Inhibition of central nervous system axon growth is reportedly mediated in part by calcium-dependent phosphorylation of axonal epidermal growth factor receptor, with local administration of the epidermal growth factor receptor kinase inhibitors AG1478 and PD168393 to an optic nerve lesion site promoting adult retinal ganglion cell axon regeneration. Here, we show that epidermal growth factor receptor was neither constitutively expressed, nor activated in optic nerve axons in our non-regenerating and regenerating optic nerve injury models, a finding that is inconsistent with phosphorylated epidermal growth factor receptor-dependent intra-axonal signalling of central nervous system myelin-related axon growth inhibitory ligands. However, epidermal growth factor receptor was localized and activated within most glia in the retina and optic nerve post-injury, and thus an indirect glial-dependent mechanism for stimulated retinal ganglion cell axon growth by epidermal growth factor receptor inhibitors seemed plausible. Using primary retinal cultures with added central nervous system myelin extracts, we confirmed previous reports that AG1478/PD168393 blocks epidermal growth factor receptor activation and promotes disinhibited neurite outgrowth. Paradoxically, neurites did not grow in central nervous system myelin extract-containing cultures after short interfering ribonucleic acid-mediated knockdown of epidermal growth factor receptor. However, addition of AG1478 restored neurite outgrowth to short interfering ribonucleic acid-treated cultures, implying that epidermal growth factor receptor does not mediate AG1478-dependent effects. TrkA-/B-/C-Fc fusion proteins and the kinase blocker K252a abrogated the neuritogenic activity in these cultures, correlating with the presence of the neurotrophins brain derived neurotrophic factor, nerve growth factor and neurotrophin-3 in the supernatant and increased intracellular cyclic adenosine monophosphate activity. Neurotrophins released by AG1478 stimulated disinhibited retinal ganglion cell axon growth in central nervous system myelin-treated cultures by the induction of regulated intramembraneous proteolysis of p75(NTR) and Rho inactivation. Retinal astrocytes/Müller cells and retinal ganglion cells were the source of neurotrophins, with neurite outgrowth halved in the presence of glial inhibitors. We attribute AG1478-stimulated neuritogenesis to the induced release of neurotrophins together with raised cyclic adenosine monophosphate levels in treated cultures, leading to axon growth and disinhibition by neurotrophin-induced regulated intramembraneous proteolysis of p75(NTR). These off-target effects of epidermal growth factor receptor kinase inhibition suggest a novel therapeutic approach for designing treatments to promote central nervous system axon regeneration.

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Urinary incontinence remains an important clinical problem worldwide, having a significant socio-economic, psychological, and medical burden. Maintaining urinary continence and coordinating micturition are complex processes relying on interaction between somatic and visceral elements, moderated by learned behavior. Urinary viscera and pelvic floor must interact with higher centers to ensure a functionally competent system. This article aims to describe the relevant anatomy and neuronal pathways involved in the maintenance of urinary continence and micturition. Review of relevant literature focusing on pelvic floor and urinary sphincters anatomy, and neuroanatomy of urinary continence and micturition. Data obtained from both live and cadaveric human studies are included. The stretch during bladder filling is believed to cause release of urothelial chemical mediators, which in turn activates afferent nerves and myofibroblasts in the muscosal and submucosal layers respectively, thereby relaying sensation of bladder fullness. The internal urethral sphincter is continuous with detrusor muscle, but its arrangement is variable. The external urethral sphincter blends with fibers of levator ani muscle. Executive decisions about micturition in humans rely on a complex mechanism involving communication between several cerebral centers and primitive sacral spinal reflexes. The pudendal nerve is most commonly damaged in females at the level of sacrospinous ligament. We describe the pelvic anatomy and relevant neuroanatomy involved in maintaining urinary continence and during micturition, subsequently highlighting the anatomical basis of urinary incontinence. Comprehensive anatomical understanding is vital for appropriate medical and surgical management of affected patients, and helps guide development of future therapies.

Background: Acute interstitial nephritis (AIN) is a common cause of acute kidney injury and is characterised by a dense interstitial cellular infiltrate, which has not been well defined. Previous studies have demonstrated a correlation between Epstein-Barr virus (EBV) infection and AIN. The purpose of our study was to define the nature of the interstitial immune infiltrate and to investigate the possibility of renal infection with EBV. Methods: Seventy-eight patients with AIN were identified from renal biopsy reports in a single centre over an 18-year period. Immunohistochemical staining was performed to define the cellular infiltrate. In situ hybridization and immunohistology were used to detect EBV. Results: A positive correlation between CD68 macrophage infiltration and serum creatinine concentration at presentation was identified. IL-4, eotaxin, CCR3, CCR5 and VCAM-1 were all expressed in biopsies of AIN. Using in situ hybridization and immunohistochemistry, EBV was not detected in any of the AIN sections analysed. Conclusion: This study has assessed the nature of the interstitial infiltrate in AIN. EBV was not detected in the renal biopsies, suggesting that EBV is not a pathogenetic factor in AIN.