BackgroundIncreasing environmental and occupational exposures to nanoparticles (NPs) warrant deeper insight into the toxicological mechanisms induced by these materials. The present study was designed to characterize the cell death induced by carbon black (CB) and titanium dioxide (TiO2) NPs in bronchial epithelial cells (16HBE14o- cell line and primary cells) and to investigate the implicated molecular pathways.ResultsDetailed time course studies revealed that both CB (13 nm) and TiO2(15 nm) NP exposed cells exhibit typical morphological (decreased cell size, membrane blebbing, peripheral chromatin condensation, apoptotic body formation) and biochemical (caspase activation and DNA fragmentation) features of apoptotic cell death. A decrease in mitochondrial membrane potential, activation of Bax and release of cytochrome c from mitochondria were only observed in case of CB NPs whereas lipid peroxidation, lysosomal membrane destabilization and cathepsin B release were observed during the apoptotic process induced by TiO2 NPs. Furthermore, ROS production was observed after exposure to CB and TiO2 but hydrogen peroxide (H2O2) production was only involved in apoptosis induction by CB NPs.ConclusionsBoth CB and TiO2 NPs induce apoptotic cell death in bronchial epithelial cells. CB NPs induce apoptosis by a ROS dependent mitochondrial pathway whereas TiO2 NPs induce cell death through lysosomal membrane destabilization and lipid peroxidation. Although the final outcome is similar (apoptosis), the molecular pathways activated by NPs differ depending upon the chemical nature of the NPs.

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It has been suggested that the inappropriate sequestration of weak-base chemotherapeutic drugs in acidic vesicles by multidrug-resistance (MDR) cells contributes to the mechanisms of drug resistance. The function of the acidic lysosomes can be altered in MDR cells, and so we investigated the effects of lysosomotropic agents on the secretion of lysosomal enzymes and on the intracellular distribution of the weak-base anthracycline daunomycin in drug-resistant renal proximal tubule PKSV-PR(col50) cells and their drug-sensitive PKSV-PR cell counterparts. Imaging studies using pH-dependent lysosomotropic dyes revealed that drug-sensitive and drug-resistant cells exhibited a similar acidic lysosomal pH (around 5.6-5.7), but that PKSV-PR(col50) cells contained more acidic lysosomes and secreted more of the lysosomal enzymes N -acetyl-beta-hexosaminidase and beta-glucuronidase than their parent PKSV-PR cells. Concanamycin A (CCM A), a potent inhibitor of the vacuolar H(+)-ATPase, but not the P-glycoprotein modulator verapamil, stimulated the secretion of N -acetyl-beta-hexosaminidase in both drug-sensitive and drug-resistant cells. Fluorescent studies and Percoll density gradient fractionation studies revealed that daunomycin accumulated predominantly in the lysosomes of PKSV-PR(col50) cells, whereas in PKSV-PR cells the drug was distributed evenly throughout the nucleo-cytoplasmic compartments. CCM A did not impair the cellular efflux of daunomycin, but induced the rapid nucleo-cytoplasmic redistribution of the drug in PKSV-PR(col50) cells. In addition, CCM A and bafilomycin A1 almost completely restored the sensitivity of these drug-resistant cells to daunomycin, doxorubicin and epirubicin. These findings indicate that lysosomotropic agents that impair the acidic-pH-dependent accumulation of weak-base chemotherapeutic drugs may reverse anthracycline resistance in MDR cells with an expanded acidic lysosomal compartment.

Pulmonary veno-occlusive disease is a very rare pulmonary vascular disease and has not previously been described after bone marrow transplantation. We report the case of a 12 year old boy who developed pulmonary veno-occlusived isease after bone marrow transplantation for acute lymphoblastic leukaemia.Case report A 7 year old white boy who had previously been healthy was admitted to hospital in 1978 with acute lymphoblastic leukaemia. Complete remission was obtained with vincristine (2 mg), cyclophosphamide (600 mg), daunorubicin (35 mg daily on days 1, 2, and 3) and cytarabine (70 mg daily on days 1, 2, and 3). Maintenance treatment was continued.Five years later (1983) he suffered a relapse: a second complete remission was obtained with four injections of vincristine (2-5 mg) and prednisone. Appreciable hypercalcaemia of 4-6 mmoVl (180 mg/l) was observed; it was reduced with mithramycin, and disappeared during remission.Five months later a second relapse occurred, also associated with hypercalcaemia of 3-5 mmol/l (140 mg/l). A course of chemotherapy with vincristine (2.5 mg), prednisone, cyclophosphamide (700 mg), and daunorubicin (40 mg) was started. Complete remission could not be achieved, and it was decided to perform a marrow transplant, although 15% blast cells were observed in the bone marrow. The hypercalcaemia was again reduced with mithramycin. Until this time there had been no signs of respiratory disease and the chest radiographs had been normal throughout.An allograft was performed with engraftment from his sister, who had homologous leucocytic antibodies, after conventional preparation with combination of cyclophosphamide (60 mg/kg on days 5 and 4) and total body irradiation of 10 Gy (1000 rad) with pulmonary shielding above 8 Gy (800 rad). Methotrexate was given on days 1 (20 mg), 3 (13 mg), and 6 (13 mg) as prophylaxis against graft versus host disease but prednisone (1 mg/kg) was required on day 18 for grade 1 graft versus host disease. The transplanted marrow engrafted on day 22. Bacterial pneumonia (Pseudomonas aeroginosa) developed in the left lower lobe on day 32 and resolved incompletely with cefsulodin (3 g daily for 10 days).On day 40 he complained of abdominal pain and examination showed peripheral oedema, ascites, and hepatosplenomegaly. The conjugated bilirubin concentration was 76 (normal <8) ,umol/l (444 (normal <46.8) mg/100 ml), alkaline phosphatase activity 158 (normal <200) IU/l, serum aspartate aminotransferase activity 64 (normal <18) IU/l, and serum glutamic pyruvate transaminase activity 120 (normal <25) IU/l.On day 44 interstitial pneumonitis, predominantly affecting the right lung, developed. No cardiac abnormalities were observed on the chest radiograph or electrocardiogram. Bronchoalveolar lavage performed in the right pyramidal segment showed numerous siderophages. His respiratory state grew worse, and he died from respiratory failure despite ventilatory help. A postmortem "biopsy" of the right lower lobe was performed within an hour after death. A full necropsy was no...

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