PubMed Health⌕ Search

Biomedical subjects

R Dunford

Publications and source records attributed to R Dunford.

15 recordsLinked to original sources
PubMed1992

Levels of salivary cystatins in periodontally healthy and diseased older adults.

Cystatins are cysteine protease inhibitors present in a variety of tissues and body fluids, including saliva. One possible function of these molecules may be to modulate tissue destruction in periodontal diseases. To investigate the potential role of salivary cystatins in these events, the levels of cystatins in saliva from periodontally healthy and diseased individuals were measured by enzyme-linked immunosorbent assay. Flow rates and total protein content were determined in all the samples collected, while cysteine protease inhibitory activity was assessed in submandibular-sublingual secretions. Statistical analysis showed no significant differences in the levels and activity of salivary cystatins in periodontally healthy and diseased individuals. These findings suggest that comparing the levels of cystatins in glandular salivas may not be a suitable indicator of periodontal disease status.

Aged↗
PubMed1992

Clinical criteria for the definition of "established periodontitis".

The objective of The Present study was to define criteria for the diagnosis of "established periodontitis." This term will define subjects who have demonstrated clinical attachment loss, and as such can be considered to have periodontitis. Using these criteria, healthy and established periodontitis subjects were compared with respect to gender, race, and age. Five hundred and eight subjects including 248 females and 260 males between the ages of 25 to 73 (mean 44.6 years), were examined in this study. The clinical examination included: plaque assessment index (PAI); gingival assessment index (GAI); probing pocket depth (PPD); and clinical attachment level (CAL). The mean and frequency distribution of these parameters were analyzed by age and gender. CAL (mean 2.12 mm) showed constant and significant increases with age, ranging from a mean of 1.63 mm in subjects 25 to 34 years of age to a mean of 2.65 mm in subjects 65 to 74 years of age. Males exhibited higher mean values than females for all the measured parameters, which were statistically significant for PAI, PPD, and CAL. The frequency distribution of subjects with PPD and CAL beyond certain threshold levels showed an exponential decline and was correlated to both the severity of the most involved site as well as the number of sites beyond threshold levels. The clinical entity of "established periodontitis" is suggested based on the presence of CAL greater than or equal to 6 mm in 2 or more teeth and one or more sites with PPD greater than or equal to 5 mm. In the present study, 30.5% of the subjects fell into this category.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Plastid genome structure and plastid-related transcript levels in albino barley plants derived from another culture.

Southern analysis of DNA from four albino barley plants regenerated from microspores by direct embryogenesis revealed the presence of plastid genomes which had undergone deletion or alteration of specific restriction fragments (delta ptDNAs). In contrast, a fifth plant appeared to contain an intact plastid genome. All the albino plants studied contained reduced amounts of ptDNA, the most abundant restriction fragments being present at levels between 6% and 20% of those found in the leaves of green seedlings. Steady-state levels of transcripts from plastid and nuclear genes encoding plastid components were estimated by Northern analysis of RNA from albino plants. Transcripts from the plastid genes rbcL, psbD-psbC and the 16S and 23S rRNAs were undetectable or were present at greatly reduced levels in albino plants compared to those found in green leaves. Transcripts from the nuclear genes rbcS and cab, which encode chloroplast localised proteins, were also present at reduced levels in albino pollen plants. Levels of the nuclear encoded 25S rRNA, which is not a plastid component, were found to be identical in albino plants and green leaves suggesting that only the expression of plastid-related genes may be affected in albino plants. The general reduction of plastid-related transcripts was independent of the different patterns of ptDNA alteration seen in albino pollen plants.

Blotting, Southern↗
PubMed1991

Construction of yeast artificial chromosomes containing barley DNA and the identification of clones carrying copies of the repeated element BIS-1.

Yeast artificial chromosome (YAC) cloning vectors allow the isolation and analysis of very large segments of DNA. Barley DNA was cleaved with the rare-cutting restriction enzyme MluI and fractionated according to size on a linear sucrose gradient or by pulsed field gel electrophoresis. DNA fragments of approximately 50-250 kb were ligated with the YAC vector pYAC-RC and transformed into yeast spheroplasts. The presence of recombinant YACs with barley DNA inserts was established, and a number of clones containing copies of the repeated element BIS-1 were isolated. These results show that YAC cloning techniques can be successfully applied to the analysis of the barley genome.

Chromosomes, Fungal↗
PubMed1990

A computer program for calculating kappa: application to interexaminer agreement in periodontal research.

The kappa statistic is a frequently used measure of interobserver agreement when two or more observers are asked to rate the same items or subjects on some criterion. The advantage of the kappa statistic over simple agreement is that it corrects for agreement by chance. In dental research, because multiple examiners may be involved in assessing subject variables such as attachment loss, bleeding on probing, or periodontal pocket depth, some statistical measure of agreement is needed. The program described here was developed for estimating agreement among periodontal examiners, but also could be used in clinical teaching applications. Assumptions and limitations of the kappa statistic are discussed. Examples of outputs illustrate applications of the program.

Humans↗
PubMed1988

Studies of the induction of dominant lethals and translocations in male mice after chronic exposure to microwave radiation.

Male C3H mice were exposed to 100 W m-2 of 2.45 GHz continuous-wave microwave radiation for 6 h per day for a total of 120 h over an 8-week period. The exposure level was chosen so that the specific energy absorption rate (SAR) would be approximately equal to the level of 4 W kg-1 which is considered by a number of organizations to be a threshold for adverse biological effects. At the end of the treatment period the mice were mated with a different group of (C3H x 101) F1 hybrid females each week for the following 8 weeks. There was no significant reduction in pregnancy rate, preimplantation survival or postimplantation survival in the exposed group compared to sham-exposed controls. At the end of the mating period a cytogenetic analysis was carried out of meiotic chromosome preparations of testicular tissue, thus sampling cells that were stem cell spermatogonia during the treatment regime. The results showed no difference in the frequency of reciprocal translocations between the sham and treated groups, or in the frequency of cells with autosome or sex chromosome univalents. Low levels of fragments and exchanges were found in both groups. It is concluded that there is no evidence in this experiment to show that chronic exposure of male mice to 2.45 GHz microwave radiation induces a mutagenic response in male germ cells. This conclusion is in agreement with the observations of Berman et al. (1980), who reported a lack of male germ cell mutagenesis after repetitive or chronic exposure of rats to 2.45 GHz.

Animals↗
PubMed1988

Correlations between gingival crevicular fluid enzymes and the subgingival microflora.

Bacteroides gingivalis is a Gram-negative micro-organism implicated in the pathogenesis of adult periodontitis and producing relatively large amounts of specific enzymes. In the present study, subgingival samples taken from adults with moderate periodontitis were examined for the presence and relative amounts of enzymatic activity toward certain substrates. Enzyme levels were then correlated with clinical periodontal indices and microbiological analysis of subgingival plaque, including darkfield microscopy for bacterial morphotypes and immunofluorescence microscopy for B. gingivalis and Bacteroides intermedius. The results of this study indicate a significant positive correlation between levels of enzyme capable of degrading N-benzoyl-D,L-arginine-beta-naphthylamide hydrochloride, and subgingival B. gingivalis (r = 0.55). There was a much lower correlation coefficient between this enzyme activity and subgingival B. intermedius (r = 0.26). Statistically significant (p less than 0.01) positive correlations were also demonstrated between total bacterial cell counts and levels of enzymatic activity against N-benzoyl-D,L-arginine-beta-naphthylamide hydrochloride (r = 0.76), N-carbobenzoxy-glycyl-glycyl-L-arginine-beta-naphthylamide hydrochloride (r = 0.72), and glycyl-L-proline-4-methoxy-beta-naphthylamide hydrochloride (r = 0.72), and glycyl-L-proline-4-methoxy-beta-naphthylamide hydrochloride (r = 0.69). There were significant differences in the levels of these three enzymatic activities between sites exhibiting various degrees of clinical severity of gingival inflammation and harboring various proportions of B. gingivalis. The data from this study indicate that measurement of specific enzymatic activities in subgingival samples can be useful in the diagnosis of B. gingivalis-associated periodontitis.

Aged↗
PubMed1988

Microbiological and immunological studies of adult periodontitis in patients with noninsulin-dependent diabetes mellitus.

The subgingival microflora and serum antibody response was examined in periodontitis patients with noninsulin-dependent diabetes mellitus (NIDDM), impaired glucose tolerance (IGT), and normal glucose tolerance (NGT). The predominant cultivable microflora was determined for subgingival plaque sampled from two deep periodontal pockets in each of eight adult periodontitis patients with NIDDM. Indirect immunofluorescence for Bacteroides intermedius, Bacteroides gingivalis, and Haemophilus actinomycetemcomitans was used to examine these same samples as well as 186 additional subgingival plaque samples from 47 patients with moderate to severe generalized periodontitis including 25 subjects with NIDDM, six subjects with IGT, and 16 subjects with NGT. Serum antibody levels to 13 microorganisms including seven oral bacterial species and one nonoral control species were measured by enzyme-linked immunosorbent assays (ELISA) in 377 subjects including 84 normal subjects without periodontal disease, 112 normal subjects with periodontitis, 19 periodontally normal subjects with IGT, 65 periodontitis patients with IGT, 15 periodontally normal subjects with NIDDM, and 82 periodontitis patients with NIDDM. Three hundred eighty-two bacterial isolates were recovered from the eight patients. B. intermedius was the most frequently isolated microorganism constituting 16% of the total isolates followed by Wolinella recta and B. gingivalis, which each accounted for 13% of the total. Streptococcus sanguis was the most prevalent microorganism, which was found in 75% of the sites. Subgingival plaque samples examined by immunofluorescence demonstrate a high prevalence of black-pigmented Bacteroides and suggest that the proportion of B. gingivalis but not B. intermedius is higher in NIDDM with periodontitis than in other groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Usefulness of subtraction radiography in the evaluation of periodontal therapy.

Subtraction radiography, a sensitive and accurate technique for identifying alveolar crestal change from standardized pairs of radiographs, is useful in monitoring periodontal therapy. One half of the radiographs were found to be appropriate for subtraction analysis using present technology for taking standardized radiographs. The criterion for usability was identical interpretation of subtraction images made in duplicate from a pair of radiographs. A set of radiographs was analyzed by subtraction radiography as well as by measurement of alveolar bone-crest height. Subtraction radiography was found to be more sensitive in detecting change. Whereas 53% pairs of radiographs showed a change on subtraction radiography, only 14% showed a change in crest height. Comparison of change by subtraction radiography and probing attachment level showed an overall correlation. Since these two measures assess different aspects of the periodontium, perfect correlation was not expected.

Alveolar Process↗