Biomedical subjects

W A Coulter

Publications and source records attributed to W A Coulter.

At least 19 recordsLinked to original sources

PubMed2005

Differential display analysis of Porphyromonas gingivalis gene activation response to heat and oxidative stress.

BACKGROUND/AIMS: The etiologic relationship between periodontitis and Porphyromonas gingivalis is attributed to the ability of the organism to express a variety of virulence factors, many of which are cell surface components including lipopolysaccharide and arginine-specific cysteine proteases (Arg-gingipains, RgpA, and RgpB). P. gingivalis responds to the stress of rapid elevation in temperature by activating a set of genes to produce heat shock proteins that mediate the effects of sudden changes in environmental temperatures by repairing or eliminating cellular proteins denatured by that stress. METHODS: We used restriction fragment differential display (RFDD) to identify and measure the genes expressed by surrogates of environmental stresses, heat and oxidative stress. The results were then confirmed using quantitative reverse-transcription polymerase chain reaction. RESULTS: We selected 16 genes differentially induced from over 800 total expression fragments on the RFDD gels for further characterization. With primers designed from those fragments we found that a + 5 degrees C heat shock caused a statistically significant increase in expression compared 12 of 18 untreated genes tested. The exposure of P. gingivalis to atmospheric oxygen resulted in statistically significant increases in five of the target genes. These genes are likely involved in transport and synthesis of components of the lipopolysaccharide biosynthetic pathway important in anchoring the Arg-gingipains required for virulence-related activities. CONCLUSION: These results emphasize the need for studies to measure the coordinated responses of bacteria like P. gingivalis which use a multitude of interrelated metabolic activities to survive the environmental hazards of the infection process.

Adhesins, Bacterial↗

PubMed2005

In vitro susceptibility of oral Candida to seven antifungal agents.

The in vitro susceptibility of 618 Candida isolates to fluconazole, itraconazole, voriconazole, ketoconazole, miconazole, amphotericin B, and nystatin was determined. The isolates were obtained from 559 patients who had attended the UK dental hospital departments in Cardiff, Belfast, Glasgow or London. Antifungal susceptibility was assessed using a broth microdilution method following the National Committee for Clinical Laboratory Standards (NCCLS) M27-A guidelines. The majority of the test strains were C. albicans (n = 521) with few of these being resistant to fluconazole (0.3%). A low incidence of fluconazole resistance (0-6.8%) was similarly evident with all non albicans species (Candida glabrata, 5 of 59 resistant; Candida krusei, 0 of 7 resistant; Candida tropicalis, 0 of 13 resistant; Candida parapsilosis, 0 of 12 resistant; other Candida species, 0 of 6 resistant). Voriconazole, ketoconazole, and miconazole also revealed high activity against both C. albicans and non albicans isolates, and 23.7% of C. glabrata isolates were found to be resistant to itraconazole. There was little difference in the antifungal susceptibilities of Candida isolated from patients who had a history of previous antifungal therapy compared with those who had not received antifungal treatment. In summary, this surveillance study of antifungal susceptibility of oral candidal isolates in the UK, through the collaboration of four dental hospitals, demonstrates that oral Candida species have a high level of susceptibilities to a range of antifungal agents.

Amphotericin B↗

PubMed2004

The incidence of occupational exposures among students in four UK dental schools.

OBJECTIVES: To evaluate: the incidence of occupational exposures (OE) to patient body fluids among a sub-group of dental students; the rate of reporting of incidents; and the association of various factors. DESIGN: Multicentre retrospective analysis. SETTING: Four UK dental schools in 2000. SUBJECTS: Dental students from 4 UK schools completed a confidential questionnaire at the end of the clinical years of their undergraduate course. RESULTS: The response rates ranged from 71-100%, showing that 12-40% of students among the schools had experienced one or more OE incidents since starting their course. No statistically significant association was found between OE incidence and age, sex, dominant hand or time of day; most OE occurred with handling of local anaesthetic syringes. 61-78% of incidents were penetrative in nature, and 28-53% of students had not reported their last OE. OE incidence was associated with school, year of course, presence of patient and presence of an assistant. There were substantial differences in the numbers of students experiencing OE among the schools. CONCLUSIONS: Within the limitations of the survey and variations within the clinical activity of schools, it may be seen that improvements are needed in some schools to reduce cross-infection risks, and increase reporting of incidents. Suggestions are offered which may increase the safety of dental treatment.

Anesthetics, Local↗

PubMed2004

Autoclave use in dental practice in the Republic of Ireland.

AIMS: To assess by postal questionnaire, cross-infection control methods, especially sterilisation procedures, of 700 general dental practitioners in the Republic of Ireland, and to biologically monitor steam pressure sterilisers or autoclaves in their practices. MAIN OUTCOME MEASURES: Methods of instrument cleaning and sterilisation, autoclave efficacy. RESULTS: A response rate of 40% with all, except one practitioner, using steam sterilisation. 49% also reported the use of chemical sterilisation with a quarter of these using glutaraldehyde. However, instrument soaking time varied greatly from 2.5 minutes to 74 hours. Methods of instrument cleaning prior to autoclaving were as follows: scrubbing by hand 41.5%, ultrasonic cleaning 7.0%, combination of both 50%. 52.9% of the respondents did not autoclave their dental handpieces and only 44.7% disinfected impressions before sending them to the laboratory. The autoclaves of thirty practitioners (11.3%) did not pass the initial biological test. Following counselling about possible causes of failure, four autoclaves (1.5%) failed a repeat biological test. However, seven practitioners did not return the repeat biological test. CONCLUSIONS: Some aspects of recommended cross-infection control procedures are well adhered to, e.g. instrument cleaning, but further education is required in certain key areas, in particular the use of chemical sterilisation, dental handpiece autoclaving and impression disinfection. There is also a need to increase awareness of the importance of routine autoclave servicing and calibration, along with validation and monitoring.

Creutzfeldt-Jakob Syndrome↗

PubMed2001

Autoclave performance and operator knowledge of autoclave use in primary care: a survey of UK practices.

Changes in the delivery of health care have increased the demand for minor surgical and screening procedures in general practice. This has increased the risk of cross-infection with blood-borne viruses and the demand for sterile instruments. The aim of this study was to investigate the knowledge and training of medical personnel in England and Wales on aspects of autoclave use, and to test the effectiveness of their practice autoclaves. An anonymous postal questionnaire and autoclave performance survey using biological indicators was made of 700 general medical practitioners selected at random from FHSA lists from 12 Health Authorities in England and Wales. The overall response rate was 53.1% (N= 372) comprising 10% general practitioners and 90% practice nurses. Eighty-two percent of respondents used autoclaves with a mean age of 2.5 years, of which 91% had been serviced in the past year. While 35% of respondents made daily observation of gauges, 19% did not routinely monitor autoclave effectiveness. Six autoclaves failed to sterilize the spore test ampoules. Fourteen percent of respondents did not autoclave instruments after every patient. Only 33.1% reported wearing gloves during minor operations. Fifty five percent had training in cross-infection prevention. It was concluded that although there has been improvement in instrument decontamination procedures in general practice compared with previous surveys, further education of medical practitioners and practice nurses in the use of autoclaves and infection prevention and control is indicated. The failure of 2% of the autoclaves to kill spores suggests the need for increased monitoring of autoclave performance. Two-thirds of practitioners exposed themselves to increased risk of infection by carrying out minor surgery without the protection of gloves.

Cross Infection↗

PubMed2001

The influence of antifungal drugs on virulence properties of Candida albicans in patients with diabetes mellitus.

OBJECTIVE: This study investigated the influence of nystatin and fluconazole on virulence properties of Candida albicans. STUDY DESIGN: A total of 108 diabetic patients participated in the study. Eighty-eight patients had clinical oral candidosis. Drug therapy was given at 6 hourly intervals for nystatin or daily with fluconazole for a maximum of 2 weeks. Adhesion of C albicans to buccal epithelial cells was determined by using an autologous adhesion assay prospectively over 6 months. Phospholipase production was estimated by using an agar plate method. The data analysis included a paired Student t test and calculation of correlation coefficients. RESULTS: Unlike nystatin, treatment with fluconazole reduced the ability of C albicans to colonize the buccal mucosa for up to 8 weeks after the treatment. Patients without clinical signs of oral candidosis had significantly fewer C albicans isolates producing phospholipase than did patients with oral candidosis. Treatment with fluconazole, but not nystatin, reduced the production of phospholipase from C albicans oral isolates in patients with diabetes mellitus. CONCLUSIONS: In addition to being antifungal, fluconazole alters phospholipase production, modifies buccal epithelial cells, and reduces adhesion of C albicans to human buccal epithelial cells for up to 8 weeks posttreatment in diabetic patients with oral candidosis.

Analysis of Variance↗

PubMed2001

Identification of Candida dubliniensis, based on ribosomal DNA sequence analysis.

Differentiation of Candida albicans and the recently described C. dubliniensis has proven difficult due to the high degree of phenotypic similarity of these species. The present study examines sequence variations in the ribosomal DNA (rDNA) intergenic transcribed spacer (ITS) regions of C. albicans (n = 5) and C. dubliniensis (n = 7) strains, with a view to identifying sequence differences that would enable consistent differentiation of these two species by restriction fragment length polymorphism (RFLP) analysis. The ITS1 and ITS2 regions, together with the entire 5.8S rRNA gene of the strains, were amplified by the polymerase chain reaction (PCR), using primers ITS1 and ITS4, PCR products from both C. albicans and C. dubliniensis were of similar size (around 540 bp); however, sequence analysis revealed over 20 consistent base differences between the products of the two species. On the basis of sequence variation, the restriction enzyme MspA1 I was selected and used to differentiate the PCR products of C. albicans and C. dubliniensis by RFLP analysis. MspA1 I yielded two discernible fragments from C. albicans PCR products, whilst those from C. dubliniensis appeared undigested, thereby providing an approach to differentiate the two species.

Candida↗

PubMed2000

Design, characterisation and preliminary clinical evaluation of a novel mucoadhesive topical formulation containing tetracycline for the treatment of periodontal disease.

This study describes the formulation, characterisation and preliminary clinical evaluation of mucoadhesive, semi-solid formulations containing hydroxyethylcellulose (HEC, 1-5%, w/w), polyvinylpyrrolidine (PVP, 2 or 3%, w/w), polycarbophil (PC, 1 or 3%, w/w) and tetracycline (5%, w/w, as the hydrochloride). Each formulation was characterised in terms of drug release, hardness, compressibility, adhesiveness (using a texture analyser in texture profile analysis mode), syringeability (using a texture analyser in compression mode) and adhesion to a mucin disc (measured as a detachment force using the texture analyser in tensile mode). The release exponent for the formulations ranged from 0.78+/-0.02 to 1. 27+/-0.07, indicating that drug release was non-diffusion controlled. Increasing the concentrations of each polymeric component significantly increased the time required for 10 and 30% release of the original mass of tetracycline, due to both increased viscosity and, additionally, the unique swelling properties of the formulations. Increasing concentrations of each polymeric component also increased the hardness, compressibility, adhesiveness, syringeability and mucoadhesion of the formulations. The effects on product hardness, compressibility and syringeability may be due to increased product viscosity and, hence, increased resistance to compression. Similarly, the effects of these polymers on adhesiveness/mucoadhesion highlight their mucoadhesive nature and, importantly, the effects of polymer state (particularly PC) on these properties. Thus, in formulations where the neutralisation of PC was maximally suppressed, adhesiveness and mucoadhesion were also maximal. Interestingly, statistical interactions were primarily observed between the effects of HEC and PC on drug release, mechanical and mucoadhesive properties. These were explained by the effects of HEC on the physical state of PC, namely swollen or unswollen. In the preliminary clinical evaluation, a formulation was selected that offered an appropriate balance of the above physical properties and contained 3% HEC, 3% PVP and 1% PC, in addition to tetracycline 5% (as the hydrochloride). The clinical efficacy of this (test) formulation was compared to an identical tetracycline-devoid (control) formulation in nine periodontal pockets (>/=5 mm depth). One week following administration of the test formulation, there was a significant improvement in periodontal health as identified by reduced numbers of sub-gingival microbial pathogens. Therefore, it can be concluded that, when used in combination with mechanical plaque removal, the tetracycline-containing semi-solid systems described in this study would augment such therapy by enhancing the removal of pathogens, thus improving periodontal health.

Acrylic Resins↗

PubMed2000

Quantitation of Bacteroides forsythus in subgingival plaque comparison of immunoassay and quantitative polymerase chain reaction.

Our objective was to compare three methods (enzyme-linked immunosorbent assay [ELISA], endpoint and quantitative polymerase chain reaction [E-PCR and Q-PCR]) for detection and quantitation of Bacteroides forsythus in 56 plaque samples from seven subjects with progressive periodontal disease. Samples collected in buffer were pelleted and resuspended in 500 microl of water. Fifty microl aliquots were removed for an ELISA performed on bacteria or plaque immobilized on 96-well plates and probed with B. forsythus specific antibody. An occurrence of 3.7+/-0.6 x 10(4) or more bacteria were detected by ELISA in pure culture; 26 of 54 plaque samples were positive, two samples could not be analyzed. Samples for PCR were autoclaved for 10 min prior to use. The detection level of E-PCR using primers specific for B. forsythus 16S rRNA was 200 cells and 42 out of 56 samples were positive based on ethidium bromide stained agarose gels. Q-PCR using the same primers combined with a nested fluorescent oligonucleotide probe detected 10+/-0.32 bacteria in pure culture; 43 of 56 plaque samples were positive. The ELISA and Q-PCR obtained identical results with 36 of the 54 samples assayed; there were one false positive and 17 false negative ELISA results using Q-PCR as standard. The positive proportions of plaque samples were almost the same for E-PCR and Q-PCR. We conclude that the PCR methods are more appropriate for a multicenter study because of greater sensitivity and convenience of sample transportation from clinics to a central laboratory.

Bacteroides↗

PubMed2000

Isolation of C. dubliniensis from insulin-using diabetes mellitus patients.

The identification of the novel candidal species, C. dubliniensis, from oral swab studies of HIV-seropositive and -seronegative individuals has led to speculation that such a species may also reside in the oral cavity of other patient groups. In this study involvement of the newly described species, C. dubliniensis, was investigated in oral carriage and disease in 414 insulin-using diabetes mellitus patients. Seventy-seven percent of the diabetic patients carried candidal species in the oral cavity. C. albicans was the most commonly identified candidal species. This was followed by C. dubliniensis, which was isolated on 64 occasions. Colonisation with multiple candidal species was common, and C. dubliniensis was present in both carriage and disease states. Seven patients without signs of oral disease had C. dubliniensis isolated as the sole candidal species, while the same species was associated with various forms of oral candidosis in six patients.

Candida↗

PubMed2000

Prevalence of periodontal pathogens in localized and generalized forms of early-onset periodontitis.

The primary objectives of this study were to investigate the prevalence of 8 putative periodontal pathogens in subjects with early-onset periodontitis (EOP) and to evaluate the microbial differences between localized and generalized forms of this periodontal disease condition. Thirty-one females and 11 males with a mean age of 30.3 (s.d. 4.0) years were examined. Seventeen subjects had generalized (GEOP) and 25 had localized early-onset periodontitis (LEOP). Subgingival plaque samples were assayed using PCR which provided subject prevalence data for the pathogens; Bacteroides forsythus 78.6%, Treponema denticola 88.1%, Actinobacillus actinomycetemcomitans 19.0%, Porphyromonas gingivalis 16.7%, Prevotella intermedia 40.4%, Prevotella nigrescens 61.9%, Eikenella corrodens 42.3% and Campylobacter rectus 92.8%. Only 3 healthy sites harbored one or more of these periodontal pathogens. Seven of the 8 subjects positive for A. actinomycetemcomitans had LEOP. P. intermedia was present in 58.8% of GEOP compared with 28% of LEOP subjects (p=0.046). At 82.4% of GEOP sites P. nigrescens was present while this bacteria was detected at 52% of LEOP (p=0.044). P. gingivalis was isolated from 22.6% of females but no male subjects (p=0.084). C. rectus was recovered from all female subjects compared to 72.7% of males (p=0.014). A. actinomycetemcomitans (37.5%) and C. rectus (86.5%) were more frequently identified in non-smokers compared to 7.6% and 68.8% of smokers, respectively (p <0.05). Microbial associations coincided with the clinical division of the cases into LEOP and GEOP in 83% of the subjects.

Adolescent↗

PubMed2000

Factors affecting the adhesion of Candida albicans to epithelial cells of insulin-using diabetes mellitus patients.

This study investigated the influence of the carbon source of the growth medium, strains of Candida albicans and source of epithelial cells, and the influence of smoking and gender, on the adhesion of C. albicans to epithelial cells from insulin-using diabetic patients. Adhesion was determined by an autologous adhesion assay with exfoliated buccal or palatal epithelial cells and one strain of C. albicans isolated from each patient. The type strain CBS 562 was also used. Glucose or sucrose were used as the predominant carbon sources of the growth medium. The autologous strain of C. albicans adhered selectively to the oral mucosa of diabetic patients. Palatal epithelial cells retained significantly more C. albicans in vivo and adhesion was influenced by the availability of sugars in the growth medium and the strain of C. albicans.

Candida albicans↗

PubMed1999

Improving and monitoring autoclave performance in dental practice.

The sterilisation of instruments is central to the infection control process in the dental surgery, with the autoclave being most frequently used for this process. For effective operation, among other factors, it is essential that the autoclave is loaded correctly and tested regularly to ensure that it is operating at a temperature and pressure which will kill all micro-organisms. Biological indicators are another method of verifying the sterilisation process, since the sterilisation of the bacterial spores within the test ampoule provides a guarantee that sterilising conditions have been achieved.

Dental Equipment↗

PubMed1999

Oral candidal carriage and infection in insulin-treated diabetic patients.

AIM: To evaluate candidal load and carriage of candidal species in 414 insulin-treated diabetes mellitus patients with and without clinical signs of infection. Host factors that could influence candidal load in diabetic patients with oral candidosis were also investigated. METHODS: Candidal species were recovered from 414 insulin-treated diabetes mellitus patients attending two hospital diabetic clinics, using an oral rinse technique. RESULTS: Seventy-seven per cent of diabetic patients carried Candida species in their oral cavity, with C. albicans being the species most frequently isolated. C. dubliniensis was found for the first time in this patient group. Forty per cent of patients colonized with candidal species had no clinical signs of oral candidosis. Where oral candidosis was present, erythematous candidosis was the most common clinical presentation. Candidal load was not associated with age, sex or glycaemic control. However, it was significantly increased in those patients who were tobacco smokers, and non-significantly increased in those patients who wore dentures, or who had clinical signs of oral candidosis. CONCLUSION: The epidemiology of oral candidal carriage and infections in diabetic patients is complex and includes species which have not been previously reported in this group of patients. The development of oral candidosis in insulin-treated diabetes mellitus patients is not the result of a single entity, but rather, a combination of risk factors.

Analysis of Variance↗

PubMed1998

Nested primers improve sensitivity in the detection of Helicobacter pylori by the polymerase chain reaction.

To investigate potential routes of spread of infection by the polymerase chain reaction (PCR) it is important that the technique is effective in the types of specimen to be investigated. To establish the limits of detection of Helicobacter pylori by PCR in clinical material from the gastric mucosa, faeces, dental plaque and oral rinses, samples were seeded with known numbers of bacteria. DNA extraction was followed by amplification with primers from the urease C gene. Nested primers were used to amplify the PCR product which was detected using a digoxigenin-labelled probe. Faeces or plaque inhibited the single reaction 10(2)-10(6) fold. A second amplification using nested primers and probing increased the sensitivity to a level similar to that obtained with pure culture. This method is potentially useful with less likelihood of false negative results when trying to detect H. pylori by PCR in highly contaminated, clinical material.

DNA Primers↗

PubMed1998

Autoclave performance and practitioner knowledge of autoclave use: a survey of selected UK practices.

OBJECTIVE: It is essential that the dental surgery autoclave be tested regularly to ensure that it is operating at a temperature and pressure that will kill all microorganisms. The aims of this study were to investigate the knowledge of general dental practitioners on aspects of autoclave use, to examine their autoclaving routines, and to test the effectiveness of the sterilization cycle of their practice's autoclave. METHOD AND MATERIALS: A 35-question questionnaire was distributed to 840 dental practitioners in the United Kingdom. They were also sent three spore test ampules with details of their function and instructions on their use. The practitioners were asked to use the spore test ampules in their own practice's autoclave and to return these for testing. RESULTS: Four hundred one questionnaires and associated spore test ampules were returned for analysis, a 47.7% response rate. Eight practice autoclaves (2.0%) failed to sterilize the spores. These practices were offered a retest following counseling. A total of 77.8% of respondents had received formal training in infection control. Of the 71.3% of respondents who stated that they check the performance of their autoclave routinely, 31.5% use a chemical strip every cycle, 17.5% use it once per day, and 30.4% use it once per week. However, only five respondents (1.2%) use a spore test; two of these respondents use it every cycle, one once per day, and two once per week. CONCLUSION: Further education of practitioners may be necessary to enhance their awareness of the need for routine checking of autoclave effectiveness.

Dental Equipment↗

PubMed1997

Oral shedding of herpes simplex virus type 1: a review.

Herpes simplex virus type 1 (HSV-1) and, to a lesser extent, type 2 (HSV-2) are the aetiological agents of recrudescent herpes labialis (RHL). The available literature on patterns of HSV-1 shedding into the oral cavity at the prodromal stage of disease, during recrudescences and also during asymptomatic periods, is reviewed, as are the potential sources of virus and the known trigger factors leading to viral reactivation. Attention is given to the methodologies in use for the detection of HSV-1 and the relevance to the risk of cross-infection in surgery. This review also discusses the increase in incidence of HSV-1 genital infections and the significance of salivary inhibitors of the herpes simplex type 1 virus.

Anti-Infective Agents↗

PubMed1997

Detection of herpes simplex virus type 1 shedding in the oral cavity by polymerase chain reaction and enzyme-linked immunosorbent assay at the prodromal stage of recrudescent herpes labialis.

Recrudescent herpes labialis (RHL) is a disease caused by herpes simplex virus (HSV), predominantly type 1 (HSV-1). We have monitored HSV-1 shedding in the oral cavity by polymerase chain reaction (PCR) and enzyme-linked immunosorbent assays (ELISA) using digoxigenin-labeled primers designed to amplify a 278 bp segment of the HSV-1 UL 42 region. Prodromal RHL was confirmed by thermographic imaging in 22 patients. Infectious virus was not detected using tissue culture for virus isolation (0/22). Using PCR and agarose gel electrophoresis, we could detect HSV-1 DNA in 8/22 patients. Using a biotinylated-probe internal to the predicted sequence of the PCR product, HSV-1 DNA was detected in 10/22 patients by ELISA. We conclude that HSV-1 DNA is shed into the oral cavity of patients presenting with sub-clinical RHL and that the PCR-ELISA technique represents a more sensitive method to monitor HSV-1 shedding than conventional tissue culturing or PCR-electrophoresis alone.

Adult↗