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Biomedical subjects

J Rundegren

Publications and source records attributed to J Rundegren.

At least 19 recordsLinked to original sources
PubMed1995

Delmopinol interactions with cell walls of gram-negative and gram-positive oral bacteria.

The main purpose of the present study was to investigate the influence of delmopinol hydrochloride on the cell surface morphology of gram-negative and gram-positive bacterial cells by using transmission electron microscopy. A second purpose was to evaluate the extraction of cell wall material caused by delmopinol and the binding of radiolabelled delmopinol to the various strains. Fresh isolates and type strains of gram-negative rods associated with periodontal disease, Porphyromonas gingivalis, Prevotella intermedia, Actinobacillus actinomycetemcomitans, and strains of the gram-positive streptococci Streptococcus sanguis, Streptococcus mutans and Streptococcus salivarius, were exposed to 3.2 mM (0.1%) or 6.4 mM (0.2%) delmopinol hydrochloride from 1 to 90 min. For electron microscopy the cells were fixed and negatively contrast-stained. Treatment with 6.4 mM delmopinol for 1 min resulted in marked ultrastructural changes of cell wall components and the outer cell membrane of the 3 gram-negative species compared with control cells, whereas the gram-positive streptococci treated with delmopinol showed little or no morphologic alteration as compared with untreated cells. The result from the electron microscopy was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of proteins released from bacterial cells treated as for electron microscopy. More material was extracted from the gram-negative rods than from the gram-positive cocci. Significantly more delmopinol bound to the gram-negative rods than to the streptococci. It appears that the amphiphilic properties of delmopinol make gram-negative rods more vulnerable to delmopinol than gram-positive streptococci.

Aggregatibacter actinomycetemcomitans↗
PubMed1993

Agglutination of Streptococcus mutans serotype C cells but inhibition of Porphyromonas gingivalis autoaggregation by human lactoferrin.

The ability of various forms of human lactoferrin (LF) to agglutinate oral Streptococcus mutans, Strep. sobrinus, Strep. rattus, Strep. sanguis, Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans cells was studied spectrophotometrically. Fe3+ saturated LF was unable to agglutinate these bacteria, whereas iron-free LF (apo LF) effectively agglutinated Strep. mutans cells but not the other bacteria. The efficiency and rate of agglutination of Strep. mutans were somewhat lower with apo LF than with human whole saliva. However, secretory IgA, phosphate and whole saliva almost totally abolished the apo LF-mediated agglutination of Strep. mutans, suggesting binding to the same target sites on bacterial cell surfaces, or to each other. The presence of exogenous iron (Fe2+, Fe3+), lactoperoxidase or serum albumin did not affect the agglutination by apo LF. Low Ca2+ (50-100 microns) slightly enhanced the agglutination by apo LF but higher concentrations (0.5-1.0 mM) totally blocked the apo LF-mediated agglutination of Strep. mutans. Both saliva and apo LF significantly delayed the rapid autoaggregation of P. gingivalis cells. Aggregation of P. gingivalis is considered a potential virulence factor and a protective mechanism against the host's cellular defences in the gingival crevice. These findings show a novel, strain-specific antibacterial mechanism for LF against Strep. mutans and P. gingivalis and adds a new compound to the group of agglutinating proteins in human saliva.

Agglutination↗
PubMed1993

The binding of delmopinol and chlorhexidine to Streptococcus mutans and Actinobacillus actinomycetemcomitans strains with varying degrees of surface hydrophobicity.

This study evaluated the binding of chlorhexidine and the new surface-active anti-plaque agent delmopinol hydrochloride to Streptococcus mutans and Actinobacillus actinomycetemcomitans cells with various cell surface hydrophobicities. The influence of saliva concentration on the binding of these compounds was also investigated. The radiolabeled compounds were incubated with bacteria and the cells were recovered using a centrifugal filtering technique. Delmopinol had higher binding to the hydrophilic variant strains than to the hydrophobic parent strains; chlorhexidine had higher binding to hydrophobic than to hydrophilic A. actinomycetemcomitans strains and higher binding to hydrophilic than to hydrophobic S. mutans strains. The presence of salivary films decreased the binding of both compounds. Both delmopinol and chlorhexidine had stronger affinity to A. actinomycetemcomitans cells than to S. mutans cells. At equimolar concentrations, delmopinol had a lower binding to all strains tested than chlorhexidine. The high reversibility of the delmopinol binding might be related to a higher diffusion rate and solubility compared with that of chlorhexidine. The amphiphilicity of both molecules is an important feature in their retention to S. mutans and A. actinomycetemcomitans strains of varying hydrophobicities and could play an important role in the substantivity of delmopinol or chlorhexidine in the oral cavity.

Aggregatibacter actinomycetemcomitans↗
PubMed1993

In vitro interactions of delmopinol hydrochloride with salivary films adsorbed at solid/liquid interfaces.

Delmopinol hydrochloride is a highly surface active substance which has been shown to reduce the amount of plaque in vitro and in vivo and the level of gingivitis in vivo. Ellipsometry was used to evaluate the effect of delmopinol on films formed from whole, parotid and sublingual/submandibular saliva on solid surfaces. Hydrophilic plasma cleaned silica and methylated hydrophobic substrates were used. The adsorption processes of the salivary proteins and their interactions with delmopinol were monitored in situ with a Rudolph thin-film ellipsometer. The adsorption of delmopinol on bare substrates with out previous salivary adsorption was also investigated and the results indicate that delmopinol molecules were adsorbed on both hydrophilic and hydrophobic surfaces. When delmopinol interacted with the films formed from the different types of saliva an initial increase in the adsorbed amounts was observed in the majority of the cases indicating binding to the salivary pellicles and/or substrate surface. The noted increases were largest for the films adsorbed from whole and sublingual/submandibular saliva. After rinsing in the system, partial desorption of the salivary films took place. It is thus indicated that delmopinol binds to salivary proteins within the pellicles and alters the cohesive and adhesive properties of these films.

Dental Deposits↗
PubMed1992

Adsorption from salivary fractions at solid/liquid and air/liquid interfaces.

Ellipsometry and the drop-volume technique were used to study the interfacial behaviour of fractions obtained from unstimulated whole saliva. Fractionation was by gel filtration on a Superdex 200 Hiload column equilibrated with 10 mM potassium phosphate buffer, pH 6.8, containing 0.15 M NaCl. The fractions were reconstituted to have the same absorbance at 215 nm (estimated molecular-weight range, F1 greater than 760-460 K, F2 205-39 K, F3 14-4.5 K, F4 4.5-2.5 K, F5 1.5-0.85 K, F6 0.85 less than or equal to 0.5 K). The fractions were analysed for amino acid composition and studied by hydrophobic interaction chromatography on a Phenyl-Superose column. Fraction 3 contained the largest amounts of proline, followed by fractions 4 and 2. Fraction 3 showed the highest relative hydrophobicity. Ellipsometric measurements on negatively charged silica surfaces and methylated hydrophobic surfaces revealed that larger amounts of material adsorbed on hydrophobic than on hydrophilic surfaces. On hydrophilic surfaces the largest amounts were adsorbed from the high molecular-weight fraction 1. Fractions 4 and 6 did not give any adsorption at all on these surfaces. Fraction 3 gave the largest amounts adsorbed on the hydrophobic surfaces. Drop-volume measurements showed distinct differences in the ability of the salivary fractions to lower the surface tension. Fractions 2 and 3 showed the greatest reduction in surface tension. It was concluded that the adsorption behaviour of salivary proteins showed a wide variation among the different fractions and that it is influenced by the physicochemical characteristics of the interfaces present in the mouth.

Adsorption↗
PubMed1992

Effect of 4 days of mouth rinsing with delmopinol or chlorhexidine on the vitality of plaque bacteria.

Delmopinol is a new surface active anti-plaque agent that has demonstrated a low antimicrobial effect in vitro. By use of a vitality staining technique, the antimicrobial effect on bacteria in plaque samples was tested after rinsing with delmopinol or chlorhexidine. 6 healthy male subjects volunteered to rinse for 4 days using a double-blind cross-over study design with a wash-out period between the rinsing regimens. No oral hygiene measures were allowed during the test periods and each test period started with a professional tooth cleaning procedure 2 days before the start of rinsing to allow for plaque formation. Rinsing was performed with 0.2% delmopinol hydrochloride or 0.2% chlorhexidine digluconate 2 x a day. Small samples of plaque were collected from the buccal surfaces of premolars and 1st molars before the first rinse on day 1 and then before and 1, 2, 4, 7, and 24 h after the last rinse on the 4th day. The plaque samples were immediately stained with propidium iodide and fluorescein diacetate to visualize dead and vital microorganisms respectively. The vitality of the microflora was evaluated using a fluorescence microscope. The baseline vitality values were 91% for chlorhexidine and 86% for delmopinol. At day 4, the plaque vitality for chlorhexidine was approximately 40% up to 4 h and 50% at 7 h and 60% at 24 h after the last rinse. Corresponding values for plaque vitality after delmopinol rinsing were between 70 and 80% on all sampling occasions.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteria↗
PubMed1992

Effect of delmopinol on the viscosity of extracellular glucans produced by Streptococcus mutans.

The surfactant delmopinol, which is a new antiplaque agent with a low anti-microbial profile, was tested for its effects on the viscosity of bacterial extracellular glucans. Glucans were isolated from Streptococcus mutans broth supernatants incubated with 0.15 M sucrose in 50 mM sodium phosphate buffer at pH 6. The viscosity was measured in a shear rate range from 15 to 230 reciprocal seconds. The viscosity of the water-soluble glucan was found to be independent of shear rate whereas the water-insoluble glucan showed a strong shear thinning. The addition of delmopinol to preformed glucans did not affect the viscosity nor the shear rate dependence of the glucans. However, when present during synthesis of the polysaccharides, delmopinol was found to reduce the viscosity of both water-soluble and water-insoluble glucans by approximately 50% at the shear rates investigated. The reduction in viscosity for the water-soluble glucans was obtained at a delmopinol concentration of 0.32 mM (0.01%) and for the water-insoluble glucans at 3.2 mM delmopinol. The observed reduction of viscosity of glucans indicates that the in vivo stability of plaque matrix after delmopinol treatment would be lowered, which may lead to a reduction of plaque cohesion and thus facilitate mechanical plaque removal.

Glucans↗
PubMed1992

Effect of delmopinol on the cohesion of glucan-containing plaque formed by Streptococcus mutans in a flow cell system.

Glucan-containing plaque was formed by Streptococcus mutans adhering to saliva-coated glass slides in flow cells thermostated at 37 degrees C. The substrate was Brain Heart Infusion broth containing 1% sucrose and 10% sterile saliva. During the build-up of the plaque, which lasted for 29 h, the plaque was subjected to three two-minute exposures to either 0.1 mol/L sodium acetate buffer, pH 6.0, or the same buffer containing 6.4 mmol/L (0.2%) of the surface-active anti-plaque substance delmopinol hydro-chloride. The glass slides carrying the plaque were weighed, and plaques subjected to delmopinol treatment weighed only seven percent of the control plaques. The glass slides were then mounted in a beaker containing buffer, subjected to ultrasonication, and re-weighed. The delmopinol-treated plaques lost 59% of their wet weight upon sonication, while the controls lost only 19%. Control plaques having the same weight as delmopinol-treated plaques were not different from the control plaques grown for 29 h with regard to reduction of plaque weight after sonication. Transmission electron micrographs (TEM) showed a plaque dominated by globular or fibrillar matrix components in controls, while the delmopinol-treated plaque showed empty or unordered matrix areas between more densely packed cells. The TEM results were confirmed by scanning electron micrographs, which showed amorphous material associated with the bacterial cells in the control but not in the delmopinol-treated plaque. In conclusion, delmopinol reduced surface-associated glucan synthesis and lowered the cohesion of the plaque, indicating that glucan-containing plaque formed during repeated rinsings with delmopinol may be easier to remove by mechanical means than a non-treated plaque of this type.

Bacterial Adhesion↗
PubMed1992

In vitro interactions of anionic and cationic surfactants with salivary fractions on well-defined solid surfaces.

Ellipsometry was used to study the interaction of one anionic (SDS) and one cationic (CTAB) surfactant with films adsorbed from six different salivary fractions obtained after fractionation of whole unstimulated saliva on a Superdex 200 Hiload gel filtration column. Experiments were performed on both hydrophilic silica and hydrophobic methylated silica surfaces. The results of this study indicate that the adhesive and cohesive properties of the films adsorbed from the individual fractions were strongly dependent on the surface characteristics of the substrates and that the outcome of protein/surfactant interactions was dependent on factors such as protein composition, surfactant charge, and substrate characteristics. These interactions probably involve replacement of the adsorbed proteins by surfactants or protein/surfactant complex formation. The anionic surfactant seemed to be more efficient in removing adsorbed salivary proteins than the cationic one.

Adhesiveness↗
PubMed1991

Biological qualities of saliva sterilized by filtration or ethylene oxide treatment.

Stimulated whole saliva was centrifuged and sterilized either by filtration in the presence or absence of dithiothreitol (DTT) or by ethylene oxide treatment. Filtration was accomplished by 2 different techniques: conventional positive pressure filtration through prefilters and membranes with decreasing pore sizes and tangential flow microporous filtration. The sterile saliva samples were analyzed for enzyme activities of phosphatases, esterases, glucuronidase, and lysozyme. The samples were also tested by polyacrylamide electrophoresis, isoelectric focusing and for IgA concentration. Moreover, the samples were tested for support of bacterial growth of strains from the genera Actinomyces, Lactobacillus, Neisseria, Rothia and Streptococcus after the addition of glucose at a final concentration of 0.5%. The samples treated with ethylene oxide appeared to be more affected by this treatment than samples treated otherwise, as demonstrated by the electrophoretic analyses and analyses of enzyme activities. Ethylene oxide-treated saliva also was the least favorable saliva sample to support growth of bacteria. The positive pressure technique gave more rapid filtration than the tangential flow technique. DTT treatment of saliva facilitated filtration and, in contrast to ethylene oxide treatment, it affected the qualities of saliva only to a minor extent compared with the original saliva sample.

Dithiothreitol↗
PubMed1991

Effect of delmopinol on in vitro dental plaque formation, bacterial acid production and the number of microorganisms in human saliva.

This study investigated the effect of a surface active compound, delmopinol, on plaque formation and established plaque in vitro, on the bacterial acid production from glucose and on the total viable bacterial counts in saliva. The antimicrobial effect was compared with that of chlorhexidine. The plaque-inhibiting effect was evaluated in an artificial mouth system, and the effect on bacterial acid production was registered as a decrease of pH in bacterial suspensions with various concentrations of delmopinol. It was shown that delmopinol is able to prevent plaque formation, to dissolve established plaque in vitro, and that it has 5-125 times higher minimum inhibitory concentrations than chlorhexidine. Saliva samples collected 1 min after rinsing with delmopinol showed on differences in the total number of bacteria in saliva as compared with controls. It was also shown that the bacterial acid production from glucose was reduced successively with increasing concentrations of delmopinol. The results indicate that delmopinol might be as effective as chlorhexidine against plaque formation and that delmopinol is capable of penetrating established plaque, thus promoting a more effective mechanical cleansing.

Anti-Infective Agents, Local↗
PubMed1991

Effect of whole saliva on the rheologic behavior of extracellular water-soluble glucan produced by Streptococcus mutans.

The viscosity of mixtures of Streptococcus mutans water-soluble glucan and stimulated whole saliva or buffer was measured at pH 5, 6, 7, and 8. The viscosity was measured as a function of shear rate in the range 15 s-1-230 s-1. Though the centrifuged saliva had a viscosity close to that of water it increased the viscosity of the glucan up to 65% at pH 6 and 55% at pH 7 and at a shear rate of 20 s-1, indicating an interaction between saliva components and glucan that could be an important part of the cohesive forces of plaque matrix. The interaction between saliva and glucan was less pronounced at pH 5 and 8, which indicates a charge-dependent interaction. The viscosity increase at pH 6 and 7 was higher at low than at high shear rates, suggesting a higher contribution to plaque stability when weak as opposed to high mechanical forces are exerted on the plaque.

Buffers↗
PubMed1987

Separation of human IgA1 and IgA2 using jacalin-agarose chromatography.

A lectin isolated from the tropical jackfruit, jacalin, previously reported to precipitate human immunoglobulin A (IgA), and conjugated to agarose was used to separate the two subclasses of IgA from secretions. Jacalin-agarose binds specifically to the D-galactose moiety of IgA1 but not to IgA2 which has a different carbohydrate content and structure. IgA2 passed through the jacalin-agarose column and was collected in the void volume. IgA1 was eluted from the lectin by 0.8 M galactose. Of a representative diluted anti-alpha chain-purified colostral IgA preparation containing 50.2 micrograms IgA1 and 55.8 micrograms IgA2, 40.3 micrograms IgA1 (80.3% of the original) and 49.6 micrograms IgA2 (88.9%) was collected following jacalin-agarose chromatography. The jacalin-purified IgA1 fraction contained 8.0% IgA2 and the IgA2 fraction contained no IgA1. In addition, the IgA1 and IgA2 fractions had naturally occurring antibody activity to a normal oral bacterium. The method is easy, reproducible and specific and has many applications to mucosal immunological investigations.

Chromatography, Agarose↗
PubMed1987

Rate of plaque formation--some clinical and biochemical characteristics of "heavy" and "light" plaque formers.

The purpose of the present study was to give a clinical and biochemical characterization of two groups of individuals with different rates of plaque formation. From 133 individuals, 9 "heavy" and 10 "light" plaque formers were selected. The mean plaque index after 3 days of plaque accumulation, on buccal surfaces of premolars and first molars, was 2.6 for the "heavy" and 0.6 for the "light" plaque formers. The following variables were determined: periodontal status, DFS, dietary habits, salivary secretion rate and buffer effect, S. mutans and lactobacillus counts in saliva, salivary content of IgA, lactoferrin, lactoperoxidase and lysozyme, saliva-induced aggregation of certain oral streptococci, gel electrophoresis of saliva, amino acid composition of saliva and the acquired pellicle and retention depth of the dentogingival area. Comparing the two groups of plaque formers, statistically significant differences were found for the following three variables: parotid saliva-induced aggregation of a strain of S. sanguis, content of glutamic acid in the acquired pellicle and retention depth of the dentogingival area for maxillary premolars. Large variations for all studied variables were found, both within and between the groups. Several factors may be involved in plaque formation and none of the studied variables alone could explain the large difference in the amount of plaque formed after 3 days between the "heavy" and "light" plaque formers.

Adult↗
PubMed1987

Differentiation and interaction of secretory immunoglobulin A and a calcium-dependent parotid agglutinin for several bacterial strains.

Previous studies have suggested that both secretory immunoglobulin A (sIgA) and various nonimmunoglobulin salivary glycoproteins are capable of agglutinating a variety of bacteria. The present study was designed to compare the nature of the agglutinins for Streptococcus mutans and Salmonella typhimurium in parotid saliva and colostrum. S. mutans was aggregated by saliva and colostrum, whereas S. typhimurium was aggregated only by saliva as detected by a spectrophotometric method. The principal salivary agglutinin for both S. mutans and S. typhimurium was calcium dependent and could be desorbed in phosphate-buffered saline (pH 6.8). In contrast, the colostral agglutinin was calcium independent and not readily desorbed. The agglutinin activities of saliva and colostrum for S. mutans were additive, suggesting independent target sites on the bacterial surface. The agglutinin activity of colostrum was totally associated with sIgA as was suggested by blocking of the agglutinating activity with anti-alpha-chain serum and the absence of blocking with an antibody specific for salivary agglutinin. Interestingly, anti-alpha-chain serum removed all agglutinating activity from saliva, but not from the phosphate-buffered saline-desorbed agglutinin. Dialysis of parotid saliva against 0.1 M disodium EDTA eliminated the agglutinin blocking activity of anti-alpha-chain serum but not that of the antiagglutinin antibody. The ability of anti-alpha-chain serum to block agglutination of the EDTA-dialyzed saliva could be restored by the addition of calcium chloride, suggesting that sIgA and salivary agglutinin are associated through a calcium-mediated interaction. These results indicate that bacterial agglutinating activity of colostrum, as detected spectrophotometrically, is mediated by sIgA, and that of saliva is mainly dependent upon a calcium-dependent nonimmunoglobulin agglutinin. The agglutinating activities of sIgA and parotid agglutinin seem to be additive, and their calcium-dependent association may favor the enhancement of their respective activities.

Agglutination↗
PubMed1986

Calcium-dependent salivary agglutinin with reactivity to various oral bacterial species.

Human parotid agglutinins from three individuals were isolated by adsorption to and desorption from strains of Streptococcus mutans belonging to serotypes a, b, c, d, and e and strains of Lactobacillus casei, Actinomyces viscosus, and Streptococcus sanguis. The desorption was achieved by suspending centrifuged saliva-coated microorganisms in 10 mM phosphate buffer (pH 6.8) containing 0.154 M sodium chloride. After another centrifugation, agglutinin activity was recovered in the supernatants. The L. casei strain was not agglutinated by any of the agglutinin extracts or by saliva, but all the other strains were agglutinated to a variable extent. However, all strains, including the nonagglutinating L. casei strain, adsorbed and desorbed agglutinins active for other strains. The agglutinin extracts from S. mutans serotype c, S. sanguis, and A. viscosus were purified and characterized by electrophoretic and immunological techniques. The purified preparations were positively stained for protein and carbohydrate, and the molecular weights were estimated to be 440,000. All agglutinin extracts needed calcium in the range of 0.1 to 0.5 mM to be active, and for a single strain, all agglutinins gave the same degree of agglutination, indicating that the isolated agglutinins may be of the same molecular species, a hypothesis that was also confirmed by the preliminary characterization of the purified agglutinins. This type of agglutinin, which seems to exert its activity among various bacterial species, could be important in mediating bacterial coaggregation and thus may add to the effect of specific agglutinins in the clearance of bacteria from the human mouth.

Actinomyces↗
PubMed1985

Oral conditions in patients receiving long-term treatment with cyclic antidepressant drugs.

The function of the salivary glands, the caries situation, and pathological alterations of the oral mucosa of 32 patients, 20 dentulous and 12 edentulous, who had received long-term treatment (median 5.5 years) with cyclic antidepressant drugs were studied. Anamnestic information on dry mouth problems was recorded. Although a normal secretion rate for stimulated saliva was recorded in about 50% of the patients all but four complained over dry mouth. The majority of the patients had low values of salivary buffer capacity, high numbers of Streptococcus mutans and lactobacilli in the saliva, and poor oral hygiene. All except two patients had received dental care a year or less before the time of examination. Nevertheless 72% of the patients showed pathological alterations of their oral mucosa and 55% of the dentulous patients had new caries lesions. From an evaluation of the caries risk it was concluded that about half of the dentulous patients had a high caries risk, which seemed to be emphasized if combinations of psychotherapeutic drugs were used. It is recommended that patients receiving treatment with antidepressant drugs should be given an individually related dental prophylactic programme.

Adult↗