One-Pot Conversion of Methane to Light Olefins or Higher Hydrocarbons through H-SAPO-34-Catalyzed in Situ Halogenation.

Methane was converted to light olefins (ethene and propene) or higher hydrocarbons in a continuous flow reactor below 375 °C over H-SAPO-34 catalyst via an in situ halogenation (chlorination/bromination) protocol. The reaction conditions can be efficiently tuned toward selective monohalogenation of methane to methyl halides or their in situ oligomerization to higher hydrocarbons. The presence of C5+ hydrocarbons in the reaction products clearly indicates that by using a properly engineered catalyst under optimized reaction conditions, hydrocarbons in the gasoline range can be produced. This approach has significant potential for feasible application in natural gas refining to gasoline and materials under moderate operational conditions.

Couple oriented counselling improves male partner involvement in sexual and reproductive health of a couple: Evidence from the ANRS PRENAHTEST randomized trial.

BACKGROUND: Male partner involvement (MPI) has been recognized as a priority area to be strengthened in Prevention of Mother to Child Transmission (PMTCT) of HIV. We explored the impact of Couple Oriented Counselling (COC) in MPI in sexual and reproductive health and associated factors. METHOD: From February 2009 to October 2011, pregnant women were enrolled at their first antenatal care visit (ANC-1) and followed up until 6 months after delivery in the Mother and Child Center of the Chantal Biya Foundation within the randomized prenahtest multicentric trial. The MPI index was defined using sexual and reproductive health behaviour variables by using multiple correspondence analysis followed by mixed classification. Men were considered as highly involved if they had shared their HIV test results with their partner, had discussed on HIV or condom used, had contributed financially to ANC, had accompanied their wife to ANC or had practiced safe sex. Factors associated to MPI were investigated by the logistic model with GEE estimation approach. RESULTS: A total of 484 pregnant women were enrolled. The median age of the women was 27 years (IQR: 23-31) and 55.23% had a gestational age greater than 16 weeks at ANC-1. Among them, HIV prevalence was 11.9% (95% CI: 9.0-15.4). The median duration of the women's relationship with their partner was 84 months (IQR: 48-120). MPI index at 6 months after delivery was significantly greater in the COC group than the classical counselling group (14.8% vs 8,82%; p = 0,043; Fig 1). The partners of the women who participated in the COC were more likely to be involved during follow up than others (aOR = 1.45; 95% CI = 1.00-2.10). Partners with no incoming activity (aOR = 2.90; 95% CI = 1.96-4.29), who did not used violence within the couple (aOR = 1.70; 95% CI = 1.07-2.68), and whose partner came early for ANC-1 (aOR = 1.37; 95% CI = 1.00-1.89) were more likely to be involved than others. CONCLUSION: MPI remains low in stable couples and COC improves partner involvement. Our findings also support the need of strengthening outreach towards "stable" couples and addressing barriers. This could go a long way to improve PMTCT outcomes in Cameroon. TRIAL REGISTRATION: PRENAHTEST, NCT01494961. Registered 15 December 2011-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT01494961.

Couple-oriented prenatal HIV counseling for HIV primary prevention: an acceptability study.

BACKGROUND: A large proportion of the 2.5 million new adult HIV infections that occurred worldwide in 2007 were in stable couples. Feasible and acceptable strategies to improve HIV prevention in a conjugal context are scarce. In the preparatory phase of the ANRS 12127 Prenahtest multi-site HIV prevention trial, we assessed the acceptability of couple-oriented post-test HIV counseling (COC) and men's involvement within prenatal care services, among pregnant women, male partners and health care workers in Cameroon, Dominican Republic, Georgia and India. METHODS: Quantitative and qualitative research methods were used: direct observations of health services; in-depth interviews with women, men and health care workers; monitoring of the COC intervention and exit interviews with COC participants. RESULTS: In-depth interviews conducted with 92 key informants across the four sites indicated that men rarely participated in antenatal care (ANC) services, mainly because these are traditionally and programmatically a woman's domain. However men's involvement was reported to be acceptable and needed in order to improve ANC and HIV prevention services. COC was considered by the respondents to be a feasible and acceptable strategy to actively encourage men to participate in prenatal HIV counseling and testing and overall in reproductive health services. CONCLUSIONS: One of the keys to men's involvement within prenatal HIV counseling and testing is the better understanding of couple relationships, attitudes and communication patterns between men and women, in terms of HIV and sexual and reproductive health; this conjugal context should be taken into account in the provision of quality prenatal HIV counseling, which aims at integrated PMTCT and primary prevention of HIV.

WITHDRAWN: Corticosteroids for HELLP syndrome in pregnancy.

BACKGROUND: Hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome is a severe form of pre-eclampsia. Pre-eclampsia is a multi-system disease of pregnancy associated with an increase in blood pressure and increased perinatal and maternal morbidity and mortality. Eighty per cent of women with HELLP syndrome present before term. There are suggestions from observational studies that steroid treatment in HELLP syndrome may improve disordered maternal hematological and biochemical features and perhaps perinatal mortality and morbidity. OBJECTIVES: To summarise the evidence on the effects of corticosteroids on maternal and neonatal mortality and morbidity in women with HELLP syndrome. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group trials register (October 2003). We scanned lists of references from review articles and primary studies. SELECTION CRITERIA: Randomised and quasi-randomised trials evaluating the effects of adjunctive corticosteroids in patients diagnosed with HELLP syndrome were sought. DATA COLLECTION AND ANALYSIS: The two authors independently applied inclusion criteria, assessed trial quality and extracted relevant data. MAIN RESULTS: Of the five studies reviewed (n = 170), three were conducted antepartum and two postpartum. Four of the studies randomised participants to standard therapy or dexamethasone. One study compared dexamethasone with betamethasone. Dexamethasone versus control There were no significant differences in the primary outcomes of maternal mortality and morbidity due to placental abruption, pulmonary oedema and liver hematoma or rupture. Of the secondary maternal outcomes, there was a tendency to a greater platelet count increase over 48 hours, statistically significantly less mean number of hospital stay days (weighted mean difference (WMD) -4.50, 95% confidence interval (CI) -7.13 to -1.87), mean interval (hours) to delivery (41 +/- 15) versus (15 +/- 4.5) (p = 0.0068) in favour of women allocated to dexamethasone.There were no significant differences in perinatal mortality or morbidity due to respiratory distress syndrome, need for ventilatory support, intracerebral hemorrhage, necrotizing enterocolitis and a five minute Apgar less than seven. The mean birthweight was significantly greater in the group allocated to dexamethasone (WMD 247.00, 95% CI 65.41 to 428.59).Dexamethasone versus betamethasone There were no significant differences in all the maternal and perinatal mortality and in primary morbidity outcomes.Women randomised to dexamethasone fared significantly better for: oliguria, mean arterial pressure, mean increase in platelet count, mean increase in urinary output and liver enzyme elevations. AUTHORS' CONCLUSIONS: There is insufficient evidence to determine whether adjunctive steroid use in HELLP syndrome decreases maternal and perinatal mortality, major maternal and perinatal morbidity.

Neodymium-yttrium aluminium garnet laser destruction of nonsensitized and hematoporphyrin derivative-sensitized tumors.

The injection of hematoporphyrin derivative (5 mg/kg i.v.) followed 24 hr later by a neodymium-yttrium aluminium garnet laser irradiation shows the destruction of CX1 tumors grafted on nude mice. This acidophilic necrosis occurred with a significantly increased frequency in tumors treated by hematoporphyrin derivative injection and irradiated with the neodymium-yttrium aluminium garnet laser as compared with noninjected but irradiated tumors or with injected tumors irradiated with sunlight. On the basis of our data, it seems difficult to maintain the hypothesis of singlet oxygen production as the only mechanism of the phenomenon. Further studies will be necessary to explain the necrosis that we observed.

Crystal and mol-ecular structure of aflatrem.

The crystal structure of the title compound, C32H39NO4, confirms the absolute configuration of the seven chiral centres in the mol-ecule. The molecule has a 1,1-dimethylprop-2-enyl substituent on the indole nucleus and this nucleus shares one edge with the five-membered ring which is, in turn, connected to a sequence of three edge-shared fused rings. The skeleton is completed by the 7,7-trimethyl-6,8-dioxabi-cyclo-[3.2.1]oct-3-en-2-one group connected to the terminal cyclohexene ring. The two cyclohexane rings adopt chair and half-chair conformations, while in the dioxabi-cyclo-[3.2.1]oct-3-en-2-one unit, the six-membered ring has a half-chair conformation. The indole system of the mol-ecule exhibits a tilt of 2.02 (1)° between its two rings. In the crystal, O-H⋯O hydrogen bonds connect mol-ecules into chains along [010]. Weak N-H⋯π inter-actions connect these chains, forming sheets parallel to (10-1).

Experimental aspects of in vitro and in vivo photochemotherapy.

The selectivity of in vitro photodynamic reactions and the in vivo effects induced by PRT, whether the irradiation is applied interstitially or externally, still remains unclear. In vitro studies were performed using leukemic cell lines and syngeneic normal hemopoietic progenitors. For these, cells incubated with hematoporphyrin derivative (HPD) and non-incubated cells were irradiated with an argon laser. Data were obtained as the count of cell colonies found after a 7-day incubation period on semi-solid collagen gel medium. In vivo studies employed the HT 29 tumor model grafted into nude mice. Both animals injected with HPD and non-infected controls were irradiated with a dye laser pumped by an argon laser (Coherent) using a 400 micron optic fiber located either at a distance of 65 mm from the skin or inserted into the tumor. The temperature increase occurring during PRT was measured using non-absorbing thermocouples. In vitro, after HPD treatment and argon irradiation leukemic cells showed a greater phototoxicity (greater than 2 log10) than did the normal cells (0.25 log10). In vivo, when the heat rise is very similar (less than 4 degrees C) in both the tissues irradiated externally and those irradiated interstitially after HPD injection, histological examination of these did not reveal any quantitative differences (90% of tumor mass). These results are discussed.

Influence of hematoporphyrin derivative concentration, incubation time, temperature during incubation and laser dose fractionation on photosensitivity of normal hemopoietic progenitors or leukemic cells.

Photodynamic therapy represents a new approach for the local control of cancers. It has recently been claimed that photodynamic therapy mediated by hematoporphyrin derivative (HPD) is selectively more efficient for killing leukemic cells than normal progenitors. To improve this effect, we studied the influence of hematoporphyrin dose, temperature during incubation and/or treatment, hematoporphyrin derivative incubation time, and fractionation of the argon laser light (488-514 nm) used for hematoporphyrin stimulation. Plating efficiency calculated after a 7-day period of growth on collagen gel medium showed a dose-dependent phototoxicity of HPD reaching 0.01% for normal hemopoietic progenitors and 0.001% for leukemic cells (dose = 12.5 micrograms/ml). The 10:1 ratio of normal hemopoietic progenitors to leukemic cells was also found to be the same or increased when temperature was 37 degrees C during incubation and 4 degrees C during laser irradiation. Similar results were also found when incubation time was varied from 75-120 min, or when laser irradiation dose was fractionated into 2 or 3 periods. The ratio of normal progenitors to leukemic cells reached 100:1 when 75 J/cm2 were fractionated into 3 periods after an incubation time of 120 min with 10 micrograms/ml HPD. Selectivity in photodynamic treatment seems to occur between normal hemopoietic progenitors and leukemic cells. The mechanism of this selectivity remains unclear, but experiments with the fractionated irradiation dose suggest that as in radiotherapy, better potentially lethal damage repair in normal cells could be a factor for selectivity in photodynamic therapy. Our results obtained with leukemic cells are fully in agreement with data in the literature concerning similar experimental models.

Effects of high glucose concentration on survival and respiration of human endothelial cells.

To determine whether or not endothelial cell survival was decreased after incubation with high glucose concentrations in culture media, we studied the influence of D-glucose or L-glucose (a non-metabolizable stereoisomer of D-glucose) on cell survival using the trypan-blue exclusion test. Simultaneously, the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide) assay was used to measure both the mitochondrial respiratory chain activity and cell viability. Respiratory chain activity per cell increased when D-glucose concentrations rose but at the same time trypan-blue excluded cells were decreased. Comparison with data in the literature showed that the MTT assay was not reliable for studies involving endothelial cell survival when glucose reduction was affected on these cells. It seems important to check MTT assay reliability carefully when it is used for drugs affecting glucose metabolism, or with other cell types.

In vitro fluorescence, toxicity and phototoxicity induced by delta-aminolevulinic acid (ALA) or ALA-esters.

Synthesis of delta-aminolevulinic acid (ALA) derivatives is a promising way to improve the therapeutic properties of ALA, particularly cell uptake or homogeneity of protoporphyrin IX (PpIX) synthesis. The fluorescence emission kinetics and phototoxic properties of ALA-n-pentyl ester (E1) and R,S-ALA-2-(hydroxymethyl) tetrahydrofuranyl ester (E2) were compared with those of ALA and assessed on C6 glioma cells. ALA (100 micrograms/mL), E1 and E2 (10 micrograms/mL) induced similar PpIX-fluorescence kinetics (maximum between 5 and 7 h incubation), fluorescence being limited to the cytoplasm. The 50% lethal dose occurred after 6 h with 45, 4 and 8 micrograms/mL of ALA, E1 and E2, respectively. ALA, E1 and E2 induced no dark toxicity when drugs were removed after 5 min of incubation. However, light (25 J/cm2) applied 6 h after 5 min incubation with 168 micrograms/mL of each compound induced 85% survival with ALA, 27% with E1 and 41% with E2. Increasing the incubation time with ALA, E1 and E2 before washing increased the phototoxicity, but E1 and E2 remained more efficient than ALA, regardless of incubation time. ALA-esters were more efficient than ALA in inducing phototoxicity after short incubation times, probably through an increase of the amount of PpIX synthesized by C6 cells.

Heterogeneity of delta-aminolevulinic acid-induced protoporphyrin IX fluorescence in human glioma cells and leukemic lymphocytes.

Delta-aminolevulinic acid (ALA)-PDT efficacy is particularly dependent on the quality of protoporphyrin IX (PpIX)-induced synthesis. The purpose of this study was to determine the ability of cells from two human cancer types to synthesise PpIX after ALA administration. Biopsies of glioma cells have been obtained from patients with glioblastomas that have or have not been given ALA IV (ex vivo incubation). Peripheral blood lymphocytes, obtained from leukemic patients, have also been ALA-incubated in vitro. In glioma cells, fluorescence heterogeneity was extensive either in ALA infused patients or in ex vivo ALA incubated cells. Mean intensities after 3 h were 110 cts (range 0-340) and 1000 cts (range 0-3600). Similar results were found in leukemic lymphocytes where cell fluorescence varied from 0 to 480 cts with a percentage of fluorescent cells varying with time and from one patient to another. Furthermore, PpIX was not detectable in two patients with CLL. These observations suggest that a marked heterogeneity of ALA uptake and/or PpIX synthesis exists in a given human cancer cell population particularly after systemic administration. Improvements for ALA transformation into PpIX are strongly recommended to ensure the efficacy of ALA/PpIX-PDT.

Enhancement of delta aminolevulinic acid-photodynamic therapy in vivo by decreasing tumor pH with glucose and amiloride.

OBJECTIVES/HYPOTHESIS: Delta aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) is a fluorescent sensitizer that permits detection and treatment of squamous cell carcinoma of the oral cavity. An exogenously induced decrease in tissue pH was evaluated for its effect in enhancing cellular uptake of ALA and facilitating its transformation into PpIX. STUDY DESIGN: Mice grafted with HT29 colonic cancers had been given glucose and amiloride to modify the pH of tissues. Influence of pH changes has been evaluated on ALA-induced PPIX fluorescence by optic fiber spectrofluorimetry as well as on tumor growth. RESULTS: The pH in HT 29 tumor decreased from 7.1 to 6.67 (P < .05) after intraperitoneal injection of glucose and amiloride. The PpIX fluorescence ratios in tumor or muscle before, between, and 2 hours after glucose and amiloride injection were not higher than control ratios. Aminolevulinic acid-photodynamic therapy was more efficient on HT 29 tumor-bearing mice when the pH value was decreased with glucose and amiloride, showing a difference in the tumor growth index ratio from the 1st to 14th day of 22% between amiloride-glucose aminolevulinic acid-photodynamic therapy and aminolevulinic acid-photodynamic therapy alone (P < .05). CONCLUSIONS: Glucose and amiloride did not change PpIX fluorescence in HT 29 tumor after intraperitoneal injection of aminolevulinic acid but enhanced aminolevulinic acid-photodynamic therapy efficacy. This was probably a result of mechanisms other than an increase in aminolevulinic acid cellular penetration and PpIX production, such as susceptibility to free radical toxicity or alteration of cellular repair enzymes under acidotic conditions. If a decrease of pH induces a more efficient photodynamic therapy as suggested by our results, an easier way to obtain this decrease than glucose and amiloride would be necessary for clinical applications.

Tissue detection of diphenylchlorin sensitizer (SIM01) by fluorescence and high-performance liquid chromatography.

Cancer is today a major problem of public health. Unfortunately, the current treatments remain still too often impotent or too heavy compared to the gross national product of many countries. The use of PDT in the treatment of the malignant tumours currently raises great hopes. This physicochemical method is based on the combined action of a nontoxic drug given systematically to the patient and of the visible light delivered locally to the tumour using optical fibres. The radiation will activate the significant substance preferentially fixed on cancerous cells and will cause the death of the tumoral cells while releasing from the toxic ridicalizing species which then will deteriorate vital cellular targets. Tissue distribution and elimination kinetics of the SIM01 were analysed in biological samples from mice tissues by spectrofluorometry and HPLC. Measurements were performed 4, 6, 12, 24 and 48h after an intraperitoneal injection for SIM01 doses of 2, 5 and 15mgkg(-1). Elimination seemed to concern essentially gallbladder, liver and stools, where maximum fluorescence reached, respectively, 20,000, 2800 and 15,000cps for 5mgkg(-1), 6h after injection. Among the tissues examined with HPLC, the highest SIM01 levels were found in stools, urine, liver, gallbladder and spleen. Liver, gallbladder, and stool homogenates from drug-treated animals contained an additional peak (16, 7min) detectable only after injection of at least 15mgkg(-1). Our HPLC determinations and in vivo fluorescence detection of SIM01 gave comparable kinetic profiles. These techniques should be considered as complementary rather than exclusive for kinetic profiles determination.

Delta-aminolevulinic acid-induced fluorescence in normal human lymphocytes.

Endogenously generated protoporphyrin IX (PpIX) from exogenous delta-aminolevulinic acid (ALA) has the photodynamic capacity to inactive cancer cells of different origins. The aim of this study was to characterize the ability of normal lymphocytes to transform ALA into PpIX in order to appreciate through further studies changes in pathologic lymphocytes. We investigated in this study PpIX synthesis by normal human lymphocytes using a confocal laser microspectrofluorometer. Live lymphocytes were identified by monoclonal antibody fluorescent labeling. B and T lymphocytes synthesized PpIX (80-100 counts), with a maximum being reached after 4 h ALA incubation. When T subpopulations of lymphocytes were labeled, T4 and T8 changes in fluorescence kinetics were similar, reaching a maximum after 5 h ALA incubation. The influence of monoclonal antibody labeling on this delayed increase for maximum fluorescence is considered. Phytohemagglutinin (PHA, incubation for 72 h) lymphocyte stimulation induced a 100% increase in PpIX fluorescence for T lymphocytes, whereas pokeweed mitogen activation produced an increase of about 50% in the B- or T-lymphocyte signal. Finally, the scanning fluorescence image clearly indicated the inhomogeneity of cytoplasmic ALA-induced PpIX fluorescence, which was probably due to the distribution of mitochondria. The influence of this heterogeneity on PpIX photosensitivity effects is discussed.

Endoscopic photodynamic therapy with haematoporphyrin derivative in gastroenterology.

Endoscopic photodynamic therapy (PDT) with haematoporphyrin derivative was used in the primary treatment of 69 patients with inoperable gastrointestinal neoplasms. Patients were divided into three groups: 31 with oesophageal squamous cell carcinoma, 17 with adenocarcinoma of the stomach or lower third of the oesophagus and 21 with rectosigmoid adenocarcinoma. After infusion of 2.5-5.0 mg haematoporphyrin derivative per kilogram of body weight, lesions were irradiated using an argon dye laser (632 nm). During a follow-up period averaging 20 months (27.9 months for 35 surviving patients), complete local tumour destruction and negative histology were observed in 32 out of 69 cases. Flow-cytometric analysis of DNA content before and after PDT suggests that a clonal selection occurs in some cases of treatment failure. The results of this open pilot study suggest the potential efficacy of PDT as a curative treatment for selected cases of inoperable gastrointestinal cancers.

Synthesis, and in vitro and in vivo evaluation of a diphenylchlorin sensitizer for photodynamic therapy.

This paper reports the synthesis of a new diphenylchlorin photosensitizer, 2,3-dihydro-5,15-di(3,5-dihydroxyphenyl)porphyrin (SIM01). The photodynamic properties, cell uptake and localization of SIM01 were compared with those of structurally related meso-tetra(hydroxyphenyl)chlorin (m-THPC). In vitro studies were conducted on rat glioma cells (C6) and human adenocarcinoma (HT-29), and in vivo studies on human colon adenocarcinoma cells (HT-29) and human prostate adenocarcinoma cells (PC3). Both dyes showed an absorption maximum at around 650 nm, with a molar extinction coefficient of 13017 M(-1) cm(-1) for SIM01 and 22718 M(-1) cm(-1) for m-THPC. Their capacity to generate singlet oxygen was identical, but differences in partition coefficients indicated that SIM01 was slightly more hydrophilic. In vitro, SIM01 was slightly more phototoxic than m-THPC for C6 cells (4.8 vs. 6.8 microg ml(-1)). However, phototoxicities were nearly identical for HT29 cells (0.45 microg ml(-1) for 5 h incubation followed by 300 mW, 20 J cm(-2)). Pharmacokinetics in vivo in mice, as determined by fibre spectrofluorimetry, showed that the SIM01 fluorescence signal in the tumor was maximal between 6 and 12 h after injection, as compared to 72 h for m-THPC. With a 2 mg kg(-1) dye dose and laser irradiation at 300 J cm(-2) (650 nm, 300 mW), the optimal PDT response occurred when the interval between injection and irradiation was 6 h for SIM01 and 24 h for m-THPC. For SIM01 with 5 mg kg(-1) injection, the optimal PDT response occurred with a 12 h delay and with the same irradiation parameters as described above, in this case the tumor response showing 40% growth. Considering the tumor volume doubling time, the value was 6.5 days in the control group and increased to 13.5 days with SIM01. Thus, SIM01 may be a powerful sensitizer characterized by strong in vitro and in vivo phototoxicity and faster tissue uptake and elimination than m-THPC.

Photosensitization of L1210 leukaemic cells by argon laser irradiation after incubation with haematoporphyrin derivative and rhodamine 123.

The selectivity and efficacy of photodynamic therapy (PDT) may be improved by the combined use of photosensitizers in a similar manner to the combined use of drugs in cancer chemotherapy. Two photosensitizers (haematoporphyrin derivative (HPD) and rhodamine 123 (Rh-123) were analysed which can be irradiated at the same wavelength (514 nm), are preferentially taken up by tumour tissue and are not specific for the same target (membrane for HPD, mitochondria for Rh-123). The analysis of the phototoxic effects in surviving fractions showed a dependence on dose for both products and a dependence on incubation time for HPD but not Rh-123. The lethal dose for 50% cell death (LD50) for HPD increased from 25 to 56 J cm-2 when the HPD dose was reduced from 2.5 to 1 micrograms ml-1 for the same incubation time. When the incubation time was increased from 15 to 45 min, the surviving fraction decreased by 37% and 17% for doses of 1 and 2.5 micrograms ml-1 respectively. For low doses (0.5 and 1 microgram ml-1), the toxicity of the two photosensitizers added simultaneously was weaker than for Rh-123 alone, whereas for high doses (2.5 micrograms ml-1) the surviving fraction was less than that obtained with Rh-123 alone. These results were compared with the light energy absorbed, the quantum yield of singlet oxygen and Rh-123 uptake as determined by flow cytometry analysis.

In vitro and in vivo spectrofluorometry of a water-soluble meta-(tetrahydroxyphenyl)chlorin (m-THPC) derivative.

The pharmacokinetics of a water-soluble derivative obtained from meta-(tetrahydroxyphenyl)chlorin (m-THPC) was evaluated in in vitro and in vivo studies. Cytoplasm fluorescence was measured in two cell models (L1210 and HT29) using a flow cytometer and a confocal microspectrofluorometer. Cells were incubated with the compound at several doses (0-150 micrograms ml-1 for flow cytometry) and for several time periods (0-6 h for microspectrofluorometry). For in vivo studies, nude mice were grafted with human adenocarcinoma 15 days before intraperitoneal injection of polyethylene glycol-m-THPC (PEG-m-THPC). Fluorescence was recorded through an optical fibre spectrofluorometer using the 660 nm peak for detection. In in vitro studies, the fluorescence was found to be proportional to the dose. Maximum fluorescence was recorded in L1210 cells earlier and more intensely than in HT29 cells (3 h at 202 +/- 14 counts s-1 and 5 h at 43 +/- 2.15 counts s-1 respectively). Concerning in vivo studies, maximum tumour fluorescence was observed 24 h after injection (3568 +/- 178 counts s-1). Selectivity was expressed by the calculated tumour-to-skin and tumour-to-muscle ratios. The time taken to observe the maximum ratios (2.95 +/- 0.16 for tumour-to-skin and 6.61 +/- 0.3 for tumour-to-muscle) was almost the same as the time taken to observe the maximum fluorescence in the tumour. Studies are in progress to correlate these results with photodynamic effects.

Modulation of colonic cancer cell adhesiveness by haematoporphyrin derivative photodynamic therapy.

Haematoporphyrin derivative photodynamic therapy (HPD-PDT) induces damage of plasma membranes and other cellular targets. This damage could modify the adhesiveness of cancer cells, which is an important parameter in cancer metastasis. We studied the effect of HPD alone and HPD incubation followed by argon laser light on the adhesiveness of progressive (PROb) or regressive (REGb) cancer cells of the same colonic origin. Adhesiveness was studied on plastic or endothelial cell monolayers (ECMs). In the absence of treatment, both PROb and REGb cells adhered better on plastic than on ECs. HPD alone and HPD-PDT induced toxicity proportional to the HPD dose. HPD-PDT increased the adhesiveness rate of both cell lines on plastic and decreased adhesiveness to ECs. HPD-PDT of ECMs increased adhesiveness but only for HPD doses giving at least 50% cell death. HPD alone and HPD-PDT of culture media led to an insignificant decrease in the cell adhesiveness to ECMs. As cells which are more metastatic are also more adherent, a decreased adhesiveness to ECMs after HPD-PDT suggests that PDT is a safe treatment considering metastasis.

Photophysical and photobiological activities of a porphyrin peptide fraction derived from haemoglobin.

In a previous study, we described the preparation of a porphyrin peptide hydrolysate from haemoglobin, its isolation and its analysis by high performance liquid chromatography (HPLC) and fast atom bombardment (FAB) mass spectrometry. The purpose of the present paper is to test the photosensitizing activity of this fraction. We determined the singlet oxygen quantum yield (phi delta) in order to quantify the efficiency of the porphyrin peptide fraction. The quantum yield is about phi(1O2)=0.06. An analysis of the phototoxic effect on tumour cells in culture was performed and compared with haematoporphyrin derivative (HpD), the only photosensitizer in clinical use at present. The phototoxicity of the porphyrin peptide fraction is weaker than that of HpD. However, for a porphyrin dose of 50 micrograms ml-1, the difference in phototoxicity is low, and in the absence of irradiation porphyrin peptides are less toxic than HpD. These results suggest that porphyrin peptides could be potent photosensitizers; moreover, they are of great interest since they allow the solubilization of hydrophobic porphyrins and could be applied in the future as insoluble photosensitizer carriers.