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Biomedical subjects

R G Newcombe

Publications and source records attributed to R G Newcombe.

At least 37 records · Page 2Linked to original sources
PubMed2004

Sentinel lymph node biopsy in patients with multifocal breast cancer.

BACKGROUND: Multifocal or multicentric breast cancer has been suggested as a contraindication for sentinel node biopsy (SNB). However, recent studies have demonstrated that all quadrants of the breast drain through common afferent channels to a common axillary sentinel node. This should mean that the presence of multifocal tumour should not affect the lymphatic drainage. The purpose of this study was to evaluate the feasibility and accuracy of SNB in patients with multifocal breast cancer using a peritumoural injection technique for sentinel lymph node (SN) mapping. METHODS: In the ALMANAC multicentre trial validation phase, we took SNB samples from 842 patients with node negative, invasive breast cancer with use of a blue dye and radiolabelled colloid mapping technique at the peritumoural injection site. All patients underwent standard axillary treatment after SNB. Seventy-five of the 842 patients had multifocal lesions on final histopathologic examination. The following analysis is focused on patients with multifocal lesions. RESULTS: A mean number of 2.4 SNs were identified in 71 of 75 patients (identification rate: 94.7%). Thirty-one patients had a positive SN, 40 a negative SN. Standard axillary treatment confirmed the SN to be negative in 37 of 40 patients, whereas three patients revealed positive non-sentinel lymph nodes (false-negative rate: 8.8%). Overall SN biopsy accurately predicted axillary lymph node status in 68 of 71 patients (95.8%). CONCLUSION: SNB accurately staged the axilla in multifocal breast cancer and may become an alternative to complete axillary lymph node dissection in node negative patients with multifocal breast cancer.

Aged↗
PubMed2004

Development of methods to enhance extrinsic tooth discoloration for comparison of toothpastes. 2. Two-product clinical study.

BACKGROUND: Extrinsic staining of teeth is considered to be unsightly and a number of 'whitening' toothpastes have been formulated to inhibit or remove such tooth discoloration. The aim of this study was to compare the stain prevention of two toothpastes. METHOD: The study was a single-blind, randomised, placebo-controlled, crossover design, balanced for residual effects involving 24 healthy dentate volunteers. The treatments were as follows: (1) a whitening toothpaste product, (2) an experimental toothpaste formulation and (3) water. For each 4-day rinse period, subjects were rendered stain free on the teeth and tongue. Approximately on the hour from 09:00 to 16:00 hours, subjects rinsed with chlorhexidine mouth rinse for 1 min followed by warm black tea for 1 min. The treatment interventions were at 09:00 and 16:00 hours and before the chlorhexidine rinse. The toothpastes were rinsed as 3 g/10 ml water slurries and water as a 10 ml rinse each for 2 min. On day 5, subjects were scored for tooth and tongue stain intensity and area, and the product of these was calculated. The washout period was at least 9 days. RESULTS: Treatment differences for the teeth were highly significant but not for the tongue. Paired contrasts for tooth stain intensity, area and product were mostly all significantly in favour of reduced staining by the experimental formulation compared with water and the whitening product. There were no significant differences between water and the whitening product. CONCLUSIONS: Using a forced dietary staining method, the data support a tooth stain-inhibitory/-removal action for the experimental formulation, but not the whitening product.

Adult↗
PubMed2004

Development of methods to enhance extrinsic tooth discoloration for comparison of toothpastes. 1. Studies in vitro.

BACKGROUND: The interaction of chlorhexidine with dietary chromogens to cause extrinsic dental staining has been exploited in vitro and in vivo to study tooth discoloration and its control. These studies in vitro investigated factors that might enhance stain formation, and evaluated formulations to inhibit the stain with the primary aim of devising a protocol for use in vivo. METHOD: The standard method cycled acrylic specimens through saliva, 0.2% chlorhexidine and tea on the hour 8 times per day and stain was measured using a spectrophotometer. Test interventions were 3 "whitening" toothpastes (A, P, R), a fluoride toothpaste (C) and water. In studies 1 and 3 interventions were at 09:00 and 16:00, and in studies 2 and 4 at 09:00 and 13:00. Between cycles, specimens remained dry in studies 1 and 2 and were maintained in water day and night in studies 3 and 4. Studies 5-7 determined the influence of tea temperature, exposure time and concentration, and chlorhexidine temperature and exposure time on stain development. Studies 8-10 modified the standard procedure using tea at triple strength and 50 degrees C, and assessed stain inhibition by toothpastes and water using optical density, colorimetric and visual assessment recordings. RESULTS: In studies 1-4, there were highly significant differences between interventions. Overall, the experimental whitening paste (P) produced the most stain inhibition, and water or the proprietary whitening paste (R), produced the least stain inhibition. More stain inhibition was seen with interventions at 09:00 and 16:00. Both tea concentration and temperature significantly influenced staining. Chlorhexidine temperature did not influence staining. Exposure time to tea and chlorhexidine had a small effect on staining. In studies 8 and 9, interventions at 09:00 and 16:00 were more effective; the most stain inhibition was with paste P and the least with water, paste R being intermediate. In study 10, P was the most effective and R the least effective interventions. CONCLUSIONS: These studies in vitro suggest that the chlorhexidine tea stain model can be manipulated to enhance stain and thereby should improve discrimination between stain inhibition formulations. The timing of interventions in the model appears to be important. These studies in vitro were used to plan a clinical protocol.

Acrylic Resins↗
PubMed2004

Clinically practical blood volume assessment with fluorescein-labeled HES.

BACKGROUND: Standard techniques for measuring blood volume (BV) entail administering radioactivity and human albumin. This is laborious, expensive, and impractical in acute settings. An alternative method suitable for widespread routine application was assessed. STUDY DESIGN AND METHODS: Seventy-nine ambulant outpatients and 18 intensive care unit (ICU) patients were prospectively recruited. Measurements of RBC volume (RCV) and plasma volume (PV) were performed with radiochromium-labeled RBCs (51Cr), radioiodinated albumin (125I), and fluorescein-labeled HES (FITC-HES). Small molecules overestimate PV because of vascular endothelial dysfunction (ED) and increased capillary permeability; a reference value for PV was therefore derived with the RCV and Hct. RESULTS: Mean PV with 125I dilution was 230 mL (SD, 185 mL) greater than that with FITC-HES in outpatients. This difference was more exaggerated, 345 mL (SD, 371 mL), in ICU patients likely to have ED. Both the PV measured with FITC-HES and the 125I dilution correlated closely with the PV derived with RCV and Hct (r = 0.950 and 0.925, respectively) in the ICU patients. CONCLUSION: FITC-HES estimates PV more accurately than 125I. FITC-HES should replace radioactive tracers for assessing BV. Comparing the estimates of PV with molecules of differing molecular weights may have clinical utility as an indicator of ED.

Albumins↗
PubMed2004

Dentine hypersensitivity: a randomised, double-blind placebo-controlled study of the efficacy of a fluoride-sensitive teeth mouthrinse.

OBJECTIVES: Potassium and fluoride salts have been used in the treatment of dentine hypersensitivity (DH). The primary aim of this study was to compare a fluoride-containing mouthrinse product with a placebo rinse for the treatment of DH. A secondary aim was to compare effects on plaque index (PI) and gingivitis index (GI). MATERIAL AND METHODS: The study was a double-blind, randomised, two-treatment parallel design involving 91 subjects with DH. At screening, an air evaporative stimulus (AES) was used for selection. Approximately 4 weeks later, at the baseline visit, DH was recorded, using a response-based visual analogue scale (VAS) from upper and lower incisors, canines, premolars and first molars in response to AES and from two to six teeth in response to a cold water stimulus (CWS). PI and GI were also recorded. Subjects were then allocated the test or placebo rinse. On days 28 and 56, VAS scores were again recorded for AES and CWS, with PI and GI recorded at day 56. RESULTS: Both groups improved symptoms to day 28 and again to day 56. The majority of the data favoured the test rinse as more effective but there was no clear evidence for a statistically significant difference between test and placebo. PI at lingual sites approached significance for the test rinse. CONCLUSIONS: The placebo response has again been shown to play a significant role in DH clinical trials and narrows the range over which to detect treatment differences. Study designs to minimise or prevent the placebo response in DH seem worthy of consideration.

Adolescent↗
PubMed2004

Clinical development and evolution in plaque removal performance of a battery powered toothbrush.

BACKGROUND AND AIM: There is growing evidence that the new generation of electric toothbrushes are more effective than manual toothbrushes. The primary aim of these studies was to compare, as an indication of the stage of development, the plaque removal properties of a prototype battery powered toothbrush with an established product. A secondary aim was to utilise the data to appraise plaque accumulation together with the patterns of removal. METHOD: The three studies presented used the same, single-examiner, randomised, single-blind cross-over design involving up to 24 healthy volunteers. The prototype brushes, E6500 versions s1, s2 and s3 and E8000 with head speeds of 6500 and 8000 oscillations/min were compared with a similar design marketed product (MP) with a head speed of 8800 oscillations/min. All brushes had circular brush heads with oscillating rotating actions. Subjects accumulated plaque over a 4-day period during which no oral hygiene measures were performed. On day 4, the plaque accumulation was scored by index. Subjects then used the allocated toothbrush for 2 min. This was followed by a re-scoring of the remaining plaque. RESULTS: Studies 1 and 2 showed significantly less plaque removed by prototype E6500 (s1) and prototype E6500 (s2), respectively, than by MP. In study 3, prototype E8000 removed similar quantities of plaque to MP (approximately 65%). In contrast prototype E6500 (s3) only removed 60% of accrued plaque. Differences, however, did not reach statistical significance. CONCLUSIONS: The study methodology was appropriate to distinguish between the study toothbrushes and was furthermore able to establish a level of comparability for one of the prototype modifications with a similar MP.

Adult↗
PubMed2004

Effectiveness of rugby headgear in preventing soft tissue injuries to the head: a case-control and video cohort study.

OBJECTIVE: To determine if headgear use by rugby players was associated with a reduced risk of head or facial laceration, abrasion, or fracture. METHODS: An emergency department based case-control study in South Wales, UK, with cases being rugby players treated for superficial head and facial injuries and controls being their matched opponents during the game. A review of videos of the 41 games in the 1999 Rugby World Cup was also carried out to compare with the case-control study. Odds ratios (OR) and 95% confidence intervals (95% CI) were used to measure association between exposure (headgear wearing) and outcome (head and facial injuries). RESULTS: In the case-control study, 164 pairs were analysed, with headgear worn by 12.8% of cases and 21.3% of controls. Headgear use was associated with substantial but non-significant reductions in superficial head (OR = 0.43, 95% CI 0.13 to 1.19) and facial (OR = 0.57, 95% CI 0.21 to 1.46) injuries. The video study followed 547 players over 41 games, during which there were 47 bleeding injuries to the head. Headgear use significantly reduced the risk of bleeding head injury in forwards (OR = 0.14, 95% CI 0.01 to 0.99, p = 0.02), but not in backs. There was also a higher risk of facial injury among forwards, but this was not significant. CONCLUSIONS: The combined results suggest that headgear can prevent certain types of superficial head injuries in players at all levels of the game, but the evidence is strongest for superficial head injury in elite forwards. A randomised controlled trial would be the best way to study this further.

Case-Control Studies↗
PubMed2004

Are T1 weighted images helpful in MRI of cervical radiculopathy?

MRI in patients with cervical myelopathy or radiculopathy usually includes T(1) weighted (T(1)W) and T(2) weighted (T(2)W) images. We prospectively examined a hypothesis that T(2)W alone is sufficient to diagnose the cause of cervical myelopathy and radiculopathy and that the T(1)W sagittal images do not provide additional useful information. 30 patients presenting with a history of cervical radiculopathy with or without myelopathy were prospectively assessed by MRI. Those with a history suggestive of intrinsic primary cord disease or who had previously had surgery were excluded. Two neuroradiologists, blinded to the clinical information, separately viewed the sagittal and axial T(2)W images alone, and at a later time, the full set of T(1)W and T(2)W images. Image quality, location and severity of disease and confidence of diagnosis at each level were scored on 4- or 5-point scales. The T(1) sequences did not demonstrate any significant lesions not already seen on the T(2)W images alone. The T(1)W sequence may safely be omitted in patients with radiculopathy.

Adult↗
PubMed2003

Preoperative assessment of prognostic factors in rectal cancer using high-resolution magnetic resonance imaging.

BACKGROUND: The aim was to determine the accuracy of preoperative magnetic resonance imaging (MRI) in the evaluation of pathological prognostic factors that influence local recurrence and survival in rectal cancer. METHODS: Ninety-eight patients undergoing total mesorectal excision for biopsy-proven rectal cancer were assessed prospectively using high-resolution MRI for tumour (T) and nodal (N) staging using the tumour node metastasis classification, depth of extramural tumour spread, the presence or absence of extramural venous invasion, a threatened circumferential resection margin and serosal involvement at or above the peritoneal reflection. Preoperative magnetic resonance assessment of these prognostic factors was compared with histopathological findings in carefully matched whole-mount sections of the resection specimen. RESULTS: There was 94 per cent weighted agreement (weighted kappa = 0.67) between MRI and pathology assessment of T stage. Agreement between MRI and histological assessment of nodal status was 85 per cent (kappa = 0.68). Although involvement of small veins by tumour was not discernible using MRI, large (calibre greater than 3 mm) extramural venous invasion was identified correctly in 15 of 18 patients (kappa = 0.64). MRI predicted circumferential resection margin involvement with 92 per cent agreement (kappa = 0.81). Seven of nine patients with peritoneal perforation by tumour (stage T4) were identified correctly using MRI. CONCLUSION: High-resolution MRI of the rectum allows preoperative identification of important surgical and pathological prognostic risk factors. This may allow both better selection and assessment of patients undergoing preoperative therapy.

Adult↗
PubMed2003

Development of low erosive carbonated fruit drinks. 1. Evaluation of two experimental orange drinks in vitro and in situ.

OBJECTIVES: To determine the in vitro erosive potential and in situ erosive effect of two new formulation low calorie carbonated orange drinks with that of two conventional diet products and water. METHODS: In the in vitro study, six specimens of deciduous and permanent enamel were randomly allocated to each of the five products and a '4h' protocol employed. In the in situ study, 15 healthy volunteers participated in a single centre, single blind, 5-phase crossover study, conducted according to Good Clinical Practice, and employing a validated model. RESULTS: The in vitro erosive potential of the experimental formulations was less than that of the comparators at all time points. Conversely, the observed erosive potential of both experimental formulations was greater than that of the control. Consistent statistically significant differences were found in relation to permanent enamel only. Unfortunately, the in situ study did not produce results entirely consistent with those of the in vitro study. Notably, a generally progressive loss of enamel was observed in specimens exposed to the control. CONCLUSIONS: The data from the in vitro study show the experimental formulations to have low comparative erosivity. However, the methodologies in vitro and in situ somewhat unusually do not correlate in ranking the erosivity of drinks. The results of this study should therefore be viewed with caution, further research being clearly warranted.

Adolescent↗
PubMed2003

Investigation of erosion and abrasion on enamel and dentine: a model in situ using toothpastes of different abrasivity.

BACKGROUND: Studies in vitro suggest that abrasion and erosion may act synergistically to produce wear of enamel and dentine. Methods in situ are recently available to study separately erosion and abrasion of dental tissues. The aim of this study was to combine two in situ protocols to study the interplay between erosion and abrasion of enamel and dentine. METHOD: The study was a single-blind, randomised, five-treatment cross-over design involving 15 healthy volunteers. During each 10-day study period, subjects wore from 0900 to 1700 h an upper removable acrylic appliance holding one polished enamel and one polished dentine specimen. The specimen treatment regimens were: 1. Drinking water and brushing with toothpaste A. 2. Drinking water and brushing with toothpaste B. 3. Drinking orange juice. 4. Drinking orange juice and brushing with toothpaste A. 5. Drinking orange juice and brushing with toothpaste B. Drinking and brushing times were around 0900, 1100, 1300 and 1500 h. Drinks were consumed as 250 ml over 10 min and brushing ex vivo for 1 min to each specimen. Measurement of tissue loss was made on days 5 and 10 of each period using a profilometer. RESULTS: All treatments produced increasing tissue loss over time, which was considerably greater for dentine than enamel. For enamel, the data at days 5 and 10 showed a significant effect for erosion (i.e. orange juice was significantly more erosive than water), but no significant effect for abrasion (i.e. no significant difference between the two toothpaste treatments). The combined orange juice and toothpaste effects were directional for synergy but did not reach significance. For dentine at day 10, many specimens exceeded the 50 microm set limit of the profilometer and only day 5 data were considered. There were significant effects for erosion (orange juice produced significantly more erosion than water) and for abrasion (paste A was significantly more abrasive to dentine than paste B). The synergy effect could not be examined for dentine due to the truncation effect as the set limit of the profilometer was exceeded. CONCLUSIONS: Erosion increases the susceptibility of enamel to toothpaste abrasion. Dentine is considerably more susceptible than enamel to erosion and abrasion alone or combined. Dentine loss appears to correlate with toothpaste abrasivity (RDA value).

Adolescent↗
PubMed2003

A comparison of the effect of advice to eat either '5-a-day' fruit and vegetables or folic acid-fortified foods on plasma folate and homocysteine.

OBJECTIVE: To assess and compare the effects of natural folate (100 micro g) with those of folic acid from fortified sources (100 micro g/day) on plasma folate and homocysteine. DESIGN: Randomized controlled trial (parallel groups). SETTING: Men and women living in South Wales, UK. SUBJECTS: A total of 135 healthy individuals recruited from the local workforce and blood donor sessions. All subjects possessed the 'wild-type' CC genotype for C677T polymorphism in methylenetetrahydrofolate reductase (MTHFR). INTERVENTIONS: Subjects underwent one of the following dietary interventions for 4 months: (1) fortified diet-usual diet plus 100 microg/day folic acid from fortified foods; (2) natural folate diet-usual diet plus 100 microg/day folate from natural sources; (3) control-usual diet. RESULTS: The fortified group increased reported intake of folic acid from fortified foods compared to other groups (P<0.001) achieving an extra 98 microg/day (95% CI 88-108). The natural folate group increased reported intake of natural source folates compared with the other two groups (P<0.001), but achieved a mean increase of only 50 microg/day (95% CI 34-66). Plasma folate increased (P<0.01) by a similar amount in both intervention groups compared to controls (fortified group 2.97, 95% CI 0.8-5.1; natural group 2.76, 95% CI 0.6-4.9. Plasma homocysteine, vitamins B(6) and B(12) were not significantly changed. CONCLUSIONS: Subjects achieved increases in folate intake using fortified foods more easily than by folate-rich foods, however both sources increased plasma folate by a similar amount. These levels of intake were insufficient to reduce homocysteine concentrations in MTHFR CC homozygotes, but may be more effective in other genotypes.

Adolescent↗
PubMed2003

Reduction in plasma total homocysteine through increasing folate intake in healthy individuals is not associated with changes in measures of antioxidant activity or oxidant damage.

BACKGROUND: Various mechanisms have been proposed to explain the association between plasma total homocysteine (tHcy) and risk of cardiovascular disease, including oxidative activity of homocysteine. OBJECTIVE: To explore the putative role of reactive oxygen species in the association between plasma tHcy and risk of cardiovascular disease in healthy individuals. DESIGN: A double-blind, placebo-controlled crossover intervention to increase folate intake through diet (increased consumption of folate-rich foods) and supplement (400 micro g folic acid) was carried out in 126 healthy men and women. Measurements were made of antioxidant activity in red blood cells and plasma, and products of oxidant damage in plasma. RESULTS: Diet and supplement-based interventions led to an increase in measures of folate status and a reduction in plasma tHcy. This was not associated with any significant change in measures of antioxidant activity (plasma and red blood cell glutathione peroxidase activity and red blood cell superoxide dismutase activity) or oxidant damage (plasma malondialdehyde), although an improvement in plasma total antioxidant capacity just failed to reach significance. CONCLUSIONS: In healthy individuals lowering plasma tHcy does not have any functional implications regarding oxidative damage.

Adult↗
PubMed2003

Use of videotape to assess mobility in a controlled randomized crossover trial of physiotherapy in chronic multiple sclerosis.

OBJECTIVES: To determine to what degree assessment of mobility based on comparison of videotape recordings before and after courses of physiotherapy in patients with chronic multiple sclerosis (MS) is reliable, correlates with 'live' assessments and indicates benefit. DESIGN: Prospective data collection within a randomized crossover controlled trial of physiotherapy at home, as an outpatient, or 'no therapy' in 40 patients. SETTING: Hospital outpatients: outpatient and home physiotherapy. OUTCOMES: Mobility change based on a comparison of short video recordings before and after each treatment period was scored independently by two physiotherapists blinded to therapy type and other measures of outcome. Scores were compared with changes in the Rivermead Mobility Index (RMI) and other indices assessed by a physiotherapist in the patient's home. RESULTS: The two video observers agreed substantially on patient outcome. Changes in walking based on video correlated with RMI for home treatment (r = 0.41, p = 0.008) but not for hospital or no treatment periods (r = 0.14 and 0.15): video changes correlated with the 'live' assessor's global change score inconsistently ('no therapy' r = 0.48, p = 0.002, hospital r = 0.30, p = 0.06 and home r = 0.17, p = 0.30 treatment periods). Based on video data alone, improved mobility was evident following home therapy for only one observer but not for the other or the averaged scores of both. CONCLUSION: There was substantial agreement between two observers deciding on change in mobility based on independent blinded evaluation of short video sequences. However the correlations of these with 'live' assessments were variable. Physiotherapy had a less clear benefit on mobility based on video analysis alone compared with 'live' assessments. The study highlights the need for more objective measures of habitual mobility over longer periods.

Adult↗
PubMed2002

The implementation of guidelines and computerised forms improves the completeness of cancer pathology reporting. The CROPS project: a randomised controlled trial in pathology.

The aim of this study was to determine whether reporting guidelines and computerised form-based reports improve the completeness of histopathological cancer data available for patient management and population cancer registration and to evaluate the acceptability of the intervention. The study was a randomised controlled trial with a split unit design and stratified cluster randomisation. All 16 hospital pathology laboratories in Wales were randomly allocated to report either breast or colorectal resection specimens by computerised form or conventional free text. 1044 reports were analysed in the study arm, 998 in the control arm. Use of pre-defined forms led to a 28.4% (95% confidence interval (CI): 15.7-41.2%) increase in complete reporting of a minimum dataset required for cancer registration and a 24.5% (95% CI: 11.0-38.0%) increase in complete reporting of minimum data required for patient management. Form-based reporting was acceptable to pathologists and preferred by clinicians. In conclusion, guidelines and computerised forms significantly improve the quality of histopathology reporting.

Breast Neoplasms↗
PubMed2002

Developing a quality scoring system for epidemiological surveys of genetic disorders.

A prototype database of published articles containing data on the frequency of human inherited disorders has been developed for use in clinical contexts, in medical research, for epidemiological studies, and in the planning of genetic services. It can be accessed at http://www.uwcm.ac.uk/uwcm/mg/fidd/. The information available in the literature comes from a wide range of publications, not all can be described primarily as epidemiological surveys. A preliminary assessment indicated that the quality of published articles was highly variable. Very few published articles describe quality-scoring systems for epidemiological surveys in general. We have developed a new scoring system to assess the quality of published articles on genetic disease frequency based on five main criteria and nine component scores. We carried out a first pilot study, to test its feasibility, usefulness and reproducibility. Eleven assessors scored six papers on the epidemiology of Huntington disease. As a result of these findings, we modified the scoring system to define each component more clearly. This was then evaluated in a second pilot study, which utilized six assessors to score 20 papers. The consensus between assessors remained relatively poor. We feel that while it may be possible to improve the scoring system further, the degree of improvement attainable may be limited by the poor standards of content and presentation of published surveys, which led to confusion and uncertainty by assessors. This pilot exercise has shown the need to raise the awareness of researchers and clinicians about the basic quality standards to be required of epidemiological genetic surveys.

Epidemiologic Research Design↗