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PubMedDate not supplied

The effect of photodynamic therapy with rose bengal on posterior capsule opacification in rabbit eyes.

We investigated the in vivo effect of photodynamic therapy (PDT) using rose bengal on the development of posterior capsule opacification (PCO). Endocapsular phacoemulsification was performed on white rabbits, which were divided into 4 groups: control group; group 1, treated with visible light only; group 2, treated with rose bengal only, and group 3, treated with PDT. In the case of the PDT group, rose bengal dissolved in sodium hyaluronate was injected into the empty capsular bag and treated with visible light. Three months after surgery, the rabbits were sacrificed and the eyeballs enucleated. The obstruction rate of visible light caused by PCO was measured with an optical powermeter. The mean obstruction rate was 30.6% in the control group, 28.3% in group 1, 19.3% in group 2, and 14.3% in group 3. Group 3 showed a statistically significant decrease in PCO compared with the control group and group 1 (p = 0.0014). Our results suggest that PDT using rose bengal effectively decreased PCO in rabbit eyes.

Animals↗

PubMed2005

Rose Bengal located within liposome do not affect the activity of inside-out oriented Na,K-ATPase.

DPPC:DPPE-proteoliposomes (in which the enzyme is inside-out oriented) and DLOPC:DLOPE-proteoliposomes (in which the enzyme is only 40% inside-out oriented) is an excellent model for studying the selective effect of the reactive oxygen species, produced by the photo-activation of Rose Bengal. Both proteoliposomes used, when submitted to photo-irradiation with laser using 1200 mJ/cm2 energy dose, in the absence of the Rose Bengal, did not shown any effect in the ATPase activity and in the integrity of its systems. Also, no effect was observed using 50 microM of Rose Bengal encapsulated in the interior of the DPPC:DPPE-proteoliposome system. But, when we use 50 microM of Rose Bengal, present only in the extravesicular environment, and photo-irradiation with a laser dose of 200 mJ/cm2, it results in the loss of 40-50% of the ATPase activity, with damage of the DPPC:DPPE-proteoliposome integrity. Using a dose of 400 mJ/cm2 the ATPase activity was totality lost. Consequently, these effects could be correlated with direct damage in the peptide structure. The photo-irradiation of the system constituted by DLOPC:DLOPE-proteoliposome in the presence of Rose Bengal, encapsulated only in the interior compartment or in the extra-liposomal environments, revealed a gradual decrease of the ATPase activity, maintaining it at 30% after a dose of 1200 mJ/cm2 and losing total ATPase activity at 800 mJ/cm2, respectively, with the loss of integrity of this vesicular system in both conditions studied. The generated singlet oxygen could attack the double linkage present in the fatty acid structure of the lipid instead of the amino acid in the protein structure and, in a second step, result in an indirect inactivation of the enzyme activity. In summary, these results indicated that singlet oxygen species produced by photo-oxidation of Rose Bengal using laser light could act in protein and lipid structure depending on its proportion or distribution.

Liposomes↗

PubMed1978

Rapid radioiodination of rose bengal at room temperature.

Published methods for radioiodination of rose bengal require reaction times of 1 hr or more at temperature from 50 to 120 degrees C. Through the use of an acidified ethanol solvent and potassium iodate oxidant, purified rose bengal is radioiodinated at room temperature within 15 min with chemical yields ranging between 93 and 97%. Radiochemical impurities are sufficiently minimized to permit preparation in a single 10-ml serum vial, requiring no additional purification steps. The method reported here is readily adaptable to cold-kit preparation.

Iodine Radioisotopes↗

PubMed1998

Rose bengal dye concentration and volume delivered via dye-impregnated paper strips.

PURPOSE: The technique of administration and the resulting volume and concentration of the dye delivered to the eye via dye-impregnated paper strips are not standardized or known. The purpose of this study was to use a standard technique for preparation of rose bengal dye from commercially available paper strips to determine the variability in concentration based upon soak time, and to determine the volume delivered by such a technique to a model eye. METHODS: Rose bengal filter paper strips were wetted for either 15, 30, or 45 s, and the resulting concentration of dye eluted was determined by spectrophotometry. With the same preparation technique and a 15-s soak time, the strip was applied to wetted filter paper, as a model for the moist surface of the eye. The volume of solution delivered was calculated by weight. RESULTS: Concentrations of rose bengal for the various soak times were: 15 s: 7.64 (+/- 1.11) by 10(-6) g/ml; 30 s: 9.70 (+/- 1.79) by 10(-6) g/ml; and 45 s: 10.27 (+/- 0.66) by 10(-6) g/ml. The volume delivered to the eye model with this technique was 17.43 microliters (+/- 3.09). CONCLUSIONS: The concentration of rose bengal dye delivered to the ocular surface by means of a wetted strip is relatively low and soak time/technique-dependent. This suggests a possibility that results in clinical studies with rose bengal strip application may be different than if controlled volume applications of commercially available 1% liquid rose bengal dye are used.

Cornea↗

PubMed1996

In vitro study for staining and toxicity of rose bengal on cultured bovine corneal endothelial cells.

It has recently been reported that rose bengal (RB) is actually not a vital dye and that it has an intrinsic toxic effect. Therefore, we conducted a study to determine its staining capability and the presence of intrinsic toxicity. We also examined its effects on the proliferation of cultured bovine corneal endothelial cells. The cells stained despite short exposure (1 s) to rose bengal under a fluorescein photomicroscope. The cell nucleus stained first, followed by the cytoplasm; the intensity was directly dependent on the exposure time. Although the entire cell layer did not stain at an RB concentration of 0.001%, the cell layer stained diffusely above a concentration of 0.01%. At a 5% concentration, areas of cellular detachment and lysis were noted. The degree of cellular change was directly proportional to the concentration of RB and the exposure time. Cellular damage included cell swelling, intracytoplasmic vacuole formation, cell detachment, and lysis. The presence of light augmented the toxic effect of RB on cultured endothelial cells and was statistically more significant than RB's intrinsic toxic effect. Exposure to RB concentrations > 0.01% induced statistically significant concentration-dependent inhibition of cell proliferation. These results suggest that rose bengal may not actually be a vital dye on cultured bovine corneal endothelial cells and that it has intrinsic inhibitory and toxic effects with additional phototoxic effects on corneal endothelial cells. Furthermore, cell proliferation was markedly inhibited after exposure to RB.

Animals↗

PubMed1980

[Use of acidic rose bengal antigen in the plate agglutination test for brucellosis in humans].

The results obtained in the study of the activity of an antigen stained with rose bengale in the plate agglutination test are presented. The analysis of 1309 serum samples from healthy persons and brucellosis patients has shown the high specificity and diagnostic sensitivity of the rose bengale test. The evaluation of the positive result of the rose bengale test should be differentiated in accordance with the degree of agglutination observed in the test. The correlation between the degree of agglutination with the rose bengale antigen and the titer value in Wright's test has been established. The new accelerated test is recommended for large-scale approbation in clinical conditions, epidemiological practice and in the examination of donors at blood donor centers.

Agglutination Tests↗

PubMedDate not supplied

Rose bengal clearance during hepatic regeneration in rats.

Intravenous I131 Rose bengal clearance was conducted in partially hepatectomized rats with a dose of 1 muCi/100 gm body weight. Blood samples were taken at regular intervals up to 25 minutes which were suitable diluted to count the remaining radioactivity. From these values t1/2 and the clearance constants were worked out upto a period of 120 hr after partial hepatectomy. An analysis of the results show that there is a linear correlation between the rose bengal clearance and the regenerating hepatic mass which may be used for quantitative assessment of functional hepatic mass.

Animals↗

PubMed1970

Effects of rose bengal on bile secretion in the rabbit: inhibition of a bile salt-independent fraction.

The authors have studied the influence of rose bengal, and, by comparison, of uranin, on choleresis in the rabbit. Uranin induced an increase in bile flow and a decrease in bile salt concentration in bile. These results are consistent with an osmotic mechanism, as proposed by Sperber (1959). By contrast, rose bengal induced a marked decrease in bile flow and an increase in bile salt concentration. In rose bengal-treated animals (30 mumoles per kilogram body weight intravenously), bile flow was 65% lower and bile salt concentration 95% higher than in control animals studied during the same periods. The relationship between bile flow and bile salt excretion is consistent in the rabbit, with the existence of a bile salt-independent secretion of 60 mg per minute per kilogram body weight, that is, 60% of bile flow. In rose bengal-treated animals, this fraction was only 15 mg per minute per kilogram body weight. It is concluded that rose bengal inhibits the bile salt-independent fraction. Rose bengal, as other phtalein dyes, is excreted by the liver cells. Its effect on the bile salt-independent fraction suggests that this fraction is secreted by the hepatocytes.

Animals↗

PubMedDate not supplied

Probing the active site of trypsin with rose bengal: insights into the photodynamic inactivation of the enzyme.

In this work the active site of trypsin has been probed with the dye rose bengal. The dye binds competitively to the enzyme, and it can be used as a probe of the active site of the enzyme. On the basis of the emission wavelength, the binding site of trypsin is relatively polar and is similar to that of acetone in its polarity. The triplet state of rose bengal is quenched by trypsin. This quenching may be caused by the tryptophan and tyrosine residues that are in the near vicinity of the trypsin active site. This quenching can compete with the formation of singlet oxygen from the excited triplet state of rose bengal. We demonstrate that the singlet oxygen involved in the photoinactivation of trypsin is produced by the free rose bengal in solution and the bound dye is incapable of producing singlet oxygen. This explains the lack of correlation between photoinactivation efficiency and sensitizer binding capability previously reported by Wade and Spikes.

Binding Sites↗

PubMed1987

Pharmacokinetics and biliary excretion of rose bengal in rats with acute and chronic renal failure.

The effects of glycerol-induced acute renal failure (ARF) and surgically induced chronic renal failure (CRF) on the pharmacokinetics and biliary excretion of rose bengal have been examined in the rat. Both the pharmacokinetics and biliary excretion of rose bengal were unaltered in either ARF or CRF. The latter results in CRF contrast with those of Tse et al (1976, Int. J. Nucl. Med. Biol. 3: 134-137) who reported decreased removal of the dye from blood and reduced biliary excretion. In addition, rose bengal behaves differently from bromosulphophthalein and indocyanine green whose hepatic uptake and initial biliary excretion are known to be decreased in ARF. The results suggest that rose bengal may have a hepato-biliary transport route which differs from that of bromosulphophthalein and indocyanine green, and the findings also emphasize the selective nature of altered organic anion uptake by the liver in ARF.

Acute Kidney Injury↗

PubMed1997

Electron transfer quenching of the rose bengal triplet state.

The potential for electron transfer quenching of rose bengal triplet (3RB2-) to compete with energy transfer quenching by oxygen was evaluated. Rate constants for oxidative and reductive quenching were measured in buffered aqueous solution, acetonitrile and in small unilamellar liposomes using laser flash photolysis. Biologically relevant quenchers were used that varied widely in structure, reduction potential and charge. Radical ion yields (phi i) were measured by monitoring the absorption of the rose bengal semireduced (RB.3-) and semioxidized (RB.-) radicals. The results in solution were analyzed as a function of the free energy for electron transfer (delta G) calculated using the Weller equation including electrostatic terms. Exothermic oxidative quenching was about 10-fold faster than exothermic reductive quenching in aqueous solution. The quenching rate constants decreased as delta G approached zero in both aqueous and acetonitrile solution. Exceptions to these generalizations were observed that could be rationalized by specific steric or electrostatic effects or by a change in mechanism. The results suggest that electron transfer reactions with some potential quenchers in cells could compete with formation of singlet oxygen [O2(1 delta g)]. Values of phi i were generally greater for reductive quenching and, for oxidative quenching, greater in acetonitrile than in buffer. Electron transfer quenching of 3RB2- in liposomes, below the phase transition temperature was slower than in solution for both lipid-soluble and water-soluble quenchers indicating that these reactions may not compete with formation of O2(1 delta g) during cell photosensitization.

Acetonitriles↗

PubMed1986

Binding of nucleotides to nucleoside diphosphate kinase monitored by rose Bengal.

The binding of nucleotides to nucleoside-diphosphate kinase from pig heart was studied using the dye rose Bengal as an optical probe. By difference absorption spectroscopy and by equilibrium dialysis it was shown that one dye molecule strongly bound per enzyme subunit. By competition with nucleotides it was shown that two nucleotide-binding sites exist on each subunit of either unphosphorylated or phosphorylated enzyme: one of them binds ATP or ADP tightly, the other one binds rose Bengal tightly and ADP loosely. As detected by different affinities for rose Bengal the enzyme exists in two conformations: a 'relaxed' conformation induced by the binding of ADP, and a 'tense' conformation induced by the binding of ATP or by phosphorylation.

Adenine Nucleotides↗

PubMed1994

Lid imbrication syndrome. Diagnosis with rose bengal staining.

BACKGROUND: Lid imbrication syndrome is an abnormality of lid apposition in which the upper lid overlies the lower lid. Patients often complain of irritation, tearing, and foreign body sensation. The condition may be difficult to diagnose. METHOD: Twenty-one patients with suspected lid imbrication syndrome were compared with 21 age-matched controls. All patients were given 0.5% topical rose bengal. RESULTS: The diagnosis of lid imbrication syndrome was confirmed by the presence of rose bengal staining of the tarsal conjunctiva of the upper lid margin. The amount of rose bengal staining correlated with the severity of lid imbrication. Eighteen of 21 patients had received a diagnosis previously of dry eye syndrome. Four patients had persistent epithelial defects. CONCLUSIONS: Rose bengal staining of the superior lid margin tarsal conjunctiva offers an extremely reliable aid for diagnosing lid imbrication syndrome. The condition commonly presents as a dry eye or persistent epithelial defect. Treatment ranges from viscous tear substitutes to horizontal lid shortening of the upper lid.

Administration, Topical↗

PubMed2005

Rose Bengal test: diagnostic yield and use for the rapid diagnosis of human brucellosis in emergency departments in endemic areas.

The aim of the present study was to analyse the diagnostic yield of the rose Bengal test for the rapid diagnosis of human brucellosis in an emergency department in an area where the disease is endemic. The study included 711 patients diagnosed initially with brucellosis and 270 controls. Brucellosis patients were divided into three groups: group I, individuals with no regular exposure to or history of brucellosis; group II, individuals exposed repeatedly to Brucella infection; and group III, individuals infected with Brucella who had received appropriate treatment during the previous 12 months. Blood cultures were positive for 445 (62.6%) brucellosis patients, while the remaining 266 (37.4%) patients were diagnosed according to clinical and serological criteria. The overall sensitivity of the rose Bengal test was 92.9%. The specificities for groups I, II and III were 94.3%, 91.7% and 76.9%, respectively, with positive likelihood ratios of 16.5, 10.4 and 4.2, respectively. The diagnostic gain after the performance of the rose Bengal test was good or very good in patients with no previous exposure to Brucella or history of brucellosis, but poor in patients who were exposed repeatedly to Brucella or had a history of brucellosis and a low pre-test probability. Use of the rose Bengal test as the sole technique for the diagnosis of brucellosis in endemic areas should be considered very carefully in the context of patients who are exposed repeatedly to Brucella or have a history of brucellosis.

Adolescent↗

PubMed1984

The photodynamic action of rose bengal on Trypanosoma cruzi.

In the presence of light and oxygen, rose bengal causes oxidative damage to Trypanosoma cruzi. The production of lipid hydroperoxides was demonstrated by thin-layer chromatography, and severe ultrastructural alterations compatible with an increased permeability of the cells, which led to gradual osmotic swelling and ultimately to lysis, were observed by electron microscopy. As a result of this treatment, the infectivity of T. cruzi trypomastigotes in mice was abolished. In addition, under anaerobic conditions, rose bengal was found to undergo a one-electron reduction in intact T. cruzi epimastigotes to produce a carbon-centered free radical as demonstrated by electron spin resonance spectroscopy. The formation of this radical was also enhanced by light.

Animals↗

PubMed1980

Simultaneous 99mTc-P-butyl-IDA and 131I-rose bengal scintigraphy in neonatal jaundice.

Eight neonates with jaundice were studied simultaneously with 99mTc-p-butyl-IDA and 131I-rose bengal. Due to physical decay, 99mTc-p-butyl-IDA failed to demonstrate delayed excretion through the patent extrahepatic biliary tract in 3 of 5 patients with concomitant hepatitis; 131I-rose bengal showed small-bowel activity in all 5. Neither agent demonstrated small-bowel activity in 3 neonates with extrahepatic biliary atresia. Based on this clinical trial, 131I-rose bengal remains the radiopharmaceutical of choice for distinguishing between hepatitis and biliary atresia in these patients.

Animals↗

PubMed1997

Microspectrophotometric analysis of accumulation of the fluorones K-fluorescein, rose Bengal and phloxine red in living plant cells.

Spectrophotometric investigations of dye solutions in different media and of living stained cells from the upper epidermis of the scaleleaf of Allium cepa were carried out with the dyes K-fluorescein, rose Bengal and phloxine red to elucidate the mechanism of the accumulation of these dyes in the cytoplasm, the nucleus and the cell sap. Thin layer chromatography and paper electrophoresis indicate that the K-fluorescein used here contains no detectable contaminants. Besides the main component, rose Bengal contains two components in small quantities with Rf values of 0.64 and 0.57, plus three more components in traces. Besides the two main components (Rf values of 0.83 and 0.73), phloxine red also contains five more components in traces. Electrophoretic investigations reveal that in aqueous solution the fluorones rose Bengal and phloxine red from pH 2.0-11 show a migration toward the anode. K-fluorescein from pH 2.9-10.4 shows a migration toward the anode, but at pH 1.9 a migration toward the cathode. By shaking aqueous solutions of K-fluorescein, rose Bengal and phloxine red at different pH values with different organic solvents, the above used stainings show different spectral absorption curves according to the polarity of the solvent. The position of the absorption maxima and the shape of the absorption curves of these three anionic dyes lead to the conclusion that the staining of the living cytoplasm and nucleus is due to ion accumulation by means of the "ion trap mechanism" within the aqueous phase of the cytoplasm (cytosol) and the nucleus. Adsorption of dye particles in the protein phase of the cytoplasm cannot be excluded. There seems to be a fundamental difference in the vital staining of the protoplasm by anionic and cationic dyes, the latter apparently accumulating as neutral dye molecules in the lipid phase of the protoplasm. The concentration of the dyes used in the living cytoplasm (cytosol) is approximately 0.2-0.05%. During natural and artificial displacement of K-fluorescein from the cytoplasm to the vacuole, it appears that accumulation of the dye within the vacuole is performed through an ion trap mechanism in the form of bivalent ions. Along with natural displacement, it is possible that ion accumulation also occurs in metabolic products.

Allium↗

PubMed2006

Enzyme-assisted photosensitization with rose Bengal acetate induces structural and functional alteration of mitochondria in HeLa cells.

Rose Bengal acetate (RB-Ac) can be used as a fluorogenic substrate for photosensitization of cells both in vivo and in vitro: once inside the cells, RB-Ac is converted into photoactive rose Bengal (RB) molecules which redistribute dynamically in the cytoplasm and, upon irradiation by visible green light, can damage organelles such as the endoplasmic reticulum, the Golgi apparatus, and the cytoskeleton. Recently, evidence has been provided that mitochondria may also be affected. The aims of the present study were to describe RB-induced photodamage of mitochondria in single HeLa cells and to define, on a quantitative basis, the effects of photosensitization on their morphofunctional features. HeLa cell cultures were exposed to 10(-5) M RB-Ac for 60 min and then irradiated with a light emitting diode at 530 nm (total light dose, 1.6 J/cm2). After irradiation, the cells were transferred to a drug-free complete medium and allowed to grow for 24-72 h. Using conventional and confocal fluorescence microscopy, transmission electron microscopy, and flow cytometry, we demonstrate that, in photosensitized cells, mitochondria undergo structural and functional alterations which can lead cells to apoptosis. Interestingly, in our system some cells were able to survive 72 h post-treatment and to recover, exhibiting the same mitochondrial structure, distribution and inner membrane potential as those in untreated controls. Taking into account that the photoactive molecules redistribute dynamically inside the cell upon RB-Ac administration, it may be hypothesized that cells can be differently affected by irradiation, depending on the relative amount and organelle location of the photosensitizer.

Flow Cytometry↗