Spatiotemporal microRNA profile in peripheral nerve regeneration: miR-138 targets vimentin and inhibits Schwann cell migration and proliferation.

While the peripheral nervous system has regenerative ability, restoration of sufficient function remains a challenge. Vimentin has been shown to be localized in axonal growth fronts and associated with nerve regeneration, including myelination, neuroplasticity, kinase signaling in nerve axoplasm, and cell migration; however, the mechanisms regulating its expression within Schwann cell (SC) remain unexplored. The aim of this study was to profile the spatial and temporal expression profile of microRNA (miRNA) in a regenerating rat sciatic nerve after transection, and explore the potential role of miR-138-5p targeting vimentin in SC proliferation and migration. A rat sciatic nerve transection model, utilizing a polyethylene nerve guide, was used to investigate miRNA expression at 7, 14, 30, 60, and 90 days during nerve regeneration. Relative levels of miRNA expression were determined using microarray analysis and subsequently validated with quantitative real-time polymerase chain reaction. In vitro assays were conducted with cultured Schwann cells transfected with miRNA mimics and assessed for migratory and proliferative potential. The top seven dysregulated miRNAs reported in this study have been implicated in cell migration elsewhere, and GO and KEGG analyses predicted activities essential to wound healing. Transfection of one of these, miRNA-138-5p, into SCs reduced cell migration and proliferation. miR-138-5p has been shown to directly target vimentin in cancer cells, and the luciferase assay performed here in rat Schwann cells confirmed it. These results detail a role of miR-138-5p in rat peripheral nerve regeneration and expand on reports of it as an important regulator in the peripheral nervous system.

Common postburn deformities and their management.

This article describes a practical, clinically based approach to classification of postburn deformities. Burn scar contractures are of either the broad diffuse type or linear band-like type. The former generally respond well to release and insertion of a skin graft or substitute, whereas the latter are generally repaired using a simple or modified Z-plasty or a transpositional flap technique. The pulsed dye laser is a promising technique used to reduce scar thickness and redness. Postburn deformities of the face, upper and lower extremities, and trunk are discussed, in addition to novel techniques for vascularized composite allotransplantation of the face.

Catechol-O-methyltransferase genotype predicts pain severity in hospitalized burn patients.

Increasing evidence suggests that stress system activation after burn injury may contribute to burn-related pain. If this is the case, then genetic variations influencing the function of important stress system components, such as the enzyme catechol-O-methyltransferase (COMT), may predict pain severity after thermal burn injury. The authors evaluated the association between COMT genotype and pain intensity in 57 individuals hospitalized after thermal burn injury. Consenting participants at four burn centers were genotyped and completed daily 0 to 10 numeric rating scale pain assessments on 2 consecutive days including evaluation of waking, least, and worst pain. The association between COMT genotype and individual pain outcomes was calculated using a linear mixed model adjusting for sociodemographic and burn injury characteristics. Overall pain (combination of least, worst, and waking pain scores) was significantly higher in patients with a COMT pain vulnerable genotype (6.3 [0.4] vs 5.4 [0.4], P = .037). Individuals with a COMT pain vulnerable genotype also had significantly higher "least pain" scores (3.8 [0.5] vs 2.6 [0.4], P = .017) and significantly higher pain on awakening (6.8 [0.5] vs 5.3 [0.4], P = .004). Differences in worst pain according to genotype group were not significant. COMT pain vulnerable genotype was a stronger predictor of overall pain severity than burn size, burn depth, or time from admission to pain interview assessment. These findings suggest that genetic factors influencing stress system function may have an important influence on pain severity after burn injury. Further studies of genetic predictors of pain after burn injury are needed.

Percutaneous retrieval of a biliary stent after migration and ileal perforation.

We present a case of a migrated biliary stent that resulted in a distal small bowel perforation, abscess formation and high grade partial small bowel obstruction in a medically stable patient without signs of sepsis or diffuse peritonitis. We performed a percutaneous drainage of the abscess followed by percutaneous retrieval of the stent. The entero-peritoneal fistula closed spontaneously with a drain in place. We conclude, migrated biliary stents associated with perforation distal to the Ligament of Trietz (LOT), may be treated by percutaneous drainage of the abscess and retrieval of the stent from the peritoneal cavity, even when associated with a large intra-abdominal abscess.