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At least 19 recordsLinked to original sources

PubMed1978

[6-(2,4-Dinitrophenyl)-mercaptopurine, a stronger immunosuppressive drug than 6-mercaptopurine to primary humoral T-cell dependent immune response in mice].

The suppressive effect of 6-(2,4-Dinitrophenyl)-mercatopurine (DNP-MP) and 6-mercaptopurine (MP) was investigated on the early primary immune response of mice against the T-cell dependent antigens DNP49-bovine gamma globuline (BGG), sheep red blood cells (SRBC) or FITC8-BCG and the T-cell independent DNP22-Ficoll. The number of IgM antibody forming cells (AbFC) to the hapten determinants and to the SRBCs per 10(6) spleen cells was determined. DNP-MP reduced the number of AbFCs after the immunisation with the T cell dependent antigens always stronger than the MP, independently of the antigen type by which the mice had been immunised. The Anti-DNP22-Ficoll immune response was suppressed equally by both immunosuppressive drugs. DNP-MP is not a specific immunosuppressive drug for the anti-DNP-B-lymphocytes. Helper T-cells and macrophages are discussed as target cells for the stronger unspecific action of DNP-MP.

Animals↗

PubMed1978

The quantitative determination of metabolites of 6-mercaptopurine in biological materials. III. The determination of 14C-labeled 6-thiopurines in L5178Y cell extracts using high-pressure liquid cation-exchange chromatography.

A method is presented for the separation of 6-thiopurine bases and ribonucleosides, of sulphate anions and of common purine bases and oxidized purines by means of high-pressure liquid cation-exchange chromatography using a 0.18 X 100 cm column, filled with Beckman M71 resin, and eluted with 0.4M ammonium formate, pH 4.6, at a linear flow velocity of 5.2 cm/min at 50 degrees C. The method has been applied to the separation and quantitative determination of 14C-labeled 6-mercaptopurine metabolites in HClO4 extracts of L5178Y murine lymphoma cells. Distribution patterns of 14C radioactivity within the cells after a 24 h incubation period with (8-14C)-labeled 6-mercaptopurine have been established. The indentification of 6-mercaptopurine metabolites, such as 6-thioxanthosine ribonucleotide, 6-thioinosinic acid, 6-thioguanylic acid, 6-methylthioinosinic acid, and 6-thiouric acid, after the digestion of the extracts with alkaline phosphatase has been confirmed using the behaviour of each compound in enzymatic peak-shifting analyses with purine nucleoside phosphorylase and the corresponding elution volumes of 6-thiopurine bases and ribonucleosides as proofs. According to the specific radioactivity of the (8-14C)-labeled 6-mercaptopurine batch, the amounts of the various 6-mercaptopurine metabolites in about 6% of the total HClO4 extract of 1.6 . 10(8) labeled cells have quantitatively been determined as 1--130 pmol. The intracellular concentration of 6-thiopurines was determined at 1.4 . 10(-5)mol/1.

Alkaline Phosphatase↗

PubMed1979

Uptake of 67Ga-6-mercaptopurines in Morris hepatoma-3924 A.

67Ga-chloro-6-mercaptopurine and 67Ga-citrato-6-mercaptopurine complexes have been prepared and their distribution in Morris-hepatoma-3924 A-bearing rats studied. The tumour affinity of the gallium-67 compounds varies in the order: 67Ga-chloro-6-mercaptopurine greater than 67Ga-citrato-6-mercaptopurine greater than 67Ga-citrate greater than 67Ga-chloride.

Animals↗

PubMed1978

The effects on polymorphonuclear leucocyte function of prednisolone and azathioprine in vivo and prednisolone, azathioprine and 6-mercaptopurine in vitro.

The effects of prednisolone azathioprine and 6-mercaptopurine on polymorphonuclear neutrophil chemotaxis, phagocytosis, and killing of Staphylococcus aureus and Candida albicans have been studied. In twenty patients with a functioning kidney graft, taking both azathioprine 2.5 mg/kg/day and prednisolone (mean dose 0.59 mg/kg/day; range 0.30-1.0 mg/kg/day), the polymorphonuclear function did not significantly differ from that in either twenty-two normal or eighteen uraemic controls. Addition of prednisolone, 1.2 X 10(-5) M, azathioprine, 2.1 X 10(-5) M, and 6-mercaptopurine, 2.1 X 10(-5) M, using each drug alone, to normal human polymorphonuclear cells in vitro did not significantly alter their function. It is concluded that prednisolone and azathioprine together in vivo and that both these drugs and 6-mercaptopurine singly in vitro have no significant deleterious effect on polymorphonuclear function and do not contribute, in this way, to the increased susceptibility of patients receiving these drugs to infection.

Adolescent↗

PubMed1975

Combination effect of bis(3-methylsulfonyloxypropyl)amide and 6-mercaptopurine on AH-60C and AH-109A.

Survival period of rats bearing ascites hepatoma, AH-60C, which was less sensitive to bis (3-methylsulfonyloxypropyl)amine (864-T) and 6-mercaptopurine each alone, was prolonged by the combined treatment with these two agents. Two or 3 rats in groups of 12 animals each survived over 60 days by this combined therapy beginning from day 0. In AH-109A, which was insensitive to 6-mercaptopurine, the group treated with this combination did not survive longer than that with 864-T alone.

Animals↗

PubMed1977

[Modification of immune reactions by antigen-immunosuppressive agent conjugates. V. Studies on antigen-specific activity of 6-mercaptopurine bovine gamma globulin conjugates on the humoral immune response in rabbits].

Rabbits treated daily and for seven consecutive days with 6-mercaptopurine bovine gamma globulin conjugates (MPI--n-BGG; 'I'--characterizes the king of chemical binding and 'n' the number of coupled MP-residues per one mole BGG) show an altered immunological reactivity. A following intradermal immunization with BGG alum adsorbate results in a suppressed anti BGG antibody production on the third day after antigen application (antibody titer 1:320, antibody titer of control animals--pretreated with BGG and uncoupled 6-MP equals 1:5120). Already three days later the antibody titers of the test groups show a significant increase and are two dilution stages higher than the titers of the controls. A suppressive effect on the third day is induced by MPI--13-BGG, MPI--26-BGG, MPI--36-BGG and MPI--46-BGG; the later adjuvant effect can only be seen in the MPI--26-BGG, MPI--36-BGG and MPI--46-BGG but not in the MPI--13-BGG pretreated animal group. While the short time suppression was antigen specific--the humoral immune response against a second unrelated antigen was not reduced--the adjuvans effect was not antigen specific. A pretreatment with the substances mentioned above results in an increased anti BGG and anti HSA serum antibody level. Comparing investigations on the unspecific immunosuppression in rabbits by 6-mercaptopurine shows that application of 10 mg 6-MP/kg/day for seven days at first leads to a suppression but later on to an enhancement of antibody production. Application of 10 mg 6-MP/kg/day for 10 days results in a long lasting suppression without enhancement effect. As a reason for these differences the different catabolism of immunosuppressive agent and antigen is discussed. For the phenomena following antigen specific immunosuppression, similar mechanisms can be responsible.

Agglutination↗

PubMed1978

[Induction of immune tolerance to protein antigens in mice by 6-mercaptopurine (author's transl)].

The tolerance induction in mice to human serum albumin (HSA) and bovine gamma globulin (BGG) by combined injections of antigen and 6-mercaptopurine is studied. After pretreatment with antigen and mercaptopurine specific unresponsiveness or hyporesponsiveness are observed both in inbred (CBA) and outbred mice. Under the experimental protocol HSA is more tolerogenic than BGG. In CBA-mice tolerance to BGG was only found on the level of IgG-antibodies. The factors which influence the development of a drug-induced immunological unresponsiveness (mice strain, quality of antigen and antigen dosage) and the role of test system are discussed.

Animals↗

PubMed1977

Effects of cytosine arabinoside, 6-aminonicotinamide, and 6-mercaptopurine riboside on ectoderm and mesoderm of mouse limb buds.

The effects of cytosine arabinoside, 6-aminonicotinamide, and 6-mercaptopurine riboside on the incorporation of [14C] glucose moieties and [32P] phosphate into acid-soluble material and lipids, RNA, DNA, and protein were measured in the dissected mesoderm and ectoderm of mouse limb buds at the 42-45 (day 11) somite stage. Due to the different proliferative capacities of the two tissues the incorporation of the precursors into mesodermal cells was considerably higher the than into ectodermal ones. Cytosine arabinoside inhibited the incorporation of the precursor moieties only into DNA, but very early after its application. This effect was more obvious in mesoderm than ectoderm. 6-Aminonicotinamide interfered only with glucose metabolism, whereas the incorporation of phosphate was not affected. 14C radioactivity in the various cell components was similarly reduced in mesoderm and ectoderm. 6-mercaptopurine riboside caused an increased incorporation of precursor material in all fractions studied in the mesoderm as well as in the ectoderm during the first 12 hours. This was succeeded by a dramatic decrease of incorporated 14C and 32P radioactivity. Differences of response in the tissues could not be detected with this drug. It is suggested that the malformations of the extrmities caused by these antimetabolites may be predominantly attributed to changes in the cell function rather than to gross effects on cell metabolism.

6-Aminonicotinamide↗

PubMed1979

A fluorimetric assay of the phosphoribosylation of 6-mercaptopurine in human blood cells.

A new fluorimetric method to assay HGPRT (hypoxanthine-guanine phosphoribosyl transferase, EC 2.4.2.8) from human red cell lysates using 6MP (6-mercaptopurine) as substrate is described. This assay is compared with an existing spectrophotometric method using hypoxanthine as substrate. Precision, sensitivity limits and kinetic differences of these assays are reported.

Erythrocytes↗

PubMed1979

Mechanisms in the suppression of delayed hypersensitivity in the guinea pig by 6-mercaptopurine. II: Kinetic and morphologic studies on the monocyte-macrophage component.

The effect of 6-mercaptopurine on the development and expression of delayed hypersensitivity was studied in the guinea pig. Results indicated that 6-MP produced its suppressive effects primarily by action on cells of the monocyte-macrophage series. Suppression could occur under conditions of both developing and pre-established delayed hypersensitivity. The defect primarily involved newly synthesized, bone marrow-derived monocytes. Marked alterations in monocyte macrophage generation and distribution, especially the T1/2 of circulating monocytes were demonstrated. Suppressive effects were associated with the appearance of a unique morphologic microscopy. Finally, the in vivo expression of delayed hypersensitivity correlated better with a variety of parameters relating to qualitative macrophage function and distribution rather than those relating to quantitative macrophage levels.

Animals↗

PubMed1978

Specific and sensitive combined high-performance liquid chromatographic-flow fluorometric assay for intracellular 6-thioguanine nucleotides metabolites of 6-mercaptopurine and 6-thioguanine.

A new non-radioisotopic technique is described for measuring rates of intracellular formation by human leukemic blasts of 6-thioguanine nucleotide metabolites, obligatory intermediates in the antineoplastic action of both 6-mercaptopurine and 6-thioguanine itself. The method is both specific and sensitive, and involves combined high-performance liquid chromatography and flow fluormetric detection of oxidized 6-thioquanine nucleotides in alkaline permanganate-treated cell extracts. Non-metabolized 6-thioguanine and 6-thioxanthine are also separated and quantitated in this system, permitting complementary in vivo pharmacokinetic analysis. The assay may be applied to detect resistant disease at an early stage in therapy, and thereby provides the opportunity for alternative treatments to be instituted.

Body Fluids↗

PubMed1979

Determination of 6-mercaptopurine and azathioprine in plasma by high-performance liquid chromatography.

Using 1-ml plasma samples, levels of 6-mercaptopurine (6MP) as low as 5 ng/ml and azathioprine (AZA) as low as 40 ng/ml can be detected using a high-performance liquid chromatography reversed-phase column procedure following extraction. Both compounds were stable in frozen plasma for seven weeks. AZA stability in blood was temperature dependent; the half-lives of AZA breakdown to 6MP at 37 degrees were 28 and 46 min in blood drawn from two rhesus monkeys. Plasma levels of 6MP were measured in a rhesus monkey following 6MP (1.47 mg/kg) and AZA (3 mg/kg) intravenous administration. 6MP levels were also measured in three renal transplant patients on daily 50- and 100-mg AZA doses. Peak levels (45-75 ng/ml) were reached within an hour and 6MP levels were detected for up to 7 h.

Animals↗

PubMed1979

Assay of azathioprine, 6-mercaptopurine and a novel thiopurine metabolite in human plasma.

1 A simple, specific assay for 6-mercaptopurine (6-MP) in human plasma with a sensitivity of 10 ng/ml (66 nmol/1) has been developed. 2 6-MP was extracted directly from plasma into toluene using a novel extraction procedure. This involves conversion of 6-MP into a phenyl mercury derivative by its reaction with phenyl mercuric acetate in alkaline plasma and extracting into toluene. Back-extraction of the toluene layer with 0.1N HCl regenerates 6-MP, which is then oxidised to purine-6-sulphonate and assayed fluorimetrically. 3 This assay has been modified to measure azathioprine and a new thiopurine metabolite in plasma. 4 In a kidney transplant patient given azathioprine, 50 mg i.v., conversion to 6-MP was rapid and the plasma half-life of 6-MP was 36 min. 5 These assays are suitable for studying the pharmacokinetics of azathioprine in patients with kidney transplants. The 6-MP assay should also prove useful for studying the pharmacokinetics of the drug in patients with leukaemia.

Azathioprine↗

PubMed1979

Developmental abnormalities induced by 6-mercaptopurine in the hamster.

Pregnant hamsters were given varying doses of 6-mercaptopurine (6MP) at various times during gestation. The fetuses were examined for both gross and histological malformations which showed that the toxic and teratogenic effects of 6MP were dose and time dependent. The most severe gross malformations induced by 6MP were cleft palate, micrognathia and agnathia, microglossia, short limbs, and gut herniation. Grossly normal appearing fetuses, greated during late gestation, showed malformations at the tissue and cellular level. The effects of 6MP in hamster was compared with other species, and with other growth-supressive agents, and it was deduced that the teratogenicity of 6MP is species and tissue specific. Also, it was recommended that histological observations be made an integral part of the teratological safety analysis.

Abnormalities, Drug-Induced↗

PubMed1978

Effect of 6-mercaptopurine on response to major and minor histocompatibility antigens.

Pregraft treatment of chicks with 6 mercaptopurine-palladium complex (6-MP-Pd) resulted in a 16% survival of skin allografts incompatible at the major histocompatibility locus B. These incompatible grafts survived beyond 16 weeks postgrafting and showed profuse feather growth. No form of postgraft treatment was necessary. All nontreated incompatible grafts were rejected prior to 4 weeks postgrafting with no evidence of feather development. The same treatment, however, did not significantly suppress rejection of B-system compatible grafts which differed at minor histocompatibility loci. The rate of feather growth in successful B-system compatible grafts was significantly enhanced by the 6-MP-Pd treatment through 2 weeks postgrafting. Though the drug appears to affect the cellular immune system, the humoral immune response was unaffected as evidenced by a high antibody titer following turkey erythrocyte challenge.

Animals↗

PubMed1976

[Resistance of a line of Djungarian hamster cells to 6-mercaptopurine].

A cell line resistant to 6-mercaptopurine (6-MP) is isolated from Djungarian hamster embryonic fibroblasts transformed with SV-40, 6-MP resistance is due to the absence or complete inhibition of GGPRT activity. Initial and resistant cell cultures are similar in the growth rate and in the inoculation efficiency. Caryological analysis (differential chromosome staining--S-bands) revealed considerable caryotype rearrangements in both resistant and sensitive lines as compared with Djungarian hamster normal chromosome set, and also the appearance of specific chromosome markers.

Animals↗

PubMed1977

Treatment of juvenile chronic myeloid leukemia with sequential subcutaneous cytarabine and oral mercaptopurine.

Three cases of the juvenile type of chronic myeloid leukemia are described, all of which have shown a clinical and hematologic response to repeated cycles of sequential subcutaneous cytarabine and oral mercaptopurine. It appears that this regime, as described, may afford some control of a disease process previously supposed to be unresponsive to chemotherapy. This control, however, is likely to be reflected in an improvement in well-being, rather than overall survival time. Patient 1 survived 26 mo from diagnosis, and patients 2 and 3 are alive and well 12 and 9 mo from diagnosis, respectively.

Administration, Oral↗

PubMed1978

Demonstration of enzymatic activity converting azathioprine to 6-mercaptopurine.

The enzymatic conversion of azathioprine to 6-mercaptopurine was detected at pH 6.5 with rat liver supernatants, although the non-enzymatic reaction predominated at pH 7.0 and 7.5. Glutathione S-transferase may catalize this conversion. Activities of the enzyme in liver with both zathioprine and 1,2-dichloro-4-nitrobenzene as substrate decreased upon carbon tetrachloride-induced hepatic injury. These results may explain an ineffectiveness of azathioprine in patients with severe hepatic damage.

Animals↗