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Biomedical subjects

R Duguid

Publications and source records attributed to R Duguid.

At least 19 recordsLinked to original sources
PubMed2000

The admission of students to UK Dental Schools--recent trends (1983-1998).

Details of student applications and admissions to UK Dental Schools from 1983 to 1998 have been recorded and analyzed. Trends observed include a rise in the proportion of female dental students, a drop in real numbers of male dental students, a recent drop in the proportion of mature students and an increase in the number of EU and overseas entrant dental students. Some implications of these and other factors on workforce planning in the UK are discussed.

Adult↗
PubMed1997

Student drop-out from UK dental schools.

OBJECTIVE: To determine the level of student drop-out from UK dental schools and to establish if drop-out is increasing, remaining steady or decreasing. DESIGN: Retrospective analysis of data from the University Statistical Record. SETTING: UK dental schools 1989-1994. SUBJECTS AND METHODS: The data covered all dental students entering and leaving dental schools during the relevant time period. RESULTS: The drop-out rate from UK dental schools between 1989 and 1994 ranged from 8.4% to 16.8% and is equivalent to the output of two to three medium-sized dental schools. Drop-out rate was higher in the three most recent years studied (1992-1994; 14.8%) than in the three earliest years studied (1989-1991; 10.6%). CONCLUSIONS: Student drop-out is a significant and increasing problem for UK dental schools. Unless controlled, it will result in fewer dentists qualifying in the UK and exacerbate shortages in qualified dentists that may occur in future years.

Dentistry↗
PubMed1997

The effect of fluoride on Streptococcus sanguis 7863 IgA1 protease production and activity.

Fluoride was found to affect the production of the bacterial IgA1 protease but to have no effect on IgA1 protease activity. The concentrations of fluoride that do affect Streptococcus sanguis growth and IgA1 protease production are higher than those normally seen in vivo under normal circumstances. The concentrations of fluoride in dental plaque following use of a fluoride rinse or dentifrice would be sufficient to reduce Strep. sanguis IgA1 protease production.

Cariostatic Agents↗
PubMed1996

The effects of adding chlorhexidine and polyhexamethylene bisguanide to a light-cured periodontal dressing material.

The effect of adding two bisguanide antimicrobial agents (chlorhexidine and PHMB) on some physical properties of the light-cured periodontal dressing material Barricaid are reported. The physical properties tested were elastic modulus, initial and 10 min recovery strains, and tear stress. The addition of both chlorhexidine and PHMB solutions reduced the elastic modulus as did water. The addition of PHMB to Barricaid produced greater initial recovery in the strain test than either the addition of chlorhexidine or water, but there were no differences between the treatments after 10 min. Tear stress was also reduced by the addition of water and the chlorhexidine and PHMB solutions. These results suggest that as far as the physical properties of Barricaid are concerned the addition of the antimicrobial agent PHMB had no long-term advantages over chlorhexidine.

Anti-Infective Agents, Local↗
PubMed1996

The antimicrobial activity of endodontic sealers to anaerobic bacteria.

The effect of five root canal sealers and two root canal dressing materials on the growth of three anaerobic bacteria associated with endodontic infections was determined using the agar diffusion inhibitory test. Samples of the following endodontic sealers (Apexit, Ketac-Endo, Roth Sealer, Sealapex and Tubliseal) and root canal dressing materials (Pulpdent and Root-cal) were incubated for 48 h with the following anaerobic bacteria: Capnocytophaga ochracea, Porphyromonas gingivalis and Peptostreptococcus micros. Statistically significant zones of bacterial growth inhibition for all the bacteria tested were observed in descending order of antimicrobial activity: Roth Sealer, Ketac-Endo, Tubliseal, Apexit and Sealapex. Root-cal and Pulpdent also showed statistically significant antimicrobial activity, but only to Capnocytophaga ochracea, not to the other two bacteria tested, with Pulpdent being the least active.

Bacteria, Anaerobic↗
PubMed1994

Recent changes in UK dental school admissions.

Admissions to UK dental schools through the UCCA system have been studied for the 10 years from 1983 to 1993. Over this period the number of home students admitted has dropped from 885 in 1983 to 776 in 1993 (a 12% decrease) while the number of overseas students admitted has risen from 34 to 93. At the same time there has been noticeable increase in the numbers of mature home students admitted, with the proportions of over-21s, over-25s and over-30s all increasing between 1983 and 1993. The proportion of female dental students admitted has also risen (in 1993 49% of home students and 57% overseas students). The average A-level score of entrant students has varied little over this period, and remains high compared with most other subjects studied at university. Most of the changes in dental student admissions reported here are likely to reduce the pool of full-time dental manpower available to the country in future years.

Adult↗
PubMed1989

Applications and admissions to UK dental schools through UCCA: 1968-1987.

Applications and admissions to UK dental schools through the UCCA system have been analysed for the 20-year period from 1968 to 1987. Applications rose from 1225 in 1968 to a peak of 3065 in 1974. By 1987, applications had fallen to 2050, 67% of the peak number. The ratio of male:female applicants has declined from 4:1 in 1968 to 1.6:1 in 1987. The number of dental students accepted through UCCA has varied much less during the 20-year period, rising from 831 in 1968 to a peak of 989 in 1980, and falling back to 893 in 1987. The number of dental students admitted to dental schools through UCCA in the 4 years including and after 1984 was 7.4% less than in the 4 years prior to 1984. This suggests that the 1984 cut of 10% was not fully achieved. The ratio of male:female students admitted has fallen from 3.4:1 in 1968 to 1.4:1 in 1987. In every year studied, the male:female ratio of UCCA applicants was higher than for accepted dental students. This could suggest that female applicants to dental school have higher academic or personal qualities than their male counterparts.

Educational Measurement↗
PubMed1987

The effect of arginine on in-vitro acid production by the oral bacterium Streptococcus mutans 10449 in various concentrations of glucose.

Acid production was measured both with constant pH and with the pH being allowed to fall. Under both conditions 10 mM arginine reduced it. There was also evidence that arginine reduced the rate of uptake of glucose by the bacterium. Thus arginine may affect the rate of glucose transport or catabolism by Strep. mutans 10449, and has more than a simple buffering effect on these cultures.

Acetates↗
PubMed1986

Measurements of ionic fluoride in milk.

Procedures used for measuring ionic fluoride in both human and cow's milk have been investigated. A number of factors were found to affect fluoride ion measurements in milk samples including time, stirring and the method of cleaning the fluoride electrode. Following these investigations a procedure was developed for estimating ionic fluoride in milk. Human milk collected from a fluoridated area (Newcastle-upon-Tyne) was found to contain significantly more ionic fluoride (0.065 ppm) than human milk from mothers in a non-fluoridated area (Dundee, 0.035 ppm).

Animals↗
PubMed1985

In-vitro acid production by the oral bacterium Streptococcus mutans 10449 in various concentrations of glucose, fructose and sucrose.

At intermediate and high concentrations, the results with the sugars were similar, with lactic acid as the main end product. Over 4 h, the pH fell from approx. 7 to 4. At low monosaccharide concentrations (2 mM glucose, 2 and 5 mM fructose), after an initial pH drop and period of lactic-acid production, evidence of pH rise and lactic-acid consumption were noted. This did not happen when sucrose was added to the bacteria. There was evidence of a heterolactic-acid fermentation pattern at low-sugar concentrations, lactic, acetic and formic acids being produced in similar amounts. The results suggest that, when low-sugar concentrations are present in dental plaque, Strep. mutans is capable of consuming previously-formed lactic acid.

Acetates↗
PubMed1985

Inhibition of [3H]-thymidine uptake in human gingival fibroblasts by extracts from human dental plaque, oral bacteria of the Streptococcus and Actinomyces species.

Extracts from human dental plaque, Streptococcus mutans, Streptococcus salivarius, Streptococcus faecalis, Streptococcus sanguis, Actinomyces israelli and Actinomyces odontolyticus inhibited [3H]-thymidine uptake by primary human gingival fibroblast cell lines as previous work has shown in respect of HeLa cells. The results show that a variety of oral bacteria, not usually considered to be periodontal pathogens, elaborate factors that adversely affect fibroblasts.

Actinomyces↗
PubMed1983

Acid phosphatase activity of human gingival fibroblasts measured using a simultaneous coupling semi-permeable membrane technique.

Acid phosphatase activity has been measured in cultured human gingival fibroblasts using a validated histochemical simultaneous coupling semi-permeable membrane technique. The histochemical reaction was linear over a three hour incubation period and had a pH optimum of 5.0. The activity was not increased by prior exposure to hypotonic acetate buffer and was inhibited by fluoride and molybdate but not by formaldehyde. These results indicate that the semi-permeable membrane technique described may be used for observing and measuring acid phosphatase activity in cultured fibroblasts. From results obtained using inhibitors, it appears that in these cells most of the acid phosphatase observed is lysosomal. The absence of any activation of activity following pre-incubation with hypotonic buffer indicates that the method is not suitable for monitoring lysosomal membrane function.

Acid Phosphatase↗
PubMed1983

Copper-inhibition of the growth of oral streptococci and actinomyces.

Copper ions were found to inhibit the rate of growth in broth culture of Streptococcus mitis, Streptococcus mutans, Streptococcus salivarious, Streptococcus sanguis, Actinomyces viscosus and Actinomyces naeslundii. In all cases, 10(-3) M copper inhibited the rate of growth, whereas 10(-4) M and lower concentrations had little or no effect. At the concentrations used in mouthwashes one mode of action of copper ions is to reduce the rate of growth of oral bacteria in vitro.

Actinomyces↗
PubMed1982

The effect of extracts from human dental plaque, oral streptococci and actinomyces bacteria on HELA cell growth, [3H]-thymidine uptake and 51Cr release.

Dialysed extracts from dental plaque and a number of species of oral streptococci and actinomycetes have been investigated for their effects on cell growth, [3H]-thymidine uptake and 51Cr release from HeLa cell cultures. Eight of the 15 extracts inhibited cell growth and all but one inhibited [3H]-thymidine incorporation. None of the extracts stimulated 51Cr release from prelabelled cells. These results suggest that many of the species of streptococci and actinomyces found in the mouth and in dental plaque are capable of producing high mol. wt substances that interfere with HeLa cell cultures by inhibiting [3H]-thymidine uptake and DNA synthesis but do not affect the degree of intactness of the external cell membrane.

Actinomyces↗
PubMed1982

Studies on uterine tract infections and the IUCD with special reference to actinomycetes.

Since the advent of the plastic IUCD, an increasing number of patients with clinical pelvic actinomycosis have been reported in the literature and in a very much larger number of women, actinomycetes have been identified in cervical smears, either by Papanicolaou stain or specific immunofluorescence. After a 3-year study, we have concluded that actinomycetes can readily be cultured when the growth of more rapidly growing anaerobes is inhibited by metronidazole and anaerobic culture is continued for up to 14 days. We consider that actinomycetes form part of a polymicrobial anaerobic infestation developing in the presence of a foreign body. The organisms are found almost exclusively in women who have used all-plastic IUCDs for a long term and, from a continuing study, it is apparent that most disappear rapidly when the plastic device is removed or replaced by a copper device. Significant symptomatic evidence of infection is found in a small proportion of patients who are actinomycete-positive.

Actinomycetales↗
PubMed1982

Relationship between restorations and the level of the periodontal attachment.

Two hundred and forty stained extracted teeth with a restoration on one proximal surface and with no restoration on the opposite surface were investigated for the position and quality of the restoration and the position of the periodontal attachment. Only 27% of restorations were of good quality, 60% had overhangs and 13% deficiencies. The mean difference in loss of periodontal attachment (LOA) between the two surfaces for all teeth was 0.36 mm when the distance from the cemento-enamel junction to the periodontal membrane on the unrestored surfaces was subtracted from that on the restored surfaces. If allowance is made for those restorations located apical to the cemento-enamel junction, the LOA difference was 0.18 mm.

Dental Restoration, Permanent↗