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Biomedical subjects

R W Horne

Publications and source records attributed to R W Horne.

At least 19 recordsLinked to original sources
PubMed1982

Digital processing methods for structural analysis of an electron micrograph.

Digital processing method using the scanning-densitometer with microcomputer provides a useful description system. It draws attention to the usefulness of local lattice averaging in clarifying images of periodic structures in crystals as well as crystalloids and para crystalline arrays in biological specimens. Digital processing of lattice images in crystal structures from the selected diffraction spots is successfully developed to the structural analysis of evaporated gold, graphitized carbon and human tooth enamel of hydroxyapatite. Furthermore, known microbody crystalloids in enzyme and icosahedral capsids in virus are confirmed and clarified by the procedure of selecting diffraction spectra transformed from the information taken with high resolution electron micrographs. The processed results can provide significant improvements in structural analysis of an electron micrograph.

Crystallography↗
PubMed1979

An historical account of the development and applications of the negative staining technique to the electron microscopy of viruses.

A brief historical account of the development and applications of the negative staining techniques to the study of the structure of viruses and their components as observed in the electron microscope is presented. Although the basic method of surrounding or embedding specimens in opaque dyes was used in light microscopy dating from about 1884, the equivalent preparative techniques applied to electron microscopy were comparatively recent. The combination of experiments on a sophisticated bacterial virus and the installation of a high resolution electron microscope in the Cavendish Laboratory, Cambridge, during 1954, subsequently led to the analysis of several important morphological features of animal, plant and bacterial viruses. The implications of the results from these early experiments on viruses and recent developments in negative staining methods for high resolution image analysis of electron micrographs are also discussed.

Animals↗
PubMed1978

Special specimen preparation methods for image processing in transmission electron microscopy: a review.

One of the important developments in quantitative electron microscopy has been the application of optical and computer imaging methods to electron micrographs. In general these techniques of image analysis have been applied to electron micrographs from isolated biological structures prepared in the presence of various negative stains. To make full use of image processing techniques there are obvious advantages in preparing suitable specimens containing large areas of repeating features. However, the number of naturally occurring biological specimens exhibiting crystalline or paracrystalline features suitable for high resolution electron microscopy and subsequent image analysis is relatively small.Some recent experiments on the in vitro formation of crystalline and paracrystalline arrays from highly concentrated and purified isometric, filamentous and rod-like viruses is reviewed. The problems associated with the preparative procedures for producing two-dimensional and three-dimensional crystalline arrays are discussed together with the possibility of extending the negative staining-carbon film method for studying the gradual dissociation or assembly of viral components.

Computers↗
PubMed1976

Assembly of flexuous plant viruses and their proteins.

Recent experiments on the disassembly and assembly of some flexuous plant viruses and their proteins are described. The properties of reconstituted potato virus X and those of assembled potato virus Y protein are considered as well as the suitability of other flexuous viruses for reconstitution studies.

Plant Viruses↗
PubMed1976

Cryoimmunoglobulin IgGk with microtubular ultrastructure associated with pyoderma gangrenosum.

Recurrent gangrenous leg ulcers were associated with a monoclonal IgGk cryoglobulinaemia, though without overt myeloma. Cryoprecipitation of the serum in vitro gave a reversible gel with microtubular structure, built from the monomer and with a high degree of order. The same structure was found distending the superficial vessels of the ulcer biopsy, as well as extravascularly. There was no vasculitis, and luminal obstruction appeared responsible for the ulceration. Microtubular structures occur in nature among diverse proteins and viruses. The protein studied here is similar to a reported instance of myeloma cryo-IgGk.

Blood Vessels↗
PubMed1976

Electron microscopy of tobacco mosaic virus prepared with the aid of negative staining-carbon film techniques.

The negative staining-carbon technique has been applied to suspensions of freshly prepared type strain tobacco mosaic virus particles in high concentrations. Electron microscope images show that paracrystalline arrays of the virus were formed, in which large areas of rods could be viewed along their long axes and in parallel arrays in horizontal positions. High-resolution micrographs showed the protein structure units in rods photographed in both vertical and horizontal orientations.

Crystallography↗