Biomedical subjects
Publications and source records attributed to T E Rucinsky.
A pattern of restoration of the smooth gliding surface was noted in lacerated monkey flexor tendon segments maintained in a cell free tissue culture environment over a 9-week period. The epitenon fibroblasts proliferated and migrated into the laceration site, forming collagen fibers that bridged the defect. After the smooth tendon surface was restored, the epitenon cellular response diminished.
About 1% of newly synthesized DNA from PHA-stimulated human lymphocytes can be isolated as large (up to 90 kilobase pairs) double stranded fragments that resist sequential alkali and heat denaturation steps but are not closed circular. By electron microscopy about 1% have single-strand hairpin loops at one end and therefore present inverted repetitive sequences (IR-DNA). Most of the remainder have a blunt-appearing double-strand terminus at both ends (78%) or one end (18%). Indirect evidence indicates that these also are inverted complementary structures with terminal hairpin loops too small to be visualized: (1) Treatment with either a 5' or 3' single-strand exonuclease generates essentially only fragments with a single strand at one end; (2) with partial denaturation, the number of fragments with identifiable single-strand hairpin loops increases (to about 20%); (3) after S1 nuclease digestion, greater than 95% can be fully heat denatured. Cot analysis indicates that these fragments are derived from dispersed sites throughout the genome. Up to 25% of DNA released from lymphocytes during growth similarly resists denaturation, and released DNA and IR-DNA are both enriched in the same set of repetitive sequences. Thus at least a portion of IR-DNA appears to be unstable.
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Examination of immune complexes between cells of Streptococcus mutans and homologous antiserum by the techniques of thin-sectioning and freeze-etching revealed that the cells were embedded within and extensive matrix 80-90 nm thick with defined boundaries.
Exponentially growing cells of the gram-negative bacterium Chromobacterium violaceum demonstrate invaginations of the cytoplasmic membrane with a high frequency. These invaginations conform to the ultrastructural appearance of mesosomes of gram-positive bacteria. As many as four mesosomes are observed per cell, each of which may increase the total membrane surface of the cell by 30%. Washing of cells in dilute tris(hydroxymethyl)aminomethane buffer effects a distension of the mesosome "neck" and/or cytoplasmic membrane clarifying the association of the mesosome to the cytoplasmic membrane. Plasmolysis effects an eversion of the mesosome into the plasmolysis vacuole.
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A strain of Chromobacterium violaceum has been isolated which produces bacteriophage tail-like particles in high numbers. The extracellular morphology and the intracellular arrangement of these particles are described.