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R G Christian

Publications and source records attributed to R G Christian.

13 recordsLinked to original sources
PubMed1982

Observations of abnormalities and age-related changes in the anconeal processes of swine.

Abnormalities and age-related changes in the anconeal processes of 60 boars were studied. Postmortem examination of both cubitus joints from 25 lame adolescent boars and from 5 of their nonlame contemporaries revealed cartilaginous tissue (termed cartilage plate) of varying size between the anconeal process and the ulnar diaphysis in 8 of the lame animals. The cartilage plate was fractured in both joints from 7 of these 8 animals, and joints from 6 animals with cartilage plate were associated with lesions of the semilunar articular cartilage and bone in the proximal portion of the ulna. Postmortem examination of the joints from 30 boars (ranging in age from 1 month before birth to 1.5 years) indicated that during growth, bone developed from the ulnar diaphysis toward the cranial tip of the anconeal process. Separate ossification centers were not observed in any of the clinically normal anconeal processes studied in this group. However, microscopic observations of 1 abnormal anconeal process from a 13-week-old boar indicated that trauma may be involved in morphogenesis of a cartilage plate. Age-dependent changes were also observed in the composition of the anconeal process.

Aging↗
PubMed1981

Age related changes and osteochondrosis in swine articular and epiphyseal cartilage: light ane electron microscopy.

Age related changes and osteochondrosis in swine were studied using light microscopy and electron microscopy in articular cartilage and light microscopy and epiphyseal cartilage of swine from three days to 30 weeks of age. Thickness, cellularity and vascularity of both the epiphyseal and articular cartilage, decreased as the swine aged. Osteochondrotic changes included formation of "plugs" of cartilage indicating localized failure of ossification and separation and space formation in epiphyseal cartilage. Eosinophilic streaks and space formation in epiphyseal cartilage was observed in relation to epiphyseal separation. Electron microscopy showed a continuous fibrillar layer on the surface of the cartilage corresponding to the lamina splendens of light microscopy. This layer increased in the thickness and showed accumulation of amorphous material between the fibrils with aging. In the matrix, the orientation and distribution of the collagen fibers changed with growth and thicker fibers with clear sub banding were more common in older age groups. Also, necrotic cells, glycogen containing bodies and cellular debris were noticed in the matrix of normal cartilage in old animals. Chondrocytes in the younger cartilage showed accumulation of organelles responsible for protein synthesis; while Golgi bodies, vesicles, lysosomes, well developed foot processes and other inclusions were noticed in older cartilage. Cartilage erosions had a clumped and disrupted lamina splendens on the surface and electron lucent patches in the ground substances of the matrix and chondrocyte cytoplasm.

Aging↗
PubMed1977

Synthesis of ribonucleotides and their participation in ribonucleic acid synthesis by Coxiella burnetii.

Synthesis of ribonucleic acid (RNA) by the deoxyribonucleic acid-dependent RNA polymerase of Coxiella burnetii required adenosine, uridine, guanosine, and cytidine 5'-triphosphates. Cell-free preparations of this obligate intracellular procaryotic parasite had competence to phosphorylate ribonucleoside mono- and diphosphates in the presence of exogenous adenosine and guanosine 5'-triphosphates to the corresponding di- and triphosphates. C. burnetii contained about 2 nmol of adenosine 5'-triphosphate per mg of protein, which could serve as a approximately P donor for in vivo synthesis of nucleoside triphosphates. The latter were then used as substrates in the synthesis of RNA in a coordinated metabolic system with C. burnetii RNA polymerase. It is suggested that during infection the rickettsiae might obtain the nucleotides necessary for RNA synthesis from the vacuoles in which C. burnetii proliferates.

Adenosine Triphosphate↗
PubMed1977

Electron microscopy of rapid identification of animal viruses in hematoxylin-eosin sections.

Routine hematoxylin-eosin stained, paraffin sections were processed for electron microscopy, using a rapid method for localization of animal viruses. Formalin fixation was effective in preserving DNA as well as RNA viruses, however cellular fine structural details and organelles were not well preserved. The procedure is useful for morphological recognition of viral groups and as a rapid diagnostic aid for identifying viral disease.

Animals↗