Development of chitosan-vancomycin antimicrobial coatings on titanium implants

Techniques for titanium surface modification have been studied for applications in orthopedic implants specifically for local drug delivery. The extensive research in surface modification is driving the development of devices that integrate infection prevention, osseointegration, and functionality in a structural role. In this study, vancomycin was applied to modified titanium surfaces to determine the effect of surface morphology on drug loading and release profiles. The antimicrobial effectiveness of the released vancomycin was evaluated and found to have a similar effect as the standard vancomycin. The engineered surfaces included sandblasted, sandblasted acid etched, electrochemically etched, and sandblasted electrochemically etched. The antibiotic release was observed to be independent of the measured surface parameters of the engineered surfaces. The development of an implantable device in which the surface morphology can be tailored for an application with no effect on the total drug released would be beneficial to more precisely control the biological response while maintaining local drug delivery for infection prevention.

Recurrence patterns and prognosis of endometrial stromal sarcoma and the potential of tyrosine kinase-inhibiting therapy

OBJECTIVE

Endometrial stromal sarcoma (ESS) is a rare uterine malignancy. The current treatment approaches yield unsatisfactory results, and potential therapeutic targets need exploration.

METHODS

We reviewed the electronic medical records of 74 patients with low-grade ESS who had been evaluated at the University of Texas MD Anderson Cancer Center between 1995 and 2006. Using immunohistochemistry, we tested the expression of targets in paraffin-embedded tissue samples taken from 13 of the patients.

RESULTS

Forty-seven patients (64%) had a recurrence, and 16 (22%) had died of their disease at last follow-up. The 10-year progression-free survival (PFS) rate was 43% (median PFS duration, 108months), and the overall survival (OS) rate was 85% (median OS, 288months). Patients who received hormonal therapy had an overall response rate of 27%; another 53% had stable disease, with a median time to progression of 24months. No complete response or partial response was observed among patients who received radiotherapy or chemotherapy. In the paraffin-embedded specimens we tested, c-abl was expressed universally. Expression of PDGF-α, PDGF-β, VEGF, and c-Kit was detected in 33%, 36%, 54%, and 8%, of specimens, respectively. EGFR and HER-2 were not detectable in any specimens.

CONCLUSIONS

Our study suggests that ESS is a hormone-dependent malignancy, with hormonal therapy having activity in recurrent disease. Targeted therapy, specifically targeting c-abl may be a potential treatment for this disease.

'Lewisham scoring system' to facilitate the clinical diagnosis of empyema

INTRODUCTION

Patients with empyema of gall bladder have a higher mortality rate. We hypothesised a scoring system, which we call the Lewisham Score, to predict the development and diagnosis of empyema.

MATERIAL AND METHODS

Patient with histologically proven acute cholecystitis who underwent operation over a five year period (2004-2009) were selected and a retrospective cohort analysis of those who developed empyema vs. simple acute cholecystitis was performed. Various parameters and the Lewisham score were compared.

RESULTS

Patients with empyema were elderly females with a higher C-reactive protein and had a higher Lewisham Score of > 5 and those with simple cholecystitis had a lower Lewisham score (< 4) and lower C-reactive protein.

DISCUSSION

Patients with proven acute cholecystitis and a Lewisham score > 5 should undergo cholecystectomy at the same admission.

Genome-wide analysis of cyclins in maize (Zea mays)

Cyclins are primary regulators of the activity of cyclin-dependent kinases and play crucial roles in cell cycle progression in eukaryotes. Although extensive studies have revealed the roles of some cyclins and underlying mechanisms in plants, relatively few cyclins have been functionally analyzed in maize. We identified 59 cyclins in the maize genome, distributed on 10 chromosomes; these were grouped into six types by phylogenetic analysis. The cyclin genes in the maize genome went through numerous tandem gene duplications on five chromosomes. However, no segmental duplications, which occur in rice, were found on maize chromosomes. This information allows us to assess the position of plant cyclin genes in terms of evolution and classification, which will be useful for functional studies of maize cyclins.

Antitumour response of a double mutant of staphylococcal enterotoxin C2 with the decreased affinity for MHC class II molecule

Staphylococcal enterotoxin C2 (SEC2) is one of the most potent known activators of human T lymphocytes, and recombinant SEC2 shows promising clinical values, but SEC2 can cause food poisoning and toxic shock syndrome in vivo. In this study, site-directed mutagenesis has been used to introduce alanine substitutions at Phe144 and Leu45 in the molecule. The mutant genes were cloned and expressed, and the corresponding proteins were purified by nickel agarose affinity chromatography. We found that the SEC2 mutant proteins could stimulate the proliferation of human peripheral blood lymphocytes and inhibit the growth of tumour cells as native SEC2. Furthermore, flow cytometry assay showed that mSEC2(F44A, L45A) drastically reduced the ability of the toxin to bind to MHC class II. Physiological parameters revealed that mSEC2(F44A, L45A) reduced significantly rat temperature compared with native SEC2 in vivo. Our results clearly suggest that this genetically modified SEC2 protein is less toxic and justifies its further development as a new, safer antitumour superantigen to prevent SEC2 intoxication.

Infrared light induced patterning of proteins on ppNIPAM thermoresponsive thin films: a "protein laser printer"

Protein micropatterns have applications in fundamental life sciences and clinical medicine. In this work, we present a new technique to create 2-D protein micropatterns by local activation of a thin film of thermoresponsive plasma-deposited poly(N-isopropylacrylamide) (ppNIPAM) using a computer-controlled infrared laser beam. While the whole substrate is exposed to the protein solution, protein deposition happens only at laser-activated locations. A few seconds of laser exposure is all that is required to form a pattern with resolution in the single micrometre range. Successful ligand binding after protein deposition indicates that protein function remains intact after laser-induced adsorption onto ppNIPAM. This rapid, simple technique advances currently available strategies for protein patterning by its potential to pattern proteins in an enclosed environment or onto a 3-D scaffold.

Effects of adenoviral-mediated coexpression of bone morphogenetic protein-7 and insulin-like growth factor-1 on human periodontal ligament cells

BACKGROUND AND OBJECTIVE

Bone morphogenetic protein-7 (BMP-7) and insulin-like growth factor-1 (IGF-1) are important in periodontal reconstruction. However, their synergistic effect in periodontal regeneration by gene delivery has not been reported. In this study, gene delivery of these two growth factors to human periodontal ligament cells (hPDLCs) was examined for its effects on cell proliferation and differentiation.

MATERIAL AND METHODS

Recombinant adenoviruses containing both human BMP-7 and IGF-1 cDNA created by introducing the internal ribosome entry site (IRES) sequence were used to transfer the genes into hPDLCs. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and cell cycle analysis were used to observe their effects on cell proliferation, while alkaline phosphatase activity measurement, RT-PCR and in vivo tests were conducted to investigate their effects on cell differentiation.

RESULTS

The proliferation of hPDLCs transduced by adenoviruses coexpressing BMP-7 and IGF-1 was suppressed while their differentiation ability was enhanced. There was a synergism of BMP-7 and IGF-1 in up-regulating alkaline phosphatase activity and mRNA levels of collagen type I and Runx2. Implantation in vivo with scaffolds illustrated that the transduced cells exhibited osteogenic differentiation and formed bone-like structures.

CONCLUSION

The combined delivery of BMP-7 and IGF-1 genes using an IRES-based strategy synergistically enhanced differentiation of hPDLCs. It is suggested that this could be a new potential method in gene therapy for periodontal reconstruction.

AKT1 polymorphisms are associated with tuberculosis in the Chinese population

AKT1, a serine/threonine kinase, plays a critical role in the controlling of intracellular growth of Mycobacterium tuberculosis. In this study, we investigated whether polymorphisms in AKT1 affect susceptibility to tuberculosis (TB). Two single nucleotide polymorphisms of AKT1, IVS3+18C>T and +726G>A were genotyped in Chinese patients with pulmonary TB by polymerase chain reaction-restriction fragment length polymorphism. Patients with pulmonary TB had significantly lower IVS3+18 C/C genotype and higher C/T genotype compared with age-, gender- and ethnically matched controls (P < 0.05). The T-A haplotype frequency was significantly higher in patients than in controls (P < 0.05). In conclusion, our result indicates that AKT1 polymorphisms are associated with susceptibility to pulmonary TB.

Rapid domain wall motion in permalloy nanowires excited by a spin-polarized current applied perpendicular to the nanowire

We study domain wall dynamics in Permalloy nanowires excited by alternating spin-polarized current applied perpendicular to the nanowire. Spin torque ferromagnetic resonance measurements reveal that domain wall oscillations at a pinning site in the nanowire can be excited with velocities as high as 800 m/s at current densities below 10{7} A/cm{2}.

Overexpression of type-A rice response regulators, OsRR3 and OsRR5, results in lower sensitivity to cytokinins

Response regulators are part of a two-component regulatory system. The type-A Arabidopsis response regulators act as negative regulators. To understand the function of type-A response regulators in the model monocot plant, rice (Japonica cultivar-group: Zhonghua11), we overexpressed two type-A OsRR genes, OsRR3 and OsRR5 (pACT1:OsRR3 and pACT1:OsRR5). We hoped to gain insight into their molecular function in cytokinin-signaling pathways. Both OsRR3 and OsRR5 overexpressors had longer roots and more lateral roots compared with Zhonghua11, when treated with exogenous cytokinin. Using callus formation and chlorophyll content assays, we found that Zhonghua11 was more sensitive to cytokinin compared with other cultivars of rice, expressing high transcript levels of OsRR3 and OsRR5. The expression of most type-A OsRR genes was repressed by OsRR3 and OsRR5 overexpression. However, semi-quantitative RT-PCR showed that three type-A OsRR genes showed increased expression. Our results suggest that both OsRR3 and OsRR5 mainly act as negative regulators of cytokinin signaling, as indicated by the reduced sensitivity of OsRR3 and OsRR5 overexpressors to exogenous cytokinins.

What is the benefit of bevacizumab combined with chemotherapy in patients with recurrent ovarian, fallopian tube or primary peritoneal malignancies?

The aim of this retrospective analysis was to investigate the efficacy and adverse effects of the monoclonal antivascular endothelial growth factor antibody bevacizumab (Avastin(R)) combined with chemotherapeutic agents in non-protocol patients with recurrent ovarian, fallopian tube, or primary peritoneal malignancies. Using our databases, we identified patients treated with bevacizumab combination therapy since June 2005. Responses were evaluated with Response evaluation Criteria in Solid tumors and serum CA125 Rustin criteria. Toxicity was assessed according to the Common toxicity Criteria (CTC) v.3.0. Data from 64 patients were included. The median patient age was 58 years, and they had undergone a median of 4.5 (range, 1-10) prior cytotoxic chemotherapy regimens. The median length of follow-up was 8 months (range, 2-29). The most commonly used combinations were bevacizumab plus taxanes (26.6%) and plus cyclophosphamide (26.6%). A median of 4 cycles of therapy with a median bevacizumab dose of 3,600 mg (range, 500-18,240) were administered. An overall response rate of 21.3% was observed in 13 patients with partial response, and another 42.6% of patients had stable disease. Among the patients with elevated pretreatment serum CA125 concentration, an overall response rate of 46.3% (25/54) was observed according to modification of the Rustin criteria. Fifteen (23.4%) patients had grades 3 or 4 adverse events. Gastrointestinal perforations occurred in 2 (3.1%) patients. Seventeen (26.6%) patients had improved performance status scores. Bevacizumab combined with chemotherapy showed promising clinical benefits, with significant response of serum CA125 concentration and moderate adverse effects.

A novel allele, HLA-A*110203, was identified in a Chinese individual

This allele is characterized by a nucleotide substitution (C>T) in exon 4 at position nt 672, codon 200 (ACC>ACT), no coding change.

A frame shift due to a two-nucleotide deletion results in an HLA-B null allele, B*9549N

This report describes the identification of a new human leukocyte antigen (HLA) class I null allele, B*9549N, resulting from a premature stop codon in exon 3.

A novel HLA-B*37 allele, B*370105, was identified in a Chinese Han individual

We report here the sequence of a novel human leukocyte antigen B*37 allele, B*370105, which is identical to B*370101 except for a single nucleotide substitution in exon 3 at nucleotide 558 where C>A, codon 162 GGC>GGA, no coding change.

Resonant nonlinear damping of quantized spin waves in ferromagnetic nanowires: a spin torque ferromagnetic resonance study

We use spin torque ferromagnetic resonance to measure the spectral properties of dipole-exchange spin waves in Permalloy nanowires. Our measurements reveal that geometric confinement has a profound effect on the damping of spin waves in the nanowire geometry. The damping parameter of the lowest-energy quantized spin-wave mode depends on applied magnetic field in a resonant way and exhibits a maximum at a field that increases with decreasing nanowire width. This enhancement of damping originates from a nonlinear resonant three-magnon confluence process allowed at a particular bias field value determined by quantization of the spin-wave spectrum in the nanowire geometry.

Origin of the inverse spin switch effect in superconducting spin valves

Known as the spin switch effect (SSE), the resistance of a ferromagnet/superconductor/ferromagnet (F/S/F) spin valve near its superconducting transition temperature T c is different for parallel (R P) and antiparallel (R AP) configurations of the F layers. Here, we report the observation of the coexistence of the standard (RP>RAP) and inverse (RP<RAP) SSE in Ni81Fe19/Nb/Ni81Fe19/Ir25Mn75 spin valves. Our measurements reveal that the inverse SSE arises from a dissipative flow of vortices induced by stray magnetic fields from Néel domain-wall pairs in the F layers.