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Dive into the research topics where J. Baskerville is active.

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Featured researches published by J. Baskerville.


The Journal of Allergy and Clinical Immunology | 1989

Bioequivalent doses of budesonide and prednisone in moderate and severe asthma

John H. Toogood; J. Baskerville; Barbara Jennings; Neville M. Lefcoe; S-A. Johansson

We determined the relative antiasthmatic and systemic glucocorticoid potencies of inhaled budesonide (BUD) versus morning-dose oral prednisone (PRED) in 34 adult patients with asthma over a dose range extending from conventional to high and potentially toxic levels, 3.2 mg of BUD or 40 mg of PRED per day. Changes in symptom frequency and severity, FEV1, and peak expiratory flow rate were measured during a double-blind, double-dummy controlled, crossover protocol. The drugs proved equally effective, provided a sufficient dosage was administered. The dose required to eliminate recurrently disabling asthma relapses in these patients was about 2.0 mg of BUD per day or greater than 40 mg of PRED per day. On the average, BUD doses greater than or equal to 1.84 mg/day/70 kg adult (26.3 micrograms/kg/day) exhibited systemic effects on the 8 AM serum cortisol level and blood eosinophil count equivalent to greater than or equal to 15 mg of PRED per day. The latter doses are known to be associated with steroid-induced complications, such as osteoporosis. However, the level of systemic glucocorticoid activity produced by any particular dose of BUD in these patients was consistently much lower than that produced by the dose of PRED needed to achieve an equivalent level of antiasthmatic response. Thus, the use of high-dose inhaled BUD appears clinically reasonable and ethically acceptable in patients with severe asthma in whom the alternative is their continuing dependency on PRED.


The Journal of Allergy and Clinical Immunology | 1982

Influence of dosing frequency and schedule on the response of chronic asthmatics to the aerosol steroid, budesonide

John H. Toogood; J. Baskerville; Barbara Jennings; Neville M. Lefcoe; S.A. Johansson

The influence of various dosing regimens on the response of asthmatic patients to aerosol steroid was investigated. Budesonide, a topically active corticosteroid like beclomethasone dipropionate, was given q.i.d. or b.i.d., in the morning or A.M./P.M., at doses of 400, 800, and 1600 micrograms/day. Each patient (n = 34) took every treatment combination for 2 wk. The antiasthmatic and systemic effects, measured by changes in peak expiratory flow rate (PEFR), blood eosinophils, and serum cortisol levels increased approximately linearly on log dose budesonide (p less than 0.0005). Systemic effects of the drug were nonsignificant at low dosage. At high dosage, morning dosing conserved hypothalamic-pituitary-adrenal function, but at the cost of a marginal reduction in efficacy (delta PEFR, p = 0.12). Having the dose frequency reduced the antiasthmatic potency of the drug, i.e., PEFR fell by an amount equivalent to approximately eightfold reduction in daily dosage (p = 0.002). This effect was not evident when asthma was in remission but became so with asthma in relapse. Overall, the q.i.d. A.M./P.M. regimen showed the best risk-benefit relationships. The data indicate (1) that reductions in dose frequency made with the hope of improving patient compliance and thus conserving the drugs long-term efficacy are likely to lead to the reverse effect, (2) that the clinician can conserve a better balance of risk vs benefit by titrating dosage in terms of puffs per dose rather than doses per day, and (3) that patients can increase the antiasthmatic efficacy of this aerosol steroid without any increase in drug costs (or apparent risk) by simply increasing dosing frequency. These therapeutic considerations probably apply to some or all of the other topically active steroids currently used to treat asthma.


The Journal of Allergy and Clinical Immunology | 1995

Bone mineral density and the risk of fracture in patients receiving long-term inhaled steroid therapy for asthma

John H. Toogood; J. Baskerville; A.E. Markov; Anthony B. Hodsman; Lawrence J. Fraher; Barbara Jennings; R.G. Haddad; D. Drost

To determine whether high-dose or prolonged inhaled steroid therapy for asthma increases a patients risk of osteoporosis and fracture, we measured bone density in 26 men and 43 women (41 postmenopausal, all of whom had received supplemental estrogen therapy) after treatment with an inhaled steroid for 10.1 +/- 5.5 years and oral prednisone for 10.7 +/- 9.7 years (mean +/- SD). Most had stopped receiving prednisone since commencing the inhaled steroid therapy. We found that bone densities (adjusted for age and sex to yield a z score) were lower in association with higher daily doses of inhaled steroid (p = 0.013 ANCOVA) and with the duration of past prednisone therapy (p = 0.032). Larger cumulative inhaled steroid doses were associated with higher bone densities (p = 0.002) and a reduction in the numbers of patients at risk of fracture. Bone density also increased with the amount of supplemental estrogen therapy (p = 0.058) and, at equivalent levels of inhaled and oral steroid use, women showed higher bone density z scores than did men. Women with a lifetime dose of inhaled steroid greater than 3 gm had normal bone density regardless of the amount of past or current prednisone use or the current dose of inhaled steroid. These data indicate that the daily dose, but not the duration, of inhaled steroid therapy may adversely affect bone density, and that estrogen therapy may offset this bone-depleting effect in postmenopausal women.


The Journal of Allergy and Clinical Immunology | 1991

Effects of dose and dosing schedule of inhaled budesonide on bone turnover

John H. Toogood; Barbara Jennings; Anthony B. Hodsman; J. Baskerville; Lawrence J. Fraher

To assess whether the use of larger than usual doses of inhaled steroid to treat severe asthma may adversely affect bone turnover and whether such an effect may be mitigated by altering the dose schedule, we investigated the effects of budesonide (BUD) on serum osteocalcin and the urinary output of hydroxyproline and calcium. Healthy adults were administered 1.2 or 2.4 mg of BUD per day (N = 40) or placebo (N = 8) in a crossover, double-blind comparison of morning versus diurnal dosing schedules for 1 month each. Both BUD doses reduced the 24-hour urinary free-cortisol output (p less than 0.001) and serum osteocalcin (p less than 0.001). The larger dose reduced the morning serum cortisol levels (p = 0.002). Neither dose increased the 8 AM urinary calcium or hydroxyproline output. Osteocalcin and plasma cortisol levels were higher on morning than on diurnal dosing (p = 0.01). The 24-hour urinary free-cortisol output was the same with either schedule (p = 0.96). Additional study is required to assess the clinical importance of the inhibitory effect of BUD on bone formation, as evidenced by the reduction in osteocalcin levels. Of concern is the possibility of serious bone complications resulting from the long-term use of inhaled steroid, particularly in growing children or patients in whom other risk factors for osteoporosis are present. The clinical advantage, if any, of morning dosing remains questionable.


Neurology | 1989

The influence of pregnancy on disability from multiple sclerosis A population‐based study in Middlesex County, Ontario

Brian G. Weinshenker; Walter J. Hader; W. Carriere; J. Baskerville; George C. Ebers

We analyzed the effect of pregnancy on long-term disability resulting from multiple sclerosis in 185 women ascertained through a retrospective population-based survey of MS in Middlesex County, Ontario, Canada. There was no association between disability and total number of term pregnancies, timing of pregnancy relative to onset of MS, or either onset or worsening of MS in relation to a pregnancy. The mean number of pregnancies both before and after onset of MS was no different among groups stratified according to disability. This study addresses some of the difficulties inherent in studying the effect of pregnancy on disability resulting from MS.


Neurology | 1996

Meta-analysis of the placebo-treated groups in clinical trials of progressive MS

Brian G. Weinshenker; Maher Issa; J. Baskerville

The behavior of the control groups can substantially affect the power and outcome of a clinical trial.We report a meta-analysis of the control groups of four large, double-blind, placebo-controlled clinical trials of immunosuppressive treatment of progressive MS to address the sensitivity of five hypothetical definitions of treatment failure (TF). The rate of TF in the aggregate control groups (n = 427) was 31% when a confirmed increase of 1.0 expanded disability status scale (EDSS) point was required at the end of the trial; it was 51% when confirmation was not required and TF was allowed at the first point where the criteria for TF were met. The rate of confirmed TF was 45% when the TF criteria were indexed to baseline EDSS, accounting for the observed differences in staying times at different EDSS levels. We developed models predicting TF in progressive MS. In addition to baseline EDSS, the pyramidal functional score and, for one definition, brainstem functional score were associated with probability of TF. NEUROLOGY 1996;46: 1613-1619


Neurology | 1990

A comparison of sporadic and familial multiple sclerosis

Brian G. Weinshenker; Dennis E. Bulman; W. Carriere; J. Baskerville; George C. Ebers

We compared demographic and clinical features, including outcome defined by a failure time analysis of disability, in 143 patients with a family history of multiple sclerosis (familial MS) compared with 956 patients without such a history (sporadic MS). Patients with familial MS did not differ from those with sporadic MS even when patients with 1st-degree relatives or multiple relatives with MS were considered separately. An intraclass correlation analysis of 13 pairs of affected 1st-degree relatives, both members of which were followed in our clinic, failed to reveal heterogeneity among different families. We were unable to find any support for differences between familial and sporadic MS.


The Journal of Allergy and Clinical Immunology | 1997

Comparison of the antiasthmatic, oropharyngeal, and systemic glucocorticoid effects of budesonide administered through a pressurized aerosol plus spacer or the Turbuhaler dry powder inhaler

John H. Toogood; Frederick A. White; J. Baskerville; Lawrence J. Fraher; Barbara Jennings

To determine therapeutically and systemically equivalent dosages of budesonide inhaled through the Turbuhaler dry powder inhalation device (Astra Pharma Production AB, Södertälje, Sweden) or pressurized metered-dose inhaler (pMDI) plus Nebuhaler spacer (Astra Pharma Production AB), we compared these devices in a randomized, open, parallel-group trial. Adults with moderate to severe asthma inhaled budesonide (0.4, 0.8, 1.6, and 2.4 mg/day), for 2 weeks at each dose level, through the Turbuhaler (n = 30) or pMDI + Nebuhaler (n = 28). Dose-dependent effects were demonstrated on asthma symptoms (p = 0.0001), daily peak expiratory flow (p = 0.02), blood eosinophils (p = 0.0001), urinary cortisol output per day (p = 0.0001), serum cortisol (p = 0.006), serum osteocalcin (p = 0.0001), and the oropharyngeal Candida colony count (p = 0.0007. analysis of covariance). The ratio of the responses to the two inhalation devices approximated 1.0 for each index measured; that is, no significant between-device difference was found (p > or = 0.29). However, the 95% confidence limits for the ratio of their respective systemic effects on osteocalcin production were 0.83 to 1.48. Thus in adults who use inhalation devices efficiently and have optimally controlled asthma, conversions from the pMDI + Nebuhaler to the Turbuhaler may reasonably be made at milligram equivalent doses of budesonide, then down-titrated to minimize possible systemic effects. Because earlier studies have shown that the Turbuhaler can double intrapulmonary drug delivery in comparison with a pMDI without a spacer, a 50% dose reduction may be indicated when converting from a pMDI to the Turbuhaler.


Preventive Medicine | 1982

Multivariate statistical models for predicting change in smoking behavior following physician advice to quit smoking

Linda L. Pederson; J. Baskerville; James M. Wanklin

Abstract Results of studies relating characteristics of compliance with physician advice to quit smoking among patients with pulmonary disease have been inconclusive. Only two studies have used multivariate statistical procedures; however, these studies were retrospective and included a limited number of predictor variables. A prospective study of 308 newly diagnosed respiratory patients was carried out. Variables measured included diagnosis, physician prediction, sociodemographic characteristics, health beliefs, smoking history, patient prediction, and a preventive health score. Multivariate predictive models were developed for four dichotomous dependent variables: (a) cessation versus continuation of smoking, (b) reduction in amount smoked versus no reduction, (c) successful cessation versus recidivism, and (d) unsuccessful quitting attempts versus no attempt to quit. Accuracy of classification was highest for model (a) and lowest for model (d). Theoretical and practical implications of multivariate prediction are discussed.


Social Science & Medicine | 1984

The role of health beliefs in compliance with physician advice to quit smoking

Linda L. Pederson; James M. Wanklin; J. Baskerville

The Health Belief Model has been proposed to account for patient compliance with therapeutic regimens. The purpose of the present study was to evaluate the utility of this theoretical formulation in accounting for compliance with physician advice to quit smoking among patients with pulmonary disease. Three hypotheses were examined: (1) probability of cessation of smoking is positively related to strength of Health Beliefs; (2) Health Beliefs can be used to explain relationships observed between other variables and compliance; (3) reason for smoking accounts for discrepancies between Health Beliefs and compliance. Results from a prospective study of 308 patients supported hypothesis 3, partially supported hypothesis 1, and did not support hypothesis 2. It was concluded that this conceptual formulation is useful in this context, but that explanations based on arousal level may be more appropriate.

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John H. Toogood

University of Western Ontario

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Barbara Jennings

University of Western Ontario

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G. P. A. Rice

University of Western Ontario

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Neville M. Lefcoe

University of Western Ontario

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Lawrence J. Fraher

University of Western Ontario

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W. Carriere

University of Western Ontario

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Anthony B. Hodsman

University of Western Ontario

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Linda L. Pederson

University of Western Ontario

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