Fabricating antimicrobial peptide-immobilized starch sponges for hemorrhage control and antibacterial treatment.

It is important to control immediate hemorrhage and prevent infection simultaneously in the wound management. However, most of hemostatic materials are associated with low efficiency of hemostasis, poor biocompatibility and lack of antimicrobial properties. A kind of starch-based macroporous sponges (KR-Sps) immobilized covalently with antimicrobial peptide KR12 using highly efficient thiol-ene photo click reaction were developed. The physical properties of these sponges could be fine-tuned by varying the ratio of modified starch/HS-PEG-SH and the polymer concentration. The in vitro and vivo results demonstrated that KR-Sps induced thrombosis, shortened clotting time and reduced the blood loss at bleeding site. Besides, KR12 immobilized sponge exhibited inherent antimicrobial properties against Gram (+) and (-) bacteria and methicillin-resistant Staphylococcus aureus (MRSA), which could maintain at least 5 days. Therefore, KR-Sps were believed to be an excellent candidate as hemostatic and antimicrobial product for the intraoperative wound management.

Banana starch nanocomposite with cellulose nanofibers isolated from banana peel by enzymatic treatment: In vitro cytotoxicity assessment.

The potential use of cellulose nanofibers (CNFs) as a reinforcing agent in banana starch-based nanocomposite films was investigated. CNFs were isolated from banana peel (Musa paradisiaca) by enzymatic hydrolysis. Banana starch-based nanocomposite films were prepared with CNFs using the casting method. CNFs effect on cell viability and on nanocomposite films properties' was investigated. The cytotoxicity of CNFs was assessed on Caco-2 cell line. CNFs were not cytotoxic at 50-2000 µg/mL. However, CNFs above 2000 µg/mL significantly decreased cell viability. Topography analysis showed that the incorporation of CNFs modified the film structure. The nanocomposites exhibited a complex structure due to strong interactions between CNFs and starch matrix, promoting a remarkable improvement on mechanical and water barrier properties, opacity and UV light barrier compared to the control film. CNFs can offer a great potential as reinforcing material for starch-based nanocomposite films, producing a value-added food packaging from a waste material.

Role of oxidative tissue injury in the pathophysiology of experimentally induced equine laminitis: a comparison of 2 models.

BACKGROUND: Oxidative stress reportedly plays a role in sepsis-induced organ dysfunction and failure in many species. In septic horses, laminae are targeted; evidence of laminar oxidative stress has been reported experimentally in the black walnut extract (BWE) model. Carbohydrate (CHO)-induced laminitis may be more similar to clinical sepsis-related laminitis than the BWE model in that animals with CHO-induced disease commonly develop laminar failure. The role of oxidative stress in the CHO model remains unknown. HYPOTHESIS/OBJECTIVES: Markers of oxidative stress will be increased in laminae from horses with BWE- and CHO-induced laminitis. ANIMALS: Banked laminar tissue from various time points from animals subjected to BWE (n = 15) and CHO (n = 20) protocols. METHODS: Laminar 4-hydroxynonenal (4-HNE) and protein carbonyl content were evaluated by slot blot analysis. Laminar 3-nitrotyrosine (3-NT) immunohistochemistry was performed. RESULTS: The number of laminar 3-NT (+) cells was increased at developmental and Obel grade 1 (OG1) time points in the BWE model (versus control [CON]; P= .013) and lower in OG1 tissues than CON in the CHO model (P = .04). No change in 4-HNE content was observed in the CHO model, and no increase in laminar protein carbonyl content was present in either model (P > .05). CONCLUSIONS AND CLINICAL IMPORTANCE: These results do not support a prominent role for oxidative stress at examined time points in CHO-overload laminitis and support transient oxidative stress in the BWE model. Tissue oxidation does not appear to be a central early pathophysiologic event in CHO-associated laminitis.

Synthesis and evaluation of novel bioactive composite starch/bioactive glass microparticles.

The aim of the development of composite materials is to combine the most desired properties of two or more materials. In this work, the biodegradable character, good controlled-release properties, and natural origin of starch-based biomaterials are combined with the bioactive and bone-bonding properties of bioactive glass (BG). Novel, bioactive composite starch-BG microparticles were synthesized starting from a blend of starch and polylactic acid (50%/50% wt) with BG 45S5 powder using a simple emulsion method. Morphological and chemical characterization showed that these particles exhibited a spherical morphology with sizes up to 350 microm and that BG 45S5 was incorporated successfully into the composite particles. Upon immersion in a solution simulating body fluids, for periods up to 3 weeks, their bioactive nature was confirmed, as a calcium-phosphate layer resembling biological apatite was formed onto their surface. The short-term cytotoxicity of these materials was also tested by placing 24-h leachables of the materials extracted in culture medium in contact with a fibroblastic cell line (L929) up to 72 h. At this time period, two biochemical tests--MTT and total protein quantification--were performed. The results showed that these materials are not cytotoxic. These results constitute the basis of future encapsulation studies using bone-acting therapeutic agents such as bone morphogenetic proteins or other bone-relevant factors. The particles developed here may be very useful for applications in which controlled release, degradability, and bone-bonding ability are the main requirements.

Wheat bran suppresses potato starch--potentiated colorectal tumorigenesis at the aberrant crypt stage in a rat model.

BACKGROUND & AIMS: Starch that escapes digestion in the small intestine (resistant starch [RS]) may act similarly to nonstarch polysaccharides in the colon. The aim of this study was to examine the effect of raw potato starch alone and in combination with wheat bran on tumor development and precancer events in a rat model of colorectal cancer. METHODS: Three groups of rats received either a low-RS/low-fiber ("basic") diet, the basic diet containing raw potato starch as 20% of carbohydrate content, or the potato starch diet plus 10% of "wheat bran" fiber. Epithelial proliferation, aberrant crypt foci (ACF), and tumors were measured 6 and 20 weeks after a 10-week course of dimethylhydrazine. RESULTS: Rats on the potato starch diet had tumors more frequently and had larger tumors than rats consuming the wheat bran or basic diets. Parallel effects on the density of ACF were found 6 weeks after the carcinogen. Although epithelial proliferation was significantly enhanced by potato starch compared with the basic diet, the addition of wheat bran did not suppress this enhancement. CONCLUSIONS: This type-2 RS enhances epithelial proliferation, ACF density, and tumor formation. The addition of wheat bran to an RS-containing diet suppresses tumorigenesis, acting on events responsible for the formation of ACF but not the events controlling the hyperproliferative phase.

Effects of a dietary load of acid or base on changes induced by lactose in rats.

Feeding lactose or other slowly digestible carbohydrates to adult mammals may induce a variety of effects including hyperplasia and neoplasia. The most fundamental effect probably is the increased production in the large intestine of short-chain fatty acids (SCFA) resulting from increased fermentation of carbohydrate residues. To find out whether the increased production of these acidic compounds is involved in the induction of certain alterations caused by low-digestibility carbohydrates, the modifying effects of an acidifying (NH4Cl) or an alkalizing (KHCO3) diet supplement on lactose-induced changes in rats were studied. Three groups of 50 rats per sex were fed a 20% lactose diet unsupplemented or supplemented with 1% NH4Cl or 2% KHCO3, for at most 2.5 yr. One control group was fed the basal diet which contained wheat starch instead of lactose. Feeding lactose resulted in wet faecal pellets, reduced pH of the faeces, higher intake of food and water, lower body weights, increased caecal weights and fewer deaths. These effects were not significantly modified by NH4Cl or KHCO3. Feeding lactose increased urinary calcium levels, the effect being enhanced by NH4Cl and reduced by KHCO3. Lactose also tended to increase blood values of alkaline phosphatase and to decrease those for bicarbonate and base excess. These tendencies were generally more marked with NH4Cl, and less marked or absent with KHCO3. In addition, rats fed lactose showed decreased severity of nephrosis, increased mineralization and hyperplasia of the renal pelvic epithelium, and relatively high incidences of Leydig cell hyperplasia and neoplasia. NH4Cl supplementation was associated with a relatively small number of single and multiple tumours, with decreased incidences of hyperplasia and mineralization of the renal pelvis epithelium and with a markedly reduced incidence of proliferative changes in the adrenal medulla. With the KHCO3 supplement the incidences of Leydig cell proliferation and of bladder tumours were relatively high. These findings, in particular the differences between the diet groups in urinary calcium levels and possibly also the variations in blood levels of alkaline phosphatase, bicarbonate and base excess, suggest that the acidic end products of carbohydrate fermentation (SCFA) act as an acid load on the body.