Control of bromate and THM precursors using ozonation combined system.

OBJECTIVE: To investigate the feasibility of reducing THM precursors and controlling bromate taste and odor in drinking water taken from the Yellow River by an ozonation combined system. METHODS: The appropriate ozone dosage was determined, and then the changes of TOC, UV254 and THM formation potential (THMFP) in the combined system were evaluated. RESULTS: One mg/L ozone could effectively remove taste and odor and meet the maximum allowable bromate level in drinking water. The pre-ozonation increased THMFP, but the conventional treatment system could effectively reduce the odor. The bio-ceramic filter could partly reduce CHCl3FP, but sometimes might increase CHCl2BrFP and CHClBr2FP. The biological activated carbon (BAC) filter could effectively reduce CHCl3FP and CHCl2BrFP, but increase CHClBr2FP. Compared with other filters, the fresh activated carbon (FAC) filter performed better in reducing THMFP and even reduced CHClBr2FP. CONCLUSION: The combined system can effectively reduce taste, odor, CHCl3FP, and CHCl2BrFP and also bring bromate under control.

hTERT- and hCTLA4Ig-expressing human bone marrow-derived mesenchymal stem cells: in vitro and in vivo characterization and osteogenic differentiation.

Multipotent mesenchymal stem cells (MSCs) are commonly used as seed cells in studies of tissue engineering and regenerative medicine but their clinical application is limited, due to insufficient numbers of autogeneic MSCs, immune rejection of allogeneic MSCs and replicative senescence. We constructed two gene expression vectors for transfection of the human telomerase reverse transcriptase (hTERT) and cytotoxic T lymphocyte-associated antigen 4-Ig (CTLA4Ig) genes into human bone marrow-derived stem cells (hBMSCs). Successful transfection of both genes generated hTERT-CTLA4Ig hBMSCs that expressed both telomerase (shown by immunohistochemistry and a TRAPeze assay) and CTLA4Ig (demonstrated by immunocytochemistry and western blotting) without apparent mutual interference. Both hTERT BMSCs (92 population doublings) and hTERT-CTLA4Ig hBMSCs (60 population doublings) had an extended lifespan compared with hBMSCs (18 population doublings). Cell cycle analysis revealed that, compared with hBMSCs, a lower proportion of hTERT hBMSCs were in G0 /G1 phase but a higher proportion were in S phase; compared with hTERT hBMSCs, a higher proportion of hTERT-CTLA4Ig hBMSCs were in G0 /G1 phase, while a lower proportion were in S and G2 /M phases. hTERT-CTLA4Ig hBMSCs retained their capacity for osteogenic differentiation in vitro, shown by the detection of hydroxyapatite mineral deposition (labelled tetracycline fluorescence staining), calcareous nodules (alizarin red S staining), alkaline phosphatase (calcium-cobalt method) and osteocalcin (immunocytochemistry). Furthermore, subcutaneous transplantation of hTERT-CTLA4Ig hBMSCs in a rat xenotransplantation model resulted in the successful generation of bone-like tissue, confirmed using radiography and histological assessment. We propose that allogeneic hTERT-CTLA4Ig hBMSCs may be ideal seed cells for bone tissue engineering. Copyright © 2014 John Wiley & Sons, Ltd.

hCTLA4-gene modified human bone marrow-derived mesenchymal stem cells as allogeneic seed cells in bone tissue engineering.

Immune rejection of heterogeneic seed cells, even of low antigenicity human bone marrow derived mesenchymal stem cells (hBMMSCs), remains an obstacle for bone tissue engineering. It is still a question how to transfer the gene of human cytotoxic T lymphocyte-associated antigen 4-Ig (CTLA4-Ig), a well-known ligand for CD80/CD86, to hBMMSCs to prolong survival time while not interfering with their osteogenesis in vivo. Our data, for the first time, clearly demonstrate that CTLA4-Ig gene modified hBMMSCs could normally differentiate to osteoblasts in vitro, significantly inhibit immune response in the model of mixed lymphocyte culture, and survive until bone tissue formed in vivo. Thus, CTLA4Ig gene-modified hBMMSCs might be promising seed cells for bone tissue engineering.

Reduction of precursors of chlorination by-products in drinking water using fluidized-bed biofilm reactor at low temperature.

OBJECTIVE: To investigate the reduction of chlorination by-products (CBPs) precursors using the fluidized-bed biofilm reactor (FBBR). METHODS: Reduction of total organic carbon (TOC), ultraviolet absorbance (UV254), trihalomethane (THM) formation potential (THMFP), haloacetic acid (HAA) formation potential (HAAFP), and ammonia in FBBR were evaluated in detail. Results The reduction of TOC or UV254 was low, on average 12.6% and 4.7%, respectively, while the reduction of THMFP and HAAFP was significant. The reduction of ammonia was 30%-40% even below 3 degrees C, however, it could quickly rise to over 50% above 3degrees C. Conclusions The FBBR effectively reduces CBPs and ammonia in drinking water even at low temperature and seems to be a very promising and competitive drinking water reactor for polluted surface source waters, especially in China.

[Effect of HMME-PDT on hyperplastic scar in rabbit ear model].

OBJECTIVE: To investigate the effect of HMME-PDT (Hematoporphyrin Monomethyl Ether-Photodynamic therapy) on Hyperplastic scar in the rabbit ear. METHODS: The acute model of dermal Hyperplastic scar in the rabbit ear was established. 24 scars were randomly divided into 2 groups: the experimental group (n = 12) received HMME-PDT treatment, and the controlled group (n = 12) received no special treatment. Specimens were harvested from scars on postoperative 28 day. Scar hyper plasty and collagen fibers were observed by haematoxylin-eosin staining and Van-Gieson staining respectively. The microvessel density was calculated under microscope. RESULTS: Compared with the controlled group, HMME-PDT treatment in the experimental group reduced scar formation, decreased the microvessel density and prevented excess collagen deposition at the wound site. CONCLUSIONS: HMME-PDT may play a role in inhibiting hyperplastic scar in rabbit ear.