The efficacy of intravenous administration of 400 mg carboplatin/m 2 body surface area over 60 minutes combined with hyperbaric oxygenation (HBO) therapy (0.2 MPa for 60 min) was investigated in 6 Japanese patients (aged 36-67 years) with malignant or brainstem gliomas. Plasma ultra-filtrate samples were analyzed by high-performance liquid chromatography to evaluate the relationship between efficacy and pharmacokinetics. Brain tumor response was evaluated by magnetic resonance imaging as a function of maximum plasma concentration, area under the curve, or mean residence time (MRT) for carboplatin. The MRT for carboplatin in the complete or partial response group (mean ± standard deviation 4.3 ± 1.7 hrs; 6 courses in 3 patients) was significantly longer (p º 0.05) than that in the progressive disease group (2.4 ± 0.1 hrs; 3 courses in 3 patients), but maximum plasma concentration and area under the curve showed no differences. These results suggest that HBO therapy prolongs the biological residence time of carboplatin. MRT for carboplatin may be useful for predicting continuation or modification of chemotherapy and/or clinical antitumor effects in patients with malignant gliomas.

Background Linezolid is a new oxazolidinone antibiotic used for infections caused by methicillin-resistant Staphylococcus and other species. Case presentation Two cases of knee osteoarthritis with acute infection were successfully treated using linezolid. The plasma and synovial fluid concentrations of linezolid in two patients [women aged 69 and 73 years (cases 1 and 2)] with knee osteoarthritis infected with Staphylococcus aureus were measured after they were administered 600 mg twice daily by intravenous infusion. The plasma linezolid concentrations during knee surgery in case 1 at day 5 and in case 2 at day 2 were 19.6 and 15.6 μg/mL, respectively. The synovial fluid concentrations of linezolid in samples taken during surgery in case 1 and case 2 were 14.9 and 17.0 μg/mL, respectively; these values corresponded to ratios of synovial fluid/plasma of 76 and 109%. Possible metabolite 2-hydroxylated linezolid potentially mediated by cytochrome P450 2 J2 was not detected in the plasma or synovial fluid samples under the current clinical setting after multiple doses. Conclusions These results implied nearly equivalent concentrations of linezolid in plasma and synovial fluid of clinical patients with knee osteoarthritis acutely infected with Staphylococcus aureus.