True and apparent optogenetic BOLD fMRI signals

Purpose

Optogenetic fMRI (ofMRI) is a novel tool in neurophysiology and neuroimaging. The method is prone to light-induced artifacts, two of which were investigated in this study.

Methods

ofMRI was performed in rats using two excitatory opsins (ChR2 and C1V1TT) virally transduced in somatosensory cortex or thalamus. Heat-induced apparent BOLD activation at the site of the optical fiber and stimulation light–induced activation of the visual pathways were investigated, and control experiments for these two artifacts were established.

Results

Specific optogenetic BOLD activation was observed with both opsins, accompanied by BOLD in the visual pathways. Unspecific heat-induced BOLD was ruled out by a control experiment employing low-level constant illumination in addition to pulsed optogenetic stimulation. Activation of the visual pathways was confirmed to be physiological by direct visual stimulation of the eyes and was suppressed by additional low-level constant light to the eyes. Light inside the brain was identified as one source of the BOLD signal observed in the visual pathways.

Conclusion

ofMRI is a method of tremendous potential, but unspecific activations in fMRI not caused by the activation of opsins must be avoided or recognized as such. The control experiments presented here allow for validating the specificity of optogenetic stimulation. Magn Reson Med 77:126–136, 2017. © 2016 Wiley Periodicals, Inc.

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Management of HCV infection in the penitentiary setting in the direct-acting antivirals era: practical recommendations from an expert panel

Abstract

Background

The prevalence of HCV infection is higher among prisoners than in the general population. The introduction of HCV direct-acting antivirals (DAA) holds the potential to improve clinical outcomes also in inmates. However, treatment of hepatitis C in inmates has to face several clinical and logistical issues which are peculiar of prison environment. Recommendations on the management of HCV infection specific for the penitentiary setting in the DAA era remain scant. The Italian Society for Penitentiary Medicine and Healthcare has, therefore, issued these recommendations, to provide clinicians with a guide for the comprehensive management of HCV infection in the restriction setting, taking into account its peculiar characteristics.

Results

Dedicated diagnostic and treatment procedures should be established in each prison. In particular, the use of DAAs appears crucial to provide patients with an effective therapeutic option, able to overcome the limitations of IFN-based regimens with a short period of treatment. DAA treatment should be initiated as soon as possible in all eligible subjects with the aim to cure the patient, as well as to limit the transmission of HCV infection both inside the penitentiary system and to the free community, once the inmates ends his/her release. Importantly, efforts should be made to open a discussion with regulatory bodies, to define specific regulations aimed to guarantee wide access to effective therapies of all eligible patients, to optimize the management of and the adherence to the HCV treatment, and to ensure the therapeutic continuity after discharge from prison.

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Day-case otological surgery

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Publication date: Available online 27 December 2016
Source:European Annals of Otorhinolaryngology, Head and Neck Diseases
Author(s): A. Uziel
The author reviews day-case otological surgery, which has become increasingly popular in France and all over the world over recent years. Ear surgery is particularly suitable for short-stay admission because of the rapidity of these procedures and possibilities of pain control. This article discusses the advantages of this mode of management (for the patient, the surgeon and the healthcare institution), organizational and safety constraints, and ineligibility criteria. Day-case otological surgery should now become the rule rather than an opportunity.

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