Thoracobifemoral bypass for infrarenal aortic occlusion caused by retroperitoneal fibrosis.

Retroperitoneal fibrosis (RPF) is an uncommon fibrotic disorder that can cause pain, ureteral obstruction, deep venous thrombosis, hydrocele, and, rarely, aortic occlusion. Herein is described a 65-year-old man with aortic occlusion from idiopathic RPF who was treated with axillobifemoral bypass grafting, which failed in the intermediate term. On representation with critical claudication, he underwent thoracobifemoral bypass grafting via a lateral retroperitoneal tunnel created through a midline, infraumbilical counterincision. He was discharged home on postoperative day 5. This illustrates the successful use of thoracic aortic inflow to treat the aortoiliac occlusive complication of RPF.

Ubiquitous selection for mecA in community-associated MRSA across diverse chemical environments.

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is threatening public health as it spreads worldwide across diverse environments. Its genetic hallmark, the mecA gene, confers resistance to many ß-lactam antibiotics. Here, we show that, in addition, mecA provides a broad selective advantage across diverse chemical environments. Competing fluorescently labelled wild-type and mecA-deleted CA-MRSA USA400 strains across ~57,000 compounds supplemented with subinhibitory levels of the ß-lactam drug cefoxitin, we find that mecA provides a widespread advantage across ß-lactam and non ß-lactam antibiotics, non-antibiotic drugs and even diverse natural and synthetic compounds. This advantage depends on the presence of cefoxitin and is strongly associated with the compounds' physicochemical properties, suggesting that it may be mediated by differential compounds permeability into the cell. Indeed, mecA protects the bacteria against increased cell-envelope permeability under subinhibitory cefoxitin treatment. Our findings suggest that CA-MRSA success might be driven by a cell-envelope mediated selective advantage across diverse chemical compounds.

Data on whole length myosin binding protein C stabilizes myosin S2 as measured by gravitational force spectroscopy.

Data presented in this article relates to the research article entitled "Whole length myosin binding protein C stabilizes myosin subfragment-2 (S2) flexibility as measured by gravitational force spectroscopy." (Singh et al., 2018) [1]. The data exhibits the purified skeletal myosin binding protein C (MyBPC) from rabbit back muscle was of slow skeletal type confirmed by chromatography and in unphosphorylated state based on its isoelectric point (pI) by chromatofocussing. The competitive enzyme linked immunosorbent assay (cELISA) data displayed the site specificity of polyclonal anti-S2 antibody to myosin S2. This polyclonal antibody binding site corresponds to a familial hypertrophic cardiomyopathy (FHC) point mutation hotspot on myosin S2 illustrated in a figure of compiled data.

Whole length myosin binding protein C stabilizes myosin S2 as measured by gravitational force spectroscopy.

The mechanical stability of the myosin subfragment-2 (S2) was tested with simulated force spectroscopy (SFS) and gravitational force spectroscopy (GFS). Experiments examined unzipping S2, since it required less force than stretching parallel to the coiled coil. Both GFS and SFS demonstrated that the force required to destabilize the light meromyosin (LMM) was greater than the force required to destabilize the coiled coil at each of three different locations along S2. GFS data also conveyed that the mechanical stability of the S2 region is independent from its association with the myosin thick filament using cofilaments of myosin tail and a single intact myosin. The C-terminal end of myosin binding protein C (MyBPC) binds to LMM and the N-terminal end can bind either S2 or actin. The force required to destabilize the myosin coiled coil molecule was 3 times greater in the presence of MyBPC than in its absence. Furthermore, the in vitro motility assay with full length slow skeletal MyBPC slowed down the actin filament sliding over myosin thick filaments. This study demonstrates that skeletal MyBPC both enhanced the mechanical stability of the S2 coiled coil and reduced the sliding velocity of actin filaments over polymerized myosin filaments.

Poor Repair of Skeletal Muscle in Aging Mice Reflects a Defect in Local, Interleukin-33-Dependent Accumulation of Regulatory T Cells.

Normal repair of skeletal muscle requires local expansion of a special population of Foxp3(+)CD4(+) regulatory T (Treg) cells. Such cells failed to accumulate in acutely injured muscle of old mice, known to undergo ineffectual repair. This defect reflected reduced recruitment of Treg cells to injured muscle, as well as less proliferation and retention therein. Interleukin-33 (IL-33) regulated muscle Treg cell homeostasis in young mice, and its administration to old mice ameliorated their deficits in Treg cell accumulation and muscle regeneration. The major IL-33-expressing cells in skeletal muscle displayed a constellation of markers diagnostic of fibro/adipogenic progenitor cells and were often associated with neural structures, including nerve fibers, nerve bundles, and muscle spindles, which are stretch-sensitive mechanoreceptors important for proprioception. IL-33(+) cells were more frequent after muscle injury and were reduced in old mice. IL-33 is well situated to relay signals between the nervous and immune systems within the muscle context.

A Hybrid Drug Limits Resistance by Evading the Action of the Multiple Antibiotic Resistance Pathway.

Hybrid drugs are a promising strategy to address the growing problem of drug resistance, but the mechanism by which they modulate the evolution of resistance is poorly understood. Integrating high-throughput resistance measurements and genomic sequencing, we compared Escherichia coli populations evolved in a hybrid antibiotic that links ciprofloxacin and neomycin B with populations evolved in combinations of the component drugs. We find that populations evolved in the hybrid gain less resistance than those evolved in an equimolar mixture of the hybrid's components, in part because the hybrid evades resistance mediated by the multiple antibiotic resistance (mar) operon. Furthermore, we find that the ciprofloxacin moiety of the hybrid inhibits bacterial growth whereas the neomycin B moiety diminishes the effectiveness of mar activation. More generally, comparing the phenotypic and genotypic paths to resistance across different drug treatments can pinpoint unique properties of new compounds that limit the emergence of resistance.

The active site protonation states of perdeuterated Toho-1 ß-lactamase determined by neutron diffraction support a role for Glu166 as the general base in acylation.

Room temperature neutron diffraction data of the fully perdeuterated Toho-1 R274N/R276N double mutant ß-lactamase in the apo form were used to visualize deuterium atoms within the active site of the enzyme. This perdeuterated neutron structure of the Toho-1 R274N/R276N reveals the clearest picture yet of the ground-state active site protonation states and the complete hydrogen-bonding network in a ß-lactamase enzyme. The ground-state active site protonation states detailed in this neutron diffraction study are consistent with previous high-resolution X-ray studies that support the role of Glu166 as the general base during the acylation reaction in the class A ß-lactamase reaction pathway.