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Biomedical subjects

I Mitchell

Publications and source records attributed to I Mitchell.

120 records · Page 7Linked to original sources
PubMed1972

Patients with acute poisoning seen in a general medical unit (1960-71).

A review of the 637 out of a total of 941 consecutive cases of acute poisoning admitted to an acute medical unit without special facilities for the treatment of poisoning has shown that despite considerable limitations in the medical, nursing, and laboratory facilities available the results compare favourably with those reported from specialized units.

Adult↗
PubMed1970

Teratogenic evaluation of 2,4,5-T.

The herbicide 2,4,5-trichlorophenoxyacetic acid is teratogenic and fetocidal in two strains of mice when administered either subcutaneously or orally and in one strain of rats when administered orally. The incidences of both cystic kidney and cleft palate were increased in the C57BL/6 mice as well as the incidence of cleft palate in the AKR mice. The incidence of cystic kidney was also increased in the rats. In addition, an increase in the ratio of liver weight to body weight in the mouse fetus and the occurrence of hemorrhagic gastrointestinal tract in the rat fetus suggest that this compound also has fetotoxic properties.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

Bronchial casts of human lungs using negative pressure injection.

Negative-pressure casting techniques have been used for obtaining silicone rubber casts of the avian respiratory system, which contains minute air capillaries, noncompressible hollow bones, and highly flexible air sacs. The possibilities of this technique for the study of human airway diseases, which present technical difficulties similar to those of avian lungs, are investigated here. Left lungs from patients with various obstructive lung diseases or with normal lungs were fixed at autopsy under 25 cm H2O airway pressure with 2.5% phosphate-buffered glutaraldehyde. Cannulated, isolated lobes were placed in a vacuum chamber, and Dow Corning 734 RTV silicone elastomer, diluted with 10% low-viscosity silicone oil, was introduced into the airways at--10 kPa. Following complete polymerization, the tissue was microdissected to reveal the lung cast in situ, and histological sections were obtained for correlative studies. The tissue was then macerated in 5.25% sodium hypochlorite. The total time from fixation to finished cast was 3-4 days. Linear shrinkage of the elastomer was less than 1% in glutaraldehyde or water and between 1 and 2% in bleach. The negative-pressure injection technique enabled complete and accurate filling of airways to the alveolar duct level at physiological pressures and provided good delineation of blind cavities such as obstructed airways or ecstatic mucous gland ducts. The technique proved useful for the study of obstructive lung disease and should also prove useful for modelling aerosol deposition in diseased lungs.

Bronchi↗
PubMedDate not supplied

Factors that influence emergency department visits for asthma.

BACKGROUND: Asthma can usually be controlled through allergen avoidance and/or appropriate medication. An emergency department visit for an acute exacerbation of asthma often represents a breakdown in asthma management. Emergency department treatment results in significant health care expenditures and reflects a compromised quality of life. OBJECTIVES: To identify risk factors associated with an emergency department visit for asthma. METHODS: This case-control study compared 299 people (76% of 390 cases contacted) who attended one of two emergency departments in Alberta in 1992 and 1993 for an acute exacerbation of asthma (cases) with 212 unmatched community controls with asthma who were located by random digit dialing. Cases and controls were asked to complete a mailed questionnaire to obtain data regarding severity, visits to doctors and emergency departments, medication use, allergies and other triggers, and smoking history. Data analysis included bivariate analysis of risk factors and multivariate model development using logistic regression. RESULTS: The response rate was similar between cases and controls. Cases were younger than controls (odds ratio [OR] 2.16, 95% CI 1.34 to 3.48) and more often reported their asthma to be severe (OR 4.25, 95% CI 2.24 to 8.06), and had experienced nocturnal symptoms (stratified OR range 1.36 to 6.82). Cases used more health care services in the previous year, had been admitted to hospital at some time for asthma (OR 1.62, 95% CI 1.10 to 2.38) and used more medication than controls. CONCLUSIONS: Physicians and other health care workers should be sensitive to the risk factors and target interventions to high risk individuals.

Acute Disease↗
PubMedDate not supplied

Physician asthma management practices in Canada.

OBJECTIVES: To establish national baseline information on asthma management practices of physicians, to compare the reported practices with the Canadian Consensus recommendations and to identify results potentially useful for interventions that improve physician asthma management practices. DESIGN: National, stratified cross-sectional survey. SETTINGS: The 10 provinces and two territories of Canada, from 1996 to 1997. PARTICIPANTS: Questionnaires were sent to 4489 physicians stratified by province/territory and specialty group (family/general practice, respirology, internal medicine, pediatrics and allergy/immunology); 2605 responses were received. OUTCOME MEASURES: Methods for the diagnosis, treatment, education and follow-up of patients with asthma ('asthma management practices'). RESULTS: Significant variations existed among the five specialty groups in asthma management practices. A low use of objective measures of airflow limitation to assist with diagnosis was found among some respondents (mostly family physicians). Up to 40% of physicians regarded the daily fixed dosing (three or four times a day) of inhaled, short acting beta2-agonist as 'first-line therapy' for moderate to severe asthma. A minority of physicians reported using written action plans for patients or referring them to other health professionals for asthma education. Insufficient time during appointments and a perceived lack of appropriate educational materials were frequently cited as reasons for not providing asthma education. The perceived knowledge of the Canadian Consensus recommendations varied among physicians but was lowest among nonspecialists. CONCLUSIONS: The survey showed variations in certain aspects of the management of asthma by physicians. The findings will help to target specific areas for future physician education programs and other behavioural change strategies.

Asthma↗
PubMedDate not supplied

Postmortem serum levels of tryptase and total and specific IgE in fatal asthma.

Sera were obtained postmortem from 55 subjects classified into three groups; death due to asthma (FA, n = 21), asthmatic but death not due to asthma (NFA, n = 24) and a nonasthmatic control group (NAC, n = 10). A full autopsy was performed on all cases and a medical history, including details of allergies, was obtained by questionnaire from the next of kin. Grading of asthma severity by either questionnaire or autopsy was comparable (tP = 0.435, p > 0.05) and the mean pathology-grade was significantly higher for the FA group (3.375) compared to the NFA group (2.375), p < 0.05. Tryptase was elevated (> 2.0 micrograms/L) in 21/55 sera (38%) and there was no significant difference between the groups. ROC plots showed that tryptase levels did not discriminate between the FA and NFA groups, even if specimens were collected within 24 hours after death. Total IgE was significantly elevated in the FA group (geometric mean 140.3 kU/L) compared to the other two groups (NFA 30.2 kU/L, NAC 9.4 kU/L), p = 0.05. Fatal asthmatics also had a greater positivity (67%) to a screen for common inhalant allergens than did the other groups (NFA 30%, NAC 20%). Sera with a positive screen were tested against a panel of 10 common aero-allergens. Each sample was then assigned a number (N) and a score (S), dependent on either the number of allergens positive (N) or the total sum of pluses for all allergens (S). Both the N and S values were higher for the FA group (N = 98, S = 264) than the NFA group (N = 52, S = 151) and NAC group (N = 4, S = 8). The ratio (S/N) which gives an index (I) was 2.69, 2.90, and 2.00, respectively. Tryptase was poorly correlated to the total IgE level (r = 0.036); however, mean values for N and S were significantly different (N 6.81, S 4.50, and N 19.25, S 11.5, p < 0.05) for sera with tryptase levels < 2.0 or > or = 2.0 micrograms/L, respectively. We conclude that total and specific IgE may be useful predictors of asthma severity but that postmortem tryptase is not useful in the diagnosis of a fatal asthmatic attack.

Adolescent↗
PubMedDate not supplied

Gender differences in asthma in childhood and adolescence.

Asthma is a common chronic disease that can have a significant impact on individuals' daily lives. It is characterized by wheeze, shortness of breath, chest tightness, and cough secondary to airway inflammation and hyperresponsiveness to a variety of stimuli. Asthma is far more common in boys than girls during early childhood. The prevalence equalizes between the genders during adolescence and then switches to a female predominance in adulthood. This article reviews the epidemiology and possible pathophysiologic mechanisms for the observed differences in asthma between the genders. In practical terms, the impact of asthma may be different according to gender in terms of daily activities for children and adolescents. The implications of gender differences in asthma for the health professional will also be discussed.

Adolescent↗