Abstract. Aloe vera has long been used as a traditional medicine for inducing wound healing. Gingival fibroblasts (GFs) play an important role in oral wound healing. In this study, we investigated the effects of acemannan, a polysaccharide extracted from Aloe vera gel, on GF proliferation; keratinocyte growth factor-1 (KGF-1), vascular endothelial growth factor (VEGF), and type I collagen production; and oral wound healing in rats. [ 3 H]-Thymidine incorporation assay and ELISA were used. Punch biopsy wounds were created at the hard palate of male Sprague Dawley rats. All treatments (normal saline; 0.1% triamcinolone acetonide; plain 1% Carbopol ® ; and Carbopol ® containing 0.5%, 1%, and 2% acemannan (w /w)) were applied daily. Wounded areas and histological features were observed at day 7 after treatment. From our studies, acemannan at concentrations of 2, 4, 8, and 16 mg/ml significantly induced cell proliferation (P<0.05). Acemannan concentrations between 2 -16 mg/ml significantly stimulated KGF-1, VEGF, and type I collagen expressions (P<0.05). Wound healing of animals receiving Carbopol ® containing 0.5% acemannan (w /w) was significantly better than that of the other groups (P<0.05). These findings suggest that acemannan plays a significant role in the oral wound healing process via the induction of fibroblast proliferation and stimulation of KGF-1, VEGF, and type I collagen expressions.

Our data suggest that acemannan could be a candidate biomolecule for periodontal tissue regeneration.

Aloe vera is a traditional wound healing medicine. We hypothesized acemannan, a polysaccharide extracted from Aloe vera gel, could affect bone formation. Primary rat bone marrow stromal cells (BMSCs) were treated with various concentrations of acemannan. New DNA synthesis, VEGF, BMP-2, alkaline phosphatase activity, bone sialoprotein, osteopontin expression, and mineralization were determined by [(3)H] thymidine incorporation assay, ELISA, biochemical assay, western blotting, and Alizarin Red staining, respectively. In an animal study, mandibular right incisors of male Sprague-Dawley rats were extracted and an acemannan treated sponge was placed in the socket. After 1, 2, and 4 weeks, the mandibles were dissected. Bone formation was evaluated by dual-energy X-ray absorptiometry and histopathological examination. The in vitro results revealed acemannan significantly increased BMSC proliferation, VEGF, BMP-2, alkaline phosphatase activity, bone sialoprotein and osteopontin expression, and mineralization. In-vivo results showed acemannan-treated groups had higher bone mineral density and faster bone healing compared with untreated controls. A substantial ingrowth of bone trabeculae was observed in acemannan-treated groups. These data suggest acemannan could function as a bioactive molecule inducing bone formation by stimulating BMSCs proliferation, differentiation into osteoblasts, and extracellular matrix synthesis. Acemannan could be a candidate natural biomaterial for bone regeneration.

To gain a more detailed picture of cryptococcosis in Thailand, a retrospective study of 498 C. neoformans and C. gattii isolates has been conducted. Among these, 386, 83 and 29 strains were from clinical, environmental and veterinary sources, respectively. A total of 485 C. neoformans and 13 C. gattii strains were studied. The majority of the strains (68.9%) were isolated from males (mean age of 37.97 years), 88.5% of C. neoformans and only 37.5% of C. gattii strains were from HIV patients. URA5-RFLP and/or M13 PCR-fingerprinting analysis revealed that the majority of the isolates were C. neoformans molecular type VNI regardless of their sources (94.8%; 94.6% of the clinical, 98.8% of the environmental and 86.2% of the veterinary isolates). In addition, the molecular types VNII (2.4%; 66.7% of the clinical and 33.3% of the veterinary isolates), VNIV (0.2%; 100% environmental isolate), VGI (0.2%; 100% clinical isolate) and VGII (2.4%; 100% clinical isolates) were found less frequently. Multilocus Sequence Type (MLST) analysis using the ISHAM consensus MLST scheme for the C. neoformans/C. gattii species complex identified a total of 20 sequence types (ST) in Thailand combining current and previous data. The Thai isolates are an integrated part of the global cryptococcal population genetic structure, with ST30 for C. gattii and ST82, ST83, ST137, ST141, ST172 and ST173 for C. neoformans being unique to Thailand. Most of the C. gattii isolates were ST7 = VGIIb, which is identical to the less virulent minor Vancouver island outbreak genotype, indicating Thailand as a stepping stone in the global spread of this outbreak strain. The current study revealed a greater genetic diversity and a wider range of major molecular types being present amongst Thai cryptococcal isolates than previously reported.

ABSTRACT. Tests for acute oral toxicity, eye irritation, corrosion and dermal toxicity of colloidal silver nanoparticles (AgNPs) were conducted in laboratory animals following OECD guidelines. Oral administration of AgNPs at a limited dose of 5,000 mg/kg produced neither mortality nor acute toxic signs throughout the observation period. Percentage of body weight gain of the mice showed no significant difference between control and treatment groups. In the hematological analysis, there was no significant difference between mice treated with AgNPs and controls. Blood chemistry analysis also showed no differences in any of the parameter examined. There was neither any gross lesion nor histopathological change observed in various organs. The results indicated that the LD 50 of colloidal AgNPs is greater than 5,000 mg/kg body weight. In acute eye irritation and corrosion study, no mortality and toxic signs were observed when various doses of colloidal AgNPs were instilled in guinea pig eyes during 72 hr observation period. However, the instillation of AgNPs at 5,000 ppm produced transient eye irritation during early 24 hr observation time. No any gross abnormality was noted in the skins of the guinea pigs exposed to various doses of colloidal AgNPs. In addition, no significant AgNPs exposure relating to dermal tissue changes was observed microscopically. In summary, these findings of all toxicity tests in this study suggest that colloidal AgNPs could be relatively safe when administered to oral, eye and skin of the animal models for short periods of time.KEY WORDS: acute toxicity, colloidal silver nanoparticles, dermal, eye, oral.J. Vet. Med. Sci. 73(11): 1417-1423, 2011 Engineered nanoparticles (NP) are defined as materials produced within the nanoscale range of 1-100 nm in length or diameter that exhibit unique novel properties of the structural integrity as well as physical and chemical properties [26]. Over the past few decades, nanomaterials have had a great impact and gained enormous attention in science, technology and business because of their potential for achieving specific processes and selectivity. Although the applications and benefits of these engineered nanomaterials are extensively and currently being widely used in modern technology and many commercial and medical sectors, there is still limited information concerning human health and environmental impacts. Several studies expected that nanoparticles could lead to unexpected health or environmental hazards because of their unique properties such as extremely high surface area and increased reactivity [7].Silver nanoparticles (AgNPs), one of the most commonly used metal-nanoparticles, have been known to have a wide range of applications including solar energy absorption coatings, chemical catalysts and especially antimicrobial agents. AgNPs have potentials for inhibitory and bactericidal effects as well as retarding the growth of mold, harmful spores and germs [5]. Compared to bulk silver metal, AgNPs are expected to have higher antimicrobial activity...