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T W Macfarlane

Publications and source records attributed to T W Macfarlane.

11 recordsLinked to original sources
PubMed1996

Comparison of polymerase chain reaction and culture methods for detection of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in subgingival plaque samples.

In this study, the major periodontal pathogens Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis were detected in subgingival plaque samples from patients with periodontal disease by polymerase chain reaction (PCR) and conventional culture methods. 170 plaque samples from 43 patients were analysed; A. actinomycetemcomitans and P. gingivalis were each detected in 40 (24%) of samples by PCR, whereas conventional culture methods detected A. actinomycetemcomitans and P. gingivalis in 25 (15%) and 18 (11%) of samples, respectively. The proportion of patients carrying A. actinomycetemcomitans in at least 1 sampled periodontal site was 17/43 (40%) by PCR and 13/43 (30%) by culture; for P. gingivalis this was 12/43 (28%) by PCR and 9/43 (21%) by culture. Only 5 samples, from 3 patients, harboured both A. actinomycetemcomitans and P. gingivalis. It is concluded that PCR is more accurate than conventional culture methods for identification of these periodontal pathogens in subgingival plaque samples and has a higher frequency of detection.

Aggregatibacter actinomycetemcomitans↗
PubMed1992

Taper: an important feature of Y-bifurcations in porcine renal arteries and human cerebral arteries.

The geometry of arterial bifurcations has been shown to alter fluid flow and the propagation of both pressure and flow waves. Here we provide a more complete description of the renal artery bifurcation geometry and show that the geometry of the bifurcation is more complex than was believed previously. The objective of this study was to quantify changes in cross-sectional luminal area in systemic arterial bifurcations using the method developed by Macfarlane [Ph.D. thesis, University of Western Ontario, Ontario (1985)] to study the geometry of human cerebral bifurcations. Porcine renal arterial bifurcations from seven young (6-14 weeks) and six old (greater than 52 weeks) animals were pressure-fixed (P = 140 mmHg) for 3 h with 10% formalin. Bifurcations were embedded in a block of frozen latex paint. Serial sections were cut at 20 microns (+/- 0.01 microns) using a sledge microtome while the block face was scanned with a video camera and the images were stored on a videotape. The luminal area was measured digitally upon playback. Bifurcations from the two age groups changed in cross-sectional area not only at the flow divider but also along the so-called straight regions. Proximal linear increases in cross-sectional area were observed proximal to the apex of the bifurcation in both young and old vessels, while linear luminal area decreases were measured in the daughter branches of both young and old porcine renals. Taper was defined as the change in luminal area per unit length of parent and daughter branches, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Secretor status, candidal carriage and candidal infection in patients with diabetes mellitus.

One hundred and nine patients with diabetes mellitus and 100 age-, sex- and denture-status-matched, non-diabetic individuals were investigated prospectively. Comparison was made of oral candidal carriage, clinical infection and inherited ability to secrete blood group antigens in saliva. Diabetic patients had a significantly higher prevalence of oral candidal carriage and infection (P less than 0.001) than non-diabetic individuals, but the candidal load between the 2 groups, was not significant. A comparable proportion of insulin-dependent, non-insulin dependent and control groups were secretors of blood group antigens, and there was no difference in the oral candidal carriage and infection rates between secretors and non-secretors.

ABO Blood-Group System↗
PubMed1987

Adhesion of Candida albicans to buccal epithelial cells exposed to chlorhexidine gluconate.

The adhesion of Candida albicans to buccal epithelial cells (BEC) exposed to chlorhexidine gluconate either in vivo or in vitro, was studied using BEC obtained from an adult and two children. There was a significant reduction in the adherence of yeasts to BEC collected immediately after an oral rinse of chlorhexidine. Also a significant positive correlation was noted (r = 0.99) between the time which elapsed after a chlorhexidine rinse and yeast adhesion to BEC. In-vitro exposure of BEC from both children and the adult to 0.2%, 0.02%, and 0.002% chlorhexidine, also reduced candidal adhesion to BEC.

Adhesiveness↗
PubMed1983

Computer-based video analysis of cerebral arterial geometry using the natural fluorescence of the arterial wall and contrast enhancement techniques.

The walls of mammalian arteries fluoresce with ultraviolet excitation in the wavelength range of 350-400 nm. We are using this property of natural fluorescence in conjunction with episcopic fluorescence microscopy, frozen section techniques, selective contrast enhancement, and a semi-automatic computer-based video analysis system to obtain dimensional data and 3-D coordinate maps of cerebral bifurcation geometry. The computer-video analysis system, comprised of commercially available video components, a Cromemco Z2D Computer, and electronic components built in our lab has a resolution of +/- 1/256 mm at full-screen magnification. Our technique is based upon measurement of the video image of the block face during frozen sectioning of cerebral bifurcations. This technique allows us to obtain axially symmetric coordinate maps of cerebral bifurcation geometry without the use of block markers. In addition to mapping lumenal and adventitial surfaces the system can be used to map atheromatous lesions and the outline of the internal elastic lamina. Our initial geometrical data suggest a linear increase of 50-60% in cross-sectional area in the apical region and widening of the apical region in the plane of the daughter branches.

Aged↗
PubMed1977

Nutritional deficiency in oral candidosis.

A retrospective study of 108 patients was carried out to investigate the possible relationship between infection of the mouth with Candida albicans and blood levels of iron, folic acid and vitamin B12. The patients were separated into two groups--those with hyperplastic and those with atrophic candidal lesions--and compared with separate control groups. Twenty-one patients had chronic hyperplastic candidosis and seven were iron deficient. Comparison with an age- and sex-matched control group showed the differences to be significant only at the p less than 0.1 level. Seven of the patients with hyperplastic lesions had folic acid deficiency and the difference between patients and controls was statistically significant (less than 0.05). However, no significant differences in iron or folic acid deficiency were noted between 87 patients with atrophic candidosis and 65 conttrols, and vitamin B12 deficiency was not statistically significant for either the hyperplastic or the atrophic group. It is concluded that deficiency of iron, folic acid or vitamin B12 alone does not promote growth of Candida albicans on the oral mucous membrane but that in some susceptible individuals, iron or folic deficiency may facilitate epithelial invasion by hyphae of Candida albicans.

Atrophy↗
PubMedDate not supplied

Shape changes at the apex of isolated human cerebral bifurcations with changes in transmural pressure.

The geometry of arterial bifurcations appears to play a significant role in the development of vascular disease. We have investigated the changes in bifurcation geometry with changes in distending pressure over the range 0.0 to 190.0 mm Hg. Five cerebral arterial bifurcations from human subjects were studied. The investigation focussed on the shape and on changes in the shape of the leading edge of the flow divider (internal apical curve). The curve outline at each transmural pressure increment (each 10.0 mm Hg) was photographed and digitized. The curves were plotted serially on an expanded scale. Visual comparison of the curves indicated flattening in the central region and broadening of the shoulders of the curves with increasing transmural pressure. Regression analysis using second order polynomials was used to obtain coefficients for equations defining short, overlapping segments of each curve. Twenty-four coordinates were used for each successive regression. Each curve was characterized by 85 to 100 digitized coordinates. The regression equations for each curve were used to calculate the curvature parameter, K, and the radius of curvature, R. Three of the five bifurcations demonstrated a negative correlation of K with increasing transmural pressure (p less than .001). This result supports the visual observation that the internal apical curve flattens with increasing transmural pressure. Flattening of the internal apical curve together with thinning of the arterial wall with increasing transmural pressure would contribute to a stress concentration at the apex of a cerebral bifurcation. This stress concentration would be more pronounced in the presence of a medial gap at the apex of the bifurcation. It is on or near this region of stress concentration that aneurysms develop.

Adult↗