Objective: This review details the agents for fluorescence-guided nerve imaging in both preclinical and clinical use to identify factors important in selecting nerve-specific fluorescent agents for surgical procedures. Background: Iatrogenic nerve injury remains a significant cause of morbidity in patients undergoing surgical procedures. Current real-time identification of nerves during surgery involves neurophysiologic nerve stimulation, which has practical limitations. Intraoperative fluorescence-guided imaging provides a complimentary means of differentiating tissue types and pathology. Recent advances in fluorescence-guided nerve imaging have shown promise, but the ideal agent remains elusive. Methods: In February 2018, PubMed was searched for articles investigating peripheral nerve fluorescence. Key terms used in this search include: “intraoperative, nerve, fluorescence, peripheral nerve, visualization, near infrared, and myelin.” Limits were set to exclude articles exclusively dealing with central nervous system targets or written in languages other than English. References were cross-checked for articles not otherwise identified. Results: Of the nonspecific agents, tracers that rely on axonal transport showed the greatest tissue specificity; however, neurovascular dyes already enjoy wide clinical use. Fluorophores specific to nerve moieties result in excellent nerve to background ratios. Although noteworthy findings on tissue specificity, toxicity, and route of administration specific to each fluorescent agent were reported, significant data objectively quantifying nerve-specific fluorescence and toxicity are lacking. Conclusions: Fluorescence-based nerve enhancement has advanced rapidly over the past 10 years with potential for continued utilization and progression in translational research. An ideal agent would be easily administered perioperatively, would not cross the blood-brain barrier, and would fluoresce in the near-infrared spectrum. Agents administered systemically that target nerve-specific moieties have shown the greatest promise. Based on the heterogeneity of published studies and methods for reporting outcomes, it appears that the development of an optimal nerve imaging agent remains challenging.
Accurately identifying close or positive margins in real‐time permits re‐excision during surgical procedures. Intraoperative assessment of margins via gross examination and frozen section is a widely used tool to assist the surgeon in achieving complete resection. While this methodology permits diagnosis of freshly resected tissue, the process is fraught with misinterpretation and sampling errors. During fluorescence‐guided surgery, an exogenous fluorescent agent specific for the target disease is imaged in order to navigate the surgical excision. As this technique quickly advances into the clinic, we hypothesize that the disease‐specific fluorescence inherently contained within the resected tissues can be used to guide histopathological assessment. To evaluate the feasibility of fluorescence‐guided pathology, we evaluated head and neck squamous cell carcinoma tumour specimens and margins resected from animals and patients after systemic injection of cetuximab‐IRDye800CW. In a preclinical model of luciferase‐positive tumour resection using bioluminescence as the gold standard, fluorescence assessment determined by closed‐field fluorescence imaging of fresh resected margins accurately predicted the presence of disease in 33/39 positive margins yielding an overall sensitivity of 85%, specificity of 95%, positive predictive value (PPV) of 94%, and a negative predictive value (NPV) of 87%, which was superior to both surgical assessment (54%, 61%, 57%, and 58%) and pathological assessment (49%, 95%, 91%, and 66%), respectively. When the power of the technique was evaluated using human‐derived tumour tissues, as little as 0.5mg (1mm3) of tumour tissue was identified (tumour‐to‐background‐ratio:5.2). When the sensitivity/specificity of fluorescence‐guided pathology was determined using traditional histological assessment as the gold standard in human tissues obtained during fluorescence‐guided surgery, the technique was highly accurate with a sensitivity of 91%, specificity of 85%, PPV of 81%, and NPV of 93% for 90 human‐derived samples. This approach can be used as a companion to the pathologist, eliminating confounding factors while impacting surgical intervention and patient management.
Epidermolysis bullosa acquisita (EBA) is a rare, subepidermal blistering disease affecting the skin and mucous membranes that often remains refractory to standard immunosuppressive therapy. We present three original cases and a review of the literature of 20 cases of refractory EBA treated with rituximab as monotherapy or in combination with other agents. Complete control (with or without therapy) and remission were seen in 56% of patients treated with rituximab monotherapy and 75% of patients treated with rituximab and immunoadsorption (IA). We conclude EBA refractory to standard immunosuppressive therapy may show a more favorable long‐term response to the addition of rituximab; and rituximab in combination with intravenous immunoglobulin or IA may provide utility in terminating acute disease. Additional data are needed to evaluate the safety and long‐term outcomes of rituximab‐based treatment.
When lichen planus involves the scalp, it is known as lichen planopilaris, and when it involves the eye, it is known as ocular lichen planus; both are rare. Early detection and targeted therapy are crucial in preventing hair loss and scarring conjunctivitis. Little is known regarding appropriate treatment for lichen planopilaris. The objective of this case study is to present a new case of pediatric ocular lichen planus and lichen planopilaris and to identify all reported cases of pediatric lichen planopilaris, highlighting disease involvement, treatment, and response to treatment.
EtO OEt O O EtO OEt O O Pd(dba) 2 t-Bu 2 P t-Bu Ar EtO CN O Ar ArX EtO CN O Base Br: 20 examples Cl: 8 examples Br: 7 examples © 2015. This manuscript version is made available under the Elsevier user licenseAbstract α-Arylated carbonyl derivatives are important structural motifs in many natural products and pharmaceutically active compounds. Although arylation of simple monocarbonyl compounds is a well-established methodology, metal-catalyzed arylation of β-dicarbonyl derivatives is significantly more challenging. The ability ofβ-dicarbonyl anions to bind to palladium in a κ 2 -O,O mode, rather than the κ 1 -C-bound mode required for bond formation, often results in the deactivation of catalyst systems. The C-bound form of the enolate can be favored through the use of sterically demanding ligands. Herein, we report that the sterically demanding di-tertbutylneopentylphosphine (DTBNpP) ligand in combination with Pd(dba) 2 provides an effective catalyst for the coupling of aryl bromides and chlorides with diethyl malonate. The Pd/DTBNpP system also catalyzes the coupling of aryl bromides with ethyl cyanoacetate.
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