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Publisher Summary The chapter discusses methods and concepts that facilitate the detection and identification of single molecules of mRNA in situ using fluorescence in situ hybridization (FISH). FISH is a very widely used technique in cell biology. The sensitivity of detection is the major concern when implementing the FISH technology. The methodology employs stringent imaging requirements that include a carefully calibrated quantitative epifluorescence digital imaging microscope, three-dimensional (3D) optical sectioning, constrained iterative deconvolution, and 3D interactive analysis software. The analysis of point sources representing one hybridized probe has provided additional information concerning the nature of the imaging process. The pixel does not suffice as the unit for analysis of a digital image involving fluorescence in situ hybridization. The detailed characterization of biological molecules in situ is now possible using FISH. Unprecedented detail can be revealed from a hybridized cell that has been interrogated with carefully engineered, quantitatively accurate probes, followed by three-dimensional imaging and deconvolution.

Publisher Summary This chapter describes the responses of joint afferent neurons to loadings of isolated joint capsule. It describes preliminary experiments that were performed in which sections of knee joint capsule, with intact sensory innervation, were excised from the cat knee, and subjected to various loadings in vitro, similar to the experiments described by Eklund & Skoglund. Given the properties of joint afferents observed in isolated capsule sections, the problem was to devise a configuration for loading the capsule so that the stress on the inner surface could be measured and controlled. The experimental design included transverse loading with both spherical and cylindrical probes. Each capsule section was tested for a neuronal response to pure axial loading. All capsule sections were highly sensitive to transverse loading. Transverse and axial loads were confounded in these experiments as the application of the transverse load increased the axial load.

A method for directly determining strains in soft tissue has been developed. Markers are attached to the tissue to form a grid. The tissue is photographed in the undeformed configuration and then in a series of deformed (loaded) configurations. Using a digitizer, nodal coordinates are entered into a computer from the photographs. A finite element program then calculates the Lagrangian finite strain tensor at each of the nodes. The method has been used in both in vivo and in vitro situations.