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Biomedical subjects

J L Keller

Publications and source records attributed to J L Keller.

At least 19 recordsLinked to original sources
PubMed2000

Prevalence and predictors of human papillomavirus infection in women in Ontario, Canada. Survey of HPV in Ontario Women (SHOW) Group.

BACKGROUND: Human papillomavirus (HPV) is thought to be the primary cause of cervical intraepithelial neoplasia and cervical cancer. We determined the age-specific prevalence of HPV infection and its risk factors in Ontario women. METHODS: We obtained 2 cervical specimens from randomly selected women (in 5-year age categories, from 15 to 49 years) who were being seen in 32 family practices for cytologic screening. The specimens were tested for carcinogenic HPV by the hybrid capture II assay (Digene Corp., Silver Spring, Md.) and by polymerase chain reaction (PCR) and genotyping. RESULTS: Of 1004 women eligible to participate, samples were obtained from 955 (95.1%). The prevalence of HPV (as determined by the hybrid capture II method) was highest, at 24.0% (95% confidence interval [CI] 16.5% to 31.5%), among women 20 to 24 years of age and was progressively lower in older age groups, reaching 3.4% (95% CI 0.1% to 6.7%) in women 45 to 49 years old. The prevalence of HPV (any type) as determined by PCR showed a similar pattern but was significantly higher (p = 0.01) among women 45 to 49 years old than among those 40 to 44 years old (13.0% [95% CI 6.4% to 19.6%] v. 3.3% [95% CI 0.1% to 6.5%]). Risk factors for positivity with the hybrid capture II method were never-married status, divorced or separated status, more than 3 lifetime partners, more than 1 partner in the preceding year, cigarette smoking and current use of oral contraceptives. The presence of squamous intraepithelial lesions on cytologic examination was strongly associated with positivity with the hybrid capture II assay (odds ratio 96.0, 95% CI 22.3 to 413.4; p < 0.01). INTERPRETATION: The highest prevalence of HPV was 24.0%, in women 20 to 24 years old. Risk factors supported a sexual mode of transmission, and there was a strong association between HPV and abnormal cervical cytologic results.

Adolescent↗
PubMed2000

Nonsusceptible Streptococcus pneumoniae in children with chronic otitis media with effusion and recurrent otitis media undergoing ventilating tube placement.

CONTEXT: Children with chronic otitis media are at risk for nonsusceptible Streptococcus pneumoniae (NSP) infection. If these children undergo ventilating tube placement, there is an opportunity to culture middle ear fluid and the nasopharynx to determine carriage of NSP. OBJECTIVE: To determine the incidence of NSP carriage, NSP antibiotic susceptibility and risk factors for NSP carriage in children with chronic otitis media undergoing tube placement. DESIGN AND SETTING: Prospective cohort study in an academic medical center with recruitment of patients from an otolaryngology private practice and clinic. PATIENTS: Children < 18 years of age undergoing tube placement for chronic otitis media. INTERVENTIONS: Myringotomy and tube placement, with culture of middle ear fluid and nasopharynx. MAIN OUTCOME MEASURES: The incidence of NSP cultured from the middle ears and nasopharynx of recruited subjects with the use of the minimum inhibitory concentration break points for penicillin susceptibility recommended by the National Committee for Clinical Laboratory Standards. RESULTS: S. pneumoniae was identified in at least 1 site from 23 of 300 study subjects (7.6%); of these 23, 12 case subjects (52.2%) harbored NSP. Of the risk factors assessed by preoperative questionnaire, only younger age was associated with NSP colonization (P < 0.0001). Of the six oral cephalosporins studied, cefpodoxime and cefuroxime showed good in vitro activity against S. pneumoniae isolates with intermediate penicillin resistance. CONCLUSIONS: Children with chronic otitis media undergoing tube placement may carry NSP and provide a means of monitoring the incidence of NSP and antibiotic susceptibilities for children with ear infections in their communities. Younger age is a risk factor for NSP carriage in this population.

Adolescent↗
PubMed1999

Pervasive developmental delay in children presenting as possible hearing loss.

OBJECTIVE/HYPOTHESIS: Children who fail to develop adequate language skills and/or appropriate social skills by age 2 years often are referred to the department of otolaryngology for otolaryngologic examination and evaluation of possible hearing deficits. Discovering a gross disparity between hearing function and language ability often uncovers an underlying developmental disorder satisfying criteria for diagnosis on the spectrum of autism and pervasive developmental delay (PDD). The otolaryngologist has a unique opportunity to identify these autistic children and initiate their evaluation and management. STUDY DESIGN: Retrospective review. METHODS: Review of charts of children referred over the past 4 years to the Department of Otolaryngology for possible hearing loss identified 15 children who were later diagnosed with PDD. RESULTS: Fifteen children initially referred for hearing evaluation were subsequently identified with a diagnosis of PDD. Males outnumbered females 4 to 1, with the average age of referral being 2 years. One third of the patients displayed middle ear disease that improved with PE tube placement. One third of the patients showed brainstem conduction dysfunction on auditory brainstem evoked response testing. CONCLUSIONS: Children with developmental delays, especially higher functioning ones, may present with a myriad of language and communication deficits that are often mistakenly attributed to hearing loss. Otolaryngologists and audiologists can assist in their early identification and appropriate referral for therapy.

Audiometry, Pure-Tone↗
PubMed1997

Management of the carotid artery following penetrating injuries of the soft palate.

Penetrating injuries of the soft palate are not uncommon in the pediatric population. The majority are minor, requiring only conservative treatment. Despite the close proximity of the carotid artery to lateral soft palate and tonsillar fossa, the incidence of carotid injury is low. When carotid injury does occur, it is usually secondary to blunt trauma to the carotid with a resultant thrombosis. A concomitant neurologic deterioration often follows occurring from 3 h to 3 days after the initial injury (Hengerer et al. (1984). Laryngoscope 94, 1571-1575). The potential neurologic sequelae of such an injury make these seemingly innocuous wounds a diagnostic and management dilemma for the clinician. We present an unusual case of an internal carotid artery pseudoaneurysm in a neurologically intact child following soft palate impalement. We review the diagnostic evaluation including angiography and magnetic resonance angiography, the surgical approach, and postoperative issues including anticoagulation. The literature is reviewed and a discussion regarding the approach to penetrating injuries of the soft palate is presented.

Aneurysm, False↗
PubMed1993

Reliability of prehospital rating scales for case severity and status change.

The purpose of this report is to determine the reliability and sensibility of the currently available prehospital rating scales by a prospective evaluation of ambulance call reports using generalizability methodology. Sequential samples of emergency call data from the Hamilton Base Hospital Paramedic program database were used to sample calls randomly for a two-phase study. Phase I and II used blinded ambulance call report forms presented to six rates during three sessions in each phase. Generalizability (reliability) coefficients were then generated to determine the degree of reliability for the scales in both phases of the study. The generalizability coefficients for all scales are substantial or excellent using the standards commonly applied to agreement statistics. The conclusion of the study is that all ambulance officers can use the prehospital scales reliably. The reliability of these general measures is one of the parameters that will allow us to evaluate where basic and advanced prehospital care have an impact on overall patient outcome.

Emergency Medical Technicians↗
PubMed1993

Effect of fire department first-responder automated defibrillation.

STUDY OBJECTIVE: To examine the effect of fire department first-responder defibrillation on time to defibrillation in a mid-sized community with two tiers of emergency medical services (EMS) ambulance response. DESIGN: Retrospective cohort. SETTING: The study area was the region of Hamilton-Wentworth, which has more than 445,000 inhabitants and covers 1,136 km2 (438 square miles). TYPE OF PARTICIPANTS: We studied 297 victims of out-of-hospital cardiac arrest presenting to the EMS system between May 1, 1990, and April 30, 1991. MEASUREMENTS AND MAIN RESULTS: The mean defibrillation interval was decreased from 11.96 minutes to 8.50 minutes (P < .001) by the introduction of fire first-responder defibrillation. Survival was significantly greater with bystander-witnessed arrest, initial rhythm of ventricular fibrillation, and presence of a pulse on arrival in the emergency department. CONCLUSION: In our EMS system, fire first-responders were able to provide defibrillation in significantly shorter times than ambulance attendants. Other EMS systems should review their response times and consider instituting first-responder defibrillation as one means of reducing defibrillation intervals.

Aged↗
PubMed1992

Effectiveness of steroid therapy in acute exacerbations of asthma: a meta-analysis.

The objective of this study was to determine the effect of steroid therapy on pulmonary function, admission rates, and relapse rates in patients presenting with acute exacerbations of asthma. Computerized MEDLINE and SCIENCE CITATION searches were combined with review of reference lists from book chapters and articles to identify published randomized trials on steroid interventions. Over 700 articles were reviewed by two independent reviewers who identified 30 relevant randomized controlled trials for analysis. Study validity was independently assessed by two reviewers and information regarding populations, interventions, and outcomes was abstracted. Binary outcomes were combined and reported as odds ratios (OR), using the Mantel-Haenszel method. Individual and pooled effect sizes (ES) were determined for pulmonary function data. The authors found that the use of steroids early in the treatment of asthmatic exacerbations reduces admissions in adults (common OR 0.47; 95% confidence interval (CI) 0.27, 0.79) and children (OR 0.06-0.42). They found steroids effective in preventing relapse in the outpatient treatment of asthmatic exacerbations (OR 0.15; CI 0.05, 0.44). Oral and intravenous steroids appear to have equivalent effects on pulmonary function in acute exacerbations (ES -0.07; CI -0.39, 0.25). The authors conclude that overall, steroid therapy provides important benefits to patients presenting to emergency departments with acute exacerbations of asthma. Further research into dosage, alternative routes of administration, and alternative outcome measures is needed.

Asthma↗
PubMed1991

Clinical usefulness of n-of-1 randomized controlled trials in patients with nonreversible chronic airflow limitation.

To determine if n-of-1 randomized controlled trials (n-of-1 RCT) are useful in the care of patients with nonreversible chronic airflow limitation (CAL). Individual trials had a double-blind, randomized, multiple crossover design. Patients with CAL were recruited from several respirology practices. For each individual trial the main outcome measure was a symptom questionnaire; peak flow measurements were used as a secondary measure. Physicians' plans of management (before and after trials) and confidence in the plans were determined. The proportion of trials that provided a definite clinical or statistical answer was established. Patients were followed, and long-term adherence to decisions based on n-of-1 RCT was examined. A total of 26 n-of-1 RCT in patients with CAL were attempted; 18 of these (69%) were completed. After 17 (94%) of the completed trials clinicians expressed a high degree of confidence in their management plans, confidence that was not, in any case, present before the trial. After 8 n-of-1 RCT (44% of all completed, or 31% of all trials) clinicians decided to stop the drug, which would otherwise have been continued indefinitely. In all 17 of the clinically definite n-of-1 RCT, the management decision that followed the trial was still being adhered to 40 months (on average) after completion of the trial. The results support the feasibility and usefulness of n-of-1 RCT in respirology practice.

Double-Blind Method↗
PubMed1990

The n-of-1 randomized controlled trial: clinical usefulness. Our three-year experience.

OBJECTIVE: To review the feasibility and effectiveness of n-of-1 randomized controlled trials (n-of-1 trials) in clinical practice. DESIGN: Individual trials were double-blind, randomized, multiple crossover trials. The impact of n-of-1 trials was determined by eliciting physicians' plans of management and confidence in those plans before and after each trial. SETTING: Referral service doing n-of-1 trials at the requests of community and academic physicians. OBJECT of ANALYSIS: All trials were planned, started, and completed by the n-of-1 service. MEASURES OF OUTCOME: The proportion of planned n-of-1 trials that were completed and the proportion that provided a definite clinical or statistical answer. A definite clinical answer was achieved if an n-of-1 trial resulted in a high level of physician's confidence in the management plan. Specific criteria were developed for classifying an n-of-1 trial as providing a definite statistical answer. MAIN RESULTS: Seventy-three n-of-1 trials were planned in various clinical situations. Of 70 n-of-1 trials begun, 57 were completed. The reasons for not completing n-of-1 trials were patients' or physicians' noncompliance or patients' concurrent illness. Of 57 n-of-1 trials completed, 50 provided a definite clinical or statistical answer. In 15 trials (39% of trials in which appropriate data were available), the results prompted physicians to change their "prior to the trial" plan of management (in 11 trials, the physicians stopped the drug therapy that they had planned to continue indefinitely). CONCLUSION: We interpret the results as supporting the feasibility and usefulness of n-of-1 trials in clinical practice.

Adult↗
PubMed1989

Should study subjects see their previous responses: data from a randomized control trial.

To test the relative merits of administering questionnaires with previous responses available (the informed condition) or unavailable (the blind condition), we administered blind and informed versions of a quality of life questionnaire (the Chronic Respiratory Disease Questionnaire, or CRQ) in a randomized, double-blind trial of bronchodilators in chronic airflow limitation. The responsiveness of the two methods, as reflected in the p-values associated with salbutamol and theophylline effects were comparable for three of the four dimensions of the CRQ. The data suggested possible increased responsiveness of the informed method for the emotional function dimension of the questionnaire. Changes in the informed CRQ dyspnea and fatigue dimensions showed stronger correlations with changes in spirometry, 6 minute walk distance, and rating of dyspnea after the walk test than did blind administration. Further, changes in all four CRQ dimensions showed stronger correlations with corresponding global ratings using the informed questionnaire. These results suggest that by letting study subjects see their previous responses the validity of subjective measures of health status in clinical trials can be improved.

Administration, Oral↗
PubMed1988

Acute response to bronchodilator. An imperfect guide for bronchodilator therapy in chronic airflow limitation.

We conducted a four-period cross-over randomized trial in which we found that patients with chronic airflow limitation demonstrated symptomatic improvement with both inhaled albuterol and oral theophylline. The response, however, was not uniform. We therefore tested the ability of acute change in forced expired volume in one second (FEV1) following inhaled beta agonist to predict long-term symptomatic response to albuterol and theophylline. We found that the reproducibility of acute change in FEV1 over three repetitions was poor (intraclass correlation 0.17). Furthermore, the mean improvement FEV1 following inhaled albuterol across the three repetitions did not relate closely to symptomatic response to either albuterol or theophylline. We conclude that acute response to inhaled beta agonist is not useful for identifying patients with chronic airflow limitation who are likely to benefit from bronchodilator treatment.

Administration, Inhalation↗
PubMed1988

An N of 1 service: applying the scientific method in clinical practice.

The N of 1 service at our institution acts as a full referral service for clinicians who want a definitive answer to a difficult management question, and an instructional environment for clinicians who have more time and want to learn to run their own N of 1 RCT. The trial design is a double blind, randomized pair, multiple crossover. A number of methodologic issues are discussed, such as appropriateness of the patients problem to N of 1 trials, feasibility, types of measurement, such as clinical objective measurement and quality of life measurement, as well as timing of these measurements. The analysis issues include developing a reporting method which is statistically powerful and understandable to clinicians with little research background. Some of these issues have been well investigated and some have not.

Clinical Trials as Topic↗
PubMed1987

A comparison of Likert and visual analogue scales for measuring change in function.

Many controlled trials rely on subjective measures of symptoms or quality of life as primary outcomes. The relative merits of different response options for these measures is an important, but largely unexplored, issue. Therefore, we compared the responsiveness of seven-point Likert vs visual analogue scales (VAS) in a questionnaire measuring quality of life in chronic lung disease. The VAS and seven-point scale versions of the questionnaire were administered to 28 patients before and after completing an inpatient respiratory rehabilitation program of known benefit. For all four dimensions of the questionnaire (dyspnea, fatigue, emotional function, and mastery) the VAS showed a larger improvement than the seven-point scale when both were standardized on a scale of 0-10. However, in each case the variability of the improvement was greater using the VAS. The difference in improvement between the two scales was not statistically significant. We conclude that the two methods of presenting response options show comparable responsiveness. The ease of administration and interpretation of the seven-point scale recommend its use in clinical trials.

Clinical Trials as Topic↗
PubMed1987

Bronchodilators in chronic air-flow limitation. Effects on airway function, exercise capacity, and quality of life.

We conducted a trial of inhaled salbutamol and orally administered theophylline in patients whose acute response to inhaled salbutamol was less than 25% of their baseline FEV1. Patients underwent 4 treatment periods, each of 2 wk duration, during which they received the following combinations: placebo-placebo, placebo-salbutamol, placebo-theophylline, and salbutamol-theophylline. The 19 patient who completed the study were all males with a mean age of 65 +/- 7.4 yr, mean FEV1 of 1.02 +/- 0.38, and mean VC of 2.73 +/- 0.19. Outcomes included twice-daily recordings of peak flow rates, spirometry, the distance patients could walk in 6 min, and clinical symptoms of dyspnea, fatigue, and emotional function. Clinically important and statistically significant differences between the 4 periods were noted on both physiologic and functional outcomes. For the group as a whole, improvement with inhaled salbutamol and orally administered theophylline was comparable, and additional benefit was gained from a combination of the 2 drugs. We conclude that both inhaled salbutamol and orally administered theophylline can improve airflow obstruction, functional exercise capacity, and quality of life in patients with primarily fixed air-flow limitation.

Aged↗
PubMed1982

Metastatic fungal chorioretinitis developing during Trichosporon sepsis.

A 70-year-old woman treated for acute myelogenous leukemia developed systemic trichosporosis and presumptive trichosporon chorioretinitis. The elevated choroidal lesion appeared during an episode of trichosporon sepsis and increased in size during immunosuppression. Possible retinal vein occlusion and neovascularization were further complications that may be due to the angioinvasive properties of the organism.

Aged↗