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D J Adamson

Publications and source records attributed to D J Adamson.

31 records · Page 2Linked to original sources
PubMed1983

Biological effects and structure-activity relationships of 1,2-dihydropyrido[3,4-b]pyrazines.

The effects of a number of 1,2-dihydropyrido[3,4-b]pyrazines (1-deaza-7,8-dihydropteridines) upon the proliferation and the mitotic index of cultured L1210 cells and upon the survival of mice bearing P388 leukemia were determined. The 1,2-dihydrostructure and amino groups or masked amino groups at positions 5 and 7 were necessary for activity, and various substituents at positions 2 and 3 had considerable influence upon the activity. A number of these pyrazines had significant activity against i.p. P388 leukemia in mice, and several pyrazines were more active than the corresponding oxazines or thiazines in both the in vitro and the in vivo systems. The effects of the pyrazines upon the cultured cells were reversible, and the rate and degree of reversibility were influenced by the substituents at positions 2 and 3. Tests performed with two of the pyrazines yielded results that indicate that these compounds, like the known agent nocodazole, might compete with colchicine for binding to tubulin. Synergistic killing of cultured L1210 cells was obtained with combinations of one of the pyrazines and vincristine.

Animals↗
PubMed1982

Inhibition of mitosis and anticancer activity against experimental neoplasms by ethyl 5-amino-1,2-dihydro-3-[(N-methylanilino)methyl]-pyrido[3,4-b]pyrazin-7-ylcarbamate (NSC 181928).

Ethyl 5-amino-1,2-dihydro-3-[N-methylanilino)methyl]pyrido[3,4-b]pyrazin-7-ylcarbamate (NSC 181928) is reported to be active against several experimental neoplasms. The experimental data obtained in the present study indicate that it causes the accumulation of cells at mitosis with both cultured cells and ascites cancer cells in vivo. This effect was observed with L1210, P388, colon cancer 26, colon cancer 38, and H.Ep. 2 cells in culture and with L1210 cells and P388 cells in mice. The agent was also active in vitro and in vivo against a line of leukemia P388 cells that are resistant to vincristine.

Animals↗
PubMed1980

Effects of N,N'-bis(2-chloroethyl)-N-nitrosourea and 2-[3-(2-chloroethyl)-3-nitrosoureido]-2-deoxy-D-glucopyranose upon the proliferation, DNA synthesis, and viability of cultured sensitive and resistant L1210 cells.

The effects of N,N'-bis(2-chloroethyl)-N-nitrosourea and chlorozotocin upon the proliferation, DNA synthesis, and viability of cultured cells of a sensitive line of L1210 leukemia, a line partially resistant to N,N'-bis(2-chloroethyl)-N-nitrosourea, and a line resistant to cyclophosphamide were determined. The results indicate that neither the effect upon proliferation nor the effect upon DNA synthesis is a good predictor of the extent of cell kill. The similarity of the effects of N,N'-bis(2-chloroethyl)-N-nitrosourea upon these two parameters for the three cell lines indicates that the sensitive and resistant cells are affected to approximately the same extent, but more of the resistant cells survive. Additional studies are required to seek the reasons for this differential survival.

Animals↗
PubMed1976

Studies with 2,5-piperazinedione, 3,6-bis(5-chloro-2-piperidyl)-,dihydrochloride. I. Cell kinetic and biologic effects in cultured L1210, human epidermoid No. 2, and adenocarcinoma 755 cells.

Experimental results obtained with cultured L1210, human epidermoid No. 2, and Adenocarcinoma 755 cells are consistent in showing that inhibition of proliferation of the cells by 2,5-piperazinedione, 3,6-bis(5-chloro-2-piperidyl)-,dihydrochloride is accompanied by cell enlargement. Although cells initially in the G2 phase when exposure to the agent is begun can probably proceed through mitosis and divide, cells that are initially in G1 and S phases accumulate in the G2 phase. Progression of cells to G2 phase during the period of exposure to the agent is not a requisite for cell-killing, because cells exposed for periods insufficient to permit their accumulation in G2 are killed.

Adenocarcinoma↗
PubMed1975

Mechanisms of action of 6-thioguanine, 6-mercaptopurine, and 8-azaguanine.

The effects of 6-thioguanine on purine biosynthesis and cell viability have been examined in H.Ep. 2 cells grown in culture. Toxicity is not reversed by aminoimidazolecarboxamide, suggesting that inhibition of purine biosynthesis de novo is not the sole mechanism of toxicity. Also, 6-(methylmercapto)purine ribonucleoside, a potent inhibitor of purine biosynthesis de novo, produces more marked reductions in cellular pools of purines than does 6-thioguanine without killing cells. There is no apparent inhibition by 6-thioguanosine 5'-monophosphate of other enzymes leading to the synthesis of guanosine 5'-triphosphate as determined in whole cells by measurements of radioactive hypoxanthine or guanine incorporation. Inhibition of DNA synthesis by 1 mM thymidine protects cells from 6-mercaptopurine or 6-thioguanine but fails to protect cells from 8-azaguanine toxicity. On the other hand, inhibition of RNA synthesis by 6-azauridine plus deoxycytidine protects cells against 8-azaguanine but does not protect against 6-thioguanine or 6-mercaptopurine toxicity. In agreement with the in vitro data, arabinosylcytosine (a potent inhibitor of DNA synthesis) fails to protect mice against 8-azaguanine but has previously been shown to protect mice from 6-mercaptopurine or 6-thioguanine toxicity. The results support the hypotheses of others that incorporation into DNA (as 6-thioguanine nucleotide) is a mechanism of toxicity for these thiopurines, whereas 8-azaguanine is toxic due to its incorporation into RNA.

Azaguanine↗
PubMedDate not supplied

Occult malignancy is associated with venous thrombosis unresponsive to adequate anticoagulation.

The increased incidence of intravascular thrombosis and thromboembolic episodes in patients with malignant disease is well documented. There have, however, been only two reports of covert malignancy in patients who continue to extend their deep vein thrombosis despite apparently adequate anticoagulation. Three patients are described in whom venous thrombosis steadily worsened despite a prothrombin time of at least twice normal. None had either obvious predisposing factors to thromboembolism or a family history of thrombotic disease. Recognition of this phenomenon can be helpful in avoiding delay in diagnosing malignancy in young patients.

Adult↗