Blood Flow Changes In Transplantable Urothelial Tumors Treated With The Metallopurpurin, SnET2 And Light.

Selman, Steven H.; Qin, Binsheng; James, Harold R.; Keck, Rick W.; Garbo, Greta M.; Morgan, Alan R.

doi:10.1117/12.978001

Cited by 7 publications

(8 citation statements)

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“…Other authors (Kavarnos et al, 1994;Ma et al, 1993b;Berg et al, 1995) suggest that the variations observed in the interaction of PDT and ionizing radiation depend on dose and variation in timing between the two treatments. In vivo, photodynamic therapy is usually accompanied by severe microvascular changes (Nelson et al, 1987) associated with endothelial damage, microcirculatory stasis, platelet aggregation and haemorrhage, resulting in a coagulation necrosis (Bugelski et al, 1981;Selman et al, 1984;Star et al, 1986;Chaudhuri et al, 1987). These additional effects make it difficult to extrapolate in vitro studies on cell lines to the clinical situation where the combined approach of radiotherapy and photodynamic therapy may have quite different effectiveness than that presented in this study.…”

Section: Discussionmentioning

confidence: 81%

Effect of photodynamic therapy in combination with ionizing radiation on human squamous cell carcinoma cell lines of the head and neck

2000

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Photodynamic therapy (PDT) is a method for the treatment of cancer that involves the administration of systemic or topical photosensitizing drugs that are preferentially taken up by the tumour and then activated in the presence of light to cause tissue destruction (Dougherty, 1988). Photodynamic therapy works by the generation of singlet oxygen that results in damage to cell membrane structures, microvascular ischaemia, and tissue necrosis. Numerous clinical trials of photodynamic therapy have been conducted over the past decade and PDT has been approved for clinical use in recurrent bladder carcinomas, obstructing oesophageal tumours, and early carcinomas of the bladder, oesophagus, stomach, and tracheobronchial tree. PDT has also been shown to provide curative treatment of early carcinomas of the head and neck, including the oral cavity, pharynx, and larynx (Biel, 1995;Feyh, 1996). Initially PDT was tested in advanced cancers of the head and neck that were untreatable or refractory to conventional therapy, however these trials produced only limited success (Schuller et al, 1984;Wile et al, 1984). A recent retrospective review of the clinical data available for the treatment of head and neck neoplasia using photodynamic therapy indicated that complete response rates of 89.5% are achievable for early squamous cell carcinoma of the head and neck (Biel, 1998). Based on a range of photosensitizers and treatment modalities, cure rates of 95% and 80% were obtained for carcinoma in situ and T1 squamous cell carcinoma of the vocal chord and oral cavity/tongue respectively (follow up 70 months) (Biel, 1998).Most of the available photosensitizers, until recently, have been mixtures of porphyrins such as haematoporphyrin derivative and Photofrin (Quadralogic Technologies, Vancouver, Canada). The main problem with these first-generation photosensitizers is that of prolonged skin photosensitivity. Phototoxic incidences of 20-40% have been reported during follow-up of patients having received Photofrin, with a mean duration of skin photosensitivity exceeding 6 weeks (Dougherty et al, 1990).The use of 5-aminolaevulinic acid (ALA) represents a different strategy in the administration of photosensitizers. ALA itself is not the photo-active drug, but rather it induces, in situ, the synthesis of a pure endogenous porphyrin called protoporphyrin IX (PpIX). The formation of PpIX forms part of the haem synthesis pathway and all nucleated cells that use oxidative metabolism are probably capable of forming this photosensitizer. However, malignant tissue appears to preferentially accumulate PpIX, forming the basis of photodynamic therapy in cancer (Battle, 1993;Kennedy and Pottier, 1994). Intravenous ALA is rapidly cleared from the body, with no PpIX fluorescence within the skin or other body organs detectable after 24 h (Kennedy et al, 1991).Because of this reduced phototoxicity and excellent tumour localizing properties, ALA has been used with great success for the treatment of several neoplastic diseases, particularly of the skin, b...

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Section: Discussionmentioning

confidence: 81%

Effect of photodynamic therapy in combination with ionizing radiation on human squamous cell carcinoma cell lines of the head and neck

2000

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“…The presence of molecular oxygen is mandatory for the photodynamic process to occur, as cytotoxicity and subsequent tissue destruction requires a transfer of energy from the excited photosensitizer molecule to singlet oxygen, followed by interaction with the biological substrate (Moan et al, 1979;MacRobert et al, 1989). Photodynamic therapy is usually accompanied in vivo by severe microvascular changes (Nelson et al, 1987) associated with endothelial damage, microcirculatory stasis, platelet aggregation and haemorrhage, resulting in a coagulation necrosis (Bugelski et al, 1981;Selman et al, 1984;Star et al, 1986;Chaudhuri et al, 1987). A distinct advantage of using ALA to generate PpIX as an in situ photosensitizer is the relatively rapid clearance of photoactive substances from the body.…”

Section: Discussionmentioning

confidence: 99%

Effect of photodynamic therapy in combination with mitomycin C on a mitomycin-resistant bladder cancer cell line

Datta

Allman²,

Loh³

et al. 1997

Br J Cancer

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Summary Photodynamic therapy is a method for treating cancer using drugs activated by light. A new compound, 5-aminolaevulinic acid (ALA), is a precursor of the active photosensitizer protoporphyrin IX (PpIX) and has fewer side-effects and much more transient phototoxicity than previous photosensitizers. Cell survival of ALA-mediated photodynamic therapy was measured in the J82 bladder cancer cell line, along with its mitomycin C-resistant counterpart J82/MMC. This demonstrated that mitomycin resistance is not cross-resistant to photodynamic therapy. There was also a suggestion that the mitomycin-resistant cells were more susceptible to photodynamic therapy than the parent cell line. Photodynamic therapy appeared to enhance the effect of mitomycin C, when mitomycin C was given first. This phenomenon was apparent for both drug-resistant and drug-sensitive cell lines. This suggests a possible role for combined mitomycin C and photodynamic therapy in superficial bladder tumours that have recurred despite intravesical cytotoxic drug treatment.

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“…Cells from murine tumours remaining in situ after PDT undergo necrosis, whereas those explanted immediately after photoactivation remain viable in vitro, suggesting that local tissue factors may play an important role (Henderson et al, 1985). Blood flow changes resulting from PDT were first quantified by Selman et al (1984) in transplantable bladder tumours treated with HPD (lIOgg-1) and red light (630 J cm-2). Using a radioactive microsphere technique they demonstrated a significant reduction in blood flow to tumours 10min and 24 h after the end of photoactivation.…”

Section: Discs_shmentioning

confidence: 99%

The effect of aminolaevulinic acid-induced, protoporphyrin IX-mediated photodynamic therapy on the cremaster muscle microcirculation in vivo

Leveckis

Brown²,

Reed³

1995

Br J Cancer

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SummaryThe effect of photodynamic therapy on normal striated muscle was investigated using 30 adult male rats. Animals were divided into six groups. Three control groups received phosphate-buffered saline by gavage and violet light at 105. 178 and 300 mW cm -' respectively. Three experimental groups received aminolaevulinic acid (ALA: 200mg kg -') and violet hght at 105. 178 and 300 mW cm--respectively. After exposure of the cremaster muscle animals were allowed to equilibrate and vessel diameters and bloodflow assessed. Following photoactivation measurements were taken every 10 min over a 2 h penrod. Photoactivation of expenrmental groups at the two higher power densities resulted in an initial decrease in both artenrolar and venular diameters, and a concomitant decrease in blood flow. The magnitude of these changes and the degree of recovery by the end of the observation period was related to power density. No effects were observed in the control groups. These results suggest that microcirculatory damage may contribute to the mechanism of action of photodynamic therapy with ALA.

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Blood Flow Changes In Transplantable Urothelial Tumors Treated With The Metallopurpurin, SnET2 And Light.

Cited by 7 publications

References 0 publications

Effect of photodynamic therapy in combination with ionizing radiation on human squamous cell carcinoma cell lines of the head and neck

Effect of photodynamic therapy in combination with ionizing radiation on human squamous cell carcinoma cell lines of the head and neck

Effect of photodynamic therapy in combination with mitomycin C on a mitomycin-resistant bladder cancer cell line

The effect of aminolaevulinic acid-induced, protoporphyrin IX-mediated photodynamic therapy on the cremaster muscle microcirculation in vivo

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