Inhibition of retrovirus-induced syncytium formation by photoproducts of a brominated 1,8-naphthalimide compound

Chanh, Tran C.; Lewis, David E.; Judy, Millard M.; Sogandares-Bernal, Franklin; Michalek, Glenn R.; Utecht, Ronald E.; Skiles, Helen; Chang, Shao-Chieh; Matthews, James L.

doi:10.1016/0166-3542(94)90102-3

Cited by 35 publications

(17 citation statements)

References 14 publications

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“…In this respect, Photofrin II (6), which yields significantly high amounts of 1 O 2 upon light exposure, has been successfully preactivated (71); however, the reactive intermediates have yet to be identified. Similarly, another photosensitizer, naphthalimide, has been reported to generate reactive photoproducts with anti-viral activity in cells infected with HIV or HTLV-1 (72). More recently, our preliminary data strongly support a similar mechanism for another potential photodynamic agent, hypericin (St. John's wort) (73,74).…”

Section: Discussionsupporting

confidence: 75%

Reactive oxygen‐dependent production of novel photochemotherapeutic agents

Pervaiz

2001

FASEB j.

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The reactive nature of species derived from oxygen, such as singlet oxygen and hydrogen peroxide, has been exploited in the clinical setting for targeting bacteria, viruses, and tumor cells by photodynamic excitation of a variety of chromophores. This modality, termed photodynamic therapy (PDT), is currently being used to treat some forms of cancer. However, the applicability of conventional PDT is limited due to the absolute dependence on simultaneous exposure of the target to the photoactive compound and light. In 1990, we demonstrated that the need for simultaneous exposure of the biological target to light and photosensitizer could be circumvented by prior exposure (activation) of the sensitizer molecule to light and its subsequent use as any other anti-cancer or anti-viral drug. By dint of the nature of the protocol, this process was termed preactivation. Since then, the generation of biologically active molecules in vitro by preactivation has been validated using a variety of chromophores, such as merocyanine 540, Photofrin II, and naphthalimide. Here we briefly review the role of reactive oxygen species in the photodynamic effect, and provide an explanation for the mechanism of preactivation. We propose that photo-oxidation not only provides a novel means for the generation of biologically active molecules, but could also explain, at least in part the mechanism of conventional PDT. It is likely that the light-dependent breakdown of the chromophore to generate novel active compounds, in addition to reactive oxygen species, also contributes to the photodynamic damage observed on simultaneous exposure of the chromophore and target tissue to light during PDT.-Pervaiz, S. Reactive oxygen-dependent production of novel photochemotherapeutic agents.

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Section: Discussionsupporting

confidence: 75%

Reactive oxygen‐dependent production of novel photochemotherapeutic agents

Pervaiz

2001

FASEB j.

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“…Most certainly not! This phenomenon of light activation to generate biologically active molecules has also been demonstrated with photofrin II and naphthalimide 59,60 . These findings suggest a possible common mechanism applicable to some chromophores, whereby exposure to light results in the generation of novel small molecules with potential for use as systemic agents without further dependence on light.…”

Section: Photo‐activation: Modality For Generating Novel Small Moleculesmentioning

confidence: 55%

“…This phenomenon of light activation to generate biologically active molecules has also been demonstrated with photofrin II and naphthalimide. 59,60 These findings suggest a possible common mechanism applicable to some chromophores, whereby exposure to light results in the generation of novel small molecules with potential for use as systemic agents without further dependence on light. Furthermore, photo-oxidation not only provides a novel means for generating new molecules, but the identification of breakdown products could also explain the mechanism of conventional PDT.…”

Section: Photo-activation: Modality For Generating Novel Small Moleculesmentioning

confidence: 92%

Art and Science of Photodynamic Therapy

Pervaiz

Olivo

2006

Clin Exp Pharma Physio

133

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4. Light sources have moved from the use of white light with specific filters in the old days to the more recent use of monochromatic light sources, such as lasers, to more sophisticated light-emitting diodes. However, dosimetry remains a big issue mainly because of difficulties in establishing the optimum treatment conditions for an approach that requires the finetuning of several variables, such as sensitizer and light doses and drug-to-light interval, as well as the issues of skin photosensitivity and low selectivity. A newer development to circumvent these and provide a broader application for this concept has been the phenomenon of photo-activation, whereby photo-exposure of chromophores to generate novel, small biologically active compounds has been demonstrated successfully.5. The aim of the present review was to provide a general overview of the art and science of photodynamic therapy and to highlight some of the issues and recent developments in further advancing this modality of treatment.

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“…With a view to the commonly observed fluorescence quenching action of transition metal ions to various fluorophores, [74,75] it is obvious that in order to serve the purpose of fluorescence enhancement induced by transition metal ions, specifically designed molecular systems are required in which the receptor when bound to the metal ions will be inaccessible to the fluorophore for quenching. Few such successes have been reported where a cryptand receptor has been employed to trap the metal ion in its cavity so as to suppress the quenching activity [76][77][78][79]. In the present study, our target molecule, NBHN32 has a relatively simpler molecular structure but is found to undergo notable fluorescence enhancement in the presence of transition metal ions.…”

Section: Mechanism Of Intensity Enhancementmentioning

confidence: 91%