Cortical Network Dynamics Is Altered in Mouse Models of Huntington's Disease.

Huntington's disease (HD) is a neurodegenerative disorder characterized by involuntary movements, cognitive deficits, and psychiatric disturbances. Although evidence indicates that projections from motor cortical areas play a key role in the development of dysfunctional striatal activity and motor phenotype, little is known about the changes in cortical microcircuits and their role in the development of the HD phenotype. Here we used two-photon laser-scanning microscopy to evaluate network dynamics of motor cortical neurons in layers II/III in behaving transgenic R6/2 and knock-in Q175+/- mice. Symptomatic R6/2 mice displayed increased motion manifested by a significantly greater number of motion epochs, whereas symptomatic Q175 mice displayed decreased motion. In both models, calcium transients in symptomatic mice displayed reduced amplitude, suggesting decreased bursting activity. Changes in frequency were genotype- and time-dependent; for R6/2 mice, the frequency was reduced during both motion and nonmotion, whereas in symptomatic Q175 mice, the reduction only occurred during nonmotion. In presymptomatic Q175 mice, frequency was increased during both behavioral states. Interneuronal correlation coefficients were generally decreased in both models, suggesting disrupted interneuronal communication in HD cerebral cortex. These results indicate similar and contrasting effects of the HD mutation on cortical ensemble activity depending on mouse model and disease stage.

Necrolytic acral erythema in a human immunodeficiency virus/hepatitis C virus coinfected patient: A case report.

BACKGROUND: Necrolytic acral erythema (NAE) is a rare dermatological disorder, which is associated with hepatitis C virus (HCV) infection or zinc deficiency. It is characterized by erythematous or violaceous lesions occurring primarily in the lower extremities. The treatment includes systemic steroids and oral zinc supplementation. We report a case of NAE in a 66-year-old human immunodeficiency virus (HIV)/HCV co-infected woman with NAE. NAE is rarely reported in co-infected patients and the exact mechanisms of pathogenesis are still unclear. CASE SUMMARY: A 66-year-old HIV/HCV co-infected female patient presented with painless, non-pruritic rash of extremities for one week and underwent extensive work-up for possible rheumatologic disorders including vasculitis and cryoglobulinemia. Punch skin biopsies of right and left thigh revealed thickened parakeratotic stratum corneum most consistent with NAE. Patient was started on prednisone and zinc supplementation with resolution of the lesions and improvement of rash. CONCLUSION: Clinicians should maintain high clinical suspicion for early recognition of NAE in patients with rash and HCV.