ptairMS: real-time processing and analysis of PTR-TOF-MS data for biomarker discovery in exhaled breath.

MOTIVATION: Analysis of volatile organic compounds (VOCs) in exhaled breath by proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) is of increasing interest for real-time, non-invasive diagnosis, phenotyping and therapeutic drug monitoring in the clinics. However, there is currently a lack of methods and software tools for the processing of PTR-TOF-MS data from cohorts and suited for biomarker discovery studies. RESULTS: We developed a comprehensive suite of algorithms that process raw data from patient acquisitions and generate the table of feature intensities. Notably, we included an innovative two-dimensional peak deconvolution model based on penalized splines signal regression for accurate estimation of the temporal profile and feature quantification, as well as a method to specifically select the VOCs from exhaled breath. The workflow was implemented as the ptairMS software, which contains a graphical interface to facilitate cohort management and data analysis. The approach was validated on both simulated and experimental datasets, and we showed that the sensitivity and specificity of the VOC detection reached 99% and 98.4%, respectively, and that the error of quantification was below 8.1% for concentrations down to 19 ppb. AVAILABILITY AND IMPLEMENTATION: The ptairMS software is publicly available as an R package on Bioconductor (doi: 10.18129/B9.bioc.ptairMS), as well as its companion experiment package ptairData (doi: 10.18129/B9.bioc.ptairData). SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Volatile metabolites differentiate air-liquid interface cultures after infection with Staphylococcus aureus.

Early detection of lung infection is critical to clinical diagnosis, treatment, and monitoring. Measuring volatile organic compounds (VOCs) in exhaled breath has shown promise as a rapid and accurate method of evaluating disease metabolism and phenotype. However, further investigations of the role and function of VOCs in bacterial-host-stress response is required and this can only be realised through representative in vitro models. In this study we sampled VOCs from the headspace of A549 cells at an air-liquid interface (ALI). We hypothesised VOC sampling from ALI cultures could be used to profile potential biomarkers of S. aureus lung infection. VOCs were collected using thin film microextraction (TFME) and were analysed by thermal desorption-gas chromatography-mass spectrometry. After optimising ALI cultures, we observed seven VOCs changed between A549 and media control samples. After infecting cells with S. aureus, supervised principal component-discriminant function analysis revealed 22 VOCs were found to be significantly changed in infected cells compared to uninfected cells (p < 0.05), five of which were also found in parallel axenic S. aureus cultures. We have demonstrated VOCs that could be used to identify S. aureus in ALI cultures, supporting further investigation of VOC analysis as a highly sensitive and specific test for S. aureus lung infection.

Alternative routes for tranexamic acid treatment in obstetric bleeding (WOMAN-PharmacoTXA trial): a randomised trial and pharmacological study in caesarean section births.

OBJECTIVE: To examine the safety, efficacy and pharmacology of intravenous (IV), intramuscular (IM) and oral tranexamic acid (TXA) use in pregnant women. DESIGN: Randomised, open-label trial. SETTING: Hospitals in Pakistan and Zambia. POPULATION: Women giving birth by caesarean section. METHODS: Women were randomised to receive 1 g IV, 1 g IM, 4 g oral TXA or no TXA. Adverse events in women and neonates were recorded. TXA concentration in whole blood was measured and the concentrations over time were examined with population pharmacokinetics. The relationship between drug exposure and D-dimer was explored. The trial registration is NCT04274335. MAIN OUTCOME MEASURES: Concentration of TXA in maternal blood. RESULTS: Of the 120 women included in the randomised safety study, there were no serious maternal or neonatal adverse events. TXA concentrations in 755 maternal blood and 87 cord blood samples were described by a two-compartment model with one effect compartment linked by rate transfer constants. Maximum maternal concentrations were 46.9, 21.6 and 18.1 mg/L for IV, IM and oral administration, respectively, and 9.5, 7.9 and 9.1 mg/L in the neonates. The TXA response was modelled as an inhibitory effect on the D-dimer production rate. The half-maximal inhibitory concentration (IC50 ) was 7.5 mg/L and was achieved after 2.6, 6.4 and 47 minutes with IV, IM and oral administration of TXA, respectively. CONCLUSIONS: Both IM and oral TXA are well tolerated. Oral TXA took about 1 hour to reach minimum therapeutic concentrations and would not be suitable for emergency treatment. Intramuscular TXA inhibits fibrinolysis within 10 minutes and may be a suitable alternative to IV.

Pharmacokinetics of tranexamic acid after intravenous, intramuscular, and oral routes: a prospective, randomised, crossover trial in healthy volunteers.

BACKGROUND: In response to the World Health Organization call for research on alternative routes for tranexamic acid (TXA) administration in women with postpartum haemorrhage, we examined the pharmacokinetics of TXA after i.v., i.m., or oral administration. METHODS: We conducted a randomised, open-label, crossover trial in 15 healthy volunteers who received i.v. TXA 1 g, i.m. TXA 1 g, or oral TXA solution 2 g. Blood samples were drawn up to 24 h after administration. Tranexamic acid concentration was measured with liquid chromatography-mass spectrometry, and the parameters of the pharmacokinetic models were estimated using population pharmacokinetics. RESULTS: The median time to reach a concentration of 10 mg L-1 was 3.5 min for the i.m. route and 66 min for the oral route, although with the oral route the target concentration was reached in only 11 patients. Median peak concentrations were 57.5, 34.4, and 12.8 mg L-1 for i.v., i.m., and oral routes, respectively. A two-compartment open model with body weight as the main covariate best fitted the data. For a 70 kg volunteer, the population estimates were 10.1 L h-1 for elimination clearance, 15.6 L h-1 for intercompartmental clearance, 7.7 L for the volume of central compartment, and 10.8 L for the volume of the peripheral compartment. Intramuscular and oral bioavailabilities were 1.0 and 0.47, respectively, showing that i.m. absorption is fast and complete. Adverse events were mild and transient, mainly local reactions and low-intensity pain. CONCLUSIONS: The i.m. (but not oral) route appears to be an efficient alternative to i.v. tranexamic acid. Studies in pregnant women are needed to examine the impact of pregnancy on the pharmacokinetics. CLINICAL TRIAL REGISTRATION: EudraCT 2019-000285-38; NCT03777488.

Population pharmacokinetics of ropivacaine used for local infiltration anaesthesia during primary total unilateral and simultaneous bilateral knee arthroplasty.

BACKGROUND: Ropivacaine is commonly used in local infiltration anaesthesia (LIA) as pain management after total knee arthroplasty (TKA). Although considered safe, no studies evaluated the pharmacokinetics of high-dose ropivacaine infiltration in simultaneous bilateral TKA. METHODS: We studied 13 patients undergoing unilateral and 15 undergoing bilateral TKA. Standard LIA technique was used with ropivacaine 0.2%, 200 ml (400 mg) injected peri-articularly in each knee. Free and total plasma concentrations of ropivacaine were measured within 24 h using liquid chromatography-mass spectrometry. A population pharmacokinetic model was built using non-linear mixed-effects models. RESULTS: Peak free ropivacaine concentration was 0.030 (0.017-0.071) µg ml-1 (mean [99% confidence interval]) vs 0.095 (0.047-0.208) µg ml-1, and peak total ropivacaine concentration was 0.756 (0.065-1.222) µg ml-1vs 1.695 (0.077-3.005) µg ml-1 for unilateral and bilateral TKA, respectively. The pharmacokinetics was ascribed a one-compartment model with first-order absorption. The main identified covariates were protein binding, allometrically scaled body weight on clearance and volume, and unilateral or bilateral surgery on volume. CONCLUSIONS: This is the first study to investigate the pharmacokinetics of free and total ropivacaine after unilateral and bilateral TKA. A population model was successfully built and peak free ropivacaine concentration stayed below previously proposed toxic thresholds in patients undergoing unilateral and bilateral TKA receiving LIA with high-dose ropivacaine. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04702282.

Pharmacokinetics of intramuscular tranexamic acid in bleeding trauma patients: a clinical trial.

BACKGROUND: Intravenous tranexamic acid (TXA) reduces bleeding deaths after injury and childbirth. It is most effective when given early. In many countries, pre-hospital care is provided by people who cannot give i.v. injections. We examined the pharmacokinetics of intramuscular TXA in bleeding trauma patients. METHODS: We conducted an open-label pharmacokinetic study in two UK hospitals. Thirty bleeding trauma patients received a loading dose of TXA 1 g i.v., as per guidelines. The second TXA dose was given as two 5 ml (0·5 g each) i.m. injections. We collected blood at intervals and monitored injection sites. We measured TXA concentrations using liquid chromatography coupled to mass spectrometry. We assessed the concentration time course using non-linear mixed-effect models with age, sex, ethnicity, body weight, type of injury, signs of shock, and glomerular filtration rate as possible covariates. RESULTS: Intramuscular TXA was well tolerated with only mild injection site reactions. A two-compartment open model with first-order absorption and elimination best described the data. For a 70-kg patient, aged 44 yr without signs of shock, the population estimates were 1.94 h-1 for i.m. absorption constant, 0.77 for i.m. bioavailability, 7.1 L h-1 for elimination clearance, 11.7 L h-1 for inter-compartmental clearance, 16.1 L volume of central compartment, and 9.4 L volume of the peripheral compartment. The time to reach therapeutic concentrations (5 or 10 mg L-1) after a single intramuscular TXA 1 g injection are 4 or 11 min, with the time above these concentrations being 10 or 5.6 h, respectively. CONCLUSIONS: In bleeding trauma patients, intramuscular TXA is well tolerated and rapidly absorbed. CLINICAL TRIAL REGISTRATION: 2019-000898-23 (EudraCT); NCT03875937 (ClinicalTrials.gov).

Chloroquine Inhibits the Release of Inflammatory Cytokines by Human Lung Explants.

On human lung parenchymal explants, chloroquine concentration clinically achievable in the lung (100 µM) inhibited the lipopolysaccharide-induced release of TNF-ɑ (by 76%), IL-6 (by 68%), CCL2 (by 72%), and CCL3 (by 67%). Besides its antiviral activity, chloroquine might also mitigate the cytokine storm associated with severe pneumonia caused by coronaviruses.

Validation according to European and American regulatory agencies guidelines of an LC-MS/MS method for the quantification of free and total ropivacaine in human plasma.

Background Ropivacaine is a widely used local anaesthetic drug, highly bound to plasma proteins with a free plasma fraction of about 5%. Therefore, the monitoring of free drug concentration is most relevant to perform pharmacokinetic studies and to understand the drug pharmacokinetic/pharmacodynamic (PK/PD) relationship. Methods A high-sensitivity liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using reverse-phase LC and electrospray ionisation mass spectrometry with multiple reaction monitoring (MRM) is described for the quantitation of both free and total ropivacaine in human plasma. Ropivacaine-d7 was used as an internal standard (IS). Results The method was validated in the range 0.5-3000 ng/mL, with five levels of QC samples and according to the European Medicine Agency and Food and Drug Administration guidelines. The performance of the method was excellent with a precision in the range 6.2%-14.7%, an accuracy between 93.6% and 113.7% and a coefficient of variation (CV) of the IS-normalised matrix factor below 15%. This suitability of the method for the quantification of free and total ropivacaine in clinical samples was demonstrated with the analysis of samples from patients undergoing knee arthroplasty and receiving a local ropivacaine infiltration. Conclusions A method was developed and validated for the quantification of free and total ropivacaine in human plasma and was shown suitable for the analysis of clinical samples.

An Experimental Study of Paclitaxel Embolisation During Drug Coated Balloon Angioplasty.

OBJECTIVE: Drug coated balloons (DCB) improve the patency of femoropopliteal angioplasty but their use in infrapopliteal lesions is debateable as paclitaxel (PTX) particle embolisation has been suspected in some trials. The aim of this study was to compare experimentally five DCBs in terms of distal embolism of PTX. METHODS: Twenty-five New Zealand rabbits were divided into five groups according to the DCB used: Lutonix (Bard), In.Pact (Medtronic), Passeo-18 Lux (Biotronik), Ranger (Boston Scientific), and Stellarex (Spectranetics) (n = 5 in each group). After ligation of the right common iliac artery, a 4 × 40 mm DCB was inflated in the infrarenal aorta for 180 seconds. Rabbits were euthanised two hours after inflation of the DCB. The infrarenal aorta, a blood sample and three left hind leg muscles (tensor fasciae latae [TFL], vastus lateralis [VL], and tibialis anterior [TA] muscles) were harvested for blind measurement of PTX concentrations and histological analysis (PTX emboli count). RESULTS: In the TA muscle (the most distal), concentrations of PTX were significantly lower for the Ranger (0.067 ng/mg) than for the Lutonix (0.342 ng/mg; p = .008), In.Pact (0.370 ng/mg; p = .012), and Passeo-18-Lux (0.160 ng/mg; p = .021) DCBs. Similarly, concentrations of PTX were significantly lower for the Passeo-18-Lux than for the In.Pact (p = .028). Concentrations of PTX were not significantly different between DCBs in the TFL and VL muscles. Concentrations of PTX were found to be significantly higher in the plasma and lower in the aorta and on the DCBs after use of Lutonix compared with the four other DCBs. Histological analysis revealed evidence of embolised PTX crystals in small arterioles of all muscle tissue samples without any significant difference between the DCBs. CONCLUSIONS: This study suggests some differences regarding distal embolisation profiles between the five assessed DCBs. Although clinical implications remain to be demonstrated, the present results may have implications when choosing a DCB, especially in a critical limb ischaemia setting.

Comparison of the in vitro pharmacological profiles of long-acting muscarinic antagonists in human bronchus.

BACKGROUND AND PURPOSE: Long-acting muscarinic antagonists (LAMAs) have been recommended for the treatment of chronic obstructive pulmonary disease and (more recently) asthma. However, the in vitro pharmacological profiles of the four LAMAs currently marketed (tiotropium, umeclidinium, aclidinium and glycopyrronium) have not yet been compared (relative to ipratropium) by using the same experimental approach. EXPERIMENTAL APPROACH: With a total of 560 human bronchial rings, we investigated the antagonists' potency, onset and duration of action for inhibition of the contractile response evoked by electrical field stimulation. We also evaluated the antagonists' potency for inhibiting cumulative concentration-contraction curves for acetylcholine and carbachol. KEY RESULTS: The onset and duration of action were concentration-dependent. At submaximal, equipotent concentrations, the antagonists' onsets of action were within the same order of magnitude. However, the durations of action differed markedly. After washout, ipratropium's inhibitory activity decreased rapidly (within 30-90 min) but those of tiotropium and umeclidinium remained stable (at above 70%) for at least 9 h. Aclidinium and glycopyrronium displayed less stable inhibitory effects, with a progressive loss of inhibition at submaximal concentrations. In contrast to ipratropium, all the LAMAs behaved as insurmountable antagonists by decreasing the maximum responses to both acetylcholine and carbachol. CONCLUSIONS AND IMPLICATIONS: The observed differences in the LAMAs' in vitro pharmacological profiles in the human bronchus provide a compelling pharmacological rationale for the differences in the drugs' respective recommended daily doses and frequencies of administration.

Pharmacokinetics of cefuroxime in infants and neonates undergoing cardiac surgery.

AIMS: Very little data exist regarding the effect of cardiopulmonary bypass (CPB) on cefuroxime (CXM) pharmacokinetics in children less than one year of age. METHODS: 50 mg kg-1 CXM i.v. after induction were followed by 75 mg kg-1 into the CPB circuit. In 42 patients undergoing cardiac surgery, 15-20 samples were obtained between 5 and 360 min after the first dose. Total CXM concentrations were measured by high-performance liquid chromatography and a pharmacokinetic/pharmacodynamic (PK/PD) modelling was performed. RESULTS: Using a fixed protein binding of 15.6% for CXM, peak plasma concentrations of unbound CXM were 229 ± 52 µg ml-1 after the first bolus and 341 ± 86 µg ml-1 on CPB. Nadir concentrations before CPB were 69 ± 20 µg ml-1 and six hours later decreased to 41 ± 19 µg ml-1 with and 24 ± 14 µg ml-1 without CPB. A two-compartment model was fitted with the main covariates body weight, CPB and postmenstrual age (PMA). PK parameters were as follows: systemic clearance, 5.15 [95% CI 4.5-5.8] l h-1 ; central volume of distribution, 11.25 [9.41-13.09] l; intercompartmental clearance, 18.19 [14.79-21.58] l h-1 ; and peripheral volume, 17.07 [15.7-18.5] L. ƒT > MIC of 32 µg ml-1 for an 8-h time period was between 70 and 100% (2.5-10 kg BW). According to our simulation, 25 mg ml-1 CXM as a primary bolus and into the prime plus a 5 mg kg-1  h-1 infusion maintain CXM concentrations continuously above 32 µg ml-1 . CONCLUSIONS: The routine dosing regimen provided was sufficient for prophylaxis, but continuous dosing can provide a higher percentage of ƒT > MIC.

In smokers, Sonic hedgehog modulates pulmonary endothelial function through vascular endothelial growth factor.

BACKGROUND: Tobacco-induced pulmonary vascular disease is partly driven by endothelial dysfunction. The Sonic hedgehog (SHH) pathway is involved in vascular physiology. We sought to establish whether the SHH pathway has a role in pulmonary endothelial dysfunction in smokers. METHODS: The ex vivo endothelium-dependent relaxation of pulmonary artery rings in response to acetylcholine (Ach) was compared in 34 current or ex-smokers and 8 never-smokers. The results were expressed as a percentage of the contraction with phenylephrine. We tested the effects of SHH inhibitors (GANT61 and cyclopamine), an SHH activator (SAG) and recombinant VEGF on the Ach-induced relaxation. The level of VEGF protein in the pulmonary artery ring was measured in an ELISA. SHH pathway gene expression was quantified in reverse transcriptase-quantitative polymerase chain reactions. RESULTS: Ach-induced relaxation was much less intense in smokers than in never-smokers (respectively 24 ± 6% and 50 ± 7% with 10-4M Ach; p = 0.028). All SHH pathway genes were expressed in pulmonary artery rings from smokers. SHH inhibition by GANT61 reduced Ach-induced relaxation and VEGF gene expression in the pulmonary artery ring. Recombinant VEGF restored the ring's endothelial function. VEGF gene and protein expression levels in the pulmonary artery rings were positively correlated with the degree of Ach-induced relaxation and negatively correlated with the number of pack-years. CONCLUSION: SHH pathway genes and proteins are expressed in pulmonary artery rings from smokers, where they modulate endothelial function through VEGF.

Human lung and monocyte-derived macrophages differ with regard to the effects of ß2-adrenoceptor agonists on cytokine release.

BACKGROUND: ß2-adrenoceptor agonists have been shown to reduce the lipopolysaccharide (LPS)-induced cytokine release by human monocyte-derived macrophages (MDMs). We compare the expression of ß2-adrenoceptors and the inhibitory effect of formoterol and salmeterol on the LPS-induced release of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6 and a range of chemokines (CCL2, 3, 4, and IL-8) by human lung macrophages (LMs) and MDMs. METHODS: LMs were isolated from patients undergoing resection and MDMs were obtained from blood monocytes in the presence of GM-CSF. LMs and MDMs were incubated in the absence or presence of formoterol or salmeterol prior to stimulation with LPS. The effects of formoterol were also assessed in the presence of the phosphodiesterase inhibitor roflumilast. RESULTS: LPS-induced cytokine production was higher in LMs than in MDMs. Salmeterol and formoterol exerted an inhibitory effect on the LPS-induced production of TNF-α, IL-6, CCL2, CCL3, and CCL4 in MDMs. In contrast, the ß2-adrenoceptor agonists were devoid of any effect on LMs - even in the presence of roflumilast. The expression of ß2-adrenergic receptors was detected on Western blots in MDMs but not in LMs. CONCLUSIONS: Concentrations of ß2-adrenoceptor agonists that cause relaxation of the human bronchus can inhibit cytokine production by LPS-stimulated MDMs but not by LMs.

Pharmacokinetics of tranexamic acid in neonates and infants undergoing cardiac surgery.

AIM: Tranexamic acid (TXA) continues to be one of the antifibrinolytics of choice during paediatric cardiac surgery. However, in infants less than 1 year of age, the optimal dosing based on pharmacokinetic (PK) considerations is still under discussion. METHODS: Forty-three children less than 1 year of age were enrolled, of whom 37 required the use of cardiopulmonary bypass (CPB) and six were operated on without CPB. Administration of 50 mg kg-1 TXA intravenously at the induction of anaesthesia was followed by 50 mg kg-1 into the CPB prime in the CPB group. Plasma concentrations of TXA were analysed by gas chromatography-mass spectrometry. PK data were investigated using nonlinear mixed-effect models. RESULTS: A two-compartment model was fitted, with the main covariates being allometrically scaled bodyweight, CPB, postmenstrual age (PMA). Intercompartmental clearance (Q), peripheral volume (V2), systemic clearance, (CL) and the central volume (V1) were calculated. Typical values of the PK parameter estimates were as follows: CL = 3.78 [95 % confidence interval (CI) 2.52, 5.05] l h-1 ; central volume of distribution = 13.6 (CI 11.7, 15.5) l; Q = 16.3 (CI 13.5, 19.2) l h-1 ; V2 = 18.0 (CI 16.1, 19.9) l. Independently of age, 10 mg kg-1 TXA as a bolus, a subsequent infusion of 10 mg kg-1 h-1 , then a 4 mg kg-1 bolus into the prime and a reduced infusion of 4 mg kg-1 h-1 after the start of CPB are required to maintain TXA concentrations continuously above 20 µg ml-1 , the threshold value for an effective inhibition of fibrinolysis and far lower than the usual peak concentrations (the '10-10-4-4 rule'). CONCLUSIONS: The introduction of a modified dosing regimen using a starting bolus followed by an infusion and a CPB prime bolus would prohibit the potential risk of seizures caused by high peak concentrations and also maintain therapeutic plasma concentration above 20 µg ml-1 .

Detection and quantification of 12 anabolic steroids and analogs in human whole blood and 20 in hair using LC-HRMS/MS: application to real cases.

We developed and validated a method to detect and quantify 12 anabolic steroids in blood (androstenedione, dihydrotestosterone, boldenone, epitestosterone, mesterolone, methandienone, nandrolone, stanozolol, norandrostenedione, tamoxifene, testosterone, trenbolone) and eight more in hair samples (nandrolone phenylpropionate, nandrolone decanoate, testosterone propionate, testosterone benzoate, testosterone cypionate, testosterone decanoate, testosterone phenylpropionate, testosterone undecanoate) using liquid chromatography coupled to high-resolution mass spectrometry. This method used a benchtop Orbitrap mass spectrometer operating with an APCI probe under positive ionization mode. Analysis was realized in full scan experiment with a nominal resolving power of 140,000. After addition of the internal standard (testosterone-D3) and incubation in phosphate buffer pH = 5 for hair, 200 µL of blood and 30 mg of hair samples were extracted with heptane. LOQ and LOD were determined at 5 and 1 ng mL-1 in whole blood and 10 to 100 pg mg-1 and 2 to 20 pg mg-1 in hair according to the compounds, respectively. The method was linear in the 5-1000 ng mL-1 range in whole blood and between 10 or 100 pg mg-1 and 1000 pg mg-1 in hair with correlation coefficients >0.99, and intra- and inter-day accuracy and precision were <14.8% for all compounds except for some esters in hairs (<19.9%) probably due to an important matrix effect for these compounds. This sensitive and specific method to detect anabolic steroids has been successfully applied to two real cases, for which various anabolic steroids in whole blood, urine, and hair were identified and quantified.

The impact of low-frequency, low-force cyclic stretching of human bronchi on airway responsiveness.

BACKGROUND: In vivo, the airways are constantly subjected to oscillatory strain (due to tidal breathing during spontaneous respiration) and (in the event of mechanical ventilation) positive pressure. This exposure is especially problematic for the cartilage-free bronchial tree. The effects of cyclic stretching (other than high-force stretching) have not been extensively characterized. Hence, the objective of the present study was to investigate the functional and transcriptional response of human bronchi to repetitive mechanical stress caused by low-frequency, low-force cyclic stretching. METHODS: After preparation and equilibration in an organ bath, human bronchial rings from 66 thoracic surgery patients were stretched in 1-min cycles of elongation and relaxation over a 60-min period. For each segment, the maximal tension corresponded to 80% of the reference contraction (the response to 3 mM acetylcholine). The impact of cyclic stretching (relative to non-stretched controls) was examined by performing functional assessments (epithelium removal and incubation with sodium channel agonists/antagonists or inhibitors of intracellular pathways), biochemical assays of the organ bath fluid (for detecting the release of pro-inflammatory cytokines), and RT-PCR assays of RNA isolated from tissue samples. RESULTS: The application of low-force cyclic stretching to human bronchial rings for 60 min resulted in an immediate, significant increase in bronchial basal tone, relative to non-cyclic stretching (4.24 ± 0.16 g vs. 3.28 ± 0.12 g, respectively; p < 0.001). This cyclic stimulus also increased the affinity for acetylcholine (-log EC50: 5.67 ± 0.07 vs. 5.32 ± 0.07, respectively; p p < 0.001). Removal of airway epithelium and pretreatment with the Rho-kinase inhibitor Y27632 and inward-rectifier K+ or L-type Ca2+ channel inhibitors significantly modified the basal tone response. Exposure to L-NAME had opposing effects in all cases. Pro-inflammatory pathways were not involved in the response; cyclic stretching up-regulated the early mRNA expression of MMP9 only, and was not associated with changes in organ bath levels of pro-inflammatory mediators. CONCLUSION: Low-frequency, low-force cyclic stretching of whole human bronchi induced a myogenic response rather than activation of the pro-inflammatory signaling pathways mediated by mechanotransduction.

Comparison of outcome measures in allergic rhinitis in children, adolescents and adults.

BACKGROUND: Grass pollen-induced allergic rhinoconjunctivitis (AR) is very common worldwide. However, its symptoms may vary with the patient's age. The present study compared symptom profiles and quality of life (QoL) in children, adolescents and adults with grass pollen-induced AR. METHODS: This was a four-week, multicentre, observational study of children (aged 6-11), adolescents (12-17) and adults (18-65) consulting specialist physicians in France. The management of AR was at the physicians' discretion. Participants regularly rated their symptoms (the rhinoconjunctivitis total symptom score (RTSS) and a visual analogue scale (VAS)) and QoL (the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ). RESULTS: A total of 806 patients (253 children, 250 adolescents and 303 adults, of whom 83.5% suffered from moderate-to-severe, persistent AR) provided data for at least the first 2 weeks of the study. Ocular pruritus (the most bothersome symptom in children (35%), adolescents (22%) and adults (16%)) was associated with poor QoL in all groups, whereas nasal obstruction and pruritus were associated with poor QoL in adolescents and children. Over 4 weeks, the weekly mean RTSS and VAS scores fell by around half. This change was associated with an improvement in the RQLQ scores. In all age groups, the VAS score was well correlated with the weekly mean RTSS score (Pearson's r: 0.79-0.88) and moderately correlated with the weekly mean RQLQ score (Pearson's r: 0.64-0.80). CONCLUSIONS: In moderate-to-severe grass pollen-induced AR, symptom perception differs in children vs. older patients. However, the assessments of treatment outcomes (using the RTSS, VAS and RQLQ) were similar in all age groups.

Cannabinoid receptor 1 is a major mediator of renal fibrosis.

Chronic kidney disease, secondary to renal fibrogenesis, is a burden on public health. There is a need to explore new therapeutic pathways to reduce renal fibrogenesis. To study this, we used unilateral ureteral obstruction (UUO) in mice as an experimental model of renal fibrosis and microarray analysis to compare gene expression in fibrotic and normal kidneys. The cannabinoid receptor 1 (CB1) was among the most upregulated genes in mice, and the main endogenous CB1 ligand (2-arachidonoylglycerol) was significantly increased in the fibrotic kidney. Interestingly, CB1 expression was highly increased in kidney biopsies of patients with IgA nephropathy, diabetes, and acute interstitial nephritis. Both genetic and pharmacological knockout of CB1 induced a profound reduction in renal fibrosis during UUO. While CB2 is also involved in renal fibrogenesis, it did not potentiate the role of CB1. CB1 expression was significantly increased in myofibroblasts, the main effector cells in renal fibrogenesis, upon TGF-ß1 stimulation. The decrease in renal fibrosis during CB1 blockade could be explained by a direct action on myofibroblasts. CB1 blockade reduced collagen expression in vitro. Rimonabant, a selective CB1 endocannabinoid receptor antagonist, modulated the macrophage infiltrate responsible for renal fibrosis in UUO through a decrease in monocyte chemoattractant protein-1 synthesis. Thus, CB1 has a major role in the activation of myofibroblasts and may be a new target for treating chronic kidney disease.

Comparison of two doses of tranexamic acid in adults undergoing cardiac surgery with cardiopulmonary bypass.

BACKGROUND: The optimal dose of tranexamic acid (TA) is still an issue. The authors compared two doses of TA during cardiac surgery in a multicenter, double-blinded, randomized study. METHODS: Patients were stratified according to transfusion risk, then randomized to two TA doses: 10 mg/kg bolus followed by 1 mg·kg·h infusion (low dose) until the end of surgery or 30 mg/kg bolus followed by 16 mg·kg·h infusion (high dose). The primary endpoint was the incidence of blood product transfusion up to day 7. Secondary ones were incidences of transfusion for each type of blood product and amounts transfused, blood loss, repeat surgery, TA-related adverse events, and mortality. RESULTS: The low-dose group comprised 284 patients and the high-dose one 285. The primary endpoint was not significantly different between TA doses (63% for low dose vs. 60% for high dose; P = 0.3). With the high dose, a lower incidence of frozen plasma (18 vs. 26%; P = 0.03) and platelet concentrate (15 vs. 23%; P = 0.02) transfusions, lower amounts of blood products (2.5 ± 0.38 vs. 4.1 ± 0.39; P = 0.02), fresh frozen plasma (0.49 ± 0.14 vs.1.07 ± 0.14; P = 0.02), and platelet concentrates transfused (0.50 ± 0.15 vs. 1.13 ± 0.15; P = 0.02), lower blood loss (590 ± 50.4 vs. 820 ± 50.7; P = 0.01), and less repeat surgery (2.5 vs. 6%; P = 0.01) were observed. These results are more marked in patients with a high risk for transfusion. CONCLUSIONS: A high dose of TA does not reduce incidence of blood product transfusion up to day 7, but is more effective than a low dose to decrease transfusion needs, blood loss, and repeat surgery.

Comparison of the potency of different propofol formulations: a randomized, double-blind trial using closed-loop administration.

BACKGROUND: Several commercial formulations of propofol are available. The primary outcome of this study was the required dose of propofol alone or combined with lidocaine to achieve induction of general anesthesia. METHODS: This multicenter, double-blinded trial randomized patients (American Society of Anesthesiologists physical status I-III) just before elective surgery with the use of a computer-generated list. Three different propofol 1% formulations-Diprivan (Astra-Zeneca, Cheshire, United Kingdom), Propoven (Fresenius-Kabi AG, Bad Homburg, Germany), and Lipuro (B-Braun, Melshungen AG, Germany)-were compared with either placebo (saline solution) or lidocaine 1% mixed to the propofol solution. Depth of anesthesia was automatically guided by bispectral index and by a computerized closed-loop system for induction, thus avoiding dosing bias. The authors recorded the total dose of propofol and duration of induction and the patient's discomfort through a behavioral scale (facial expression, verbal response, and arm withdrawal) ranging from 0 to 6. The authors further evaluated postoperative recall of pain using a Visual Analog Scale. RESULTS: Of the 227 patients enrolled, 217 were available for analysis. Demographic characteristics were similar in each group. Propoven required a higher dose for induction (2.2 ± 0.1 mg/kg) than Diprivan (1.8 ± 0.1 mg/kg) or Lipuro (1.7 ± 0.1 mg/kg; P = 0.02). However, induction doses were similar when propofol formulations were mixed with lidocaine. Patient discomfort during injection was significantly reduced with lidocaine for every formulation: Diprivan (0.5 ± 0.3 vs. 2.3 ± 0.3), Propoven (0.4 ± 0.3 vs. 2.4 ± 0.3), and Lipuro (1.1 ± 0.3 vs. 1.4 ± 0.3), all differences significant, with P < 0.0001. No adverse effect was reported. CONCLUSION: Plain propofol formulations are not equipotent, but comparable doses were required when lidocaine was concomitantly administered.