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Biomedical subjects

S Twetman

Publications and source records attributed to S Twetman.

At least 73 records · Page 4Linked to original sources
PubMed1989

Effects of the thiazide diuretic bendroflumethiazide on salivary flow rate and composition.

Thiazide diuretics are among the first-line alternatives in the treatment of primary hypertension. The effects of thiazide treatment on salivary production are, however, little studied and the results so far available are not decisive. The aim of the present study was to evaluate and compare salivary flow rate and composition during treatment with the thiazide diuretic bendroflumethiazide in a low dose (2.5 mg o.d.) and placebo. The study was performed with a randomized, double-blind, cross-over design (2 x 2 wk) in 34 healthy volunteers. The treatment periods were separated by a wash-out period of 2 wk. Resting and stimulated whole saliva was sampled three times daily on scheduled days during the treatment periods. Flow rate was assessed for resting saliva, whereas flow rate, pH, buffer capacity, amount of total proteins and concentrations of sodium, potassium, calcium, phosphate and magnesium were measured for stimulated whole saliva. No effect of bendroflumethiazide on the resting salivary flow rate could be detected, while the stimulated flow rate was significantly reduced by about 10% during the thiazide treatment. The total sodium output was significantly decreased by approximately 30%, without any detectable change in total potassium output. All other variables of stimulated whole saliva studied were not different from placebo. It is concluded that treatment with bendroflumethiazide in a low dose significantly reduces the stimulated whole salivary flow rate and total sodium output in healthy volunteers.

Adolescent↗
PubMed1989

Oral mucous membrane lesions in children treated with bone marrow transplantation.

Oral mucous membrane lesions were studied in 54 children below 12 yr of age treated with allogeneic bone marrow transplantation mainly because of hematological malignancies. Sixty-two percent of the children exhibited a wide range of oral side effects during therapy. Lesions observed during the first 2 wk prior to engraftment of the donor marrow were related to the chemo- and radiotherapy given. Oral ulcerations were seen in 34% of the children. Children given methotrexate as graft-versus-host disease (GVHD) prophylaxis exhibited oral ulcerations significantly (P less than 0.05) more often than those given cyclosporin. Oral lesions related to acute GVHD were only observed in two patients. Reactivating herpes simplex virus infection was seen in 35% of the children who were seropositive prior to BMT. An extensive oral candidiasis was observed in 15% of the patients. All six children with a chronic GVHD exhibited changes in the oral mucosa 2-4 yr after transplantation such as erythma of the mucous membranes, tongue atrophy and also lichenoid changes in the buccal mucosa.

Antineoplastic Agents↗
PubMed1988

Increased (L+)-lactic acid production in lysozyme-inactivated suspensions of human dental plaque.

The effect of lysozyme-inactivation on L(+)-lactic acid (LA) production in dental plaque suspensions was evaluated. From 10 children 24-h plaque was collected and lysozyme activity inhibited by addition of goat antiserum to human lysozyme. Acid production was stimulated by addition of glucose. The results showed significantly increased LA levels (50-150%) in lysozyme-inactivated plaque suspensions from 8 of the subjects compared to untreated controls. The increase in acid production activity was not related to plaque lysozyme levels. The findings indicate that the presence of lysozyme may be limiting on acid production in the early dental plaque.

Adolescent↗
PubMed1987

Lysozyme activity and L(+)-lactic acid production in saliva in schoolchildren with high Lactobacillus counts.

Out of 374 schoolchildren, aged 13-15 yr, 42 with high counts of salivary lactobacilli (greater than or equal to 10(5] were selected for this study. Lysozyme activity in saliva and L(+)-lactic acid (LA) production after addition of glucose were determined. The mean values of lysozyme activity and LA concentration were 19.4 micrograms/ml and 1.4 mmol/l respectively. The levels of LA produced without addition of glucose were less than 0.2 mmol/l. The results showed a statistically significant (P less than 0.05) negative correlation between lysozyme activity and the levels of LA produced. The findings of this study suggest that lysozyme may be of importance in limiting acid production in saliva.

Adolescent↗
PubMed1987

Effect of inactivated salivary lysozyme on L(+)-lactic acid production in saliva and in cultures of Streptococcus mutans BHT.

The aim of this study was to evaluate the antimicrobial contribution of human lysozyme in saliva. In one series of experiments, L(+)-lactic acid (LA) production in exponential phase cultures of Streptococcus mutans BHT treated with lysozyme-deficient salivary supernatant was determined. In other experiments, LA concentration was measured in whole saliva samples from 22 school-children where the lysozyme activity had been inhibited by the addition of goat antiserum to human lysozyme (GAsL). LA production in both S. mutants cultures and saliva samples was stimulated by D-glucose addition. The results indicated a time dependent increase (approximately 30%) in LA production in lysozyme-deficient reaction-mixtures compared to untreated controls. The mean LA concentration in lysozyme-inactivated whole saliva samples was significantly higher (p less than 0.01) compared to untreated saliva. However, in 4 out of 22 children the GAsL-treatment did not affect LA production. The individual differences could not be related to salivary secretion rate, lysozyme activity or the number of S. mutans and lactobacilli in saliva. The findings of this study suggest a protective role for lysozyme in limiting acid production in saliva, but individual differences exist.

Enzyme Activation↗
PubMed1985

Scanning electron microscopic study of Streptococcus mutans BHT lysed by lysozyme.

The effects of purified salivary lysozyme (HSL) and hen egg white lysozyme (HEWL) on the surface structure of Streptococcus mutans BHT were studied with the aid of scanning electron microscopy. In parallel experiments bacteriolysis was monitored by liberation of 3H-thymidine incorporated into the bacteria. Control cells maintained their shape and had intact cell walls during the experimental period. Exposure of the cells to HSL (5.0 U/ml) or HEWL (5.0 micrograms/ml) for 3 and 18 h resulted in progressive destruction of cell structure. Some cells exhibited ruptures of the cell walls on top of spherical swellings, predominantly located at the ends of the bacteria. After 18 h the majority were disrupted in the septal area leaving numerous empty cup shaped cell walls in the preparations. The findings of the electron microscopic examination were confirmed in the biochemical assay.

Animals↗
PubMed1984

Three-year study of the effect of fluoride varnish (Duraphat) on proximal caries progression in teenagers.

The effect of sodium fluoride varnish (Duraphat) applications on proximal caries progression was studied during a 3-yr period in 87 teenagers and compared to a control group (n = 107). In the fluoride varnish group the children were treated with fluoride varnish every third month during the experimental period. Caries lesions on the mesial surfaces of first premolars to the mesial surfaces of second molars were recorded annually on radiographs and an individual progression value was calculated. The study showed that topical application of fluoride varnish every third month significantly (P less than 0.05) reduced the progression of proximal caries lesions in premolars and molars. The most obvious reduction of caries progression was observed among children who developed between two and eight new proximal lesions during the test period. In the children with the highest caries activity (greater than nine new proximal lesions) Duraphat treatments did not significantly reduce proximal caries progression in premolars and molars.

Adolescent↗
PubMed1984

Influence of bacterial cell concentration and inorganic anions on lysis of Streptococcus mutans BHT by salivary lysozyme.

The aim of this work was to study the influence of bacterial cell concentrations and inorganic anions on lysis of Streptococcus mutans BHT by human salivary lysozyme (HSL). HSL was partly purified from saliva by ion exchange chromatography. The bacteria were grown in a synthetic medium containing 3H-thymidine to monitor DNA release. The experiments demonstrated that release of 3H-thymidine was dependent on the bacterial cell concentration and an apparent Km-value corresponding to approximately 2.9 X 10(8) cells/ml was calculated. The influence of I-, Br-, Cl-, F-, HCO3- and SCN- on bacteriolysis was studied. All anions tested were slightly inhibitory on the action of HSL. The inhibition varied from 7 to 76% depending on the ion and ionic strength. The order of addition of HSL and sodium chloride caused different lytic responses. This was reflected by the amount of HSL adsorbed by the bacteria.

Animals↗
PubMed1983

Lysis of Streptococcus mutans BHT by salivary lysozyme.

The aim of this work was to study the bacteriolytic ability of human salivary lysozyme (HSL) on Streptococcus mutans BHT. The cells were grown in a synthetic medium containing 3H-thymidine to monitor DNA release after incubation with either HSL, purified by ion exchange chromatography, or hen egg white lysozyme (HEWL). The experiments demonstrated that HSL as well as HEWL could liberate DNA from cells. The lysis was dependent on enzyme concentration as well as incubation-time. Approximately 80% of the 3H-thymidine was released at final concentrations of 4.5 micrograms/ml and incubation-times exceeding 16 hr. Additional treatment of the suspensions with DNase increased the levels of released radioisotopes. The lytic ability of HSL and HEWL was similar at low concentrations. HSL inactivated with goat antiserum to human lysozyme decreased the liberation of DNA by about 70%. This study suggests that HSL can lyse S. mutans BHT without presence of inorganic ions.

Bacteriolysis↗
PubMed1979

Lysozyme activity in saliva from children with various degree of gingivitis.

The lysozyme activity was determined in paraffin stimulated whole saliva from 51 randomly selected children. The average age was 6.5 years. The children were divided into four groups according to their degree of gingival inflammation. An agardiffusion method was used with Micrococcus lysodeikticus as indicator of the lysozyme activity. The mean value of the lysozyme activity was determined to 48.4 microgram/ml. In the non-inflamed group the enzyme activity was 8.7 microgram/ml, whereas it was lower, 31.5 microgram/ml, in children with inflamed gingiva. The correlation coefficient (p less than 0.05) suggest that there is a negative relationship between saliva lysozyme and the degree of gingival inflammation. Furthermore this study indicates that lysozyme acts as one of the resistant-factors against gingival inflammation in young individuals.

Child↗
PubMedDate not supplied

Prediction of caries in pre-school children in relation to fluoride exposure.

The levels of salivary mutans streptococci and caries experience were used as predictors for caries incidence in 3 groups of pre-school children from areas with different levels of natural and topical fluoride exposure. Altogether 1022 children, 4-5 years of age at baseline, were examined according to the WHO-criteria and followed for 2 years. The low fluoride group (n = 374) had a low fluoride level in the piped water and no topical fluoride applications; the F-varnish group (n = 442) had low water fluoride but semiannual topical applications of a fluoride varnish; the optimal fluoride group (n = 206) had an optimal level of fluoride in the drinking water and semiannual F-varnish applications. The number of salivary mutans streptococci was estimated and scored at baseline with the Strip mutans chair-side method. The sampling procedure was repeated in 337 children of the low fluoride group 3 weeks after baseline. In comparison with the low fluoride group, caries incidence was 30% and 60% lower in the F-varnish and the optimal fluoride group respectively. The caries predictive ability decreased with increasing fluoride exposure. The sum of sensitivity and specificity decreased from 151% (65% + 86%) in the low fluoride group to 131% (40% + 91%) in the optimal fluoride group. The positive predictive value was highest (62%) in the low fluoride group. Repeated salivary samplings at baseline did not improve the caries predictive power. The results suggest that the overall fluoride exposure should be taken into account when caries risk assessment strategies for preschool children are developed and implemented.

Child, Preschool↗
PubMedDate not supplied

Effect of quarterly treatments with a chlorhexidine and a fluoride varnish on approximal caries in caries-susceptible teenagers: a 3-year clinical study.

The aim of this study was to compare the effect of two different dental varnishes on approximal caries incidence in teenagers with proven caries susceptibility during a 3-year period. Two hundred 13- to 14-year-old subjects exhibiting at least two approximal enamel caries lesions were selected to take part in the study. One hundred and eighty subjects participated after informed consent and were randomly assigned to two equally sized groups. One group was treated with a fluoride varnish (FV, Fluor Protector) containing 0.1% F every 3rd month and the participants of the other group were treated in the same mode with a chlorhexidine varnish (CV, Cervitec((R))) containing 1% chlorhexidine and 1% thymol. In total, each subject was treated 12 times during the experimental period. Approximal caries including enamel lesions (DMFS(appr)) were recorded from four bitewing radiographs exposed at the start and end of the study. The mean (+/-SD) caries prevalence at baseline was 2.2+/-3.4 in the FV group and 2.5+/-4.0 in the CV group. After 3 years, the average approximal caries incidence was 2.7+/-3.1 and 3.1+/-3.5 in the FV and CV groups, respectively. The differences at baseline and after 3 years were not statistically significant. In conclusion, treatments every 3rd month with either a fluoride- or a chlorhexidine/thymol-containing varnish showed a promising effect with low approximal caries incidence and progression in teenagers with proven caries susceptibility.

Adolescent↗