An extracellular matrix (ECM) derived from the submucosa of the porcine small intestine (SIS) has been shown to induce angiogenesis and host tissue remodeling when used as a xenogeneic bioscaffold in animal models of wound repair. In the present study, we compared the in vitro effects of SIS ECM extracts to several purified angiogenic growth factors on human dermal microvascular endothelial cell (HMEC) growth patterns. The SIS ECM was shown to induce tube formation from HMEC in a three-dimensional fibrin-based angiogenesis assay in a manner similar to that caused by the addition of vascular endothelial growth factor (VEGF). This tube formation was blocked in the presence of anti-VEGF neutralizing antibody. Western blots and ELISA procedures showed that the SIS ECM contains as much as 0.77 ng VEGF/g SIS. The closely related endothelial cell mitogen, platelet-derived growth factor (PDGF), was not detectable in the SIS extracts. We conclude that VEGF is present in the SIS extracellular matrix. The role of VEGF in SIS-induced wound repair remains unknown, but its presence in the ECM makes it a possible contributor to the angiogenic effect of SIS when this ECM is used as a tissue repair scaffold in animal models of wound repair.

A wound is damage of a tissue usually caused by laceration of a membrane, generally the skin. Wound healing is accomplished in three stages in healthy individuals, including inflammatory, proliferative, and remodeling stages. Healing of wounds normally starts from the inflammatory phase and ends up in the remodeling phase, but chronic wounds remain in an inflammatory stage and do not show progression due to some specific reasons. Chronic wounds are classified in different categories, such as diabetic foot ulcer (DFU), venous leg ulcers (VLU) and pressure ulcer (PU), surgical site infection (SSI), abscess, or trauma ulcers. Globally, the incidence rate of DFU is 1-4 % and prevalence rate is 5.3-10.5 %. However, colonization of pathogenic bacteria at the wound site is associated with wound chronicity. Most chronic wounds contain more than one bacterial species and produce a synergetic effect that results in previously non-virulent bacterial species becoming virulent and causing damage to the host. While investigating bacterial diversity in chronic wounds, Staphylococcus, Pseudomonas, Peptoniphilus, Enterobacter, Stenotrophomonas, Finegoldia, and Serratia were found most frequently in chronic wounds. Recently, it has been observed that bacteria in chronic wounds develop biofilms that contribute to a delay in healing. In a mature biofilm, bacteria grow slowly due to deficiency of nutrients that results in the resistance of bacteria to antibiotics. The present review reflects the reasons why acute wounds become chronic. Interesting findings include the bacterial load, which forms biofilms and shows high-level resistance toward antibiotics, which is a threat to human health in general and particularly to some patients who have acute wounds.

The extracellular matrix (ECM) of porcine small intestinal submucosa (SIS) has been shown to serve as a resorbable scaffold for tissue repair and remodeling in several body locations including the urinary bladder. The rate of resorption and extent of SIS degradation are unknown. Nine dogs were divided into three equal groups. Approximately 40% of the anterior dome of the urinary bladder was resected in each dog and replaced with porcine SIS. One group of dogs was sacrificed at each of 4, 8, and 12 weeks after surgery and the fate of the implanted SIS determined by immunohistochemical methods using a monoclonal antibody specific for porcine-derived SIS. By 4 weeks after surgery, only scattered remnants of SIS were present in the remodeled urinary bladder and these positively staining foci were surrounded by an extensive new host derived ECM and neovascularization. There was a continuous layer of transitional epithelium on the luminal surface by 4 weeks. No evidence for the originally implanted SIS could be found at either 8 or 12 weeks and bundles of organized smooth muscle cells were present at the operative site. In summary, SIS is rapidly and extensively degraded when used as a bioscaffold for augmentation cystoplasty in the dog model.

BackgroundDental erosion has been investigated in developed and developing countries and the prevalence varies considerably in different countries, geographic locations, and age groups. With the lifestyle of the Chinese people changing significantly over the decades, dental erosion has begun to receive more attention. However, the information about dental erosion in China is scarce. The purpose of this study was to explore the prevalence of dental erosion and associated risk factors in 12-13-year-old school children in Guangzhou, Southern China.MethodsThis cross-sectional survey was performed by two trained, calibrated examiners. A stratified random sample of 12-13-year-old children (774 boys and 725 girls) from 10 schools was examined for dental erosion using the diagnostic criteria of Eccles and the index of O'Sullivan was applied to record the distribution, severity, and amount of the lesions. Data on the socio-economic status, health behaviours, and general health involved in the etiology of dental erosion were obtained from a self-completed questionnaire. The analyses were performed using SPSS software.ResultsAt least one tooth surface with signs of erosion was found in 416 children (27.3%). The most frequently affected teeth were the central incisors (upper central incisors, 16.3% and 15.9%; lower central incisors, 17.4% and 14.8%). The most frequently affected surface was the incisal or occlusal edge (43.2%). The loss of enamel contour was present in 54.6% of the tooth surfaces with erosion. Of the affected tooth surfaces, 69.3% had greater than one-half of the tooth surface was affected. The results from logistic regression analysis demonstrated that the children who were female, consumed carbonated drinks once a week or more, and those whose mothers were educated to the primary level tended to have more dental erosion.ConclusionsDental erosion in 12-13-year-old Chinese school children is becoming a significant problem. A strategy of offering preventive care, including more campaigns promoting a healthier lifestyle for those at risk of dental erosion should be conducted in Chinese children and their parents.

Loss-of-function mutagenesis is an important tool used to characterize gene functions, and the CRISPR-Cas9 system is a powerful method for performing targeted mutagenesis in organisms that present low recombination frequencies, such as the serotype D strains of Cryptococcus neoformans. However, when the CRISPR-Cas9 system persists in the host cells, off-target effects and Cas9 cytotoxicity may occur, which might block subsequent genetic manipulation. Here, we report a method of spontaneously eliminating the CRISPR-Cas9 system without impairing its robust editing function. We successfully expressed single guide RNA under the driver of an endogenous U6 promoter and the human codon-optimized Cas9 endonuclease with an ACT1 promoter. This system can effectively generate an indel mutation and efficiently perform targeted gene disruption via homology-directed repair by electroporation in yeast. We then demonstrated the spontaneous elimination of the system via a cis arrangement of the CRISPR-Cas9 expression cassettes to the recombination construct. After a system-mediated double crossover, the CRISPR-Cas9 cassettes were cleaved and degraded, which was validated by Southern blotting. This ‘suicide’ CRISPR-Cas9 system enables the validation of gene functions by subsequent complementation and has the potential to minimize off-target effects. Thus, this technique has the potential for use in functional genomics studies of C. neoformans.

Small intestinal submucosa (SIS) is a naturally occurring, acellular biomaterial derived from porcine jejunum, which promotes constructive tissue remodeling when applied as a xenogeneic graft material. Galactosyl-alpha(1,3)galactose (Gal) is a cell-associated epitope responsible for hyperacute rejection of porcine whole-organ xenografts in primates. Because SIS is harvested from porcine tissue, it may contain the Gal epitope. The goals of this study were to determine if Gal is present in SIS and, if it is present, to determine if human serum complement can be activated in vitro following exposure to porcine-derived SIS. SIS was probed for Gal by immunohistochemical methods and by lectin-peroxidase staining. SIS stained strongly positive with human serum, which contains naturally occurring antibodies to Gal, followed by anti-immunoglobulin G (IgG) or anti-IgM peroxidase conjugate. Blocking with the lectin I-B(4), which is specific for the Gal epitope, decreased the intensity of staining. Exposure of SIS to alpha-galactosidase reduced staining to negligible amounts. The Gal epitope is distributed transmurally throughout the SIS material. Subtyping of the immunoglobulins that bind to SIS showed that IgG(2) is the major immunoglobulin of human plasma that binds to SIS. SIS did not activate complement in vitro as measured by radioimmunoassay for C3a.

In this study, we demonstrated that the effect of resveratrol on apoptosis is due to inhibiting miR-21 regulation of BCL-2 expression.

Melanin plays an important role in regulating various biological processes in many fungi. However, its biological role in conidiation remains largely elusive. We report here that conidia production, morphogenesis, integrity, germination and their viability in Pestalotiopsis microspora require the polyketide-derived melanin. A polyketide synthase gene, pks1, was identified and demonstrated responsible for melanin biosynthesis in this fungus. A targeted deletion mutant strain Δpks1 displayed a defect in pigmentation of conidia and had an albino colonial phenotype. Interestingly, Δpks1 produced approximately 6-fold as many conidia as the wild type did, suggesting a negative modulation of melanin on conidia production in this fungus. Moreover, the conidia failed to develop into the normal five-cell morphology, rather the three main-body cells separated via constriction at the original septum position to generate three independent mutant conidia. This result suggests a novel role of melanin in the formation of the multi-cellular conidia. Germ tubes could develop from the three different types of mutant conidia and kept elongating, despite a significantly lower germination rate was observed for them. Still more, the unpigmented conidia became permeable to Calcofluor White and DAPI, suggesting the integrity of the conidia was impaired. Deliberate inhibition of melanin biosynthesis by a specific inhibitor, tricyclazole, led to a similar phenotypes. This work demonstrates a new function of fungal melanin in conidial development.