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Biomedical subjects

E Newbrun

Publications and source records attributed to E Newbrun.

At least 55 records · Page 3Linked to original sources
PubMed1985

A sweet dispute.

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Animals↗
PubMed1984

Characterization of a trypsin-like protease from the bacterium Bacteroides gingivalis isolated from human dental plaque.

A trypsin-like, membrane-bound protease from Bacteroides gingivalis was solubilized by Triton X-100 and partially purified by a combination of DEAE-Sepharose and aminophenylmercuric Sepharose chromatography, by taking advantage of the thiol group on the enzyme. The purified enzyme hydrolysed the synthetic substrates benzoyl-L-arginine-p-nitroanilide (L-BAPA), benzoyl-D,L-arginine-beta-naphthylamide (BANA) and tosyl-L-arginine methyl ester, as well as bovine serum albumin and ovalbumin, but not tosyl-L-lysine methyl ester. The enzyme activity was enhanced by SH-reagents and was inhibited to different degrees by SH-inhibitors, chelators and microbial low-molecular-weight inhibitors such as leupeptin, antipain and chymostatin. These microbial inhibitors could be of practical use as ligands for affinity chromatography for further purification. The possible involvement of the protease in periodontal diseases is also discussed.

Bacteroides↗
PubMed1984

Comparison of two screening tests for Streptococcus mutans and evaluation of their suitability for mass screenings and private practice.

Two simple microbiological tests for quantitating salivary Streptococcus mutans levels were compared with each other and evaluated for suitability for mass screenings and private practice. Both tests use mitis salivarius medium with bacitracin (MSB) and are selective for S. mutans. One test estimates colonies grown on agar (MSBA) and the other estimates colonies grown in broth that adhere to glass (MSBB). Both are scored from 1 (lowest) to 5 (highest). Children (293) in grades 5 and 6 in Tallahassee, Florida (nonfluoridated) were tested for S. mutans levels. Scores of children by both tests were significantly similar (chi 2, regression and Kappa statistical analysis). Correlation coefficients (regression) between scores and DMFS increments of the previous 4 yr were 0.35 (MSBA) and 0.26 (MSBB). Both tests were very good in identifying children with low caries increments, but positive scores did not correlate well with high caries increments. Sampling and interpreting took 2 min (MSBA) and 1 min (MSBB). Cost of MSBA/child was $1.15, and MSBB/child $1.25. These tests are economical and suitable for mass screenings to identify low risk populations who do not require preventive treatment.

Bacteriological Techniques↗
PubMed1984

Bactericidal action of bicarbonate ion on selected periodontal pathogenic microorganisms.

Organisms representative of soil, skin and fecal flora and of supragingival and subgingival flora were tested for inhibition of growth and killing by various salts (NaHCO3, NaCl, MgSO4). The antimicrobial activities of KHCO3, NaF, sodium lauryl sulfate (SLS) and chloramine T were also compared with that of NaHCO3, and the rate at which NaHCO3 exerts its bactericidal effect was studied. Suspected periodontal pathogens were more susceptible to salts than were control non-oral bacteria. Supragingival plaque organisms showed intermediate susceptibility. Periodontal pathogens were more susceptible to NaHCO3 than to NaCl; NaHCO3 and KHCO3 showed similar activity against all strains tested. Accordingly, the antibacterial activity of NaHCO3 is not simply an osmotic effect and is due to the bicarbonate ion. NaF, SLS and chloramine T had greater antimicrobial activity than NaHCO3. Supragingival bacteria required at least 6-hour exposure to 1.0 M NaHCO3 to produce 99% lethality (decrease colony-forming units by 2 log10), whereas selected periodontal pathogens were killed more rapidly (30-120 minutes). The higher the concentration of bicarbonate, the faster the lethality. Morphologic examination by transmission electron microscopy of organisms exposed to bactericidal salt concentrations revealed marked fibrillar condensations within the cytoplasm and shrinkage of the cytoplasm from the outer membrane. For NaHCO3 to be clinically effective, a high concentration must be introduced into the periodontal pocket and maintained there long enough to kill periodontal pathogens. Furthermore, NaHCO3 must be reapplied often enough to prevent recolonization by these pathogens. An advantage of NaHCO3 over NaF, SLS and other antimicrobial agents is its safety, availability and low cost.

Anti-Infective Agents, Local↗
PubMed1984

Root caries.

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Dental Caries↗
PubMed1983

Diffusion of small ionic species in human saliva, plaque fluid and plaque residue in vitro.

The tracer diffusion of small ionic species was investigated in water, saliva, dental plaque fluid and in plaque residue packed by a range of g forces. Diffusion rate of NaCl was similar in water, saliva and plaque fluid. The rate of CaCl2, NaH2PO4, Na2HPO4 and Na2SO4 was less in both saliva and plaque fluid. Diffusion rate of all ionic species tested was significantly less in plaque residue, most of all for CaCl2. In plaque fluid, plaque residue and water, an inverse linear relationship was found between log diffusion coefficients and log molecular weights. Increasing the tortuosity of the diffusion path, by packing plaque residue, further reduced the diffusion rate of NaH2PO4 and NaHCO3. In terms of three-dimensional diffusion, in plaque fluid, NaH2PO4, Na2HPO4 and CaCl2 diffused a distance of 300 microns within 25 s, whereas in plaque residue the equivalent diffusion times were 1.5-5.7 min. The unique retardation of CaCl2 in plaque residue implicated both non-specific and specific binding interactions.

Adolescent↗
PubMed1983

Inhibition by acarbose, nojirimycin and 1-deoxynojirimycin of glucosyltransferase produced by oral streptococci.

Acarbose is known to inhibit glucoamylase, maltase and sucrase. Our aim was to test whether it would also inhibit glucosyltransferase (GTF), to determine the type of inhibition and to compare the inhibitor potency of acarbose with that of nojirimycin and deoxynojirimycin, two other glucosidase inhibitors. Enzyme inhibition was measured either by chemical assay or by incorporation of radioactivity into product. Acarbose effectively inhibited the synthesis of polysaccharide by GTF from strains of Streptococcus mutans and Streptococcus sanguis, but not by fructosyltransferase from Streptococcus salivarius. Acarbose and 1-deoxynojirimycin were more potent inhibitors of GTF than maltose, nojirimycin or various amino sugars. The mechanism of action of these compounds is consistent with competitive inhibition.

1-Deoxynojirimycin↗
PubMed1983

Effect of dichloromethylene diphosphonate on fluoride balance in healthy men.

Healthy men with a daily intake of 0.37 mg fluoride were given dichloromethylene diphosphonate (Cl2MDP) or a placebo during a period of ambulation followed by bed rest. In both groups, serum ionic fluoride was unchanged, and fluoride balances were negative, but Cl2MDP significantly reduced loss of fluoride in the treated groups.

Adult↗
PubMed1983

Fluoride balances during early and late pregnancy.

Information useful in estimating the occupational fluoride hazard to pregnant women is scanty. Fluoride excretion and balances were determined in 18 young women--seven who were not pregnant, six in early pregnancy (second quarter), and five in late pregnancy (fourth quarter)--over a 20-day period under confined metabolic conditions. The total fluoride intake averaged 1.35 mg/day (0.35 mg from the diet, 1 mg from a mineral capsule). Urinary fluoride excretion levels for the three groups were similar and averaged 0.95, 1.03, and 1.15 mg/day, respectively. On the average, 88% of the total fluoride excreted was in the urine and the remainder in the feces. With few exceptions, the women in each group demonstrated small positive balances; the averages were +0.19, +0.16, and +0.14 mg/day, respectively. The differences were small and not statistically significant (p greater than 0.1). These data indicate that fluoride metabolism is not markedly altered during the course of pregnancy.

Adult↗
PubMed1982

Sugar and dental caries: a review of human studies.

Studies of special population groups, epidemiological surveys, controlled longitudinal studies of humans, and longitudinal studies on the effect of sugar substitutes indicate that frequent or high intake of sugary foods predisposes to dental decay. The relation is not always clear-cut, and most studies have important methodological problems and limitations. Longitudinal measurements of caries increments combined with multiple dietary histories are needed to clarity the association between caries and eating habits. The relative cariogenicity of specific foods can be assessed by a combination of in vitro tests, human in vivo tests, and experimental caries in animals. Human diets, however, vary in food items eaten and the frequency and sequence of eating, and these factors can affect the cariogenicity of a food. Therefore, reported correlations must be interpreted with caution.

Adolescent↗
PubMed1982

Fluoride balance studies in healthy men during bed rest with and without a fluoride supplement..

In a program of studies of disuse osteoporosis, fluoride balances were determined in healthy men during ambulation and then during bed rest for 6 to 17 wk. Control subjects ingested basal diets containing 0.4 mg fluoride per day, whereas experimental subjects received 10-mg fluoride supplements in divided doses with meals. Fluoride and calcium were measured in diets, urine, and feces. Serum analyses included calcium and ionic fluoride. Fluoride balances during both phases were uniformly negative in control subjects (mean -0.46 mg/day) but uniformly positive in supplement subjects (mean +2.58 mg/day). Calcium balances were markedly negative during bed rest in both groups. Serum fluoride concentrations increased proportionally to fluoride intake, averaging 0.016 ppm in the controls and 0.045 ppm in the supplement subjects. The supplement of 10 mg fluoride daily did not protect against bed rest-induced calcium loss, or cause any clinical or laboratory abnormality in any subject.

Adult↗
PubMed1982

Criteria of cariogenicity for labeling foods.

Labeling of foods with respect to cariogenic potential is desirable and in the best interests of the consumer. Individual foods can be categorized according to their cariogenicity in animal tests using well-controlled and standardized conditions. In general, such tests have found that the cariogenicity of a food is directly proportional to its sugar content. Plaque pH response in vivo after ingestion of individual foods can be used for identifying foods that are safe for teeth and presumably noncariogenic. Clinical trials are not effective means of testing the cariogenicity of a specific food because it is impossible in humans to regulate the diet and sequence of eating foods during an extended period, and because most subjects already have a high sugar intake and high background caries activity.

Animals↗