An Affordable Approach of Mesenchymal Stem Cell Therapy in Treating Perianal Fistula Treatment.

The application of stem cells to treat perianal fistula due to Crohn's disease has attracted a lot of interest in recent decades. Though still a popular procedure, the existing surgical methods may be an ideal form of therapy since the recurrence rate is high, which affects the quality of life badly. Stem cell therapy offers to be a better solution in treating PF, but the utilisation is often restricted because of the manufacturing cost. Hence in this review, the selection of suitable cell sources, the use of bioreactors and preconditioning MSCs as well as modified stem cells will be discussed for a more affordable as compared with the current MSC therapy towards PF. We anticipate that exploring these approaches may give a complete picture in understanding stem cells in order to make them effective and affordable for long-term therapeutic applications.

An overview of photocatalytic degradation: photocatalysts, mechanisms, and development of photocatalytic membrane.

Photocatalysis is an ecofriendly technique that emerged as a promising alternative for the degradation of many organic pollutants. The weaknesses of the present photocatalytic system which limit their industrial applications include low-usage of visible light, fast charge recombination, and low migration ability of the photo-generated electrons and holes. Therefore, various elements such as noble metals and transition metals as well as non-metals and metalloids (i.e., graphene, carbon nanotube, and carbon quantum dots) are doped into the photocatalyst as co-catalysts to enhance the photodegradation performance. The incorporation of the co-catalyst which alters the photocatalytic mechanism was discussed in detail. The application of photocatalysts in treating persistent organic pollutants such as pesticide, pharmaceutical compounds, oil and grease and textile in real wastewater was also discussed. Besides, a few photocatalytic reactors in pilot scale had been designed for the effort of commercializing the system. In addition, hybrid photocatalytic system integrating with membrane filtration together with their membrane fabrication methods had also been reviewed. This review outlined various types of heterogeneous photocatalysts, mechanism, synthesis methods of biomass supported photocatalyst, photocatalytic degradation of organic substances in real wastewater, and photocatalytic reactor designs and their operating parameters as well as the latest development of photocatalyst incorporated membrane.

Maintenance of mitochondrial DNA copy number and expression are essential for preservation of mitochondrial function and cell growth.

To examine whether a reduction in the mtDNA level will compromise mitochondrial biogenesis and mitochondrial function, we created a cell model with depleted mtDNA. Stable transfection of small interfering (si)RNA of mitochondrial transcription factor A (Tfam) was used to interfere with Tfam gene expression. Selected stable clones showed 60-95% reduction in Tfam gene expression and 50-90% reduction in cytochrome b (Cyt b) gene expression. Tfam gene knockdown clones also showed decreased mtDNA-encoded cytochrome c oxidase subunit I (COX I) protein expression. However, no significant differences in protein expression were observed in nuclear DNA (nDNA)-encoded mitochondrial respiratory enzyme subunits. The cell morphology changed from a rhombus-like to a spindle-like form as determined in clones with decreased expressions of Tfam, mtRNA, and mitochondrial proteins. The mitochondrial respiratory enzyme activities and ATP production in such clones were significantly lower. The proportions of mtDNA mutations including 8-hydroxy-2'-deoxyguanosine (8-OHdG), a 4,977-bp deletion, and a 3,243-point mutation were also examined in these clones. No obvious increase in mtDNA mutations was observed in mitochondrial dysfunctional cell clones. The mitochondrial respiratory activity and ATP production ability recovered in cells with increased mtDNA levels after removal of the specific siRNA treatment. These experimental results provide direct evidence to substantiate that downregulation of mtDNA copy number and expression may compromise mitochondrial function and subsequent cell growth and morphology.

The role of type III secretion system and lens material on adhesion of Pseudomonas aeruginosa to contact lenses.

PURPOSE: To determine the distribution of invasive and cytotoxic genotypes among ocular isolates of P. aeruginosa and investigate the influence of the type III secretion system (T3SS) on adhesion to conventional, cosmetic, and silicone hydrogel contact lenses (CL). METHODS: Clinical isolates from 2001 to 2010 were analyzed by multiplex PCR for exoS, exoU, and exoT genes. Bacterial adhesion to etafilcon, nelfilcon (gray colored), balafilcon, and galyfilcon CL with or without artificial tear fluid (ATF) incubation were compared. Surface characteristics were determined with scanning electron microscopy (SEM). RESULTS: Among 87 total isolates, 64 strains were from microbial keratitis cases. CL-related microbial keratitis (CLMK) isolates were mostly of the cytotoxic genotype (expressing exoU) (P = 0.002). No significant differences were found in bacterial adhesion to all types of CL between the genotypes under T3SS-inducing conditions. A trend for least bacterial adhesion of galyfilcon compared to the other CL was noted for both genotypes. Needle complex pscC mutants adhered less to all materials than the wild type (P < 0.05), indicating a role of the T3SS in contact lens adhesion. ATF-incubated CL had significantly more bacterial adhesion (P < 0.05). SEM showed most of the bacteria adhering on CL surfaces. CONCLUSIONS: CLMK isolates were mostly of cytotoxic genotype. Different genotypes did not significantly differ in its adhesion to various CL. T3SS and other adhesins are involved in bacteria-contact lens adhesion through complex interactions. Contact lens materials may also play an important role in the adherence of both genotypes of P. aeruginosa.

The role of protein tyrosine phosphorylation in the cell-cell interactions, junctional permeability and cell cycle control in post-confluent bovine corneal endothelial cells.

Cell-cell interaction, junctional permeability and contact inhibition are important mechanisms that allow corneal endothelial cells to maintain stable corneal hydration status and also keep these cells in non-proliferative status. Protein tyrosine phosphatases (PTPs) are well known to play an important role in regulating cell-cell contacts, growth and differentiation. Inhibition of PTPs activity by a general PTP inhibitor has been proved to trigger post-confluent rat corneal endothelial cells to reenter cell cycles. In this study, we aimed to evaluate whether protein tyrosine phosphorylation is involved in cell-cell interactions, junctional permeability and cell cycle control in post-confluent, contact inhibited bovine corneal endothelial cells. Confluent cultures of bovine corneal endothelial cells were treated with different concentrations of general phosphatase inhibitor, sodium orthovanadate (vanadate) for several different durations. Protein tyrosine phosphorylation was confirmed by Western blot analysis. Immunocytochemistry was used to evaluate the effect of vanadate on adherens-type junctional proteins by staining of p120, N-cadherin and alpha-catenin. Paracelluar permeability was evaluated by transepithelial electric resistance. The effect of vanadate on cell cycle progression was confirmed by immunostaining of Ki67. Western blot analysis was used to evaluate the expression level of cell-cycle-associated proteins, including PCNA, cyclin D1, cyclin E and cyclin A. Time-dependent effects of vanadate on protein tyrosine phosphorylation were confirmed by Western blot analysis. ICC demonstrated the effect of vanadate on the disruption of p120, N-cadherin and alpha-catenin. Time- and dose-effects of vanadate on the severity of p120 disruption were also found. TER demonstrated the time- and dose-effect of vanadte on paracellular permeability. Although cell-cell junctions can be broken through by vanadate, no significant increase of Ki67 positive cells was found among the control group and all groups with different concentrations/durations of vanadate treatment. Western blot also showed no change of PCNA, cyclin D1, cyclin E and cyclin A after treatment with vanadate. In conclusion, protein tyrosine phosphatase inhibition can induce time-dependent release of cell-cell contacts and increase transepithelial permeability in post-confluent cultures of bovine corneal endothelial cells. However, such phenomenon is not enough to promoted cell cycle progression as seen in rat corneal endothelial cells.