Spinal arachnoiditis leading to recurrent reversible myelopathy: A case report.

Context: A patient followed in the outpatient spinal cord injury support clinic at a VA Medical Center with a prior remote history of a gunshot wound to the back and multiple prior myelograms presented with a recurrent waxing and waning weakness of the left lower extremity and intermittent incontinence of bowel and bladder.Findings: During the evaluation, the patient experienced an immediate albeit temporary improvement in symptoms after a diagnostic lumbar puncture performed for CT myelogram. The symptoms of myelopathy reoccurred several weeks, but then the patient had a similar experience with rapid improvement in symptoms after an accidental fall down a flight of steps. Subsequently, the foot weakness and incontinence returned one week later. The patient ultimately developed permanent improvement in signs and symptoms after surgical intervention which included intradural lysis of adhesions, incision of the arachnoid membrane and resection of a cystic lesion.Clinical relevance: Patients who experience unexpected, albeit transient improvement in myelopathic symptoms who are known or suspected to have arachnoiditis should be evaluated for surgically remediable lesions. Remediation of these lesions can potentially improve long term outcome.

Reviewing imaging modalities for the assessment of plaque erosion.

Plaque rupture followed by intracoronary thrombus formation is recognized as the most common pathophysiological mechanism in acute coronary syndromes (ACS). The second most common underlying substrate for ACS is plaque erosion whose hallmark is thrombus formation without cap disruption. Invasive and non-invasive methods have emerged as a promising tool for evaluation of plaque features that either predict or detect plaque erosion. Optical coherence tomography (OCT), high-definition intravascular ultrasound (IVUS), near-infrared spectroscopy (NIRS), and near-infrared autofluorescence (NIRF) have been used to study plaque erosion. The detection of plaque erosion in the clinical setting, mainly facilitated by OCT, has shed light upon the complex pathophysiology underlying ACS not related to plaque rupture. Coronary computed tomography angiography (CCTA), which is to date the most commonly used non-invasive technique for coronary plaque evaluation, may also have a role in the evaluation of patients predisposed to erosion. Also, computational models enabling quantification of endothelial shear stress may pave the way to new research in coronary plaque pathophysiology. This review focuses on the recent imaging techniques for the evaluation of plaque erosion including invasive and non-invasive assessment.

Focal arm weakness following intradetrusor botulinum toxin administration in spinal cord injury: Report of two cases.

Context: Outpatient Spinal Cord Injury follow-up practice Findings: We present two cases of individuals with tetraplegia who experienced proximal arm weakness temporally related to the administration of intradetrusor onabotulinumtoxinA without other systemic effects. This arm weakness lasted approximately three months in both cases, whereas the effect of the toxin on the bladder lasted for over six months. In one of the cases, the pattern of proximal arm weakness after intravesicular botulinum toxin injection recurred after repeat injection. Conclusion: These cases represent a previously unreported phenomenon of proximal focal weakness associated with the use of intradetrusor chemodenervation. Possible mechanisms for these cases are discussed.

Retrospective use of whole genome sequencing to better understand an outbreak of Salmonella enterica serovar Mbandaka in New South Wales, Australia

Introduction@#Salmonella enterica serovar Mbandaka is an infrequent cause of salmonellosis in New South Wales (NSW) with an average of 17 cases reported annually. This study examined the added value of whole genome sequencing (WGS) for investigating a non-point source outbreak of Salmonella ser. Mbandaka with limited geographical spread.@*Methods@#In February 2016, an increase in Salmonella ser. Mbandaka was noted in New South Wales, and an investigation was initiated. A WGS study was conducted three months after the initial investigation, analysing the outbreak Salmonella ser. Mbandaka isolates along with 17 human and non-human reference strains from 2010 to 2015.@*Results@#WGS analysis distinguished the original outbreak cases (n = 29) into two main clusters: Cluster A (n = 11) and Cluster B (n = 6); there were also 12 sporadic cases. Reanalysis of food consumption histories of cases by WGS cluster provided additional specificity when assessing associations. Discussion: WGS has been widely acknowledged as a promising high-resolution typing tool for enteric pathogens. This study was one of the first to apply WGS to a geographically limited cluster of salmonellosis in Australia. WGS clearly distinguished the outbreak cases into distinct clusters, demonstrating its potential value for use in real time to support non-point source foodborne disease outbreaks of limited geographical spread.

In Vivo and In Vitro Protein-Peptidoglycan Interactions.

Bacteria have developed a number of trans-envelope systems to transport molecules or assemble organelles across bacterial envelopes. However, bacterial envelopes contain a rigid netlike peptidoglycan structure that protects cells from osmotic lysis. Trans-envelope systems thus must interact with the peptidoglycan barrier to generate gaps or anchor structures to the peptidoglycan scaffold. Here we describe methods to use in vivo cross-linking and in vitro co-sedimentation to study protein-peptidoglycan interactions in Gram-negative bacteria. In particular, we address important considerations to ensure the specificity of the interactions in question.

Assembly of the type II secretion system.

The type II secretion system is utilized by many Gram-negative bacteria to export folded proteins to the surface and/or the extracellular environment of the cell. Although the function of the system is to move proteins from the periplasm to the outside of the cell, it is a large trans-envelope structure composed of more than a dozen different proteins present in multiple copies, including peripheral, integral inner membrane and integral outer membrane proteins plus a pseudopilus stretching between them. The establishment of this structure as an integral component of the entire envelope including the peptidoglycan layer between the two membranes requires assembly. Many of the participants and processes involved in this assembly have now been established, while other aspects remain to be discovered or more fully understood.

The solution structure of the C-terminal domain of TonB and interaction studies with TonB box peptides.

The TonB protein transduces energy from the proton gradient across the cytoplasmic membrane of Gram-negative bacteria to TonB-dependent outer membrane receptors. It is a critically important protein in iron uptake, and deletion of this protein is known to decrease virulence of bacteria in animal models. This system has been used for Trojan horse antibiotic delivery. Here, we describe the high-resolution solution structure of Escherichia coli TonB residues 103-239 (TonB-CTD). TonB-CTD is monomeric with an unstructured N terminus (103-151) and a well structured C terminus (152-239). The structure contains a four-stranded antiparallel beta-sheet packed against two alpha-helices and an extended strand in a configuration homologous to the C-terminal domain of the TolA protein. Chemical shift perturbations to the TonB-CTD (1)H-(15)N HSCQ spectrum titrated with TonB box peptides modeled from the E.coli FhuA, FepA and BtuB proteins were all equivalent, indicating that all three peptides bind to the same region of TonB. Isothermal titration calorimetry measurements demonstrate that TonB-CTD interacts with the FhuA-derived peptide with a K(D)=36(+/-7) microM. On the basis of chemical shift data, the position of Gln160, and comparison to the TolA gp3 N1 complex crystal structure, we propose that the TonB box binds to TonB-CTD along the beta3-strand.