Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Chlorophyllides”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 595 records · Page 33Linked to original sources
PubMed2004

[Polylactic acid nanoparticles across the brain-blood barrier observed with analytical electron microscopy].

The blood-brain barrier (BBB) is a huge obstacle in therapy of brain diseases, for it hinders the delivery of water-soluble molecules and those with molecular weight above 500 from the circulation system to the brain. Polysorbate 80 (Tween 80, T-80)-coated polylactid acid(PLA) nanoparticles represent a tool to transport such drugs across the BBB. Transcytosis is put forward as one mechanism of drug-loaded nanoparticles across the blood-brain barrier (BBB). However little is known about it. Electron microscopy is an important method in the investigation on nanoparticles injected into the experimental mice. In this study it was found by fluorescence microscope that fluorescence existed along the capillary dissepiment. Some nanoparticles distributed in the brain capillary endothelial cells and brain tissue outside the microvaculum, which was observed by transmission electron microscopy. These particles were proved to be the Copper chlorophyll loaded nanoparticles which containing Cu detected by AEM. The in vivo experiments demonstrated directly that the PLA nanoparticles can pass the BBB indeed and transcytosis by microvascular endothelial cells may be the mechanism. The results provided an efficient way of drug-delivery targeting the brain. Copper chlorophyll could be used as a new symbol of nanoparticles in in vivo experiment.

Animals↗
PubMed2005

Hydrophilic gels containing chlorophyllin-loaded liposomes: development and stability evaluation.

The aim of this study was to develop and characterize hydrophilic gels containing chlorophyllin(CHL)-loaded liposomes as well as to evaluate their stability. Two different CHL-loaded liposome dispersions using non-hydrogenated and hydrogenated soybean lecithin were prepared, characterized for their particle size, polydispersity index and trapping efficiency and incorporated in Carbopol 940 NF hydrogel. The gels obtained were analyzed for flow properties, pH values and CHL content. The control liposome-free gel was obtained by incorporating the CHL solution in the hydrogel. The stability of the gels was evaluated in terms of rheological properties, pH values and CHL content during 6 months' storage at 20 +/- 2 degrees C. Suitable gel formulations for topical use were obtained revealing shear-thinning plastic flow behaviour without significant thixotropy during the whole period of examination. High yield values of the samples during the whole period indicated a long-term stability of the gel formulations. The gel formulations expressed a mild acid value acceptable for topical preparations. After 6 months' storage the CHL content was highest in the gel containing non-hydrogenated lecithin liposomes, followed by the gel containing hydrogenated lecithin liposomes and liposome-free gel, indicating that the encapsulation of CHL in liposomes led to a greater stability of CHL.

Acrylic Resins↗
PubMed2005

The chlorophyllin-induced cell cycle arrest and apoptosis in human breast cancer MCF-7 cells is associated with ERK deactivation and Cyclin D1 depletion.

Targeting the mitogen-activated protein kinases (MAPKs) has been suggested as a novel strategy to treat cancer. Chlorophyllin (CHL) is the sodium-copper salt of chlorophyll derivative and is a commonly used food dye for green coloration; CHL was found previously to retard growth of the human breast carcinoma MCF-7 cells. Extracellular signal-regulated kinases (ERKs) constitute a subfamily of MAPKs, participating in cell survival, proliferation and differentiation. We report here the first evidence that CHL deactivates ERKs to inhibit the breast cancer cell proliferation. The results from flow cytometry showed that 200 microg/ml CHL reduced the phosphorylated and activated ERK-positive cells in different cell cycle phases from the control of >96 to <38% at 24 h of incubation; the ERK deactivations occurred in both dose- and time-dependent manner, so that nearly all ERKs were de-activated by 400 microg/ml CHL at 72 h of treatment. Immunoblot studies, however, illustrated that the levels of total ERKs were not significantly affected by the CHL treatments, suggesting that the phytochemical retards the enzyme activation rather than its expression. Cyclin D1, but not its enzyme Cdk6, was also depleted after the CHL treatments; the depletions were associated with elevations of G0/G1 cells. Apoptosis occurred time-dependently with the ERK deactivations by 400 microg/ml CHL; the apoptotic cells elevated from 2.7-fold of the control level at 24 h, to 4.7-fold at 48 h and to 16.6-fold at 72 h of treatment. Bcl-2 was also depleted at 72 h when there was the most prominent elevation of the apoptotic cells, suggesting that it participates during the exacerbation rather than the initiation phases of the CHL-induced apoptosis. Results from this study support further research on CHL for preventing and treating those tumors with deregulated ERK activations.

Apoptosis↗
PubMedDate not supplied

Chlorophyllin, an antimutagen, acts as a tumor promoter in the rat-dimethylhydrazine colon carcinogenesis model.

Chlorophyllin (CHL), the water soluble sodium/copper salt of chlorophyll, was investigated for its effect on colorectal cancer risk in the rat-dimethyldrazine colon carcinogenesis model. Ninety weanling Fisher 344 male rats were treated with five weekly injections of 1,2 dimethylhydrazine (DMH), 20 mg base/kg body weight. Rats had been previously divided into three groups, consuming either rat chow and water (Group I), rat chow and CHL 1.5 mM in water throughout the experiment (Group II), or water and rat chow during DMH injection, adding CHL 1.5 mM to the drinking water after completion of the DMH treatments. At sarcifice, the incidence and yield of colorectal tumors were as follows: Group I 10% and 0.1; Group II, 23% and 0.27; and Group III, 47% and 0.53 (p less than 0.005 for incidence and = 0.003 for yield). These data demonstrate that, though it is well established that CHL is an antimutagen, CHL in this colorectal carcinogenesis model acted as a tumor promoter.

1,2-Dimethylhydrazine↗
PubMedDate not supplied

[Russian photosensitizer radachlorine in photodynamic therapy for epibulbar and choroid tumors: experimental studies].

The authors used the Russian agent Radachlorine as a photosensitizer (PS) in photodynamic therapy (PDT) for epibulbar and chorioid tumors. Analyzing the results suggests that the efficacy of Radachlorine used as PS in a correctly adjusted dose in PDT may be high. The optimization of effects in the experiment was observed when Radachlorine was used in a dose of 3 mg/kg with a light radiation dose of 500 mW/cm2 upon 5-min exposure. However, a rapid relapse in some cases indicates the instability of the effect and makes it necessary to make repeated PS injections and PDT sessions.

Animals↗
PubMedDate not supplied

[Experimental (in vivo) study of the capacities of use of radachlorine (chlorine E-6) for photodynamic therapy in ophthalmology].

To study the capacities of ophthalmological application of the photosensitizer Radachlorine (0.35% solution for intravenous injection), the authors carried out a series of in vivo experiments on rabbits. They studied the time parameters of distribution of the agent in the chorioretinal complex and the reaction of newly formed vessels to photodynamic therapy. Radiation of a diode laser at a wavelength of 0.662 microm was used to stimulate the photosensitizer. A video micro-camera adapted to the ocular of a split lamp was applied to fluorescence fixation. Superficial corneal vascularization was used as a model of the neovascular membrane in response to the application of a non-penetrating silk suture. The findings suggest that photodynamic therapy using Radachlorine is safe and effective in treating ocular tissue neovascularization.

Animals↗
PubMed2005

The susceptibility of anaerobic bacteria isolated from periodontal diseases to photodynamic inactivation with Fotolon (chlorin e6).

Photodynamic inactivation (PDI) may be a very promising alternative method for the antimicrobial treatment of periodontitis. Several studies have demonstrated the sensitivity of subgingival flora to PDI using toluidine blue, methylene blue, and chlorin e6 derivatives. In the present study we report the activity of the Fotolon sensitizer, composed of chlorin e6 and polyvinylpyrrolidone (PVP), against anaerobic bacteria isolated from periodontal diseases. Over 99.9% reduction in colony forming units in 20 Gram-positive and 30 Gram-negative clinical anaerobic strains was obtained.

Bacteria, Anaerobic↗
PubMedDate not supplied

[Photodamage of gram-positive and gram-negative bacterial cells in the presence of chlorin e6 derivatives].

The kinetics of photoinduced damage sensitized by chlorine e6 and its derivatives was studied in Escherichia coli and Bacillus subtilis. The effectiveness of E. coli photoinactivation in the presence of chlorines was 100-200 times lower as compared with that of B. subtilis. The structural organisation of bacterial cell walls apparently played an essential role in the penetration of tetrapyrrole pigments into the cell and in their binding.

Bacillus subtilis↗
PubMedDate not supplied

[The chlorine e6-photosensitized inhibition of human thrombocyte aggregation].

ADP-induced aggregation of platelets in the presence of chlorin E6 under the action of visible light depending on the pigment concentration and the time of light action was studied. It was shown that the photosensitized effect of chlorin E6 on the platelet-enriched plasma results in platelet aggregation inhibition.

Adenosine Diphosphate↗
PubMed1991

Mechanism of photosensitization by microsphere-bound chlorin e6 in human bladder carcinoma cells.

Photodynamic therapy is an experimental method of cancer treatment in which a photosensitizer is administered and subsequently the tumor is irradiated with light. Due to problems of prolonged skin phototoxicity with hematoporphyrin derivative, new photosensitizers and methods of localization are being sought. The goal of this study was to compare the photosensitizer chlorin e6 (Ce6) free and bound to 1-micron-diameter microspheres (MS) for phototoxicity, uptake and efflux characteristics, phagocytosis rates in malignant and benign cells, and effects of NaN3, D2O, and buthionine sulfoximine on phototoxic efficacy. Incubation of MGH-U1 human bladder carcinoma cells with Ce6-MS (0.43 microM Ce6-equivalent; 18 h) and subsequent irradiation using an argon laser-pumped dye laser at a radiant exposure of 20 J/cm2 caused 100% cell death 24 h after irradiation. In contrast, MGH-U1 cells incubated with free Ce6 (0.43 microM; 18 h) remained 100% viable 24 h after irradiation at a radiant exposure of up to 50 J/cm2. The presence of D2O during irradiation increased the phototoxicity to MGH-U1 cells, whereas the presence of NaN3 decreased it; these data support an important role for 1O2. Irradiation of MGH-U1 cells in the presence of the glutathione depleter buthionine sulfoximine also increased the phototoxicity, demonstrating a role for intracellular glutathione and possibly free radical intermediates. The cellular uptake of Ce6 was approximately 50 times lower than that of Ce6-MS at equivalent incubation concentrations. Efflux experiments showed that the phototoxicity of Ce6-MS was reduced by 40% for a 5-h washout time as compared to no washout time. In contrast, for free Ce6, the decrease was 95.3% under identical conditions. Because the total intracellular concentration of Ce6-MS after an efflux time of 5 h was only slightly changed, the decreased phototoxicity is attributed to an altered intracellular localization. Confocal laser scanning fluorescence microscopy data appear consistent with this hypothesis although they are not conclusive. The observed patterns were different at 0 and 5 h. Comparison of the phagocytosis rates of Ce6-MS by carcinoma and benign cells showed that on average 20 MS/cell were phagocytosed by MGH-U1 compared with 2.5 and 8.3 in the benign human fibroblasts and keratinocytes, respectively. After incubation with Ce6-MS (0.1 microM; 18 h) and irradiation at 10 J/cm2 the surviving fraction of MGH-U1 cells was 76.3 +/- 0.95% (mean +/- SE) and 40 +/- 3.49% for fibroblasts. In contrast, for keratinocytes the surviving fraction was 93.5 +/- 0.83%.(ABSTRACT TRUNCATED AT 400 WORDS)

Buthionine Sulfoximine↗
PubMed1991

[Chlorine e6-sensitized photoinhibition of thrombocyte aggregation. Participation of active oxygen forms].

It has been shown that photosensitized action of chlorin e6 (Che6) on platelet-rich plasma leads to platelet aggregation inhibition. Che6-sensitized photoinactivation of platelets was intensified in the presence of singlet oxygen interceptor. The aggregation rate of light-irradiated platelets in the presence of Che6 in D2O buffer was higher than in H2O buffer. The participation of active oxygen forms in the determination of platelet function has been considered.

Chlorophyllides↗
PubMed1991

Neuroblastoma grafts are noninvasively removed within mouse neocortex by selective laser activation of intracellular photolytic chromophore.

Studies of neural cell transplantation would be aided by the ability to damage or destroy, noninvasively and extremely selectively, grafted cells at defined times following their initial implantation. Mechanisms of graft integration and performance could be investigated, also providing insight into natural injury and repair mechanisms. At long wavelengths between 650 and 850 nm, laser energy can penetrate several millimeters of brain tissue without absorption or damage to the unpigmented tissue. However, targeted cells are selectively damaged by illumination at these long wavelengths if they contain latex nanospheres with incorporated cytolytic chromophores (e.g., chlorin e6). Light penetration allows many thousands of cells to be lesioned simultaneously, noninvasively, and deep within a surrounding matrix of other tissue. Such laser-activated damage has been termed laser photolysis (PL). We studied damage to C1300 neuroblastoma (NB) cells grafted into mouse neocortex in vivo by this process of PL. NB cells provided a simple and reproducible model of neural grafting, allowing direct histologic assessment of cellular growth and viability by distinct morphologic and mitotic criteria. Cells were cultured by standard methods, labeled in vitro by brief exposure to nanospheres containing chlorin e6, and grafted to sites within deep layers of mouse neocortex. Mice were exposed to transcranial, fractionated, unfocused pulses of 670-nm-wavelength energy totaling 90-120 J/cm2. We histologically assessed graft growth and cellular viability over a period from 2 d to 4 weeks, measured graft volumes quantitatively during the period of early rapid growth in controls (2 and 7 d), and generated 3-D reconstructions from serial sections to assist in visual analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Synthesis of zinc chlorophyllin a and its preliminary clinical application].

A method for synthesis of zinc chlorophyllin a (I), a promising drug for clinical application, is presented. Taking silkworm faeces as a raw material. Chlorophyll was extracted with ethyl alcohol. After concentration the solid formed was dissolved in petroleum ether and the solution was subjected to column chromatography to separate pheophytin a and chlorophyll a. The products were dissolved in ethyl ether and the Mg in the products was stripped off with concentrated hydrochloric acid. The excess hydrochloric acid in the solution was neutralized with ammonia solution and the mixture was hydrolyzed with diluted hydrochloric acid to obtain pheophorbide a, then (I) was synthesized with pheophorbide a and zinc salt. The characteristics of (I) and pheophorbide a were checked by IR, UV and elemental analyses. All results of pheophorbide a coincided with those values reported in literature. The acute toxicity of (I) was tested in mice and the LD50 of (I) was 324 +/- 40 mg/kg. (I) has been applied in several hospitals for several months. It has been found that (I) has outstanding effects on burns and oral sepsis and that it increases the growth of granulation tissue and epithelium remarkably.

Animals↗
PubMed1989

[The distribution of chlorine e6 and its derivatives in HeLa cells studied using luminescence microscopy].

The influence of the chemical structure of porphyrin pigments on their accumulation and localization in HeLa cells has been examined by the scanning fluorescence microphotometry. It has been found that the replacement of carboxyl groups of chlorine e6 for methyl and amino groups has no influence on the pigment distributions in cells. All the pigments are bound by cell membrane structures. The chemical modification of chlorine e6 structure is essential for the ability of pigment to be accumulated by cells that can be used to increase the efficiency of cancer phototherapy. The charge and hydrophobic properties of pigment molecules are of great importance for accumulating porphyrin sensitizers by cells.

Chlorophyllides↗
PubMedDate not supplied

Inhibition of 1,2-dimethylhydrazine-induced nuclear damage in rat colonic epithelium by chlorophyllin.

Chlorophyllin (CHL) was tested for its effect on 1,2-dimethylhydrazine (DMH)-induced nuclear aberrations in rat colonic epithelium. Rats were given water containing CHL (1.5 mM) and food ad libitum. After 5 wks on this dietary regimen, the rats were given a single intraperitoneal injection of DMH (20 mg DMH base/kg body weight). The rats were sacrificed 18 hours later and their colons were removed. Ten consecutive crypts from the proximal and distal portion of each specimen were scored for nuclear aberrations and the karyorrhectic index (KI) was determined. Rats receiving CHL + DMH had significantly fewer nuclear aberrations (lower KI) in the colonic epithelium than rats given DMH alone. This implies that CHL, a known antimutagen, may have anticarcinogenic properties as well.

1,2-Dimethylhydrazine↗
PubMed1985

Enzymatic properties of the lipoxygenase from pea seeds.

A lipoxygenase preparation was obtained from dried green pea seeds. Disc electrophoresis with enzyme staining indicated the presence of only one main isoenzyme corresponding to the isoenzyme PL I according to Yoon and Klein (J. Agric. Food Chem. 24, 955 (1979)), whereas PL II was absent. The assay for pea lipoxygenase has been optimized by using a final concentration of 0.53 mM potassium linoleate in the presence or absence of 0.2% sodium cholate. Without detergent the rho H optimum was 5.9, in its presence 6.8. The formation of conjugated dienes absorbing at 234 nm accounted for 75% of the oxygen uptake. The difference is mainly due to the aerobic formation of oxodienoic acids absorbing at 285 nm via a lipohydroperoxidase activity concomitant with the dioxygenase reaction. Other lipohydroperoxidase products were formed only to a minor extent under aerobic conditions, whereas in the anaerobic lipohydroperoxidase reaction of pea lipoxygenase in the system 13L8-hydroperoxylinoleic acid/linoleic acid fatty acid dimers containing conjugated double bonds were formed additionally. The pea enzyme showed self-inactivation at 37 degrees C, but in contrast to the lipoxygenase from rabbit reticulocytes the self-inactivation appeared only syncatalytically during the aerobic reaction. The antioxidant 2,6-di-t-butyl-4-hydroxytoluene (BHT, 1 mM) did not protect from self-inactivation. In contrast to the lipoxygenase from soybeans, wheat and rabbit reticulocytes the pea lipoxygenase caused a co-oxidation of Cu-chlorophyllin in the presence of linoleate at 5 degrees C. The co-oxidation was completely inhibited by 1 mM BHT which did not inhibit the dioxygenation of linoleate at this temperature. Unlike the reticulocyte enzyme the pea lipoxygenase failed to attack mitochondrial membranes or to produce inhibition of the respiratory chain. The results lead to the conclusion that a simple classification of lipoxygenases in type I and type II enzymes is not justified. A reaction scheme is proposed to explain both the co-oxidative activity and the aerobic formation of oxodienoic acids by pea lipoxygenase, presuming the dissociation of a linoleic acid radical from the ferrous lipoxygenase as a side reaction of the catalytic cycle.

Animals↗