PPS Blog

Nils Ryberg Finsen (1860–1904) (Courtesy of the Clendening History of Medicine Library, University of Kansas Medical Center

“Real modern phototherapy began with Niels Ryberg Finsen, the father of ultraviolet therapy. In 1896, Finsen, aware of the bacteria-destroying effects of sunlight, developed a “chemical rays” lamp with which he treated a friend who had lupus vulgaris; within a few months the lesions were completely resolved”

This perspective by Herbert Hönigsmann from the Department of Dermatology from the Medical University of Vienna gives a history of phototherapy in dermatology, describing the key developments to date.  He covers the ancient history and describes how over many centuries, treatment with sunlight or “heliotherapy” was used in the treatment of skin diseases.  He then describes the developments made in the 19^th century when observations were made that sunlight may be beneficial for medical purposes. 

In 1974 the development of photochemotherapy marked the beginning of a huge upsurge in photodermatology and the subsequent development of high intensity UV sources with defined spectra facilitated a variety of new therapies. Photodynamic therapy, first conceived at the start of the 20^th century has developed in to a routine treatment for many diseases including cancer.

The parting words of this article come from a quote from Kendric C. Smith, one of the founding fathers of the American Society for Photobioloty: “Photodermatology – The future is Bright”.

Read the article in full, free to access until 10th August:

History of phototherapy in dermatology, Herbert Hönigsmann
Photochem. Photobiol. Sci., 2012, Advance Article, DOI: 10.1039/C2PP25120E

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Naphthalenic compunds have many applications in the fluorescent sensing/switching/logic systems.  In this paper from A. Prasanna de Silva and colleagues at Queen’s University in Belfast, the team examine a naphthalenic compund which is a fluorescent photoinduced electron transfer system of the ‘fluorophore-spacer-receptor’ format, whose fluorescence responds sharply to H⁺. Several structural variations of this compund are examined and it is deomonstrated that the naphthalenic derivatives display a range of H⁺-induced fluorescence switching actions.

For all the details read the article in full for free until 31^st July:

Structural effects on the pH-dependent fluorescence of naphthalenic derivatives and consequences for sensing/switching
Shuai Zheng, P. L. Mark Lynch, Terence E. Rice, Thomas S. Moody, H. Q. Nimal Gunaratne and A. Prasanna de Silva
Photochem. Photobiol. Sci., 2012, Advance Article, DOI: 10.1039/C2PP25069A

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The photocatalytic inactivation of influenza virus using titanium dioxide thin film is demonstrated in a recently published paper from Ryuichi Nakano and co-workers from Japan.  Titanium dioxide (TiO₂) under ultraviolet (UV) light produces a strong oxidative effect and may therefore be used as a photocatalytic disinfectant.  Photocatalytic inactivation of bacteria is well known, however few studies have addressed virus inactivation. 

In this paper the inactivation of influenza virus is demonstrated using TiO₂ nanoparticles immobilized on a glass plate.  Viral titers were dramatically reduced by the photocatalytic reaction and the influence of UV intensity, irradiation time and bovine serum albumin concentration in viral suspensions was investigated.  It was demonstrated that effective inactivation occurs under an environmental level of UV-A intensity.  In addition, the International Organization for Standardization (ISO) methodology for anti-bacterial effects of TiO₂ photocatalysis can be useful for the evaluation of antiviral activity with only a small modification to the methodology.

Interested in knowing more?  Read the full article for free until June 14^th by clicking the link below!

Photocatalytic inactivation of influenza virus by titanium dioxide thin film
Ryuichi Nakano, Hitoshi Ishiguro, Yanyan Yao, Jitsuo Kajioka, Akira Fujishima, Kayano Sunada, Masafumi Minoshima, Kazuhito Hashimoto and Yoshinobu Kubota
Photochem. Photobiol. Sci., 2012, DOI: 10.1039/C2PP05414K

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In this communication recently published online as an ‘Accepted Manuscript’ Frederick Lewis and co-workers from the USA and India investigate the effect of flanking purine bases on the 3’ vs the 5’-TT dimer upon UV irradiation of DNA hairpins possessing TTT steps with flanking purine bases. 

The study demonstrates moderate to high facial selectivity for the 3’-dimer over the 5’ dimer depending on the identity and location of flanking purine bases.  The effects of flanking purines on facial selectivity are attributed to a combination of their ground state conformational effects and electron transfer quenching.

Interested in knowing more? Read the full article for free until June 13th.

Facially-Selective Thymine-Thymine Photodimerization in TTT Triads
Prakash P Neelakandan, Zhengzheng Pan, Mahesh Hariharan and Frederick D Lewis
Photochem. Photobiol. Sci., 2012, Accepted Manuscript, DOI: 10.1039/C2PP25089F

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