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Biomedical subjects

W Richards

Publications and source records attributed to W Richards.

At least 19 recordsLinked to original sources

Managing change.

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Dental Care↗

Reasons for tooth extraction in four general dental practices in South Wales.

Tooth retention has been one of the main aims of oral care which in turn could have contributed to the social oral health divide. To investigate this issue further, data collected for a group audit was used to study the reasons for tooth extraction for patients attending for routine treatment at four dental practices. The practices served populations in areas with different levels of deprivation in South Wales. In 558 teeth extracted over 417 visits, the reasons for extractions were: caries 59%, periodontal disease 29.1%, pre-prosthetic 1%, wisdom teeth 4.6%, orthodontic 5.5%, trauma 1.2%, patient request 2.4% and 6.2% other reason. The number of extraction visits per day within the group of dental surgeons varied with three practitioners performing more than three extraction visits per day while one practitioner had only 0.51. These reasons did not significantly depend on levels of deprivation. However, significantly more teeth were extracted for caries in the most deprived group in comparison to the least deprived. Therefore, could there be a case for appropriate extractions in the quest for equitable care?

Adolescent↗

Oral health care.

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Dental Care↗

Effect of posaconazole on cytochrome P450 enzymes: a randomized, open-label, two-way crossover study.

Posaconazole is an antifungal with a wide-spectrum of activity against common and emerging fungal pathogens. In this randomised, open-label, two-way crossover study, the potential for drug interactions with posaconazole via the cytochrome P450 (CYP450) enzyme pathway was evaluated. Thirteen subjects received posaconazole tablets (2 x 100 mg) once daily for 10 days or no treatment; following a 14-day washout period, subjects were crossed over to the alternate treatment. The inhibition spectra of posaconazole were examined using a cocktail of the following probe substrates: caffeine (CYP1A2), tolbutamide (CYP2C8/9), dextromethorphan (CYP2D6 and total CYP3A4), chlorzoxazone (CYP2E1), and midazolam (hepatic CYP3A4). Except for midazolam, which was intravenously infused on Day 10, the cocktail probes were administered simultaneously on Day 9 during both treatment periods. Blood and urine samples were collected at specified times to quantitate probe substrates and/or metabolites. Based on insignificant differences in mean probe ratios, posaconazole did not inhibit CYP1A2, 2C8/9, 2D6, or 2E1. However, the midazolam AUC((tf)) was higher in the posaconazole than no-treatment group (93.4 n gh/ml versus 51.4 ng h/ml, P<0.01), indicating inhibition of hepatic CYP3A4. Drug interactions mediated by various CYP450 are common with the currently available triazole antifungals, however these results suggest that posaconazole may have an improved and more narrow drug interaction profile (CYP3A4 only) compared with other triazoles.

Adult↗

Comparison of patient satisfaction after redo and primary fundoplications.

BACKGROUND: Although much has been written about the results and patient satisfaction with fundoplication for the treatment of gastroesophageal reflux disease, the reports have focused primarily on surgical successes. With the growing number of fundoplications being performed, more patients are requiring reoperation because of recurrent symptoms or side effects. Reports of success rates for reoperation are available, but information regarding patient satisfaction is limited. METHODS: All the patients undergoing fundoplication at our institution were sent short-form health surveys (SF-12), Gastroesophageal reflux disease-specific quality-of-life questionnaires (QOLRAD), and queries regarding long-term satisfaction. RESULTS: Between November 1992 and July 2000, 221 patients (198 primary and 23 redo) underwent fundoplication. There were 19 open cases (3 primary and 16 redo). In the primary group, 173 patients underwent Nissen, 23 underwent Toupet, and 2 underwent Collis fundoplications. In the redo group, 12 patients underwent Nissen, 9 underwent Toupet, 1 underwent Collis, and l underwent Belsey fundoplications. Follow-up surveys were completed for 130 patients (112 primary and 18 redo) at a mean of 32.6 months (range, 0.8-98 months). In the primary group, 87% of the patients were satisfied with their operation, as compared with 75% in the redo group. There was a trend toward higher SF-12 mental scores (46 +/- 12 vs 40 +/- 14; p = 0.07) and QOLRAD scores (6.2 +/- 1.3 vs 5.2 +/- 2.0; p = 0.07) in the primary fundoplication group. There was a significant difference in the SF-12 physical scores between the groups (32 +/- 13 for the primary group vs 18.5 +/- 11 for the redo group; p = 0.0002). Additionally, 61% of the patients in the redo group were again using antireflux medications, whereas only 24% of the patients in the primary group were using medications again. CONCLUSION: Gastroesophageal reflux disease symptom scores and quality-of-life scores for patients undergoing redo fundoplication are lower than the scores of patients having primary fundoplication. Quality of life is similar between primary and redo fundoplication patients in the mental component. However, redo patients do not do as well physically more than 2 years after surgery.

Fundoplication↗

The impact of attendance patterns on oral health in a general dental practice.

OBJECTIVE: The aim of this study was to examine the impact of attendance patterns on oral health in the context of government policy on dental care and registration in the UK. METHOD: The data involved 643 consecutive patient responses to a questionnaire on dental health taken from a survey that was conducted during 1998 in an urban area of Swansea. The survey continued for a period of six months and covered patients of 18 years of age and over, responding to a questionnaire on the subjective oral health status indicators including the pattern of their attendance to dental practices. RESULTS: Regular dental care attendance has a significant positive impact on dental health while its impact on the number of teeth present is insignificant. Regular attendees also suffer significantly less from the severity, prevalence, social and psychological impacts of dental health problems. CONCLUSION: Regular dental attendance is associated with better oral health when regularity of care is defined as a visit within a two-year period. The rationality of a 15 month registration period is therefore debatable in the context of developing equitable services.

Adolescent↗

A simple nonlinear model of electrical activity in the intestine.

We have simulated electrical activity of the intestine in a computer model that describes the coupled layers of longitudinal muscle (LM) and interstitial cells of Cajal (ICC). The model suggests that pacemaker activity is due to the ICC layer, while the pulse propagation involves the LM layer that is in the excitatory state. The model describes well the experimentally observed phenomena: frequency change along the intestine, synchronization along short distances and desynchronization for long distances, and the decrease of propagation distance and propagation time along the intestine. We have observed the occurrence of phase interruptions or breaks, which are responsible for the limited values of propagation distance and time.

Biological Clocks↗

Prolonged morbidity due to delays in the diagnosis and treatment of obstructive sleep apnea in children.

The inclusion of a query concerning the presence of snoring in a questionnaires used by the Allergy Service of Childrens Hospital Los Angeles (CHLA) uncovered a significant number of patients who were experiencing prolonged and discomforting symptoms owing to previously undiagnosed obstructive sleep apnea (OSA) caused by adenotonsillar hypertrophy. Of 352 patients who were discharged with a diagnosis of OSA and tonsillectomy and/or adenoidectomy at CHLA in 1996-1997, a retrospective study of the first 45 randomly selected patients who agreed to participate in a telephone interview was performed. Analysis revealed that all patients experienced severe and discomforting symptoms with all describing severe or moderate snoring. Other symptoms included chronic mouth breathing (84%), frequent otitis media (64%), sinusitis (56%), sore throat (51%), choking (47%), and daytime drowsiness (42%). Other symptoms included poor school performance, enuresis, poor appetite and/or weight gain, dysphagia, and vomiting. Symptoms began at a mean age of approximately 2 years ("birth"-9 years), and the mean period of time between the development of significant symptoms and OSA was 3.3 years (6 months-13 years). Delay between onset of significant symptoms and surgery was > 1 year in 82% of the patients, > 2 years in 51% of the patients, > 4 years in 31% of the patients, and > 6 years in 13% of the patients. Forty percent of patients were self-referred to an otolaryngologist for treatment despite their primary care physician being aware of the symptoms. These results indicate that patient with OSA experienced prolonged morbidity and delays in treatment, which is probably widespread. Physician, parent, and third-party factors were found to have contributed to the delays in treatment.

Adenoids↗

Pathologic prognostic factors in Barrett's associated adenocarcinoma: a follow-up study of 96 patients.

BACKGROUND: The objective of this study was to evaluate a variety of histologic features, some of which to our knowledge have never been evaluated in Barrett's-associated adenocarcinoma (BAd) (such as Crohn's-like lymphoid reaction and peritumoral lymphoid response) in patients with and without preoperative neoadjuvant chemotherapy combined with radiotherapy (chemrad) to determine their prognostic significance in these two groups of patients. METHODS: Tumor sections from 96 patients (83 males and 13 females; mean age, 62 years) with resected BAd (61 with chemrad and 35 without chemrad) were evaluated for numerous histologic features such as pathologic stage according to the American Joint Committee on Cancer TNM staging system, peritumoral lymphoid infiltrate, Crohn's-like lymphoid reaction, and degree of post chemrad residual tumor and correlated with the preoperative chemrad status and with survival (mean follow-up, 23 months). RESULTS: By univariate analysis, older patient age (P = 0.02), higher pathologic stage (P = 0.02) (including depth of invasion and lymph node status), infiltrative growth pattern (P = 0.05), perineural invasion (P = 0.05), vascular invasion (P = 0.04), and the absence of a peritumoral lymphoid infiltrate (P = 0.04) were associated with shortened survival in the entire cohort and in patients without chemrad, with the exception of infiltrative growth pattern (P = 0.1 in the nonchemrad group only). Higher stage was the only feature associated with decreased survival in the chemrad group. Subcategorization of lymph nodes according to the number involved with metastases (fewer than four, four to seven, and greater than seven) had no further effect on prognosis. However, subcategorization of T1 tumors into Tla and T1b did influence prognosis in a negative manner. Using multivariate analysis, only older patient age (P = 0.005) and the absence of a peritumoral lymphoid infiltrate (P = 0.05) were statistically associated with poor survival independent of stage. In addition, perineural invasion (P = 0.07) showed a trend toward shortened survival in patients with this feature. Preoperative chemrad had no effect on survival in this retrospective nonrandomized cohort of patients. CONCLUSIONS: This study confirms the strong prognostic usefulness of the TNM staging system in patients with resected BAd, even in those patients who received preoperative chemrad. In addition, older patient age, the absence of a peritumoral lymphoid infiltrate, and possibly perineural invasion correlate with poor survival independent of pathologic stage in patients with these tumors.

Adenocarcinoma↗

Expression of the focal adhesion protein paxillin in lung cancer and its relation to cell motility.

Lung cancer can lead to abnormalities of the actin cytoskeleton structure which may be important in transformation. In this study, we have investigated the expression of the cytoskeletal associated protein paxillin in lung cancer. Paxillin is a 68 kDa focal adhesion protein, with four tandem LIM domains at the C-terminus, involved in growth factor receptor, integrin and oncogenic signaling such as v-src, BCR/ABL, and E6 of the papilloma virus. In non-small cell lung cancer (NSCLC) cell lines, paxillin localized to the focal adhesions. The possible role of paxillin in lung cancer cells was assessed by overexpressing green fluorescence protein (GFP)-paxillin construct in two separate NSCLC cell lines (Calu-1 and H661). Over the course of 48 h, GFP-paxillin consistently caused the cells to become round and to decrease cell motility as compared to normal controls, GFP-N-terminus paxillin, or GFP-LIM transfected cells. Because some lung cancers may be quite aggressive and metastasize quickly, which may be related to the cytoskeleton, we determined the expression of paxillin in NSCLC and small cell lung cancer (SCLC) cell lines and patient tumor tissues. Expression of paxillin in NSCLC and SCLC cell lines were determined by Northern blot and Western blot analysis. The expression of paxillin was consistently low in SCLC cell lines, whereas there was paxillin expression in NSCLC cell lines. There was a variability of expression of paxillin in NSCLC tumor tissue as compared to normal lung tissue. In contrast, by immunohistochemistry, we show that there was no detectable expression of paxillin in 5/5 SCLC patients. This data suggests that absence or low level of paxillin protein expression may cause certain lung cancers, such as SCLC, to be more motile and possibly more aggressive.

3T3 Cells↗

Pathologic prognostic factors in esophageal squamous cell carcinoma: a follow-up study of 74 patients with or without preoperative chemoradiation therapy.

One of the primary goals of pathologic examination of esophageal squamous cell carcinoma resection specimens is to provide information regarding morphologic features which can help prognosticate and guide management of affected patients. The purpose of this study was to determine the prognostic utility of a variety of histopathologic prognostic factors in patients with esophageal squamous cell carcinoma with and without preoperative chemotherapy and radiotherapy (chemrad). Multiple clinical and histologic features such as peri-tumoral lymphocytic infiltrate, Crohn's-like lymphoid reaction, degree of residual tumor, mitosis per 1000 cells, tumor differentiation, lymphatic/vascular invasion, perineural invasion, desmoplastic reaction, and tumor growth pattern were evaluated in patients with (53) and without (21) preoperative chemrad and correlated with survival (mean follow-up, 25 mo). Data were analyzed for the entire cohort and for each separate treatment group by univariate and multivariate analysis. Patients who received chemrad showed no significant survival benefit (hazard ratio = 2.5, P = .10). In the whole cohort of patients, higher pathologic stage (P = .04), poor tumor differentiation (P = .003), increased mitotic count (P = .005), perineural invasion (P = .01), lymphatic/vascular invasion (P = .002), tumor size (P = .05), and absence of a Crohn's-like lymphoid reaction (P = .05) were significantly associated with poor survival by univariate analysis. In multivariate analysis, poor tumor differentiation (P = .005), high mitotic count (P = .01), and vascular invasion (P = .03) were important prognostic features, independent of pathologic stage, for the entire cohort. In the chemrad group only, tumor size (in patients with macroscopic residual tumor) (P = .05), lymph node metastasis (P = .03), mitotic count (P = .01), and lymphatic/vascular invasion (P = .02) were significant prognostic indicators by univariate analysis. Upon multivariate analysis, only lymphatic/vascular invasion (P = .02) and mitotic rate (P = .01) were independent predictors of survival. In the nonchemrad group, only tumor differentiation was significant by both univariate (P = .008) and multivariate analysis (P = .03). The differences in pathologic prognostic factors between chemrad and nonchemrad treated cases suggests that chemrad has a significant effect on the biologic properties of these tumors.

Adult↗

Mapping the mental space of rectangles.

The cognitive structure of a shape space--the space of rectangles--is explored by a nonmetric scaling technique. Our experiment was designed to extract the major transformational paths or 'modes' that characterize the mental shape space. Earlier studies of rectangle similarities using multidimensional scaling have provided conflicting evidence about whether the coordinate system of the mental rectangle space is based on height and width or on area and shape (i.e. aspect ratio). Our study reveals shape to be the single dominant factor. We suspected that earlier evidence for a height-width parameterization might have been due to the presentation of rectangles upright in a pseudo-gravitational coordinate system (whereas our rectangles are randomly rotated). In a control experiment with upright (vertical or horizontal) rectangles, the heavy bias towards shape preservation was still the dominant mode. In addition, however, a secondary bias towards change of height or width emerged, exactly following the pattern expected from the biasing change in context. This finding established a concrete path by which context and frame can influence the way shape is represented. The relevance of these findings to the cognitive organization of more complex shape spaces is discussed.

Cognition↗