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Biomedical subjects

L E Folke

Publications and source records attributed to L E Folke.

At least 19 recordsLinked to original sources

Composition and metabolic activity of dental plaque from healthy young and elderly individuals.

The composition and biochemical activities of 4- and 9-day-old plaque were studied in young and elderly subjects. Plaque accumulation tended to be greater in the older group. Levan hydrolase activity and the total number of recoverable, viable microorganisms were higher in plaque from younger subjects. Results suggest that the microbial composition of plaque is qualitatively different in younger and elderly subjects.

Adult

Aberrant blastogenic response to LPS in experimental gingivitis of elderly subjects.

The blastogenic response of peripheral blood leukocytes to lipopolysaccharide (LPS), phytohemagglutinin (PHA) and LPS/PHA mixtures was followed over a short course of experimental gingivitis in elderly subjects (65-81 years) who strictly avoided oral hygiene procedures for periods up to 9 d. The leukocytes responded poorly to LPS, PHA and to LPS/PHA combinations. The concomitant heightened sensitivity of the gingiva to dental plaque among the elderly subjects may relate to the altered leukocyte response in this age group.

Aged

Use of hydroxyapatite-coasted glass beads for preclinical testing of potential antiplaque agents.

Methods for rapid preclinical testing of antiplaque agents in vitro using hydroxyapatite (HT)-coated glass beads are described. The assays developed could reliably detect (i) prevention of growth in the culture fluid or on the HT surfaces, (ii) the effect of transient exposure of a bactericidal agent on the viability of cells in a preformed bacterial mat, (iii) reversible adsorption of a bactericidal agent on an HT surface, and (iv) the ability of an agent to inhibit adsorption of Streptococcus sanguis to an HT surface or to salivary proteins adsorbed to an HT surface.

Adsorption

Indirect blastogenesis of peripheral blood leukocytes in experimental gingivitis.

The blastogenic response of peripheral blood leukocytes to lipopolysaccharide (LPS) was followed over a short course of experimental gingivitis, developed in human volunteers who strictly avoided oral hygeine procedures for periods up to 9 days. Eleven young males initially received thorough dental prophylaxes and supervised oral hygeine until they acquired optimal gingival health. At this point, leukocytes (5 X 10(5)) incubated with 1.5 to 25 mug of LPS in serum-free media showed no response as measured by tritiated thymidine uptake. Coincubation of cells with LPS and phytohemagglutinin (PHA), however, caused synergistic enhancement of blastogenesis in every LPS-PHA dose combination tried. With progressive accumulation of dental plaque and the concomitant development of gingival inflammation, this synergistic response was lost and replaced, proportionately, by a direct response to LPS. The leukocyte response to PHA was marginally enhanced with gingivitis.

Adult

Elevation of a serum component in periodontal disease capable of modulating chemotactic infiltration.

Serum from dental patients was examined for its capacity to affect migration of polymorphonuclear leukocytes toward a complement-independent chemotactic factor, bacterial filtrate of Escherichia coli, (BF). Seven subjects with advanced periodontitis, documented with clinical measurements of pocket depth, loss of attachment, indices for gingival inflammation and oral hygiene, were paired with normal subjects of similar age and sex. This study shows that patients whose only apparent clinical symptom was severe periodontal inflammation harbor a heat-stable, serum component which neutralizes factors chemotactic for polymorphonuclear leukocytes. A role for this component in modulation of inflammatory infiltration is discussed.

Chemotaxis

Model system for studying colonization and growth of bacteria on a hydroxyapatite surface.

A model system for the study of bacterial colonization and growth on a hydroxyapatite (HT) surface is described. Hydroxyapatite was crystallized over the surface of porous glass beads. Chemical analysis of the product showed that the ratio of Ca2+/P042- was indistinguishable from that of commercial HT powder. X-ray diffraction analysis supported the conclusion that the product was HT. A system employing [14C]polyethylene glycol, which selectively adsorbs to the glass surface of the beads, was developed to determine the amount of glass surface covered by HT. Over 90% of the glass surface could be covered by our method. The product, HT beads, consisted of approximately 20% (dry weight) HT. The HT beads possess several properties which make them potentially useful for studying microbial adherence, growth, and interactions. These include: (i) chemical similarity to the tooth surface, (ii) large surface area, and (iii) high density. We also describe a method for direct measurement of the microbial mass of cells growing on beads. The method entails immobilizing a sample on a membrane filter (Millipore), staining it with amido black dye, and eluting the dye for spectrophotometric measurement. Streptococcus mutans served as the test organism. For free-growing bacteria the values measured with the filter assay were directly proportional to cell number, with a value of 1 mug of "protein" corresponding to about 1.5 X 10(6) colony-forming units, determined by viable count. For bacteria colonizing the beads, 1 mug of protein corresponded to about 2 X 10(7) colony-forming units on the beads during logarithmic growth. As the culture approached stationary phase, the efficiency of the assay decreased. These data indicate that multiple random samples, taken at a given time, are representative of the entire culture.

Bacteriological Techniques

A descriptive survey of signs and symptoms associated with the myofascial pain-dysfunction syndrome.

The signs and symptoms of 56 patients with myofascial pain-dysfunction syndrome were tabulated. Patients were classified by age, sex, education and professional background, frequency of complaints of pain, occlusal relationships, oral habits, and specific muscles that were tender on palpation. A coincidence of stress and tension and the onset of myofascial pain was observed. It is suggested that myofascial pain may be more common in women than in men. Muscle tenderness was associated particularly with the masseter, temporal, and lateral and medial pterygoid muscles.

Adolescent

The influence of dental plaques on the microvasculature of the oral mucous membrane.

This investigation was designed to explore the effect of plaque, obtained at different stages of accumulation, on the microvasculature of the hamster cheek pouch. Five groups of three dental students followed an oral hygiene abstinence program for 22 days. At day 2, 9, and 22, plaque was sampled from different anterior teeth, pooled and suspended in a reduced diluting fluid. Each of the three pooled plaque suspensions was then introduced into the right or left cheek pouche of five hamsters. Microvascular changes in the pouches were then observed and recorded photomicrographically until vascular reconstitution occurred. Plaque and gingival indices were taken, and the microbial composition of the plaque was determined according to gram-staining characteristics and morphology. The results indicate that the microvascular response was not a function of age and composition of plaque. This finding is based on the observation that 2-, 9-, and 22-day-old plaque induced similar microvascular damage which required approximately the same recovery period of 9 days to reconsitute normal microvascular function.

Adult

Chemotactic ability of dental plaque upon autologous or heterologous human polymorphonuclear leukocytes.

The chemotactic effect of pooled human plaque suspension, supernatant, and ultrafiltrate upon heterologous human PMNs was investigated using the Boyden chamber technique. It was observed that pooled plaque suspensions (20 mg/ml) were consistently chemotactic for heterologous human PMN cells. Whole plaque suspensions were most chemotactic, and the supernatant was approximately half as active, while the bacteria-free ultrafiltrate induced a negligible chemotactic response. Chemotactic assays of individual plaque suspensions were also performed. Twelve male subjects were paired according to age and PDI scores to assess whether the PMN cells of certain individuals responded differently to their autologous plaque. When comparing subjects with high or low PDI scores, there were no significant differences in the chemotactic responses. However, a trend of reduced chemotaxis was observed in most subjects with a high PDI. When the subjects were arbitrarily divided into groups with high and low plaque indices, a greater overall chemotactic response was generated by the higher plaque formers. The differences between the two groups, however, were not statistically significant.

Adult