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T F McCaul

Publications and source records attributed to T F McCaul.

33 records · Page 2Linked to original sources
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↗
PubMed1982

Application of electron microscopy to the study of structural changes in the liver in non-A, non-B hepatitis.

Ultrastructural studies employing techniques such as alternative electron metal stain, high-angle tilting and high-voltage electron microscopy were carried out on liver biopsies obtained from chimpanzees infected with non-A, non-B hepatitis. Typical derangement of the endoplasmic reticulum leading to the formation of tubular structures in hepatocytes was observed. The use of potassium permanganate as an alternative stain revealed two features which have not been previously described. The first of these shows the wall of the tubular structures to be composed of a well-defined fibrillar-like meshwork with a periodicity of approximately 15 nm. The second feature is the demonstration of clusters of fibrin-like inclusions consisting of striated fibrils in the neighborhood of the tubular structures. The presence of intracytoplasmic fibrin may indicate non-specific morphological evidence of cell injury. Crystalline structures containing arrays of particles with an average size of 24 nm were also observed in the endoplasmic reticulum of endothelial cells of the hepatic sinusoids. Morphological differences between the crystalline lattice and the reticular arrangement, demonstrated with the use of high-angle tilting of the specimen in the electron microscopy suggest that the arrays may not be viral particules but a reflection of pathological response of the host cell.

Animals↗
PubMed1982

A study of ultrastructural alterations in experimental non-A, non-B hepatitis by electron-beam analysis.

An electron-beam X-ray microanalysis was carried out on sections of liver biopsy specimens obtained from chimpanzees infected with non-A, non-B hepatitis. The microanalysis was concentrated over areas where typical derangement of the endoplasmic reticulum, with the formation of tubular forms possessing walls with electron-dense central membrane, was visualized. These tubular structures are regarded as the most notable pathological alteration in affected hepatocytes. However, the electron-probe microanalysis showed no deviation of the energy spectrum when compared with the background or control analysis.

Animals↗
PubMed1981

Immunological and biological characterization of Coxiella burnetii, phases I and II, separated from host components.

Coxiella burnetii, phase I and II, cells cultivated in the yolk sac of chicken embryos were separated from host cell components by two cycles of isopycnic Renografin gradient centrifugation. Initial steps in the purification of viable C. burnetii involved differential centrifugation and sedimentation through an aqueous solution of 30% sucrose and 7.6% Renografin. After the first, but not the second, cycle of Renografin gradient centrifugation, the cells were passed through microfilter glass filters which facilitated the removal of host components. The integrity of morphologically different cell variants was maintained during purification procedures by suspending highly purified C. burnetii in phosphate-buffered saline-sucrose solutions. C. burnetii, phases I and II, obtained by these methods appeared to be free from host cell components by serological methods while retaining morphological integrity and infectivity for yolk sacs and experimental animals. Average yields of C. burnetii were 2.83, 1.5, and 0.84 mg (dry weight) per yolk sac of the Ohio strain (phase I), 9 Mile strain (phase I), and 9 Mile strain (phase II), respectively. Recovery of phase I cells averaged about 70%, whereas the recovery of phage II cells was approximately 40%. The temporal sequence of phase I and II antibody response was demonstrated in infected and vaccinated animals. Also, no antibody response in mice and guinea pigs to yolk sac antigens was detectable after two injections of vaccine or viable cells. Importantly, this is the first report of the separation of viable phase II cells of C. burnetii free of host components.

Animals↗
PubMed1981

Developmental cycle of Coxiella burnetii: structure and morphogenesis of vegetative and sporogenic differentiations.

Coxiella burnetii is a gram-variable obligate intracellular bacterium which carries out its development cycle in the phagolysosome of eucaryotic cells. Ultrastructural analysis of C. burnetii, in situ and after Renografin purification, by transmission electron microscopy of lead-stained thin sections has revealed extreme pleomorphism as demonstrated by two morphological cell types, a large cell variant (LCV) and a small cell variant (SCV). Potassium permanganate staining of purified rickettsiae revealed a number of differences in the internal structures of the cell variants. (i) The outer membrane of the sCV and LCV were comparable; however, the underlying dense layer of the SCV was much wider and more prominent than that of the LCV. The periplasmic space of the SCV was not readily visualized, whereas the periplasmic space of the LCV was apparent and resembled that of other gram-negative bacteria. (ii) Complex internal membranous intrusions which appeared to originate from the cytoplasmic membrane were observed in the SCV. The LCV did not harbor an extensive membranous system. (iii) Some LCVs contained a dense body in the periplasmic space. This endogenous structure appeared to arise in one pole of the LCV as an electrondense "cap" formation with the progressive development of a dense body approximately 130 to 170 nm in diameter which was eventually surrounded by a coat of at least four layers. Our observations suggest that the morphogenesis of C. burnetii is comparable, although not identical, to cellular differentiation of endospore formation. A developmental cycle consisting of vegetative and sporogenic differentiation is proposed.

Cell Membrane↗
PubMed1980

Properties of selected rickettsiae of the spotted fever group.

Eight strains of spotted fever group rickettsiae were studied to gain insight into the extent of variation of their properties. Two standard strains of Rickettsia rickettsii and one strain of Rickettsia conorii were included among the eight for comparison. The molar percentage of guanine plus cytosine for each strain did not differ significantly from that for R. rickettsii, 32.6 +/- 0.7%. Two strains caused extended fever in guinea pigs, one strain caused fever of short duration, and the other strains induced little or no fever. Polyacrylamide gel electrophoresis of the detergent-solubilized rickettsial proteins indicated that the protein content of all strains, except the two strains of R. rickettsii, were different, particularly in the molecular weight range of 40,000 to 60,000. Virulent strains produced large clear plaques in Vero cells monolayers; the strains of low virulence generally produced smaller or more turbid, or both, plaques. On the basis of agglutination reactions with rabbit antisera, the eight strains were placed into five serotypes. These results indicate considerable heterogeneity in properties of spotted fever group rickettsiae in the United States.

Animals↗
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↗
PubMed1975

Fine structural changes at Entamoeba histolytica rabbit kidney cell (RK 13) interface.

When bacteria-free trophozoites of Entamoeba histolytica were added to a monolayer of rabbit kidney cells, cellular injury occurred at the sites of contact. Changes appeared within the cell cytoplasm before there was any generalized cell membrane damage. At some points of contact there was apparent fusion of amoebic and cell cytoplasm. Electron-dense bodies, here interpreted as liposomes, were present in the amoebic cytoplasm and beneath the surface membrane. No surface lysosomes were seen. Various modes of cell damage and enzyme transfer from amoeba to cell are suggested, together with the possibility that cytopathic amoebae are infected with virus particles.

Amebiasis↗
PubMedDate not supplied

Maternal transmission of duck hepatitis B virus in pedigree Pekin ducks.

A 14-month old female Pekin duck experimentally infected as an embryo with duck hepatitis B virus via the amniotic route has been a chronic carrier of duck hepatitis B virus with very high (P/N) values of DNA polymerase activity since hatching. All the progeny were, on evaluation for congenital infection, found to be duck hepatitis B virus positive by endogenous DNA polymerase reaction and electron microscopy. These offspring remained persistently viremic throughout the study. Maternal transmission therefore bred true to a total of 49 offspring--24 ducklings (less than 24 hr old) and 25 ducks--studied. Six of these 25 ducks matched for age and sex and bled weekly for 6 weeks exhibited fluctuating plasma levels of DNA polymerase activity. Higher DNA polymerase activity was detected in newly hatched ducklings than in older viremic ducks. This observation was corroborated with the results of electron microscopic examination of thin sections of liver. Duck hepatitis B virus particles, located within vesicles of rough endoplasmic reticulum in the cytoplasm of hepatocytes, were more abundant, and therefore more readily observed, in ducklings than in older ducks.

Animals↗