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Biomedical subjects

F E Simons

Publications and source records attributed to F E Simons.

At least 91 records · Page 5Linked to original sources
PubMed1994

Binding properties of protein A and protein G for human IgE.

We studied the binding of protein A and protein G to human monoclonal and polyclonal IgE. An ELISA was used to measure human IgE. Protein A-Sepharose did not bind to monoclonal IgE, but bound to 12-14% of serum polyclonal IgE and to -3% of the polyclonal IgE purified from the serum. No difference in binding to protein A was found between IgE from an allergic patient and that from a non-allergic subject. Protein G bound to neither polyclonal IgE nor monoclonal IgE. Thus, protein G is better than protein A with respect to separation of IgE from IgG.

Humans↗
PubMed1994

Effect of nebulized ipratropium bromide on intraocular pressures in children.

STUDY OBJECTIVE: To evaluate the effects of nebulized ipratropium bromide on intraocular pressures and pupillary responses in children with asthma. DESIGN: A double-blind, randomized, crossover study. SETTING: Children's Hospital of Winnipeg, University of Manitoba. PATIENTS OR PARTICIPANTS: Age 6 to 17 years with asthma. INTERVENTION: Nebulized ipratropium bromide added to albuterol sulfate, albuterol alone, or saline solution was given by face mask and nebulizer. Before and 0.5 h after nebulization, intraocular pressures (mm Hg), pupillary size (mm), and pupillary responses were measured. In a subsequent open study, patients who had been admitted to hospital with acute asthma who were treated with nebulized ipratropium bromide were recruited for measurement of intraocular pressures, pupillary size, and pupillary responses. MEASUREMENTS AND RESULTS: Twenty patients completed the double-blind study, and 26 patients completed the open study. There were no changes in intraocular pressures, pupillary size, or pupillary response after any treatment on any study day in either the double-blind or the open studies. CONCLUSION: In children with asthma, who have no pre-existing ocular abnormalities, the risk of an adverse reaction to nebulized ipratropium bromide delivered by face mask inadvertently absorbed in the eye is extremely small.

Adolescent↗
PubMed1994

H1-receptor antagonists. Comparative tolerability and safety.

First-generation histamine H1-receptor antagonists, such as diphenhydramine, triprolidine, hydroxyzine or chlorpheniramine (chlorphenamine), frequently cause somnolence or other CNS adverse effects. Second-generation H1-antagonists, such as terfenadine, astemizole, loratadine and cetirizine, represent a true advance in therapeutics. In manufacturers' recommended doses, they have a more favourable benefit/risk ratio than their predecessors with regard to lack of CNS effects, and do not exacerbate the adverse CNS effects of alcohol or other CNS-active chemicals. Rarely, some of the newer H1-antagonists may cause cardiac dysrhythmias after overdose or under other specific conditions. The concept of a risk-free H1-antagonist is proving to be an oversimplification. An H1-antagonist absolutely free from adverse effects under all circumstances is not yet available for use. The magnitude of the beneficial effects of each H1-antagonist should be related to the magnitude of the unwanted effects, especially in the CNS and cardiovascular system, and a benefit-risk ratio or therapeutic index should be developed for each medication in this class.

Abnormalities, Drug-Induced↗
PubMed1993

Absence of posterior subcapsular cataracts in young patients treated with inhaled glucocorticoids.

The prevalence of posterior subcapsular cataracts in young patients receiving inhaled glucocorticoids for treatment of chronic asthma is unknown. In a cross-sectional study, slit-lamp examinations were done on 95 consecutive young patients who were taking inhaled beclomethasone or budesonide. No posterior subcapsular cataracts were found. The median age of the patients was 13.8 (range 5.8-24.8). The median dose of inhaled beclomethasone or budesonide was 750 micrograms/day (range 300-2000), or 12.9 micrograms/kg per day (range 7.5-34.2). The median duration of treatment was 5 years (range 1-15). 77% of the patients had not used oral glucocorticoids in the year preceding the examination. This study suggests that routine screening for posterior subcapsular cataracts in this patient population is not warranted.

Administration, Inhalation↗
PubMed1993

Cetirizine pharmacokinetics and pharmacodynamics in primary biliary cirrhosis.

The new H1-receptor antagonist, cetirizine, is eliminated primarily unchanged by renal excretion and is thus potentially useful for relief of pruritus in patients with hepatic dysfunction, in whom many H1-receptor antagonists are contraindicated. The authors studied the elimination of cetirizine in six patients with primary biliary cirrhosis. In contrast to data obtained in healthy adults with normal hepatic function reported in the medical literature, they found that the mean serum elimination half-life value of cetirizine, 13.8 +/- 1.8 hours, was longer, and the mean clearance rate, 0.44 +/- 0.10 mL/min/kg, was lower (P < .05). The mean peak serum cetirizine concentration, 498 +/- 118 ng/mL, was higher, the mean area under the curve, 6438 +/- 1621 ng/mL/hr, was larger, and the mean fraction of the dose excreted as unchanged cetirizine in the urine, .32 +/- .14, was lower (P < .05). The duration of action of cetirizine was prolonged, as evidenced by significant suppression of the histamine-induced wheal and flare for 48 and 72 hours, respectively, after a single dose. Cetirizine elimination was impaired in patients with hepatic dysfunction.

Aged↗
PubMed1993

Treatment of allergic rhinitis with intranasal corticosteroids in patients with mild asthma: effect on lower airway responsiveness.

The effect of treatment of allergic rhinitis with intranasal corticosteroids on lower airway responsiveness was assessed in a randomized, double-blind, placebo-controlled, crossover study. Twenty-one young patients with perennial allergic rhinitis and asthma, with documented lower airway hyperresponsiveness (PC20 methacholine < 8 mg/ml), were treated with intranasal aqueous beclomethasone dipropionate and placebo, each given for 4 weeks. Patients recorded rhinitis and asthma symptom scores and monitored peak expiratory flow rates every morning and evening. Patients recorded global assessment of rhinitis and global asthma symptom scores at the beginning and end of each treatment. PC20 methacholine was performed at baseline and at the end of each treatment period. Intranasal beclomethasone dipropionate significantly reduced global rhinitis symptom scores (p = 0.05) after 4 weeks of treatment. Global asthma scores did not change significantly (p = 0.2). Geometric mean PC20 methacholine improved significantly after 4 weeks of intranasal beclomethasone, but not after placebo (p = 0.04). Daily morning and evening rhinitis symptom scores were lower in patients treated with intranasal corticosteroids over the first 4 weeks of treatment, but carryover effect of steroids precluded comparative analysis of the second 4-week block (morning p = 0.06, evening p = 0.03). Morning asthma scores tended to decrease (p = 0.07). Evening asthma scores were significantly decreased at weeks 2 and 3 (p = 0.001, p = 0.02, respectively). No change in peak expiratory flow rate was seen. This study confirms that treatment of inflammation in the upper airways indirectly improves asthma symptoms and decreases bronchial hyperreactivity. Ignoring inflammation in the upper airway may lead to suboptimal results in asthma treatment.

Administration, Intranasal↗
PubMed1993

Binding of dog immunoglobulins G, A, M, and E to concanavalin A.

The binding of dog immunoglobulins G, A, M and E to concanavalin A (Con A) has been investigated. A passive cutaneous anaphylaxis test was used for measurement of dog IgE, and enzyme-linked immunosorbent assay was used for measurement of dog IgG, IgA and IgM. After the dog serum fraction was applied to a Con A-Sepharose column, sequential elution with different buffers was performed; 100% of IgE and IgM, 60% of IgG and 58% of IgA bound to the Con A-Sepharose. IgE was eluted by mannose, methylglucose, and methylmannoside. IgG was eluted by glucose, mannose, methylglucose, and methylmannoside. IgA and IgM were eluted by methylmannoside only. This provides a useful technique in the purification of dog immunoglobulins, especially dog IgE.

Animals↗
PubMed1993

Pharmacokinetics and pharmacodynamics of ebastine in children.

Ebastine is a new piperidine-containing, relatively nonsedating second-generation H1-receptor antagonist. In a double-blind, parallel-group study of a single 5 mg or 10 mg dose of ebastine syrup used to treat allergic rhinitis in 20 children aged 6 to 12 years, we tested the hypothesis that the medication would have a duration of action of at least 24 hours. We measured plasma concentrations of carebastine, the pharmacologically active metabolite of ebastine, and the wheals and flares produced by epicutaneous tests with histamine phosphate, 1.0 mg/ml. Ebastine was absorbed well; peak carebastine concentrations occurred approximately 3 hours after dosing. Mean plasma elimination half-life values of carebastine ranged from 10 to 14 hours. The pharmacokinetics of carebastine were linear and dose independent in the dosage range studied. After the 5 or 10 mg dose, there were no significant differences between mean plasma elimination half-life values, mean oral clearance values, or mean apparent volumes of distribution. Mean peak plasma carebastine concentrations and mean areas under the plasma carebastine concentration-time curve after the 10 mg dose were 1.93 and 1.76 times, respectively, the values obtained after the 5 mg dose. Both doses significantly reduced the histamine-induced wheal-and-flare areas for up to 28 hours compared with predose values. The differences in effect between the doses generally were not statistically or clinically significant. No adverse effects were noted. We conclude that ebastine, an effective H1-receptor antagonist with a prompt onset of action and a long duration of action, is suitable for once-daily administration to children.

Butyrophenones↗
PubMed1993

Purification and identification of polyclonal IgE antibodies from ragweed-sensitized dog sera.

We have purified and characterized polyclonal dog IgE. Serum IgE was precipitated by (NH4)2SO4 and then purified by two different procedures. Ion exchange on DEAE-Sephacel, followed by HPLC using Tonen hydroxylapatite and then Protein G-Sepharose, produced a highly purified IgE fraction (No. 1) free of IgG, IgA and IgM as measured by ELISA, but recovery of IgE as measured by passive cutaneous anaphylaxis was low. Gel filtration on Sephacryl S-300, Con A-Sepharose and Protein G-Sepharose recovered 18% of initial IgE, 0.02% IgG, 0.4% IgM and 0.3% IgA. This IgE fraction (No. 2) was used to induce antibody production in rabbits. Western blot analysis was then performed for dog IgE fractions No. 1 and 2. Using the rabbit anti-dog IgE, a prominent IgE band with an apparent molecular mass of 226 kD was identified in fractions No. 1 and 2 subjected to nonreducing SDS-PAGE. This band also reacted with anti-human IgE, but not with anti-dog IgG or anti-dog IgA. Under reducing conditions the approximate molecular mass for the IgE & chain, estimated by Western blot using rabbit anti-dog IgE, was 73 kD, providing a molecular mass of 196 kD for dog IgE.

Allergens↗
PubMed1993

H1-receptor antagonists: does a dose-response relationship exist?

Objective dose-response studies of histamine receptor blockade in the skin have been performed using suppression of the histamine-induced wheal and flare. Results with second-generation H1-antagonists indicate a dose-dependent increase in histamine skin test suppression. Few dose-response studies of H1-antagonists in allergic rhinitis or chronic urticaria have been published. The manufacturers' recommend doses for H1-antagonists appear to be optimal with regard to safety and should not be exceeded, as the incidence of adverse effects may increase when higher doses are used. Also, even if higher doses are given, complete symptom relief may not occur in all patients, as total H1-blockade still leaves the effects of other chemical mediators of inflammation unopposed.

Asthma↗
PubMed1993

Evolution of H1-receptor antagonist treatment.

The introduction of relatively nonsedating H1-receptor antagonists ushered in a new era in the symptomatic treatment of allergic disorders. Unlike first-generation H1-receptor antagonists, the second-generation compounds (such as astemizole, cetirizine, loratadine, and terfenadine) do not cross the blood-brain barrier readily and are thus comparatively free of central nervous system effects. The pharmacokinetic and pharmacodynamic profiles vary considerably by agent, but most of the second-generation drugs are suitable for once-daily dosing. Efficacy of the H1 antagonists is maintained during chronic therapy. The second-generation H1-receptor antagonists are appropriate for use as first-line treatment of allergic rhinoconjunctivitis and urticaria. These agents also have a modest, direct beneficial effect in patients with chronic asthma. The role of the newer H1-receptor antagonists in the treatment of atopic dermatitis, upper respiratory tract infections, and otitis media remains undefined. Recently, the gene encoding the histamine H1 receptor was cloned from bovine adrenal medullae. Emerging evidence suggests that more than one subtype of H1 receptor may exist. It is hoped these advances will pave the way for further improvements in H1-antagonist therapy.

Adult↗
PubMed1993

Measurement of ragweed-specific IgE in canine serum by use of enzyme-linked immunosorbent assays, containing polyclonal and monoclonal antibodies.

Using polyclonal rabbit and monoclonal mouse anti-dog IgE antibodies, we developed ELISA for measurement of ragweed-specific IgE in canine serum. In the ELISA, microtitration plates were coated with ragweed extract and sequentially incubated with canine serum, purified monoclonal or polyclonal anti-dog IgE, and conjugated goat antibody to mouse IgG or rabbit IgG. Serum ragweed-specific IgE values were measured by the 2 ELISA in serum samples from 60 ragweed-allergic dogs and in serum from 10 control dogs. Passive cutaneous anaphylaxis (PCA) tests were performed on these sera to compare results with those of the ELISA. Mean coefficient of variation between assays was 0.20 +/- 0.10 for the assay using the polyclonal antibody and was 0.17 +/- 0.10 for that using monoclonal antibody. Sensitivity was 0.6 U/ml for the ELISA, using polyclonal antibody, and 2.5 U/ml for the ELISA, using monoclonal antibody. Serum ragweed-specific IgE values measured by the 2 ELISA strongly correlated with PCA titers (P < 0.0000), but the ELISA using polyclonal antibody had higher correlation with PCA titer (r = 0.84) than the ELISA using monoclonal antibody (r = 0.59). The geometric mean ragweed-specific IgE value measured by the 2 ELISA and by PCA testing, was significantly higher (P < 0.0000). in allergic dogs than in control dogs. The 2 ELISA were specific, sensitive, and reproducible for measurement of ragweed-specific IgE in canine serum.

Allergens↗
PubMed1992

Bronchodilator and bronchoprotective effects of salmeterol in young patients with asthma.

BACKGROUND: In adults with asthma, the selective beta 2-adrenergic agonist salmeterol has a prolonged bronchodilator and bronchoprotective effect. To date, there are few published studies of salmeterol in children. METHODS: We compared the bronchodilator and bronchoprotective effects of salmeterol, 25 and 50 micrograms, with salbutamol, 200 micrograms, and with placebo, administered via metered-dose inhaler, in a randomized, double-blind, within-patient, four-way crossover, single-dose study in 20 children. RESULTS: Mean baseline forced expiratory volume in 1 second (FEV1) and PC20 methacholine were not significantly different (p > 0.05) on the 4 study days, and did not change significantly after placebo. FEV1 increased significantly from 5 to 30 minutes after salbutamol, and from 5 minutes to 12 hours after 25 micrograms or 50 micrograms salmeterol, compared with placebo. After 25 micrograms or 50 micrograms salmeterol, FEV1 was significantly lower than after salbutamol at 5 and 10 minutes, did not differ from salbutamol at 30 minutes, and was significantly greater than after salbutamol from 3 to 12 hours. No significant difference occurred between the effect of 25 micrograms salmeterol and the effect of 50 micrograms salmeterol on FEV1. After salbutamol, there was a significant increase in PC20 only at 30 minutes. After 25 micrograms or 50 micrograms salmeterol, PC20 increased significantly from 30 minutes to 12 hours. Salmeterol, 25 micrograms and 50 micrograms provided significantly greater bronchoprotection than salbutamol from 3 to 12 hours and from 30 minutes to 12 hours, respectively. Salmeterol, 50 micrograms, provided significantly better bronchoprotection than 25 micrograms salmeterol from 30 minutes to 12 hours. The amount of change in PC20 accounted for by change in FEV1 varied from 14% to 28%, indicating that protection against bronchoconstriction was not entirely dependent on bronchodilation. CONCLUSIONS: Salmeterol is a potent, long-acting bronchodilator, with a slower onset of bronchodilation than salbutamol. It provides significantly greater and longer-lasting protection against bronchoconstriction than salbutamol.

Adrenergic beta-Agonists↗
PubMed1992

The antiallergic effects of antihistamines (H1-receptor antagonists).

Most first-generation and second-generation H1-receptor antagonists have readily demonstrable antiallergic effects in vitro, although high concentrations of some of the medications are required to inhibit mediator secretion from mast cells or basophils. These antiallergic effects can also be seen in vivo in skin, nasal, lung, and ocular challenge studies. Some H1-receptor antagonists appear to have an antiallergic effect in one organ but not in another. In many in vivo studies, doses of H1-receptor antagonists three or more times higher than those required for H1 blockade must be given to achieve the antiallergic effect. It would be premature to attempt to reclassify the H1 antagonists according to their antiallergic properties because these properties have not been investigated fully and their relative contribution to the overall therapeutic effectiveness of each H1 receptor antagonist is unknown.

Basophils↗