Sonographic evaluation of peripheral nerve pathology in the emergency setting.

High-resolution sonography has a growing role in both the diagnosis and management of traumatic and atraumatic peripheral nerve pathology. Sonography not only affords a cost-effective and time-efficient approach to interrogating long segments of peripheral nerves but also possesses unique advantages in terms of its dynamic, real-time nature with few clinical contraindications and limitations. In this review, we will initially discuss imaging techniques and characteristics of normal neural sonohistology, then address specific features and pitfalls pertaining to the spectrum of post-traumatic peripheral nerve injury. Additionally, we will highlight the more common sonographic applications in the clinical work-up of patients presenting with symptoms of dynamic neural impingement and entrapment. Finally, illustrative and clinical features of the more frequently encountered peripheral neural neoplastic pathologies will be addressed.

Photorhabdus phase variants express a novel fimbrial locus, mad, essential for symbiosis.

Fimbriae are adhesive organelles known to enable pathogens to colonize animal tissue, but little is known of their function in mutualistic symbioses. Photorhabdus colonization of Heterorhabditis bacteriophora nematodes is essential for the pair's insect pathogenic lifestyle. Maternal nematodes acquire Photorhabdus symbionts as a persistent intestinal biofilm prior to transmission to infective juvenile (IJ) stage offspring developing inside the maternal body. Screening 8000 Photorhabdus mutants for defects in IJ colonization revealed that a single fimbrial locus, named mad for maternal adhesion defective, is essential. The mad genes encode a novel usher/chaperone assembled fimbria regulated by an ON/OFF invertible promoter switch. Adherent Photorhabdus cells in maternal nematode intestines had the switch ON opposite to the OFF orientation of most other cells. A ΔmadA mutant failed to adhere to maternal intestines and be transmitted to the IJs. Mad fimbriae were detected on TT01 phase ON cells but not on ΔmadA phase ON cells. Also required for transmission is madJ, predicted to encode a transcriptional activator related to GrlA. Expression of madA-K or madIJK restored the ability of madJ mutant to adhere. The Mad fimbriae were not required for insect pathogenesis, indicating the specialized function of Mad fimbriae for symbiosis.

Imaging of Neurotrauma in Acute and Chronic Settings.

Traumatic injuries of the brain and spinal cord are a significant source of mortality and long-term disability. A recent systematic study in a rat model of spinal cord injury (SCI) indicates severe, destructive, and very protracted inflammation as the key mechanism initiated by the massive injury involving the white matter. Although the severe inflammation is localized and counteracted by astrogliosis, it has a damaging effect on the blood vessels in the surrounding spinal cord, leading to persistent vasogenic edema. Evaluation of these injuries with imaging of the brain and spinal cord plays a crucial role in the acute trauma work-up, allowing clinicians to quickly identify abnormalities that require immediate medical or surgical intervention or to exclude them from the workup. Recently, anti-inflammatory agents have been shown to inhibit and accelerate the elimination of post-SCI inflammation in preclinical studies, and an exciting potential has arisen for the use of antiinflammatory drugs in clinical studies to achieve neuroprotection (i.e., inhibition of destruction caused by inflammation) and to inhibit vasogenic edema in SCI, traumatic brain injury, and stroke. In both subacute and chronic settings, imaging can guide therapy and provide important prognostic information. In this review, we discuss the imaging workup and evolving imaging findings of neurotrauma in the acute and chronic setting, including conventional and advanced imaging techniques. As neuroimaging is the primary mode of diagnostic analysis in neurotrauma, it is a critical component in future clinical trials evaluating neuroprotective therapies.

Ultrasonographic and radiographic findings of polyethylene component displacement with severe metallosis and metal-induced synovitis following total knee arthroplasty.

Aseptic loosening and wear is second to only infection as the most common cause of arthroplasty failure. Degeneration of the polyethylene and metal arthroplasty components can lead to metallosis, which can cause a combination of direct cytotoxic effects and an inflammatory response within the synovial and periarticular tissues. This can result in bone resorption and secondary arthroplasty component loosening as well as a metal containing joint effusion and metal-induced synovitis. Little literature exists as to the ultrasonographic findings of metal-induced synovitis and polyethylene component displacement. As the use of musculoskeletal ultrasound significantly increases, being aware of these findings is important. The most important ultrasonographic findings include differentiating a joint effusion from synovitis utilizing dynamic compression, identifying areas of echogenic shadowing related to metal deposition and visualizing displaced arthroplasty components. The following is a case report that demonstrates the ultrasonographic imaging findings of metallosis, metal-induced synovitis and polyethylene component displacement. We will also demonstrate the ultrasound-guided aspiration findings as well as radiographic and gross pathologic correlations.