Assessment of the Grisotti oncoplastic procedure for the management of central breast tumors.

INTRODUCTION: The Grisotti technique consists to excise central breast tumor with nipple areolar and mobilize a dermo-glandular flap which is de-epithelized in order to reshape the breast and recreate an areola. The objective was to assess oncological results, postoperative side-effects, and patient and surgeon satisfaction rates resulting from this technique. MATERIALS AND METHODS: From September 2016 to December 2019, 38 patients have been treated with a central breast tumor using the Grisotti technique. RESULTS: The mean age was 61.6 ± 11. The median body mass index was 27 kg/m² [20-42]. Thirty one patients benefited from a sentinel lymph node dissection. Preoperative histology found a majority of invasive ductal carcinomas (IDC) (71%). There were no intraoperative complications, and the average operating time was 90 min [60-200]. Postoperative histology found IDC associated with ductal carcinoma in situ in 28 patients. The surgical margins were invaded in two patients (reoperated by mastectomy after adjuvant treatment) and invasion of a margin of less than 1 mm in another six patients (supplemented by re-excision). The main postoperative complications were an abscess of the operating site and a partial necrosis of the neo-areola. The appearance of the breasts after radiotherapy gives a high satisfaction rate, both for patients and for surgeons. CONCLUSION: The Grisotti technique is an easily reproducible procedure without major complications. It makes it possible to perform a carcinological satisfactory central lumpectomy, correction of the central glandular defect, and reconstruction of a new areola.

Clinical evaluation of a device providing simultaneous white-light and fluorescence video streams as well as panoramic imaging during fluorescence assisted-transurethral resection of bladder cancer.

The current clinical study is aimed at evaluating the clinical relevance of an innovative device (called CyPaM2 device) that for the first time provides urologists with (i) a panoramic image of the bladder inner wall within the surgery time, and with (ii) a simultaneous (bimodal) display of fluorescence and white-light video streams during the fluorescence assisted-transurethral resection of bladder cancers procedure. The clinical relevance of this CyPaM2 device was evaluated on 10 patients according to three criteria (image quality, fluorescent lesions detection relevance, and ergonomics) compared with a reference medical device. Innovative features displayed by the CyPaM2 device were evaluated without any possible comparison: (i) simultaneous bimodal display of white-light and fluorescence video streams, (ii) remote light control, and (iii) time delay for the panoramic image building. The results highlight the progress to achieve in order to obtain a fully mature device ready for commercialization and the relevance of the innovative features proposed by the CyPaM2 device confirming their interest.

Sentinel lymph node identification using superparamagnetic iron oxide particles versus radioisotope: The French Sentimag feasibility trial.

BACKGROUND AND OBJECTIVES: The French Sentimag feasibility trial evaluated a new method for the localization of breast cancer sentinel lymph node (SLN) using Sienna+®, superparamagnetic iron oxide particles, and Sentimag® detection in comparison to the standard technique (isotopes ± blue dye). METHODS: We conducted a prospective multicentric paired comparison trial on 115 patients. SLN localization was performed using both the magnetic technique and the standard method. Detection rate and concordance between magnetic and standard tracers were calculated. Post-operative complications were assessed after 30 days. RESULTS: Results are based on 108 patients. SLN identification rate was 98.1% [93.5-99.8] for both methods, 97.2% [92.1-99.4] for Sienna+® and 95.4% [89.5-98.5] for standard technique. A mean of 2.1 SLNs per patient was removed. The concordance rate was 99.0% [94.7-100.0%] per patient and 97.4% [94.1-99.2] per node. Forty-six patients (43.4%) had nodal involvement. Among involved SLNs, concordance rate was 97.7% [88.0-99.9] per patient and 98.1% [90.1-100.0] per node. CONCLUSIONS: This new magnetic tracer is a feasible method and a promising alternative to the isotope. It could offer benefits for ambulatory surgery or sites without nuclear medicine departments. J. Surg. Oncol. 2016;113:501-507. © 2016 Wiley Periodicals, Inc.

Multifunctional ultrasmall nanoplatforms for vascular-targeted interstitial photodynamic therapy of brain tumors guided by real-time MRI.

Photodynamic therapy (PDT) for brain tumors appears to be complementary to conventional treatments. A number of studies show the major role of the vascular effect in the tumor eradication by PDT. For interstitial PDT (iPDT) of brain tumors guided by real-time imaging, multifunctional nanoparticles consisting of a surface-localized tumor vasculature targeting neuropilin-1 (NRP-1) peptide and encapsulated photosensitizer and magnetic resonance imaging (MRI) contrast agents, have been designed. Nanoplatforms confer photosensitivity to cells and demonstrate a molecular affinity to NRP-1. Intravenous injection into rats bearing intracranial glioma exhibited a dynamic contrast-enhanced MRI for angiogenic endothelial cells lining the neovessels mainly located in the peripheral tumor. By using MRI completed by NRP-1 protein expression of the tumor and brain adjacent to tumor tissues, we checked the selectivity of the nanoparticles. This study represents the first in vivo proof of concept of closed-head iPDT guided by real-time MRI using targeted ultrasmall nanoplatforms. From the clinical editor: The authors constructed tumor vascular peptide targeting multifunctional silica-based nanoparticles, with encapsulated gadolinium oxide as MRI contrast agent and chlorin as a photosensitizer, as a proof of concept novel treatment for glioblastoma in an animal model.

Targeted photodynamic therapy in head and neck squamous cell carcinoma: heading into the future.

The aim of this article is to give an insight into the future of photodynamic therapy (PDT) in head and neck squamous cell carcinoma (HNSCC). Through the combination of a photosensitizing agent with light and oxygen, PDT produces highly cytotoxic reactive oxygen species leading to selective tumor eradication. PDT is an attractive treatment for focal therapy of localized tumors, especially in the case of unresectable tumors. In HNSCC, over 1500 patients have been treated by PDT, and the majority of them responded quite favorably to this treatment. However, the non-negligible photosensitization of healthy tissue is a major limitation for the clinical application of PDT. Improvement in tumor selectivity is the main challenge that can be taken up by the use of a new generation of photosensitizing nanoparticles. Passive targeting, by using functionalised nanocarriers to target to overexpressed transmembrane receptors afford attractive solutions. To this day, epidermal growth factor receptor (EGFR) remains the only validated molecular target for HNSCC, and photosensitizer immunoconjugates to EGFR have been developed for the intracellular delivery of photosensitizing agents. Depending on coordinated research between biomarkers, specific ligands, and photosensitizers, similar approaches could be rapidly developed. In addition, some photosensitizers hold high fluorescence yield and therefore could emerge as theranostic agents.

How to avoid local side effects of bladder photodynamic therapy: impact of the fluence rate.

PURPOSE: We studied how to avoid irritative bladder symptoms after bladder photodynamic therapy, such as urgency, frequency and pain, which are associated with the inflammation and destruction of normal urothelium. MATERIALS AND METHODS: Rats bearing orthotopic bladder tumors were instilled with hexyl-aminolevulinate and illuminated with red light at a high vs low (100 vs 15 mW/cm(2)) fluence rate. Cystectomy specimens 48 hours after treatment were subjected to anatomopathological examination. Inflammatory reaction and apoptosis were evaluated. In vivo photobleaching was assessed during illumination at each fluence rate. RESULTS: All superficial tumors were eradicated irrespective of light dose and fluence rate. High fluence rates induced necrosis with inflammatory reaction and absent normal urothelium. Low fluence rates did not provoke inflammation and resulted in apoptotic cell death with preserved urothelial integrity. This could be attributable to faster photobleaching of the photosensitizer in normal urothelium at low fluence rates. CONCLUSIONS: Bladder photodynamic therapy at a low fluence rate minimizes side effects without hampering therapeutic efficacy.

Treatment of vulvar intraepithelial neoplasia with CO(2) laser vaporization and excision surgery.

OBJECTIVE: To evaluate the recurrence rate after a single treatment of vulvar intraepithelial neoplasia (VIN) with CO(2) laser vaporization. MATERIALS AND METHODS: Fifty women with usual-type or differentiated VIN (grades 2 and 3) treated with CO(2) laser vaporization or surgery excision (cold knife or CO(2) laser) were retrospectively evaluated. RESULTS: Of the 50 patients, 41 (82.0%) had usual-type VIN and 9 (18.0%) had differentiated VIN. Moreover, 24 (48.0%) were treated with surgery excision and 26 (52.0%) underwent CO(2) laser vaporization. Laser-treated patients were significantly younger (p < .01) with more multifocal (p < .05) and multicentric lesions (p < .01) than in the surgery group. Recurrence-free survival (RFS) rates at 1 year were 91.0% for the surgery and 65.2% for the laser vaporization groups (p < .01). At 5 years, RFS rates were unchanged for the surgery group and dropped to 51.3% (p < .01) for the laser group. On the univariate analysis, current smoker (p = .03), multicentric VIN (p = .02), and laser vaporization treatment (p < .01) had a statistically significant impact on RFS. One patient progressed to invasive cancer (2%). CONCLUSIONS: The recurrence rate after CO(2) laser vaporization requires regular, close, and extended monitoring.

Diagnostic performance of one-step nucleic acid amplification for intraoperative sentinel node metastasis detection in breast cancer patients.

The purpose of this prospective multicenter study was to assess one-step nucleic acid amplification (OSNA) for intraoperative sentinel lymph node (SLN) metastasis detection in breast cancer patients, using final histology as the reference standard. OSNA results were also compared to intraoperative histology SLN evaluation and to standard clinicopathological risk markers. For this study, fresh SLNs were cut in four blocks, and alternate blocks were used for OSNA and histology. CK19 mRNA copy number was categorized as strongly positive, positive or negative. Positive histology was defined as presence of macrometastasis or micrometastasis. When discrepancies occurred, the entire SLNs were subjected to histological studies and the node lysates to additional molecular studies. Five hundred three SLN samples from 233 patients were studied. Mean time to evaluate two SLNs was 40 min. Sensitivity per patient was 91.4% (95% CI, 76.9-98.2%), specificity 93.3% (95% CI, 88.6-96.6%), positive likelihood ratio 13.7 and negative likelihood ratio 0.1. Sensitivity was 63.6% for frozen sections and 47.1% for touch imprint cytology. Both methods were 100% specific. Positive histology and positive OSNA were significantly associated with highest clinical stage, N1 status and vascular invasion; and OSNA results correlated with HER2/neu status and benefited patients with negative histology. These findings show that OSNA assay can allow detection of SLN metastasis in breast cancer patients intraoperatively with a good sensitivity, thus minimizing the need for second surgeries for axillary lymph node detection.

Fluorescence diagnosis of bladder cancer: a novel in vivo approach using 5-aminolevulinic acid (ALA) dendrimers.

UNLABELLED: What's known on the subject? and What does the study add? Fluorescence cystoscopy with hexylaminolevulinate (h-ALA, Hexvix®) is known to improve tumour detection in non-muscle-invasive bladder cancer. However, specificity is relatively low and the intensity of the observed fluorescence signal decreases over time due to protoporphyrin IX (PpIX) efflux. This study evaluates in an in vivo model the use of a dendritic 5-aminolevulinic acid compound for fluorescence diagnosis. Fluorescence ratios between tumour and urothelium as well as muscle were significantly better as compared with h-ALA. Sustained synthesis of PpIX accounts for preservation of fluorescence for >24 h. OBJECTIVE: • To overcome the relative lack of tumour selectivity of fluorescence-guided cystoscopy using 5-aminolevulinic acid (ALA) or its ester derivative (e.g. hexylaminolevulinate, h-ALA; Hexvix®), we evaluated the use of dendrimers bearing different ALA loads in rats bearing orthotopic bladder tumours. MATERIALS AND METHODS: • Rat bladders were instilled with h-ALA or ALA dendrimers and fluorescence ratio between tumour and normal urothelium, as well as tumour and muscle and depth of fluorescence were determined with Image J software. • Quantification of ALA and/or esters systemic reabsorption was evaluated by high-performance liquid chromatography. RESULTS: • Slow hydrolysis of ALA from dendrimers as observed in vitro implies a higher initial ALA load and longer resting times in vivo. Sustained synthesis of protoporphyrin IX (PpIX) explains persistence of fluorescence for >24 h. • There were significantly better fluorescence ratios with dendrimers, as well as higher penetration depths and absence of systemic reabsorption. CONCLUSION: • The prolonged and sustained PpIX synthesis, the improved tumour selectivity with a deeper penetration and the absence of systemic reabsorption are primary indicators that ALA dendrimers could be an alternative to h-ALA in fluorescence-guided cystoscopy.

Quantum dot-folic acid conjugates as potential photosensitizers in photodynamic therapy of cancer.

This study examined the in vitro potential of bioconjugated quantum dots (QDs) as photosensitizers for photodynamic therapy (PDT). According to our previous approaches using photosensitizers, folic acid appears to be an optimal targeting ligand for selective delivery of attached therapeutic agents to cancer tissues. We synthesized hydrophilic near infrared emitting CdTe(S)-type QDs conjugated with folic acid using different spacers. Photodynamic efficiency of QDs conjugated or not with folic acid was evaluated on KB cells, acting as a positive control due to their overexpression of FR-α, and HT-29 cells lacking FR-α, as negative control. A design of experiments was suggested as a rational solution to evaluate the impacts of each experimental factor (QD type and concentration, light fluence and excitation wavelength, time of contact before irradiation and cell phenotype). We demonstrated that, for concentrations lower than 10 nM, QDs displayed practically no cytotoxic effect without light exposure for both cell lines. Whereas QDs at 2.1 nM displayed a weak photodynamic activity, a concentration of 8 nM significantly enhanced the photodynamic efficiency characterized by a light dose-dependent response. A statistically significant difference in photodynamic efficiency between KB and HT-29 cells was evidenced in the case of folic acid-conjugated QDs. Optimal conditions led to an enhanced photocytotoxicity response, allowing us to validate the ability of QDs to generate a photodynamic effect and of folic acid-conjugated QDs for targeted PDT.

Redistribution of meta-tetra(hydroxyphenyl)chlorin (m-THPC) from conventional and PEGylated liposomes to biological substrates.

We used the phenomenon of previously described photoinduced fluorescence quenching and fluorescence polarization to evaluate the transfer of meta-tetra(hydroxyphenyl)chlorin (m-THPC) from commercial high-drug load liposomes to plasma proteins and model membranes. Fluorescence quenching of m-THPC in liposomes by iodide indicates that part of m-THPC in PEGylated liposomes is localized in the PEG shell, while the rest is bound to the lipid bilayer. It was shown that the two molecule pools in the commercial PEGylated liposomal formulation Fospeg® condition the characteristics of the m-THPC release kinetics. A substantial percentage of m-THPC from Fospeg® is released much faster than from the conventional liposomal formulation Foslip®. Using the technique of resonance light scattering, it was shown that partial m-THPC aggregation is present in liposomes with very high drug loads, higher in PEGylated liposomes compared to conventional ones.

Intradermal tacrolimus prevent scar hypertrophy in a rabbit ear model: a clinical, histological and spectroscopical analysis.

BACKGROUND: Keloids and hypertrophic scars (HSc) affect 4.5-16% of the population. Thus far, the different approaches of keloid treatment are not very efficient, with a 50% relapse rate and many ongoing researches are looking for simple, safe and more efficient therapeutic methods. Tacrolimus is an immunomodulator that could be useful in treating keloid. OBJECTIVES: The objective of this study is to evaluate the effectiveness of Tacrolimus in inhibiting HSc formation on rabbits' ears model and to check optical skin spectroscopy in tissue characterization. METHODS: Our study was carried out on 20 New-Zealand female white rabbits. HSc were obtained by wounding rabbits' ear. These wounds were treated with intradermal injections of tacrolimus (0.2-0.5 mg/cm(2)) or a vehicule. The assessment of treatment efficacy was performed by clinical examinations, histological assay and skin spectrometry. RESULTS: Tacrolimus did not induce general or local side-effects. The scar elevation index in treated subjects was half less than that of the untreated ones. Furthermore, dermal thickness and inflammatory cellular density were both significantly smaller for treated scars than for the control ones. In vivo optical skin spectroscopy can characterize hypertrophic and normal skin with high sensibility and specificity. CONCLUSION: Intradermal injection of tacrolimus at 0.5 mg/cm(2) is an efficient way to prevent HSc in our experiment model and its tolerance is correct. Optical spectroscopy could be a good non-invasive tool to evaluate HSc treatment. These promising results might be proposed for patients suffering from keloid.

[Metaplastic carcinomas of the breast: a morphological and immunohistochemical study]. / Les carcinomes métaplasiques du sein : une étude morphologique et immunohistochimique.

INTRODUCTION: Metaplastic carcinomas of the breast are rare and form a heterogenic group of tumors, characterized by the presence of squamous or sarcomatoid differentiation. PATIENT AND METHODS: In 23 cases, we study the main histoprognostic features, hormonal status, and the expression of HER2, CK5/6, CK14, p63, EGFR, beta-catenin, MUC1 and E-cadherin, the expression of this seven last antigens being also studied in nodal metastases. RESULTS: The different metaplastic types are spindle cell carcinoma (35%), squamous cell carcinoma (26%), osteo- or chondrosarcomatoid (11%) or mixed type (26%). Vascular emboli are seen in 30% of the tumors and perinervous infiltration in 4%. 33% of the patients have nodal metastases. The immunohistochemical features are: RO+: 4%; RP+: 8%; HER2+: 0%; p63+: 74%; CK14+: 83%; CK5/6+: 74%; EGFR+: 100%; E-cadherin+: 70%; beta-catenin: aberrant staining (cytoplasm or weak membrane staining greater than 5%): 74%, negative: 13%; MUC1: aberrant staining (cytoplasm or complete membrane staining greater than 5%): 35%, pure partial membrane staining: 22%, negative: 43%. In 43% of tumors, more aberrant staining for MUCI is present in nodal metastases compared with primitive tumor. CONCLUSION: Metaplastic carcinomas are aggressive tumors, generally with a "triple-negative" and basal phenotype. The expressions of MUC1 and beta-catenin are often absent or aberrant, which could favor metastatic dissemination.

Neuropilin-1 targeting photosensitization-induced early stages of thrombosis via tissue factor release.

PURPOSE: This article characterizes the vascular effects following vascular-targeted photodynamic therapy with a photosensitizer which actively targets endothelial cells. METHODS: This strategy was considered by coupling a chlorin to a heptapeptide targeting neuropilin-1 in human malignant glioma-bearing nude mice. A laser Doppler microvascular perfusion monitor was used to monitor microvascular blood perfusion in tumor tissue. Endothelial cells' ultra structural integrity was observed by transmission electron microscopy. The consequences of photosensitization on tumor vessels, tissue factor expression, fibrinogen consumption, and thrombogenic effects were studied by immunohistochemical staining. RESULTS: Treatment of glioma-bearing mice with the conjugate showed a statistically significant tumor growth delay. Vascular effect was characterized by a decrease in tumor tissue blood flow at about 50% baseline during treatment not related to variations in temperature. This vascular shutdown was mediated by tumor blood vessels' congestion. A pro-thrombotic behavior of targeted endothelial cells in the absence of ultra structural changes led to the induction of tissue factor expression from the earliest times post-treatment. Expression of tissue factor-initiated thrombi formation was also related to an increase in fibrinogen consumption. CONCLUSION: Using a peptide-conjugated photosensitizer targeting neuropilin-1, induction of tissue factor expression immediately post-treatment, led to the establishment of thrombogenic effects within the vessel lumen.

Validation of the Tenon breast cancer score for predicting non-sentinel lymph node status in breast cancer patients with sentinel lymph node metastasis: a prospective multicenter study.

BACKGROUND: Axillary lymph node dissection (ALND) is the standard treatment for patients with sentinel node (SN) metastasis, but most of these patients have negative non-sentinel nodes (non-SN). We have developed a scoring system (the Tenon score) to help identify a subgroup of patients who have a low risk of having non-SN metastases and who may thus forgo ALND. Here we validated the Tenon score in an independent cohort of SN-positive patients. PATIENTS AND METHODS: We tested the accuracy of the Tenon score for predicting non-SN status in a prospective multicenter study of 226 SN-positive breast cancer patients. We calculated the false-negative rate, sensitivity, specificity, and positive (PPV) and negative predictive values (NPV). Receiver operating characteristics (ROC) curves were constructed and the areas under the curve (AUC) were calculated as a measure of discriminatory capacity. RESULTS: At least one non-SN was positive in 63 patients (27.9%). One hundred and twenty (53.1%) of the 226 patients had a Tenon score of 3.5 or less. Among these 120 patients, five had at least one positive non-SN. With a score cut-off of 3.5, the negative predictive value was 95.8% and the false-negative rate was 4.2%. Overall, the Tenon score accurately predicted non-SN status, with an AUC of 0.82 (95% confidence interval, 0.77-0.88). CONCLUSION: In this multicenter study of an independent patient population, the Tenon score was accurate and reproducible for predicting non-SN status in breast cancer patients. The simplicity and reliability of the variables on which the Tenon score is based may be an advantage over other scoring systems.

Assessment of apoptosis by immunohistochemistry to active caspase-3, active caspase-7, or cleaved PARP in monolayer cells and spheroid and subcutaneous xenografts of human carcinoma.

Immunohistochemistry to active caspase-3, recently recommended for apoptosis detection, is inappropriate to detect apoptosis involving caspase-7. Cleavage of poly-ADP-ribose polymerase 1 (PARP-1), a major substrate of both caspases, is a valuable marker of apoptosis. Apoptosis evaluation induced in vitro either by paclitaxel or by photodynamic treatment (PDT) with Foscan in HT29 or KB monolayer cells and HT29 spheroids yielded a close percentage of labeled cells whatever the antibody used, whereas in control specimens, cleaved PARP (c-PARP) immunostaining failed to detect apoptosis as efficiently as active caspase-3 or -7 immunostaining. Studies in MDA-MB231 monolayer cells and HT29 xenografts either subjected or not subjected to Foscan-PDT resulted in a significant higher number of active caspase-3-labeled cells, although immunofluorescence analysis showed c-PARP and active caspase-3 perfectly colocalized in tumors. A restricted expression of c-PARP was obvious in the greater part of caspase-3 expressing cells from control tumor, whereas photosensitized tumors showed a higher number of cells expressing large fluorescent spots from both active caspase-3 and c-PARP. These results support the assumption that c-PARP expression was dependent on treatment-induced apoptosis. The absence of caspase-7 activation in some caspase-3-expressing cells undergoing Foscan-PDT shows the relevance of using antibodies that can discriminate caspase-dependent apoptotic pathways.

Preventing bladder tumor implantation with photodynamic therapy in a rat model mimicking post-fluorescence guided transurethral resection.

PURPOSE: Fluorescence guided transurethral resection has gained acknowledgment from the urological community and it is progressively becoming more applied. It has been shown to decrease the recurrence rate of nonmuscle invasive bladder cancer due to incomplete resection due to lack of visualization. The implantation of viable tumor cells seeded during transurethral resection is another reason for recurrence. We investigated whether applying photodynamic therapy on sensitized tumor cells would decrease the amount of viable intraluminal cells and tumor cell implantation. MATERIAL AND METHODS: Two models were designed to mimic the situation after fluorescence guided transurethral resection, including partly or fully de-epithelialized bladders and circulating tumor cells loaded with protoporphyrin IX. Photodynamic therapy was performed. Controls consisted of no drug with no light, light only and drug only. Immediately after photodynamic therapy the intravesical contents were retrieved and clonogenic assays were performed on cells. Bladders were harvested 10 days after cell administration and subjected to pathological analysis. RESULTS: In the photodynamic therapy and control groups tumor volume was proportional to the instilled cell load. Clonogenic assays showed that viable cells were decreased a tenth of the initial administered amount. Tumor implantation decreased to less than a fifth of control values. CONCLUSIONS: Photodynamic therapy can effectively decrease the amount of viable tumor cells in the bladder lumen. This results in a significant decrease in tumor implantation. This technique could possibly be used to further decrease the recurrence rate of nonmuscle invasive bladder cancer.

Monte Carlo modeling of multilayer phantoms with multiple fluorophores: simulation algorithm and experimental validation.

This work is first a description of a statistical simulation algorithm developed for simulating the spectral absorption and emission of several fluorophores in an absorbing and diffusing multilayer model. Second, a detailed experimental validation of the simulation program is conducted on two sets of liquid and solid multilayer phantoms, containing one, two, or three fluorophores, within absorbing and scattering media. Experimental spatially resolved reflectance spectra are acquired in the wavelength band 400 to 800 nm and compared to corresponding simulated spectra. The degree of similarity between experimentation and simulation data is quantified. The results obtained underline good correlations with mean errors varying from 2 to 10%, depending on the number of layers and on the complexity of the phantom's composition.

Classification of ultraviolet irradiated mouse skin histological stages by bimodal spectroscopy: multiple excitation autofluorescence and diffuse reflectance.

Histopathological analysis and in vivo optical spectroscopy were used to discriminate several histological stages of UV-irradiated mouse skin. At different times throughout the 30-week irradiation, autofluorescence (AF) and diffuse reflectance (DR) spectra were acquired in a bimodal approach. Then skin was sampled and processed to be classified, according to morphological criteria, into four histological categories: normal, and three types of hyperplasia (compensatory, atypical, and dysplastic). After extracting spectral characteristics, principal component analysis (data reduction) and the k-nearest neighbor classifying method were applied to compare diagnostic performances of monoexcitation AF (based on each of the seven excitation wavelengths: 360, 368, 390, 400, 410, 420, and 430 nm), multiexcitation AF (combining the seven excitation wavelengths), DR, and bimodal spectroscopies. Visible wavelengths are the most sensitive ones to discriminate compensatory from precancerous (atypical and dysplastic) states. Multiexcitation AF provides an average 6-percentage-point increased sensitivity compared to the best scores obtained with monoexcitation AF for all pairs of tissue categories. Bimodality results in a 4-percentage-point increase of specificity when discriminating the three types of hyperplasia. Thus, bimodal spectroscopy appears to be a promising tool to discriminate benign from precancerous stages; clinical investigations should be carried out to confirm these results.

Unusual photoinduced response of mTHPC liposomal formulation (Foslip).

Liposomal formulations of meso-tetra(hydroxyphenyl)chlorin (mTHPC) have already been proposed with the aim to optimize photodynamic therapy. Spectral modifications of these compounds upon irradiation have not yet been investigated. The objective of this study was to evaluate photobleaching properties of mTHPC encapsulated into dipalmitoylphosphatidylcholine (DPPC) liposomes, Foslip. Fluorescence measurements in DPPC liposomes with different DPPC:mTHPC ratios demonstrated a dramatic decrease in fluorescence anisotropy with increasing local mTHPC concentration, thus suggesting strong interactions between mTHPC molecules in lipid bulk medium. Exposure of Foslip suspensions to small light doses (<50 mJ/cm(2)) resulted in a substantial drop in fluorescence, which, however, was restored after addition to the sample of a non-ionic surfactant Triton X-100. We attributed this behavior to photoinduced fluorescence quenching. This effect depended strongly on the molar DPPC:mTHPC ratio and was revealed only for high local mTHPC concentrations. The results were interpreted supposing energy migration between closely located mTHPC molecules with its subsequent dissipation by the molecules of photoproduct acting as excitation energy traps. We further assessed the effect of photoinduced quenching in plasma protein solution. Relatively slow kinetics of photoinduced Foslip response during incubation in the presence of proteins was attributed to mTHPC redistribution from liposomal formulations to proteins. Therefore, changes in mTHPC distribution pattern in biological systems would be consistent with changes in photoinduced quenching and would provide valuable information on mTHPC interactions with a biological environment.