Novel Photosensitizers Trigger Rapid Death of Malignant Human Cells and Rodent Tumor Transplants via Lipid Photodamage and Membrane Permeabilization

BACKGROUND: Apoptotic cascades may frequently be impaired in tumor cells; therefore, the approaches to circumvent these obstacles emerge as important therapeutic modalities. METHODOLOGY/PRINCIPAL FINDINGS: Our novel derivatives of chlorin e(6), that is, its amide (compound 2) and boronated amide (compound 5) evoked no dark toxicity and demonstrated a significantly higher photosensitizing efficacy than chlorin e(6) against transplanted aggressive tumors such as B16 melanoma and M-1 sarcoma. Compound 5 showed superior therapeutic potency. Illumination with red light of mammalian tumor cells loaded with 0.1 µM of 5 caused rapid (within the initial minutes) necrosis as determined by propidium iodide staining. The laser confocal microscopy-assisted analysis of cell death revealed the following order of events: prior to illumination, 5 accumulated in Golgi cysternae, endoplasmic reticulum and in some (but not all) lysosomes. In response to light, the reactive oxygen species burst was concomitant with the drop of mitochondrial transmembrane electric potential, the dramatic changes of mitochondrial shape and the loss of integrity of mitochondria and lysosomes. Within 3-4 min post illumination, the plasma membrane became permeable for propidium iodide. Compounds 2 and 5 were one order of magnitude more potent than chlorin e(6) in photodamage of artificial liposomes monitored in a dye release assay. The latter effect depended on the content of non-saturated lipids; in liposomes consisting of saturated lipids no photodamage was detectable. The increased therapeutic efficacy of 5 compared with 2 was attributed to a striking difference in the ability of these photosensitizers to permeate through hydrophobic membrane interior as evidenced by measurements of voltage jump-induced relaxation of transmembrane current on planar lipid bilayers. CONCLUSIONS/SIGNIFICANCE: The multimembrane photodestruction and cell necrosis induced by photoactivation of 2 and 5 are directly associated with membrane permeabilization caused by lipid photodamage

Antibodies Contributing to Focal Epilepsy Signs and Symptoms Score

Objective: Diagnosing autoimmune encephalitis (AIE) is difficult in patients with less fulminant diseases such as epilepsy. However, recognition is important, as patients require immunotherapy. This study aims to identify antibodies in patients with focal epilepsy of unknown etiology, and to create a score to preselect patients requiring testing. Methods: In this prospective, multicenter cohort study, adults with focal epilepsy of unknown etiology, without recognized AIE, were included, between December 2014 and December 2017, and followed for 1 year. Serum, and if available cerebrospinal fluid, were analyzed using different laboratory techniques. The ACES score was created using factors favoring an autoimmune etiology of seizures (AES), as determined by multivariate logistic regression. The model was externally validated and evaluated using the Concordance (C) statistic. Results: We included 582 patients, with median epilepsy duration of 8 years (interquartile range = 2–18)

Curr Opin Genet Dev

The need for quantification and real time visualization of developmental processes has called for increasingly sophisticated imaging techniques. Among them, multiphoton microscopy reveals itself to be an extremely versatile tool owing to its unique ability to combine fluorescent imaging, laser ablation, and higher harmonic generation. Furthermore, recent advances in femtosecond lasers and optical parametric oscillators (OPO) are now opening doors for imaging at unprecedented wavelengths centered in the tissue transparency window. This Review describes promising multiphoton approaches using OPO and the growing number of useful applications of non-linear microscopy in the field of developmental biology. Basic characteristics associated with these techniques are described along with the main experimental challenges when applied to embryo imaging

Photosensitizing properties of chlorins in solution and in membrane-mimicking systems.

International audienc

Advances in polarization sensitive multiphoton nano-bio-imaging

In this talk, we shall shortly review four main directions of ongoing research in our laboratories, directed at the conception and demonstration of a variety of innovative configurations in nanoscale multiphoton imaging. A common feature to all of these directions appears to be the central role played by the involvement of polarization features, both in- and outgoing, moreover so in view of the tensorial aspects inherent to nonlinear schemes such second-harmonic generation, electro-optic modulation or two-photon fluorescence which will ne emphasized. These advances relate to the new domain of nonlinear ellipsometry in multiphoton imaging [1], of high relevance to fundamental aspects of nanophotonics and nanomaterial engineering as well as towards basic life science issues. The four domains to be shortly reported are: a) polarization resolved second-harmonic generation in semiconductor QD’s with record small sizes in the 10-12 nm range [2] b) original use of two-photon confocal polarization resolved microscopy in DNA stained by two photon fluorescent dyes in different LC phases arrangements so as to characterize these as well as ascertain the respective DNA-dye orientation (intercalant or groves) [3] c) elaboration and demonstration of an electrooptic confocal microscope in a highly sensitive interferometric and homodyne detection configuration allowing to map weak electric potentials such as in artificial functionalized membranes, the dynamical investigation of firing and propagation aspects of action potentials in neurones being currently the next step [4] d) original plasmon based enhanced nanoscale confocal imaging involving a dual detection scheme (fluorescence imaging and ATR plasmon coupling in reflection) whereby adequate preparation and switching of the incoming polarization state between radial, linear and azimuthal configurations, entail different images and plasmon enhancement levels [5]

Advances in the scintillation performance of LuYAP:Ce single crystals

In the last years, there has been an effort to study and improve the performance of cerium doped Lu0.7Y0.3AlO3 crystals. Since the first grown boules produced with the Czochralski technique, significant progress has been made in the crystal growth process that has resulted in larger crystal ingots and in important improvements of the scintillation properties. In this study, the results in light yield, energy resolution and decay time will be presented from the first studied batches, grown in the pre-production phase, as well as from crystals of the mass production. The optical characteristics such as transmission and absorption spectra were investigated and important correlations with the scintillation properties will be pointed out. The pixels produced in large quantities are going to be implemented in several small animal PET scanners and therefore the observed consistency of the scintillation properties is of great importance for the performance of these devices