Effects of purine nucleotide administration on purine nucleotide metabolism in brains of heroin-dependent rats

ABSTRACT Heroin is known to enhance catabolism and inhibit anabolism of purine nucleotides, leading to purine nucleotide deficiencies in rat brains. Here, we determined the effect of exogenous purine nucleotide administration on purine nucleotide metabolism in the brains of heroin-dependent rats. Heroin was administrated in increasing doses for 9 consecutive days to induce addiction, and the biochemical changes associated with heroin and purine nucleotide administration were compared among the treated groups. HPLC was performed to detect the absolute concentrations of purine nucleotides in the rat brain cortices. The enzymatic activities of adenosine deaminase (ADA) and xanthine oxidase (XO) in the treated rat cortices were analyzed, and qRT-PCR was performed to determine the relative expression of ADA, XO, adenine phosphoribosyl transferase (APRT), hypoxanthine-guaninephosphoribosyl transferase (HGPRT), and adenosine kinase (AK). Heroin increased the enzymatic activity of ADA and XO, and up-regulated the transcription of ADA and XO. Alternatively, heroin decreased the transcription of AK, APRT, and HGPRT in the rat cortices. Furthermore, purine nucleotide administration alleviated the effect of heroin on purine nucleotide content, activity of essential purine nucleotide metabolic enzymes, and transcript levels of these genes. Our findings therefore represent a novel, putative approach to the treatment of heroin addiction.

High frequency of fatal haemophagocytic lymphohistiocytosis syndrome in enteropathy-associated T cell lymphoma.

INTRODUCTION: Enteropathy-associated T-cell lymphoma is a rare form of T-cell lymphoma associated with a poor prognosis and the relative ineffectiveness of standard chemotherapy. The occurrence of haemophagocytic lymphohistiocytosis has been reported only once with this entity. PATIENTS AND METHODS: A retrospective study of 15 patients with enteropathy-associated T-cell lymphoma (type 1 in 12), followed-up in our units, since 1985. Two patients died before starting chemotherapy. The remaining 13 patients were treated with standard chemotherapy (n=7) and purine nucleotide analogues (n=6). RESULTS: Median follow-up was 8.7 (1-97) months. Surgery was required in 10 patients (66%) for intestinal complications (n=7) or elective small bowel resection (n=3). Survival probability was 40% and 20% at 1 and 5 years, respectively (Kaplan-Meier method). Survival was not significantly different between the two chemotherapy regimens. However, a slight decrease of febrile neutropenia was observed in the purine nucleotide analogues group (p=0.06). Haemophagocytic lymphohistiocytosis occurred in 6/15 (40%) cases. In these six patients, haemophagocytic lymphohistiocytosis was always fatal within 3 months. CONCLUSION: Enteropathy-associated T-cell lymphoma is associated with a poor outcome, independently of the chemotherapy regimens administered and frequent occurrence of haemophagocytic lymphohistiocytosis. The latter complication should be considered for urgent rescue therapy.

Risk factors for development of a second lymphoid malignancy in patients with chronic lymphocytic leukaemia.

Previous studies suggested that patients with chronic lymphocytic leukaemia (CLL) are at a three- to fivefold increased risk of developing a second lymphoproliferative disorder (LPD). This observational cohort study used the Mayo Clinic CLL Database to identify factors associated with developing a second LPD. A second LPD was identified in 26 (2.7%) of 962 CLL patients during a median follow-up of 3.3 years. Diffuse large B-cell lymphoma was the most common subtype of secondary LPD (12 of 26 cases). Patients previously treated for CLL had a trend toward higher prevalence of second LPD (4%) compared with previously untreated patients (2%; P = 0.053). More strikingly, patients treated with purine nucleoside analogues (PNA) had a significantly increased risk of subsequent second LPD (5.2%) compared with patients who had not received PNA (1.9%; P = 0.008). No statistically significant association was observed between risk of second LPD and other CLL characteristics (ZAP-70, CD38, IgV(H) mutation status or cytogenetic abnormalities). In this series, prior treatments with PNA or anthracyclines were the only significant factors associated with risk of developing a second LPD in patients with CLL. Physicians should strictly adhere to established criteria to initiate treatment for CLL patients who are not participating in clinical trials.