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Biomedical subjects

W J Duncan

Publications and source records attributed to W J Duncan.

At least 19 recordsLinked to original sources
PubMed2005

Diagnosis of fetal ductus arteriosus aneurysm: importance of the three-vessel view.

OBJECTIVE: To present four cases of ductus arteriosus aneurysm (DAA) detected by fetal echocardiography and highlight the value of the three-vessel view in the diagnosis of DAA. METHODS: In addition to the standard fetal echocardiographic views, we examined the three-vessel view in four cases of DAA. The three-vessel view was achieved by sliding the transducer cranially from the four-chamber plane toward the fetal upper mediastinum to demonstrate cross-sections of the main pulmonary artery, the ascending aorta and superior vena cava arranged in a straight line from the left anterior to the right posterior aspect of the mediastinum. DAA was diagnosed when there was a tortuous ductus arteriosus with a dilation that protruded leftward of the aortic arch. CASE SERIES: In the first case, an insulin-dependent diabetic woman underwent fetal ultrasound examination at 36 weeks' gestation showing right-to-left cardiac disproportion and bidirectional flow in the aorta and main pulmonary artery (PA). The three-vessel view showed a dilated ductus arteriosus (DA) which was stenosed at its distal end. In the second case, a woman had fetal ultrasound scans at 38 and 39 weeks' gestation for suspected intrauterine growth restriction and oligohydramnios. The scans identified an abnormal aortic arch and the three-vessel view showed an elongated vascular structure at the distal end of the PA, which was the DAA. In the third case, a woman with a high-risk obstetric history had multiple scans showing an abnormal PA to aorta relationship, with an apparent 'kink' in the PA. The three-vessel view clarified that this was the DAA. In the fourth case, a woman was scanned because of a 3-kg weight gain in 1 week. The fetal ultrasound scan showed moderate polyhydramnios with normal fetal growth and normal intracardiac anatomy and flow, and the three-vessel view demonstrated a large DA. In each of these cases, the DAA appeared to have occurred in isolation with non-specific clinical findings. CONCLUSION: We advocate the use of the three-vessel view, in conjunction with the standard echocardiography views currently employed, to assist in the diagnosis of DAA.

Adult↗
PubMed2005

Health departments' implementation of public health's core functions: an assessment of health impacts.

OBJECTIVES: The purpose of this article was to investigate the relationship between state health agencies' adherence to the recommendations of the United State's Institute of Medicine's (IOM) report, "The Future of Public Health", and changes in their populations' health. STUDY DESIGN: Data were abstracted from agencies' plans, budgets, annual reports, etc. spanning a 5-year period. A comprehensive change in population health measure over the same period was drawn from the UnitedHealth Group's annual survey. METHODS: Configurations, based on public health core functions, were established using linear regression and qualitative comparative analysis. The dependent variable was a holistic measure of change in a state population's health status. RESULTS: State agencies that most completely adopted a public health model emphasizing assessment, assurance and policy development also experienced significant improvements in their population health measures. CONCLUSIONS: State agencies that more completely adopted the IOM's public health core functions had a concomitant improvement in their populations' health statuses. Further research to explore if there is a causal link between adoption of the core functions and positive health impacts is warranted.

Government Agencies↗
PubMed2003

Ovine periodontitis as a potential model for periodontal studies. Cross-sectional analysis of clinical, microbiological, and serum immunological parameters.

OBJECTIVES: : To investigate infection and host immunity patterns in sheep with naturally occurring "broken-mouth" periodontitis. MATERIALS AND METHODS: : Eight periodontally healthy (HS) and eight periodontally diseased ewes (PDS) were selected. Subgingival plaque and sera were collected and examined for evidence of human periodontitis-associated pathogens. Serum IgG titers were measured by ELISA to multiple strains of Porphyromonas gingivalis, Bacteroides forsythus, Dichelobacter nodosus, Actinobacillus actinomycetemcomitans, Prevotella intermedia, and Fusobacterium nucleatum as well as several purified antigens (cysteine proteases, LPS, K, and fimbriae). RESULTS: : Neither the organism Aa nor antigens to Aa were found in any animal. Most animals were positive for Pg, Bf, and Pi, but DNA probes detected no difference between HS and PDS relative to amounts of pathogens in subgingival plaque. PDS had significantly higher serum IgG titers to all Pg strains, to 50% of Bf strains, to the Pi and Fn strains, and to fimbriae and the two cysteine proteases (p-values ranging from 0.05 to 0.001). Regression analysis demonstrated a significant association between number of teeth lost and serum IgG antibody titers to whole-cell sonicate antigens of P. gingivalis strains (p<0.01) and body weight (p<0.01). CONCLUSIONS: : The presence of pathogens associated with periodontitis was reflected in differences in serum IgG titers between healthy and diseased sheep. This may have influenced animal body weight and might have systemic health and economic consequences. The data suggest that susceptible and non-susceptible sheep can be identified for periodontal research.

Aggregatibacter actinomycetemcomitans↗
PubMed2002

Relative effectiveness of powered and manual toothbrushes in elderly patients with implant-supported mandibular overdentures.

AIM: The aim of this study was to compare the clinical effectiveness of a powered toothbrush (Braun Oral-B Plaque Remover 3-D) and a manual soft toothbrush (Oral-B Squish-grip brush) for the control of supragingival plaque and soft tissue inflammation around implants supporting mandibular overdentures. MATERIAL AND METHODS: The study sample involved 40 edentulous subjects, aged 55-80 years, having 2 unsplinted mandibular implants supporting a complete removable overdenture opposed by a maxillary complete denture. In this single-blinded, randomised, cross-over clinical trial, two 6-week experimental phases were separated by a 2-week wash-out period. 2 weeks prior to each experimental phase (pre-entry visits), implant abutments were polished to remove all plaque and a standardised instruction in the use of the toothbrush was given. Modified plaque and bleeding indices were recorded at the start and end of each experimental period. Mean index scores at each phase were analysed using paired t-test, and the mean number of sites showing a change in plaque or mucositis were compared using the Mann-Whitney U-test. Combined data from 2 different implant systems were considered after controlling for implant type. RESULTS: Only minor changes in plaque and bleeding scores were observed following the two test periods. There were no statistically significant differences between the manual and powered toothbrushes. CONCLUSION: Manual and powered brushes were found to be of comparable efficacy with regard to improvement in peri-implant bleeding and plaque indices.

Aged↗
PubMed2001

A national network for the tele-education of Canadian residents in pediatric cardiology.

A trial of 11 video-conferenced teaching sessions for residents in pediatric cardiology was performed by the 7 training programs in Canada in order to share expertise in specialized areas, to expose trainees to educational telemedicine, and to acquaint residents with other programs and personnel. Topics included cardiac pathology, arrhythmias, magnetic resonance imaging, fetal physiology, pulmonary hypertension, and cardiomyopathy. The sessions were evaluated by 93 residents by questionnaire for content and technology. Session content was highly rated. Videoconference picture quality was highly rated, but sound quality and visual aids were rated as neutral or unsatisfactory by a significant minority, related to problems with several early sessions, subsequently corrected. 60% of respondents rated the videoconferences as good as live presentations. Presenters were generally satisfied although they required some adjustments to videoconferencing. The average cost per session was $700 Canadian. Videoconferencing of resident educational sessions was generally well accepted by most presenters and residents, and the trial has formed the basis for a national network. Adequate organizational time, and careful attention to audiovisual needs, are most important. Videoconference guidelines are suggested for presenters based on this experience.

Canada↗
PubMed1998

Cerebral blood flow velocities monitored by transcranial Doppler during cardiac catheterizations in children.

Transcranial Doppler (TCD) was used to evaluate brain circulation during cardiac catheterizations in 32 children requiring pulmonary (n=10) or aortic balloon dilatations (n=2), ductus arteriosus coil insertions (n=5), or angiography (n=15). Cerebral blood flow velocity (CBFV) in the middle cerebral artery was measured before (baseline), during, and after each procedure (mean+/-95%ci). High-intensity transient signals (HITS) were also detected during these maneuvers. Balloon angioplasty decreased CBFV by 63+/-11% from baseline (P < 0.01). Shorter durations of the inflation cycle resulted in earlier CBFV recovery (r=0.78). During angiography, CBFV increased by 11+/-4% (P < 0.01) in all except one case that showed retrograde diastolic flow. Mean total HITS count was 44 (95%ci.limits: 27,74). These signals were more frequently found in septal defects or systemic arterial manipulations. Pediatric cardiac catheterization may impose transient fluctuations in brain perfusion as indicated by TCD, but their clinical implications are uncertain. CBFV changes during balloon angioplasty emphasize the importance of rapid inflation/deflation cycles. TCD can monitor such changes and evaluate preventive measures.

Adolescent↗
PubMed1998

Preparing for the future in a local public health organization.

One of the most difficult issues in strategic planning in public health organizations is how to harness the energy generated in the process of strategic thinking and focus it on strategy formulation. This article is about one local public health organization's experience in developing program priorities, building consensus about the priorities, and making operational the adaptive strategies relative to each program. The results should be useful to all public health organizations attempting to direct strategic thinking toward the formulation of practical and motivational strategies for the future.

Alabama↗
PubMed1997

The Hemopump as a left ventricular assist device in pediatric applications: initial Canadian applications.

Three children aged 11 months, and eight and nine years were supported with a Hemopump as a potentially life saving measure for circulatory failure. Left ventricular assist time ranged from 10 to 32 h. None of the three patients could be successfully weaned from the device because of complications of bleeding, arrhythmia or neurological insult. Despite poor outcomes, each patient demonstrated important hemodynamic stabilization with the device. The Hemopump is suggested as a potentially life saving treatment modality for selected pediatric patients who have critical left ventricular failure.

Canada↗
PubMed1997

Realignment of periodontally affected maxillary teeth--a periodontist's perspective. Part 1: Treatment rationale and methodology.

Orthodontic therapy is indicated for adults when periodontitis has resulted in drifting or tilting of upper anterior teeth. Periodontal disease must be controlled before, during, and after orthodontic treatment. Simple cases may be treated using removable appliances and light, intermittent forces, but complex cases with an underlying skeletal disharmony should be referred to an orthodontist. Permanent retention is usually required after orthodontic treatment in adults.

Adolescent↗
PubMed1997

Systolic function of the univentricular heart: comparison of the Simpson's rule with acoustic quantification.

BACKGROUND: Acoustic quantification (AQ) is a new method of obtaining real-time information about systolic ventricular function. This method establishes a ;blood-tissue interface' and computes an intraventricular blood volume in real time to derive a beat to beat instantaneous ejection fraction. AQ assessment of systolic function has been reported previously in patients with normal cardiotypes and varying degrees of myocardial dysfunction. OBJECTIVE: To determine the potential utility of AQ in patients with abnormal ventricular morphology, in whom systolic function may be difficult to measure by traditional methods. PATIENTS AND DESIGN: Seventeen children (nine females) ranging in age from five days to 18 years (mean 6.9 years) with univentricular left ventricle heart morphology underwent a prospective and comparative echocardiographic study of ventricular function with the use of AQ and manual planimetry (single plane Simpson's rule). Imaging was done during steady state without sedation. Routine scan planes were performed, followed by repeat scanning of the univentricle from the apical four-chamber view in the AQ mode. Subsequently, manual planimetry using Simpson's rule was performed from an online graphical analysis package to measure systolic and diastolic frames from the conventional replay images. These data were used to calculate ejection fraction using standards previously established. The results were then compared with real-time AQ results. SETTING: Tertiary care referral center. RESULTS: Scan time for the combined standard and AQ imaging averaged 45 mins (range 35 to 65 mins). Measured ejection fraction by AQ and manual planimetry were 44 +/- 11% and 46 +/- 10%, respectively. Statistical analysis by repeated measures ANOVA with Bonferroni/Dunn correction (F = 0.6, df = 1,32, P = 0.44) demonstrated significant agreement between AQ and manual planimetry with an intraclass correlation coefficient of 0.93. Bland-Altman analysis was used to provide a graphic display of the clinical significance of differences in the comparison of the two methods of measurement. CONCLUSIONS: These findings support the use of AQ for continuous online determination of indexes of systolic function for patients with univentricular left ventricle morphology. The variability in the morphology inherently present within this group of patients results in a wider variability of determined ejection fraction. Particular attention must be directed to the technical aspects of image acquisition and AQ application to ensure accuracy.

Adolescent↗
PubMed1997

Realignment of periodontally-affected maxillary teeth--a periodontist's perspective. Part II: Case reports.

Orthodontic therapy as part of a patient's overall periodontal rehabilitation may have many benefits. For the three patients described in this report, these benefits included: an improvement in appearance, which indirectly also increases the patient's motivation; improved access for cleaning teeth; restitution of edge-to-edge incisal occlusion; an improvement in lip-seal, thereby reducing anterior gingival dryness; reduction in the non-axial loading which can act as a cofactor with plaque to accelerate periodontal destruction; and possible regeneration of lost attachment apparatus through the combination of surgery and orthodontic tooth-intrusion. Successful orthodontic treatment in these patients depended upon adequate control of periodontal inflammation by thorough scaling and the maintenance of good oral hygiene. Treatment may be carried out in patients suffering from refractory periodontitis, provided inflammation is controlled during the period of orthodontic tooth movement; however, close monitoring is needed, especially if the patient continues to smoke.

Adult↗
PubMed1994

Transcatheter stent implantation for recurrent pulmonary venous pathway obstruction after the Mustard procedure.

A 5 year old boy presented with obstruction of the pulmonary venous pathway four years after the Mustard procedure. A successful balloon dilatation of the pulmonary venous pathway was performed but the benefit was transient. Placement of a 10 mm balloon expandable intravascular stent across the recurrent stenosis resulted in complete relief of the obstruction with prompt resolution of the clinical signs. The delivery system was modified to facilitate stent delivery.

Catheterization↗
PubMed1994

General and functional level health care managers: neither 'manage' very much.

This paper reports the results of a study of 40 (20 paired general and functional level managers) in 20 health care organizations. The managers were personally interviewed and were asked to supply additional self-coded data from calendar entries, telephone logs, and in/out baskets. The results of this study indicated that health care managers, like their business counterparts, spend most of their time performing tasks other than traditionally defined management functions. In fact, major portions of the typical day of general and functional managers are spent exchanging routine information, processing paperwork, and interacting with others. As the studies have confirmed with regard to business managers, the health care general managers in this study focused much of their attention on issues and events external to the organization. The information sources they valued most were primarily external to the organization. The functional managers, by comparison, were more oriented to internal issues and information sources. In general, this study indicated that the patterns of managerial work in health care organizations are similar to those in business organizations and that managers in both settings spend half their time doing things that are not 'managerial' in nature.

Data Collection↗
PubMed1993

Transcatheter management of pulmonary venous pathway obstruction with atrial baffle leak following Mustard and Senning repair.

Two patients presenting with pulmonary venous baffle obstruction following Mustard or Senning repair of transposition of the great arteries were successfully treated with percutaneous balloon dilatation. At the time of baffle dilatation, a significant systemic to pulmonary venous Mustard baffle leak was successfully closed with a Rashkind ductal occluder device. Specific features pertaining to the morphology of the baffle defect that allowed successful catheter occlusion are discussed and compared to that found in a Senning patient. The important adjunctive role of transoesophageal echocardiography within the catheterization laboratory is emphasized.

Cardiac Catheterization↗
PubMed1993

Double-outlet single ventricle and an abdominal vascular mass: in utero diagnosis with pathological confirmation.

A fetal echocardiographic scan was performed when routine prenatal ultrasound screening failed to identify four cardiac chambers. The scan showed a single ventricle with an associated circoid varicosity. Because of these anomalies, amniocentesis was suggested and trisomy 18 confirmed. The presence of major cardiac structural anomaly should prompt careful and specific review of all fetal anatomy to screen for syndrome identification and consideration of amniocentesis.

Abnormalities, Multiple↗
PubMed1992

Keeping strategic thinking in strategic planning: macro-environmental analysis in a state department of public health.

This paper examined the tendency of strategic decision makers in public health to allow their strategic planning process to degenerate into short-term, operational management. The temptation is great in light of pressing current problems. However, the danger of not thinking strategically about the future and of failing to attempt to position the organization in such a way as to take advantage of its strengths and minimize the adverse consequences of its weaknesses can be catastrophic. An attempt is made to illustrate how one state department of public health attempted to ensure that strategic thinking remained a part of its strategic planning process. The process was built around the energizing of the expertise present in the department and the mobilization of resources under the direction of the State Health Officer. The process is ongoing and is constantly fine tuned. However, the procedure utilized can be adapted easily to the unique circumstances facing most public health organizations.

Decision Making↗