Photodynamic therapy (PDT) is a clinically approved, minimally invasive therapeutic procedure that can exert a selective cytotoxic activity toward malignant cells. The procedure involves administration of a photosensitizing agent followed by irradiation at a wavelength corresponding to an absorbance band of the sensitizer. In the presence of oxygen, a series of events lead to direct tumor cell death, damage to the microvasculature, and induction of a local inflammatory reaction. Clinical studies revealed that PDT can be curative, particularly in early stage tumors. It can prolong survival in patients with inoperable cancers and significantly improve quality of life. Minimal normal tissue toxicity, negligible systemic effects, greatly reduced long-term morbidity, lack of intrinsic or acquired resistance mechanisms, and excellent cosmetic as well as organ function-sparing effects of this treatment make it a valuable therapeutic option for combination treatments. With a number of recent technological improvements, PDT has the potential to become integrated into the mainstream of cancer treatment. CA Cancer J Clin 2011;61:250-281. V C

/pdf/photodynamic-therapy-of-cancer-an-update-4fcrlehb17.pdf

Photodynamic therapy of cancer: An update†‡

With digital equipment becoming increasingly networked, either on wired or wireless networks, for personal and professional use alike, distributed software systems have become a crucial element in information and communications technologies. The study of these systems forms the core of the ARLES' work, which is specifically concerned with defining new system software architectures, based on the use of emerging networking technologies. In this context, we concentrate on the study of distributed systems which bring to life the vision of ubiquitous computing systems, also known as ambient intelligence.

반도체 공정 overview

Reactive oxygen species (ROS) play an essential role in regulating various physiological functions of living organisms. The intrinsic biochemical properties of ROS, which underlie the mechanisms ne...

Reactive Oxygen Species (ROS)-Based Nanomedicine.

Photodynamic therapy - mechanisms, photosensitizers and combinations.

This review describes the diffusion model for light transport in tissues and the medical applications of diffuse light. Diffuse optics is particularly useful for measurement of tissue hemodynamics, wherein quantitative assessment of oxy- and deoxy-hemoglobin concentrations and blood flow are desired. The theoretical basis for near-infrared or diffuse optical spectroscopy is developed, and the basic elements of diffuse optical tomography are outlined. We also discuss diffuse correlation spectroscopy, a technique whereby temporal correlation functions of diffusing light are transported through tissue and are used to measure blood flow. Essential instrumentation is described, and representative brain and breast functional imaging and monitoring results illustrate the workings of these new tissue diagnostics.

/pdf/diffuse-optics-for-tissue-monitoring-and-tomography-curjv2s4p6.pdf

Diffuse optics for tissue monitoring and tomography

Antibacterial activity of photoactivated zinc oxide nanoparticles (ZnO NPs) against human pathogens Escherichia coli O157:H7, Listeria monocytogenes ATCL3C 7644 and plant pathogen Botrytis cinerea was investigated. Data indicate that photoactivated (λ = 400 nm) ZnO NPs at concentration 1 × 10(-3)M and incubation time 60 min reduced population of both bacteria by 7 log (CFU/ml). Clear dependence of antimicrobial properties of ZnO NPs on used concentration and incubation time was found. Scanning electron microscopy (SEM) images of treated bacteria indicate that treatment induced cell wall disintegration and lysis. Results obtained on examination of antifungal activity of ZnO NPs reveal that significant photoinactivation (58%) of B. cinerea was observed at NPs concentration 5 × 10(-3)M and incubation time of 24h. SEM analysis confirmed that substantial morphological changes occur in the microfungus after treatment. The data suggest that ZnO NPs in the presence of visible light exhibit strong antibacterial and antifungal activity. Such ZnO NPs properties obviously could be used for the development of effective fungicides in agriculture or innovative physical antibacterial agents, so important in medicine and food microbial control.

Antibacterial and antifungal activity of photoactivated ZnO nanoparticles in suspension.

Photodynamic therapy is treatment modality involving the administration of photosensitizing compound, which selectively accumulates in the hyperproliferative target cells followed by local irradiation with visible light of lesion. Eventually target tissue will be damaged by necrosis and apoptosis. Action of treatment is described from absorption of light till damage of tissue. Several rationale proposals to increase the efficiency of described treatment modality are suggested: to evaluate the antiproliferative activity of new coming photosensitizers, to combine photosensitization with other treatment modalities in molecular level, exploring mechanism of apoptosis, to increase the efficiency of treatment by combination with ionizing radiation, hyperthermia or ligation of peripheral benzodiazepine receptors.

Photodynamic therapy: mechanism of action and ways to improve the efficiency of treatment.

Development of novel methods for decontamination of food and food-processing, food-handling environment, which are compatible with the consumer demand for minimally processed safe foods, remains one of the urgent topics of food science. One of these methods—antibacterial photosensitization-based treatment—is gaining more attention recently due to its unique properties. The method is based on combined action of nontoxic dye (called photosensitizer), visible light, and oxygen-producing cytotoxic effect (photodynamic effect). Presently, this method is widely used as anticancer and antiinfections treatments under the name photodynamic therapy. Photosensitization-based treatment was shown to be effective against a wide range of microorganisms (Gram-positive and Gram-negative bacteria in both vegetative form and spores, as well as in biofilms, mammalian viruses and bacteriophages, fungi and yeasts, and parasitic protozoa); no existing or emerging resistance against this treatment was observed even after multiple applications and the possibility of that is considered very unlikely; possibility to initiate the process on-spot and on-demand by targeted delivery of illumination provides multiple treatment options tailored to each particular case. Recent advances in the area of antibacterial photosensitization-based treatment applications in food and food-processing environment are presented in this review. Advantages and shortcomings of the method are discussed.

Antibacterial Photosensitization-Based Treatment for Food Safety

Aims: This study is focused on the possibility to control microbial contamination of strawberries by chlorophyllin (Na-Chl)-based photosensitization. Moreover, photosensitization-induced effects on key quality attributes of treated strawberries was evaluated.



Methods and Results:  Strawberries were inoculated with Listeria monocytogenes ATCL3C 7644, soaked in 1 mmol l−1 Na-Chl for 5 min and illuminated for 30 min with visible light (λ = 400 nm, energy density 12 mW cm−2). Results indicated that the decontamination of strawberries using photosensitization was 98% compared to control sample. Naturally occurring yeasts/microfungi and mesophiles were inhibited by 86 and 97%, respectively. The shelf life of treated strawberries was extended by 2 days. The total antioxidant activity of treated strawberries increased by 19%. No impact on the amount of phenols, anthocyanins or surface colour was detected.



Conclusions:  Photosensitization may be an effective, nonthermal and environmentally friendly microbial decontamination technique which expands the shelf life of strawberries without any negative impact on antioxidant activity, and phenols, anthocyanins or colour formation.



Significance and Impact of the Study:  Experimental data support the idea that Na-Chl-based photosensitization can be a useful tool for the future development of nonthermal food preservation technology.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2672.2011.04986.x

Novel approach to the microbial decontamination of strawberries: chlorophyllin-based photosensitization.

Photodynamic therapy (PDT) with endogenous protoporphyrin IX derived from 5-aminolevulinic acid or its derivatives has been established for treatments of several premalignancies and malignancies; however, the mechanism of the modality is not fully elucidated. The mitochondrial permeability transition pore consists mainly of the mitochondrial outer membrane voltage-dependent anion channel and the peripheral benzodiazepine receptor (PBR) and the mitochondrial inner membrane adenine nucleotide translocator (ANT). These mitochondrial proteins are responsible for the permeability transition that leads to apoptosis. In the present study, the human leukemia cell line, Reh, was treated with PDT using hexaminolevulinate (HAL). More than 80% of apoptotic Reh cells were found after HAL-mediated PDT (HAL-PDT) with high-molecular-weight (50 kbp) DNA fragmentation. Addition of PK11195 or Ro5-4864, two ligands of PBR, during HAL-PDT significantly inhibited the apoptotic effect. Bongkrekic acid, a ligand for ANT, also reduced the PDT effect. Although the mitochondrial transmembrane potential collapsed, neither cytosolic translocation of mitochondrial cytochrome c nor activation of caspase-9, caspase-8, caspase-3, and poly(ADP-ribose) polymerase were found. However, nuclear translocation of mitochondrial apoptosis-inducing factor (AIF) was shown by both immunoblotting and immunocytochemistry. Because AIF is the sole one among all proapoptotic factors involved in caspase-dependent and caspase-independent pathways that induces the high-molecular-weight DNA fragmentation, we conclude that HAL-PDT specifically targets PBR, leading to apoptosis of the Reh cells through nuclear translocation of mitochondrial AIF. This study suggests PBR as a possible novel therapeutic target for HAL-based PDT of cancer.

https://cancerres.aacrjournals.org/content/canres/65/23/11051.full.pdf

Targeting PBR by hexaminolevulinate-mediated photodynamic therapy induces apoptosis through translocation of apoptosis-inducing factor in human leukemia cells.

Zivile Luksiene

Papers

Antibacterial and antifungal activity of photoactivated ZnO nanoparticles in suspension.

Photodynamic therapy: mechanism of action and ways to improve the efficiency of treatment.

Antibacterial Photosensitization-Based Treatment for Food Safety

Novel approach to the microbial decontamination of strawberries: chlorophyllin-based photosensitization.

Targeting PBR by hexaminolevulinate-mediated photodynamic therapy induces apoptosis through translocation of apoptosis-inducing factor in human leukemia cells.