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Biomedical subjects

S Findlay

Publications and source records attributed to S Findlay.

At least 19 recordsLinked to original sources
PubMed1999

Influence of Three Contrasting Detrital Carbon Sources on Planktonic Bacterial Metabolism in a Mesotrophic Lake.

Abstract Lakes receive organic carbon from a diversity of sources which vary in their contribution to planktonic microbial food webs. We conducted a mesocosm study to test the effects of three different detrital carbon sources (algae, aquatic macrophytes, terrestrial leaves) on several measures of microbial metabolism in a small meso-eutrophic lake (DOC approximately 5 mg/L). Small DOC additions (DeltaC < 1 mg/L) affected bacterial numbers, growth, and pathways of carbon acquisition. Macrophyte and leaf detritus significantly increased TDP and color, but bacterial densities initially (+12 h) were unaffected. After 168 h, densities in systems amended with terrestrial detritus were 60% less than in controls, while production rates in mesocosms with macrophyte detritus were 4-fold greater. Detritus treatments resulted in greater per-cell production rates either through stable cell numbers and greater growth rates (macrophyte-C) or lower densities with stable production rates (terrestrial-C). After only 12 h, rates of leucine aminopeptidase (LAPase) activity were 2.5x greater in macrophyte-C systems than in controls, but LAPase and beta-N-acetylglucosamindase activities in systems amended with terrestrial-C were only 50% of rates in controls. After 168 h, beta-xylosidase rates were significantly greater in communities with terrestrial and phytoplankton detritus. Microbial utilization of >20% of 102 carbon sources tested were affected by at least one detritus addition. Macrophyte-C had positive (6% of substrates) and negative (14%) effects on substrate use; terrestrial detritus had mainly positive effects. An ordination based on carbon-use profiles (+12 h) revealed a cluster of macrophyte-amended communities with greater use of psicose, lactulose, and succinamic acid; controls and algal-detritus systems were more effective in metabolizing two common sugars and cellobiose. After 168 h, communities receiving terrestrial detritus were most tightly clustered, exhibiting greater use of raffinose, pyroglutamic acid, and sebacic acid. Results suggest that pelagic bacterial communities respond to changes in organic carbon source rapidly and by different routes, including shifts in per-cell production rates and variations in degradation of a variety of compounds comprising the DOC pool.

Journal Article↗
PubMed1998

Effects of budesonide by means of the Turbuhaler on the hypothalmic-pituitary-adrenal axis in asthmatic subjects: a dose-response study.

BACKGROUND: As a general phenomenon, corticosteroids may suppress the activity in the hypothalamic-pituitary-adrenal (HPA) axis. The adrenal stimulation test is a commonly used method to assess the relative risk of exogenous corticosteroids to induce systemic side effects. OBJECTIVES: This clinical trial was performed to assess the effects of budesonide on the HPA axis (at 800, 1600, or 3200 microg/day, given as a twice daily regimen, administered by means of the Turbuhaler) in adult patients with mild, non-steroid-dependent asthma. METHODS: Sixty-four asthmatic patients received budesonide or placebo by inhalation or 10 mg/day oral prednisone once daily as a positive control in a double-blind, double-dummy, randomized, placebo-controlled, parallel-group, multicenter study. Plasma cortisol concentration was measured to assess the effect on the HPA axis before and during a 6-hour infusion of synthetic adrenocorticotropic hormone (ACTH), cosyntropin. RESULTS: After 6 weeks of treatment, plasma cortisol concentrations after adrenal stimulation by cosyntropin infusion had fallen by 4% in the placebo group; by 13%, 11%, and 27% in the budesonide groups (800, 1600, and 3200 microg/day, respectively); and by 35% in the prednisone group. The decrease was significant only in the 3200 microg/day budesonide (p = 0.03) and prednisone (p = 0.005) groups. Over the same time period, decreases in basal plasma cortisol concentrations were 1% in the placebo group; 19%, 19%, and 34% in the three budesonide groups; and 37% in the prednisone group. Only in the prednisone group was the decrease significant (p = 0.03 vs placebo). CONCLUSIONS: In this study budesonide inhaled by means of the Turbuhaler, at doses recommended for clinical use (800 or 1600 microg/day), did not produce any statistically significant suppression of the HPA axis compared with placebo.

Administration, Inhalation↗
PubMed1996

Comparison of efficacy, safety, and skin test inhibition of cetirizine and astemizole.

BACKGROUND: Astemizole, an H1-histamine-receptor antagonist prescribed for seasonal allergic rhinitis, has a slow onset of action and a strong suppressive effect on the wheal and flare reaction, which interferes with skin testing results. The newer antihistamine cetirizine appears to have a rapid onset of action and a low potential to interfere with posttreatment skin testing results. OBJECTIVE: To compare the efficacy, safety, and skin test inhibition of astemizole and cetirizine in the treatment of seasonal allergic rhinitis. METHODS: In a double-blind, parallel-group study conducted at six sites during ragweed pollination season, 263 subjects were randomized to receive 10 mg of astemizole, 5 mg of cetirizine, or 10 mg of cetirizine daily for 2 weeks. The subjects rated seven allergic rhinitis symptoms daily, the subjects and investigators provided global assessments of the responses to the treatments, and the subjects rated their satisfaction with the treatments. Thirty-nine subjects at one study site underwent quantitative skin testing before and after treatment. RESULTS: As measured by reduction from baseline in total symptom severity score, which was the primary efficacy measure in the study, all three treatments significantly relieved the symptoms of allergic rhinitis (P less than .05). This finding was supported by the global ratings and the subject satisfaction ratings. There were no significant differences among the three treatments for reduction from baseline in total symptom severity score. The mean subject satisfaction score with 10 mg of cetirizine was significantly greater than that with astemizole (P less than .05). In the skin tests performed 3, 7, and 14 days after the end of antihistamine treatment, the subjects who had received the cetirizine doses had significantly greater mean sum of wheal and mean sum of erythema values than those who had received the astemizole dose (P less than .05). Sensitivity to ragweed pollen extract returned to 90% of baseline within three days of the end of cetirizine treatment. Both drugs were well tolerated and their adverse event profiles were similar. CONCLUSIONS: Astemizole and cetirizine are effective and well tolerated in alleviating the symptoms of ragweed-induced allergic rhinitis. Cetirizine inhibits skin test results to a much lesser extent than does astemizole. Physicians may wish to consider the potential for skin test inhibition when selecting an antihistamine for patients with allergic rhinitis.

Adolescent↗
PubMed1995

Comparative efficacy and safety of a once-daily loratadine-pseudoephedrine combination versus its components alone and placebo in the management of seasonal allergic rhinitis.

BACKGROUND: The treatment of symptoms of seasonal allergic rhinitis often requires the use of a decongestant to improve nasal congestion, along with an antihistamine to adequately control other nasal, as well as nonnasal symptoms. METHODS: In this double-blind, placebo-controlled, multicenter study, 874 patients with moderate to severe symptoms of seasonal allergic rhinitis were treated with one of the following: SCH 434 QD (a combination of 10 mg of loratadine in the coating and 240 mg of pseudoephedrine sulfate in an extended-release core) once daily, 10 mg of loratadine once daily, 120 mg of pseudoephedrine sulfate every 12 hours, or placebo for 2 weeks. RESULTS: SCH 434 QD was consistently superior to placebo in controlling the symptoms of seasonal allergic rhinitis. Composite symptom scores (total, total nasal, and total nonnasal) were reduced significantly in patients treated with SCH 434 QD as compared with placebo (p < 0.01). When compared with its individual components, reductions in mean symptom scores were consistently greater, numerically, in patients treated with SCH 434 QD than in patients who were treated with either loratadine or pseudoephedrine alone. SCH 434 QD was superior to pseudoephedrine in reducing nonnasal symptoms at all time points (p < 0.01), and superior to loratadine in relieving nasal stuffiness at end point (p < 0.01). In the physicians' evaluation of therapeutic response, the SCH 434 QD group had the greatest number of patients with a good or excellent response at end point (58%). All treatments were generally well tolerated with no serious or unusual adverse events. Insomnia and nervousness, adverse events commonly associated with pseudoephedrine, were noted in a significantly greater number of patients treated with SCH 434 QD or pseudoephedrine (p < or = 0.04) as compared with those treated with loratadine or placebo. CONCLUSIONS: The results of the study demonstrate that SCH 434 QD is more effective than placebo or either of its components alone in the treatment of seasonal allergic rhinitis.

Adolescent↗