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Biomedical subjects

D Lignon

Publications and source records attributed to D Lignon.

5 recordsLinked to original sources
PubMed1996

[In vitro comparison of the photodynamic activity of meso-tetra (m-hydroxyphenyl) chlorin and hematoporphyrin derivative].

Meso-tetra (hydroxyphenyl) chlorin (mTHPC) was evaluated in vitro in HT29 human colon adenocarcinoma cell line and compared with hematoporphyrin derivative (HpD). The incorporation kinetics, evaluated by flow cytometry showed that mTHPC and HpD cellular uptake was related to the incubation time until 12 hours, then a plateau appeared. Cytotoxicity assays were performed using MTT test after photoirradiation at 650 nm for mTHPC and 630 nm for HpD. The photodynamic activity of both photosensitizers was influenced by serum protein of the culture medium and time interval between irradiation and photocytotoxicity test with a maximal activity 24 and 48 hrs after the photoirradiation. In optimized experimental conditions i.e. 2% serum protein- containing culture medium, 24 hr-incubation period, cytotoxicity measured 48 hrs after exposure, 10 J/cm2 light fluence, mTHPC appeared approximately 20-fold more active than HpD with IC50 values of 0.2 micrograms/mL and 4.2 micrograms/mL, respectively.

Adenocarcinoma↗
PubMed1992

MTT assays allow quick and reliable measurement of the response of human tumour cells to photodynamic therapy.

MCF-7 and HT-29 cell lines were selected as a reliable model to examine the possible parameters affecting the sensitivity of tumour cells to photodynamic therapy (PDT) using a dye-laser at 630 nm. The chemical composition of haematoporphyrin derivative (HPD) was determined by high-performance liquid chromatography (HPLC) analysis and was in agreement with reported values. MTT assays were performed to assess the time-dependency of PDT and the influence of the output power and light fluence. The results showed a maximal cytotoxicity 48 h after photoirradiation. The output power (1 or 2 W) did not significantly affect the cytotoxicity when the fluence was constant (20 J/cm2). However, an increase in fluence (10-40 J/cm2) led to a significant enhancement of cytotoxicity until maximal values were reached (30-40 J/cm2). A further increase in fluence (50 J/cm2) proved to induce a fall-off in cytotoxicity related to the intense photobleaching of HPD.

Adenocarcinoma↗
PubMed1992

[Photodynamic therapy of bronchogenic cancer].

Photodynamic therapy (PDT) means the activation by light of an exogenous photosensitizer previously retained by tumors. This therapeutic method is under current investigation for lung cancer. A review of the literature presents the preliminary results bearing upon more than 200 epidermoid bronchus carcinomas. A complete response rate of 75% can be anticipated for early tumors. Several survivals beyond five years, due to PDT alone, have already been reported. Two phase III trials are opened, comparing PDT vs YAG laser for obstructing tumors and PDT+Radiotherapy vs Radiotherapy alone for non-operable small tumors. PDT should be developed in selected indications of lung cancer, because it is an original and interesting therapeutic solution.

Bronchoscopy↗