Antiulcerogenic and Antibacterial Effects of Chitosan Derivatives on Experimental Gastric Ulcers in Rats.

Gastric ulcer is an injury that develops on the lining of the stomach due to an imbalance between aggressive and defensive agents. Chitosan derivatives demonstrate promising biological activities in accelerating the healing activity of gastric lesions. Thus, this study aimed at investigating the healing activity of gastric lesion, induced by acetic acid (80%), of the chitosan derivative with acetylacetone (Cac) modified with ethylenediamine (Cacen) or diethylenetriamine (Cacdien). The biological activity was determined based on cytotoxicity, antibacterial activity, and gastroprotective activities. The results showed no significant difference in the cytotoxicity, a better antibacterial activity against S. aureus and E. coli, and a positive result on the healing of gastric lesions of the materials (Cac 18.4%, Cacen 55.2%, and Cacdien 68.1%) compared to pure chitosan (50.7%). Therefore, the results indicate that derivatives of chitosan are promising biomaterials for application in the control of lesions on the gastric mucosa.

Biological properties of chitosan derivatives associated with the ceftazidime drug.

Chitosan has become promising as a biomaterial because of its biocompatible, biodegradable nature and non-toxic. The biochemical and antioxidant properties of chitosan modified with acetylacetone and ethylenediamine (Cacen) or diethylenetriamine (Cacdien) associated with ceftazidime (F) were investigated. Chitosan was characterized using Elemental Analysis (CHN), Thermal Analysis (TG/DTG/DSC), X-Ray Diffractometry (XRD), and was investigated an in vitro hemolytic cytotoxicity test, Artemia saline larvae for toxicity and in vitro antioxidant activity by DPPH (2,2-diphenyl-1-picrylhydrazyl). The chemical modification was confirmed by CHN, XRD and TG. The Cacen, Cacdien, CacenF and CacdienF derivatives presented high percentages of nitrogen (7.6%, 7.9%, 14.1% and 19.2%, respectively), confirming the modification and drug adsorption. The average molecular weight of chitosan and its derivatives were 132 kDa, with very few variations after modification. This incorporation decreased in the crystallinity index of Cacen (7.1%) and Cacdien (4.3%), as well as the incorporation of the drug (CacenF 0.3% and CacdienF 3.4%). FTIR spectra showed bands at 1580-1654 cm-1 referring to carbonyl and imine group and bands at 3500-3300 and 1462-1264 cm-1 related to vibration and deformation the amine group. 13C NMR spectroscopy was observed new peaks in carbonyl and imine regions (170-200 ppm). The thermal stability of the derivatives without the drug improved according to TG/DTG/DSC analysis, however there were decreased in the derivatives with the drug. The biocompatibility of the derivatives was confirmed by the low hemolytic rate (<5%), non-toxic on Artemia salina (LD50%>3000 ppm), and significant index (1-34%) of antioxidant activity. The results demonstrated that chitosan and its derivatives are promising biomaterials.

Use of Kisser glycerol gelatin to prepare microscope slides of Phlebotomine sandflies (Diptera: Psychodidae).

INTRODUCTION: Appropriate preservation of specimens is important for taxonomic identification. In sandfly research, various methods have been used for slide preparation; however, high cost, low commercial availability, and associated hazards make their use impossible in some studies. Therefore, the efficacy of Kisser glycerol gelatin for sandfly slide preparation was tested. METHODS: Kisser glycerol gelatin, as a substitute for Canada balsam and Berlese's fluid, was used for mounting sandflies. RESULTS: Forty-two mounted specimens were created and maintained even after 14 months. CONCLUSIONS: Use of Kisser glycerol gelatin is simple and efficient for preparing microscope slides of sandflies.

Use of Kisser glycerol gelatin to prepare microscope slides of Phlebotomine sandflies (Diptera: Psychodidae)

Abstract INTRODUCTION: Appropriate preservation of specimens is important for taxonomic identification. In sandfly research, various methods have been used for slide preparation; however, high cost, low commercial availability, and associated hazards make their use impossible in some studies. Therefore, the efficacy of Kisser glycerol gelatin for sandfly slide preparation was tested. METHODS: Kisser glycerol gelatin, as a substitute for Canada balsam and Berlese's fluid, was used for mounting sandflies. RESULTS: Forty-two mounted specimens were created and maintained even after 14 months. CONCLUSIONS: Use of Kisser glycerol gelatin is simple and efficient for preparing microscope slides of sandflies.