Disruption of Biofilm by Bacteriophages in Clinically Relevant Settings.

INTRODUCTION: Antibiotic-resistant bacteria are a growing threat to civilian and military health today. Although infections were once easily treatable by antibiotics and wound cleaning, the frequent mutation of bacteria has created strains impermeable to antibiotics and physical attack. Bacteria further their pathogenicity because of their ability to form biofilms on wounds, medical devices, and implant surfaces. Methods for treating biofilms in clinical settings are limited, and when formed by antibiotic-resistant bacteria, can generate chronic infections that are recalcitrant to available therapies. Bacteriophages are natural viral predators of bacteria, and their ability to rapidly destroy their host has led to increased attention in potential phage therapy applications. MATERIALS AND METHODS: The present article sought to address a knowledge gap in the available literature pertaining to the usage of bacteriophage in clinically relevant settings and the resolution of infections particular to military concerns. PRISMA guidelines were followed for a systematic review of available literature that met the criteria for analysis and inclusion. The research completed for this review article originated from the U.S. Military Academy's library "Scout" search engine, which complies results from 254 available databases (including PubMed, Google Scholar, and SciFinder). The search criteria included original studies that employed bacteriophage use against biofilms, as well as successful phage therapy strategies for combating chronic bacterial infections. We specifically explored the use of bacteriophage against antibiotic- and treatment-resistant bacteria. RESULTS: A total of 80 studies were identified that met the inclusion criteria following PRISMA guidelines. The application of bacteriophage has been demonstrated to robustly disrupt biofilm growth in wounds and on implant surfaces. When traditional therapies have failed to disrupt biofilms and chronic infections, a combination of these treatments with phage has proven to be effective, often leading to complete wound healing without reinfection. CONCLUSIONS: This review article examines the available literature where bacteriophages have been utilized to treat biofilms in clinically relevant settings. Specific attention is paid to biofilms on implant medical devices, biofilms formed on wounds, and clinical outcomes, where phage treatment has been efficacious. In addition to the clinical benefit of phage therapies, the military relevance and treatment of combat-related infections is also examined. Phages offer the ability to expand available treatment options in austere environments with relatively low cost and effort, allowing the impacted warfighter to return to duty quicker and healthier.

Intussusception after Routine Colonoscopy: A Rare Complication.

We present a 31-year-old woman who developed ascending colon intussusception several hours after a routine colonoscopy where random mucosal biopsies were obtained. She underwent an ileocolic resection, and pathology did not show an etiology for the intussusception. Colonic intussusception occuring without pathology and after minimal intervention is rare.

Update in procedural therapy for GERD--magnetic sphincter augmentation, endoscopic transoral incisionless fundoplication vs laparoscopic Nissen fundoplication.

Gastroesophageal reflux disease (GERD) is a common and progressive condition manifested by heartburn or regurgitation. Though Nissen fundoplication has been and remains the gold standard for procedural therapy for GERD, two newer interventions have gained popularity: magnetic sphincter augmentation (MSA), which entails the placement of a self expanding magnetic ring around the gastroesophageal (GE) junction, and transoral incisionless fundoplication (TIF), an endoscopic approach that creates a neogastroesophageal valve near the fundus. Collective data gathered from four studies published within the past year suggest that the three modalities share comparable effectiveness in pH monitoring and patient satisfaction, TIF may have a lower proton pump inhibitor cessation rate, and Nissen fundoplication required longer recovery time and had a more serious adverse effects profile. Large, prospective, randomized controlled studies are needed to reliably compare the three procedures.

Transient oligomerization of the SARS-CoV N protein--implication for virus ribonucleoprotein packaging.

The nucleocapsid (N) phosphoprotein of the severe acute respiratory syndrome coronavirus (SARS-CoV) packages the viral genome into a helical ribonucleocapsid and plays a fundamental role during viral self-assembly. The N protein consists of two structural domains interspersed between intrinsically disordered regions and dimerizes through the C-terminal structural domain (CTD). A key activity of the protein is the ability to oligomerize during capsid formation by utilizing the dimer as a building block, but the structural and mechanistic bases of this activity are not well understood. By disulfide trapping technique we measured the amount of transient oligomers of N protein mutants with strategically located cysteine residues and showed that CTD acts as a primary transient oligomerization domain in solution. The data is consistent with the helical oligomer packing model of N protein observed in crystal. A systematic study of the oligomerization behavior revealed that altering the intermolecular electrostatic repulsion through changes in solution salt concentration or phosphorylation-mimicking mutations affects oligomerization propensity. We propose a biophysical mechanism where electrostatic repulsion acts as a switch to regulate N protein oligomerization.

T2 magnetic resonance enables nanoparticle-mediated rapid detection of candidemia in whole blood.

Candida spp. cause both local and disseminated infections in immunocompromised patients. Bloodstream infections of Candida spp., known as "candidemia," are associated with a high mortality rate (40%), which is mainly attributed to the long diagnostic time required by blood culture. We introduce a diagnostic platform based on T2 magnetic resonance (T2MR), which is capable of sensitive and rapid detection of fungal targets in whole blood. In our approach, blood-compatible polymerase chain reaction is followed by hybridization of the amplified pathogen DNA to capture probe-decorated nanoparticles. Hybridization yields nanoparticle microclusters that cause large changes in the sample's T2MR signal. With this T2MR-based method, Candida spp. can be detected directly in whole blood, thus eliminating the need for analyte purification. Using a small, portable T2MR detection device, we were able to rapidly, accurately, and reproducibly detect five Candida species within human whole blood with a limit of detection of 1 colony-forming unit/ml and a time to result of <3 hours. Spiked blood samples showed 98% positive agreement and 100% negative agreement between T2MR and blood culture. Additionally, performance of the assay was evaluated on 21 blinded clinical specimens collected serially. This study shows that the nanoparticle- and T2MR-based detection method is rapid and amenable to automation and offers clinicians the opportunity to detect and identify multiple human pathogens within hours of sample collection.

Genomewide microRNA down-regulation as a negative feedback mechanism in the early phases of liver regeneration.

UNLABELLED: The liver is one of the few organs that have the capacity to regenerate in response to injury. We carried out genomewide microRNA (miRNA) microarray studies during liver regeneration in rats after 70% partial hepatectomy (PH) at early and mid time points to more thoroughly understand their role. At 3, 12, and 18 hours post-PH ∼40% of the miRNAs tested were up-regulated. Conversely, at 24 hours post-PH, ∼70% of miRNAs were down-regulated. Furthermore, we established that the genomewide down-regulation of miRNA expression at 24 hours was also correlated with decreased expression of genes, such as Rnasen, Dgcr8, Dicer, Tarbp2, and Prkra, associated with miRNA biogenesis. To determine whether a potential negative feedback loop between miRNAs and their regulatory genes exists, 11 candidate miRNAs predicted to target the above-mentioned genes were examined and found to be up-regulated at 3 hours post-PH. Using reporter and functional assays, we determined that expression of these miRNA-processing genes could be regulated by a subset of miRNAs and that some miRNAs could target multiple miRNA biogenesis genes simultaneously. We also demonstrated that overexpression of these miRNAs inhibited cell proliferation and modulated cell cycle in both Huh-7 human hepatoma cells and primary rat hepatocytes. From these observations, we postulated that selective up-regulation of miRNAs in the early phase after PH was involved in the priming and commitment to liver regeneration, whereas the subsequent genomewide down-regulation of miRNAs was required for efficient recovery of liver cell mass. CONCLUSION: Our data suggest that miRNA changes are regulated by negative feedback loops between miRNAs and their regulatory genes that may play an important role in the steady-state regulation of liver regeneration.

Co dimers on hexagonal carbon rings proposed as subnanometer magnetic storage bits.

It is demonstrated by means of density functional and ab initio quantum chemical calculations, that transition-metal-carbon systems have the potential to enhance the presently available area density of magnetic recording by 3 orders of magnitude. As a model system, Co2 benzene with a diameter of 0.5 nm is investigated. It shows a magnetic anisotropy of the order of 0.1 eV per molecule, large enough to store permanently 1 bit of information at temperatures considerably larger than 4 K. A similar performance can be expected, if cobalt dimers are deposited on graphene or on graphite.

Prox1 promotes lineage-specific expression of fibroblast growth factor (FGF) receptor-3 in lymphatic endothelium: a role for FGF signaling in lymphangiogenesis.

Fibroblast growth factors play important roles in angiogenesis, but their functions in lymphangiogenesis remain poorly understood. The homeodomain transcription factor Prox1 is essential for development of the lymphatic system by specifying lymphatic endothelial cell (LEC) fate. Here, we identify fibroblast growth factor (FGF) receptor (FGFR)-3 as a novel Prox1 target gene. Ectopic overexpression of Prox1 in blood vascular endothelial cells up-regulates FGFR-3. Prox1 induces the expression of the IIIc isoform, which we also found to be the major isoform of FGFR-3 expressed in LECs. This transcriptional activation is mediated by a direct binding of Prox1 to newly identified Prox1-response elements in the FGFR-3 promoter. Consistently, FGFR-3 is up-regulated in Prox1-positive newly formed lymphatic vessels during embryogenesis and its lymphatic-specific expression is maintained throughout development. We also found that FGF-1 and FGF-2 promote proliferation, migration, and survival of cultured LECs without involvement of vascular endothelial cell growth factor receptor-3. We show that FGF-2 binds to low- and high-affinity receptors on LECs and is efficiently internalized and processed. Moreover, functional inhibition of FGFR-3 using small interfering RNA represses LEC proliferation. Together, these results indicate that FGFR-3 is an initial target of Prox1 during the lymphatic cell fate specification and that FGF signaling may play an important role in lymphatic vessel development.

Design and synthesis of a new binucleating ligand via cobalt-promoted C-N bond fusion reaction. Ligand isolation and its coordination to nickel, palladium, and platinum.

A new polydentate bridging ligand, NH(4)C(5)N=NC(6)H(4)N(H)C(5)H(4)N (HL(2)), is synthesized by the cobalt-mediated phenyl ring amination of coordinated NH(4)C(5)N=NC(6)H(5). The green cobalt complex intermediate [Co(L(2))(2)](ClO(4)), [1](ClO(4)), and the free ligand HL(2) were isolated and characterized. The X-ray structure of [H(2)L(2)](ClO(4)) is reported. The ligand, upon deprotonation, behaves as a bridging ligand. It reacts with NiCl(2).6H(2)O and Na(2)[PdCl(4)] to produce dimetallic complexes, [Ni(2)Cl(2)(L(2))(2)], 2, and [Pd(2)(L(2))(2)](ClO(4))(2), [3](ClO(4))(2), respectively. X-ray structures of these two dimetallic complexes are reported. The structure of the dinickel complex, in particular, is unique. In this complex, the two deprotonated secondary amine nitrogens of the two [L(2)](-) ligands bind to two nickel centers simultaneously forming a planar Ni(2)N(2) arrangement. The complex [3](ClO(4))(2) is diamagnetic while the complex 2 is paramagnetic. The results of magnetic measurements on the dinickel complex in the temperature range 1.8-300 K are reported. The system can be described as a single spin S = 2 in the low-temperature range T << J/k whereas at high temperatures, T >> J/k, it behaves as two independent spins S = 1.The reaction of [L(2)](-) with K(2)[PtCl(4)], however, yielded a monometallic platinum complex, [PtCl(3)(L(2))], 5, where the pyridyl nitrogen of the aminopyridyl function remained unused. The X-ray structure of the complex 4a is reported. The bond lengths along the ligand backbones in all the complexes indicate extensive pi-delocalization. Spectral data of the complexes are reported and compared.