Photodynamic therapy for photochemists.

Philos Trans A Math Phys Eng Sci. 2013;371(1995):20120371

Authors: Bown SG

Abstract
Photodynamic therapy (PDT) is an evolving technique for localized control of diseased tissue with light after prior administration of a photosensitizing agent and in the presence of oxygen. The biological effect is quite different from surgery, radiotherapy and chemotherapy. With no temperature change during treatment, connective tissues like collagen are largely unaffected, so maintaining the mechanical integrity of hollow organs. PDT is of particular value for pre-cancer and early cancers of the skin (not melanomas) and mouth as the cosmetic and functional results are so good. Another key indication is for small areas of cancer that are unsuitable for or have persisted or recurred after conventional management. It can be applied in areas already exposed to the maximum safe dose of radiotherapy. Outside cancer, in ophthalmology, it is established for age-related macular degeneration, and has considerable potential in arterial disease for preventing restenosis after balloon angioplasty and in the treatment of infectious diseases, where the responsible organisms are accessible to both the photosensitizer and light. New developments on the horizon include techniques for increasing the selectivity for cancers, such as coupling photosensitizers to antibodies, and for stimulating immunological responses, but many further pre-clinical and clinical studies are needed to establish PDT's role in routine clinical practice.

PMID: 23776302 [PubMed - in process]

Related Articles

Strategies of airway management for head and neck photo-dynamic therapy.

Lasers Surg Med. 2013 Jun 15;

Authors: Story W, Sultan AA, Bottini G, Vaz F, Lee G, Hopper C

Abstract
INTRODUCTION: Photodynamic therapy (PDT) is a minimally invasive treatment modality, which has great clinical implications, especially in head and neck oncology. Post-operative swelling is a well-documented consequence of PDT. It is paramount the airway remains patent for these patients. A tracheostomy remains the gold standard treatment modality for base of tongue tumours susceptible to post operative PDT inflammation, which can lead to a compromised airway. We have carried out a retrospective study to outline the airway management strategies employed for head and neck cancer patients treated with PDT and suggest recommendations for future management. MATERIALS AND METHODS: This retrospective clinical study utilises 88 patients (53 males and 35 females) treated at the UCLH Head and Neck Center, London (between 2006 and 2013), for treatment of various lesions with superficial and/or interstitial PDT, when the airway could potentially be compromised. RESULTS: Of the 88 patients selected 60 had interstitial PDT (iPDT) and 13 had superficial PDT (sPDT). Fifteen patients were treated with both iPDT and sPDT. Among the iPDT patients 19 had a trachestomy; two patients a Quicktrach; four a Cook Airway Exchange Catheter (CEAC); one a percutaneous tracheostomy; one a needle tracheostomy and 33 patients did not receive any temporary airway pathways. Among the sPDT patients two had a trachestomy. Although the majority of patients did not suffer any major incidents, one sPDT patient required an emergency tracheostomy 2 days post-operatively. CONCLUSION: Airway management is vital when planning PDT treatment for tongue based tumours. Consider a more conventional approach when the lesion being targeted is located at a higher risk site: Floor of mouth/posterior tongue/tongue base or when multiple oral sites are being treated. Lasers Surg. Med. 9999:1-7, 2013. © 2013 Wiley Periodicals, Inc.

PMID: 23775429 [PubMed - as supplied by publisher]

Incidence and Main Risk Factors for Severe Retinopathy of Prematurity in Infants Weighing Less Than 1000 Grams in Brazil.

J Trop Pediatr. 2013 Jun 14;

Authors: Fortes Filho JB, Borges Fortes BG, Tartarella MB, Procianoy RS

Abstract
Objectives: This study evaluated the incidence and risk factors for severe retinopathy of prematurity (ROP) in babies <1000 g at Porto Alegre, Brazil.Methods: Prospective cohort study including premature children with birth weight ≤1000 g was conducted. Main outcome was the occurrence of severe ROP needing treatment.Results: A total of 157 infants were included. Severe ROP occurred in 20 infants (12.7%). Nineteen patients were treated by laser photocoagulation. Main risk factors for severe ROP were gestational age (P = 0.029), infant's weight measured at sixth week of life (P < 0.001) and number of days of oxygen therapy under mechanical ventilation (P < 0.001). After logistic regression, infant's weight at sixth week of life and number of days in mechanical ventilation were associated to severe ROP.Conclusions: We reported the incidence of 12.7% of severe ROP among babies born ≤ 1000 g in our institution. Laser photocoagulation was effective to stabilize the disease among 19 treated patients.

PMID: 23771954 [PubMed - as supplied by publisher]

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Topological insulator bismuth selenide as a theranostic platform for simultaneous cancer imaging and therapy.

Sci Rep. 2013 Jun 17;3:1998

Authors: Li J, Jiang F, Yang B, Song XR, Liu Y, Yang HH, Cao DR, Shi WR, Chen GN

Abstract
Employing theranostic nanoparticles, which combine both therapeutic and diagnostic capabilities in one dose, has promise to propel the biomedical field toward personalized medicine. Here we investigate the theranostic properties of topological insulator bismuth selenide (Bi2Se3) in in vivo and in vitro system for the first time. We show that Bi2Se3 nanoplates can absorb near-infrared (NIR) laser light and effectively convert laser energy into heat. Such photothermal conversion property may be due to the unique physical properties of topological insulators. Furthermore, localized and irreversible photothermal ablation of tumors in the mouse model is successfully achieved by using Bi2Se3 nanoplates and NIR laser irradiation. In addition, we also demonstrate that Bi2Se3 nanoplates exhibit strong X-ray attenuation and can be utilized for enhanced X-ray computed tomography imaging of tumor tissue in vivo. This study highlights Bi2Se3 nanoplates could serve as a promising platform for cancer diagnosis and therapy.

PMID: 23770650 [PubMed - in process]

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Comparing endovenous laser ablation, foam sclerotherapy, and conventional surgery for great saphenous varicose veins.

J Vasc Surg. 2013 Jun 12;

Authors: Biemans AA, Kockaert M, Akkersdijk GP, van den Bos RR, de Maeseneer MG, Cuypers P, Stijnen T, Neumann MH, Nijsten T

Abstract
BACKGROUND: Many case series have been published on treatments of varicose veins, but comparative randomized controlled trials remain sparse. OBJECTIVE: To compare the anatomic success rate, frequency of major complications, and quality-of-life improvement of endovenous laser ablation (EVLA), ultrasound-guided foam sclerotherapy (UGFS), and conventional surgery (CS), after 1-year follow-up. METHODS: A total of 240 consecutive patients with primary symptomatic great saphenous vein reflux were randomized to EVLA, UGFS, or CS, consisting of high ligation and short stripping. Primary outcome was anatomic success defined as obliteration or absence of the treated vein on ultrasound examination after 1 year. Secondary outcomes were complications, improvement of the "C" class of the CEAP classification, and improvement of disease-specific (Chronic Venous Insufficiency Quality-of-Life Questionnaire) and general (EuroQol 5) quality-of-life scores. RESULTS: More than 80% of the study population was classified as C2 or C3 venous disease. After 1 year, the anatomic success rate was highest after EVLA (88.5%), followed by CS (88.2%) and UGFS (72.2%) (P < .001). The complication rate was low and comparable between treatment groups. All groups showed significant (P < .001) improvement of EuroQol 5 and Chronic Venous Insufficiency Quality-of-Life Questionnaire scores after therapy; 84.3% of all treated patients showed an improvement of the "C" of the CEAP classification. CONCLUSION: After 1-year follow-up, EVLA is as effective as CS and superior to UGFS according to occlusion on ultrasound duplex. Quality of life improves after treatment in all groups significantly.

PMID: 23769603 [PubMed - as supplied by publisher]

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Non-ablative fractional resurfacing in combination with topical tretinoin cream as a field treatment modality for multiple actinic keratosis: a pilot study and a review of other field treatment modalities.

J Dermatolog Treat. 2013 Jun;24(3):227-31

Authors: Prens SP, de Vries K, Neumann HA, Prens EP

Abstract
BACKGROUND: Actinic keratoses (AK) are premalignant lesions occurring mainly in sun-damaged skin. Current topical treatment options for AK and photo-damaged skin such as liquid nitrogen and electrosurgery are not suitable for field treatment. Otherwise, therapies suitable for field treatment bring along considerable patient discomfort. Non-ablative fractional resurfacing has emerged as a logical treatment option especially for field treatment of AK.
OBJECTIVES: To evaluate the clinical efficacy of fractional laser therapy for clearing AK and improving skin quality. To compare patient friendliness of the "fractional" therapy with those reported for other field treatment modalities.
MATERIALS & METHODS: Ten patients with Fitzpatrick skin type I to III with multiple AK and extensive sun-damaged skin, received 5-10 sessions with a 4-week interval using a 1550 nm Erbium-Glass Fractionated laser (Sellas, Korea). Four weeks and 24 weeks after the last treatment the clinical results were evaluated by an independent physician.
RESULTS: The mean degree of improvement, in terms of reduction in the number of AK and improvement of skin texture, was 54% on a 4 point PGA scale, and persisted for approximately 6 months. The biggest advantage of fractional laser treatment, besides the eradication of AK and a clear rejuvenation effect, is the absence of "downtime".
CONCLUSION: Fractional non-ablative resurfacing induces significant reduction in the number of AK and improves the skin quality. Also all patients preferred fractional laser therapy above other AK treatment modalities.

PMID: 22515664 [PubMed - indexed for MEDLINE]