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Biomedical subjects

Peter Clarke

Publications and source records attributed to Peter Clarke.

8 recordsLinked to original sources
PubMed2006

Assessment of the formant frequencies in normal and laryngectomized individuals using linear predictive coding.

The objective of this study was to assess the difference in voice quality as defined by acoustical analysis using sustained vowel in laryngectomized patients in comparison with normal volunteers. This was designed as a retrospective single center cohort study. An adult tertiary referral unit formed the setting of this study. Fifty patients (40 males) who underwent total laryngectomy and 31 normal volunteers (18 male) participated. Group comparisons with the first three formant frequencies (F1, F2, and F3) using linear predictive coding (LPC) (Laryngograph Ltd, London, UK) was performed. The existence of any significant difference of F1, F2, and F3 between the two groups using the sustained vowel /i/ and the effects of other factors namely, tumor stage (T), chemoradiotherapy, pharyngectomy, cricothyroid myotomy, closure of pharyngoesophageal segment, and postoperative complication were analyzed. Formant frequencies F1, F2, and F3 were significantly different in male laryngectomees compared to controls: F1 (P<0.001, Mann-Whitney U test), F2 (P<0.001, Student's t test), and F3 (P=0.008, Student's t test). There was no significant difference between females in both groups for all three formant frequencies. Chemoradiotherapy and postoperative complications (pharyngocutaneous fistula) caused a significantly lower formant F1 in men, but showed little effect in F2 and F3. Laryngectomized males produced significantly higher formant frequencies, F1, F2, and F3, compared to normal volunteers, and this is consistent with literature. Chemoradiotherapy and postoperative complications significantly influenced the formant scores in the laryngectomee population. This study shows that robust and reliable data could be obtained using electroglottography and LPC in normal volunteers and laryngectomees using a sustained vowel.

Female↗
PubMed2006

Prospective cohort study of central venous catheters among internal medicine ward patients.

BACKGROUND: Central venous catheter (CVC) use is less well described for patients outside the intensive care unit. We evaluated CVCs and the associated bloodstream infection rate among patients admitted to the general medical service. METHODS: We performed a prospective cohort study of patients who had a CVC on admission or inserted during their stay on the general medical service in a public teaching hospital, November 15, 2004, to March 31, 2005. RESULTS: We identified 106 CVCs, 52 were present on admission and 54 were inserted; there were 682 catheter-days. The primary bloodstream infection rate was 4.4 per 1000 catheter-days (95% CI: 0.9-13): highest for catheters inserted in the emergency department compared with those inserted on other units (24 vs 1.7 per 1000 catheter-days), P = .045. By multivariable analysis, inadequate dressings were more likely among patients with a body mass index > or =30 kg/m(2), adjusted odds ratio, 3.4 (95% CI: 1.4-8.0). CONCLUSIONS: Many CVCs had previously been inserted in the emergency department or intensive care unit; therefore, strategies to reduce bloodstream infections that focus on ward insertion practices may not dramatically reduce bloodstream infection rates. Intervention strategies should target improved dressing care and consideration of early removal or replacement of catheters inserted in the emergency department.

Adult↗
PubMed2006

Adenoid cystic carcinoma of the trachea: a long-term problem.

Adenoid cystic carcinoma of the trachea, although rare, is the second most common primary tumour of the trachea. It is a slow-growing tumour found in younger patients than the more common squamous cell carcinoma and is relatively resistant to treatment, but metastasizes late in the course of disease and even in unresectable cases can be palliated successfully for many years. We present a retrospective 20-year series of this condition from a single institute encompassing 13 patients of whom 6 were resected and 7 treated by palliative methods. A review of hospital records was carried out over the period 1984-2003. Details collected included symptoms before diagnosis, length of time from onset of the first symptom to diagnosis, resection details, survival statistics and accessory procedures tried before and after consideration of resection. The overall 5-year survival was 38.5%, but the mean survival in resected patients was 66 months as against 36 months for unresectable patients. Although most patients presented with dyspnoea, this was initially often attributed to other factors. The mean time of diagnosis from the onset of symptoms was 16 months. Although complete resection remains the management of choice if feasible, modern techniques of maintaining the airway in unresectable patients can give useful palliation for years.

Adult↗
PubMed2005

Reducing variability and choosing ideal subjects for experimental gingivitis studies.

INTRODUCTION: This study was undertaken to test the hypothesis that male, non-smokers, aged 25-50 years, with a proven track record of developing gingivitis would provide suitable subjects for experimental gingivitis studies because the inter-subject variation would be greatly reduced. MATERIALS AND METHODS: Subjects were required to be men aged between 25 and 50 years, in good general health with at least four sound teeth in one posterior quadrant of the mandible. Subjects who were smokers, taking antibiotics, anti-inflammatory drugs or had any other medical, surgical or social condition making participation in the study inadvisable, were excluded. Subjects had previously participated in a 21-day experimental gingivitis study. Subjects with the most gingivitis at the end of the previous study were invited to participate first, moving down the list until the required number of subjects had been achieved. Subjects were randomly assigned to one of three toothpastes: Crest Gum Care, Mentadent P or a placebo (UK Signal). Subjects were asked to brush their teeth twice daily for 1 min., with the tooth-shield in place and containing 1 ml of their assigned toothpaste. RESULTS: Thirty-five subjects completed the study using the placebo, 36 used Mentadent P and 39 completed the study using Crest Gum Care. Both toothpastes containing active gum health ingredients (Triclosan and Zinc Citrate in Mentadent P and Stannous Fluoride in Crest Gum Care) resulted in statistically significant reductions in gingival bleeding and inflammation. Although a directional reduction, there was no statistically significant reduction in plaque scores. No significant differences between the two active groups were established. CONCLUSION: The factors that were controlled or measured and analyzed in these studies were: gender, smoking status, age and chronic gingivitis level. The results add support to the hypothesis that male subjects show less variation, however there is limited evidence linking the female menstrual cycles to variations in gingivitis status. Further research in this area is required before definitive conclusions can be made. Selecting a subject population in order to decrease variation must be undertaken with caution. A subject population selected for particular attributes can be extremely valuable when assessing the anti-gingivitis potential of new agents, but this population would be as biased if used for large efficacy clinical trials. The data obtained will not necessarily be able to be generalized, that is, applicable to the whole population. However there is sufficient evidence to justify balancing for (or excluding) smokers from subject populations in experimental gingivitis studies.

Adult↗
PubMed2005

Information seeking and compliance in planning for critical care: community-based health outreach to seniors about advance directives.

This field experiment in 3 states investigated factors that encourage seniors to explore critical-care choices and to complete an advance directive when approached through a community-based outreach. The intervention featured a detailed, home-based guide and subsequent telephone counseling. Seniors were contacted through established community organizations such as church or service groups, residential centers, and retirement associations. Results disclosed the importance of cognitive variables (participants' sense of a future vulnerable self and efficacy of advance planning for care) in explaining which seniors requested a guide. Compliance in completing a directive, however, depended solely on different patterns of reading the guide and talking about critical care. Neither information seeking nor completing a directive correlated with participants' actual health status.

Advance Care Planning↗
PubMed2003

Utility of the lateral chest radiograph in the evaluation of patients with a positive tuberculin skin test result.

STUDY OBJECTIVES: In the United States, chest radiographs are performed on patients with positive tuberculin skin test (TST) results. It is not known whether, in addition to a single posteroanterior radiograph, a lateral chest radiograph is clinically indicated or cost-effective. We sought to determine the utility of the lateral chest radiograph in evaluating TST-positive adults. DESIGN: Cross-sectional study. SETTING: Tertiary-care hospital. PATIENTS: Adults with positive TST results. MEASUREMENTS: Findings on posteroanterior radiographs alone were compared to posteroanterior and lateral chest radiographs. RESULTS: In 2 of 535 cases (0.4%), lateral chest radiographs revealed a calcified granuloma not visible on posteroanterior radiographs. This finding did not alter patient management. In all other cases, lateral radiographs only confirmed findings seen on posteroanterior chest radiographs. CONCLUSION: Treatment altering findings were always visible on posteroanterior radiographs alone. These results suggest that lateral chest radiographs are not useful in evaluating adults with positive TST results.

Adult↗