Striking differences exist in outcomes for cancer between developed countries with comparable healthcare systems. We compare the healthcare systems of 3 countries (Denmark, Norway, Sweden), 3 UK jurisdictions (England, Wales and Northern Ireland), 3 Canadian provinces (British Columbia, Manitoba, Ontario) and 2 Australian states (New South Wales, Victoria) using a framework which assesses the possible contribution of primary care systems to a range of health outcomes, drawing on key characteristics influencing population health.For many of the characteristics we investigated there are no significant differences between those countries with poorer cancer outcomes (England and Denmark) and the rest. In particular, regulation, financing, the existence of patient lists, the GP gatekeeping role, direct access to secondary care, the degree of comprehensiveness of primary care services, the level of cost sharing and the type of primary care providers within healthcare systems were not specifically and consistently associated with differences between countries. Factors that could have an influence on patient and professional behaviour, and consequently contribute to delays in cancer diagnosis and poorer cancer outcomes in some countries, include centralisation of services, free movement of patients between primary care providers, access to secondary care, and the existence of patient list systems.It was not possible to establish a causal correlation between healthcare system characteristics and cancer outcomes. Further studies should explore in greater depth the associations between single health system factors and cancer outcomes, recognising that in complex systems where context is all-important, it will be difficult to establish causal relationships. Better understanding of the interaction between healthcare system variables and patient and professional behaviour may generate new hypotheses for further research.

We originally proposed that the subcellular target for one class of photosensitizing agents was the mitochondrion. This classification was based on effects that occur within minutes of irradiation of photosensitized cells: rapid loss of the mitochondrial membrane potential (delta psi m), release of cytochrome c into the cytosol and activation of caspase-3. These effects were followed by the appearance of an apoptotic morphology within 30-90 min. Fluorescence localization studies on three sensitizers initially classified as 'mitochondrial' revealed that these agents bind to a variety of intracellular membranes. The earliest detectable effect of photodamage is the selective loss of the antiapoptotic protein bcl-2 leaving the proapoptotic protein bax undamaged. Bcl-2 photodamage can be detected directly after irradiation of cells at 10 degrees C. Subsequent warming of cultures to 37 degrees C results in loss of delta psi m, release of cytochrome c and activation of caspase-3. The latter appears to amplify the other two effects. Based on results reported here we propose that the apoptotic response to these photosensitizers is derived from selective photodamage to the antiapoptotic protein bcl-2 while leaving the proapoptotic protein bax unaffected.

The photosensitizer 9-capronyloxytetrakis (methoxyethyl) porphycene localizes predominantly in the endoplasmic reticulum (ER) and, to a lesser extent, in mitochondria of murine leukemia L1210 cells. Subsequent irradiation results in the loss of ER 4 mitochondrial Bcl-2 and an apoptotic response. Although an increase in cytosolic Ca 2 þ was observed after irradiation, apoptosis was not inhibited by either the presence of the calcium chelator BAPTA or by the mitochondrial uniporter inhibitor ruthenium amino binuclear complex (Ru360). Moreover, neither reagent prevented the loss of Bcl-2. Ruthenium red (RR) devoid of Ru360 prevented Bcl-2 loss, release of Ca 2 þ from the ER and the initiation of apoptosis. Since RR was significantly more sensitive than Ru360 to oxidation by singlet oxygen, we attribute the protective effect of RR to the quenching of reactive oxygen species. Although cytosolic and (to a lesser extent) mitochondrial Ca 2 þ levels were elevated after photodynamic therapy, these changes were apparently insufficient to contribute to the development of apoptosis. Abbreviations: AM, acetoxymethyl ester; BAPTA-AM, (acetyoxymethyl)-1,2-bis(o-amino phenoxy)ethane N,N,N 0 ,N 0 -tetra (acetoxymethyl)ester; CPO, 9-capronyloxytetrakis (methoxyethyl) porphycene; DCF, 2 0 ,7 0 -dichlorofluorescein; DEVD-R110, asp-glu-val-asp-rhodamine 110; ER, endoplasmic reticulum; ERTr, endoplasmic reticulum tracker; FHS, Fischer's medium with 20 mM HEPES buffer pH 7.2 replacing NaHCO 3 ; H 2 DCF, dichlorohydrofluorescein; H 2 DCFDA, dichlorodihydrofluorescein diacetate; LTB, lysotracker blue; NAO, nonyl acridine orange; NPe6, N-aspartyl chlorin e6; PDT, photodynamic therapy; ROS, reactive oxygen species; RR, ruthenium red; Ru360, ruthenium amino binuclear complex; SnET2, tin etiopurpurin; THP, thapsigargin; TMRM, tetramethylrhodamine methyl ester; Trolox, 6-Hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (water-soluble derivative of Vitamin E); DC m , mitochondrial membrane potential

We originally proposed that the subcellular target for one class of photosensitizing agents was the mitochondrion. This classification was based on effects that occur within minutes of irradiation of photosensitized cells: rapid loss of the mitochondrial membrane potential (⌬⌿ m ), release of cytochrome c into the cytosol and activation of caspase-3. These effects were followed by the appearance of an apoptotic morphology within 30-90 min. Fluorescence localization studies on three sensitizers initially classified as 'mitochondrial' revealed that these agents bind to a variety of intracellular membranes. The earliest detectable effect of photodamage is the selective loss of the antiapoptotic protein bcl-2 leaving the proapoptotic protein bax undamaged. Bcl-2 photodamage can be detected directly after irradiation of cells at 10؇C. Subsequent warming of cultures to 37؇C results in loss of ⌬⌿ m , release of cytochrome c and activation of caspase-3. The latter appears to amplify the other two effects. Based on results reported here we propose that the apoptotic response to these photosensitizers is derived from selective photodamage to the antiapoptotic protein bcl-2 while leaving the proapoptotic protein bax unaffected.

Ursodeoxycholic acid (UDCA), a relatively nontoxic bile acid, enhanced the apoptotic response of tumor cells to both photosensitizers that cause photodamage to Bcl-2 and to the nonpeptidic Bcl-2/Bcl-x L antagonist HA14-1. The latter agent binds to the surface pocket formed by the BH1, BH2 and BH3 domains of Bcl-2 and Bcl-x L . Fluorescence polarization studies indicated that affinity of HA14-1 for Bcl-2 was enhanced in the presence of UDCA. Moreover, Bcl-2 photodamage was promoted by UDCA using a photosensitizing agent with affinity for the endoplasmic reticulum, a site of Bcl-2 localization. Fluorescence resonance energy transfer (FRET) studies revealed that the proximity of Bcl-2 to a hydrophobic photosensitizing agent embedded in liposomes was enhanced by UDCA. Since photodamage will occur only if a protein is in close contact with a photosensitizing agent, we propose that these findings support the hypothesis that UDCA causes a conformational change in Bcl-2, promoting HA14-1 binding and enhancing affinity for certain membrane-bound photosensitizers. Cell Death and Differentiation (2004) 11, 906-914. doi:10.1038/sj.cdd.4401433 Keywords: apoptosis; Bcl-2; CPO; NPe6; SnET2; photodynamic therapy (PDT)Abbreviations: CPO, 9-capronyloxy-tetrakis(methoxyethyl) porphycene; DCA, deoxycholic acid; DEVD-R110, asp-glu-valasp-rhodamine 110 (fluorogenic caspase-3 substrate); ER, endoplasmic reticulum; flu-Bak, 5-carboxyfluorecein coupled to the N terminus of a peptide GQVGRQLAIIGDDINR derived from the BH3 domain of Bak; HA14-1, ethyl 2-amino-6-bromo-4-(1-cyano-2-ethoxy-2-oxoethyl)-4H-chromene-3-carboxylate; HO342, Höchst dye HO33342; mTHPC, meta-(tetrahydroxyphenyl) chlorin; NPe6, N-aspartyl chlorin e6; P, fluorescence polarization value; PDT, photodynamic therapy; SnET2, tin etiopurpurin; UDCA, ursodeoxycholic acid.