Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The in vivo biologic activities of the hematoporphyrin derivative (Photofrin) and the enriched, so-called "active fraction" (Photofrin II) were determined by measuring the necrosis produced in implanted tumors in DBA/2Ha mice exposed to various total doses of light (20-100 J/cm2) after ip administration of 10 mg/kg standard doses of either Photofrin or Photofrin II. Total relative percentage increase in fluorescence in tumor tissue, as compared to fluorescence in control tissue, also was measured for both Photofrin and Photofrin II. In response to total light doses (630 nm) of 40-100 J/cm2, mice that received Photofrin had comparable amounts of tumor necrosis to those mice that received Photofrin II. At doses of 40-60 J/cm2, 80% tumor destruction resulted, and at 80-100 J/cm2, tumor destruction was 100%. However, at a total light dose of 20 J/cm2, the tumors that received Photofrin II exhibited 60-80% tumor necrosis, whereas those animals that received Photofrin had only small areas of patchy necrosis associated with signs of vascular thrombosis and hemorrhage into the surrounding perivascular stroma. A 25.2% total increase in maximal tissue fluorescence over that in controls was observed for animals that received Photofrin II, as compared to 13.9% for those animals that received Photofrin. It is concluded that the greater demonstrable efficacy of treatment with Photofrin II, as compared to treatment with Photofrin, is due to enrichment of those nonpolar hydrophobic components of the hematoporphyrin derivative mixture that are thought to be primarily responsible for the in vivo biologic activities.
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PMID:Comparison of fluorescence and photodynamic activities of whole hematoporphyrin derivative and its enriched active components. 293 46

Cells of the line NHIK 3025 were incubated with the tumor-localizing porphyrin preparation DHE (Photofrin II). Exposure of light within the porphyrin absorption spectrum resulted in a change of the fluorescence spectra indicative of a movement of porphyrins from binding sites on proteins to more lipid environments, a degradation of the porphyrins in the cells without any significant formation of new porphyrin species. The photodegradation of the porphyrins resulted in a reduced yield of inactivation of cells per incident photon. Several independent estimations indicate that bleaching may play a role in clinical situations.
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PMID:Effect of bleaching of porphyrin sensitizers during photodynamic therapy. 294 34

Photodynamic therapy (PDT) involves the activation of photosensitizing drugs by light of appropriate wavelength. The photosensitive agent Hematoporphyrin Derivative (HPD) appears to be preferentially retained in malignant tumors; irradiation of HPD-containing tissue by light of appropriate wavelength (625 nm) and dose leads to (tumor) tissue destruction. The aim of this study is to achieve maximum tumor control probability with minimum normal tissue photosensitivity. In previous work from our laboratory it has been demonstrated that PDT has its fundamental effects on the tumor and normal tissue microcirculation. As it is well established that hyperthermia (HT) has its major effects in less well vascularized areas of the tumor, the combined modality of HT and PDT might prove to be advantageous. Moreover, suppression of sublethal damage repair by HT has been observed. To overcome the problem of poor light penetration into tissues and the high rate of recurrences following PDT with external irradiation, the combined effects of interstitial PDT with interstitial hyperthermia in a new line of animal experiments were studied in our laboratory. An experimental murine tumor (Rhabdomyosarcoma, type R-1) was transplanted in WAG/Rij rats and, after reaching an average diameter of 2 cm, the active component of HPD, that is Photofrin II, was injected intravenously in different dose schedules (5 mg/kg, 10 mg/kg). After 24 or 48 hrs the tumors were implanted with four flexible catheters, through which either light or heat could be applied. Light was obtained from an Argon-Dye laser system tuned to a wavelength of 625 nm at a dose rate of 75-100 mW per fiber to a dose level of 900 Joule from four linear light applicators. Heat (44 degrees C/30') was delivered by four 27 MHz radiofrequency antennas. Dose response relationships for PDT alone, HT alone and PDT combined with HT were established with cure as endpoint. This study showed that these two modalities, in the proper sequence and spacing, result in an augmented cytotoxicity on the tumor cells in vivo. With the combined modality treatment a cure rate of 41% (90 days) was obtained. As the implantation of flexible catheters is a well-known technique in radiation therapy practice, the potentiating effects of interstitial HT combined with interstitial PDT in solid tumors is very promising and clinical studies are warranted.
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PMID:Interaction of interstitial photodynamic therapy and interstitial hyperthermia in a rat rhabdomyosarcoma--a pilot study. 296 16

While photodynamic therapy (PDT) for cutaneous malignancies including dermal recurrences of breast cancer and basal cell carcinomas has shown great promise, PDT of malignant melanoma has remained incompletely understood. A comparison study of the effects of PDT on human xenograft amelanotic and melanotic malignant melanoma in the athymic nude mouse model was performed. Twenty-four hours after ip administration of Photofrin II, the responses to total laser light doses of 25-300 J/cm2 were evaluated by histologic examination. Animals were also sacrificed 24 hours after administration of Photofrin II without light, and their uptake and localization of hematoporphyrin derivative (HpD) for each tumor were measured and compared. The results indicate that human xenograft melanotic melanoma, despite the fact that it contains more HpD than does amelanotic melanoma, is far less responsive to PDT. This result appears to be due to the competing chromophore melanin, which may inhibit the photochemical reaction at several key points.
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PMID:Photodynamic therapy of human malignant melanoma xenografts in athymic nude mice. 296 36

Photodynamic therapy (PDT) is being utilized in the treatment of a wide variety of malignant tumors. Results using PDT have been encouraging, and controlled clinical trials are currently being performed. The procedure exploits both the tumor-localizing and -photosensitizing properties of hematoporphyrin derivative or its purified component, Photofrin II. When this porphyrin mixture is administered systemically, it is retained preferentially in tumor tissue as compared to surrounding normal tissue. Localized tumor destruction induced by PDT results from the photochemical generation of cytotoxic oxygen species within the tumor. This review will provide a summary of historical and current research pertaining to molecular, cellular, and tissue responses induced by PDT. Emphasis is placed on information related to the chemistry of current photosensitizers, subcellular targets, preclinical treatment parameters, and clinical responses following PDT.
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PMID:Molecular, cellular, and tissue responses following photodynamic therapy. 297 43

The response to Photofrin II-induced photosensitization on the activities of mitochondrial monoamine oxidase (MAO) and adenylate kinase (AK) were studied in order to gain further insight into site specific effects. Utilizing intact mitochondria in vitro, both MAO, located on the cytoplasmic side of the outer mitochondrial membrane, and AK, located in the intermembrane space, were inhibited by exposure to Photofrin II plus light; inhibition was drug-dose and light-dose dependent. However, MAO activity was inhibited to a greater extent than AK; at 35 micrograms/ml of Photofrin II and 160 J/cm2, MAO activity was decreased by 80% whereas AK activity was inhibited by 30%. Higher doses of Photofrin II had no further effect on AK activity. Studies of photosensitization of AK in different mitochondrial preparations demonstrated that inhibition of activity was evident only when mitochondrial membranes containing sequestered porphyrins were present in the reaction mixture. Using an in vivo-in vitro protocol and sampling at 2 to 72 h after administration of 25 mg/kg of Photofrin II, photosensitization of MAO (30% inhibition) was seen at 2 h after drug treatment but inhibition of activity was not observed at later times. AK activity was unchanged over the entire time course. Compared to cytochrome c oxidase, located in the inner mitochondrial membrane and which displayed a sustained inhibition of activity, we suggest that inhibition of MAO or AK activities probably does not contribute to the tumor cytotoxicity under the usual conditions used for photodynamic therapy.
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PMID:Photosensitizing effects of Photofrin II on the site-selected mitochondrial enzymes adenylate kinase and monoamine oxidase. 303 10

Photodynamic therapy (PDT) was performed utilizing a cylindrical optical fiber to determine feasibility of distal ureteral treatment on 10 study and two control NIH foxhounds. The study animals were administered three mg./kg. dihematoporphyrin ether (Photofrin II) intravenously followed 48 hours later by open cystotomy. One ureter was irradiated with 42 joules of 630 nm. light delivered by a 660 micron diameter optical fiber modified for cylindrical light distribution. Intravenous urography was performed both at three days and six weeks post PDT. Hydroureteronephrosis was revealed in one treated ureter and one untreated ureter. Mild dilatation of the ureter was noted by urography in another treated ureter and in one ureter that did not undergo light irradiation; no distal obstruction was revealed in either case by proximal infusion of saline or by histopathology. Nine of the 10 treated ureters were found to have either no abnormal pathology or only minimal lymphocytic infiltration. In this study, the normal ureter was shown to tolerate photodynamic therapy at energy densities equivalent to those used to effect tumor regression and the feasibility of using a cylindrical optical fiber for treatment of ureteral malignancies was confirmed.
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PMID:Response of normal canine ureter to photodynamic therapy using a cylindrical fiber. 333 96

This paper deals with the interaction of interstitial hyperthermia (HT) and interstitial photodynamic therapy (PDT). Its main focus, however, is on a newly developed heating system; phantom studies as well as temperature-response data obtained from the in vivo experiments are presented. Heat was delivered by thin, flexible wire antennas operating at a frequency of 27 MHz. Measurements in muscle-equivalent phantom with infrared thermography were performed. Uniform heating over the inserted length of the antenna was obtained and impedance matching appears possible by simple variable air coils, thereby minimizing the reflected power to less than 20%. Light was obtained from an Argon-Dye laser system tuned to a wavelength of 625 nm at a dose rate of 75-100 mW per fiber to a total incident dose of 900 J from four linear light applicators. An experimental murine tumor (Rhabdomyosarcoma, type R-1) was transplanted in WAG/Rij rats and, after reaching an average diameter of 2 cm, the active component of haematoporphyrin derivative (HPD), Photofrin II, was injected intravenously. The tumors were subsequently implanted with four flexible catheters, through which either light or heat could be applied. Dose-response relationships for PDT alone, HT alone and PDT followed by HT were established with cure as endpoint. The animal experiments showed that with the use of low-frequency wires a good localized heat distribution in the tumors can be obtained. Moreover, this study showed that PDT and HT, in the proper sequence and only when optimal temperatures are reached, result in an augmented cytotoxicity on the tumor cells in vivo; i.e. a cure rate of 41% was obtained.
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PMID:Interstitial hyperthermia using 27 MHz wire antennas and interstitial photodynamic therapy in a rat rhabdomyosarcoma: phantom and animal studies. 335 20

HpD photodynamic therapy (PDT) was performed on 4 patients with superficial esophageal cancer, 20 patients with 22 early gastric cancer lesions and one patient with advanced gastric cancer. About 50 h before irradiation, 3 mg/kg of HpD or 1.3-2.5 mg/kg of Photofrin II was injected intravenously. The entire lesion including a 5-mm border of normal surrounding mucosa, was irradiated with an argon dye laser at 630nm wavelength with an output of 100-400mW at the tip of the fiber. Complete response (CR) to HpD-PDT was obtained in 2 of 2 mucosal esophageal cancers, and one of 2 submucosal lesions, totalling 3 of 4, and in 13 of 13 mucosal gastric cancers and 7 of 9 submucosal lesions totalling 20 of 22. The depths of cancer involvement were determined endoscopically. In Borrmann 1 lesion with muscularis externa involvement, in spite of two trials with HpD-PDT, only partial response (PR) was obtained. Tumor laser dose had to be more than 90 J/cm2, and in several cases combined hot biopsy with electrodiathermy and/or repeated HpD-PDT was needed to obtain CR. HpD-PDT is indicated for superficial esophageal cancer and depressed and/or assembled protuberant-type of early gastric cancer with poor risk.
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PMID:[Indications for and limitations of HpD photodynamic therapy for esophageal cancer and gastric cancer]. 338 14

Nine dyes, all potential sensitizers for photodynamic cancer therapy (PDT), were injected in mice with C3H mammary carcinomas. Twenty-four hours later the animals were sacrificed and the dye concentrations in tumors and 9 other tissues were measured by means of spectrofluorimetry. The 9 dyes were: Photofrin II (PII), hematoporphyrin (HP)-di-hexyl-ether, PSD-007 (a sensitizer used in clinical trials in China), tetraphenyl porphine tetrasulfonate (TPPS4), tetra(3-hydroxy phenyl)porphyrin (3THPP), aluminium phthalocyanine tetrasulfonate (AlPCTS), aluminium phthalocyanine (AlPC), chlorin e6 (Chl e6) and merocyanine 540 (MC 540). The porphyrin precursor delta-aminolevulinic acid was also tested and found to induce porphyrin fluorescence in tumors and some other tissues. The best tumorlocalizer of those tested was 3THPP. This drug also showed a favorable tissue distribution. The following dyes showed lower skin/tumor concentration ratios than PII (the most widely used dye for PDT): Chl e6, PSD-007, HP-di-hexyl-ether and 3THPP. Low brain/tumor ratios were found for: PSD-007, HP-di-hexyl-ether, 3THPP, TPPS4 and AlPCTS.
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PMID:A comparison of different photosensitizing dyes with respect to uptake C3H-tumors and tissues of mice. 358 Oct 53


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