Compact Electrochromic Optical Recording of Bioelectric Potentials.

Electrochromic optical recording (ECORE) is a label-free method that utilizes electrochromism to optically detect electrical signals in biological cells with a high signal-to-noise ratio and is suitable for long-term recording. However, ECORE usually requires a large and intricate optical setup, making it relatively difficult to transport and to study specimens on a large scale. Here, we present a Compact ECORE (CECORE) apparatus that drastically reduces the spatial footprint and complexity of the ECORE setup whilst maintaining high sensitivity. An autobalancing differential photodetector automates common-mode noise rejection, removing the need for manually adjustable optics, and a compact laser module conserves space compared to a typical laser mount. The result is a simple, easy-to-use, and relatively low cost system that achieves a sensitivity of 16.7 µV (within a factor of 5 of the shot noise limit), and reliably detects action potentials from Human-induced pluripotent stem cell (HiPSC) derived cardiomyocytes. This setup can be further improved to within 1.5 dB of the shot noise limit by filtering out power-line interference.

Dual-Color Optical Recording of Bioelectric Potentials by Polymer Electrochromism.

Optical recording based on voltage-sensitive fluorescent reporters allows for spatial flexibility of measuring from desired cells, but photobleaching and phototoxicity of the fluorescent labels often limit their sensitivity and recording duration. Voltage-dependent optical absorption, rather than fluorescence, of electrochromic materials, would overcome these limitations to achieve long-term optical recording of bioelectrical signals. Electrochromic materials such as PEDOT:PSS possess the property that an applied voltage can either increase or decrease the light absorption depending on the wavelength. In this work, we harness this anticorrelated light absorption at two different wavelengths to significantly improve the signal detection. With dual-color detection, electrical activity from cells produces signals of opposite polarity, while artifacts, mechanical motions, and technical noises are uncorrelated or positively correlated. Using this technique, we are able to optically record cardiac action potentials with a high signal-to-noise ratio, 10 kHz sampling rate, >15 min recording duration, and no time-dependent degradation of the signal. Furthermore, we can reliably perform multiple recording sessions from the same culture for over 25 days.

Vesiculobullous disease with Cutaneous Systemic Lupus Erythematosus Treated by Rituximab: A case report.

Vesiculobullous lesions in systemic lupus erythematosus (SLE) are a rare cutaneous manifestation of cutaneous and/or systemic LE with variable presentation. The diagnosis of SLE-associated vesiculobullous diseases remains challenging, due to the poorly defined similarities and nosology in immunohistopathological and clinical and features.

Telogen hair loss and androgenetic-like alopecia in GAPO syndrome.

Growth retardation, Alopecia, Pseudoanodontia and Optic atrophy (GAPO) syndrome is a rare autosomal recessive condition whose cardinal features include a recognizable craniofacial dysmorphosis, growth retardation, alopecia, pseudoanodontia, and premature aging. We report on a 2-year-old Pakistani man affected with GAPO syndrome who additionally shows an androgenetic-like alopecia with normal testosterone levels and telogen hair loss. These are novel findings in GAPO syndrome.