tumor tissues was assayed following exposure to 6.9 microM of the drug for 3 days; sensitivity was considered positive when the SD activity decreased to below 50% of that of the control cells. In the case of exposure to THP-ADM, the SD activity in the tissue decreased and the decrease was more extensive in the gastric, colorectal cancers, hepatomas, lung cancers, with a statistically significant difference (P less than 0.001-P less than 0.05), but not in the breast cancers and malignant lymphomas. The rate of sensitivity was 70.2% for THP-ADM and 51.2% for ADM in the 84 tumor tissues. The percentage of tissues with a higher sensitivity to THP-ADM, compared to ADM, was 79.8%. As THP-ADM proved to be more cytotoxic than ADM to human tumors in vitro, this drug should be kept in mind when anti-cancer chemotherapy is designed.
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PMID:4'-O-tetrahydropyranyladriamycin has greater antineoplastic activity than adriamycin in various human tumours in vitro. 275 Dec 63

The different distribution of cytochemically demonstrable enzymes: lactate dehydrogenase (LDH, 1.1.1.27), succinate dehydrogenase (SDH, 1.3.99.1), dihydrofolate reductase (DHFR, 1.5.1.3), acid phosphatase (AcP, 3.1.3.2) and alkaline phosphatase (ALP, 3.1.3.1), has been documented in Yoshida ascites hepatoma cells in vivo or stored at 80 degrees C. The dehydrogenase activities (LDH, SDH, DHFR) show a strong reaction in all samples. An increased level of these enzyme activities has been observed in the malignant cells spreading through the organs of tumor bearing rats. On the contrary, in the same samples, acid and alkaline phosphatase activities are very low. The strong dehydrogenase activities observed in Yoshida ascite cells stress the rapid turnover of tumor cells. Our results indicate that the histochemical method may be a useful tool to detect the scattered tumor cells. Furthermore, the cytochemical methods allow the characterization of the metabolic pathways employed by the primary and disseminated tumor cells.
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PMID:[Cytochemical study of cells of primary and disseminated ascite Yoshida tumor cells]. 276 51

The sensitivities to 1-beta-D-arabinofuranosylcytosine (ara-C) and N4-behenoyl-1-beta-D-arabinofuranosylcytosine (BH-AC), a masked compound of ara-C, were determined in 33 human tumor tissues (11 gastric, 6 colorectal cancers and 16 malignant lymphomas), using the in vitro succinate dehydrogenase inhibition test. The succinate dehydrogenase (SD) activity of the tumor tissues was assayed following exposure to the drug at 8.8 or 88 microM for 3 days and the sensitivity was considered positive when the SD activity decreased to below 50% of that of the control cells at 88 microM. The SD activity decreased little at 8.8 microM and decreased individually at 88 microM. The mean of the SD activity at 88 microM was 65.7 +/- 11.5% for ara-C and 61.4 +/- 14.5% for BH-AC in gastrointestinal cancers, and 63.8 +/- 16.0% for ara-C and 58.3 +/- 18.3% for BH-AC in malignant lymphomas with a statistically significant difference (p less than 0.05). BH-AC is converted to ara-C for exertion of the cytotoxic effect and a positive correlation was noted between the SD activities of ara-C and BH-AC (r = 0.825 at 88 microM). The chemosensitivity varied with the tissue and 18% of the tissues were sensitive to ara-C, 27% to BH-AC and 15% were sensitive to BH-AC but resistant to ara-C. Our findings show that ara-C and BH-AC are equally cytostatic to human tumors. The sensitivity test of ara-C and BH-AC enables one to determine which drug is best suited for individual patients.
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PMID:In vitro sensitivity of various human tumors to 1-beta-D-arabinofuranosylcytosine and N4-behenoyl-1-beta-D-arabinofuranosylcytosine. 276 58

Twenty lines of human gastro intestinal and breast cancer xenografts, in which chemosensitivity spectra by the in vivo nude mouse assay had been clarified. were subjected to the in vitro SDI (succinate dehydrogenase inhibition) assay using MTT dye to assess the accuracy of this drug sensitivity test against 4 drugs i.e., mitomycin C (MMC), adriamycin (ADM) 5 fluorouracil (5-FU), and cisplatin (CDDP). After 3 days incubation, the suspension of every tumor cells including small fragments showed a marked decrease of SD activity even when no anticancer drug was added to the assay medium. Among these 4 drugs evaluated MMC exhibited a statistically significant correlation between chemosensitivity values of the in vitro SDI assay and those of the nude mouse assay. However, the other 3 drugs demonstrated no correlation between the values of these two methods. Since the primary cultured fibroblasts revealed, in general, lower sensitivity to these drugs, contamination of fibroblast may decrease the SDI values when materials from solid tumors with rich stroma such as a type of stomach cancer were subjected. It is considered that the prediction of chemosensitivity to every drug will be impossible by a in vitro SDI assay.
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PMID:[Evaluation of predictability of in vitro SDI assay in comparison with in vivo nude mouse assay]. 280 37

Fresh surgical explants of solid tumors obtained from 50 patients were tested against the same chemotherapeutic agents in both the in vivo subrenal capsule (SRC) assay and the in vitro succinate dehydrogenase inhibition (SDI) test. Control growth adequate to meet evaluable assay criteria was obtained in 36 of 50 tumors tested in the SRC assay (72.0%). In the SDI test, 46 of 50 tumors were evaluable (92.0%). Correlations between the two test systems were dependent upon the activity criteria established for each system. With activity criteria set at current drug screening levels as a change of less than or equal to -2.0 in modified PAPAN score (S) for the SRC and an inhibition of greater than or equal to 50.0% in succinate dehydrogenase activity (SD) for the SDI, 12.5% of the drugs tested were active in the SRC and 22.3% were active in the SDI. Correlations of tumor response between the two test systems were 31.7% for sensitive (13/41) and 95.1% for resistant (98/103).
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PMID:Comparison of the subrenal capsule assay and succinate dehydrogenase inhibition test. 280 23

The synthetic "picket fence" porphyrin, tetra(o-acetamidophenyl)porphine (TAc), as a biological photosensitizer has been evaluated both in vitro and in vivo in mitochondria from the R3230AC mammary tumor. Studies in vitro, consisting of incubation of mitochondria with TAc at a concentration of 4.0 micrograms/ml followed by photolysis, result in the inhibition of cytochrome c oxidase, proton translocating ATPase, succinate dehydrogenase, and malate dehydrogenase. The diminution in activity of the first three enzymes is approximately 2-fold greater than that seen with Photofrin II under the same conditions. Although TAc exists as four isolable atropisomers, no differences among these different forms were observed in their photosensitized inhibition of mitochondrial enzymes. Administration to tumor-bearing rats of TAc i.p. at a dose of 25 mg/kg did result in accumulation of porphyrin within the mitochondria of the R3230AC tumor as determined by subsequent irradiation of isolated mitochondria. The potential utility of TAc and related porphyrins in cancer phototherapy is discussed.
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PMID:Picket-fence porphyrins as potential phototherapeutic agents. 283 16


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