KCa3.1-dependent uptake of the cytotoxic DNA-binding dye Hoechst 33258 into cancerous but not healthy cervical cells

The poor and nonselective penetration of current chemotherapeutics across the plasma membranes of cancer cells, which is necessary for the targeted disruption of the intracellular machinery, remains a major pharmaceutical challenge. In several cell types, including mast cells and macrophages, exposure to extracellular ATP is known to stimulate passive entry of large and otherwise membrane impermeable cationic dyes, which is usually attributed to conduction through ionotropic P2X receptors. Here, we report that elevations in cytosolic Ca2+ stimulate the rapid uptake and nuclear accumulation of a DNA-binding fluorescent cation, Hoechst 33258 (H33258), in cervical cancer cells. The H33258 uptake was dependent on activation of intermediate conductance Ca2+-activated K+ channels (KCa3.1), and direct stimulation of the channel with the activators SKA 31 and DCEBIO was sufficient to induce cellular uptake of H33258 directly. In contrast to the results from cancerous cervical cells, KCa3.1-dependent H33258 uptake was rarely observed in epithelial cells derived from the ectocervix and transformation zone of healthy cervical tissue. Furthermore, whole-cell patch clamp experiments and assessment of membrane potential using the slow voltage-sensitive dye bis-(1,3-diethylthiobarbituric acid)trimethine oxonol revealed a significant difference in functional KCa3.1 activity between cancerous and healthy cervical epithelial cells, which correlated strongly with the incidence of KCa3.1-dependent H33258 uptake. Finally, we show that activation of KCa3.1 channels caused a modest but significant sensitization of cancer cells to the growth suppressant effects of H33258, lending plausibility to the idea of using KCa3.1 channel activators to enhance cell penetration of small cationic toxins into cancer cells expressing these channels.

Drug-induced subacute cutaneous lupus erythematosus associated with nab-paclitaxel therapy

Drug-induced lupus erythematosus (dile) syndromes are documented complications of chemotherapeutic agents, including paclitaxel. Subacute cutaneous lupus erythematosus (scle) is a distinct dile syndrome presenting with characteristic annular or papulosquamous skin lesions in a photosensitive distribution with associated high anti-ssa titres. Previously, dile syndromes complicating paclitaxel therapy have been attributed to polyethoxylated castor oil (Kolliphor EL: BASF, Ludwigshafen, Germany), the biologic solvent included in the drug's original formulation (Taxol: Bristol-Myers Squibb, Montreal, QC), rather than the parent chemotherapy molecule. Here, we report a characteristic case of drug-induced scle complicating treatment with nanoparticle albumin bound (nab)-paclitaxel (Abraxane: Celgene, Summit, NJ, U.S.A.), a solvent-free taxane formulation. The pertinent English-language literature is also discussed. This case report is the first to link solvent-free paclitaxel with scle, and it suggests that the parent molecule is responsible for the reaction.

Impact of sewage sludge applications on the biogeochemistry of soils

This report describes an investigation into the bioavailability and fate of trace metals and their subsequent impact on important soil microbiological functions such as nitrification, denitrification and methane oxidation in low and high Cu containing soils in the presence and absence of residual organic matter from sewage sludge additions made 10 years earlier. The soils being studied are part of long term sewage sludge trials and include a low Cu soil (13.3 mg Cu/kg soil, 4.18 LOI %), left un-amended to serve as a control soil, soil amended with a high Cu sewage sludge (278.3 mg Cu/kg soil, 6.52 LOI %) and soil amended with a low Cu sewage sludge (46.3 mg Cu/kg soil, 6.18 LOI %). Soil was also amended with inorganic metal salts (273.4 mg Cu/kg soil, 4.52 LOI %) to further investigate the impact of Cu in the absence of additional organic matter contained in applied sewage sludge. Data from the first two years of a project are presented which has included field-based studies at long term sewage sludge trials based in Watlington, Oxford, UK and laboratory based studies at the Institute of Grassland & Environmental Research, North Wyke, Devon, UK.

Incidence of bacterial meningitis in Asia using enhanced CSF testing: polymerase chain reaction, latex agglutination and culture

To enhance the detection of bacterial meningitis in an East Asian surveillance study, we employed cerebrospinal fluid (CSF) bacterial culture, latex agglutination (LA) and polymerase chain reaction-enzyme immunoassay (PCR-EIA) testing for Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae (Sp). The sensitivity and specificity of CSF PCR-EIA testing was compared to LA and culture. A meningitis case was defined by one positive result for any of the three tests. The sensitivity of H. influenzae CSF PCR-EIA, LA, and culture was 100%, 40% and 57.5% respectively; and for Sp CSF PCR-EIA, LA and culture, the sensitivity was 100%, 58.3% and 66.7%, respectively. Hib and Sp specificity was 100% by each method. CSF PCR-EIA was more sensitive than culture or LA for the detection of Hib and Sp meningitis cases increasing their incidence by 74% and 50% compared to culture respectively. CSF PCR-EIA should be included for the detection of bacterial meningitis in surveillance studies.