BACKGROUND: It has been reported that chitosan can inhibit scar formation and promote wound healing. Medical invisible antimicrobial film is a new type of membrane materials which comprises chitosan as ground substance.OBJECTIVE: To determine the inhibitory effects of medical invisible antimicrobial film on the operative incision scar, and to observe its effects on wound healing.DESIGN, TIME AND SETTING: A controlled animal study was conducted at the IVC Experimental Animal Room, West China School of Pharmacy, Sichuan University from August to October 2007.MATERIALS: Medical invisible antimicrobial film stock solution was colorless transparent sticking solution, which formed colorless transparent film following spray painting (specification: 40 mL), provided by Chengdu Chaojl Technology Co., Ltd. (lot number 070501).METHODS: A total of 16 healthy Sprague Dawley rats aged 20 to 23 days were selected. Full linear skin incisions were operated in aseptic condition. After operation, the experimental group (right side) was sprayed medical invisible antimicrobial film 0.5 mL/time, once a day, for totally 3 days. The control group (left side) received an equal volume of 0.9% sodium chloride injection, with natural cure.MAIN OUTCOME MEASURES: At 3, 7 and 14 days following surgery, incision skin specimens were obtained, and subjected to hematoxylin-eosin staining and Masson staining was applied to observe wound healing and the formation of scar, then the scar area was analyzed.RESULTS: The scar relative mean area of control group was 154 069±51 356 and the experimental group was 98 200±34 719 on the postoperative 14~(th) day. The two groups were significantly different (P < 0.05). At 14 days following surgery, optical microscope showed that the experiment group had less collagen fibers and fibroblast accumulation. At 3 days, compared with the control group, the experimental group had less epithelization period, more granulation tissue and less inflammatory cell infiltration.CONCLUSION: The medical invisible antimicrobial film has inhibitory effect of the formation of operative incision scar, and no influence on wound healing of operative incision.

Fumonisin B1 (FB1) is a carcinogenic mycotoxin found in commodities such as corn and corn-originated products. An aptamer-based method for detection of FB1 was developed using the fluorescent dye PicoGreen, which can recognize and bind double-stranded DNA. A peak fluorescence of PicoGreen was obtained in 15 min in the presence of FB1 aptamer, which formed a double-stranded hybridizer DNA with its complementary strand. The excitation and emission wavelengths for PicoGreen detection were 480 nm and 520 nm, respectively. The sensitivity of this aptamer/PicoGreen-based method was 0.1 μg/L. This method showed a good linearity for FB1 concentration ranging from 0.1 to 1 μg/L. The entire detection procedure for FB1 could be completed within 40 min. No cross reactions were observed with any other mycotoxins against aflatoxin B1, ochratoxin A, citrinin and zearalenone, demonstrating high specificity towards FB1 aptamer. Agreement between commercial, antibody-based enzyme-linked immunosorbent assay (ELISA) kit and aptamer method was excellent with a kappa value of 0.857. Taken together, this aptamer/PicoGreen-based method is more cost-effective, time-saving and useful than ELISA for detection of FB1.
Aflatoxin B1 ; Enzyme-Linked Immunosorbent Assay ; Fluorescence ; Fluorescent Dyes ; chemistry ; Fumonisins ; analysis ; Mycotoxins ; analysis ; Ochratoxins ; Organic Chemicals ; chemistry ; Staining and Labeling ; Zea mays

We aimed to obtain the recombinant aminopeptidase encoded by Listeria monocytogenes (L. monocytogenes) gene lmo1711, and characterized the enzyme. First, the amino acid sequences of Lmo1711 from L. monocytogenes EGD-e and its homologues in other microbial species were aligned and the putative active sites were analyzed. The putative model of Lmo1711 was constructed through the SWISS-MODEL Workspace. Then, the plasmid pET30a-Lmo1711 was constructed and transformed into E. coli for expression of the recombinant Lmo1711. The his-tagged soluble protein was purified using the nickel-chelated affinity column chromatography. With the amino acid-p-nitroaniline as the substrate, Lmo1711 hydrolyzed the substrate to free p-nitroaniline monomers, whose absorbance measured at 405 nm reflected the aminopeptidase activity. The specificity of Lmo1711 to substrates was then examined by changing various substrates, and the effect of metal ions on the catalytic efficiency of this enzyme was further determined. Based on the bioinformatics data, Lmo1711 is a member of the M29 family aminopeptidases, containing a highly conserved catalytic motif (Glu-Glu-His-Tyr-His-Asp) with typical structure arrangements of the peptidase family. The recombinant Lmo1711 with a size of about 49.3 kDa exhibited aminopeptidase activity and had a selectivity to the substrates, with the highest degree of affinity for leucine-p-nitroaniline. Interestingly, the enzymatic activity of Lmo1711 can be activated by Cd²⁺, Zn²⁺, and is strongly stimulated by Co²⁺. We here, for the first time demonstrate that L. monocytogenes lmo1711 encodes a cobalt-activated aminopeptidase of M29 family.