ผลกระทบของการเหยียบย่ำต่อโครงสร้างและความหนาแน่นสังคมของแมลงน้ำ

Thesis (M.Sc., Ecology)--Prince of Songkla University, 199

Chitosan Films: A Potential Local Drug Delivery System for Antibiotics

Local antibiotic delivery is an emerging area of study designed to provide alternative methods of treatment to clinicians for compromised wound sites where avascular zones can prevent the delivery of antibiotics to the infected tissue. Antibiotic-loaded bone cement is the gold standard for drug-eluting local delivery devices but is not ideal because it requires a removal surgery. Chitosan is a biocompatible, biodegradable polymer that has been used in several different drug delivery applications. We evaluated chitosan as a potential localized drug delivery device. We specifically determined if chitosan could elute antibiotics in an active form that would be efficacious in inhibiting S. aureus growth. Elution of amikacin was 24.67 ± 2.35 μg/mL (85.68%) after 1 hour with a final cumulative release of 27.31 ± 2.86 μg/mL (96.23%) after 72 hours. Elution of daptomycin was 10.17 ± 3.83 μg/mL after 1 hour (31.61% release) and 28.72 ± 6.80 μg/mL after 72 hours (88.55%). The data from the elution study suggested effective release of amikacin and daptomycin. The activity studies indicated the eluants inhibited the growth of S. aureus. Incorporating antibiotics in chitosan could provide alternative methods of treating musculoskeletal infections

Use of growth factors to improve muscle healing after strain injury

Muscle injuries represent a large number of professional and recreational sports injuries. Muscle strains habitually occur after an eccentric contraction, which often leads to an injury located in the myotendinous junction. Treatment varies widely, depending on the severity of the trauma, but has remained limited mostly to rest, ice, compression, elevation, antiinflammatory drugs, and mobilization. The authors' research group aims to develop new biologic approaches to improve muscle healing after injuries, including muscle strains. To achieve this goal, the authors investigated several parameters that will lead to the development of new strategies to enhance muscle healing. The authors first evaluated natural muscle healing after strain injuries and showed that muscle regeneration occurs in the early phase of healing but becomes impaired with time by the development of tissue fibrosis. Several growth factors capable of improving muscle regeneration were investigated; basic fibroblast growth factor, insulin-like growth factor, and nerve growth factors were identified as substances capable of enhancing muscle regeneration and improving muscle force in the strained injured muscle. The current study should aid in the development of strategies to promote efficient muscle healing and complete recovery after strain injury

Characterization of local delivery with amphotericin B and vancomycin from modified chitosan sponges and functional biofilm prevention evaluation

Polymicrobial musculoskeletal wound infections are troublesome complications and can be difficult to treat when caused by invasive fungi or bacteria. However, few local antifungal delivery systems have been studied. Chitosan and polyethylene glycol (PEG) sponge local antifungal delivery systems have been developed for adjunctive therapy to reduce musculoskeletal wound contamination. This study evaluated the effects of blending PEG, at 6,000 or 8,000 g/mol, with chitosan in sponge form on in vitro amphotericin B and vancomycin elution, eluate activity, cytocompatibility, and in vivo prevention of a bacterial biofilm. Blended chitosan sponges released both amphotericin B and vancomycin in vitro. All tested amphotericin B eluates remained active against Candida albicans, and vancomycin eluates from blended sponges maintained activity against Staphylococcus aureus. Amphotericin B eluates obtained after 1 h from blended sponges elicited 62-95% losses in fibroblast viability, but 3 h eluates only caused 22-60% decreases in viability. In a Staphylococcus aureus infected mouse catheter biofilm prevention model, vancomycin loaded chitosan/PEG 6000 sponge cleared bacteria from 100% of the catheters, with reduced clearance rate observed in other sponges. These results indicate that the chitosan/PEG blended sponges have potential for local antifungal and/or antibiotic combination delivery as an adjunctive therapy to prevent wound infections