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Biomedical subjects

R L Chandler

Publications and source records attributed to R L Chandler.

At least 19 recordsLinked to original sources
PubMed1985

Exposure of bovine cornea to different strains of Moraxella bovis and to other bacterial species in vitro.

A collection of strains of Moraxella bovis, some pathogenic and some non-pathogenic in cattle, together with other M. bovis preparations, Neisseria ovis, Staphylococcus aureus and Moraxella non-liquefaciens were studied by scanning electron microscopy for their affinity to bovine corneal preparations in vitro. The in vitro procedure provides a convenient method for studies on host-pathogen interactions at the early stage of pathogenesis. The results corresponded well with the pathogenicity of the respective strains and species in cattle. It is considered that the pathogenicity of M. bovis is associated with at least two factors, piliation and the ability to produce pit-like depressions in corneal epithelial cells. The other bacterial species, which are not thought to play an important role in infectious bovine keratoconjunctivitis, had the ability to adhere to the bovine cornea but did not produce pits. The pitting factor of M. bovis is of interest in relation to studies on vaccination against infectious bovine keratoconjunctivitis.

Animals↗
PubMed1983

Scanning electron microscope studies on preparations of bovine cornea exposed to Moraxella bovis.

Preparations of bovine cornea were studied by scanning electron microscopy before and after in vitro exposure to Moraxella bovis. The bacteria were observed in association with the surface of the corneal epithelium; they showed a predilection for dark cells relatively devoid of surface structure. Pit-like depressions related to the presence of individual bacteria were produced in these cells. An evident association with corneal epithelium was shown by 2 strains known to be pathogenic experimentally in cattle but not by 2 non-pathogenic strains.

Animals↗
PubMed1983

Laboratory model for infectious bovine keratoconjunctivitis: the pathogenicity of different strains of Moraxella bovis, pathology and ultrastructural observations.

Further studies were made using C57 mice pretreated with a corticosteroid and inoculated with Moraxella bovis by instillation, as a model for infectious bovine keratoconjunctivitis. Strains of M bovis which had previously been tested in cattle produced a generally similar range of pathogenicity when tested in mice. The pathology in the mouse model closely resembled that in cattle and the value of the model for studies on M bovis was confirmed.

Animals↗
PubMed1982

Development of a laboratory animal model for infectious bovine keratoconjunctivitis.

Guinea pigs, gerbils, voles, golden hamsters and Chinese hamsters exposed to experimental infection with Moraxella bovis by ocular instillation or associated routes showed transient infections only and no clinical signs. Five strains of mice were of similarly low susceptibility but another, the C57 Bl strain, was relatively susceptible and treatment with corticosteroid before infection regularly produced keratoconjunctivitis. This system therefore offers a promising model for studies on infectious bovine keratoconjunctivitis.

Animals↗
PubMed1978

A freeze-etching study on experimental murine mastitis.

Streptococcal mastitis was produced experimentally in mice inoculated by the intramammary route; freeze-etched preparations from the affected mammary glands were studied by electron microscopy. The inoculated cocci were seen free in the acinar lumen, within luminal phagocytes and within cells of the epithelium. No significant pathological changes were noted in the junctional complexes between secretory epithelial cells. The results were comparable to those obtained by ultrathin sectioning and indicated that, while cocci can transfer from the acinar lumen into the substance of the epithelium and towards a subepithelial location, the junctional complexes between epithelial cells present a potential barrier to movement through the intercellular spaces.

Animals↗
PubMed1976

Gnotobiotic piglets experimentally infected with neonatal calf diarrhoea reovirus-like agent (Rotavirus).

Gnotobiotic piglets were infected with a strain of rotavirus that had been isolated from a calf and passaged four times in piglets. The resulting disease was studied by light and electron microscopy at 21, 44 and 68 h after inoculation. In the small intestine infection caused desquamation of the epithelial cells of the villi resulting in severe stunting. There was severe damage to microvilli and accumulation of lipid within the cytoplasm. Virus particles were seen in epithelial cells covering the stunted villi. Infection also caused desquamation of the superficial epithelial cells of the stomach mucosa and of the epithelial cells of the bronchi, bronchioles, and alveoli of the lungs.

Animals↗