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Effects of ten steroids on acridine orange uptake and beta-N-acetylglucosaminidase levels in rat liver lysosomes.

Ten steroids have been compared for their ability to modify the rate of uptake of acridine orange by rat liver and by rat liver lysosomes in vivo. The short-term effects of the ten steroids on the specific activity of a lysosomal enzyme, beta-N-acetylglucosaminidase, were also compared. Five of the ten steroids were administered as tritium-labelled compounds and the concentration of steroids or metabolites was measured in rat liver and liver lysosomes at 2.5h and 3.75h after administration. Cortisone acetate, etiocholanolone (5-beta-androstan-3-alpha-01-17-one) and testosterone accelerate and increase the uptake of acridine orange by rat liver lysosomes. Deoxycorticosterone, corticosterone, triamcinolone (9-alpha-fluoro-11-beta, 17, 21-trihydroxy-16-alpha-methyl-pregna-1, 4-diene-3, 20-dione), estradiol-17-beta and progesterone appear to inhibit the uptake of acridine orange by rat liver lysosomes at 2.5 hours. Cortisol and dexamethasone (9-alpha-fluoro-11-beta, 17, 21-trihydroxy-16-alpha-methyl-pregna-1, 4-diene-3, 20-dione) had little effect. All steroids with the exception of etiocholanolone and deoxycorticosterone increase with the specific activity of beta-N-acetylglucosaminidase in the lysosomal fraction at 2.5h. None of the effects at 2.5h are due to lowered protein levels. Lysosomal concentrations of radioactivity following the administration of tritiated steroids were greated for the glucocorticoids, corticosterone and cortisol. Estradiol-17-beta, progesterone and testosterone showed much lower concentrations of radioactivity in isolated lysosomes. Most of the lysosomal radioactivity (73-96%) was associated with the soluble fraction of the disrupted lysosomes.

17-Ketosteroids↗

Induction of mucopolysaccharidosis in rats by treatment with immunostimulatory acridine derivatives.

In the accompanying paper, four dibasic acridine derivatives were reported to induce lysosomal storage of sulfated glycosaminoglycans (sGAG), i.e., mucopolysaccharidosis, in cultured fibroblast (Handrock et al. Toxicol. Appl. Pharmacol. 114, 1992). The purpose of the present morphological and biochemical investigation was to examine whether two representatives of the acridine derivatives, namely 3,6-bis[2-(diethylamino)ethoxy]-acridine and the piperidino analogue, induce mucopolysaccharidosis in intact organisms. Rats were orally treated with 60-80 mg/kg up to 22 weeks. Morphological examination of liver, spleen, and blood lymphocytes yielded cytochemical evidence of mucopolysaccharidosis. Biochemically, up to a 48-fold increase of the urinary excretion of sGAG was found. In the liver and spleen of chronically treated rats, the sGAG contents were elevated by factors up to 56 and 23, respectively. Heparan sulfate and dermatan sulfate contributed most to the total increase of sGAG; chondroitin sulfate was stored to a minor degree. For one compound, the tissue concentrations were determined. It was found that the drug was accumulated in the tissues. Due to their fluorescent properties, the drugs could be detected by fluorescence microscopy to be present in high concentrations within the sGAG-storing lysosomes. On the basis of these observations and of the biochemical data it appears justified to assume a ratio of at least one drug molecule per disaccharide unit of the sGAG to be present in the lysosomes. It is proposed that this leads to the formation of sGAG-drug complexes in the lysosomes. Such complexes may be indigestible substrates for the lysosomal enzymes, thus leading to mucopolysaccharidosis. For toxicologic practice, the cytochemical examination of lymphocytes is recommended as a simple measure for early detection and monitoring of this adverse drug effect.

Acridines↗

Mutagenic activity of some 9-aminoalkyl acridine derivatives on S. typhimurium.

The mutagenic potential of 9-(3'-dimethylaminopropylamino)-acridine and of its 1-nitro and 2-nitro derivatives was investigated by using histidine-requiring mutants of Salmonella typhimurium. The 9-(3'-dimethylaminopropylamino)-acridine exhibited a weak mutagenic activity only on one of the S. typhimurium tester strains, TA1537. The 1-nitro derivative induced mutations with high frequency in strains TA1537, TA1538 and TA98, whereas the 2-nitro derivative was substantially more mutagenic than the parent compound but it was much less mutagenic than the 1-nitro derivative. Pre-mutational damages made by the 1-nitro derivative were repaired by the uvrB gene-repair system, whereas those caused by the 2-nitro derivative could not be repaired by this system. Both the 1-nitro and 2-nitro derivatives induced some mutations in the base-pair substitution strain TA100 carrying a plasmid. The frequency of the his+ mutation induced both by 1-nitro and by the 2-nitro derivatives in strain TA101 lacking a nitro reductase was lower. These results emphasize the involvement of the nitro group in the interaction of acridine derivatives with the bacterial genome.

Acridines↗

Frameshift mutagenesis by acridines in wild-type, uvrB and polA strains of Salmonella typhimurium with and without plasmid pKM101.

A large range of acridines, including several anilinoacridines which are active as antitumour agents, have been studied for their ability to revert derivatives of Salmonella typhimurium strains carrying the frameshift marker hisC3076. The strains used all carried deep-rough (rfa) mutations, and were either wild-type with respect to DNA-repair capacity or carried uvrB, polA1 or polA3 (amber) mutations. Derivatives with and without the mutation-enhancing N group plasmid pKM101 were also used. 9-Aminoacridine and other acridines appeared similar to the anilinoacridines for the most part, in that frameshift mutagenesis and toxicity appeared to be unaffected by the uvrB mutation or by the presence of plasmid pKM101. Exceptions were ICR191, 3-NO2-acridine and 1- or 3-NO2-anilinoacridine derivatives in which mutagenesis was increased in uvrB strains and also when pKM101 was present. These compounds were slightly more toxic in the uvrB background, but less toxic when pKM101 was present in either the uvrB or wild-type backgrounds. Mutagenesis by most compounds was reduced by the polA1 mutation and virtually eliminated (except in the case of ICR191) by the polA3 mutation. Plasmid pKM101 occasionally enhanced mutagenesis in the polA1 strain, whereas in the polA3 it appeared to have no effect whatsoever. Again, there were no obvious differences in toxicity between Pol+ and Pol- strains.

Acridines↗

Metabolism of acridine by rat-liver enzymes.

Metabolism of acridine by S10 fractions from control adult male Sprague-Dawley rats produces mainly 9- acridone , apparently catalyzed by aldehyde oxidase ( ED1 .2.3.1). In contrast, the predominant metabolic product produced by the corresponding S10 fraction of PCB-induced liver enzymes is a dihydrodiol (either the 2,3- or 3,4-isomer) presumably derived from an epoxide. Several minor metabolites of unknown structure are also formed. During in vitro reactions aldehyde oxidase requires neither atmospheric oxygen nor NADPH. Acridine has been reported to be mutagenic to Salmonella typhimurium, but only in the absence of PCB-induced activating enzymes. It also has been reported to produce chromosomal aberrations in cultured Chinese hamster cells both with and without enzymatic activation. While a connection between aldehyde oxidase catalysis and mutagenic action of acridine has not been established, the extensive metabolic potential of this compound implies that complete description of mutagenicity will be difficult.

Acridines↗

Intracellular distribution of acridine derivatives in platelets and their suitability for cytoplasmic pH measurements.

The site and mechanism of accumulation of acridine derivatives into platelets and their isolated organelles were investigated. In addition, their suitability as indicators of cytoplasmic pH was analysed. Direct microscopic observation showed that quinacrine and 9-aminoacridine are concentrated inside organelles in platelets. Using fractionation studies, the acridine derivatives were found to accumulate particularly in dense and alpha-granules. Uptake into these organelles is driven by a pH differential across their membrane (acidic inside). Because of their cellular distribution, acridine derivatives were found to be poor indicators of cytoplasmic pH. In contrast, a poorly permeant dicarboxylated fluorescein derivative, generated in situ by cytosolic enzymes, is shown to be a more reliable probe of intracellular pH. The results are compared with previous reports of the use of 9-aminoacridine as a cytoplasmic pH probe in platelets and of quinacrine as a selective dense-granule marker.

Acridines↗

Selectivity of N-[2-(dimethylamino)ethyl]acridine-4-carboxamide towards Lewis lung carcinoma and human tumour cell lines in vitro.

N-[2-(Dimethylamino)ethyl]acridine-4-carboxamide (AC; NSC 601316) is a chemically novel antitumour agent which is thought to interact with DNA topoisomerase II and which has DNA binding properties which are distinct from other acridine derivatives such as amsacrine and its disubstituted analogue CI-921. AC is one of the most active agents, experimental or clinical, against the Lewis lung carcinoma in mice. AC is the first acridine derivative in our hands to show higher activity against cultured Lewis lung cells than against leukaemia lines. AC is more active against two human leukaemia cell lines (U-937 and Jurkat) than against a melanoma line (MM-96) and is inactive against the HT-29 human colon line. With all cell lines tested, cytotoxicity was higher at AC concentrations of 3-6 microM than at 15-20 microM. AC at a concentration of 20 microM inhibited the cytotoxicity of amsacrine and CI-921, but not that of another topoisomerase-directed drug doxorubicin. A Lewis lung line which had been cultured for a long period was less sensitive than a line freshly isolated from mice, but sensitivity of the cultured line recovered after it was multiply passaged in vivo. Long-term cultures may therefore be less appropriate than short-term cultures for predicting effectiveness of AC in vivo.

Acridines↗

A probe for intracellular concentrations of drugs: delayed fluorescence from acridine orange.

The aim of this work is to develop fluorescent probes that will indicate effective concentrations of therapeutic agents, or endogenous protectors, at important cellular sites. Acridine orange associates with nucleic acids and emits a 'delayed' fluorescence signal. This signal is quenched by oxidants such as oxygen, nitroaryl radiosensitizers, adriamycin and mitomycin-c, and reductants such as thiols, ascorbate and other radioprotectors. The quenching of the acridine orange delayed fluorescence reflects the effective concentration of these therapeutically-important oxidants and reductants near DNA. The relative concentration of basic radiosensitizers such as pimonidazole (Ro 03-8799) near the DNA is greater than that of misonidazole. Thiols quench the delayed fluorescence signal according to the degree of ionization of the thiol function; this may model the reactivity of thiols with guanine radical sites in DNA. Ascorbate and aminopyrine do not quench the delayed fluorescence from cells stained with acridine orange as these compounds are taken up by cells very inefficiently.

Acridine Orange↗

Synthesis and biological evaluation of modified acridines: the effect of N- and O- substituent in the nitrogenated ring on antitumor activity.

A series of new acridines has been prepared by cyclodehydration of N-(2,3-dihydro-1,4-benzodioxin-6-yl)anthranilic acid in acidic media following classical procedures. All these compounds have in common a dioxygenated ring fused to the acridine. The tetracyclic system possesses a linear or angular structure formed by intramolecular cyclisation. The last ring and the substituent of the system modify, in an interesting way, the antitumor activity of acridines. Several of the studied compounds displayed significant cytotoxic activity (inhibition of L1210 and HT-29 cell proliferation). The most cytotoxic compound 13a, shows more activity than m-AMSA in inhibiting L1210 and HT-29 cell proliferation and this compound has been selected as a development candidate for further evaluation. The activity results also indicate that the new 11-O-substituted compounds are of considerable interest with high levels of cytotoxic activity. The angular or non-linear dioxinoacridine 10 was equiactive with the linear structure 7. Pentacyclic analogues (14 and 15) were more cytotoxic than the tetracyclic compounds (up to twofold).

Acridines↗

Plasmodium yoelii: a differential fluorescent technique using Acridine Orange to identify infected erythrocytes and reticulocytes in Duffy knockout mouse.

Both human malarial parasite Plasmodium vivax and mouse malaria parasite Plasmodium yoelii use Duffy protein as the receptor for invasion and they preferentially invade reticulocytes. Recently, it has been shown that P. yoelii invades mouse reticulocytes by a Duffy independent pathway. Parasite invasion is generally visualized by time consuming staining procedures with dyes like Giemsa or Wright-Giemsa. Fluorochromatic dye like Acridine Orange has been used for instantaneous detection of parasites in RBCs. Acridine Orange binds to both DNA and RNA but with different emission spectra; and the binding can be distinguished with a fluorescent microscope using a green or a red filter, respectively. We have used this differential emission of Acridine Orange to determine P. yoelii invasion into erythrocytes and reticulocytes of Duffy positive and Duffy knockout mice. Moreover, we show that this method can be used to determine the maturity of reticulocytes in the peripheral blood of anemic mice.

Acridine Orange↗

Acridine orange staining for rapid diagnosis of Acanthamoeba keratitis.

Acanthamoeba keratitis is uncommon, but one of the most severe infectious diseases of the cornea. Delayed diagnosis or misdiagnosis as bacterial or herpes simplex keratitis leads to extensive corneal inflammation and profound visual loss. Therefore, accurate and rapid diagnosis of Acanthamoeba keratitis is essential for successful treatment and good prognosis. We evaluated the usefulness of acridine orange staining from corneal scrapings and contact lens solutions for the rapid diagnosis of four consecutive cases of Acanthamoeba keratitis. Gram stain and culture on nonnutrient agar plates with Escherichia coli overlay were also made. Corneal scrapings stained with acridine orange revealed yellow-to-orange polygonal, cystic structures consistent with the appearance of Acanthamoeba among inflammatory cells and the corneal epithelial cells. The contact lens case solutions of two patients also showed numerous cysts with double wall. Some organisms from the third patient were identified as Acanthamoeba castellani and others as Acanthamoeba lugdunensis. Based on the acridine orange staining results in four cases of Acanthamoeba keratitis, this stain is recommended as a simple and reliable method for the rapid diagnosis of this disease.

Acanthamoeba↗

Synthesis and immobilization of a novel acridine derivative on microparticulate silica. A study of its interactions with single-stranded oligonucleotides by high-performance liquid chromatography.

A novel approach for immobilizing acridine on 5-microns silica gel is described. The acridine moiety is functionalized with a carboxylic acid group at its reactive 9-position and activated, leading to 9-acridinylpropionic acid N-hydroxysuccinimide ester. This derivative is efficiently bound to the silica matrix through a primary aliphatic amine group at the end of a fifteen-atom spacer arm. The chromatographic properties of the final stationary phases, as evaluated with d(T)10 and d(A)10 at various pH values and organic solvent concentrations, resemble those of hydrophobic weak anion exchangers. When a secondary amine group is placed close to the acridine moiety in one of the packings, enhanced binding of the oligodeoxyribonucleotides is observed that goes beyond a purely additive effect.

Acridines↗

Inhibition of wheat embryo calcium-dependent protein kinase by acridines and azaacridines.

The inhibition of wheat Ca(2+)-dependent protein kinase (CDPK) by substituted acridines and substituted 5-, 6-, 7- and 8-azaacridines (5-AA, 6-AA, 7-AA and 8-AA) was examined. Of a total of 71 substituted acridines and azaacridines examined, only 20 have IC50 values for wheat CDPK of less than 200 microM. Of these, effective compounds all have neutral or basic 4-substituents, except for 2,7-dibromo-4-carboxy-5-AAO (IC50 73 microM), the carboxymethyl ester of which is a much better inhibitor (IC50 20 microM). There is a large aza position effect so that various 4-substituted azaacridines can be either very active or very poor inhibitors depending upon the azaacridine nucleus substituted. One of the most potent inhibitors found is the 8-AA 4-N-(2-dimethylaminoethyl)carboxamide (4-P) derivative (IC50 1.5 microM), but the corresponding 4-substituted acridine analogue is a very poor inhibitor. Other potent inhibitors found include 1-nitro-4-P-8-AA (IC50 4 microM) and 7-bromo-4-methyl-5-AA (IC50 0.7 microM). These potent and relatively specific CDPK inhibitors may be useful in obtaining evidence for CDPK involvement in plant cell responses to specific signals.

Acridines↗

Interactions of chlorophyllin with acridine orange, quinacrine mustard and doxorubicin analyzed by light absorption and fluorescence spectroscopy.

The present study was designed to estimate the ability of chlorophyllin (CHL) to interact with two acridine mutagens, quinacrine mustard (QM) and acridine orange (AO), and with the antitumor anthracycline doxorubicin (Dox). To this end, aqueous solutions of QM, AO or Dox during titration with CHL were subjected to spectrophotometry and spectrofluorimetry to detect possible interactions between these reagents. The data indicate that CHL forms complexes with AO, QM or Dox in these solutions. The presence of the complexes was manifested by a bathochromic shift of the absorption spectra, as well as by strong quenching of the fluorescence of each of these mutagens in the presence of CHL. CHL, thus, may serve as an interceptor of these mutagenic acridines in different in vivo or in vitro applications. Its ability to interact with Dox may potentially be utilized to detoxify patients overdosed with this or similar drugs.

Acridine Orange↗

In situ detection of apoptotic nuclei in the substantia nigra compacta of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated mice using terminal deoxynucleotidyl transferase labelling and acridine orange staining.

The neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was used to generate a dose-dependent cell death of dopaminergic nigral neurons in the C57B1 mouse. Mice were injected with a total cumulative dose of 150 mg/kg of MPTP delivered over five days and killed at different time points both during and after the toxin injections. Two independent histological methods were used to determine whether the dopaminergic nigral neurons died via an apoptotic mechanism. In situ end-labelling with terminal deoxynucleotidyl transferase was used on paraformaldehyde-fixed, serial, frozen sections to identity cells with double-stranded DNA breaks. Apoptotic cell death was found to be initiated within 72 h of the first injection of the neurotoxin and peaked 24 h after the final MPTP injection. The metachromatic fluorochrome, Acridine Orange, was used on alternate sections to provide structural confirmation of the nuclear chromatin "clumping" considered to be representative of apoptosis. Confocal laser imaging combined with deconvolution techniques was used to resolve the fluorescent signal emitted by the in situ Acridine Orange-DNA complexes. The number of Acridine Orange-stained nuclei demonstrating chromatin clumping was identical to that of the positive in situ end-labelled nuclei observed over a 25 day period. Based upon these two independent methods of assessing apoptosis in situ, we conclude that a 150 mg/kg dose of MPTP can elicit apoptotic cell death in nigral dopaminergic neurons of the C57B1 mouse.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

Early detection of Leishmania promastigotes in dog bone marrow cultures by acridine orange stain.

An acridine orange staining technique was evaluated in comparison with other well-known methods for the laboratory diagnosis of leishmaniasis. A higher number of promastigotes was found in Novy-MacNeal-Nicolle (NNN) cultures inoculated with canine bone marrow, when culture samples were stained with acridine orange vital stain, compared with those detected using either Giemsa staining or unstained wet mount examination. Based on our data the acridine orange stain is a useful and timely technique in reflecting the true numbers of microorganisms present in a culture and also enhances the visualization of the parasites. The present results warrant further studies with human samples from suspected leishmaniasis patients.

Acridine Orange↗

Acridine- and cholesterol-derivatized solid supports for improved synthesis of 3'-modified oligonucleotides.

New solid supports are described which allow the direct synthesis of oligonucleotides bearing either cholesterol or acridine at the 3'-terminus. A stereochemically defined amino diol was prepared by reduction of N-Cbz-hydroxy-L-proline. This linker molecule was first acylated with the desired conjugate molecule, then protected as the dimethoxytrityl ether. The remaining secondary hydroxyl group was succinylated and immobilized on a controlled-pore glass support. 3'-Modified oligodeoxynucleotides (ODNs) were prepared from these supports by using standard phosphoramidite coupling and deprotection conditions. A cholesterol-modified support was prepared from cholesterol chloroformate and the amino diol linker. Two types of acridine-modified solid supports were prepared from acridine tetrafluorophenyl esters with linker arms of different length. In an alternative synthesis of 3'-derivatized ODNs, these active esters were also utilized for acylation of a 3'-amine-modified ODN. A thermal denaturation study was done to determine the effect of the different linker arms on hybridization to a complementary ODN target. Facile synthesis and purification of the 3'-modified ODNs makes these functionalized solid supports especially useful for preparation of oligonucleotides bearing these and other modifications.

Acridines↗

Acridine conjugates of 3-clip-phen: influence of the linker on the synthesis and the DNA cleavage activity of their copper complexes.

To increase the DNA cleavage activity and the cell delivery of the bis(phenanthroline) DNA cleaver "3-Clip-Phen", conjugates between 3-Clip-Phen and the intercalators acridine and 6-chloro-2-methoxyacridine, through amino acid linkers of various length, were prepared. After complexation with CuCl(2), the ability of these conjugates to cleave phiX 174 DNA in the presence of a reductant and air was compared. The results indicated that (i) the coupling of 3-Clip-Phen to an acridine derivative increased the DNA cleavage efficiency of the copper complexes, (ii) the acridine derivatives were more active than 6-chloro-2-methoxyacridine derivatives, (iii) the linker length influenced cleavage efficiency, the highest DNA cleavage activity being obtained for an aminocaproic spacer.

Acridines↗