Analysis of Citrus Bioflavonoid Content and Dipeptidyl Peptidase-4 Inhibitory Potential of Commercially Available Supplements

Citrus bioflavonoids are polyphenolic plant-derived pigments found in high levels in oranges, lemons, grapefruits and other citrus fruits. The three most abundant types of citrus bioflavonoids are hesperidin, naringenin and eriocitrin. Citrus bioflavonoids have long been known to possess powerful free radical-scavenging properties and cardioprotective effects. The study involved the analysis of 10 commercially available citrus bioflavonoid supplements from three different countries: Australia, the United States and Canada. The supplements were tested for their citrus bioflavonoid content which varied from 0.8 to 33.3% w/w. The daily bioflavonoid dose varied from 19 mg to 560 mg. Hesperidin was the major citrus bioflavonoid in nine out of ten supplements. One supplement was found to contain less than 10% of the quantity of rutin claimed to have been added. The DPP-4 inhibitory potential, compared through an estimation of rutin equivalence, ranged from 1.9 mg to 400 mg per day. This data highlights the variability between the supplements in their potential to inhibit DPP-4 for subsequent health benefits.

Pharmacokinetic and pharmacodynamic effects of 2 registered omeprazole preparations and varying dose rates in horses

Background

Omeprazole preparations vary in bioavailability in horses.

Hypothesis/Objectives

To characterize the pharmacokinetics and pharmacodynamics of an existing enteric‐coated oral omeprazole paste (REF) and a novel, in‐feed, enteric‐coated dry granule preparation (NOV).

Animals

Twelve Standardbred/Thoroughbred mares free from clinical disease.

Methods

A prospective, blinded randomized interventional study was trial, conducted in 3 parts: (a) bioavailability study, (b) dose titration study, and (c) comparative clinical pharmacodynamic study, each using a blocked crossover design.

Results

Consistent with the larger dose administered, Cmax (median, 1032 ng/mL; range, 576‐1766) and AUC0‐24 (median, 63.9 μg/mL*min; range, 42.4‐152.4) were greater after single oral administration of NOV than REF (282.7 ng/mL; range, 94.8‐390.2, and 319 23.8 μg/mL*min; range, 8.2‐42.3, respectively; both P = .004). No differences were observed between products for absolute oral bioavailability (NOV 55% range, 15‐88; REF 17% range, 10‐77; P = .25). Treatment with both preparations was associated with reduced gastric squamous ulcer scores and increased pH of gastric fluid. Bioequivalence was demonstrated for pharmacodynamic measures with the exception of % time pH <4, despite differences in dose rate and subsequent plasma omeprazole concentrations.

Conclusions and Clinical Importance

The findings of this study indicate that the NOV product would be a suitable alternative to the reference product, and confirm that plasma concentrations of omeprazole and omeprazole dose do not predict drug pharmacodynamics in horses.

Phytosterol supplements do not inhibit dipeptidyl peptidase-4

BACKGROUND AND AIMS

Several commercially available phytosterol supplements are promoted for their cholesterol-lowering effects. However, limited information is available about their potential anti-hyperglycaemic effects. This study aimed to evaluate the dipeptidyl peptidase-4 (DPP-4) inhibitory effects of phytosterol supplements in silico and in vitro to determine their potential for anti-diabetic activity.

METHODS

Docking studies were carried out in silico to evaluate the potential for interactions between three major phytosterol compounds (stigmasterol, β-sitosterol, campesterol) and the DPP-4 enzyme, the enzyme that is inhibited by the anti-diabetic gliptins. Gas chromatography-tandem mass spectrometry (GC-MS/MS) was used to analyse three different supplements for phytosterol content. DPP-4 inhibitory activity was tested in vitro for these phytosterol supplements and two major phytosterol standards.

RESULTS

In silico calculations predicted free binding energies for DPP-4 with the phytosterols to be: stigmasterol -8.78 kcal/mol; β-sitosterol -8.70 kcal/mol; campesterol -8.40 kcal/mol. These binding energies indicated a potential for significant DPP-4 inhibition. However, these results were not supported by the in vitro studies. Stigmasterol and β-sitosterol had an IC₅₀ > 50 mg/ml (maximum tested concentration) and the Thompson's Cholesterol Manager® and Mega Strength Beta Sitosterol® supplements gave an IC₅₀ > 100 mg/ml (maximum tested concentration). Blackmores Cholesterol Health® gave an IC₅₀ value of 40 mg/ml which was attributed to β-carotene content.

CONCLUSIONS

Phytosterol supplements do not appear to offer any anti-diabetic activity potential via pathways that involve the inhibition of DPP-4.

The salmeterol anomaly and the need for a urine threshold

Salmeterol is a long acting beta2-agonist (LABA) used widely for the treatment of airways disease. There is evidence that beta2-agonists, including salmeterol, have the potential for performance enhancing effects when delivered at supratherapeutic doses. For this reason, all beta2-agonists are currently on the Prohibited List issued by the World Anti-Doping Agency (WADA), regardless of dosing route with some exemptions for inhaled salbutamol, formoterol, and salmeterol when used at therapeutic inhaled doses. For 2020, salmeterol use is permitted up to a therapeutic dosing threshold of 200 μg daily, but unlike salbutamol and formoterol, there is an anomaly; currently there is no urine threshold to control for supratherapeutic dosing beyond this dosing threshold. Salmeterol, however, is reportable as an adverse analytical finding (AAF) at levels above 10 ng/mL. Complicating matters is that following inhalation, salmeterol parent drug is present at relatively low levels compared with other beta2-agonists due to rapid metabolism to the metabolite, alpha-hydroxysalmeterol, which is typically present at higher levels than the parent drug. Moreover, peak parent drug levels following permitted therapeutic dosing are below the minimum required performance level (MRPL) of 10 ng/mL for salmeterol (50% of the MRPL that analytical laboratories are required to meet for non-threshold beta2-agonists), hence the presence of salmeterol may be unreported. For consistency, a urine threshold should be introduced for salmeterol as a matter of priority, to balance the needs of athletes who use salmeterol therapeutically up to the agreed dosing threshold, with the need to control supratherapeutic dosing for doping intentions and athlete harm minimization.

Beta2 -adrenergic agonist clenbuterol increases energy expenditure and fat oxidation, and induces mTOR phosphorylation in skeletal muscle of young healthy men

Clenbuterol is a beta₂ -adrenoceptor agonist marketed as an asthma reliever but is not approved for human use in most countries due to concerns of adverse cardiac effects. Given its demonstrated hypertrophic and lipolytic actions in rodents, clenbuterol is one of the most widely abused doping substances amongt athletes and recreational body-builders seeking leanness. Herein, we examined the effect of clenbuterol ingestion on metabolic rate as well as skeletal muscle mammalian target of rapamycin (mTOR) phosphorylation and protein kinase A (PKA)-signaling in six young men. Before and 140 min after ingestion of 80 μg clenbuterol, resting metabolic rate and contractile function of the quadriceps muscle were measured, and blood samples as well as vastus lateralis muscle biopsies were collected. Clenbuterol increased resting energy expenditure by 21% (P < 0.001), and fat oxidation by 39% (P = 0.006), whereas carbohydrate oxidation was unchanged. Phosphorylation of mTOR^Ser2448 and PKA substrates increased by 121% (P = 0.004) and 35% (P = 0.006), respectively, with clenbuterol. Maximal voluntary contraction torque decreased by 4% (P = 0.026) and the half-relaxation time shortened by 9% (P = 0.046), while voluntary activation, time to peak twitch, and peak twitch torque did not change significantly with clenbuterol. Glycogen content of the vastus lateralis muscle did not change with clenbuterol. Clenbuterol increased circulating levels of glucose (+30%; P < 0.001), lactate (+90%; P = 0.004), insulin (+130%; P = 0.009), and fatty acids (+180%; P = 0.001). Collectively, these findings indicate that clenbuterol is an efficient thermogenic substance that possibly also exerts muscle hypertrophic actions in humans. For these reasons, the restrictions imposed against clenbuterol in competitive sports seem warranted.

Clinical efficacy of bronchodilators in equine asthma: Looking for minimal important difference

BACKGROUND

Airway obstruction is the main trait of severe equine asthma that affects respiratory function and elicits detrimental effects on clinical presentation. Only few and underpowered clinical studies have investigated the impact of improvement in lung function induced by bronchodilators on the clinical signs of asthma-affected horses.

OBJECTIVES

To identify the minimal important difference (MID) in lung function elicited by bronchodilator leading to a meaningful improvement in clinical signs.

STUDY DESIGN

Pairwise meta-analysis and meta-regression analysis.

METHODS

Literature searches were performed for studies that investigated the effect of bronchodilator therapy on lung function and clinical condition of asthmatic horses. The relationship between the change in lung function variables and clinical score was analysed via random-effect meta-regression. One-point change of the Improved clinically Detectable Equine Asthma Scoring System (IDEASS) score was used to identify the MID.

RESULTS

A significant (P<0.05) relationship was found between the changes in IDEASS score and maximum change in transpulmonary pressure (ΔPpl_max ) or pulmonary resistance (R_L ). Since only the model resulting for R_L passed through the origin (Y-intercept when X = 0: -0.31, 95% CI -0.75 to 0.14), this variable was used to identify the MID correlated with a meaningful improvement in clinical signs. The resulting MID value was a change in R_L of 0.63 cm H₂ O/L/s (95% CI 0.33-0.94), representing the slope of meta-regression model (high quality of evidence).

MAIN LIMITATIONS

No long-term studies investigated the effect of bronchodilator agents on both lung function and clinical signs in asthmatic horses.

CONCLUSIONS

In conclusion, bronchodilator pharmacotherapy in equine asthma elicits clinically meaningful effect when R_L increases ≥1 cm H₂ O/L/s, a value indicating the MID. Assessing the MID based on change in R_L may improve the quality of evidence and the scientific impact of future clinical trials as it extends beyond the simple, and limiting, evaluation of statistical significance.

Enantioselective disposition of (R,R)-formoterol, (S,S)-formoterol and their respective glucuronides in urine following single inhaled dosing and application to doping control

Formoterol is a long-acting beta2-adrenoceptor agonist (LABA) used for the treatment of asthma and exercise-induced bronchoconstriction. Formoterol is usually administered as a racemic (rac-) mixture of (R,R)- and (S,S)-enantiomers. While formoterol is restricted by the World Anti-Doping Agency (WADA), inhalation of formoterol is permitted to a predetermined dose (54 μg/24 hours) and a urine threshold of 40 ng/mL. However, chiral switch enantiopure (R,R)-formoterol is available, effectively doubling the therapeutic advantage for the same threshold. The aim of this study was to investigate whether formoterol exhibits enantioselective urinary pharmacokinetics following inhalation. Six healthy volunteers were administered a 12 μg inhaled dose of rac-formoterol. Urine was collected over 24 hours and analyzed by enantioselective ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) assay. Total (free drug plus conjugated metabolite) median (min-max) rac-formoterol urine levels following inhalation were 1.96 (1.05-13.4) ng/mL, 1.67 (0.16-9.67) ng/mL, 0.45 (0.16-1.51) ng/mL, 0.61 (0.33-0.78) ng/mL, and 0.17 (0.08-1.06) ng/mL at 2, 4, 8, 12, and 24 hours, respectively, well below the 2019 urine threshold. The proportion of conjugation differed between enantiomers with glucuronide conjugation much greater for (R,R)-formoterol (around 30%-60% of total) compared to (S,S)-formoterol (0%-30%). There was clear evidence of inter-individual enantioselectivity observed in the ratios of (R,R):(S,S)-formoterol, where (S,S)- was predominant in free formoterol, and (R,R)- predominant in the conjugated metabolite. In conclusion, rac-formoterol delivered by inhalation exhibits enantioselective elimination in urine following single-dose administration. Enantioselective assays should be employed in doping control to screen for banned beta2-agonist chiral switch products such as (R,R)-formoterol, and total hydrolyzed rac-formoterol is warranted to account for inter-individual differences in enantioselective glucuronidation.

Changes in biomarkers of cardiac dysfunction during exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Cardiac dysfunction is associated with a higher mortality in exacerbations of chronic obstructive pulmonary disease (COPD). It is unknown how the heart responds to treatment of COPD exacerbations. We followed cardiac biomarker levels during hospital admissions for exacerbations of COPD and hypothesised that these biochemical markers of cardiac dysfunction might be affected the severity and treatment of exacerbations of COPD.

METHODS

N-terminal pro-B-type natriuretic peptide (NT-proBNP) and troponin T were measured at admission, 12 h, 72 h, and clinical stability in 176 patients. In a second cohort (n = 93), associations between blood salbutamol concentrations and biomarker changes at 12 h were analysed.

RESULTS

NT-proBNP increased from a geometric mean of 43 pmol/L at admission to 56 pmol/L at 12 h (p < 0.001), 53 pmol/L at 72 h (p = 0.045), and decreased to 25 pmol/L (p < 0.001) at stability. Troponin T levels decreased at 12 h (p < 0.001), but 15/174 (9%) patients had a clinically significant rise. Nebulised bronchodilator treatment and blood salbutamol concentrations were associated with greater increases in NT-proBNP rise at 12 h independently of baseline COPD or exacerbation severity and other treatments (p < 0.05). Nebulised bronchodilator and blood salbutamol concentrations also predicted rises in troponin T in univariate analyses (p < 0.05).

CONCLUSIONS

NT-proBNP continues to rise after admission to hospital for COPD exacerbations and a minority of patients have clinically significant rises in cardiac troponins. These rises were associated with nebulised beta₂-agonist treatment. These findings suggest that high doses of beta₂-agonists may exacerbate cardiac dysfunction in COPD.

Long-Acting β2-Agonists in Asthma: Enantioselective Safety Studies are Needed

Long-acting β2-agonists (LABAs) such as formoterol and salmeterol are used for prolonged bronchodilatation in asthma, usually in combination with inhaled corticosteroids (ICSs). Unexplained paradoxical asthma exacerbations and deaths have been associated with LABAs, particularly when used without ICS. LABAs clearly demonstrate effective bronchodilatation and steroid-sparing activity, but long-term treatment can lead to tolerance of their bronchodilator effects. There are also concerns with regard to the effects of LABAs on bronchial hyperresponsiveness (BHR), where long-term use is associated with increased BHR and loss of bronchoprotection. A complicating factor is that formoterol and salmeterol are both chiral compounds, usually administered as 50:50 racemic (rac-) mixtures of two enantiomers. The chiral nature of these compounds has been largely forgotten in the debate regarding LABA safety and effects on BHR, particularly that (S)-enantiomers of β2-agonists may be deleterious to asthma control. LABAs display enantioselective pharmacokinetics and pharmacodynamics. Biological plausibility of the deleterious effects of β2-agonists (S)-enantiomers is provided by in vitro and in vivo studies from the short-acting β2-agonist (SABA) salbutamol. Supportive clinical findings include the fact that patients in emergency departments who demonstrate a blunted response to salbutamol are more likely to benefit from (R)-salbutamol than rac-salbutamol, and resistance to salbutamol appears to be a contributory mechanism in rapid asthma deaths. More effort should therefore be applied to investigating potential enantiospecific effects of LABAs on safety, specifically bronchoprotection. Safety studies directly assessing the effects of LABA (S)-enantiomers on BHR are long overdue.

Beta2 -adrenoceptor agonist salbutamol increases protein turnover rates and alters signalling in skeletal muscle after resistance exercise in young men

KEY POINTS

Animal models have shown that beta₂ -adrenoceptor stimulation increases protein synthesis and attenuates breakdown processes in skeletal muscle. Thus, the beta₂ -adrenoceptor is a potential target in the treatment of disuse-, disease- and age-related muscle atrophy. In the present study, we show that a few days of oral treatment with the commonly prescribed beta₂ -adrenoceptor agonist, salbutamol, increased skeletal muscle protein synthesis and breakdown during the first 5 h after resistance exercise in young men. Salbutamol also counteracted a negative net protein balance in skeletal muscle after resistance exercise. Changes in protein turnover rates induced by salbutamol were associated with protein kinase A-signalling, activation of Akt2 and modulation of mRNA levels of growth-regulating proteins in skeletal muscle. These findings indicate that protein turnover rates can be augmented by beta₂ -adrenoceptor agonist treatment during recovery from resistance exercise in humans.

ABSTRACT

The effect of beta₂ -adrenoceptor stimulation on skeletal muscle protein turnover and intracellular signalling is insufficiently explored in humans, particularly in association with exercise. In a randomized, placebo-controlled, cross-over study investigating 12 trained men, the effects of beta₂ -agonist (6 × 4 mg oral salbutamol) on protein turnover rates, intracellular signalling and mRNA response in skeletal muscle were investigated 0.5-5 h after quadriceps resistance exercise. Each trial was preceded by a 4-day lead-in treatment period. Leg protein turnover rates were assessed by infusion of [¹³ C₆ ]-phenylalanine and sampling of arterial and venous blood, as well as vastus lateralis muscle biopsies 0.5 and 5 h after exercise. Furthermore, myofibrillar fractional synthesis rate, intracellular signalling and mRNA response were measured in muscle biopsies. The mean (95% confidence interval) myofibrillar fractional synthesis rate was higher for salbutamol than placebo [0.079 (95% CI, 0.064 to 0.093) vs. 0.066 (95% CI, 0.056 to 0.075%) × h^-1 ] (P < 0.05). Mean net leg phenylalanine balance 0.5-5 h after exercise was higher for salbutamol than placebo [3.6 (95% CI, 1.0 to 6.2 nmol) × min^-1  × 100 g_{Leg Lean Mass}^-1 ] (P < 0.01). Phosphorylation of Akt2, cAMP response element binding protein and PKA substrate 0.5 and 5 h after exercise, as well as phosphorylation of eEF2 5 h after exercise, was higher (P < 0.05) for salbutamol than placebo. Calpain-1, Forkhead box protein O1, myostatin and Smad3 mRNA content was higher (P < 0.01) for salbutamol than placebo 0.5 h after exercise, as well as Forkhead box protein O1 and myostatin mRNA content 5 h after exercise, whereas ActivinRIIB mRNA content was lower (P < 0.01) for salbutamol 5 h after exercise. These observations suggest that beta₂ -agonist increases protein turnover rates in skeletal muscle after resistance exercise in humans, with concomitant cAMP/PKA and Akt2 signalling, as well as modulation of mRNA response of growth-regulating proteins.

Citrus bioflavonoids dipeptidyl peptidase-4 inhibition compared with gliptin antidiabetic medications

This study compared dipeptidyl peptidase-4 (DPP-4) inhibitory activity of citrus bioflavonoid nutraceuticals compared with three gliptins. Citrus bioflavonoid standards and three commercially available citrus bioflavonoid supplements (Thompson's Super Bioflavonoid Complex^®(SB), Ethical Nutrients Bioflavonoids Plus Vitamin C^®(EN), and Country Life Citrus Bioflavonoids and Rutin^®(CB)) were considered in this study. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis was undertaken to identify and quantitate the citrus bioflavonoids present in each supplement. The DPP-4 inhibitory activity was determined by fluorometric assay. All of the tested individual citrus flavonoids demonstrated DPP-4 inhibitory activity, with IC₅₀ values ranging from 485 μM (rutin) to 5700 μM (hesperitin and eriodictyol). Similarly, the flavonoid supplements had IC₅₀ values of 16.9 mg/mL (EN), 3.44 mg/mL (SB) and 2.72 mg/mL (CB). These values compare with gliptin IC₅₀ values of 0.684 μM (sitagliptin), 0.707 μM (saxagliptin) and 2.286 μM (vildagliptin). The supplement flavonoid content varied from 11.98% (CB) to 5.26% (EN) and 14.51% (SB) of tablet mass, corresponding to daily flavonoid doses of around 300, 150 and 400 mg, respectively, with CB and SB containing rutin at levels of 7.0% and 7.5% of tablet mass, respectively. While our data demonstrated that citrus bioflavonoid based supplements do possess DPP-4 inhibitory activity, they are several orders of magnitude less potent than gliptins. Further studies using higher concentrations of citrus bioflavonoids, as well as investigations into antioxidant properties which may add additional benefit are warranted.

Salmeterol undergoes enantioselective bronchopulmonary distribution with receptor localisation a likely determinant of duration of action

BACKGROUND

Salmeterol (a long acting beta2-agonist) is a chiral molecule. (RR)-salmeterol is responsible for pharmacological effect, but basic knowledge of enantioselective pulmonary pharmacodynamics and pharmacokinetics of salmeterol remains unknown. There are safety concerns with (S)-enantiomers of beta2-agonists, with suggestions that these enantiomers may increase bronchial hyperresponsivneness in asthma patients.

METHODOLOGY

Horses (n = 12) received racemic (rac-) salmeterol 250 μg via inhalation. Enantioselective UPLC-MS/MS was used to determine (R)- and (S)-salmeterol concentrations in pulmonary epithelial lining fluid (PELF) sampled 2, 5, 10 and 15 min after administration, in central lung (endoscopic bronchial biopsy) and peripheral lung (percutaneous pulmonary biopsy) tissues (at 20 and 25 min respectively), and in plasma samples.

RESULTS

Physiologically relevant tissue concentrations were found for both enantiomers, with median levels greater in central than peripheral lung (equivalent to 32 and 5 mM (R)-salmeterol for central and peripheral lung respectively). Levels in PELF decreased around 50% over 15 min and enantioselective distribution was observed in the central lung with levels of (R)-salmeterol around 30% higher than (S)-salmeterol.

CONCLUSION

Salmeterol distribution is enantioselective in the central lung. This suggests duration of action is more likely associated with specific B2ADR localisation effects rather than non-specific physiochemical factors which would not be enantioselective.

Correction to: Beta2-Agonist Doping Control and Optical Isomer Challenges

Page 1789, table 1, 'Carmoterol' row: The cell entry in the 'Stereochemistry' column, which previously read.

Chronic β2 -adrenoceptor agonist treatment alters muscle proteome and functional adaptations induced by high intensity training in young men

KEY POINTS

While several studies have investigated the effects of exercise training in human skeletal muscle and the chronic effect of β₂ -agonist treatment in rodent muscle, their effects on muscle proteome signature with related functional measures in humans are still incompletely understood. Herein we show that daily β₂ -agonist treatment attenuates training-induced enhancements in exercise performance and maximal oxygen consumption, and alters muscle proteome signature and phenotype in trained young men. Daily β₂ -agonist treatment abolished several of the training-induced enhancements in muscle oxidative capacity and caused a repression of muscle metabolic pathways; furthermore, β₂ -agonist treatment induced a slow-to-fast twitch muscle phenotype transition. The present study indicates that chronic β₂ -agonist treatment confounds the positive effect of high intensity training on exercise performance and oxidative capacity, which is of interest for the large proportion of persons using inhaled β₂ -agonists on a daily basis, including athletes.

ABSTRACT

Although the effects of training have been studied for decades, data on muscle proteome signature remodelling induced by high intensity training in relation to functional changes in humans remains incomplete. Likewise, β₂ -agonists are frequently used to counteract exercise-induced bronchoconstriction, but the effects β₂ -agonist treatment on muscle remodelling and adaptations to training are unknown. In a placebo-controlled parallel study, we randomly assigned 21 trained men to 4 weeks of high intensity training with (HIT+β₂ A) or without (HIT) daily inhalation of β₂ -agonist (terbutaline, 4 mg dose^-1 ). Of 486 proteins identified by mass-spectrometry proteomics of muscle biopsies sampled before and after the intervention, 32 and 85 were changing (false discovery rate (FDR) ≤5%) with the intervention in HIT and HIT+β₂ A, respectively. Proteome signature changes were different in HIT and HIT+β₂ A (P = 0.005), wherein β₂ -agonist caused a repression of 25 proteins in HIT+β₂ A compared to HIT, and an upregulation of 7 proteins compared to HIT. β₂ -Agonist repressed or even downregulated training-induced enrichment of pathways related to oxidative phosphorylation and glycogen metabolism, but upregulated pathways related to histone trimethylation and the nucleosome. Muscle contractile phenotype changed differently in HIT and HIT+β₂ A (P ≤ 0.001), with a fast-to-slow twitch transition in HIT and a slow-to-fast twitch transition in HIT+β₂ A. β₂ -Agonist attenuated training-induced enhancements in maximal oxygen consumption (P ≤ 0.01) and exercise performance (6.1 vs. 11.6%, P ≤ 0.05) in HIT+β₂ A compared to HIT. These findings indicate that daily β₂ -agonist treatment attenuates the beneficial effects of high intensity training on exercise performance and oxidative capacity, and causes remodelling of muscle proteome signature towards a fast-twitch phenotype.

Bronchopulmonary pharmacokinetics of (R)-salbutamol and (S)-salbutamol enantiomers in pulmonary epithelial lining fluid and lung tissue of horses

AIMS

Salbutamol is usually administered as a racemic mixture but little is known about the enantioselectivity of salbutamol pharmacokinetics in the lung. This study was designed to investigate enantiomer concentrations in lung tissue after inhaled dosing.

METHODS

Horses (n = 12) received racemic salbutamol 1000 μg via inhalation. Enantioselective ultra performance liquid chromatography-tandem mass spectrometry was used to determine salbutamol concentrations in pulmonary epithelial lining fluid (PELF) sampled 2, 5, 10 and 15 min after administration, in central lung (endoscopic bronchial biopsy) and peripheral lung (percutaneous pulmonary biopsy) tissues (at 20 and 25 min respectively), and in plasma samples.

RESULTS

Mean ± 95% confidence interval (CI) yield of PELF was 57 ± 10 mg. Initial mean ± 95%CI (R)- and (S)-salbutamol PELF concentrations were 389 ± 189 ng g^-1 and 378 ± 177 ng g^-1 respectively, and both reduced approximately 50% by 15 min. Mean ± 95%CI central lung levels of drug were higher than peripheral lung tissue for both (R)-salbutamol (875 ± 945 vs. 49.5 ± 12 ng g^-1 ) and (S)-salbutamol (877 ± 955 vs. 50.9 ± 12 ng g^-1 ) respectively. There was no evidence of enantioselectivity in PELF or central lung but minor (~2%) enantioselectivity was observed in the peripheral lung. Enantioselectivity was clearly evident in plasma with (S):(R) ratio of 1.25 and 1.14 for both area under the concentration-time curve (0-25 min) and C_max respectively.

CONCLUSIONS

PELF sampling in horses offers sufficient yield allowing direct detection of drug and, combined with tissue sampling, is a valuable model to investigate bronchopulmonary pharmacokinetics. Salbutamol did not demonstrate enantioselectivity in PELF or central lung tissue uptake following acute dosing, however, enantioselective plasma concentrations were demonstrated, with minor enantioselectivity in the peripheral lung.

Enantioselective disposition of (R)-salmeterol and (S)-salmeterol in urine following inhaled dosing and application to doping control

Salmeterol (USAN, INN, BAN) is a long-acting beta2-adrenoceptor agonist (LABA) widely used in the treatment of airways disease. Although salmeterol is permitted via inhalation by athletes and supratherapeutic dosing may enhance performance, no urine threshold has been established by the World Anti-Doping Agency (WADA). Salmeterol is a chiral compound consisting of (R)- and (S)-enantiomers, normally administered as racemic (rac-) mixture via inhalation. Levels of rac-salmeterol in urine are often below detectable levels and there is surprisingly little information regarding the enantioselectivity of salmeterol pharmacokinetics. In this study, subjects inhaled either 50 (n = 6) or 200 µg (n = 4; generally regarded as maximum therapeutic dose) of salmeterol and urine was then collected for 24 h and analyzed by enantioselective ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Maximum rac-salmeterol urine concentrations were obtained at 2 h for both doses with medians of 0.084 ng/mL after the 50 µg dose and 2.1 ng/mL after the 200 µg dose, with an individual maximum of 5.7 ng/mL. Levels were detectable at 24 h for both doses. Salmeterol displayed enantioselective pharmacokinetics, with a mean ± SD log (S):(R) = 0.055 ± 0.025 (P < 0.0001) equivalent to (S):(R) of 1.13. In conclusion, rac-salmeterol by inhalation exhibits modest enantioselectivity in urine following single dose administration and can be detected following a single 50 µg dose for up to 24 h after inhalation. The present findings are of relevance if a urine threshold limit is to be introduced for salmeterol on the list of prohibited substances. The application of an enantiomer ratio analysis may offer improved discriminatory detection capability for doping control analysis applications. Copyright © 2016 John Wiley & Sons, Ltd.

Application of an assay for 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in urine for the assessment of tobacco-related harm

BACKGROUND

The tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), is formed from nicotine and related compounds during tobacco curing and is classified as a human carcinogen. Its major metabolite, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), is thought to be useful in the assessment of cigarette smoking harm minimisation strategies.

METHODOLOGY

Urine samples were collected from 24 current Caucasian smokers participating in a smoking cessation study; before and four weeks after a quit attempt. Samples were spiked with NNAL-d3 internal standard, extracted with ethyl acetate using liquid-liquid extraction, reconstituted with deionised water and analysed using ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS). Both free (unconjugated) and total NNAL was measured, with totals determined by cleavage of NNAL-glucuronide using standard enzymatic hydrolysis methods.

RESULTS

Free NNAL levels (193.5±158.2pg/mL [mean±standard deviation]) measured in urine samples obtained at baseline (during ad lib smoking) were indicative of biological exposure to NNK. Free NNAL levels were significantly reduced four weeks after the quit attempt (64.5±77.6pg/mL; p<0.002). Assay performance met acceptance criteria with mean recovery of 59±23%, intra-day accuracy was 3.7%, 3.7 and 3.6% and precision was 11.3%, 5.1% and 5.3% at 5pg/mL, 20pg/mL and 100pg/mL levels respectively. Enzymatic hydrolysis of NNAL-glucuronide proved unreliable with complete loss of NNAL aglycone in some subject samples following the hydrolysis procedure.

CONCLUSION

Liquid-liquid extraction with UPLC-MS/MS is a convenient approach to measure low levels of NNAL in urine as a marker of biological NNK exposure, which can be used to assess the effectiveness of smoking reduction harm minimisation strategies. Enzymatic hydrolysis of NNAL-glucuronide and measuring the aglycone is not recommended.

Reliability of Haemophilus influenzae biofilm measurement via static method, and determinants of in vitro biofilm production

Information is lacking regarding the precision of microtitre plate (MTP) assays used to measure biofilm. This study investigated the precision of an MTP assay to measure biofilm production by nontypeable Haemophilus influenzae (NTHi) and the effects of frozen storage and inoculation technique on biofilm production. The density of bacterial final growth was determined by absorbance after 18-20 h incubation, and biofilm production was then measured by absorbance after crystal violet staining. Biofilm formation was categorised as high and low for each strain. For the high biofilm producing strains of NTHi, interday reproducibility of NTHi biofilm formation measured using the MTP assay was excellent and met the acceptance criteria, but higher variability was observed in low biofilm producers. Method of inoculum preparation was a determinant of biofilm formation with inoculum prepared directly from solid media showing increased biofilm production for at least one of the high producing strains. In general, storage of NTHi cultures at -80 °C for up to 48 weeks did not have any major effect on their ability to produce biofilm.

Terbutaline: level the playing field for inhaled β2-agonists by introducing a dosing and urine threshold

Terbutaline, a short-acting β₂-agonist similar to salbutamol, is widely used in Europe in the treatment of asthma and exercise-induced bronchoconstriction. Unlike salbutamol, terbutaline requires therapeutic use exemption (TUE) for therapeutic inhaled use in competitive sport. There is now compelling evidence that supratherapeutic use of terbutaline is performance enhancing, via oral dosing and inhalation. It is likely that the ergogenic effects of terbutaline are class specific for all β₂-agonists. The World Anti-Doping Agency (WADA) has introduced dosing and urine threshold and decision limits for other common β₂-agonists. This allows athletes to use these drugs for therapeutic purposes while minimising the potential for doping and administrative burden of TUEs. However, no such threshold limits currently exist for terbutaline. For terbutaline, athletes can be granted a TUE, then administer the drug via inhalation at supratherapeutic doses with impunity. The introduction of threshold dosing and urine limits for terbutaline should be a high priority, given the drug's demonstrated ergogenic effects.

Safety and efficacy of kunzea oil-containing formulations for the management of psoriasis: a randomized, controlled trial

WHAT IS KNOWN AND OBJECTIVE

Anecdotally, topical kunzea oil has been used to treat various skin conditions, including psoriasis and eczema, with good results. This study compared the clinical efficacy of kunzea oil (20%)-containing formulations in mild to moderate psoriasis.

METHODS

A randomized, comparative, double-blind, 8-week study was undertaken. Thirty patients (age range: 25-74 years and mean ± SD: 52·8 ± 13·6 years) with mild to moderate psoriasis (affecting at least 10% of one or more body regions: arms, head, legs and trunk) randomly received ointment and/or scalp lotion containing 20% kunzea oil (test group) or control medications not containing kunzea oil (control group). Formulations in both treatment arms also contained 5% liquor carbonis detergens (LCD) and 3% salicylic acid. The clinical responses to the test and control formulations were evaluated using the Psoriasis Area and Severity Index (PASI).

RESULTS AND DISCUSSION

After 8 weeks of treatment, both test and control groups demonstrated a significant (P < 0·05) improvement in PASI scores. Subjects in the test group had a decrease in mean±SD PASI score from 12·7 ± 7·9 to 6·7 ± 7·2, whereas the control group showed a decrease in PASI score from 8·1 ± 4·6 to 3·5 ± 4·7. Comparative efficacy analysis between the test and control groups did not reveal any significant difference (P > 0·05).

WHAT IS NEW AND CONCLUSIONS

The inclusion of kunzea oil made no difference to the efficacy of topical formulations containing LCD and salicylic acid for the treatment of psoriasis.

Relationship between clinical site of isolation and ability to form biofilms in vitro in nontypeable Haemophilus influenzae

Nontypeable Haemophilus influenzae (NTHi) is an opportunistic pathogen associated with a range of infections, including various lower respiratory infections, otitis media, and conjunctivitis. There is some debate as to whether or not NTHi produces biofilms and, if so, whether or not this is relevant to pathogenesis. Although many studies have examined the association between in vitro biofilm formation and isolates from a specific infection type, few have made comparisons from isolates from a broad range of isolates grouped by clinical source. In our study 50 NTHi from different clinical sources, otitis media, conjunctivitis, lower respiratory tract infections in both cystic fibrosis and non-cystic fibrosis patients, and nasopharyngeal carriage, plus 10 nasopharyngeal isolates of the commensal Haemophilus haemolyticus were tested for the ability to form biofilm by using a static microtitre plate crystal violet assay. A high degree of variation in biofilm forming ability was observed across all isolates, with no statistically significant differences observed between the groups, with the exception of the isolates from conjunctivitis. These isolates had uniformly lower biofilm forming ability compared with isolates from the other groups (p < 0.005).

SULT 1A3 single-nucleotide polymorphism and the single dose pharmacokinetics of inhaled salbutamol enantiomers: are some athletes at risk of higher urine levels?

The study was designed to investigate the effect of a common genetic variation of the main salbutamol metabolizing enzyme SULT1A3 (single nucleotide polymorphism 105A>G, rs1975350) on the stereoselective pharmacokinetics of salbutamol. Subjects were administered a 400 µg dose of inhaled salbutamol via a large volume spacer and blood samples were collected over 4 h. Plasma levels of (R)- and (S)-salbutamol were determined by an enantioselective liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay. Twenty-five subjects with asthma were recruited and underwent SULT1A3 genotyping, from which four SNP homozygote (GG) subjects and nine wild-type (AA) subjects were selected to participated in the pharmacokinetic investigation. There were no differences in pharmacokinetic parameters (t1/2 , Cmax , AUC0-4h ) between SNP and wild-type genotypes for either the R- or S-enantiomer. Observed Cmax of R- and S-salbutamol [mean (SD)] was 0.64 (0.30) ng/mL and 1.32 (0.98) ng/mL, respectively. The mean t1/2 of R- and S-salbutamol was estimated at 2.94 (1.17) h and 7.86 (6.14) h respectively. The AUC0-4h of R- and S-salbutamol was 14.0 (6.8) and 38.3 (19.5) ng/mL.h respectively. In conclusion, the common SULT1A3 SNP 105A>G is not an important determinant of salbutamol enantiomer pharmacokinetics under normal clinical use and does not place some individuals at greater risk of accumulation in the body.

Enantioselective disposition of (R/S)-albuterol in skeletal and cardiac muscle

Significant enhancement of skeletal muscle function has been observed with racemic albuterol (salbutamol). There is now general acceptance that the R-albuterol enantiomer elicits the pharmacological response, both in the lungs and extrapulmonary, while S-albuterol is pharmacologically inert. The objective of this study was to investigate the distribution of (R/S)-albuterol enantiomers into skeletal and cardiac muscle. Initially oral dosing was undertaken in neonatal mice administered a maximum tolerable dose of racemic albuterol. An in vivo infusion rat model was employed for the investigation of albuterol uptake into skeletal and cardiac muscle over 4 h. Tissue concentrations were determined using liquid chromatography-tandem mass spectrometry (LC-MS/MS). From the oral dosing model, mean (±SD) levels of racemic albuterol after 5 days were 915 (±293) ng/mL in plasma, 2574 (±196) ng/g in muscle, and 53 (±6.6) ng/g in brain with enantioselective partitioning (muscle:plasma ratio of 5.7 and 1.7 for R- and S-albuterol, respectively). In the infusion model, enantioselective disposition was observed in skeletal muscle (muscle:plasma ratio of 1.2-1.7 and 0.6-0.7 for R- and S-albuterol, respectively) and in cardiac muscle (4.1 and 0.5, respectively). In conclusion, there is greater partitioning of active (R)-albuterol than inactive (S)-albuterol into both skeletal and cardiac muscle compared to plasma. These findings have relevance for albuterol sports doping, cardiac effects, and therapeutic use in muscle wasting diseases. Furthermore, the greater muscle partitioning of the active R-albuterol, and the availability of pure R-albuterol formulations highlight shortcomings in doping control measures using non-enantioselective assays.

Protoanemonin content variation between Clematis spp.: leaf, stem and root

The content of protoanemonin, a known biologically active constituent of Clematis spp., was determined by GC-MS in the leaf, stem and root extracts of one Chinese species and four Australian Clematis taxa. The results showed that protoanemonin concentrations varied between different plants and that leaves contained higher concentrations than stems and roots. To our knowledge this is the first study to determine protoanemonin content variation in leaf, stem and root of Clematis spp.

Protoanemonin Content Variation between Clematis spp.: Leaf, Stem and Root

The content of protoanemonin, a known biologically active constituent of Clematis spp., was determined by GC-MS in the leaf, stem and root extracts of one Chinese species and four Australian Clematis taxa. The results showed that protoanemonin concentrations varied between different plants and that leaves contained higher concentrations than stems and roots. To our knowledge this is the first study to determine protoanemonin content variation in leaf, stem and root of Clematis spp.

Proteoglycans in the central nervous system: role in development, neural repair, and Alzheimer's disease

Proteoglycans (PGs) are major components of the cell surface and extracellular matrix and play critical roles in development and maintenance of the central nervous system (CNS). PGs are a family of proteins, all of which contain a core protein to which glycosaminoglycan side chains are covalently attached. PGs possess diverse physiological roles, particularly in neural development, and are also implicated in the pathogenesis of neurodegenerative diseases such as Alzheimer's disease (AD). The main functions of PGs in the CNS are reviewed as are the roles of PGs in brain injury and in the development or treatment of AD.

Effects of heparin and enoxaparin on APP processing and Aβ production in primary cortical neurons from Tg2576 mice

BACKGROUND

Alzheimer's disease (AD) is caused by accumulation of Aβ, which is produced through sequential cleavage of β-amyloid precursor protein (APP) by the β-site APP cleaving enzyme (BACE1) and γ-secretase. Enoxaparin, a low molecular weight form of the glycosaminoglycan (GAG) heparin, has been reported to lower Aβ plaque deposition and improve cognitive function in AD transgenic mice.

METHODOLOGY/PRINCIPAL FINDINGS

We examined whether heparin and enoxaparin influence APP processing and inhibit Aβ production in primary cortical cell cultures. Heparin and enoxaparin were incubated with primary cortical cells derived from Tg2576 mice, and the level of APP and proteolytic products of APP (sAPPα, C99, C83 and Aβ) was measured by western blotting. Treatment of the cells with heparin or enoxaparin had no significant effect on the level of total APP. However, both GAGs decreased the level of C99 and C83, and inhibited sAPPα and Aβ secretion. Heparin also decreased the level of β-secretase (BACE1) and α-secretase (ADAM10). In contrast, heparin had no effect on the level of ADAM17.

CONCLUSIONS/SIGNIFICANCE

The data indicate that heparin and enoxaparin decrease APP processing via both α- and β-secretase pathways. The possibility that GAGs may be beneficial for the treatment of AD needs further study.

Albuterol enantiomer levels, lung function and QTc interval in patients with acute severe asthma and COPD in the emergency department

Background

This observational study was designed to investigate plasma levels of albuterol enantiomers among patients with acute severe asthma or COPD presenting to the emergency department, and the relationship with extra-pulmonary cardiac effects (QTc interval) and lung function. Recent reviews have raised concerns about the safety of using large doses of β₂-agonists, especially in patients with underlying cardiovascular comorbidity. It has been demonstrated that significant extrapulmonary effects can be observed in subjects given nebulised (R/S)-albuterol at a dose of as little as 6.5 mg.

Methods

Blood samples were collected and plasma/serum levels of (R)- and (S)-albuterol enantiomers were determined by LC-MS and LC-MS/MS assay. Extra-pulmonary effects measured at presentation included ECG measurements, serum potassium level and blood sugar level, which were collected from the hospital medical records.

Results

High plasma levels of both enantiomers were observed in some individuals, with median (range) concentrations of 8.2 (0.6-24.8) and 20.6 (0.5-57.3) ng/mL for (R)- and (S)- albuterol respectively among acute asthma subjects, and 2.1 (0.0-16.7) to 4.1 (0.0-36.1) ng/mL for (R)- and (S)- albuterol respectively among COPD subjects. Levels were not associated with an improvement in lung function or adverse cardiac effects (prolonged QTc interval).

Conclusions

High plasma concentrations of albuterol were observed in both asthma and COPD patients presenting to the emergency department. Extra-pulmonary cardiac adverse effects (prolonged QTC interval) were not associated with the plasma level of (R)- or (S)-albuterol when administered by inhaler in the emergency department setting. Long-term effect(s) of continuous high circulating albuterol enantiomer concentrations remain unknown, and further investigations are required.

In vitro antioxidant, antiplatelet and anti-inflammatory activity of Carpobrotus rossii (pigface) extract

ETHNOPHARMACOLOGICAL RELEVANCE

Carpobrotus rossii (CR) has a history of use as a food and therapeutic agent by Australian indigenous peoples and early European settlers and is believed to contain a number of pharmacologically active polyphenolic compounds.

AIMS OF THE STUDY

Oxidation of low density lipoprotein (LDL), platelet aggregation, and inflammation contribute to the development and progression of atherosclerosis. The aim of the present study was to investigate the antioxidant, antiplatelet and anti-inflammatory activity of CR extract using human blood components.

MATERIALS AND METHODS

An assay employing in vitro copper-induced oxidation of serum lipids was used to assess antioxidant activity of CR extract (and tannin, flavonoid and pre- and post-flavonoid fractions). The effects of CR extract on ADP- and collagen-induced platelet aggregation, and on basal (unstimulated) and lipopolysaccharide (LPS)- and phytohaemagglutinin A (PHA)-stimulated cytokine release from peripheral blood mononuclear cells (PBMC) were also investigated.

RESULTS

CR extract increased the lag time of serum oxidation (maximum of ∼4-fold at 20μg/ml) in a concentration-dependent manner. The antioxidant activity resided only in the tannin and post-flavonoid fractions. CR had no effect on ADP-induced platelet aggregation, but significantly decreased collagen-induced platelet aggregation. LPS, but not PHA, significantly increased the release of IL-1β and TNF-α from PBMC. CR extract alone inhibited monocyte chemoattractant protein (MCP)-1 release and in the presence of LPS, inhibited IL-10, TNF-α and MCP-1 release compared to LPS alone.

CONCLUSION

CR has significant in vitro antioxidant, antiplatelet and, potentially, anti-inflammatory activity.

Stability of ipratropium bromide and salbutamol nebuliser admixtures

The physicochemical stability of an admixture of ipratropium bromide and salbutamol nebuliser solutions, 1:1 v/v, was determined by storing solutions for five days in a refrigerator at 4C, at 22C protected from light and at 22C under 24 hour fluorescent lighting. Concentrations of ipratropium and salbutamol were periodically determined using a high performance liquid chromatography assay. The nebuliser solution admixtures retained greater than 90 per cent of their original concentrations of ipratropium and salbutamol for the duration of the study. Differences in losses between storage conditions were not statistically significant.

Admixtures of proprietary ipratropium bromide and salbutamol nebuliser solutions (1:1 v/v) retain greater than 90 per cent of their initial concentrations if stored between 4C and 22C for periods of up to five days. An expiry period of five days for these admixtures would seem reasonable in practice.

Evaluation of repellent properties of volatile extracts from the Australian native plant Kunzea ambigua against Aedes aegypti (Diptera: Culcidae)

Kunzea ambigua (Smith) Druce (Myrtaceae) is an Australian native plant, commonly known as tick bush. The essential oil of the plant has been proposed as a potential mosquito repellent. Commercial K. ambigua oil was analyzed by gas chromatography-mass spectrometry (GC-MS) and its composition compared with that of oils from two individual K. ambigua plants and citronella oil. K. ambigua oils were studied for their repellency against Aedes aegypti L. Formulations of three different K. ambigua essential oils (30% vol:vol) were tested for repellency to mosquitoes using human volunteers. One oil was compared with citronella and N,N'-diethyl-3-methylbenzamide (deet) for repellency. Oil formulations were also tested for repellency with and without the addition of 5% vanillin. The formulation containing commercially produced K. ambigua oil had a mean complete protection time (CPT) of 49 +/- 24 (SD) min. All the K. ambigua formulations had comparable repellency to 40% citronella. However, the 60% citronella formulation showed higher repellency than the 40% K. ambigua formulation. The addition of 5% vanillin did not increase the repellency of K. ambigua oil. Both K. ambigua oil and citronella were significantly less repellent than deet. The K. ambigua essential oil formulations should not be advocated for use as repellents in regions prone to mosquito-borne disease.

Investigation of the effect of heating on the chemistry and antifactor Xa activity of enoxaparin

The objective of this study was to investigate the effects of heating on the chemistry, physical properties and antifactor Xa activity of enoxaparin. Samples of enoxaparin heated at 70 degrees C lost 27% of their initial AFXa activity after 8 h, then activity increased to 94% of the initial activity over the next 4 h. Activity then decreased to 84% of control after 48 h and further to 80% of control over 22 days. The initial activity loss correlated with desulfation as demonstrated by sulfate and amine analysis. Fragmentation of oligosaccharides occurred, as demonstrated by reducing capacity and capillary electrophoresis analysis. Individual enoxaparin fractions obtained by high performance size exclusion chromatography were analysed. Early eluting fractions, containing aggregated oligosaccharides, increased in concentration following heating. Up to 65% of sulfate was lost from some fractions, containing hexa- and octa-saccharides, after 8 h, corresponding with decreased activity. Low mass oligosaccharide fractions increased in concentration and had increased activity between 8 and 12 h. Reversed-phase ion-interaction HPLC analysis supported these findings. Deca-, dodeca- and tetradeca-saccharides were resistant to thermal degradation. Desulfation, fragmentation and aggregation occur during the heating of enoxaparin and result in the initial rapid loss, recovery and subsequent gradual loss of activity.

Investigation of freezing- and thawing-induced biological, chemical, and physical changes to enoxaparin solution

This study investigated the effect of freezing and thawing on the biological, physical, and chemical properties of enoxaparin solution. Solutions were frozen and thawed under different conditions, in the presence or absence of dimethyl sulfoxide (DMSO) or 1,2-propanediol (1,2-PD), and the antifactor Xa (AFXa) activity was determined. Enoxaparin solution lost more than 60% of its AFXa activity when thawed rapidly after freezing at -196 degrees C. The loss of AFXa activity was less with higher freezing temperatures and increased with the number of freeze/thaw cycles, but was independent of the duration of freezing. Slow freezing to -196 degrees C with rapid thawing, or rapid freezing with slow thawing, resulted in negligible loss of AFXa activity. The loss of AFXa activity did not involve the loss of N-sulfate groups, the breakdown of glycosidic bonds or the glassy state transition. Controlling the freezing or thawing conditions, dilution with water or addition of a small percentage of DMSO ameliorated the loss of enoxaparin AFXa activity. The loss in AFXa activity was found by size exclusion chromatography to be primarily due to aggregation and was reversed by sonication in the presence of DMSO. These results may provide insight into solutions for the long-term storage of concentrated or diluted enoxaparin.

Volatile organic compounds in runners near a roadway: increased blood levels after short-duration exercise

OBJECTIVE

To determine if non-elite athletes undertaking short duration running exercise adjacent to a busy roadway experience increased blood levels of common pollutant volatile organic compounds (benzene, toluene, ethylbenzene and xylene (BTEX)).

DESIGN AND SETTING

The study was observational in design. Participants (nine males/one female non-elite athletes) ran for 20 min, near a busy roadway along a 100 m defined course at their own pace. Blood levels of BTEX were determined both pre- and post-exercise by SPME-GC-MS. Environmental BTEX levels were determined by passive adsorption samplers.

RESULTS

Subjects completed a mean (range) distance of 4.4 (3.4 to 5.2) km over 20 min (4.5 (3.8 to 5.9) min/km pace), with a mean (SD) exercise intensity of 93 (2.3)% HR(max), and mean (SD) ventilation significantly elevated compared with resting levels (86.2 (2.3) vs 8.7 (0.9) l/min; p<0.001). The mean (SD) environmental levels (time weighted average) were determined as 53.1 (4.2), 428 (83), and 80.0 (3.7) microg/m(3) for toluene, ethylbenzene and xylenes, respectively, while benzene was below the detectable limit due to the short exposure period. Significant increases in blood BTEX levels were observed in runners between pre- and postexercise for toluene (mean increase of 1.4 ng/ml; p=0.002), ethylbenzene (0.7 ng/ml; p=0.0003), m/p-xylene (2.0 ng/ml; p=0.004) and o-xylene (1.1 ng/ml; p=0.002), but no change was observed for benzene.

CONCLUSIONS

Blood BTEX levels are increased during high-intensity exercise such as running undertaken in areas with BTEX pollution, even with a short duration of exercise. This may have health implications for runners who regularly exercise near roadways.

A simple capillary electrophoresis method for the rapid separation and determination of intact low molecular weight and unfractionated heparins

A simple, selective and accurate capillary electrophoresis (CE) method has been developed for the rapid separation and identification of various low molecular weight heparins (LMWHs) and unfractionated heparin. Separation and operational parameters were investigated using dalteparin sodium as the test LMWH. The developed method used a 70 cm fused silica capillary (50 microm i.d.) with a detection window 8.5 cm from the distal end. Phosphate electrolyte (pH 3.5; 50 mM), an applied voltage of -30 k V, UV detection at 230 nm and sample injection at 20 mbar for 5s were used. The method performance was assessed in terms of linearity, selectivity, intra- and inter-day precision and accuracy. The method was successfully applied to the European Pharmacopeia LMWH standard, dalteparin sodium, enoxaparin sodium and heparin sodium with a significant reduction in the run time and increased resolution compared with previously reported CE methods. Different CE separation profiles were obtained for various LMWHs and unfractionated heparin showing significant structural diversity. The current methodology was sensitive enough to reveal minor constituent differences between two different batches of enoxaparin sodium. This CE method also clearly showed chemical changes that occurred to LMWHs under different stress conditions. The sensitivity, selectivity and simplicity of the developed method allow its application in research or manufacturing for the identification, stability analysis, characterization and monitoring of batch-to-batch consistency of different low molecular weight and unfractionated heparins.

Elevated plasma glutathione peroxidase concentration in acute severe asthma: comparison with plasma glutathione peroxidase activity, selenium and malondialdehyde

OBJECTIVE

To investigate plasma glutathione peroxidase concentration, glutathione peroxidase activity, plasma selenium and oxidative stress in acute severe asthma.

MATERIAL AND METHODS

The study was case-control in design, with cases presenting to the emergency department with acute severe asthma and controls randomly selected from a larger cross-sectional study. Plasma malondialdehyde (MDA) was used as a measure of oxidative stress and plasma selenium was measured using ICP-MS. Glutathione peroxidase (GPx) activity was analysed using a colorimetric GPx assay and plasma GPx level was measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Fifteen cases [mean (range) predicted peak expiratory flow rate (PEFR) of 43% (20-69)] and 15 matched controls were recruited. MDA levels (mean+/-SD) were higher in acute asthma subjects (1.30+/-0.56 micromol/L) than in controls (0.86+/-0.53 micromol/L; p<0.05). There were no differences between cases and controls for selenium (99+/-34 microg/L versus 109+/-17 microg/L) or for GPx activity (39+/-25 nmol min(-1) mL(-1) versus 38+/-24 nmol min(-1) mL(-1)), however, GPx plasma levels measured by ELISA were higher in cases than controls (22.5+/-10.8 mg/L versus 13.8+/-7.3 mg/L; p<0.05).

CONCLUSIONS

Patients with acute severe asthma demonstrated increased MDA levels but no differences in plasma selenium levels or GPx activity. GPx levels measured by ELISA were elevated in severe asthma. These results are consistent with an adaptive up-regulation of GPx to protect against oxidative stress.

Effect of celecoxib on cyclooxygenase-2 expression and possible variants in a patient with Barrett's esophagus

Cyclooxygenase-2 (COX-2) expression is increased in metaplastic and dysplastic Barrett's esophageal epithelium and it is thought that selective COX-2 inhibitors could offer hope as chemoprevention therapy. The aim of the study was to investigate the in vivo effect of celecoxib on COX-2 expression in patients with Barrett's esophagus and no recent history of non-steroidal anti-inflammatory drug use. Endoscopic mucosal biopsy specimens were collected at baseline and after 28 days of therapy in a patient treated with celecoxib 200 mg twice daily. Samples were analyzed for COX-2 expression by immunoblot analysis with chemiluminescence detection. COX-2 expression was found to decline 20% and 44% at two different biopsy sites compared to the baseline sample. Longer exposures revealed a number of previously unidentified proteins above and below the 67 kDa COX-2 protein including 38 kDa and 45 kDa proteins which were present only at study completion consistent with up-regulation after celecoxib therapy. Further investigations of the 38 kDa and 45 kDa proteins were undertaken using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) with immunoblot and MALDI-TOF (matrix assisted laser desorption ionization - time of flight) analysis but no matches were found and results were inconclusive. Unmatched masses from MALDI-TOF peptide mass fingerprinting were compared with human COX-2 (67 kDa) and COX-2b (39 kDa) using unspecific cleavage. Peptide sequence homology with COX-2 and COX-2b was found for a length of 19 amino acids. Based on immunodetection, molecular weight and equivical MALDI-TOF results, one of these up-regulated proteins may be COX-2b.