Targeted Photodynamic Therapy for Improved Lung Cancer Treatment

Cancer develops from the outgrowth of a clonal population of cells with a genetic pathology to evade cell death and exponential proliferation. It has become a global burden with increasing mortality rates. Lung cancer is a major contributor to cancer fatalities. Conventional therapies have shown advances in treating lung cancer, but the successful eradication of cancer lies in targeting both cancer and cancer stem cells. Cancer stem cells (CSCs) are a ration of cells found within the tumour bulk, capable of cancer initiation, therapy resistance, metastasis and cancer relapse. Photodynamic therapy (PDT) has proven effective in treating lung cancer. PDT exerts selective cell death mechanisms toward cancerous cells. With the use of a photosensitizer (PS) which becomes excited upon irradiation with laser light at a specific wavelength, the PS forms reactive oxygen species (ROS) in turn killing neoplastic cells. Leading therapeutic sequel can be obtained by transcending PDT though combination therapies such as immunotherapy and nanotechnology which will enable PDT to target lung CSCs preventing lung cancer recurrence

Laser therapy for the treatment of onychomycosis : best evidence based practice or not?

Abstract: Onychomycosis is a very common condition that accounts for 50% of all nail pathologies. Currently 2–5% of the world population suffers from this disorder. It is primarily caused by dermatophytes, but the infection can also be caused by yeasts and non-dermatophyte moulds. Onychomycosis is a therapeutic challenge and recently there has been an increase in resistance to oral and topical antifungal agents, leading to 20–25% relapse and/or reinfection rate. During the past 5 years, the emergence of laser therapy has been the topic of discussion as a newer, safer modality of treatment. Nail clippings and scrapings are the most common methods of sampling for suspected onychomycosis. The simplest method for detecting fungi is by way of 20% potassium hydroxide (KOH) preparations, but lately show insufficient sensitivity in onychomycosis – as much as 40–68%. Fungi can also be grown in culture form; however a 70% sensitivity detection failure rate is seen. Recently, histological fungal detection – in the form of Periodic Acid- Schiff (PAS) stain – has shown high sensitivity at 92% in the detection of fungal elements. The exact mechanism of action of laser is unknown but it is believed that heat disintegrates fungal structures. One of the most appealing characteristics of laser therapy is its ability to deliver energy to the target tissue and avoid systemic side effects at the same time. In 2009 the United Kingdom (UK) Podiatry magazine Podiatry Now published a letter suggesting laser treatment was “possibly the most radical development in the treatment of onychomycosis our profession has ever seen”, although concerns were raised over the unproven efficacy and investment costs involved. Papers have been published investigating the efficacy of lasers for the treatment of onychomycosis. Even though laser therapy provides an alternative option with rapid procedure duration, conflicting evidence is shown in a variety of papers and studies with longer follow-up periods suggest onychomycosis relapse in those treated with laser, which warrants further investigation

Low-level laser therapy for diabetic foot wound healing (Wound care)

An alternative to traditional treatment modalities for diabetic ulcers is low-level laser therapy (LLLT). A number of published studies demonstrate the beneficial effects of LLLT (Ribeiro et al, 2002), although several other studies also exist which indicate results to the contrary (Malm and Lundeberg, 1991; Loevschall and Arenholt-Bindslev, 1994). Further work focusing on cellular and molecular mechanisms of responses to laser irradiation is required to establish LLLT as a reliable, safe and inexpensive treatment modality. This article reviews LLLT as a treatment modality for diabetic ulcers

Neuronal differentiation of adipose derived stem cells: progress so far

Abstract: Please refer to full text to view abstrac

Targeted Photodynamic Therapy as Potential Treatment Modality for the Eradication of Colon Cancer

Photodynamic therapy (PDT) can be used to treat colorectal cancer (CRC). When a photosensitizer (PS) drug is administered to a patient, it can either passively or actively accumulate within a tumor site and once exposed to a specific wavelength of light, it is excited to produce reactive oxygen species (ROS), resulting in tumor destruction. However, the efficacy of ROS generation for tumor damage is highly dependent on the uptake of the PS in tumor cells. Thus, PS targeted uptake and delivery in CRC tumor cells is a crucial factor in PDT cancer drug absorption studies. Generally, within non-targeted drug delivery mechanisms, only minor amounts of PS passively accumulate in tumor sites and the remainder distributes into healthy tissues, causing unwanted side effects. To improve the efficacy of PDT research is currently focused on the development of specific receptor based photosynthetic nanocarrier platform drugs, which promote the active uptake and absorption of PS drugs in CRC tumor sites only, avoiding unwanted side effects, as well as treatment enhancement. This chapter will focus on current actively targeted PS nanoparticle drug delivery systems, which have been investigated for the PDT treatment of CRC cancer

Inorganic salts and antimicrobial photodynamic Therapy : mechanistic conundrums?

Abstract: We have recently discovered that the photodynamic action of many different photosensitizers (PSs) can be dramatically potentiated by addition of a solution containing a range of different inorganic salts. Most of these studies have centered around antimicrobial photodynamic inactivation that kills Gram-negative and Gram-positive bacteria in suspension. Addition of nontoxic water-soluble salts during illumination can kill up to six additional logs of bacterial cells (one million-fold improvement). The PSs investigated range from those that undergo mainly Type I photochemical mechanisms (electron transfer to produce superoxide, hydrogen peroxide, and hydroxyl radicals), such as phenothiazinium dyes, fullerenes, and titanium dioxide, to those that are mainly Type II (energy transfer to produce singlet oxygen), such as porphyrins, and Rose Bengal. At one extreme of the salts is sodium azide, that quenches singlet oxygen but can produce azide radicals (presumed to be highly reactive) via electron transfer from photoexcited phenothiazinium dyes. Potassium iodide is oxidized to molecular iodine by both Type I and Type II PSs, but may also form reactive iodine species. Potassium bromide is oxidized to hypobromite, but only by titanium dioxide photocatalysis (Type I). Potassium thiocyanate appears to require a mixture of Type I and Type II photochemistry to first produce sulfite, that can then form the sulfur trioxide radical anion. Potassium selenocyanate can react with either Type I or Type II (or indeed with other oxidizing agents) to produce the semi-stable selenocyanogen (SCN)2. Finally, sodium nitrite may react with either Type I or Type II PSs to produce peroxynitrate (again, semi-stable) that can kill bacteria and nitrate tyrosine. Many of these salts (except azide) are non-toxic, and may be clinically applicable

Cell death pathways and phthalocyanine as an efficient agent for photodynamic cancer therapy

Abstract: The mechanisms of cell death can be predetermined (programmed) or not and categorized into apoptotic, autophagic and necrotic pathways. The process of Hayflick limits completes the execution of death-related mechanisms. Reactive oxygen species (ROS) are associated with oxidative stress and subsequent cytodamage by oxidizing and degrading cell components. ROS are also involved in immune responses, where they stabilize and activate both hypoxia-inducible factors and phagocytic effectors. ROS production and presence enhance cytodamage and photodynamic-induced cell death. Photodynamic cancer therapy (PDT) uses non-toxic chemotherapeutic agents, photosensitizer (PS), to initiate a light-dependent and ROS-related cell death. Phthalocyanines (PCs) are third generation and stable PSs with improved photochemical abilities. They are effective inducers of cell death in various neoplastic models. The metallated PCs localize in critical cellular organelles and are better inducers of cell death than other previous generation PSs as they favor mainly apoptotic cell death events

Utilisation of targeted nanoparticle photosensitiser drug delivery systems for the enhancement of photodynamic therapy

Abstract: The cancer incidence world-wide has caused an increase in the demand for effective forms of treatment. One unconventional form of treatment for cancer is photodynamic therapy (PDT). PDT has 3 fundamental factors, namely a photosensitiser (PS) drug, light and oxygen. When a PS drug is administered to a patient, it can either passively or actively accumulate within a tumour site and once exposed to a specific wavelength of light, it is excited to produce reactive oxygen species (ROS), resulting in tumour destruction. However, the efficacy of ROS generation for tumour damage is highly dependent on the uptake of the PS in tumour cells. Thus, PS selective/targeted uptake and delivery in tumour cells is a crucial factor in PDT cancer drug absorption studies. Generally, within non-targeted drug delivery mechanisms, only minor amounts of PS are able to passively accumulate in tumour sites (due to the enhanced permeability and retention (EPR) effect) and the remainder distributes into healthy tissues, causing unwanted side effects and poor treatment prognosis. Thus, to improve the efficacy of PDT cancer treatment, research is currently focused on the development of specific receptor-based PS-nanocarrier platform drugs, which promote the active uptake and absorption of PS drugs in tumour sites only, avoiding unwanted side effects, as well as treatment enhancement. Therefore, the aim of this review paper is to focus on current actively targeted or passively delivered PS nanoparticle drug delivery systems, that have been previously investigated for the PDT treatment of cancer and so to deduce their overall efficacy and recent advancements

Regioselective synthesis of 1,5-disubstituted 1,2,3-triazoles by reusable AlCl₃ immobilized on ϒ-Aɭ₂O₃

Abstract: There is rapidly growing interest in the synthesis and use of substituted 1,2,3- triazoles. We report an easy and interesting procedure that demonstrates the effectiveness of surface-modified c-Al2O3, which is reusable, efficient, catalytic, safe, and environmentally acceptable for the regioselective synthesis of 1,5-disubstituted-1,2,3- triazoles via [3þ2] cycloaddition of phenyl and benzyl azides with a series of aryl nitroolefins in good yields. No adverse effect on substituents such as nitro, cyano, hydroxy, ether linkage, and halogens was observed. The catalyst could easily be recycled and was reused for nine runs without losing its activity

Photodynamic Therapy, a Potential Therapy for Improve Cancer Management

Cancer is a mass of abnormal and detrimental cells in a given part of the body. The main elucidated cause is the uncontrolled growth and proliferation of those cells after the corruption of the physiological processes responsible for normal development and functioning. The advantage of adjuvant therapy, therapy done after surgery, is to prevent the occurring of symptoms and not necessarily to make sure of the integrity of mechanisms that are crucial in preventing abnormal cell proliferation such cell cycle regulation, cell death, which include autophagy, necrosis, and apoptosis. The understanding of dysregulated cell death mechanisms combined with suitable alternative cancer therapies could lead to novel treatment modalities for cancer. Currently, breast cancer is the leading occurring cancer in sub-Saharan women after that of the cervix. This potentially curable condition kills more than half of the diagnosed group, which consists mainly of females aged between 35 and 49 years and with 77% being in stages III and IV. The social economic status of populations coupled with the limited access to proper control strategies and infrastructures in sub-Saharan regions accentuate the burden of the disease. Photodynamic therapy (PDT) has shown great potential in treating breast cancer and even greater therapeutic outcomes can be obtained when combining PDT with other therapies such as immunotherapy or nanomedicine