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Biomedical subjects

R Newcombe

Publications and source records attributed to R Newcombe.

At least 37 records · Page 2Linked to original sources
PubMed1995

The comparative effects on plaque regrowth of phenolic chlorhexidine and anti-adhesive mouthrinses.

The inhibition of bacterial attachment to the tooth surface is one possible approach to plaque control. This study evaluated in vivo the plaque inhibitory action of a novel copolymer reported to have considerable antiadhesive properties in vitro. The study was a single blind, 5-treatment, randomised Latin square crossover design, incorporating balance for carry-over effects. The rinses were the antiadhesive (1%), the antiadhesive with 0.02% chlorhexidine, a 0.2% chlorhexidine rinse product, an essential oil/phenolic rinse product and water. 15 volunteers participated and on day 1 of each study period were rendered plaque-free, ceased toothcleaning and rinsed 2 x daily, under supervision, with the allocated formulation. On day 5, plaque was scored by index and area. Washout periods were 2 1/2 days. Alone or combined with chlorhexidine, the antiadhesive agent showed no effects greater than water. The chlorhexidine rinse was significantly more effective than the essential oil/phenolic rinse which in turn was significantly more effective than the other rinses.

Anti-Infective Agents, Local↗
PubMed1995

Radiological assessment of constipation.

A scoring system for faecal loading was constructed by two experienced observers using the abdominal radiographs of 20 children. Four other observers independently graded the radiographs using this system and there was a high degree of agreement between all six observers (p < 0.001), suggesting that radiological assessment of constipation can be standardised.

Adolescent↗
PubMed1994

The normalization of recreational drug use amongst young people in north-west England.

An anonymous self-report survey of drug use among a cohort of 776 14-15 year olds in North-West England was conducted at the end of 1991, aiming to estimate prevalence and profile users. Six in 10 reported being offered drugs, and 36 per cent to using drugs (20 per cent in the past month). Over half of those offered drugs had tried them. Lifetime prevalence was highest for cannabis (32 per cent), with five other drugs each being used by 10-14 per cent. Three groups identified were cannabis smokers, solvents sniffers, and stimulant/psychedelic (or dance drug) users. The population parameters of drug use were estimated at 33-40 per cent, suggesting up to 200,000 local young adults have used drugs. Most significantly, the proportion of young women being offered and using drugs and the prevalence of drug trying amongst young people in 'middle-class' schools, suggests a substantial social transformation is underway in respect of recreational drug use. The results of this survey confirm a general trend apparent in other British studies. As this cohort is tracked into the mid 1990s, the sociological implications will be significant.

Adolescent↗
PubMed1993

A 6-month home usage trial of a 1% chlorhexidine toothpaste (1). Effects on plaque, gingivitis, calculus and toothstaining.

Research and development has been aimed towards the development of toothpastes for oral hygiene and gingival health benefits. The most effective antiplaque agent to date, chlorhexidine, is difficult to formulate into active toothpaste products. Despite some encouraging findings for experimental chlorhexidine toothpastes, there are to date no commercially available products. Based on positive findings from an experimental gingivitis study, this investigation evaluated 2 chlorhexidine toothpastes, one with fluoride, as adjuncts to oral hygiene. The study was a double-blind controlled, parallel, balanced group design, extending over 6 months. A total of 297 volunteers commenced the study after screening for a minimum acceptance level of gingivitis. At baseline, 6, 12 and 24 weeks, stain, gingival, bleeding and plaque indices were recorded, together with a calculus index at 6, 12 and 24 weeks. After a baseline prophylaxis, volunteers used the allocated product 2 x per day, with no other oral hygiene instructions given. Plaque, gingival and bleeding scores improved in all 3 groups, but to an overall significantly greater extent in the active groups. However, staining and calculus indices were significantly increased in the active compared to the control group. If the local side-effects of chlorhexidine are considered to be acceptable, these chlorhexidine toothpastes could be recommended for the same clinical applications as other chlorhexidine products. The apparent compatibility of fluoride with chlorhexidine in the one product may be pertinent to caries prevention.

Adolescent↗
PubMed1993

Evaluation of a mouthrinse containing chlorhexidine and fluoride as an adjunct to oral hygiene.

Chlorhexidine and fluoride have valuable preventive roles in dental and oral diseases. There is also evidence that in caries prevention, together, they provide additive benefits. However, combined chlorhexidine/fluoride formulations have rarely been evaluated. The aim of this study was to determine whether a 0.12% chlorhexidine, 100 ppm F- mouthrinse provided adjunctive oral hygiene benefits compared to a minus active control rinse. The study was a randomised double-blind parallel design involving 102 subjects of whom 99 completed the 6 week experimental period. Subjects rinsed 2x per day for 1 min with 15 ml of the allocated rinse. Normal toothbrushing procedures were maintained throughout the study. At 6 weeks, plaque and gingivitis scores were significantly lower and the incremental reduction significantly larger in the active rinse group. However, as expected, toothstaining was significantly increased with the active rinse. It is apparent that this chlorhexidine/fluoride rinse could be used in those regimens recommended for other chlorhexidine formulations. The value of the formulation in caries prevention would seem worthy of further investigation.

Adolescent↗
PubMed1993

The effects of a chlorhexidine toothpaste on the development of plaque, gingivitis and tooth staining.

Chlorhexidine has found many uses in clinical dentistry as an antiplaque agent. To date, effective chlorhexidine-containing toothpastes have not been made available. This study was the first phase in the evaluation of a 1% chlorhexidine toothpaste, formulated to ensure a high availability of the contained antiseptic. The study was a 19-day, randomised double-blind placebo-controlled, crossover experiment al gingivitis clinical trial employing 14 healthy human volunteers. From a zero plaque and low gingivitis baseline, the development of plaque, gingivitis and dental staining was measured on days 12 and 19 of the 2 study periods. The toothpaste was used 2x a day as a slurry rinse with no other form of oral hygiene. The washout period was 21 days. The development of plaque and gingivitis was statistically and clinically highly significantly reduced during the use of the active compared to the placebo product. Conversely, dental staining was statistically and clinically significantly increased. The product deserves further evaluation for potential clinical use.

Adult↗
PubMed1993

The natural history of congenital myotonic dystrophy: mortality and long term clinical aspects.

Although the genetic basis of the congenital form of myotonic dystrophy has recently been clarified, data as to outcome in terms of life expectancy and morbidity are scanty. Life table data based on a cohort of 115 patients with a confirmed diagnosis of congenital myotonic dystrophy are presented. The data suggest a 25% chance of death before 18 months of age and a 50% chance of survival into the mid-30s. The profile of disease and complications among survivors is also charted.

Adolescent↗
PubMed1992

Glucocorticoids exacerbate kainic acid-induced extracellular accumulation of excitatory amino acids in the rat hippocampus.

Glucocorticoids (GCs) compromise the ability of hippocampal neurons to survive various insults, and do so, at least in part, by exacerbating steps in the glutamate/N-methyl-D-aspartate (NMDA)/calcium cascade of damage. As evidence, GCs impair uptake of glutamate by hippocampal astrocytes, the GC endangerment of the hippocampus is NMDA receptor dependent, and GCs exacerbate kainic acid (KA)-induced calcium mobilization. These observations predict that GCs should also exacerbate KA-induced accumulation of extracellular glutamate and aspartate. To test this, adrenalectomized rats were given replacement GCs in either the low or high physiological range. Three days later, rats were anesthetized and 1 mM KA was infused through a dialysis probe placed in the dorsal hippocampus. Extracellular amino acid concentrations in the dialysate were then assessed by HPLC. After KA infusion, high-GC rats (30 +/- 3 micrograms/dl) had significantly elevated concentrations of glutamate and aspartate compared with low-GC rats (all less than 0.95 micrograms/dl). The glutamate accumulation was due to GCs raising pre-KA concentrations, whereas the aspartate accumulation was due to GCs exacerbating the KA-induced rise. Glutamine concentrations were unaffected by KA, whereas the high-GC regimen elevated glutamine concentrations both before and after KA. Taurine concentrations rose after infusion of KA, but were unaffected by GC regime, whereas alanine concentrations were unaffected by either manipulation. Serine concentrations were unaffected by KA, but were depressed both before and after KA in high-GC rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1992

The effects of antimicrobial acrylic strips on the subgingival microflora in chronic periodontitis.

This study investigated the effects of root planing and/or the placement of acrylic strips containing chlorhexidine, metronidazole or tetracycline on the composition and antimicrobial susceptibility of the subgingival flora in chronic periodontitis. 101 periodontal pockets from 73 patients were entered into 6 treatment groups which were, chlorhexidine, metronidazole or tetracycline strips, root planing, root planing followed by metronidazole strips and a control, no treatment group. Total anaerobic counts and anaerobe/aerobe ratios were estimated from samples taken before treatment and 1, 2, 4, 8 and 12 weeks after treatment. In addition, a more detailed analysis of the effects of the treatments on the subgingival flora was carried out on 12 pockets in 12 patients. Tetracycline strips, metronidazole strips and root planing and metronidazole strips were more effective than chlorhexidine strips in causing reductions in total anaerobic count and anaerobe/aerobe ratio. However, the changes in microbial parameters rebounded to approach baseline levels 4 weeks after treatment. Chlorhexidine caused no detectable changes in the composition of the subgingival microflora, while metronidazole had a variable effect. Tetracycline appeared to effect major shifts in the composition of the microflora of treated pockets but caused a marked selection of tetracycline-resistant organisms.

Acrylic Resins↗
PubMed1991

Thyrotropin response to thyrotropin-releasing hormone in elderly patients with and without acute illness.

The response of thyrotropin (TSH) to thyrotropin-releasing hormone (TRH) was measured in 70 clinically euthyroid elderly patients who were acutely ill and in 70 age- and sex-matched euthyroid controls who were free of acute disease. The incremental TSH response (delta TSH) was often blunted (less than 2 mU/l) in both groups, though more often in those with acute illness (30%) than in those without (19%). However, in patients from both groups who had a blunted delta TSH, there was often a substantial proportional rise in TSH. A substantial proportional TSH rise may be useful in differentiating between genuine thyroid disease and euthyroid sick syndrome in elderly patients with a blunted delta TSH.

Acute Disease↗
PubMed1991

The effect of some chlorhexidine-containing mouthrinses on salivary bacterial counts.

A number of chlorhexidine mouthwashes are available commercially which differ in formulation and regimen of use. As a comparative measure of antimicrobial persistence, this study evaluated the effect of 4 chlorhexidine mouthwash formulations on salivary bacterial counts after a single rinse. The study was a randomised single-examiner blind 5-way crossover investigation employing a panel of 10 young healthy human volunteers. The 0.12% and 0.2% commercial formulations when rinsed according to the respective manufacturers instructions produced similar large and prolonged reductions in salivary bacterial counts during the 7-h period. A 0.1% formulation also commercially available produced minimal effects on salivary bacterial counts and was little different to the saline rinse. A reformulated 0.1% rinse, not commercially available at the time of the study, produced significant salivary bacterial count reductions over the 7-h period albeit to a lesser degree of magnitude than to the 0.2% and 0.12% rinses. The results were consistent with comparative plaque inhibitory studies of the formulations and suggest that the method is a quick and simple way of screening products for antimicrobial and antiplaque potential.

Adult↗
PubMed1991

Triclosan and sodium lauryl sulphate mouthwashes (I). Effects on salivary bacterial counts.

A number of commonly used toothpaste ingredients, such as detergents, possess not inconsiderable antimicrobial activity. Additionally, specific ingredients including triclosan are now added to toothpastes to enhance such activity and to improve plaque inhibition. To date, there have been few studies of the antimicrobial properties in vivo of individual toothpaste ingredients. Most investigations have evaluated the whole toothpaste product. Persistence of antimicrobial action in vivo has been shown to relate to potential plaque inhibitory action. The aim of this study was to compare the magnitude and duration of salivary bacterial count reductions produced by a single rinse of 0.2% triclosan, 1% sodium lauryl sulphate (SLS) and 0.2% chlorhexidine mouthwashes. 16 volunteers took part in a single-blind latin-square randomised crossover designed study with balanced residual effects. Before and for time periods up to 420 min following rinsing with the allocated mouthwashes, saliva samples were obtained and processed for total anaerobic counts. With the exception of the saline control rinse, the 3 test solutions produced considerable reductions in bacterial counts which remained significant to 3 h for triclosan and 7 h for SLS and chlorhexidine. However, at most time periods after baseline, the effects of chlorhexidine were significantly greater than triclosan and SLS. Overall, SLS had significantly greater effects than triclosan. Incremental values from 30 min post rinsing were always positive for SLS and triclosan, indicating bacterial recovery, whereas these values were negative for chlorhexidine. The results indicate that triclosan and SLS provide some persistence of antimicrobial activity in the oral cavity when used at relatively high dose compared to a toothpaste vehicle.

Adult↗
PubMed1990

Seasonal variation and the results of the dexamethasone suppression test.

There is controversy over the presence of a circannual rhythm in cortisol values in samples provided by depressed patients after a standard dexamethasone suppression test (DST). Post-DST cortisol values from patients admitted to an acute psychiatric ward over a 2-year period have therefore been analysed by appropriate statistical tests. No evidence was found for significant seasonal variation.

Depressive Disorder↗
PubMed1990

The use of antimicrobial acrylic strips in the nonsurgical management of chronic periodontitis.

Evidence to date has demonstrated the potential value of acrylic strips to deliver antimicrobial compounds into periodontal pockets. The present study was designed to evaluate further the therapeutic effect of antimicrobial acrylic strips in the management of chronic periodontitis. A total of 101 pockets in 69 patients were randomly treated with (1) chlorhexidine strips, (2) metronidazole strips, (3) tetracycline strips, (4) root planing, and (5) combined root planing and metronidazole strips. Immediately before and after treatment clinical measurements of disease were recorded over a three-month period. For all treatment groups significant improvements in clinical parameters were seen compared to control untreated sites but the most effective treatment was combined root planing and metronidazole and the least effective chlorhexidine. Although not significant, combined root planing and metronidazole also appeared to produce some adjunctive effects on clinical parameters compared to root planing alone. Antimicrobial acrylic strips appear useful treatments for chronic periodontitis, but should be used primarily as an adjunct to conventional root planing.

Acrylic Resins↗
PubMed1990

Reporting cervical intra-epithelial neoplasia (CIN): intra- and interpathologist variation and factors associated with disagreement.

Eight histopathologists, based at different hospitals, who had previously examined 100 consecutive colposcopic cervical biopsies were circulated with the results of the initial study. The slides were then 'reblinded' and re-examined by the pathologists who, as before, assigned them into one of six diagnostic categories. The degree of interpathologist agreement for the seven observers who returned usable responses was characterized by kappa statistics and compared to the corresponding figures for the same observers from the previous study. Although some of the observers showed significant alterations in their diagnostic practices there was persistent poor agreement for CIN 1 and 2, mediocre agreement for CIN 3 and excellent agreement for invasive carcinoma. Intra-observer agreement was consistently better than inter-observer agreement for each of the diagnostic categories. Significant differences were found among observers in the degree of intra-observer variability. The 20 cases in which there was most disagreement were re-examined by one of the authors who compared these with 20 biopsies which caused little disagreement. Disagreement was considered to be associated with florid papilloma-virus changes, basal cell hyperplasia and severe inflammation in varying combinations. On the basis of these findings we suggest changes in the terminology of CIN lesions.

Carcinoma in Situ↗
PubMed1990

The effect of triclosan, stannous fluoride and chlorhexidine products on: (I) Plaque regrowth over a 4-day period.

A number of substances have been incorporated into toothpastes or gels to inhibit plaque regrowth. The aim of this study was to evaluate triclosan and stannous fluoride products for plaque inhibitory properties by comparison with a chlorhexidine or saline rinse and a control product which was a conventional commercially available toothpaste. In a blind 8 cell cross-over study, 15 volunteers rinsed 2 x a day for 4 days with slurries of the products or the saline and chlorhexidine solutions. No other form of oral hygiene was performed and plaque regrowth from a zero baseline was recorded by plaque score and plaque area. Plaque regrowth was significantly less with the chlorhexidine rinse and significantly greater with the saline rinse compared to the toothpaste and gel products. No significant differences were found between the test and control products. The results again demonstrate that commercially available toothpastes have plaque inhibitory effects which so far appear difficult to improve upon by the addition of specific ingredients, in this case stannous fluoride or triclosan. Commercially available products of known activity would appear useful benchmarks for comparison of experimental formulations.

Adult↗
PubMed1990

The effect of triclosan, stannous fluoride and chlorhexidine products on: (II) Salivary bacterial counts.

A previous study demonstrated that triclosan and stannous fluoride containing oral hygiene products reduced plaque regrowth compared to saline but were not more effective than a conventional commercial fluoride/anionic detergent toothpaste. To further understand these results, this study measured the persistance of antimicrobial activity of the same products by recording the duration of salivary bacterial count reductions following a single exposure to each product. Comparison was also made with a chlorhexidine rinse as the positive control. From a panel of 16 volunteers, in an 8-cell randomised cross-over designed study, salivary bacterial counts were recorded at baseline and to 420 min. All test and control products were significantly more effective than saline and significantly less effective than chlorhexidine at suppressing bacterial counts. Unlike chlorhexidine, evidence of bacterial recovery was apparent after the 30-min sampling time. There were essentially no significant differences between the test and control products, although the stannous fluoride toothpaste performed marginally better than other products. The findings are consistent with the plaque regrowth results previously obtained and again demonstrate to date that it is difficult to surpass the antimicrobial and plaque inhibitory properties of conventional commercially available toothpastes by the addition of antimicrobial agents such as triclosan and metal salts.

Adult↗