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D R King

Publications and source records attributed to D R King.

At least 19 recordsLinked to original sources
PubMed2000

Measuring asthma control. Clinic questionnaire or daily diary?

Daily symptom, peak expiratory flow rate (PEFR), and medication diaries are often used in clinical trials of treatments for asthma on the assumption that they provide a better estimate of clinical status than does a questionnaire completed in the clinic. We conducted a study with the aim of comparing the measurement properties of the clinic-completed Asthma Control Questionnaire with those of the Asthma Control Diary. The diary is composed of questions and response options almost identical to those of the questionnaire, but uses PEFR instead of FEV(1) as the measure of airway caliber. In an observational study, 50 adults with symptomatic asthma attended a McMaster University asthma clinic at 0, 1, 5, and 9 wk to complete the Asthma Control Questionnaire and other measures of asthma status. For 1 wk before each follow-up visit, patients completed the Asthma Control Diary every morning and evening. Concordance between the questionnaire and diary was high (intraclass correlation coefficient [ICC] = 0.87). Both reliability (ICC: questionnaire = 0.90; diary = 0.86) and responsiveness (responsiveness index: questionnaire = 1.06; diary = 0.90; p = 0.005) were better with the questionnaire than with the diary. Correlations between the two instruments and other measures of clinical asthma status were similar and close to a priori predictions. Both the Asthma Control Questionnaire and the Asthma Control Diary are valid instruments for measuring asthma control, but the questionnaire has slightly better discriminative and evaluative measurement properties than does the diary.

Adolescent↗
PubMed2000

Randomized comparison of cisplatin/vincristine/fluorouracil and cisplatin/continuous infusion doxorubicin for treatment of pediatric hepatoblastoma: A report from the Children's Cancer Group and the Pediatric Oncology Group.

PURPOSE: Previous studies demonstrated that chemotherapy with either cisplatin, vincristine, and fluorouracil (regimen A) or cisplatin and continuous infusion doxorubicin (regimen B) improved survival in children with hepatoblastoma. The current trial is a randomized comparison of these two regimens. PATIENTS AND METHODS: Patients (N = 182) were enrolled onto study between August 1989 and December 1992. After initial surgery, patients with stage I-unfavorable histology (UH; n = 43), stage II (n = 7), stage III (n = 83), and stage IV (n = 40) hepatoblastoma were randomized to receive regimen A (n = 92) or regimen B (n = 81). Patients with stage I-favorable histology (FH; n = 9) were treated with four cycles of doxorubicin alone. RESULTS: There were no events among patients with stage I-FH disease. Five-year event-free survival (EFS) estimates were 57% (SD = 5%) and 69% (SD = 5%) for patients on regimens A and B, respectively (P =.09) with a relative risk of 1.54 (95% confidence interval, 0.93 to 2.5) for regimen A versus B. Toxicities were more frequent on regimen B. Patients with stage I-UH, stage II, stage III, or stage IV disease had 5-year EFS estimates of 91% (SD = 4%), 100%, 64% (SD = 5%), and 25% (SD = 7%), respectively. Outcome was similar for either regimen within disease stages. At postinduction surgery I, patients with stage III or IV disease who were found to be tumor-free had no events; those who had complete resections achieved a 5-year EFS of 83% (SD = 6%); other patients with stage III or IV disease had worse outcome. CONCLUSION: Treatment outcome was not significantly different between regimen A and regimen B. Excellent outcome was achieved for patients with stage I-UH and stage II hepatoblastoma and for subsets of patients with stage III disease. New treatment strategies are needed for the majority of patients with advanced-stage hepatoblastoma.

Antibiotics, Antineoplastic↗
PubMed1999

A cost-effective thoracoscopic treatment strategy for pediatric spontaneous pneumothorax.

BACKGROUND: Recent data suggest that children have a higher incidence of recurrence than adults after nonoperative treatment of primary spontaneous pneumothorax (PSP). Video-assisted thoracoscopic surgery (VATS) allows efficacious therapy with significantly less morbidity. We attempt to define the most cost-effective clinically efficacious strategy using VATS to manage pediatric PSP. METHODS: We retrospectively reviewed all admissions to a tertiary care children's hospital for PSP between January 1, 1991 and June 30, 1996. RESULTS: Fifteen children had 29 primary or recurrent PSPs. Mean patient age was 14.8 +/- 1.1 years, boy-girl ratio 4:1, median body mass index 18 (normal, 20-25), and 67% of pneumothoraces left sided. All patients were managed initially nonoperatively: 14 with tube thoracostomy drainage and 1 with oxygen alone. Of the children initially managed nonoperatively, 57% had a recurrent pneumothorax, and 50% of these patients eventually developed contralateral pneumothoraces. Nonoperative treatment for recurrence resulted in a 75% second recurrence rate. In contrast, eight children who underwent operative management had a 9% incidence of recurrence. The total for charges accrued in treating 29 pneumothoraces in these 15 patients was approximately $315,000. In the same population, the estimated charges for initial nonoperative therapy followed by bilateral thoracoscopy after a single recurrence would be $230,000. CONCLUSIONS: A cost-effective treatment strategy for pediatric primary spontaneous pneumothorax is tube thoracostomy at first presentation, followed by VATS with thoracoscopic bleb resection and pleurodesis for patients who experience recurrent pneumothorax.

Adolescent↗
PubMed1999

Multiple endocrine neoplasia type 2A: a 25-year review.

BACKGROUND/PURPOSE: Before 1970, treatment decisions for the thyroid lesions in patients with multiple endocrine neoplasia (MEN) were based on physical findings. For the next 20 years, biological markers assumed a preeminent role, and at present, DNA testing is being used to define the need for therapeutic intervention. This report presents a 25-year review of 22 children with MEN-2A, with a mean follow-up of 12.5 years. METHODS: All 22 children underwent a total thyroidectomy, and four (18%) were rendered permanently hypoparathyroid. Since 1976, however, only one patient (6.7%) has lost parathyroid function. Despite the fact that biological screening studies routinely were performed once a year in the majority of our patients and surgery was recommended for any elevation in the serum calcitonin (CT) levels, medullary carcinoma of the thyroid (MTC) developed in 17 children (77%) and only five had C cell hyperplasia (CCH). Thirteen of the 17 had macroscopic tumor described by the pathologist, evidence of recurrent disease (MTC-REC) has developed in four children (24%). RESULTS: There was considerable overlap in both the basal and stimulated CT levels among the five children with CCH, the 13 with localized MTC (MTC-NED), and the four who later had recurrent MTC. The basal calcitonin levels were between 25 and 110 (mean, 58) in the CCH patients, 30 to 1,130 (mean, 184) in the MTC-NED group, and 108 to 201 (mean, 140) in those with recurrent MTC. The corresponding stimulated calcitonin levels were 45 to 417 (mean, 179) in CCH, 111 to 9,510 (mean, 1,407) in MTC-NED, and 449 to 5,093 (mean, 3,383) in MTC-REC. CONCLUSIONS: (1) Basal and pentagastrin-stimulated CT levels did not reliably discriminate between CCH and MTC and should not be used to define the timing of thyroid surgery in children with MEN-2A. (2) Surgical therapy should be undertaken early in childhood on the basis of molecular genetic testing. (3) Postoperative complications are infrequent in the modern era.

Adolescent↗
PubMed1999

Generic and specific measurement of health-related quality of life in a clinical trial of respiratory rehabilitation.

The purpose of this study was to compare the performance of measures of health-related quality of life in a randomized controlled trial of respiratory rehabilitation versus conventional community care for patients with chronic airflow limitation. The study included 89 stable patients with moderate to severe chronic airflow limitation with measurement of health status at 12, 18, and 24 weeks. Outcomes included two disease-specific (the Oxygen Cost Diagram and the Chronic Respiratory Questionnaire [CRQ]) measures, a generic health profile (the Sickness Impact Profile [SIP]), and two utility measures (the Standard Gamble and the Quality of Well-Being index [QWB]). Of the measures, only the four domains of the CRQ (dyspnea, fatigue, mastery, and emotional function) showed statistically significant differences (P < or = 0.05) between treatment and control groups. Correlation between change in the CRQ and change in other relevant measures, including the 6-minute walk test and global ratings of change in dyspnea, fatigue, and emotional function were generally weak to moderate (from 0.19 to 0.51). All correlations between change in the QWB, SIP, and Standard Gamble and other measures were very weak or weak (up to 0.30). Correlation between change in the three generic measures were all very weak (<0.15). The results suggest that unless investigators include responsive and valid disease-specific measures of health-related quality of life in controlled trials in chronic diseases, they risk misleading conclusions about the effect of treatments on health status.

Health Care Surveys↗
PubMed1999

Development and validation of the Mini Asthma Quality of Life Questionnaire.

The 32-item Asthma Quality of Life Questionnaire (AQLQ) has shown good responsiveness, reliability and construct validity; properties that are essential for use in clinical trials, clinical practice and surveys. However, to meet the needs of large clinical trials and long-term monitoring, where efficiency may take precedent over precision of measurement, the 15-item self-administered MiniAQLQ has been developed. The MiniAQLQ was tested in a 9-week observational study of 40 adults with symptomatic asthma. Patients completed the MiniAQLQ, the AQLQ, the Short Form (SF)-36, the Asthma Control Questionnaire and spirometry at baseline, 1, 5 and 9 weeks. In patients whose asthma was stable between clinic visits, reliability was very acceptable for the MiniAQLQ (intraclass correlation coefficient (ICC)=0.83), but not quite as good as for the AQLQ (ICC=0.95). Similarly, responsiveness in the MiniAQLQ (p=0.0007) was good but not quite so good as for the AQLQ (p<0.0001). Construct validity (correlation with other indices of health status) was strong for both the MiniAQLQ and the AQLQ. Criterion validity showed that there was no bias between the instruments (p=0.61) and the correlation between them was high (r=0.90). The Mini Asthma Quality of Life Questionnaire has good measurement properties but they are not quite as strong as those of the original Asthma Quality of Life Questionnaire. The choice of questionnaire should depend on the task at hand.

Adolescent↗
PubMed1999

Development and validation of a questionnaire to measure asthma control.

International guidelines on asthma management indicate that the primary goal of treatment should be optimum asthma control. The aim of this study was to develop and validate the Asthma Control Questionnaire (ACQ). The authors generated a list of all symptoms used to assess control and sent it to 100 asthma clinicians who were members of guidelines committees (18 countries). They scored each symptom for its importance in evaluating asthma control. From the 91 responses, the five highest scoring symptoms were selected for the ACQ. In addition, there is one question on beta2-agonist use and another on airway calibre (total questions=7). The ACQ was tested in a 9-week observational study of 50 adults with symptomatic asthma. The ACQ and other measures of asthma health status were assessed at baseline, 1, 5 and 9 weeks. In patients whose asthma was stable between clinic visits, reliability of the ACQ was high (intraclass correlation coefficient (ICC)=0.90). The questionnaire was very responsive to change in asthma control (p<0.0001). Cross-sectional and longitudinal validity were supported by correlations between the ACQ and other measures of asthma health status being close to a priori predictions. In conclusion, the Asthma Control Questionnaire has strong evaluative and discriminative properties and can be used with confidence to measure asthma control.

Adolescent↗
PubMed1999

Validation of a standardized version of the Asthma Quality of Life Questionnaire.

BACKGROUND: In the original 32-item Asthma Quality of Life Questionnaire (AQLQ), five activity questions are selected by patients themselves. However, for long-term studies and large clinical trials, generic activities may be more appropriate. METHODS: For the standardized version of the AQLQ, the AQLQ(S), we formulated five generic activities (strenuous exercise, moderate exercise, work-related activities, social activities, and sleep) to replace the five patient-specific activities in the AQLQ. In a 9-week observational study, we compared the AQLQ with the AQLQ(S) and examined their measurement properties. Forty symptomatic adult asthma patients completed the AQLQ(S), the AQLQ, the Medical Outcomes Survey Short Form 36, the Asthma Control Questionnaire, and spirometry at baseline, 1, 5, and 9 weeks. RESULTS: Activity domain scores (mean +/- SD) were lower with the AQLQ (5.7 +/- 0.9) than with the AQLQ(S) (5.9 +/- 0.8; p = 0.0003) and correlation between the two was moderate (r = 0.77). However, for overall scores, there was minimal difference (AQLQ, 5.4 +/- 0.8; AQLQ(S), 5.5 +/- 0.8; r = 0.99). Reliability (AQLQ intraclass correlation coefficient, 0.95; AQLQ(S) intraclass correlation coefficient, 0.96) and responsiveness (AQLQ, p < 0.0001; AQLQ(S), p < 0.0001) were similar for the two instruments. Construct validity (correlation with other measures of health status and clinical asthma) was also similar for the two instruments. CONCLUSIONS: The AQLQ(S) has strong measurement properties and is valid for measuring health-related quality of life in asthma. The choice of instrument should depend on the task at hand.

Activities of Daily Living↗
PubMed1998

Aortobronchial fistula after expandable metal stent insertion for pediatric bronchomalacia.

Indications for using expandable metal stents (EMS) for airway disease have expanded considerably during the past decade. Complications have been infrequent but can be potentially life threatening. There are four reported instances of vascular bronchial fistula after Gianturco EMS insertion for managing airway disease in adults. The authors report a case of an aortobronchial fistula in a pediatric patient after Palmaz EMS insertion for treatment of bronchomalacia. A 14-year-old boy with severe scoliosis underwent left mainstem bronchus insertion of two Palmaz stents in tandem for correction of complete bronchial obstruction caused by vascular compression. Three weeks later fatal hemoptysis from an aortobronchial fistula developed. Elective EMS insertion for treatment of airway obstruction secondary to compression by vascular structures should be approached with caution. EMS placement should be reserved for situations in which there is no other reasonable surgical alternative.

Adolescent↗
PubMed1998

Measuring quality of life in children with rhinoconjunctivitis.

OBJECTIVE: The objective of this study was to develop, pretest, and validate a questionnaire to measure quality of life in children with seasonal allergic rhinoconjunctivitis (SAR). METHODS (DEVELOPMENT STUDY): Thirty-four children with SAR were enrolled from summer camps, notices in the media, and an allergy clinic (Southern Ontario). After generating a pool of 48 potentially important quality of life items, the children identified the ones that they experienced with their SAR and scored each for bother (1 = a little bothered to 4 = extremely bothered). Items identified most frequently and with the highest bother score were included in the Paediatric Rhinoconjunctivitis Quality of Life Questionnaire (PRQLQ). The PRQLQ was pretested for ease completion and accuracy of understanding. RESULTS (DEVELOPMENT STUDY): The PRQLQ has 23 items in five domains (nose symptoms, eye symptoms, practical problems, other symptoms, and activities). Responses are given on a seven-point scale, and children are asked to score their experiences during the previous 7 days. METHODS (VALIDATION STUDY): Seventy-five children with symptomatic SAR were enrolled from notices in the media and a pediatric allergy clinic (Austin, Tex.). A single cohort design was used, with children assessed at 0, 1, and 3 weeks. The PRQLQ was administered to the children by a trained interviewer at 1 and 3 weeks. A conventional nasal symptom daily diary was completed for 1 week before each of these clinic visits. Global ratings were completed at the final visit. RESULTS (VALIDATION STUDY): In patients who were stable between clinic visits, the PRQLQ demonstrated good reliability (intraclass correlation coefficient = 0.93). The questionnaire was very responsive to change (p < 0.001) and was able to differentiate between patients who were in a stable clinical state and those whose clinical state changed between visits (p = 0.005). Correlations between the PRQLQ and diary scores were close to predicted and supported both the cross-sectional and longitudinal validity of the PRQLQ. CONCLUSIONS: The PRQLQ measures the quality of life impairments important to children with SAR. Children provide reliable and accurate responses, the measurement properties are strong, and the questionnaire can be used with confidence in clinical trials, clinical practice, and surveys.

Child↗
PubMed1997

Pulmonary function is compromised in children with mediastinal lymphoma.

PURPOSE: Lymphomas account for nearly 20% of the malignancies in childhood and the majority of patients with Hodgkin's Disease (HD) and non-Hodgkin's lymphoma (NHL) have radiological evidence of mediastinal involvement at presentation. Children with mediastinal tumors are at risk for the development of lethal airway obstruction during general anesthesia. This study quantitates the degree of the airway obstruction and the functional significance of tracheal compression in a cohort of 51 children with HD and NHL. RESULTS: Thirty patients with HD (mean age, 14.6 years) and 21 with NHL (mean age, 9.2 years) were included in this study. Twenty-five children (49%) had respiratory symptoms at the time of presentation. Respiratory complaints were much more common in children with NHL (76%) when compared with those with HD (30%). Pulmonary function was also significantly worse in the NHL patients who had a mean upright forced vital capacity (FVC) of 66 +/- 21%. The comparable value for the children with HD was 85 +/- 15% (P = .031). Patients with respiratory symptoms at presentation had both obstructive and restrictive deficits of pulmonary function. Their mean upright forced expiratory volume in 1 second (FEV1) was 69 +/- 22% and the FVC was 69 +/- 18%. Children with large mediastinal masses also had significantly decreased pulmonary function compared with those with small tumors. The upright FEV1 for these two groups was 72 +/- 18% versus 98 +/- 15% (P = .016). Their FVC values were 68 +/- 20% and 91 +/- 17%, respectively (P = .049). Mean tracheal compression was measured at 44% in the children with large tumors versus 27% for those with small lesions (P = .048). CONCLUSION: Children with mediastinal lymphomas have both obstructive and restrictive deficits on pulmonary function testing. Pulmonary function is significantly decreased in patients with NHL, children who present with respiratory symptoms, and those with very large mediastinal masses (mediastinal mass ratio > 45%). The extent of tracheal compression correlates with the size of the mediastinal mass.

Adolescent↗
PubMed1997

Prognostic classification for esophageal atresia and tracheoesophageal fistula: Waterston versus Montreal.

Since 1962, the Waterston classification has been used to stratify neonates who have esophageal atresia (EA) and/or tracheoesophageal fistula (TEF) into prognostic categories based on birth weight, the presence of pneumonia, and the identification of other congenital anomalies. In response to advances in neonatal care, the surgeons from the Montreal Children's Hospital proposed a new categorization system in 1993 in an attempt to define the current risk factors for patients who have EA/TEF. In the Montreal experience only two characteristics independently affected survival: preoperative ventilator dependence and associated major anomalies. The goal of this study was to determine which system had the greatest validity for the evaluation of prognosis in our patients with EA/TEF. The charts of 94 patients who had EA/TEF treated between 1972 and 1991 were reviewed. Patients were classified using both the Waterston and Montreal systems. Groups were compared with Fisher's Exact test using a 95% confidence level for statistical significance. Eleven infants were ventilator dependent preoperatively; 62 children had major associated anomalies, 8 of which were considered life threatening. Sixteen children died within 4 years, eight during their initial hospital stay. Five of the eight early postoperative deaths occurred in the highest-risk patients (Waterston C or Montreal II). Analysis was performed for multiple risk factors and mortality. As in the Montreal study, the presence of life-threatening and major congenital anomalies represented significant risk factors for death. Pulmonary disease as delineated by ventilator dependence appeared to be more accurate than pneumonia. This study confirms the accuracy of the Montreal classification in defining prognosis for EA/TEF. The Montreal system more accurately identifies children at highest risk than the Waterston classification.

Abnormalities, Multiple↗
PubMed1997

Clinical impact versus factor analysis for quality of life questionnaire construction.

OBJECTIVE: We have compared two philosophically different methods for selecting items for a disease-specific quality of life questionnaire. The impact method selects items that are most frequently perceived as important by patients whereas the psychometric method (factor analysis) selects items primarily according to their relationships with one another. PATIENTS: 150 adults with symptomatic asthma and a wide range of disease severity were enrolled from asthma clinics and notices in the local media. STUDY DESIGN: From a list of 152 items that are potentially troublesome to patients with asthma, the patients identified those items they had experienced in the previous year and scored the importance of each on a five-point scale. For the impact method, items that were identified most frequently and that scored the highest were included in the final instrument. For the psychometric method, factor analysis was performed after highly skewed items had been removed. Items with high factor loading were included in the final instrument. RESULTS: The impact method resulted in a 32-item instrument and psychometric analysis in one with 36 items. Twenty items were common to both instruments. The psychometric approach discarded the highest impact emotional function and environmental items and included in their place lower impact items mainly associated with fatigue. CONCLUSIONS: Although some items were the same for both methods, there were also some important differences. Different approaches to item reduction led to appreciably different instruments.

Adolescent↗
PubMed1997

Timing and magnitude of decline in alpha-fetoprotein levels in treated children with unresectable or metastatic hepatoblastoma are predictors of outcome: a report from the Children's Cancer Group.

PURPOSE: We analyzed data on 31 children with primary unresectable or metastatic hepatoblastoma (HB) to investigate possible prognostic correlations between the serum level of alpha-fetoprotein (AFP), its changes during treatment, and outcome. PATIENTS AND METHODS: Patients were treated according to the Children's Cancer Group (CCG) protocol 823F, which included an initial surgery before eight courses of chemotherapy that consisted of cisplatin immediately followed by a continuous infusion of doxorubicin. Four courses were given before and four after the second surgery. AFP levels were measured before treatment, before and after second surgery, and at the end of treatment. RESULTS: Twenty-four of 31 patients showed a decline of > or = 1 log in AFP levels before second surgery (early responders). By the end of treatment, there were 16 patients, all early responders, without clinical or radiographic evidence of tumor and with normal AFP levels. Fifteen of those 16 had a decline of > or = 2 logs in AFP before second surgery (large early response). Of the 15 patients who failed to respond to treatment, 10 died, among whom only one patient had a large early response. A large early response was the strongest independent predictor of outcome in a univariate and multivariate Cox regression model, and patients with such a response had the best survival (P < .0001). CONCLUSION: For children with unresectable or metastatic HB, early changes in AFP levels are a reliable predictor of outcome and can be used for identification of poor responders to treatment, ie, patients whose AFP level fails to decrease 2 logs before second surgery should be considered for alternative treatment.

Child↗
PubMed1996

Fluoroacetate content of some species of the toxic Australian plant genus, Gastrolobium, and its environmental persistence.

Gas chromatography confirmed the relatively high concentrations of fluoroacetate found in toxic Gastrolobiums, a genus of indigenous Australian plants. Fluoroacetate concentration in these plants ranged from 0.1 to 3875 micrograms/g (ppm) dry weight, with young leaves and flowers containing the highest concentrations. However, there was considerable intrastand variation between individual plants of at least two species with coefficients of variation ranging from 94% to 129%. Despite the high concentrations of fluoroacetate in many species, only one of nine soil samples collected from beneath these plants contained fluoroacetate. None of the 16 water samples collected from nearby streams and catchment dams contained fluoroacetate. This suggests that fluoroacetate does not persist in this environment. Fluoroacetate was also found in the genus Nemcia, and very low levels of fluoroacetate (ng/g) were detected in the foodstuffs, tea and guar gum. The latter indicates that other plant species may produce biologically insignificant amounts of fluoroacetate.

Australia↗
PubMed1996

Intrathoracic cystic hygroma: a report of three cases.

Cystic hygromas are relatively uncommon benign tumors of the lymphatic system. The lesions frequently are apparent at birth, and more than 90% are detected before the end of the second year of life. Most commonly, cystic hygroma presents as a soft tissue mass in the posterior triangle of the neck, and only rarely does it extend into the mediastinum. Isolated intrathoracic hygromas are exceedingly rare and have been reported infrequently among children. Herein the authors review three cases of intrathoracic cystic hygroma, spanning a period of 30 years at their institution.

Child, Preschool↗
PubMed1996

Does the colon adopt small bowel features in a small bowel environment?

BACKGROUND: Isoperistaltic colon interposition is one of several surgical options available in the treatment of short bowel syndrome. It functions primarily by slowing the rapid intestinal transit that follows small bowel resection (SBR). Previous studies have interposed distal colonic segments and although there is evidence of adaptation by the interposed colon it is not known whether these segments develop histologic or functional small bowel characteristics. METHODS: In this study evidence was sought of metaplasia in the interposed segments after 80% SBR and, because proximal colon is a midgut derivative, the differences between proximal and distal colonic segments were examined. RESULTS: There was no qualitative histological evidence of metaplasia by the interposed segments. There was a significant increase in crypt depth, mucosal thickness and maltase concentration of the interposed segments compared with the nontransposed colon of the controls. The maltase concentations were increased to the extent that they were not significantly different from the concentration present in normal ileum. CONCLUSIONS: Although there was no gross evidence of small bowel intestinalization by the interposed segments, there was evidence of adaptation which was not merely an extension of the adaptive process seen after SBR alone. These changes resulted in the colon taking on some small bowel features. There was no significant difference between proximal vs distal interposed segments.

Adaptation, Physiological↗