A novel multisite confocal system for rapid Ca imaging from submicron structures in brain slices.

In brain slices, resolving fast Ca fluorescence signals from submicron structures is typically achieved using 2-photon or confocal scanning microscopy, an approach that limits the number of scanned points. The novel multiplexing confocal system presented here overcomes this limitation. This system is based on a fast spinning disk, a multimode diode laser and a novel high-resolution CMOS camera.

Mouse Hepatitis Virus Infection Induces a Toll-Like Receptor 2-Dependent Activation of Inflammatory Functions in Liver Sinusoidal Endothelial Cells during Acute Hepatitis.

Unlabelled: Under physiological conditions, the liver sinusoidal endothelial cells (LSECs) mediate hepatic immune tolerance toward self or foreign antigens through constitutive expression of anti-inflammatory mediators. However, upon viral infection or Toll-like receptor 2 (TLR2) activation, LSECs can achieve proinflammatory functions, but their role in hepatic inflammation during acute viral hepatitis is unknown. Using the highly virulent mouse hepatitis virus type 3 (MHV3) and the attenuated variants 51.

Toll-like receptor-2 exacerbates murine acute viral hepatitis.

Viral replication in the liver is generally detected by cellular endosomal Toll-like receptors (TLRs) and cytosolic helicase sensors that trigger antiviral inflammatory responses. Recent evidence suggests that surface TLR2 may also contribute to viral detection through recognition of viral coat proteins but its role in the outcome of acute viral infection remains elusive. In this study, we examined in vivo the role of TLR2 in acute infections induced by the highly hepatotrophic mouse hepatitis virus (MHV) type 3 and weakly hepatotrophic MHV-A59 serotype.

In Vivo Voltage-Sensitive Dye Imaging of Mammalian Cortex Using "Blue" Dyes.

Optical recording of membrane potential allows simultaneous measurements to be taken from many different locations in the nervous system. This is important in studies of the nervous system in which simultaneous activity can occur at the regional, cellular, and subcellular levels. New "blue" dyes, developed by Amiram Grinvald's group, are a great advance for in vivo voltage-sensitive dye imaging of mammalian cortex.

Voltage-Sensitive Dye Imaging of Population Signals in Brain Slices.

In a bright-field measurement from a vertebrate brain stained by superfusing a solution of the dye over the surface, each pixel in a camera receives light from a substantial number (thousands) of neurons and neuronal processes (population signals). Because of scattering and out-of-focus light, this will be true even if the pixel size corresponds to a small area of the brain. In this situation, the voltage-sensitive dye signal will be a population average of the change in membrane potential of all of these neurons and processes.