Quantitative myelin imaging with MRI and PET: an overview of techniques and their validation status.

Myelin is the protective sheath wrapped around axons, consisting of a phospholipid bilayer with water between the wraps. The measurement of damage to the myelin sheaths, the evaluation of the efficacy of therapies aiming to promote remyelination and monitoring the degree of brain maturation in children all require non-invasive quantitative myelin imaging methods. To date, various myelin imaging techniques have been developed. Five different MRI approaches can be distinguished based on their biophysical principles: (i) imaging of the water between the lipid bilayers directly (e.g. myelin water imaging); (ii) imaging the non-aqueous protons of the phospholipid bilayer directly with ultra-short echo-time techniques; (iii) indirect imaging of the macromolecular content (e.g. magnetization transfer; inhomogeneous magnetization transfer); (iv) mapping of the effects of the myelin sheath's magnetic susceptibility on the MRI signal (e.g. quantitative susceptibility mapping); and (v) mapping of the effects of the myelin sheath on water diffusion. Myelin imaging with PET uses radioactive molecules with high affinity to specific myelin components, in particular myelin basic protein. This review aims to give an overview of the various myelin imaging techniques, their biophysical principles, image acquisition, data analysis and their validation status.

Lived Experiences of Sexuality and Sexual Functioning in Males with SCI: A Mixed-Methods Study.

Background: Sexual dysfunction is highly prevalent in males with spinal cord injury (SCI) and has been recognized to be a key recovery priority. Objectives: This cross-sectional, mixed-methods study aimed to investigate the major themes linked to sexual functioning in males with chronic (>1 year) SCI. Methods: Twenty male participants with SCI, aged 25 to 59 years, completed validated questionnaires exploring sexual function/satisfaction and health-related quality of life and a semi-structured interview with an experienced sexual medicine physician. Sex hormone concentrations and metabolic biomarkers, along with body composition and habitual physical activity levels, were assessed. Interview recordings were transcribed and thematic analysis performed using combined COM-B (Capability, Opportunity, Motivation, and Behavior) and biopsychosocial models to identify and organize major contributors and barriers to sexual functioning. Results: Metabolic and hormonal biomarkers largely fell within normal physiological ranges despite reduced sexual functioning reported in our cohort (19/20 participants reported some degree of erectile dysfunction). Qualitative analysis of interview transcripts revealed 24 themes. Adaptability was important for improving sexual satisfaction. Attraction and attentiveness to sex and partners remained stable over time, while the desire for intimacy increased post injury. Sexual social norms, and comparisons to the able-bodied population, provided challenges for sexual activity and partnership. Environmental concerns regarding access to sexual health resources and accessible physical spaces during intimacy were relevant. Mood disorders and general life stressors negatively impacted sexual desire, while physical activity encouraged sexual activity. Conclusion: By considering a holistic view of sexuality in males with SCI, we identified key contributors and barriers to sexual functioning for the cohort studied.

Evidence for Anti-Pseudogymnoascus destructans (Pd) Activity of Propolis.

White-nose syndrome (WNS) in bats, caused by Pseudogymnoascus destructans (Pd), is a cutaneous infection that has devastated North American bat populations since 2007. At present, there is no effective method for controlling this disease. Here, we evaluated the effect of propolis against Pd in vitro. Using Sabouraud dextrose agar (SDA) medium, approximately 1.7 × 107 conidia spores of the Pd strain M3906-2/mL were spread on each plate and grown to form a consistent lawn. A Kirby-Bauer disk diffusion assay was employed using different concentrations of propolis (1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%), in plates incubated at 8 °C and 15 °C. At 8 °C and 15 °C, as the concentration of propolis increased, there was an increasing zone of inhibition (ZOI), reaching the highest degree at 10% and 25% concentrations, respectively. A germule suppression assay showed a similar effect on Pd conidia germination. A MALDI-TOF-MS analysis of propolis revealed multiple constituents with a potential anti-Pd activity, including cinnamic acid, p-coumaric acid, and dihydrochalcones, which could be further tested for their individual effects. Our study suggests that propolis or its individual constituents might be suitable products against Pd.