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Biomedical subjects

T Ericson

Publications and source records attributed to T Ericson.

At least 55 records · Page 3Linked to original sources
PubMed1982

Ellipsometric studies of film formation on tooth enamel and hydrophilic silicon surfaces.

The uptake of salivary substances onto hydrophilic negatively charged surfaces of silicon or onto enamel surfaces was studied in vitro with ellipsometry. There was a rapid initial uptake of substances followed by a slow but continuous uptake probably of other substances, which could be removed from saliva by absorption with a S. mutans serotype c strain. the kinetics for the uptake onto enamel and silicon surfaces and the thicknesses of the layers were similar. The combination of ellipsometry and silicon surfaces is suggested as a model for obtaining increased information on dental pellicle formation.

Chemical Phenomena↗
PubMed1981

Saliva-induced aggregation of micro-organisms from skin, tooth surfaces, oral mucosa, and rectum.

A total of 57 bacterial strains were isolated from tooth surfaces, oral mucosa, skin of the upper lip, and rectum of 3 persons. Identification of the strains indicated that each type of surface had a characteristic microflora. Aggregation of bacterial suspensions, induced by salivary agglutinins, was measured spectrophotometrically as the decrease in optical density (OD) by time. The aggregation curves for the oral strains followed a sigmoid pattern. The aggregation rates varied between individuals and strains. Most fecal strains showed an aggregation pattern which differed from that of the oral strains and was characterized by only a small, initial decrease in OD. The few strains, mainly Propionibacterium strains, collected from the skin of the upper lip did not aggregate. It appears from the data that several mechanisms are involved in the retention of bacteria to surfaces.

Adult↗
PubMed1981

An evaluation of the specificity of salivary agglutinins.

Four bacterial strains collected from tooth surface, oral buccal mucosa, skin of the upper lip, and rectum were used to evaluate the specificity of salivary agglutinins. A saliva sample was absorbed with each of the strains, and the remaining supernatants were tested for agglutinin activity against all strains. The effect of concanavalin A and pH on the S. mutans and S. mitior agglutinins was studied. The conclusion was drawn that the agglutinins for the S. mutans and S. mitior strains differed but that the S. mitior strain rested carried a receptor site for the S. mutans agglutinin without becoming agglutinated. The S. mutans agglutinin seems to have either unsubstituted mannopyranosyl or N-acetylated glucopyranosyl residues as structural components.

Agglutinins↗
PubMed1981

Effect of calcium on reactions between a salivary agglutinin and a serotype c strain of Streptococcus mutans.

Using a serotype c strain of Streptococcus mutans we found that the agglutinating activity could be quantitatively absorbed, and desorbed from the micro-organisms by a phosphate buffer. The desorbed agglutinin was found to be inactive in the absence of calcium. Calcium alone did not induce aggregation. At 0.1 mM calcium most of the activity was regained. Other cations could not substitute for calcium. On a molecular basis the ratio between calcium and agglutinin or bacteria is high, in the order of 10(7) and 10(4) respectively.

Absorption↗
PubMed1978

Actual caries development compared with expected caries activity.

In 18 schoolboys, 16 years old, the actual caries development during 1 year was compared with the expected caries activity which was predicted from evaluations of four selected tests: (1) the buffer capacity, (2) the titer of Streptococcus mutans in stimulated whole saliva, (3) clinical evaluation of rate of plaque formation, and (4) a quantitation of a salivary agglutinin reacting with a serotype c strain of S. mutans. According to previous experiences the estimated value for each factor was classified for each individual either as a negative (carries-provoking) or as a non-negative factor. The score of negative factors could thus vary between 0 and 4 for each individual. A good relationship was observed between the caries increment during 1 year and the sum of the scores from the tests representing expected caries activity. This observation indicates the possibility of selecting the most caries susceptible individuals in a population by using the four parameters. A selection can be made from two or three of the tests but then the degree of differentiation becomes lower. No parameter could singly be used as an indication of the potential caries activity in the individual test.

Adolescent↗
PubMed1975

The reaction of salivary substances with bacteria.

Reactions between selected strains of oral streptococci and saliva were studied spectrophotometrically. The curves of absorbance (700 nm) versus those of time were sigmoidal for aggregating saliva-bacteria mixtures. Whtn the logarithm of the ratio of the change in absorbance to the remaining absorbance was plotted against the reaction time, straight lines were obtained. At a fixed concentration of bacteria, the slope of these lines for a series of dilutions of a selected saliva sample was a parabolic function of the volume of saliva in the reaction mixtures. A model for the aggregation reaction was developed which explained the shape of these parabolic curves. The parameters of the model can be calculated from the experimental data and can be used to estimate the concentration of aggregation-inducing substances in undiluted saliva. A method for calculating the specific rate constant for the binding of free cells to aggregates was developed. This rate constant is a characteristic feature of a given aggregation reaction and can, in principle, be used to distinguish between aggregation-inducing substances of different molecular structures.

Humans↗