Biomedical subjects

G Rölla

Publications and source records attributed to G Rölla.

At least 19 recordsLinked to original sources

PubMed2004

Insoluble zinc, cupric and tin pyrophosphates inhibit the formation of volatile sulphur compounds.

Oral malodour is mainly a result of the production of volatile sulphur compounds (VSC). The present study was concerned with investigating the anti-VSC effect of insoluble pyrophosphates (PP) of zinc, copper(II) and tin(II). The hypothesis to be tested was that the sulphide anions produced when VSC are solubilized in water have a higher affinity for the respective metal ions than the PP anion. The anti-VSC effects of insoluble PP were compared with the corresponding soluble metal salts using three in vitro methods: saliva putrefaction; dialysis of a suspension of PP and saliva against water; and analysis of water containing hydrogen sulphide and methyl mercaptan gases, and gases in the headspace. The levels of VSC were analysed by gas chromatography in the first and third methods, and released metal ions were analysed by atomic absorption spectroscopy in the second. The results showed that: the insoluble metal PP inhibited VSC formation in saliva by 99-100%; under dialysis, only minute amounts of metal ions are released from the combination of PP and saliva; and the PP lost their metal cations in water containing dissolved gases and inhibited VSC formation. Hence, the results support the experimental hypothesis. Sulphide ions are obviously very strong ligands for these metal ions.

Adult↗

PubMed2003

Combined effect of zinc ions and cationic antibacterial agents on intraoral volatile sulphur compounds (VSC).

OBJECTIVE: Volatile sulphur compounds (VSC) are major components of oral malodour. As both zinc ions and cationic antibacterial agents inhibit the formation of oral VSC, this study aimed to determine whether these agents combined have synergistic anti-VSC actions. METHODS: Baseline oral VSC measurements of mouth air from 10 volunteers following cysteine rinsing (6mM, pH 7.2) were obtained using gas chromatography (GC). Subjects rinsed for 1 min with 10ml of the test solutions, 0.3% zinc acetate (Zn), 0.025% chlorhexidine (CHX), 0.025% cetyl pyridinium (CPC), and the combinations Zn+CHX and Zn+CPC. Cysteine rinses were repeated at 1h, 2h and 3h and VSC measurements recorded. Three subjects rinsed with the Zn+CHX combination and fasted for 9h, undergoing cysteine rinses and VSC measurements at 3h intervals. 10 microl of the test solutions were also added to 1ml aliquots of human whole saliva (n=8). Following incubation at 37 degrees C for 24h VSC levels in the saliva headspace were measured by GC. Inhibition of VSC formation and the fractional inhibitory index indicating synergy were calculated. RESULTS: Zn+CHX mouthrinse had a synergistic anti-VSC effect, and was effective for at least 9h. Zn+CPC mouthrinse was less effective. Both combinations showed a synergistic inhibiting effect in-vitro. CONCLUSIONS: Synergy between Zn and the antibacterial agents confirms different mechanisms of operation.

Adult↗

PubMed2002

The significance of the source of zinc and its anti-VSC effect.

UNLABELLED: The anti-VSC (volatile sulphur compounds) effect of zinc is known to be associated with free zinc ions. OBJECTIVE: To examine whether zinc salts with low stability constants were more suitable as sources of zinc in zinc lozenges than zinc salts with high stability constants. The former provide free zinc ions upon dissolution in water, whereas the latter provide few such ions. DESIGN AND PARTICIPANTS: Identical lozenges were produced which contained either zinc acetate, zinc gluconate (low stability constants), zinc citrate or amino-acid chelated zinc (extremely high stability constants). All the lozenges contained 0.1 per cent of zinc. A test panel of 10 volunteers used the different lozenges randomly. VSC were measured by GC. RESULTS AND CONCLUSION: The lozenge with the highest stability constant was as effective as those with very low stability constants. The anti-VSC effect was thus not related to this constant. These findings may be explained by the possibility that alternative ligands with stronger affinity for zinc than the original ligands in the lozenges may be present in the oral cavity. An in vitro experiment indicated that the sulphide ion (S2-) may be such a ligand.

Adult↗

PubMed2001

Effects of metal salts on the oral production of volatile sulfur-containing compounds (VSC).

BACKGROUND/AIM: Halitosis, mainly caused by bacteria located on the posterior dorsum of the tongue and in periodontal pockets, is due to formation of volatile sulfur compounds (VSC). The hypothesis to be tested was that the affinity of a metal for sulfur determines its anti-VSC activity. METHOD: Clinical tests were carried out on 12 subjects who rinsed with cysteine to induce halitosis (baseline) before rinsing with 7.34 mM ZnCl2, SnF2 and CuCl2. Mouth air VSC analyses were repeated following cysteine rinses at 1 h, 2 h and 3 h using a gas chromatograph. In vitro experiments tested toxic metals Hg2+, Pb2+ and Cd2+. 10-microl aliquots of metal salts were added to 1-ml aliquots of human whole saliva from 30 subjects. Samples were incubated overnight at 37oC and saliva headspace was analyzed for VSC in a gas chromatograph. CLINICAL RESULTS: Cu2+>Sn2+>Zn2+ (supports hypothesis). Zn2+ had significantly less anti-VSC effect compared with Cu2+ and Sn2+ at 1, 2 and 3 h. In vitro results indicated that Hg2+, Cu2+ and Cd2+ had close to 100% anti-VSC effect, and that Pb2+ was less effective and Cd2+ more effective than expected in inhibiting VSC. CONCLUSIONS: Apart from Hg2+ and Cu2+, the metals had a significantly greater effect on H2S than on CH3SH. Cu2+ and Hg2+ have well-known antibacterial activity and may presumably also operate by this mechanism.

Adult↗

PubMed1999

Quantitative and qualitative analyses of human salivary micelle-like globules.

In the present study we examined the protein proportion and amino acid profile of the salivary micelle-like globules (SMGs) of human whole saliva and parotid saliva (HWS, HPS). Saliva and SMG samples from each subject (clarified HWS and HPS from 6 subjects, and unclarified HWS from 3 subjects) were analysed for amino acids using standard acid hydrolysis procedures. HPS, clarified HWS and the respective supernatant samples (remaining after removal of the SMGs) were also measured for protein using the micro-Kjeldahl method. SMGs from clarified and unclarified HWS made up 4.7% and 19.7%, respectively, of the total salivary protein based on amino acid analyses. With the micro-Kjeldahl method SMGs from clarified HWS made up 7.3% of the total saliva protein. SMGs isolated from HPS were found in only small amounts. The amino acid profile for the SMGs was strikingly similar to that known for the 2-h pellicle, and differed significantly from HWS or HPS. The results support previous morphological studies indicating that the SMGs represent a major component of the newly formed pellicle.

Adult↗

PubMed1997

Does the nature of the solvent affect the anti-inflammatory capacity of triclosan? An experimental study.

The anti-inflammatory properties of triclosan have been revealed in several recent studies, including an effect on histamine-induced inflammation. In other studies, the nature of the solvent has been shown to be of importance for the plaque inhibiting as well as the antibacterial potential of triclosan. This study was aimed at examining whether the nature of the solvent also may influence the anti-inflammatory capacity of triclosan and further to study a possible dose/ response relationship. The study was performed as 3 separate, double-blind experiments, comprising 10, 11 and 12 healthy females. In all 3 experiments, 5 sites on the lower part of the back of the volunteers were intradermally exposed to one drop of 1% histamine dihydrochloride for 15 min. The size of the resulting wheals was recorded before and after 40 min of triclosan treatment. In experiment 1, 4 different concentrations of triclosan in 2-fold dilutions in absolute alcohol (0.125%-1%) were applied on the histamine-induced wheals. In experiments 2 and 3, 4 different solutions containing 0.5% triclosan and a saline solution as negative control were used. The solvents in experiment 2 were as follows: (1) absolute alcohol (positive control), (2) propylene glycol (PG), (3) polyethylene glycol (PEG), (4) olive oil, and in experiment 3: (1) absolute alcohol (positive control), (2) Tween 80, (3) sodium carbonate, (4) soy oil. The results showed a dose/ response effect of triclosan and further that the solvent may be of importance for its anti-inflammatory potential.

Adult↗

PubMed1997

Fractionation of salivary micelle-like structures by gel chromatography.

Globular structures have been demonstrated in human parotid saliva by transmission electron microscopy and photon correlation spectroscopy. The aim of this study was to fractionate these salivary globular structures for analytical and preparative purposes using a gel-filtration material capable of separating spherical particles up to 300-400 nm in diameter. Freshly obtained parotid saliva was applied to a Sephacryl S-1000 column. Peak fractions were collected and prepared for transmission electron microscopy (TEM) or for amino acid analysis. Bovine milk was included as the casein micelles by TEM appear to be similar to the salivary aggregates and their elution profiles are known. The salivary globular structures were eluted in one major peak. TEM of negatively stained samples from the peak fractions demonstrated globular protein aggregates consistent with the salivary structures in parotid saliva. Amino acid analysis showed characteristic amino acid profiles with unusual high levels of proline, 40-45%. The casein micelles were eluted in one major peak and separated from the whey proteins. This study indicates that the salivary globular structures can be isolated by gel chromatography. The amino acid analysis indicates that proline-rich proteins may be an important fraction of the salivary globular structures.

Adult↗

PubMed1997

The influence of triclosan, zinc or propylene glycol on oral mucosa exposed to sodium lauryl sulphate.

Previous studies on triclosan treatment of skin exposed to sodium lauryl sulphate (SLS) indicated a protective rôle of zinc and an irritant effect of propylene glycol (PG). The aim was hence to examine whether zinc or PG also may affect SLS-induced oral mucosal reactions, and also to test the influence of zinc in combination with triclosan. 15 healthy dental students participated in this double-blind crossover study performed in 2 experimental series. They were rinsing 2x daily with solutions containing (A) 1.5% SLS, (B) 1.5% SLS/0.5% zinc citrate and (C) 1.5% SLS/PG (1:8) in experiment 1, and (D) 1.5% SLS/0.15% triclosan/0.3% zinc citrate and (E) 1.5% SLS/0.15% triclosan in experiment 2. Clinical evaluation by 2 examiners of degree of erythema and oral mucosal desquamations was then performed. The critical micellar concentration was also determined. SLS and SLS/PG, which were not different in effect, evoked significantly more erythematous reactions than SLS/Tri/Zn. This solution was numerically but not statistically better than SLS/Tri, and the latter also did lead to significantly less erythema than SLS/PG. In conclusion, the present study revealed no irritation of the oral mucosa due to PG, whereas a protective effect of zinc as well as the anti-inflammatory effect of triclosan were confirmed.

Adult↗

PubMed1997

Zeta potentials of human enamel and hydroxyapatite as measured by the Coulter DELSA 440.

The zeta potential of human enamel is of physiological importance for interactions between enamel surfaces and the surrounding aqueous medium of saliva. The zeta potentials of both enamel and hydroxyapatite (HA) have been examined previously by various techniques. In this study, we examined the zeta potential of human enamel and HA using the Coulter DELSA 440, which, by a laser, makes independent Doppler shift measurements of moving particles in an electric field at 4 different angles, providing advantages over previous techniques. The enamel and HA particles were suspended directly in different phosphate buffers, or first incubated for 2 hrs in parotid (PS) or whole saliva (HWS) and then suspended in the same buffers. The enamel and HA particles exhibited an overall net surface potential of -15 to -30 mV, depending on the buffer content. Incubation in PS and HWS gave less negative potentials of -8 to -14 mV. In our previous studies, the salivary micelle-like structures (SMSs), seen in TEM of parotid saliva, were observed to have a zeta potential of -9 mV (Rykke et al., 1996). The zeta potential determinations in this study support the concept of an adsorption of mostly SMSs to the enamel surfaces, with a change of the zeta potential of the enamel and HA toward that of the SMSs.

Adsorption↗

PubMed1996

Triclosan reduces prostaglandin biosynthesis in human gingival fibroblasts challenged with interleukin-1 in vitro.

The effect of the toothpaste ingredient triclosan (2,4,4'-trichloro-2'-hydroxyldiphenyl ether) on the prostaglandins biosynthesis in human gingival fibroblasts challenged with interleukin-1beta (IL-1beta) or tumor necrosis factor alpha (TNFalpha) was studied in vitro. When gingival fibroblasts were treated simultaneously with triclosan and IL-1beta, the stimulatory effect of IL-1beta on prostaglandin E2 (PGE2) and PGI2 formation was reduced in a dose-dependent manner by triclosan. Triclosan also reduced the PGE2 formation induced by TNFalpha. Furthermore, the capacity of IL-1beta to induce release of [3H] arachidonic acid from prelabelled gingival fibroblasts was reduced in the presence of triclosan. Addition of exogenous unlabelled arachidonic acid (AA) to the cells resulted in enhanced PGE2 formation which was reduced by triclosan. The upregulation of the metabolism of AA to PGE2 induced by IL-1beta, was markedly reduced in the presence of triclosan. The study indicates that the stimulatory effect of IL-1beta on prostanoid formation (PGE2, PGI2) in human gingival fibroblasts was diminished in the presence of triclosan partly at the level of phospholipase A2 and partly at the level of cyclooxygenase. The present data that triclosan, in vitro, inhibits the production of inflammatory mediators such as prostaglandins suggests that this can be an aspect of its clinical effect on gingivitis, in addition to its antibacterial effect.

Adult↗

PubMed1995

Triclosan inhibits histamine-induced inflammation in human skin.

Previous studies indicate that triclosan reduces the pain and other symptoms after chemically-induced inflammation in the oral mucosa and skin when sodium lauryl sulfate (SLS) is used as an irritant. The aim of the present study was to examine whether triclosan has an effect on the inflammation in human skin caused by intradermal administration of histamine. 9 female volunteers participated in a double-blind study, and skin patch tests were performed in 2 series. In the 1st, the skin was pre-treated for 1 h with triclosan before the histamine was applied. In the 2nd, the histamine reaction was elicited first and triclosan applied subsequently. The effect of triclosan on the weals formed in the skin after histamine application was measured. It was found that triclosan reduced the size of the weals markedly when triclosan was applied after the weals were formed, and that pre-treatment of the skin had only a slight effect. It is assumed that triclosan has an effect on the cascade reactions of inflammation elicited by histamine. 2 other phenols tested in the same study had similar effects.

Administration, Cutaneous↗

PubMed1995

Triclosan reduces the clinical symptoms of the allergic patch test reaction (APR) elicited with 1% nickel sulphate in sensitised patients.

It has previously been shown that triclosan reduces the clinical skin reactions caused by sodium lauryl sulphate (SLS) in an irritant patch test reaction (IPR) model. Furthermore, triclosan reduces the inflammatory reactions on skin after subcutaneous injection of histamine. The aim of the present study was to examine whether triclosan reduces the clinical symptoms on skin after exposure to nickel in an allergic patch test reaction (APR) model. 1% nickel sulphate was used for APR in 10 nickel-allergic females. The results showed that application of triclosan on skin reduced the APR symptoms from nickel in sensitised patients significantly (p < 0.05) compared to the saline and alcohol solutions. It is suggested that inflammatory mediators produced by the sensitised lymphocytes are inhibited by triclosan.

Allergens↗

PubMed1995

Effects of triclosan on the rat phrenic nerve-diaphragm preparation.

It has been reported that the lipid soluble, anti-inflammatory drug triclosan, which is currently used in toothpastes and mouthrinses, may reduce pain. This may be an aspect of the anti-inflammatory effect of triclosan, which probably reduces the production of prostaglandin PGE2. However, triclosan may also exhibit a direct analgesic effect through an effect on excitable membranes. The aim of the present study was to examine the possible effect of triclosan on the nerve action potential, on the neuromuscular transmission and on the excitation-contraction coupling of skeletal muscle. Phrenic nerve-hemidiaphragm preparations, as well as isolated phrenic nerves, were dissected from Wistar albino rats and mounted by standard methods in Tyrode solution. Both during indirect and direct stimulation, the preparations were irreversibly inhibited by triclosan at concentrations higher than 5.0 x 10(-6)M. At low concentrations, the inhibition of the twitches during indirect stimulation and of the compound action potential was probably caused by a threshold increase for excitation of the phrenic nerve. At high concentrations, an additional inhibitory effect at the neuromuscular junction was disclosed. The directly stimulated preparation was also probably inhibited by an increase of the threshold for initiation of the muscle action potentials. In addition, a reduced KCl contracture and an acceleration of the caffeine contracture indicated an interaction with the sarcolemma. These results suggest that the analgesic effect of triclosan may be due to a direct interaction with excitable membranes.

Action Potentials↗

PubMed1994

Dental plaque inhibition by a combination of triclosan and polydimethylsiloxane (silicone oil).

It has previously been shown that a toothpaste which contains triclosan and polydimethylsiloxane (silicone oil) improved gingival health in a test panel with established gingivitis more markedly than usually observed when testing commercial triclosan-containing toothpastes. In the present study the mode of action of combinations of silicone oil and triclosan was investigated. An in vitro experiment showed that triclosan was retained in a thin layer of silicone oil on the inner surfaces of test tubes that had been treated with the combination of triclosan and silicone oil. This triclosan was slowly released and inhibited the growth of bacteria in the test tubes. Silicone oil alone and in combination with triclosan was able to inhibit polysaccharide adhesion to the test tubes in the presence of a strain of Streptococcus sobrinus and a sucrose-containing medium. Corresponding in vivo experiments showed similar results; teeth topically treated with silicone oil and triclosan showed a marked plaque reduction, and those treated with silicone oil alone showed a moderate reduction, as compared with a placebo. The silicone oil plus 0.3% triclosan combination inhibited plaque formation also on proximal surfaces. It appears likely that this combination provides a reservoir of triclosan in the thin layer of silicone oil which binds strongly to teeth because of its low surface tension. Triclosan is then slowly released into saliva because of its low solubility in this fluid.

Adult↗

PubMed1994

Triclosan-containing mouthwashes--does the nature of the solvent influence their clinical effect?

The effect of triclosan on plaque inhibition was studied with various solvents. Eight subjects used the solutions as mouthwashes twice daily for 4 days while refraining from any other form of oral hygiene. Bacteriologic tests were also done with the same solutions. The study showed that the nature of the substance used to dissolve triclosan may be of clinical significance. Solutions of triclosan in polyethylene glycol, glycerol, or 3% sodium lauryl sulfate (SLS) alone showed marked antiplaque effect. (The first two solutions both contained 1.5% SLS). However, triclosan dissolved in Tween 80 had only a negligible clinical effect. In vitro experiment showed that antibacterial tests did not correlate well with clinical data. It is proposed that the nature of the micelles of the detergents which are used to dissolve triclosan is of significant importance. Strongly charged micelles such as SLS show clinical effect, whereas less charged micelles of SLS/Tween 80 or uncharged micelles of Tween 80 alone appear not to have this effect.

Adult↗

PubMed1994

Effect of a combined chlorhexidine and NaF mouthrinse: an in vivo human caries model study.

Chlorhexidine (CHX) is probably the most widely used and the most potent chemical plaque inhibitory agent, whereas fluoride (F-) is the only truly accepted anticaries agent available at present. As they have discrete mechanisms of action, a combination effect of these agents on human dental caries may exist. The inhibitory effect of CHX on the formation of, and acid production in, plaque may reduce a relatively extreme cariogenic challenge sufficiently for it to be overcome by the local F- concentrations achieved by brushing or rinses. The aim of this study was to evaluate the possible caries inhibitory effect of combining 2.2 mM CHX mouthrinses used twice daily with daily 11.9 mM NaF rinses in an in vivo human caries model using plaque-retaining bands on premolars scheduled for extraction. Nine subjects (a total of 28 teeth) were fitted with the bands for 4 wk. Saliva and plaque samples were collected before and after the study period for bacterial cultures, and the tooth surfaces were analyzed by microradiography after careful tooth extractions. The combination of CHX and F- rinses resulted in enamel mineral loss only slightly higher than that observed in "sound" enamel and clearly less than with F- rinses alone. Both total plaque bacteria and Streptococcus mutans were reduced by CHX rinses, confirming the discrete mechanisms of action.

Adolescent↗

PubMed1994

Significance of choice of solvents for the clinical effect of triclosan-containing mouthrinses.

The aim of this study was to investigate the plaque-inhibiting effect of triclosan. It is known that triclosan and sodium lauryl sulfate (SLS) have a marked inhibitory effect. However, since SLS has a plaque-reducing effect in itself, the relative importance of triclosan and the surfactant is undecided. Twelve dental students participated in the trial, during which oral hygiene was suspended for 4-day periods when the different mouthrinses were used twice daily. The following mouthrinses were used: A, water (negative control); B, 0.2% chlorhexidine acetate (CHX) (positive control); C, 0.3% triclosan in water-free propylene glycol (PG); D, 0.3% triclosan with 1.5% SLS in PG; E, 0.15% triclosan in PG; F, 0.075% triclosan in PG; G, 0.3% triclosan in diluted PG (1:8 in water) with 1.5% SLS; and H, 0.3% triclosan in 0.5% sodium carbonate. The results showed that triclosan dissolved in the organic solvent PG had a significant plaque-inhibiting effect, whereas, dissolved in alkali, it had a negligible effect. The addition of SLS to PG somewhat reduced the antiplaque activity, and the aqueous solution of triclosan had markedly less effect. Lower concentrations of triclosan exhibited less clinical effect than higher concentrations. It can be concluded that triclosan alone, dissolved in a suitable solvent, has an antiplaque effect. The study confirmed the hypothesis that the nature of the detergent or organic solvent used to dissolve triclosan affects its clinical effect markedly.

Adult↗

PubMed1994

Does the presence of xylitol in a sorbitol-containing chewing gum affect the adaptation to sorbitol by dental plaque?

It is known that xylitol inhibits sorbitol metabolism in some bacteria in vitro. The effect of xylitol/sorbitol-containing chewing gum on sorbitol adaptation of dental plaque was therefore examined. Ten subjects used this chewing gum for 12 wk, and plaque was collected before (control plaque) and after (test plaque) the exposure to sorbitol/xylitol. The metabolism of sorbitol by the plaque was examined with 14C-labeled sorbitol, and the radioactive metabolites were detected by high-performance liquid chromatography (HPLC). A considerable individual variation in acid formation was found. The mean values of total acids in the test plaque increased, as compared with the control plaque. An adaptation of dental plaque to sorbitol thus occurred in spite of the presence of xylitol in the chewing gum. The concentration of acetic acid predominated over other acids in both the control and test plaques. The proportions of acids expressed in percentage of total acids differed only slightly. Thus, long-term use of xylitol/sorbitol-containing chewing gum did not eliminate the adaptation of dental plaque to sorbitol.

Acetates↗