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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The effectiveness of the photodynamic action of porphyrins, was studied by means of the tissue explant culture technique. A murine tumor tissue explant was incubated in a medium containing 0.6 mM of ALA for periods of 1 and 2 hr; total porphyrins synthesized under these conditions were of the same level as those found in our previous in vivo experiments. The explants were then irradiated for 30 min with He-Ne laser of 3.5 mW output power placed at a distance of 10 cm. Controls of non-irradiated tumor tissue slices incubated with and without ALA were performed. Immediately after irradiation, inocula of exactly 1 mm3 of the irradiated and non-irradiated tissue were subcutaneously injected under the right and left flanks of the same animal, respectively. The growth of the tumor was measured 15, 20 and 25 days after implantation. 2. Results obtained showed that the explants that were incubated for 1 hr with ALA and irradiated, reaching a concentration of 2.8 micrograms porphyrins/g tissue, produced a reduction of 50-70% of tumor size as compared with the non-irradiated controls incubated with ALA. Explants incubated for 2 hr, reaching a concentration of 4.6 micrograms porphyrins/g tissue, produced from 60% to complete lack of tumor growth. The effectiveness index (EI) of photoirradiation was calculated on the basis of the tumor growth in irradiated and non-irradiated tumors. EI was nearly 100% showing almost complete tumor cell destruction for tumor irradiated for 2 hr with 0.6 mM ALA.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Photodynamic action of endogenously synthesized porphyrins from aminolevulinic acid, using a new model for assaying the effectiveness of tumoral cell killing. 822 54

delta-Aminolevulinic acid (ALA) causes cells to accumulate protoporphyrin IX (Proto) and heme. Exposure to light in vitro causes intracellular Proto to initiate formation of singlet oxygen molecules, leading to self-destruction. This photoactivated destruction by ALA in vitro is enhanced by addition of the tetrapyrrole modulator 1,10-phenanthroline (Oph), which increases cellular accumulation of Proto. Here we significantly extend this idea by evaluating the efficacy of ALA and Oph photodynamic therapy of solid tumors in vivo. Methylcholanthrene-induced fibrosarcoma (Meth-A) cells were used, which lead to the formation of solid tumors when implanted into syngeneic recipients. Initially, suspensions of Meth-A cells were treated in vitro with combinations of ALA and Oph. Meth-A cells in suspension accumulated 6-fold greater amounts of Proto (P < 0.05) after 3-h incubation with ALA and Oph than when incubated with ALA alone, and were also more susceptible to subsequent photoactivated cell lysis in vitro. Similarly, solid Meth-A tumors grown in syngeneic BALB/c mice accumulated significant (P < 0.05) amounts of Proto 3 h after in vivo treatment with ALA, and Oph synergized with ALA to significantly (P < 0.05) enhance the induction of Proto in these tumors. ALA and Oph-based phototreatment of mice bearing Meth-A solid tumors resulted in necrosis of tumors, as determined by a significant reduction in both size and histopathology, with little damage to surrounding normal tissue. These data directly demonstrate the experimental usefulness of Proto modulators for ALA-based photodynamic therapy in the treatment of solid tumors in vivo and provide a rationale for their potential application in a multitude of tumor types.
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PMID:Induction of tumor necrosis by delta-aminolevulinic acid and 1,10-phenanthroline photodynamic therapy. 854 89

Photodynamic therapy is achieved by a photodynamic reaction which is induced by excitation of photosensitizer exposed to light. This phenomenon was first reported by Raab et al in 1990. In 1960 Lipson et al reported hematoporphyrin derivative (HpD) by treating hematoporphyrin chloride with hydrochloric acid and sulfuric acid. The development of HpD established the basis of today's photodynamic therapy (PDT). Dougherty reported the treatment of skin tumors by PDT first with an argon dye laser in 1978. The author and his colleagues began basic studies of this treatment using HpD supplied by Dougherty and argon dye laser in canine lung cancer in 1978. These studies confirmed the effectiveness and safety of the method. Bronchofiberscopic PDT for early stage central type squamous cell carcinoma was performed by the authors in 1980 for the first time in the world and complete cure was obtained. Since then PDT has been attracted much attention. The photosensitizer and the laser with a specific wavelength are the key point of PDT. Photofrin, a porfimer sodium (Japan Lederle Co. Ltd., Tokyo, Japan) and excimer dye laser (Hamamatsu Photonics Co. Ltd., Hamamatsu, Japan) obtained governmental approval for clinical use in Japan in 1994, which is equivalent to FDA approval in the US. This method is now used clinically in Canada for certain indications and the Netherlands. In the US it is only approved for compassionate use in cancer of the esophagus. A total of more than 3,000 tumors in the various organs have been treated by PDT so far in 32 countries. The most frequently treated organ is the lung, with 808 cases. A phase II clinical study of PDT for early stage cancer cases of the lung, esophagus, stomach, cervix and urinary bladder was performed in 15 institutions from 1989 to early 1992. The results showed that PDT can successfully treat more than at least 50% of patients with early stage cancer cancer that would otherwise have to be treated by surgery and this means that PDT can contribute to their QOL. The cost effectiveness of PDT versus operation was estimated by the calculation based on QALY's (Quality Adjusted Life Year's saved) by Fujino of the Economics Department of Chuo University. According to this calculation PDT was estimated to be at least 30 percent less than the cost of operation. PDT is indicated in cases with superficial localized early stage lung cancer as a curative treatment and as a palliative treatment for opening stenotic or obstructed bronchi due to tumor prior to the combination therapy with surgery. Recent studies on photodynamic therapy (PDT) began just two decades ago, therefore there are still a large number of unsolved problems. However PDT will have many applications in a wide range of fields from preclinical to clinical medical science. In lung cancer, the indications will be extended for early stage lung cancer and improvement of therapeutic results will be achieved by the development of new photosensitizers such as chlorin, pheophorbide, phthalocyanin, ALA, benzoporphyrin, etc which can be excited by longer wavelength and new lasers such as pulsed excimer dye, YAG-OPO and diode lasers. Through these new developments the indications of this treatment for malignant will continue to expand.
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PMID:[History of photodynamic therapy--past, present and future]. 854 74

The aim of this study was to evaluate 5-Aminolevulinic acid (ALA)-induced fluorescence of normal and neoplastic endometrial epithelial cells for diagnosis and photodynamic treatment. Fluorescence of ALA-induced PpIX in vitro was measured by flow cytometry in two different human endometrial adenocarcinoma cell lines and in normal cells cultivated from fresh endometrial tissue of three premenopausal patients. The cells were analysed after incubation with different concentrations of ALA during 3, 6, or 24 hours. Both tumor cell lines showed a statistically significant higher fluorescence of PpIX than normal epithelial cells after incubation with 1 mg ALA per ml medium during 24 hours. The well-differentiated cancer cells produced significantly more PpIX than the poorly differentiated cancer cells. Relative PpIX intensity of the two cancer cell lines correlated with cell proliferation rate as measured by the doubling times of the cells. Higher accumulation of Pp IX in neoplastic endometrium compared to normal endometrial epithelial cells may provide targeted biopsies and selective photodynamic destruction of neoplastic micro-lesions.
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PMID:Accumulation of 5-aminolevulinic acid-induced protoporphyrin IX in normal and neoplastic human endometrial epithelial cells. 871 29

We treated a large superficial basal cell carcinoma (ca. 10 x 6 cm) on the right breast in a 48-year old woman with photodynamic therapy (PDT). Fractionated PDT was performed by topical application of delta-aminolevulinic acid (delta-ALA, 20%) with subsequent red light (570-750 nm; 180 J/ cm2) in three sessions. Nearly total remission of the tumor resulted; however, a few residual neoplastic islands partly infiltrating the nipple-areola complex could be detected by photodynamic diagnosis (PDD). These fluorescent areas were marked, excised, and the defect was closed by a rotation advancement flap. Total excision of the tumor was verified histologically. By combining PDT and surgery, this large tumor was treated with excellent cosmetic results. This case demonstrates the efficiency of topical PDT with adjunctive plastic surgery controlled by PDD even in large tumors.
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PMID:[Photodynamic therapy and breast-plasty of a extensive superficial trunk skin basalioma of the breast. An effective combination therapy with photodynamic diagnosis]. 876 58

A new concept in photosensitizing tumor cells is photosensitizer synthesis in situ. Aminolevulinic acid (ALA) is a precursor of protoporphyrin IX (PP IX), a potent photosensitizer. The goal of our study was to examine dark toxicity, phototoxic potential, metabolism of ALA and morphological alterations in Waf bladder cancer cells. Dark toxicity of Waf cells was observed after incubation with ALA, beginning at a concentration of 15 mM. Photodynamic treatment with ALA at concentrations of 1, 5 and 10 mM showed a drug- and light-dose-dependent cell survival rate in comparison to a control group. Two incubation times of 3.5 and 5.5 h were compared for cell survival. After a longer incubation time of 5.5 h, cell survival was decreased in all experiments; this is consistent with our extraction data where higher fluorescence was found after 5.5 than after 3.5 h. The results show that ALA-induced photosensitization has a high potential for photodynamic therapy (PDT) of superficial bladder carcinoma.
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PMID:Aminolevulinic acid for photodynamic therapy of bladder carcinoma cells. 893 Dec 93

Photodynamic therapy (PDT), a novel treatment for a variety of human malignancies, usually consists of visible light irradiation of lesions following the systemic administration of a photosensitizer. Induction of the endogenous photosensitizer protoporphyrin IX by the systemic or topical administration of delta-aminolevulinic acid (delta-ALA) is being investigated for use in PDT. We have determined that the incubation of two human and two rodent tumor cell lines in culture with delta-ALA over a 24 h period results in an increase in the accumulation of fluorescent porphyrins in all of these cell lines. However, the two human cell lines produce fluorescent porphyrin at different rates from those seen in the rodent cell lines. The uptake of 14C-delta-ALA was concentration dependent, similar for all the cell lines studied and rapidly reached an intra/extracellular equilibrium after delta-ALA was added to the culture medium. The increase in intracellular fluorescent porphyrin was dependent on the level of delta-ALA in the medium and the incubation time and was directly related to the phototoxicity observed upon exposure of cultured monolayers to light. The data demonstrate that equivalent levels of phototoxicity can be attained by exposing cells to 0.04 mM delta-ALA for 24 h or to 0.5 mM delta-ALA for 2 h. These findings may have implications for optimization of PDT treatment regimens that use delta-ALA.
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PMID:Time-dependent intracellular accumulation of delta-aminolevulinic acid, induction of porphyrin synthesis and subsequent phototoxicity. 907 22

Aminolevulinic acid (ALA) is being used as a "prodrug" for photodynamic therapy. The side effects of ALA have been only anecdotally reported and these effects as well as pharmacokinetics of the photosensitizing end product of ALA, protoporphyrin IX (PpIX), in patients undergoing operation are unknown. This study systematically determines the side effects of ALA and pharmacokinetics of PpIX in patients undergoing abdominal surgery. Patients were given 30 or 60 mg/kg ALA preoperatively, kept in subdued light for 48 hr, and monitored clinically and with laboratory tests for 5 to 7 days and for at least 2 months thereafter. Periodic plasma samples and tissue biopsies were analyzed for PpIX concentrations using a photodiode array system. No patient developed symptoms of porphyria other than nausea and vomiting, which occurred in 20%. Nearly one-quarter of patients developed transient abnormal liver functions. No patient developed cutaneous phototoxicity, abnormal neurologic function, or unexpected postoperative laboratory tests. The times of peak plasma, skin, skeletal muscle, omental, mucosal, muscularis mucosal, and tumor concentrations of PpIX varied among patients. In general, PpIX concentrations were significantly greater with the higher dose of ALA. Tumor PpIX concentrations were significantly greater than in other tissues except liver. In conclusion, ALA, up to 60 mg/kg, is associated with minimal side effects in patients undergoing operation. Actual tissue concentrations of PpIX suggest that endogenous photosensitization using systemically administered ALA is a mode of PDT feasible for treatment of adenocarcinomas of the gastrointestinal tract in humans.
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PMID:Side effects and photosensitization of human tissues after aminolevulinic acid. 912 92

Photodynamic therapy (PDT) is an experimental, noninvasive treatment of different malignant tumors. The principle is that applied photosensitizing substance selectively accumulate in neoplastic cells. Exposure to visible light then leads to the destruction of the tumor tissue. Following intravenous or oral administration of the photosensitizer (PS) generalised skin photosensitivity is the major side effect. Topical application of the PS under occlusive foil a novel method. Topical PDT (TPDT) is most investigated with 5-Aminolevulinic acid (ALA) as PS. ALA is a precursor of endogenous porphyrins in the biosynthetic pathway for heme. This new modality is increasingly and successfully used to treat precancerous and cancerous epithelial skin tumors, like actinic keratoses, basal-cell carcinoma, squamous-cell carcinoma and Bowen disease. An other approach of ALA-TPDT are nontumoral applications, especially psoriasis. ALA-TPDT is well tolerated by patients and makes excellent cosmetic results. It is an alternative treatment for various superficial skin tumors.
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PMID:[Topical photodynamic therapy in dermatology]. 975 21

Photodynamic therapy (PDT), due to its tumor selectivity, represents an alternative approach to diagnose and treat cervical intra-epithelial neoplasia (CIN) without altering normal surrounding tissue. Our aim was to investigate the pharmacokinetics and the selectivity of 5-aminolevulinic acid (5-ALA)-induced porphyrin fluorescence after topical administration, to obtain basic clinical data for future diagnostic fluorescence imaging and PDT protocols for CIN. Twenty-eight non-pregnant women with a cytological diagnosis of low-grade or high-grade squamous intra-epithelial lesions were included. An aqueous solution containing 3% 5-ALA was topically applied 1 to 6 hrs prior to conization using a cervical cap. After excision, porphyrin-induced fluorescence was quantified in dysplastic (n = 14) and normal epithelium (n = 28) by means of quantitative fluorescence microscopy. High values of porphyrin fluorescence were found in squamous epithelium between 150 and 450 min, with a maximum at 300 min following administration of 5-ALA. Ratios of porphyrin fluorescence of dysplastic vs. surrounding normal epithelium were 1.3 and 1.21 for CIN 1 (n = 3) and CIN 2 (n = 3), respectively. In CIN 3 patients (n = 8), this ratio was 2.35; the best selectivity of 5-ALA-induced porphyrin fluorescence in CIN 3 lesions (ratio 3) was observed with a topical administration time of between 150 and 250 min. Our results demonstrate that patients with CIN 3 show higher 5-ALA-induced fluorescence compared with normal epithelium. The optimal administration time of topically applied 5-ALA was between 3 and 4 hr. Our data suggest that topical ALA-PDT and photodynamic diagnosis might be suitable for detecting CIN.
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PMID:Pharmacokinetics and selectivity of aminolevulinic acid-induced porphyrin synthesis in patients with cervical intra-epithelial neoplasia. 976 64


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