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Biomedical subjects

I Mitchell

Publications and source records attributed to I Mitchell.

At least 19 recordsLinked to original sources
PubMed2006

Screening children with asthma for psychosocial adjustment problems: a tool for health care professionals.

OBJECTIVE: To develop a brief questionnaire for health care professionals to use in screening children with asthma for psychosocial adjustment problems. METHOD: The initial version of the Childhood Asthma Resiliency Questionnaire (CARQ) listed 85 items focusing on self-esteem, medical fears, peer relationships, family relations, stress, and depression. The number of items was reduced after focus groups and pilot testing. In pilot tests, 100 children with asthma completed the CARQ. Parents completed the Child Behavior Checklist (CBCL). Another sample of 73 children with mild asthma was also obtained. RESULTS: The total CARQ score was significantly correlated (p < 0.001) with Total Problems, Internalizing, and Externalizing Problems on the CBCL. Children with more hospitalizations and more days of school missed from asthma had significantly higher scores on the CARQ compared to children with less functional morbidity. CONCLUSION: The CARQ appears to be a useful brief measure to help clinicians identify children at risk for problems adjusting to asthma.

Absenteeism↗
PubMed2001

k-Space weighted least-squares algorithm for accurate and fast motion extraction from magnetic resonance navigator echoes.

Navigator echoes provide an effective method to monitor physiological motion, allowing motion artifacts to be suppressed by modifying the data acquisition accordingly. The displacement can be measured directly from the navigator phase using an algorithm suggested by Ahn and Cho (IEEE Trans Med Imaging 1987;MI-6:32-36). Although computationally efficient, it is susceptible to noise, particularly contributions from points at the edges of k-space. A k-space weighted least-squares (kLS) algorithm is proposed which fits a straight line to the motion-induced phase shift. The linear fit is weighted strongly to high SNR points near the k-space center and only weakly to the poor SNR points at the edges of k-space. This algorithm was found to be as efficient as Ahn's algorithm but more robust against noise.

Algorithms↗
PubMed2001

Covert fears and anxiety in asthma and congenital heart disease.

AIM: To compare anxiety, fears and behavioural problems in children with asthma and children with congenital heart disease, and with the normative population. To also review the influence of maternal anxiety, time since diagnosis and severity of disease. DESIGN: Children administered Fear Survey Scale (FSSC-R) and Child Manifest Anxiety Scale (R-CMAS). Mothers given Child Behaviour Checklist (CBCL) and State Trait Anxiety Scale (STAI-S and STAI-T). Normative means and SDs compared with means and SDs for both medical groups. The mother's scores on the STAI-S and STAI-T scales were correlated with the child's scores on the FSSC-R and the R-CMAS. SETTING: Outpatient Asthma and Cardiology multidisciplinary Clinics at a tertiary care paediatric facility, Alberta Children's Hospital. SUBJECTS: Forty children with asthma (aged 6--17 years) were compared with 39 children with congenital heart disease. Intake questionnaires and interviews determined these children to be without obvious psycho-social problems. RESULTS: Children with asthma and children with congenital heart disease had more medical fears, and more physiological anxiety than normative samples. Increased maternal anxiety was correlated in both groups with increased child anxiety, medical fears and behavioural problems in the child. Similarly, increased severity of asthma or cardiac problems was associated with more physiological anxiety and more fears. Less time since diagnosis of the disease adversely affected social interactions in both groups of children. CONCLUSION: Physiological anxiety, medical fears and maternal anxiety are important issues requiring attention in asthma and cardiac disease, even in the absence of obvious psychosocial problems. There may be specific problems with a recent diagnosis of a chronic illness.

Adult↗
PubMed2001

Coronary MR angiography: selection of acquisition window of minimal cardiac motion with electrocardiography-triggered navigator cardiac motion prescanning--initial results.

The authors developed an electrocardiography-triggered M-mode navigator-echo technique to help monitor cardiac motion and identify the period of minimal cardiac motion in the cardiac cycle. Coronary magnetic resonance angiography was performed in eight healthy adult volunteers and one patient with heart disease. To minimize cardiac motion effects, trigger delays were estimated with the navigator-echo technique and two empirical formulas. The quality of images obtained with the different delay times was compared for clarity of depiction of the coronary arteries. Image quality was best with the delay calculated with the navigator-echo technique.

Adult↗
PubMed2000

Cystic fibrosis. End-stage care in Canada.

OBJECTIVES: To determine the circumstances in which individuals with cystic fibrosis (CF) die, the role of different caregivers, and the extent of palliative care for CF patients. DESIGN: Mailed survey of CF physicians. SETTING: CF centers in Canada. PATIENTS: All CF deaths in 1996 known to centers in Canada. RESULTS: The mean age (+/- SD) at death of the 45 individuals included in the study was 25.8 +/- 13.5 years. The major cause of death was respiratory (34 patients; 75.5%). Nutritional concerns were common. Lung transplantation was considered in 42 patients (93.2%), with 7 patients (17.1%) being entered on a list, but it was carried out in only 2 patients (4.4%). Autopsies were performed on only 10 patients (22.2%). Most patients died in hospital (37 patients; 82.2%), and 7 patients (15.6%) died in ICUs while receiving intermittent positive-pressure ventilation. Palliative care was never discussed in 10 patients (25%). In a further 16 patients (40%), it was not discussed until the last month before death. CONCLUSIONS: Respiratory disease remains the most common cause of death in CF patients. Lung transplantation is frequently considered, but most patients die without having had a transplant. Discussions on end-of-life care could be considered sooner.

Adult↗
PubMed1999

Risk factors for death from asthma. Prairie Provinces Asthma Study Group.

BACKGROUND: Asthma mortality rates have increased in Canada and worldwide. Within Canada, the highest rates were seen in the prairie provinces. OBJECTIVE: The objective was to determine risk factors for fatal asthma by comparing those who died of an acute exacerbation with those who attended an emergency department for treatment of asthma. METHODS: The case-control study included all deaths from asthma among those aged 5 to 50 years in Alberta, Saskatchewan and Manitoba from November, 1992 through October, 1995 (cases). The 35 fatalities were matched to 209 controls by age, gender, time of the index event and residence. RESULTS: Cases were more likely than controls to have had severe asthma, an unscheduled physician visit in the past year, a past hospitalization for asthma, and to have been intubated. Both groups reported frequent, regular asthma symptoms. Beta-agonist bronchodilator use was more common among cases, as was use in excess of prescribed amounts. Use of inhaled steroids did not differ between groups. Prior to the index event controls were more likely to report a cold or flu (OR = 0.27; 95% CI: 0.10 to 0.72) and that medications were "not working" (OR = 0.30; 95% CI: 0.12 to 0.71). Cases were more often sad and depressed (OR = 2.88; 95% CI: 1.03 to 8.05). Time between onset/recognition of symptoms and the event was significantly shorter for cases than controls. CONCLUSIONS: Both groups tolerated high levels of regular symptoms, suggesting poor management. Opportunities for intervention existed for both groups near the time of the event. The short time between recognition of symptoms and death suggests patients at increased risk should monitor their condition closely and take action in response to predetermined criteria.

Adolescent↗
PubMed1999

Variable morbidity of respiratory syncytial virus infection in patients with underlying lung disease: a review of the PICNIC RSV database. Pediatric Investigators Collaborative Network on Infections in Canada.

OBJECTIVE: We wished to compare outcomes of respiratory syncytial virus (RSV) infection in children with bronchopulmonary dysplasia (BPD) with those with other pulmonary disorders: cystic fibrosis, recurrent aspiration pneumonitis, pulmonary malformation, neurogenic disorders interfering with pulmonary toilet, and tracheoesophageal fistula. METHODS: Children with RSV infection hospitalized at seven Canadian pediatric tertiary care hospitals in 1993 through 1994 and 9 hospitals in 1994 through 1995 were enrolled and prospectively followed. This study is a secondary analysis of data from this prospective cohort. RESULTS: Of the 1516 patients enrolled the outcomes of 159 with preexisting lung disorders before RSV lower respiratory tract infection constitute this report. There were no significant differences among the 7 groups (BPD, cystic fibrosis, recurrent aspiration pneumonitis, pulmonary malformation, neurogenic disorders interfering with pulmonary toilet, tracheoesophageal fistula, other) for the morbidity measures: duration of hospitalization, intensive care unit (ICU) admission, duration of ICU stay, mechanical ventilation and duration of mechanical ventilation. Patients using home oxygen were more likely to be admitted to the ICU than those who had never or previously used home oxygen (current 57.1%, past 23.8%, never 33.3%, P = 0.03). CONCLUSIONS: Children with other underlying diseases have morbidity similar to those with BPD. Prophylactic interventions against RSV should also be studied in these groups.

Bronchopulmonary Dysplasia↗
PubMed1998

Earlier identification of patients at risk from acetaminophen-induced acute liver failure.

OBJECTIVE: To determine whether the Acute Physiology and Chronic Health Evaluation (APACHE) II system for the measurement of severity of illness is able to provide an accurate risk of hospital death in patients with acetaminophen-induced acute liver failure or identify those patients needing transfer for possible hepatic transplantation. DESIGN: Data for admission (first 24 hrs) APACHE II scores and King's criteria for urgent transplantation were collected prospectively to compare the APACHE II system and the King's criteria for the prediction of death or need for transplantation. SETTING: A nine-bed specialist liver failure unit (LFU). PATIENTS: One hundred two consecutive patients admitted to the LFU with acetaminophen self-poisoning and a prolonged prothrombin time were studied. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: An APACHE II score of > 15 points was associated with a high mortality (13/20 patients, five of whom survived following hepatic transplantation). There was no relation between APACHE II risk and outcome (mean APACHE II risk of death 0.8%, actual hospital mortality 16%). An APACHE II score of > 15 had a similar power of prediction of death as the King's criteria (sensitivity 82% and 65%, respectively; specificity 98% and 99%, respectively), when considering those patients who were transplanted as "deaths." An APACHE II score of > 15 was able to identify four more patients than the King's criteria on the first day of admission to the LFU. CONCLUSIONS: The crude admission APACHE II score correlated well with mortality in patients with acetaminophen-induced acute liver failure. However, the calculated APACHE II risk of death, using the original drug overdose coefficient, was poorly calibrated. Since specialist liver scores are unfamiliar in the general intensive care setting, the use of an APACHE II score might earlier identify more patients at risk of needing a liver transplant, and hence, expedite appropriate transfer to a specialist liver unit.

APACHE↗
PubMed1998

Pseudomonas aeruginosa lasR transcription correlates with the transcription of lasA, lasB, and toxA in chronic lung infections associated with cystic fibrosis.

The role of Pseudomonas aeruginosa quorum-sensing systems in the lung infections associated with cystic fibrosis (CF) has not been examined. The purpose of this study was to determine if genes regulated by the LasR-LasI quorum-sensing system were coordinately regulated by the P. aeruginosa populations during the lung infections associated with CF. We also wanted to ascertain if there was a relationship between the expression of lasR, a transcriptional regulator, and some P. aeruginosa virulence factors during these infections. We extracted RNAs from the bacterial populations of 131 sputa taken from 23 CF patients. These RNAs were blotted and hybridized with probes to P. aeruginosa lasA, lasB, and toxA. The hybridization signals from each probe were ranked, and the rankings were analyzed by a Spearman rank correlation to determine if there was an association between the population transcript accumulations for the three genes. The correlations between the transcript accumulation patterns of pairs of the genes suggested that lasA, lasB, and toxA might be coordinately regulated during CF lung infections. To determine if this coordinate regulation might be due to regulation by LasR, we probed RNAs, extracted from 84 sputa, with the lasR, lasA, lasB, toxA, and algD probes. Statistical analysis indicated that lasR transcript accumulation correlated to lasA, lasB, toxA, and algD transcript accumulations. These results indicated that lasR may at least partially regulate or be coordinately regulated with lasA, lasB, toxA, and algD during the lung infections associated with CF. These results also suggested that the LasR-LasI quorum-sensing system may control the expression of at least some virulence factors in the lungs of patients with CF.

ADP Ribose Transferases↗
PubMed1998

Features that distinguish those who die from asthma from community controls with asthma.

To evaluate risk factors for asthma mortality, an unmatched case-control study was undertaken in the Canadian prairie provinces of Alberta, Saskatchewan, and Manitoba. Those between the ages of 5 and 50 (inclusive) who died from an acute exacerbation of asthma were compared to a control group of people with asthma from the same geographical areas who were contacted using random-digit dialing. Because no deaths occurred among residents less than 15 years old, this analysis was limited to cases and controls between 15 and 50 years old. Of the 38 deaths that occurred between November 1992 and October 1995, data were obtained from next of kin for 35 (92.1%). Of the 210 potential controls that were identified, 142 returned completed questionnaires (67.6%). Cases were more likely than controls to have asthma reported to be severe, to have experienced nocturnal symptoms, to have had cardiopulmonary resuscitation (CPR)/intubation, and to have had more healthcare utilization in the previous year. Medication use was also more common among cases compared to controls. Specific asthma triggers were reported more often for cases than controls; weather changes, excitement, depression, and stress showed the greatest case control differences. Although a number of very strong risk factors for death from asthma were identified, death from asthma is so rare in this age group that it is not possible to label an individual as "likely" to die from asthma. Nonetheless, patients, caregivers, and health professionals should be aware of indicators that would suggest greater risk.

Adolescent↗
PubMed1997

Biological determinants of P300: the effects of a barbiturate on latency and amplitude.

Polich & Kok (1995) (Biological Psychology, 41, 103-146) have recently argued that P300 is not only sensitive to specific 'cognitive' variables, but also to non-specific biological processes such as arousal. Fluctuations in arousal are said to be indexed by an inverse relationship between latency and amplitude. We tested this hypothesis with a drug that decreases arousal-the barbiturate secobarbital sodium. Twelve subjects performed a visual 80-20% oddball task at two levels of stimulus quality and after ingesting the drug (2.9 mg/kg body weight) or a placebo. Reaction time (RT) and P300 were collected simultaneously and the latter was analyzed on both a single trial and average basis. The RT results confirmed that secobarbital interacts with stimulus quality. Secobarbital slowed single trial P300 by about half as much as RT, and this slowing was additive with stimulus quality. Thus the two measures dissociated. Secobarbital did not influence P300 amplitude. Average P300 revealed the same pattern of results, although the size of the latency effects was somewhat attenuated. RT and P300 latency were more strongly correlated than P300 latency and amplitude. We propose that P300 latency reflected the slowing of stimulus evaluation produced by the depressant properties of the drug, and that fluctuations in arousal are not necessarily associated with a simple inverse relationship between P300 latency and amplitude.

Adult↗