Biomedical subjects

J D Rudney

Publications and source records attributed to J D Rudney.

At least 37 records · Page 2Linked to original sources

PubMed1995

Saliva protein binding to layers of oral streptococci in vitro and in vivo.

This paper reports a system for measuring saliva protein binding to oral streptococci. Enamel chips with layers of Streptococcus gordonii Blackburn or Streptococcus oralis 10557 were incubated in vitro with whole saliva from eight persons. Blackburn bound significantly more amylase than 10557; no strain differences were seen for lysozyme or lactoferrin. There were significant correlations between saliva and bound amylase and lactoferrin. Blackburn and 10557 chips were then placed in ten subjects. Sites included the buccal left and right upper premolars and molars (UL, UR), labial upper central incisors (UC), and lingual lower central incisors (LL). That study was repeated three months later; chips with Streptococcus sanguis 13379 were also placed then. Blackburn bound significantly more amylase than the other strains. Blackburn and 10557 both bound the most amylase at UL and UR, and the least amylase at UC. However, strain 13379 bound less amylase at UL. That strain also bound significantly less sIgA at UL. All three strains bound the least sIgA at UC. Lysozyme and lactoferrin binding showed few differences among sites or strains. Bound protein concentrations were significantly correlated across sites and strains within subjects, but not correlated with whole saliva. Strain differences may reflect species differences in amylase binding, or differences in species-specific sIgA titers. Site differences may indicate local variation in protein availability. Differences between chip correlations with whole saliva in vitro and in vivo suggest that the salivary film may be modified as it flows over tooth surfaces.

Amylases↗

PubMed1995

Does variability in salivary protein concentrations influence oral microbial ecology and oral health?

Salivary protein interactions with oral microbes in vitro include aggregation, adherence, cell-killing, inhibition of metabolism, and nutrition. Such interactions might be expected to influence oral ecology. However, inconsistent results have been obtained from in vivo tests of the hypothesis that quantitative variation in salivary protein concentrations will affect oral disease prevalence. Results may have been influenced by choices made during study design, including saliva source, stimulation status, control for flow rate, and assay methods. Salivary protein concentrations also may be subject to circadian variation. Values for saliva collected at the same time of day tend to remain consistent within subjects, but events such as stress, inflammation, infection, menstruation, or pregnancy may induce short-term changes. Long-term factors such as aging, systemic disease, or medication likewise may influence salivary protein concentrations. Such sources of variation may increase the sample size needed to find statistically significant differences. Clinical studies also must consider factors such as human population variation, strain and species differences in protein-microbe interactions, protein polymorphism, and synergistic or antagonistic interaction between proteins. Salivary proteins may form heterotypic complexes with unique effects, and different proteins may exert redundant effects. Patterns of protein-microbe interaction also may differ between oral sites. Future clinical studies must take those factors into account. Promising approaches might involve meta-analysis or multi-center studies, retrospective and prospective longitudinal designs, short-term measurement of salivary protein effects, and consideration of individual variation in multiple protein effects such as aggregation, adherence, and cell-killing.

Aging↗

PubMed1995

Therapeutic advantage of recombinant human plasminogen activator in endocarditis: evidence from experiments in rabbits.

In infective endocarditis vegetations are stabilized by fibrin. To learn if fibrin digestion would be therapeutic, experimental endocarditis was induced in rabbits by inoculation with a platelet-aggregating strain (Agg+) of Streptococcus sanguis and treated with recombinant tissue plasminogen activator (rt-PA), rt-PA with penicillin, or penicillin alone. Control rabbits were inoculated with saline. All treatments of Agg+ endocarditis reduced the mass of valvular vegetations and clinical signs of endocarditis, including the frequency of left axis deviation and heart ischemia. rt-PA with penicillin was more effective than penicillin or rt-PA alone, reducing the mass of vegetations and clinical signs to that of saline controls. Within 50 min, rt-PA cleared 5-fold more 111Indium-labelled platelets from the heart than untreated rabbits and 1.4-fold more after 3 days. Combined with penicillin, thrombolytic therapy for human endocarditis should be reconsidered.

Animals↗

PubMed1994

Genetic contributions to saliva protein concentrations in adult human twins.

The heritability of saliva protein concentrations was investigated in stored samples of clarified stimulated whole saliva from adult twins participating in a study of periodontal disease genetics. Saliva was obtained from 29 monozygous and 20 dizygous twin pairs. Visits were scheduled so that both twins in a pair donated saliva at the same time of day. Flow rate was determined, and frozen samples later assayed for lactoferrin, lysozyme, secretory IgA, total peroxidase, myeloperoxidase and total protein. Pairs were always assayed together. Within- and between-pair variances were used to estimate twin intraclass correlations. Pearson correlations were used to estimate associations between saliva variables and clinical indices of gingivitis, dental plaque, periodontal attachment loss, and probing depth. Significant genetic contributions to variance were seen for total protein, lactoferrin, and total peroxidase. Total protein showed a significant positive correlation with gingivitis. There were no other correlations with clinical indices, and intraclass correlations for saliva variables did not change after adjustment for gingivitis. Dizygous twin correlations were higher than monozygous twin correlations for flow rate, lysozyme, and secretory IgA. That may be an artefact due to small numbers of pairs. It seems unlikely that a common environmental factor would strongly affect saliva in twins living apart as adults. Present findings, taken as sib correlations, support a genetic contribution to saliva protein concentrations. Problems with the twin model in saliva might be resolved by longitudinal studies of large numbers of twins.

Adult↗

PubMed1994

The effects of sterilization on addition silicone impressions in custom and stock metal trays.

Five groups of addition silicone impressions (four made in custom autopolymerizing acrylic resin trays and one in stock metal rim-lock trays) were made of a stainless-steel master die. The first group (control group) was not sterilized. The second group was sterilized in an ethylene oxide gas autoclave, the third group in a steam autoclave, and the fourth and fifth groups by immersion for 12 hours in 2% glutaraldehyde. Casts made from each sterilization group were found to be significantly different from control impressions by multivariate analysis of variance and should not be used to fabricate prostheses.

Dental Impression Materials↗

PubMed1994

Use of restriction fragment polymorphism analysis of rRNA genes to assign species to unknown clinical isolates of oral viridans streptococci.

This study evaluated restriction fragment length polymorphisms of rRNA genes (ribotyping) for genotypic identification of 53 oral isolates classified as "Streptococcus sanguis" by colony morphology. Isolates were from 8-h buccal plaque on lower first permanent molars of 20 subjects. DNA was digested with AatII and hybridized with digoxygenin-labeled cDNA of Escherichia coli 16S and 23S rRNA. Strains were ribotyped again with AlwNI or PvuII on the basis of the presence or absence of a 2,290-bp AatII band. Band patterns were compared with reference ribotypes for Streptococcus gordonii, Streptococcus sanguis, Streptococcus crista, Streptococcus oralis, Streptococcus mitis, and Streptococcus parasanguis strains. Forty-eight isolates could be assigned to a species (22 S. sanguis, 14 S. oralis, 12 S. gordonii). Multiple species were seen in 14 subjects; multiple strains of the same species occurred in 11 subjects. Our findings suggest that ribotyping can be used for genotypic identification of S. sanguis, S. oralis, and S. gordonii isolates.

Bacterial Typing Techniques↗

PubMed1993

Longitudinal study of relations between human salivary antimicrobial proteins and measures of dental plaque accumulation and composition.

Many studies have attempted to relate levels of antimicrobial proteins in saliva to oral health; results have been inconsistent, and one reason might be inconsistency of measures of plaque and saliva within subjects. This study investigated associations between plaque and salivary variables in longitudinal data. Whole saliva, and 8-h plaque pooled from buccal first permanent molars, was obtained from 32 dental students on Tuesdays from 3:00-6:00 p.m. over 4 weeks. Salivary flow rate was determined, and samples were assayed for lysozyme, lactoferrin, total peroxidase, myeloperoxidase, OSCN-, sIgA and total protein. Colonies on mitis-salivarius agar were assigned to Streptococcus sanguis, Strep. mutans or Strep. salivarius on the basis of morphology, supplemented by the API Rapid Strep identification system. Consistency of values within subjects across weeks was evaluated by repeat-measures analysis of variance and intraclass correlation; data were transformed to reduce skewness. Pearson's r was used to determine associations between plaque and salivary variables. Significant intraclass correlations (alpha = 0.05) were found for all salivary variables except myeloperoxidase, and for total flora, total streptococci, Strep. sanguis and Strep. sanguis as a proportion of total streptococci. Significant Pearson correlations with Strep. sanguis as a proportion of total streptococci were found for total protein (r = -0.24), sIgA (r = -0.22), lactoferrin (r = -0.19) and OSCN- (r = 0.20) when data from all weeks were pooled (n = 128). Strep. sanguis proportions tended to be low in subjects with high values for salivary proteins; the range of proportions was wider in subjects with low salivary values. These findings suggest some consistency of weekly values for many plaque and salivary variables. They also support previous cross-sectional data which suggested that salivary antimicrobial proteins may have some effect on plaque composition. This study was made before recent revisions in streptococcal taxonomy, and further research is needed to clarify interactions of salivary proteins with currently defined species.

Bacteria↗

PubMed1993

Dental plaque development on defined streptococcal surfaces.

Coaggregations between bacterial species have been widely studied in vitro but not in the mouth. A new in vivo assay was used to measure the rate and composition of indigenous plaque formation onto bovine enamel chips covered with a continuous layer of bacteria. Chips were covered with Streptococcus oralis ATCC 10557, which coaggregated with many oral species, or Streptococcus gordonii S7, which did not coaggregate with these oral species, and placed in the mouth for 4 and 24 h. There were no differences in the number of most indigenous bacterial species isolated from the two streptococcal surfaces. However, the number of Actinomyces viscosus as a proportion of total Actinomyces spp. was significantly different on the two surfaces at 24 h. With the exception of Actinomyces naeslundii and A. viscosus removed from the S7 surface, all indigenous species increased significantly in number from 4 to 24 h, irrespective of the streptococcal surface. This study demonstrated that interbacterial coaggregation had only a limited effect on in vivo plaque development. Thus suggesting that environmental factors, growth or other adherence phenomena are dominant in in vivo plaque formation.

Actinomyces↗

PubMed1993

Species identification of oral viridans streptococci by restriction fragment polymorphism analysis of rRNA genes.

Oral streptococci formerly classified as Streptococcus sanguis have been divided into six genetic groups. Methods to identify those species by genotype are needed. This study compared restriction fragment polymorphisms of rRNA genes (ribotypes) for seven S. gordonii, three S. sanguis, four S. oralis, three S. mitis, one S. crista, and seven S. parasanguis strains classified in previous DNA hybridization studies, as well as one clinical isolate. DNA was digested with HindIII, PvuII, HindIII and PvuII combined, EcoRI, BamHI, AatII, AlwNI, and DraII. DNA fragments were hybridized with a digoxigenin-labeled cDNA probe obtained by reverse transcription of Escherichia coli 16S and 23S rRNA. S. oralis, S. mitis, and S. parasanguis all showed an isolated 2,290-bp band in AatII ribotypes that was absent from S. gordonii, S. sanguis, and S. crista. The last three groups showed species-specific bands with AatII and also with PvuII. S. oralis could be distinguished from S. mitis and S. parasanguis in AlwNI and DraII ribotypes. S. mitis and S. parasanguis could not be distinguished, since they shared multiple bands in PvuII, AlwNI, and EcoRI patterns. The clinical isolate in the panel was very similar to S. sanguis by all enzymes used. Our findings suggest that ribotyping may be useful for genotypic identification of oral viridans streptococci. Initial digests of clinical isolates might be made with AatII, followed by PvuII or AlwNI. Isolates then could be identified by comparing ribotype patterns with those of reference strains. This approach could facilitate clinical studies of these newly defined species.

Bacterial Typing Techniques↗

PubMed1992

Restriction endonuclease-fragment polymorphisms of oral viridans streptococci, compared by conventional and field-inversion gel electrophoresis.

Oral streptococci formerly classified as Streptococcus sanguis or Streptococcus mitis have recently been divided into four species. Two additional species have also been proposed for this group. Each species is genetically distinct, but they have many traits in common, which makes it difficult for clinical isolates to be identified by phenotypic tests. Genotypic comparison may provide an alternative approach. This study used DNA fingerprint analysis for comparison of genotypes of 21 reference strains--classified as Streptococcus gordonii, Streptococcus sanguis, Streptococcus oralis, "Streptococcus parasanguis", or "Streptococcus crista" in previous DNA hybridization studies--and 17 clinical and laboratory strains placed in those groups on the basis of phenotypic tests. HinDIII and PvuII digests were run in conventional horizontal agarose gels. SfiI digests of reference strains and two laboratory strains were run in field-inversion gels. Fingerprint patterns were compared by visual examination, cluster analysis of densitometric traces, and lane-matching software. Only two "S. crista" strains and two parent mutant lineages showed fingerprint patterns that were identical by visual examination. Fingerprint patterns of all other strains were unique. Cluster analysis results could not be considered valid, since replicate lanes in different gels were not grouped together. HinDIII and PvuII digests contained too many bands for correct matching by lane-matching software. SfiI digests were correctly matched by computer, with the same results as visual examination. Results indicate that the diversity of strains within these streptococcal species was too great to permit species identification by DNA fingerprint patterns. This genotypic diversity suggests that isolates from unrelated hosts may have been separate for long periods of time.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Proteins↗

PubMed1991

Antimicrobial proteins in human unstimulated whole saliva in relation to each other, and to measures of health status, dental plaque accumulation and composition.

Saliva antimicrobial proteins may interact in a common system to influence the oral ecology. Clinical studies of antimicrobial protein action thus may require a multiple-protein approach. Multivariate statistical methods have been used to describe possible patterns of interaction for lysozyme, lactoferrin, salivary peroxidase and secretory IgA in stimulated parotid saliva. However, oral microbes are most likely to encounter antimicrobial proteins in mixed resting saliva. Relationships among levels of lysozyme, lactoferrin, salivary peroxidase, and secretory IgA therefore were investigated in whole saliva from 216 subjects, and an attempt made to relate interperson variation in those proteins to differences in health and status, and dental plaque accumulation and composition. All proteins were significantly (alpha = 0.05) correlated with each other (r = 0.38-0.52, p less than 0.001). There was only one axis of common variation among proteins, and that axis was significantly correlated (p less than 0.001) with total protein (r = 0.84) and flow rate (r = -0.56). That pattern deviated from the previous finding that proteins of acinar origin tended to vary independently from proteins of ductal origin in stimulated parotid saliva. The difference between parotid and whole saliva may reflect constitutive secretion of all proteins at low levels of stimulation. Common variation of unstimulated saliva proteins suggests that antimicrobial actions can be compared in subjects at population extremes. There were no significant associations between antimicrobial proteins in whole saliva and measures of health status or plaque accumulation. However, the proportions of Streptococcus sanguis were significantly correlated with lysozyme (r = -0.26), lactoferrin (r = -0.34), peroxidase (r = -0.30), total protein (r = -0.37), flow rate (r = 0.24) and principal-components scores (r = -0.33) in a subset of subjects (n = 85) where commercial biochemical tests were used to supplement species identification by colony morphology. Those findings may indicate that saliva antimicrobial proteins can affect the composition of dental plaque.

Adolescent↗

PubMed1991

Dimensional stability of a polyvinylsiloxane impression material following ethylene oxide and steam autoclave sterilization.

Polyvinlsiloxane impressions were made from a stainless steel master die machined to stimulate five full veneer crown preparations symmetrically placed in an arch form. Three groups of 10 impressions each were made. Treatment groups were sterilized using an ethylene oxide gas and a conventional steam autoclave. Casts were poured and intrapreparation, height, and diameter measurements were made using a stereomicroscope, a digital electronic caliper, and a 1-inch travel dial indicator. Analysis of dimensional changes for the two groups showed that casts made from impressions sterilized by ethylene oxide are acceptable for use in the construction of fixed or removable prostheses. Casts made from impressions sterilized in a steam autoclave can be used for the fabrication of diagnostic casts and some transitional prostheses, but not for routine construction of crowns or fixed partial dentures.

Analysis of Variance↗

PubMed1990

Implications of a model from olfactory research for the use of secretion rates in salivary studies.

Secretion rates (amount protein per unit time) are often used as a means of adjusting saliva protein concentrations for the effects of variation in flow rate. However, findings in olfactory physiology may indicate a problem with that approach: olfactory neurones respond differently to a small amount of odorant over a short time than to twice that quantity over twice the time, although secretion rates remain the same. Whether a similar variation in amounts and times occurs in persons with similar secretion rates for lysozyme, lactoferrin, salivary peroxidase, sIgA, or total protein in stimulated parotid saliva was investigated. The data used were from 2 groups of 44 and 198 subjects previously found to differ in flow rate and concentrations of antimicrobial proteins. Multidimensional plots of secretion rates, amounts and times were generated for each protein. Wide ranges of amounts and times were seen among persons within the same percentile for secretion rate for every protein in both groups. These amounted to as much as a thirteen-fold difference in amounts and times. Experimental studies are needed to determine whether such differences affect the action of saliva proteins.

Humans↗

PubMed1990

Enamel abrasion from ceramic orthodontic brackets under an artificial oral environment.

The purpose of this investigation was to examine the potential enamel abrasion on contact with stainless steel and various ceramic orthodontic brackets under a simulated oral environment. Three groups of eight lower premolar ceramic brackets and one group of eight stainless steel brackets were used from four different manufacturers. An upper premolar was brought in contact with the bracket bonded to a lower premolar tooth and subjected to a lateral excursion type of movement by the artificial oral environment. A constant load of approximately 2 lb was used for the masticatory force. The rate of chewing was 1 cycle/sec. The teeth were subjected to 15, 60, and 100 masticatory cycles. The before-and-after occlusal surfaces of the upper premolars were compared by means of a computerized profiling system and the enamel volume loss was calculated. Qualitative changes, such as rate of enamel wear, were examined visually by means of computer graphics and the scanning electron microscope. Abrasion scores (mean +/- SD) in mm3 were 0.015 +/- 0.01 from the metal brackets and 0.135 +/- 0.103, 0.255 +/- 0.242, and 0.581 +/- 0.524 from the three ceramic bracket groups. The abrasion scores were significantly different at p less than 0.05. Ceramic brackets caused significantly greater enamel abrasion than stainless steel brackets. Artificial mouth in vitro testing gave a good indication of clinical performance of orthodontic brackets.

Aluminum↗

PubMed1990

Musculoskeletal pain among Minnesota dental hygienists.

Using a 33-item questionnaire, this study was conducted to determine the nature and prevalence of musculoskeletal pain in dental hygienists, and its effects on clinical practice. An 89% response was obtained from a random sample of 493 dental hygienists. Results revealed that 68% of the respondents reported having musculoskeletal pain in eight body locations the previous year. In addition, a large percentage of dental hygienists with a preexisting condition reported having musculoskeletal pain. Thirty-four percent stated that musculoskeletal pain had affected their clinical practice--forcing them to practice fewer days, decreasing their endurance, reducing speed and quality, and/or altering operating positions. The findings suggest that particular locations of pain could be related to dental hygiene practice. Further research is indicated to clarify specific patient-operator positions contributing to musculoskeletal pain so that prevention and early treatment become possible.

Adult↗

PubMed1990

Retentive strength of six temporary dental cements.

The retentive strength of three zinc oxide-eugenol cements and three noneugenol-containing zinc oxide cements and the effect of the addition of petrolatum on retention were tested. The addition of petrolatum was found to affect retention of the cements significantly. Retention strengths varied from 1.6 kg to 40.0 kg. Of the Class 1, Type 2, systems tested, noneugenol cements had higher retentive values than did the eugenol-containing cements.

Analysis of Variance↗

PubMed1990

Carpal tunnel syndrome among Minnesota dental hygienists.

Because of inherent aspects of clinical practice, dental hygiene practitioners may be at risk for developing carpal tunnel syndrome (CTS). A study was conducted to determine the prevalence of CTS among dental hygienists and its effects on clinical practice. A 33-item questionnaire was mailed to a random sample of 493 dental hygienists. A 90% response rate was achieved. Results revealed that 7% of the respondents had been diagnosed as having CTS. However, 63% had experienced one or more symptoms. Six percent reported that CTS had affected their clinical practice in ways such as limiting the number of days practiced, diminishing their hand strength, or forcing them to leave the profession. The findings suggest a need for dental hygienists to obtain information on CTS symptoms to facilitate early diagnosis and treatment.

Adult↗

PubMed1989

Relationships between human parotid saliva lysozyme lactoferrin, salivary peroxidase and secretory immunoglobulin A in a large sample population.

Saliva antimicrobial proteins may interact in a common system for host defence. This study applied multivariate analysis as a means of describing inter-person variation in that system. Samples of stimulated parotid saliva were obtained from 198 subjects. Flow rate was determined, and assays run for total protein, lysozyme, lactoferrin, salivary peroxidase and secretory IgA. Correlation and principal components analysis were used to define the relationships between proteins; cluster analysis was used to identify persons with similar protein concentration profiles. All proteins were significantly correlated at p less than 0.002 (r = 0.20-0.52). Principal components analysis identified a major axis of common variation, defined by lysozyme and salivary peroxidase, and a second axis, defined by secretory IgA. Lactoferrin was associated with both axes. Seven major groupings were obtained by cluster analysis; these were significantly different at p less than 0.001. Such groupings may prove useful in comparing the antimicrobial properties of saliva samples.

Adolescent↗