Modified DHAP regimen in the salvage treatment of refractory or relapsed lymphomas.

BACKGROUND: The combination of dexamethasone, high-dose cytarabine, and cisplatin (DHAP) is an established salvage regimen for lymphoma patients. We hypothesized that a modified administration schedule for cisplatin and cytarabine results in lower toxicity and improved efficacy. METHODS: We retrospectively analysed 119 patients with relapsed or refractory, aggressive, or indolent B-cell lymphomas, mantle-cell lymphomas, peripheral T-cell lymphomas, or Hodgkin's lymphomas who were treated with the modified DHAP (mDHAP) regimen (dexamethasone 40 mg 15 min-i.v. infusion, days 1-4; cytarabine 2 × 0.5 g/m2 1 h-i.v. infusion, days 1-4; cisplatin 25 mg/m2 24 h-i.v. infusion, days 1-4). Responding and eligible patients underwent stem-cell transplantation. RESULTS: In total, 185 treatment cycles were evaluable. Severe myelosuppression was the main toxicity occurring in 90% of the cycles. Febrile neutropenia or documented infection was found in less than 40%. Two patients died related to treatment (TRM, 1.7%). Nephrotoxicity did not exceed CTC grade 3, which occurred in four cycles only (2.2%). Complete (CR) or partial (PR) responses after mDHAP were documented in 16% and 39% (overall response rate 55%). Harvest of autologous stem cells was successful in 94 (79%) patients and 85 patients (71%) proceeded to stem-cell transplantation. The median overall and progression-free survival was 50.8 and 25.8 months. CONCLUSIONS: An improvement in efficacy could not be observed after modified DHAP regimen; however, manageable toxicity and reduced renal complications suggest further investigation. The study, however, also underlines the need for new concepts in the management of advanced and high-risk lymphomas.

Diversity of meiofauna from the 9°50'N East Pacific rise across a gradient of hydrothermal fluid emissions.

BACKGROUND: We studied the meiofauna community at deep-sea hydrothermal vents along a gradient of vent fluid emissions in the axial summit trought (AST) of the East Pacific Rise 9°50'N region. The gradient ranged from extreme high temperatures, high sulfide concentrations, and low pH at sulfide chimneys to ambient deep-sea water conditions on bare basalt. We explore meiofauna diversity and abundance, and discuss its possible underlying ecological and evolutionary processes. METHODOLOGY/PRINCIPAL FINDINGS: After sampling in five physico-chemically different habitats, the meiofauna was sorted, counted and classified. Abundances were low at all sites. A total of 52 species were identified at vent habitats. The vent community was dominated by hard substrate generalists that also lived on bare basalt at ambient deep-sea temperature in the axial summit trough (AST generalists). Some vent species were restricted to a specific vent habitat (vent specialists), but others occurred over a wide range of physico-chemical conditions (vent generalists). Additionally, 35 species were only found on cold bare basalt (basalt specialists). At vent sites, species richness and diversity clearly increased with decreasing influence of vent fluid emissions from extreme flow sulfide chimney (no fauna), high flow pompei worm (S: 4-7, H'(loge): 0.11-0.45), vigorous flow tubeworm (S: 8-23; H'(loge): 0.44-2.00) to low flow mussel habitats (S: 28-31; H'(loge): 2.34-2.60). CONCLUSIONS/SIGNIFICANCE: Our data suggest that with increasing temperature and toxic hydrogen sulfide concentrations and increasing amplitude of variation of these factors, fewer species are able to cope with these extreme conditions. This results in less diverse communities in more extreme habitats. The finding of many species being present at sites with and without vent fluid emissions points to a non endemic deep-sea hydrothermal vent meiofaunal community. This is in contrast to a mostly endemic macrofauna but similar to what is known for meiofauna from shallow-water vents.