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Progressive multifocal leukoencephalopathy (PML) is a severe demyelinating disease of the central nervous system caused by the reactivation of the John Cunningham virus (JCV) [1]. PML is commonly o...

Primary testicular lymphoma (PTL) is a rare but aggressive disease. Although most patients present in the early stage, their prognosis is poor. Similar with PTL, cardiac lymphoma is also an uncommon disease characterized by its aggressive clinical course and poor prognosis. We herein report an extremely rare case of advanced stage PTL with cardiac involvement, treated by high-dose chemotherapy with autologous stem cell transplantation (HDT-ASCT) followed by systemic chemotherapy, prophylactic intrathecal methotrexate (IT-MTX), and radiotherapy. A 48-year-old man presented with painless left scrotal swelling. He was diagnosed with PTL after orchiectomy, and the histological type was diffuse large B-cell lymphoma. For staging of lymphoma, positron emission tomography was performed, which revealed uptake in the right atrium and early cardiac metastasis within just 2 months after orchiectomy. He underwent 6 cycles of systemic chemotherapy that consisted of rituximab, doxorubicin, cyclophosphamide, vincristine, and prednisolone (R-CHOP). He also received central nervous system prophylaxis 4 times with weekly IT-MTX during the first 2 cycles of R-CHOP. He achieved complete response after 6 cycles of R-CHOP, and underwent HDT-ASCT and radiotherapy as consolidation therapy without irreversible adverse effects. He is currently doing well, with a progression-free survival of 31 months. The above treatment strategy including HDT-ASCT may be one of the treatment options for advanced stage PTL with cardiac metastasis in patients younger than 65 years old.

Incorporation of the anticancer drug fludarabine (9-beta-D-arabinofuranosyl-2-fluoroadenine 5'-monophosphate; F-ara-AMP) into the 3'-end of DNA during replication causes termination of DNA strand elongation and is strongly correlated with loss of clonogenicity. Because the proofreading mechanisms that remove 3'-F-ara-AMP from DNA represent a possible means of resistance to the drug, the present study investigated the excision of incorporated F-ara-AMP from DNA by the 3' --> 5'-exonuclease activity of DNA polymerase epsilon from human leukemia CEM cells. Using the drug-containing and normal deoxynucleotide oligomers (21-base) annealed to M13mp18(+) DNA as the excision substrates, we demonstrated that DNA polymerase epsilon was unable to effectively remove F-ara-AMP from the 3'-end of the oligomer. However, 3'-terminal dAMP and subsequently other deoxynucleotides were readily excised from DNA in a distributive fashion. Kinetic evaluation demonstrated that although DNA polymerase epsilon has a higher affinity for F-ara-AMP-terminated DNA (Km = 7.1 pM) than for dAMP-terminated DNA of otherwise identical sequence (Km = 265 pM), excision of F-ara-AMP proceeded at a substantially slower rate (Vmax = 0.053 pmol/min/mg) than for 3'-terminal dAMP (Vmax = 1.96 pmol/min/mg). When the 3'-5' phosphodiester bond between F-ara-AMP at the 3'-terminus and the adjacent normal deoxynucleotide was cleaved by DNA polymerase epsilon, the reaction products appeared to remain associated with the enzyme but without the formation of a covalent bond. No further excision of the remaining oligomers was observed after the addition of fresh DNA polymerase epsilon to the reaction. Furthermore, the addition of DNA polymerase alpha and deoxynucleoside triphosphates to the excision reaction failed to extend the oligomers. After DNA polymerase epsilon had been incubated with 3'-F-ara-AMP-21-mer for 10 min, the enzyme was no longer able to excise 3'-terminal dAMP from a freshly added normal 21-mer annealed to M13mp18(+) template. We conclude that the 3' --> 5' exonuclease of human DNA polymerase epsilon can remove 3'-terminal F-ara-AMP from DNA with difficulty and that this excision results in a mechanism-mediated formation of "dead end complex."

Idarubicin (IDA) is one of the key drugs for treating hematological malignancies. Severe myelosuppression is one of the major adverse events of IDA. Interestingly, when IDA is administered in 2 consecutive courses of therapy, IDA tends to exert a stronger bone marrow suppressive effect in the second course compared with the first course while other anthracyclines such as daunorubicin tend to milder suppressive effect in the second course compared with the first course (Wiernik PH et al, Blood, 1992). In order to clarify this unique characteristics, in vivo and in vitro studies regarding the pharmacokinetic behavior were performed. When RLN-B2 (a rat liver cell line) was precultured in the presence of IDA, higher carbonyl reducing enzymes (CREs) activity was observed compared with non-precultured cells, suggesting the anthracycline-reducing enzymes was induced in the cells incubated in the presence of IDA. We examined the in vivo effects of IDA administration on the induction of CREs and subsequent enhanced formation of the 13-OH metabolite, idarubicinol (IDAol) which is more active compared with IDA and has a remarkably long half-life in the blood. The rats (F344) preadministered IDA showed higher enzymatic activity than that from non-preadministered rats (p < 0.05). At 4 hours after IDA administration, the production of IDAol was facilitated in the preadministered group compared with the non preadministered group (p < 0.05). Clinically, the duration of leucopenia was compared between IDA and mitoxantrone, an CREs independent anthraquinone, in combination with enocytabine, 6-mercaptopurine and etoposide. In 2 consecutive therapy, namely remission-induction and first consolidation therapy, in 30 cases of acute myelogenous leukemias, the duration of leucopenia was substantially equal in IDA group while it was substantially shorter in consolidation therapy compared with induction therapy in mitoxantrone group. These results suggest that CREs was induced by IDA pretreatment in vitro and in vivo, resulting in increased IDAol, which could potentiate the myelosuppressive and probably antitumor effects of IDA in contrast to other anthracyclines. This unique PK/PD characteristics of pharmacokinetic self-potentiation could be important in the safe and effective use of IDA in the therapy for hematological malignancies.

ピストン・シリンダー型高圧容器内で, 固体圧力媒体を用いて, 5kb 以下の圧力の下で炭素を内熱式で加熱処理する場合, 高い温度を安定に得るためには,電力導入部と発熱体との接触を良好にするため,より高い圧力の下での加熱に比し多くの注意を払うことが必要であった。これらを中心に実験上の種々の問題を検討した。その結果,5kb下では1900℃ までの加熱が可能となった。3kb下では,人造黒鉛発熱体の周囲にBNをおき,パイロフィライトと人造黒鉛の反応を防ぐことにより,1750℃ までの加熱が可能となった。加圧加熱処理試料の(004)回折線図形を測定し,その解析を行なった。また複合(002)および(004)回折線図形より,成分G の割合を求める場合, 結晶子の選択的配向について, 便宜的な方法で補正を行なった。この結果は先に報告した(002) 回折線図形より求めたものとよい一致を示し, Gs 成分の割合, 各成分図形のc 軸長c0 のより精度の高い値を得ることができた。

A number of human myeloid leukemia cell lines have been established which can not only be maintained as immature blast cells in continuous, self-renewing culture but also be induced to undergo maturation toward either the myeloid or monocytic phenotype1). Such cell lines have attracted considerable attention in these days because they provide experimentally accessible model systems with which to define basic mechanisms involved in the regulation of myeloid progenitor cell proliferation and differentiation. The HL60 cell line, originally isolated from a patient with acute promyelocytic leukemia, can be lead to myeloid morphological, functional, and biochemical changes have been observed during DMSO-induced differentiation2). In differentiated HL60 cells, purine nucleotide synthesis decreases3), but there have been some reports demonstrating a drastic change in purine nucleotides pool during differentiation4–6). This seem to the presence of a complicated mechanism involved in differentiation. We used DMSO-treated HL60 cells to investigate the role of salvage and de novo pathway for intracellular purine nucleotide metabolism during proliferation and differentiation.

Transport and intracellular metabolism of the three fluorinated pyrimidines, FU, FUR and FUdR in normal human RBCs, L-1210, HL-60, CCRF-CEM and Hela cells were studied. The cells were suspended in HB 101 medium and incubated at 37°C in the presence of each labelled compound. At the desingated time, the cell suspension was put onto silicone oil layer (specific gravity:1.034) and centrifuged at 12,000xg in 7 sec. The radioactivity of cell pellet obtained was counted following lysis with NCS tissue solubilyzer. The acid-soluble fraction from cell pellet was applied onto silica gel TLC plate and chromatographed. The plate was cut into 0.5cm strips and their radioactivities were counted. All three compounds showed the same velocity of transport by RBCs. FUR transport velocity was, however, markedly high in case of L-1210, HL-60, CCRF-CEM cells and not in Hela cells. FU and FUdR transports remained at low level. These results showed that intracellular phosphorylation of the compound resulted in the acumulation in cells since FUR was preferentially converted to nucleotide form, while FU and FUdR were not in all cells studied. The chromatogram of FUdR treated CCRF-CEM and Hela cells revealed that the main radioactive peak coinsided with FU. It was concluded that FUR acumulated as its nucleotide form, while FUdR was mainly converted to FU in these cells.

Changes of PRPP-related enzyme activities and incorporation rates of glycine, Hx and Ad into acid soluble fraction (ASF) of HL60 cells were studied during terminal differentiation induced by incubation with 1.6% DMSO for 43 hours. Activities of HPRT, APRT, and PRPP synthetase were determined in homogenate treated with activated chacoal. H(A)PRT activities were measured based on the determination of conversion of 14C-labeled Hx (Ad) to IMP (AMP). PRPP synthetase activities were measured as follows; PRPP, which was formed by interaction of R-5-P, ATP and enzyme solution, was measured by HPRT assay system. Incorporation rates of Ad, Hx, and glycine into purine nucleotides were measured after incubation at 37 °C for 20 min in the presence of the respective 14C-labeled compound in HB101 medium. ASFs of cell pelletes, which were obtained by silicon oil procedure, were chromatographed. Radioactivities of all purine nucleotides were counted. HPRT and APRT activities increased 3.3 folds (4.69 to 15.70 nmol/min/106cells) and 1.5 folds (4.20 to 6.26) higher, respectively, but no increase in PRPP synthetase activities was shown. The incorporation of glycine decreased 2.2 folds (215 to 99 pmol/min/106 cells) lower in rate, but those of Ad and Hx showed no remarkable changes. It was concluded that the decreased rate of de novo synthesis was a major change during terminal differntiation.