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Biomedical subjects

R A Cawson

Publications and source records attributed to R A Cawson.

At least 55 records · Page 3Linked to original sources
PubMed1980

Ultrastructural study of glycogen in Candida albicans.

Cultured blastospores of Candida albicans exhibit cytoplasmic granularity which obliterates the identification of its organelles. Abundant glycogen particles attribute to this phenomenon to a large extent.

Candida albicans↗
PubMed1979

Applications of xeroradiography in dentistry-a review.

Xeroradiography is the technique in which electrostatically charged plates sensitive to X-rays are used in diagnostic radiology in place of conventional film. There has however been anxiety that radiation dosage for xeroradiography may be at unacceptably high levels. James et al., however, in 1973 showed that by increasing the kilovoltage to at least 120 the exposure could be reduced by 60 per cent. Using higher kV lateral oblique jaw and lateral and anteroposterior skull xeroradiographs have been produced with lower radiation exposure than conventional film. Bony detail is much more sharply delineated on xeroradiographs and soft tissues are visible on the same picture without use of a grid or wedge filter. These features are of obvious advantage in cephalometrics and orthognathic surgery. Panoramic techniques are potentially the most useful way of applying xeroradiography. The combination of full jaw coverage with the sharp definition only possible at present with intra-oral radiographs would provide more information for the dentist, save time for the radiographer and reduce the dose to the patient. Excellent results have been obtained with autopsy specimens on machines which develop 90kVp, but optimal exposure for a normal adult requires a panoramic X-ray machine development 120 kVp. Xeroradiography has the advantage, therefore, of providing more detail of diagnostic value with lower radiation exposure to the patient. The process requires no silver, which is in increasingly short supply.

Humans↗
PubMed1979

The induction of germ tubes in Candida albicans by an intrinsic factor.

The formation of germ tubes in Candida albicans can be initiated by variations in the growth medium and in other environmental factors. Cell-to-cell interaction can also be an essential factor in cell morphogenesis. The crowding together of blastopores of some strains of C. albicans stimulates the development of germ tubes without the addition of extrinsic factors.

Candida albicans↗
PubMed1978

The surface layer of Candida albicans.

The surface of Candida albicans is covered by a mucus layer secreted by the cell. Excess mucus secretion accumulates between the cells, and contains protein, polysaccharides and secreted enzymes. In mature cultures dead cells are trapped in the mucus, and the accumulated mucus and cell debris facilitate the formation of plaque, and the penetration of C. albicans into infected host tissues.

Acid Phosphatase↗
PubMed1978

Septal ultrastructure in Candida albicans.

Fine structural studies on the septa of Candida albicans in vitro (when leading a saprophytic existence) and the organism in its invasive form (as a pathogen in oral candidosis) have shown that in the former the septum exhibits a unique central perforation resembling an aggregate of fine canaliculi connecting one cell to the other. In the invasive form the septum is non-perforated and appears as a solid structure. Septal ultrastructure is well characterised in many pathogenic fungi. Our observations on Candida albicans do not resemble any previous studies carried out on other deutromycetous fungi.

Candida albicans↗
PubMed1977

The advantages of xeroradiography for panoramic examination of the jaws and teeth.

Xeroradiography is an electrostatic imaging method which was significant advantages over conventional radiographic techniques. This article introduces the use of xeroradiography for panoramic examination of the jaws. The resultant images not only contain superior local contrast and detail when compared to conventional panoramic radiographs but also correlate well with histopathologic changes. The investigation indicates that xeroradiography is an important new diagnostic tool for detection of disease of the jaws and teeth.

Adolescent↗
PubMed1977

Phospholipase activity in Candida albicans.

Phospholipase A and lysophospholipase have been identified as the enzymes responsible for phospholipid hydrolysis by Candida albicans. The method used to identify and measure the activity of these enzymes is described, and the probable significance of phospholipase in the invasion of the epithelium by Candida albicans discussed.

Candida albicans↗
PubMed1976

Macromolecular syntheses during the cell cycles of yeast and hyphal phases of Candida albicans.

Synchronous cultures of yeast and hyphal phases of Candida albicans showed exponential increases in RNA content and stepwise exponential increases in DNA content. The periods of DNA synthesis in the two phases coincided with one another and with the budding peaks of the yeast phase. Hyphae grown in synchronous cultures also showed an exponential increase in length. The hyphal phase was therefore normal. Hyphal nuclear division occurred after hyphal DNA synthesis. Germination was a unique event for a hypha and unlike yeast bud formation, preceded the first period of DNA synthesis. The exponential increase in RNA and DNA in asynchronous cultures of hyphae in serum paralleled the exponential increase in the numbers of cells in asynchronous cultures of yeasts in defined media. Thus there are no factors in serum which inhibit the normal exponential growth of C. albicans.

Candida albicans↗
PubMed1976

Oral changes in Crohn's disease.

Oral lesions in patients with Crohn's disease may be characteristic granulomatous lesions, secondary results of deficiency conditions, or coincidental lesions. Thorough investigations are necessary to rule out involvement of the gut in the disease process. If results fail to substantiate a diagnosis of Crohn's disease, regular follow-up examinations are necessary to detect possible later development of the disorder.

Adolescent↗
PubMed1976

Depression of bursal follicle formation by Candida albicans infections.

Sub-lethal i.v. inoculations of Candida albicans into 12-day-old chick embryos have been shown to cause a depression of follicle formation in the bursa of Fabricius. This depression occurred in the absence of any infection in the bursa, although candidal encephalitis was a frequent manifestation of the disseminated infection. A similar depression of bursal follicle formation was caused by the administration of viable C. albicans on to the embryonic chorio-allantoic membrane, in the absence of any disseminated infection. Non-viable extracts of disrupted C. albicans administered on to the chorioallantoic membrane also caused a depression of bursal follicle formation. This immunodeficiency produced by an endotoxin-like principle at a susceptible stage in the development of the chick has been considered in terms of human immunological development and the neonatal occurrence of C. albicans.

Allantois↗