Photo-enhancement of the mutagenicity of 9-anilinoacridine derivatives related to the antitumour agent amsacrine

Fluorescein as a topical fluorescent contrast agent for quantitative microendoscopic inspection of colorectal epithelium

Fiber bundle microendoscopic imaging of colorectal tissue has shown promising results, for both qualitative and quantitative analysis. A quantitative image quality control and image feature extraction algorithm was previously designed for quantitative image feature analysis of proflavine-stained ex vivo colorectal tissue. We investigated fluorescein as an alternative topical stain. Images of ex vivo porcine, caprine, and human colorectal tissue were used to compare microendoscopic images of tissue topically stained with fluorescein and proflavine solutions. Fluorescein was shown to be comparable for automated crypt detection, with an average crypt detection sensitivity exceeding 90% using a combination of three contrast limit pairs.

Honey: a potential therapeutic agent for managing diabetic wounds

Diabetic wounds are unlike typical wounds in that they are slower to heal, making treatment with conventional topical medications an uphill process. Among several different alternative therapies, honey is an effective choice because it provides comparatively rapid wound healing. Although honey has been used as an alternative medicine for wound healing since ancient times, the application of honey to diabetic wounds has only recently been revived. Because honey has some unique natural features as a wound healer, it works even more effectively on diabetic wounds than on normal wounds. In addition, honey is known as an "all in one" remedy for diabetic wound healing because it can combat many microorganisms that are involved in the wound process and because it possesses antioxidant activity and controls inflammation. In this review, the potential role of honey's antibacterial activity on diabetic wound-related microorganisms and honey's clinical effectiveness in treating diabetic wounds based on the most recent studies is described. Additionally, ways in which honey can be used as a safer, faster, and effective healing agent for diabetic wounds in comparison with other synthetic medications in terms of microbial resistance and treatment costs are also described to support its traditional claims.

Synthesis and antileishmanial activities of 4,5-di-substituted acridines as compared to their 4-mono-substituted homologues

Newly synthesized 4,5-di-substituted acridines were assessed for in vitro antileishmanial activities as compared to those of their 4-mono-substituted homologues. Mono-substituted acridines exhibited a weak specificity for Leishmania parasites. Di-substituted acridines, on the contrary, displayed interesting amastigote-specific activities through a mechanism of action that might not involve intercalation to DNA. This antileishmanial property, associated with a low antiproliferative activity towards human cells, led to the identification of a new class of promising acridine derivatives such as 4,5-bis(hydroxymethyl)acridine with a nonclassical mechanism of action based on the inhibition of Leishmania internalization within macrophages. In the meantime, the effects of experimental lighting on the biological properties of acridines were assessed: experimental lighting did not significantly improve the antileishmanial activity of the compounds since it produced a greater toxicity against human cells.

Wound colonization and infection: the role of topical antimicrobials

Infection and bacterial colonization are important factors in compromised wound healing, particularly in chronic wounds. The current "best practice" for controlling these factors is still unclear. Systemic antibiotics are generally accepted as being the preferred choice for treating infection, provided that ischaemia does not interfere. However, their widespread systemic and topical use is leading to the emergence of resistant bacterial strains such as methicillin-resistant Staphylococcus aureus. Colonization of wounds presents a double problem: possible delayed healing if out of balance with the immune system; and as a source for cross-infection. Managing colonization is not yet defined in best practice. The judicious use of dressings, notably those containing certain antiseptic agents, can be valuable in infection control and in promoting healing. This review states the case for taking the antiseptic route as part of the concerted approach to local wound management and infection control.

Mutagenic activities of azido analogues of amsacrine and other 9-anilinoacridines in Salmonella typhimurium and their enhancement by photoirradiation

Analogues of amsacrine and other 9-anilinoacridines, bearing azide groups at various positions, were tested for their mutagenic activity in five strains of Salmonella typhimurium, both before and after photoirradiation. Azido substitution at the 2- or 3-position of the acridine or the 1'-position of the aniline led to compounds which were active frameshift mutagens, as detected in strain TA1537. Photoirradiation enhanced both the mutagenicity and the cytotoxicity of the azido compounds. Analogues bearing two azido groups at either the 2,6- or 3,6-positions were less strongly mutagenic in the dark, and light activation led to a toxic but only weakly mutagenic product. The effects of photoirradiation were decreased by aniline ring substitution, and were essentially eliminated by additional methyl substitution in the acridine ring. Comparison of events in TA1537 and TA98 suggested that photoirradiation of the 2- or 3-azido compounds gave a product which was capable of forming covalent bonds with DNA. The azide-containing analogues readily formed single strand DNA breaks on irradiation in the presence of DNA, but the efficiency of this reaction varied considerably.