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Biomedical subjects

J D Rudney

Publications and source records attributed to J D Rudney.

44 records · Page 3Linked to original sources
PubMed1987

Responses of platelets to strains of streptococcus sanguis: findings in healthy subjects, Bernard-Soulier, Glanzmann's, and collagen-unresponsive patients.

The ability of endocarditis and dental strains of Streptococcus sanguis to induce platelet aggregation in plasma (PRP) from normal subjects were examined and compared to responses of PRP with known platelet membrane glycoprotein (GP) and response defects. S. sanguis strains differed in their ability to induce normal PRPs to aggregate. Strains that induced PRP aggregation in more than 60% of donors were significantly faster agonists (mean lag times to onset of aggregation less than 6 min) than those strains inducing response in PRPs of fewer than 60% of donors. Platelets from patients with Bernard-Soulier syndrome aggregated in response to strains of S. sanguis. In contrast, platelets from patients with Glanzmann's thrombasthenia and from a patient with a specific defect in response to collagen were unresponsive to S. sanguis. These observations show that GPIb and V are not essential, but GPIIb-IIIa and GPIa are important in the platelet response mechanism to S. sanguis. Indeed, the data suggests that the platelet interaction mechanisms of S. sanguis and collagen may be similar.

Bernard-Soulier Syndrome↗
PubMed1985

Correlations between human salivary levels of lysozyme, lactoferrin, salivary peroxidase and secretory immunoglobulin A with different stimulatory states and over time.

Within-subject correlations for the levels of these salivary proteins were determined in unstimulated and stimulated parotid saliva collected from 8 subjects and for stimulated parotid saliva collected from the same subjects once a week for a 4-week period. Initial correlations between unstimulated and stimulated samples were high and statistically significant (p less than 0.05) for all four proteins. When data were adjusted for variation attributable to flow rate and total protein, some correlations remained the same and those for lysozyme, lactoferrin and salivary peroxidase increased. However, the correlation for secretory immunoglobulin A decreased to a point where it was no longer statistically significant. In the weekly comparison, within-subject correlations across weeks were significant (p less than or equal to 0.05) for lysozyme, lactoferrin and salivary peroxidase, but not for immunoglobulin A. After adjustment for flow rate and total protein, the pattern of correlation was unchanged. Thus the relative rankings of subjects for levels of lysozyme, lactoferrin or salivary peroxidase may be consistent across stimulatory states, even though absolute concentrations may change; levels of these proteins in stimulated parotid saliva may be maintained over time. Secretory immunoglobulin A appears to be more subject to short-term variation.

Adult↗
PubMed1985

Relationships between levels of lysozyme, lactoferrin, salivary peroxidase, and secretory immunoglobulin A in stimulated parotid saliva.

Recent studies suggest that salivary lysozyme (Lz), lactoferrin (Lf), peroxidase (Spx), and secretory immunoglobulin A (sIgA) may interact in a common antimicrobial system. A multiple protein approach therefore may be needed to determine the role of this system in oral health and ecology. In the present study we investigate the relationships between levels of Lz, Lf, Spx, and sIgA (adjusted for flow rate and total protein) in stimulated parotid saliva from 44 dental students. Principal components analysis was used to determine major patterns of intercorrelation between variables; cluster analysis was used to identify groups of subjects with similar salivary profiles for Lz, Lf, Spx, and sIgA. Spx tended to vary independently of Lz and Lf, which, in turn, tended to vary together. sIgA showed a weak negative relationship with Spx and a weak positive relationship with Lz and Lf. Six major clusters of subjects with similar antimicrobial protein profiles were found. These were significantly different at P less than 0.0001. Spx was the most important determinant of cluster membership followed (in order of importance) by Lz, Lf, and sIgA. Cluster profiles were Spx-, sIgAmu, Lf-, Lz-; Spx-, sIgA+, Lfmu, Lz+; Spxmu, sIgAmu, Lfmu, Lzmu; Spx+, sIgA-, Lf-, Lz-; Spx+, sIgAmu, Lf+, Lz-; and Spx+, sIgAmu, Lf+, Lz+ (-, mu, and + refer to the position of the cluster mean each variable relative to the overall mean for that variable). Results suggest that clusters may be a product of independent variation in the secretory activity of acinar and intercalated duct cells.

Adult↗
PubMed1983

Dental indicators of growth disturbance in a series of ancient Lower Nubian populations: changes over time.

Previous studies of accentuated striae of Retzius in tooth enamel suggest that early childhood growth disturbance tends to be severe in state-level agricultural societies. The present study investigates the diachronic stability of levels of growth disturbance with a series of Lower Nubian agricultural states broadly similar in terms of mode of subsistence and way of life. The sample consists of 114 first permanent molars from the Meroitic (100 B.C. to 300 A.D.) and X-Group (300 to 600 A.D.) cultures. These teeth were sectioned according to standard histological technique. Data on the frequency and severity of accentuated striae of Retzius were then used to derive estimates of the magnitude of individual growth disturbance. Populations were compared by means of a two-way ANOVA, with growth disturbance as the dependent variable, and age and population as the independent variables. The results show that those dying in childhood experienced significantly higher levels of early childhood growth disturbance than did those surviving to adulthood. The results also show a decline in growth disturbance levels over time. Both X-Group children and X-Group adults experience significantly less early childhood growth disturbance than their Meroitic counterparts. These results suggest an improvement in child health status from Meroitic to X-Group times. Tentative explanatory hypotheses imply an increase in village autonomy, an increase in helminthic disease related to a change in irrigation technology, or direct and indirect effects of consumption of naturally-occurring tetracyclines. These hypotheses are not mutually exclusive, and further research is needed before any of them can be tested.

Adolescent↗
PubMed1983

Interobserver reliability of methods for paleopathological diagnosis of dental caries.

There is disagreement as to whether clinical methods of caries diagnosis will produce reliable results in skeletal material, and studies vary greatly in the extent to which such methods are employed. The purpose of this study is, therefore, to evaluate the interobserver reliability of visual, tactile, and radiographic methods of scoring dental caries in ancient populations. Thirty-three individuals from a Mogollon skeletal sample were scored on three occasions by pairs of examiners. The first exam employed visual criteria alone. In the second exam, visual methods were supplemented with the dental explorer. For the third exam, mesial and distal surfaces were scored from "intraoral" radiographs. Examiners worked independently, but did calibrate on material from clinical populations prior to the second and third exams. Exams were conducted on a "blind" basis, and analysis was delayed until all exams were completed. Caries scores were expressed as a percentage of total surfaces present per individual. Repeat-measures ANOVA and intraclass correlation coefficients (ICC) were used to estimate interobserver reliabilities. For visual scores, ICC = 0.97, and there is no significant difference between examiners (P = 0.897). For visual plus explorer scores, ICC drops to 0.90, and there is a significant difference between examiners (P = 0.003). For the radiographs, ICC = 0.86, and there is no significant difference between observers (P = 0.117). These results suggest that clinical methods are less reliable in skeletal populations.(ABSTRACT TRUNCATED AT 250 WORDS)

Dental Caries↗
PubMedDate not supplied

Effect of peripheral electrical stimulation on measures of tooth pain threshold and oral soft tissue comfort in children.

The effect of peripheral electrical stimulation on tooth pain threshold and comfort of oral soft tissue was evaluated in 30 children, using a double-blind, crossover, study design. Tooth pain threshold was measured before and after 8 minutes of electrical or sham stimulation. Comfort of oral soft tissue during placement of a rubber dam clamp was evaluated 3 minutes after electrical or sham stimulation was begun. Comfort level was rated by each subject and by the investigator, using a visual analog scale (VAS). Heart rate was measured before and immediately following placement of the clamp. Electrical stimulation significantly increased tooth pain threshold and reduced the cardiovascular stress response without altering comfort levels during placement of the clamp. These findings suggest that peripheral electrical stimulation applied in a pediatric dental setting alters sensory aspects of pain but not affective aspects of comfort.

Adolescent↗
PubMedDate not supplied

Influence of pH on intestinal fluoride transport in vitro.

The effect of pH on intestinal fluoride (F) absorption was investigated in vitro using isolated segments of dog jejunum in a 2-chamber system. The pH of the mucosal buffer was varied in the range 6.5-8.2, and F concentration in the range 0.11-1.1 mM (2.1-21 ppm F). The serosal buffer was held constant at pH 7.5. No effect of pH within this physiological range was observed on F transport across the intestinal segment. Much lower pH values on the mucosal side inhibited F transport, but this appeared to be secondary to toxic effects on the epithelium, including an inhibition of water transport. Within the range tested, no evidence was found supporting the concept that F transport across intestinal epithelium occurs as the undissociated hydrogen fluoride (HF).

Analysis of Variance↗