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Biomedical subjects

R G Bird

Publications and source records attributed to R G Bird.

At least 19 recordsLinked to original sources
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↗
PubMed1982

Non-A, non-B hepatitis: a case report.

Ultrastructural changes in a liver biopsy obtained for diagnostic purposes from a patient with suspected non-A, non-B hepatitis were consistent with hepatitis and included dilatation and disaggregation of the endoplasmic reticulum, hepatocyte disarray, and variations in mitochondrial size. In addition, some foci of hepatocytes showed atypical cytoplasmic changes including intranuclear cytoplasmic pseudo-inclusions, consisting basically of invaginations of the cytoplasmic mass into the nucleus, glycogen deposits in the same nuclei, and frequently accumulations of fat droplets. The mitochondria were generally pleomorphic, and occasionally the mitochondrial cristae were arranged longitudinally. Dilatation, hypertrophy, and distortion of the Golgi complexes were found in affected hepatocytes. Similar ultrastructural changes have previously been reported in human hepatocellular carcinoma as well as in carcinomas of other tissues.

Cell Nucleus↗
PubMed1981

The fine structural relationship between Theileria schizonts and infected bovine lymphoblasts from cultures.

The fine structure of Theileria-lymphoblast relationship was studied using cultured bovine lymphoblastoid cells infected with Theileria parva, T lawrencei, or T. annulata. The major findings of this study were: (1) the presence of a very active Golgi complex with the associated annulate lamelae; (b) the presence of cytoplasmic microtubules which joined the parasites and host cell centriole during lymphoblast mitosis; and (c) the absence of morphological evidence to suggest that the host cell developed a reaction to the parasitic presence. The significance of these findings is discussed.

Animals↗
PubMed1981

Ultrastructural changes in the liver in experimental non-A, non-B hepatitis.

Factor VIII, a blood-clotting derivative prepared from pooled human plasma, previously shown to cause a short-incubation-period non-A, non-B hepatitis in patients and in chimpanzees, was studied further to establish the nature of the pathological lesions associated with this infection. Percutaneous liver biopsy specimens were examined in detail. Cytoplasmic changes in the hepatocytes were observed on the 7th day after inoculation in one instance and after 13 days in the second, and persisted in the biopsy specimens for 13 weeks after infection. Abnormalities in hepatocyte nuclei, including aggregates of irregularly shaped particles 15-20 nm in size, were observed about 1 week after the onset of the cytoplasmic changes. The ultrastructural changes are described and their nature and significance discussed. Attention is drawn to somewhat similar cytoplasmic and nuclear changes occurring in other disease entities.

Animals↗
PubMed1980

Further evidence of cellular changes associated with non-A, non-B hepatitis.

Two distinct types of ultrastructural changes were found in the hepatocytes of chimpanzees infected with two forms of non-A, non-B hepatitis. In the type of infection that was of long incubation, there was a marked cytoplasmic derangement of the endoplasmic reticulum, with the formation of tubules, but no pathological changes in the nuclei. In the short-incubation type of non-A, non-B hepatitis, induced experimentally in a chimpanzee that had recovered from the long-incubation type of infection, nuclear alterations were found together with the presence of aggregates of particles measuring 15--27 nm in diameter. Cytoplasmic tubules were not seen in this type of non-A, non-B infection.

Animals↗
PubMed1980

Cryptosporidiosis in man: parasite life cycle and fine structural pathology.

The Cryptosporidium here described is a very small (3-4 micron) opportunistic pathogenic coccidian parasite. Through seven known human enteric infections it is now associated with diarrhoea in immunosuppressed or immunodeficient individuals. Neither the full pathogenic potential nor the complete life cycle of this parasite are known, and there is no adequate chemotherapeutic agent with which to eradicate it. What is known of its intracellular intestinal forms and the fine structural changes occurring in parasitised epithelial cells has been described. A viral complication of the infection is discussed and mention is made of relevant cryptosporidial infections of domestic and other animals.

Adenovirus Infections, Human↗
PubMed1978

Mycobacteria as a possible cause of inflammatory bowel disease.

Mesenteric lymph-nodes from 27 patients with Crohn's disease, 13 with ulcerative colitis, and 11 without inflammatory bowel disease were cultured for mycobacteria. A node from a patient with Crohn's disease yielded a strain of Mycobacterium kansasii. Cultures from 22 other patients with Crohn's disease, 7 with ulcerative colitis, and 1 control subject yielded pleomorphic organisms with the electron-microscopic appearances of cell-wall-deficient organisms. Further culture and characterisation of these organisms has so far proved unsuccesful. Skin tests with tuberculin were positive in a smaller proportion of patients with Crohn's disease than in healthy control subjects. Conversely, the patients gave a higher proportion of positive reactions to a reagent prepared from the strain of M. kansasii isolated. No differences in the proportion of positive test were found between patients and controls with reagents prepared from 16 other mycobacteria. Cell-wall-deficient mycobacteria are a possible causative agent of inflammatory bowel disease.

Adolescent↗
PubMed1978

Lysogeny associated with mucoid variation in Mycobacterium kansasii.

Ten of 200 strains of Mycobacterium kansasii were found to produce very mucoid growth on Löwenstein-Jensen medium. By electronmicroscopy these 10 strains were found to be lysogenic, whereas no phage was observed in cultures of 30 non-mucoid strains. The cultural and biochemical properties of the lysogenic strains are compared with those of non-lysogenic strains, and the morphology of the phages is described.

Amidohydrolases↗
PubMed1977

Correlations between the detection of e antigen or antibody and electron microscopic pattern of hepatitis B surface antigen (HBsAg) associated particles in the serum of HBsAg carriers.

The distribution of HBsAg associated particles, especially the presence of Dane particles, was studied by electron microscopy in coded sera of 68 chronic HBsAg carriers. Results were correlated with the detection of eAg or Ab and clinical diagnosis. Sera from haemodialysis and chronic hepatitis patients showed a high prevalence of e antigenaemia (9/13, 69-2% and 8/19, 42-1%) and Dane particles (11 and 16 respectively, 84%). By contrast, out of 36 chronic asymptomatic carriers of HBsAg, 28 (77-7%) were positive for e antibody but only 1 (2-7%) had eAg. Dane particles were found in 13/36 (36-1%). A statistically significant correlation was observed between the detection of eAg and the presence of Dane particles (94-4%) in the serum. However, Dane particles were still observed in 10/28 (35-7%) of anti-e positive sera. The data suggest that eAg may be linked to complete HB virions.

Antibodies↗
PubMed1976

The rhabdoviruses of Entamoeba histolytica and Entamoeba invadens.

Rhabdoviruses have been described in plants, arthropods and vertebrates including man. Members of the group are of agricultural, veterinary and medical importance. The presence of a rhabdovirus in Entamoeba histolytica and Entamoeba invadens is the first record of their existence within protozoa. The morphology of this virus is described and its significance discussed, in relation to a possible lysogenic state and pathogenecity of Entamoeba species.

Animals↗