Genome Shuffling of Stenotrophomonas maltophilia OK-5 for Improving the Degradation of Explosive RDX (Hexahydro-1,3,5-trinitro-1,3,5-triazine).

A genome-shuffled Stenotrophomonas maltophilia strain showing the enhanced ability of RDX degradation was constructed, and its characteristics were compared with those of the wild-type one. The shuffled strain was able to completely degrade 25, 50, and 75 µM RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) within 10, 30, and 50 days, respectively. However, it took 30 and 70 days for the wild-type strain to degrade 25 and 50 µM RDX, respectively, and at day 70, the strain degraded only 67% of 75 µM RDX. The shuffled strain reached its maximum growth at 50-60 days and exhibited approximately 1.5-fold increased cell numbers. SEM revealed more severe damage on the surface of the wild-type cells compared to the genome-shuffled cells. The mRNA levels of dnaK and groEL encoding the heat shock proteins were increased by 2.5-fold and fourfold, and DnaK and GroEL proteins were more highly produced in the shuffled cells. In addition, the mRNA levels of pnrB encoding a TNT nitroreductase, and algA involved in exopolymer biosynthesis, were slightly higher in the shuffled strain, but not as high as those of dnaK and groEL. These results indicate that the genome shuffling rendered the shuffled cells more resistant to RDX stress. A proteomic comparison revealed changes in the production levels of certain proteins including nitrate and cell protection, particularly those involved in metabolism. These proteomic analyses provide clues for understanding the improved RDX degradation by the genome-shuffled S. maltophilia strain.

Characterization and proteomic analysis of the Pseudomonas sp. HK-6 xenB knockout mutant under RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) stress.

Pseudomonas sp. HK-6 is able to utilize RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) as its sole nitrogen source. The role of the xenB gene, encoding xenobiotic reductase B, was investigated using HK-6 xenB knockout mutants. The xenB mutant degraded RDX to a level that was 10-fold less than that obtained with the wild-type HK-6 strain. After 60 days of culture with 25 or 50 µM RDX, no residual RDX was detected in the supernatants of the wild-type aerobically grown cultures, whereas approximately 90 % of the RDX remained in the xenB mutant cultures. The xenB mutant bacteria exhibited a 10(2)-10(4)-fold decrease in survival rate compared to the wild-type. The expression of DnaK and GroEL proteins, two typical stress shock proteins (SSPs), in the xenB mutant increased after immediate exposure to RDX, yet dramatically decreased after 4 h of exposure. In addition, DnaK and GroEL were more highly expressed in the cultures with 25 µM RDX in the medium but showed low expression in the cultures with 50 or 75 µM RDX. The expression levels of the dnaK and groEL genes measured by RT-qPCR were also much lower in the xenB genetic background. Analyses of the proteomes of the HK-6 and xenB mutant cells grown under conditions of RDX stress showed increased induction of several proteins, such as Alg8, alginate biosynthesis sensor histidine kinase, and OprH in the xenB mutants when compared to wild-type. However, many proteins, including two SSPs (DnaK and GroEL) and proteins involved in metabolism, exhibited lower expression levels in the xenB mutant than in the wild-type HK-6 strain. The xenB knockout mutation leads to reduced RDX degradation ability, which renders the mutant more sensitive to RDX stress and results in a lower survival rate and an altered proteomic profile under RDX stress.

Retrospective multicenter cohort analysis of 621 cases of BellaGel silicone breast implants with study of physicochemical properties and surface topography.

This study aimed to assess the effectiveness and safety of BellaGel implants after implantation in Asian women and inform surgeons of another option for use in breast augmentation and reconstruction. This study was conducted in eight hospitals from November 27, 2015 to April 30, 2018. All patients underwent augmentation mammoplasty or implant-based breast reconstruction with BellaGel implants. Complication rates were compared between groups, and the cumulative hazard function was compared using the Kaplan-Meier survival analysis. Implants were grouped by surface type, and the cumulative hazard functions of total complication cases were compared. The biomechanical properties of the BellaGel implant and other company representative implants were tested using a mechanical testing machine, and surface topography was analyzed using a 3D laser scanning confocal microscope. There was a significant difference in the incidence of complications between the reconstruction (17.1%) and augmentation (4.7%) groups, but no significant difference in the complication rates of each group. There was no difference in the reoperation or revision rates between the groups. The log rank test showed a statistically significant difference in cumulative hazard function between the groups. Among the three types of implants (smooth, textured, and microtextured), the microtextured type had the lowest complication rate. The BellaGel microtexture implant had the highest maximal tensile load and displacement value. The BellaGel and Silksurface implants had the highest stored energy, although there was no significant difference. BellaGel implants can serve as a criterion for the selection of safe and effective implants among currently available implants.

Basic rheology of dermal filler.

Dermal injectables are the most popular material for facial enhancement, including volumizing and wrinkle correction. However, although hyaluronic acid is the most common component of dermal injectables, the character of hyaluronic acid products is quite variable. These materials can be described in terms of their viscoelastic properties using four parameters. In this article, the author would like to describe these properties in detail. Although many physicians consider this material to be convoluted, thoroughly understanding the characteristics of various injectables enables us to tailor procedures accordingly and to enhance the final results.

Bone Morphogenetic Protein 2-Conjugated Silica Particles Enhanced Early Osteogenic Differentiation of Adipose Stem Cells on the Polycaprolactone Scaffold.

Background: Silica particles (SPs) induce cell proliferation and osteogenic differentiation. We reported that SPs in the scaffold induced early stage osteogenic differentiation. Methods: A polycaprolactone (PCL) scaffold was fabricated with a 10 wt% SPs. The surface of PCL scaffold was coated with a 10 µg/mL collagen solution. Next, the scaffold was conjugated with 2 µM SPs, 2 µg/mL bone morphogenetic protein 2 (BMP2), or 2 µM BMP2-conjugated SPs (BCSPs). Green fluorescent protein-coupled BMP2 was applied to fabricate the scaffold. The fluorescence intensity was analyzed by confocal microscopy. The mRNA levels of the early osteogenic differentiation marker, alkaline phosphatase (ALP), were analyzed by real-time quantitative polymerase chain reaction. Levels of BMP2, RUNX2, ERK1/2, and AKT were assessed by western blotting. Results: ALP mRNA levels were significantly higher in the BCSP-conjugated scaffold than in the other scaffolds. In the early stage of osteogenic differentiation, the protein levels of BMP2, RUNX2, ERK1/2, and AKT in cells were significantly higher in the BCSP-conjugated scaffold than in other scaffolds. Thus, the BCSP composite scaffold induced rapid osteogenic differentiation. Conclusion: These results suggest that BCSP composite can be used to promote early stage osteogenic differentiation and show promise as a material for use in scaffolds for bone regeneration.

Biomechanical Properties and Biocompatibility of a Non-Absorbable Elastic Thread.

To date, extensive studies have been conducted to assess diverse types of sutures. But there is a paucity of data regarding biomechanical properties of commonly used suture materials. In the current experiment, we compared biomechanical properties and biocompatibility, such as tensile strength and elongation, the degree of bovine serum albumin (BSA) release, in vitro cytotoxicity and ex vivo frictional properties, between a non-absorbable elastic thread (NAT; HansBiomed Co. Ltd., Seoul, Korea) (NAT-R: NAT with a rough surface, NAT-S: NAT with a smooth surface) and the Elasticum® (Korpo SRL, Genova, Italy). The degree of tensile strength and elongation of Si threads was significantly higher in both the NAT-R and -S as compared with the Elasticum® (p < 0.05). Moreover, the degree of tensile strength and elongation of PET threads was significantly lower in both NAT-R and -S as compared with the Elasticum® (p < 0.05). Furthermore, the degree of tensile strength and elongation of braided Si/PET threads was significantly lower in NAT-S as compared with NAT-R and Elasticum® (p < 0.05). The degree of BSA release was significantly higher in the NAT-R as compared with Elasticum® and NAT-S throughout a 2-h period in the descending order (p < 0.05). The degree of cell viability was significantly higher in both NAT-R and -S as compared with Elasticum® (p < 0.05). The degree of coefficient of friction as well as the frictional force and strength was significantly higher in NAT-R as compared with NAT-S and Elasticum® (p < 0.05). NAT had a higher degree of biomechanical properties and biocompatibility as compared with Elasticum®. But further experimental and clinical studies are warranted to compare the efficacy, safety, and potential role as a carrier for drug delivery between NAT and Elasticum®.

Gluteal fold V-Y advancement flap for vulvar and vaginal reconstruction: a new flap.

BACKGROUND: Soft-tissue reconstruction following vulvar cancer resection is a difficult challenge because of the functional, locational, and cosmetic importance of this region. Although numerous flaps have been designed for vulvar reconstruction, each has its disadvantages. METHODS: The authors introduce the gluteal fold fasciocutaneous V-Y advancement flap for vulvovaginoperineal reconstruction after vulva cancer resection. This flap is supplied by underlying fascial plexus derived from perforators of the internal pudendal artery and musculocutaneous perforators of underlying muscle. The sensory supply of this flap comes from the posterior cutaneous nerve of the thigh and the pudendal nerve. An axis of V-shaped triangular flap is aligned to the gluteal fold. A total of 17 flaps were performed in nine patients. RESULTS: All flaps survived completely, with no complications except for small perineal wound disruption in three patients. CONCLUSIONS: This flap is thin, reliable, sensate, easy to perform, and has matched local skin quality and concealed donor-site scar on the gluteal fold. In addition, it can cover large vulvovaginal defects because it can be advanced farther as a result of the character of the gluteal fold area. In our experience, the gluteal fold fasciocutaneous V-Y advancement flap has proven very useful for vulvar reconstruction, especially at the point of donor-site scar, flap thickness, and degree of flap advancement.