Reduced Staphylococcus aureus biofilm formation in the presence of chitosan-coated iron oxide nanoparticles.

Staphylococcus aureus can adhere to most foreign materials and form biofilm on the surface of medical devices. Biofilm infections are difficult to resolve. The goal of this in vitro study was to explore the use of chitosan-coated nanoparticles to prevent biofilm formation. For this purpose, S. aureus was seeded in 96-well plates to incubate with chitosan-coated iron oxide nanoparticles in order to study the efficiency of biofilm formation inhibition. The biofilm bacteria count was determined using the spread plate method; biomass formation was measured using the crystal violet staining method. Confocal laser scanning microscopy and scanning electron microscopy were used to study the biofilm formation. The results showed decreased viable bacteria numbers and biomass formation when incubated with chitosan-coated iron oxide nanoparticles at all test concentrations. Confocal laser scanning microscopy showed increased dead bacteria and thinner biofilm when incubated with nanoparticles at a concentration of 500 µg/mL. Scanning electron microscopy revealed that chitosan-coated iron oxide nanoparticles inhibited biofilm formation in polystyrene plates. Future studies should be performed to study these nanoparticles for anti-infective use.

Bevacizumab did not reduce the risk of anemia associated with chemotherapy: an up-to-date meta-analysis.

PURPOSE: The risk of anemia due to bevacizumab-based chemotherapy has not been well described, and new randomized controlled trials (RCTs) have been reported in recent years. We therefore conducted an up-to-date meta-analysis of RCTs to fully characterize the risk of anemia with bevacizumab. METHODS: We carried out an electronic search of Medline, Embase, and The Cochrane Central Register of Controlled Trials to investigate the effects of RCTs on bevacizumab treatment on cancer patients up to October 2014, and random or fixed-effect meta-analytical models were used to assess the risk ratio (RR) of anemia due to the use of bevacizumab according to the heterogeneity of included studies. RESULTS: A total of 13,173 patients were included in this analysis from 18 RCTs. Among those patients receiving bevacizumab and chemotherapy, the incidences of all-grade and high-grade (grade 3 and above) anemia were 24% (95% confidence interval (CI) 13-41%) and 4.0% (95% CI 3.0-6.0%), respectively. Bevacizumab-containing therapy did not significantly decreased the risk of developing all-grade anemia (RR 0.872, 95% CI 0.739-1.029, P = 0.104) and high-grade anemia (RR 0.850, 95% CI 0.720-1.002, P = 0.053), which is not in agreement with previous meta-analysis. On subgroup analysis, we did not find significant risk differences based on bevacizumab dosage, tumor types, and concomitant drugs. When stratified by dose level, a significantly decreased risk of high-grade anemia with bevacizumab was obtained in a lower dose level (2.5 mg/kg/week, RR 0.773, 95% CI 0.611-0.978, P = 0.031) compared to control group. CONCLUSIONS: Bevacizumab did not significantly reduce the risk of anemia with chemotherapy in cancer patients.

A novel classification to guide total hip arthroplasty for adult acetabular dysplasia.

In the field of hip arthroplasties, the secondary fixation of the implants depends directly on the quality of the primary stability. A good acetabular fit and metaphyseal filling between the prostheses and implants improve the initial stabilization, and optimize the transmission of forces to the bone. A precise knowledge of the three-dimensional acetabular or femoral shape is essential to the selection of adapted implants. A total of 63 patients diagnosed with developmental dysplasia were analyzed by three-dimensional computed tomography (3DCT), and the preoperative radiographic and 3DCT images were used to assess the acetabular/femoral deformities and variations of the hips. All joints were classified as Crowe type I, and bilateral measurements were taken for 10 patients. The acetabular abnormalities were classified according to the type of deficiency and the section angles of the acetabulum, with 26 hips (36%) classified as an anterior deficiency, 13 hips (18%) as a posterior deficiency and 34 hips (46%) as a lateral deficiency. The femoral side deformities were divided into three types according to the anteversion angle of the femur. A gradual increase in anteversion angle led to secondary rotational anomalies, and a narrowing of the canal at the isthmus. A total of 35 hips (48%) were classified as an F1 type deficiency, femur anteversion angle (FAVA) <30°; 32 hips (44%) as F2-type, 30°≤ FAVA ≤40°, with mild abnormalities of the femoral canal rotation and the diameter of the isthmus; and 6 hips (8%) as F3 type, FAVA >40°, with significant abnormalities of the femoral canal rotation and the diameter of the isthmus. This novel classification for adult acetabular dysplasia may provide a useful guide for surgery, and enable an improved selection of a suitable prosthesis.

Staphylococcus aureus supernatant induces the release of mouse ß-defensin-14 from osteoblasts via the p38 MAPK and NF-κB pathways.

Mammalian ß-defensins are small cationic peptides of approximately 2-6 kDa that have been implicated in mediating innate immune defenses against microbial infection. Previous studies have reported that mouse ß-defensin-14 (MBD­14), based on structural and functional similarities, appears to be an ortholog of human ß-defensin-3 (HBD-3). The aim of this study was to identify the signaling pathways that contribute to the expression of MBD-14 in mouse osteoblasts (OBs) upon contact with methicillin-resistant Staphylococcus aureus (S. aureus) supernatant (SAS) to provide a theoretical basis for the use of MDB-14 as a therapeutic agent in the treatment of intramedullary infection with S. aureus in vivo. The bacterial exoproducts released by S. aureus mainly include a large amount of enterotoxins. Using mouse OBs, the release and regulation of MBD-14 was evaluated by real-time polymerase chain reaction (PCR) and enzyme­linked immunosorbent assay (ELISA) following exposure to SAS. The activation of the p38 mitogen­activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK) and nuclear factor-κB (NF-κB) pathways was determined by western blot analysis. OBs treated with lipopolysaccharide (LPS) were used as the positive control. The results revealed that SAS significantly promoted the phosphorylation of p38 MAPK, NF-κB and the inhibitory subunit of NF-κBα (IκBα) in a time-dependent manner. The treatment of OBs with SB203580 (an inhibitor of p38 MAPK) and pyrrolidine dithiocarbamate (PDTC, an inhibitor of NF-κB) prior to stimulation with SAS significantly inhibited the phosphorylation and mRNA expression of p38 MAPK and NF-κB p65, simultaneously reducing the release of MBD-14. Our findings suggest that the release of MBD-14 is mediated at least in part through the activation of p38 MAPK and NF-κB in response to S. aureus­secreted bacterial exoproducts. Moreover, our data demonstrate the innate immune capacity of OBs under conditions of bacterial challenge to enhance the local expression of this MBD-14, a peptide with anti­staphylococcal activity.

Ultrasonically enhanced rifampin activity against internalized Staphylococcus aureus.

Staphylococcus aureus (S. aureus) is the principle causative agent of osteomyelitis, accounting for 80% of all human cases. S. aureus internalized in osteoblasts escapes immune response, including engulfment by phagocytes. It also escapes the action of a number of antibiotics. Ultrasound increases cell membrane permeability to a number of drugs. Following an internalization assay, we used low-frequency, low-power ultrasound combined with the antibiotic rifampin to target S. aureus internalized in human osteoblasts. Tryptic soy agar (TSA) was used to quantitate the antibacterial effect of rifampin combined with low-frequency ultrasound. A Cell Counting Kit-8 (CCK-8) assay was used to evaluate cell viability following exposure to ultrasound. Our data revealed that rifampin successfully penetrates into osteoblasts and kills internalized S. aureus in osteoblasts, while low-frequency ultrasound promotes this process. Ultrasound had a negative impact on the cell viability of osteoblasts; however, this damage was slight and reversible. Ultrasound-enhanced antibiotic efficiency to bacteria internalized in the osteoblasts may contribute to the control of chronic infection to reduce recurrence.

Biocompatibility of chitosan-coated iron oxide nanoparticles with osteoblast cells.

BACKGROUND: Bone disorders (including osteoporosis, loosening of a prosthesis, and bone infections) are of great concern to the medical community and are difficult to cure. Therapies are available to treat such diseases, but all have drawbacks and are not specifically targeted to the site of disease. Chitosan is widely used in the biomedical community, including for orthopedic applications. The aim of the present study was to coat chitosan onto iron oxide nanoparticles and to determine its effect on the proliferation and differentiation of osteoblasts. METHODS: Nanoparticles were characterized using transmission electron microscopy, dynamic light scattering, x-ray diffraction, zeta potential, and vibrating sample magnetometry. Uptake of nanoparticles by osteoblasts was studied by transmission electron microscopy and Prussian blue staining. Viability and proliferation of osteoblasts were measured in the presence of uncoated iron oxide magnetic nanoparticles or those coated with chitosan. Lactate dehydrogenase, alkaline phosphatase, total protein synthesis, and extracellular calcium deposition was studied in the presence of the nanoparticles. RESULTS: Chitosan-coated iron oxide nanoparticles enhanced osteoblast proliferation, decreased cell membrane damage, and promoted cell differentiation, as indicated by an increase in alkaline phosphatase and extracellular calcium deposition. Chitosan-coated iron oxide nanoparticles showed good compatibility with osteoblasts. CONCLUSION: Further research is necessary to optimize magnetic nanoparticles for the treatment of bone disease.

Low-dose strontium-90 irradiation is effective in preventing the recurrence of pterygia: a ten-year study.

BACKGROUND: To study the long-term effects of low-dosage strontium-90 (Sr90) irradiation on the recurrence of pterygium. METHODOLOGY/PRINCIPAL FINDINGS: One hundred twenty eyes from 104 patients with primary or recurrent pterygia were treated with surgery followed by Sr90 irradiation. In brief, starting on the sixth day after surgery, patients were treated with irradiation three times every other day at a total combined dosage of 2000 cGy to 3000 cGy. Corneal topography was used to evaluate ocular surface regularity before and after treatment. Patient follow-up was performed 2 days, 5 days, 2 weeks, 1 month, 3 months, 1 year, 5 years, and 10 years after surgery. Recurrence of pterygium was not observed in any of the patients in this study. Obvious cataract progression was observed in 6 eyes, which may be due to aging. During follow-up studies, only one eye was reported with dryness and foreign-body sensation. Significant pterygium-induced astigmatism was observed in corneal topography, which decreased after surgery. CONCLUSIONS/SIGNIFICANCE: Sr90 irradiation is effective in preventing the recurrence of primary and recurrent pterygia. We recommend delivering a total combined dosage of 2000 cGy to 3000 cGy of Sr90 irradiation administered in three batches every other day starting from the sixth day after surgery. Surgery is important in the rapid recovery of the cornea from pterygium-induced astigmatism.

[Founder effect of two families with TGFBI related Thiel-Behnke corneal dystrophy].

OBJECTIVE: To investigate the transforming growth factor beta induced (TGFBI; BIGH3) gene mutation and founder effect of two large Chinese families clinically diagnosed as Thiel-Behnke corneal dystrophy. METHODS: Fifteen members including 13 affected and 2 healthy in family A, 14 members including 6 affected and 8 healthy in family B, as well as 20 other unrelated healthy individuals were tested for TGFBI gene mutation. Haplotype analysis and clinical examination were also carried out in the two families. RESULTS: In exon 12 of the TGFBI gene, 1664G to A change was detected in all the patients, which leads to an amino acid replacement of arginine with glutamine (p.Arg555Gln). Members of the two families share some similar haplotypes. CONCLUSION: Genetic analysis is helpful in the diagnosis of corneal dystrophy. The two families may come from a same ancestor.

Potent neutralization antibody elicited in mice by SARS-associated coronavirus spike protein S1 domain / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To study the antigenicity of SARS associated coronavirus (CoV) spike S1 (12-672Aa) domain.</p><p><b>METHODS</b>BALB/c mice were immunized with a plasmid bearing codon-optimized SARS-CoV (Tor2 strain) S1 domain and then boosted with purified S1 protein; the SARS-CoV specific IgG antibody was tested by ELISA and neutralization antibody was determined by in vitro microneutralization assay.</p><p><b>RESULTS</b>S1 domain of SARS-CoV spike, which has been demonstrated harboring the receptor binding domain, successfully elicited SARS-CoV specific IgG antibody in mouse after combined immunization with DNA and purified S1 protein; the antibody elicited solely by S1 could potently neutralize SARS-CoV (HKU-39849) in vitro, 50% of 1 000 TCID50 SARS-CoV challenged cells were protected from viral infection by a 1:1499.68 dilution of mice sera immunized with S1 protein, but negative control sera showed no protection.</p><p><b>CONCLUSION</b>S1 domain of SARS-CoV spike protein, which is responsible for receptor binding, can efficiently and sufficiently induce highly potent neutralizing antibody in mice. This result suggested that S1 domain could be an effective subunit vaccines against SARS-CoV.</p>