Assessment of a flow cytometry technique for studying signaling pathways in platelets: Monitoring of VASP phosphorylation in clinical samples

A recently released kit (PerFix EXPOSE) was reported to improve the measurement of the degree of phosphorylation of proteins in leukocytes by flow cytometry. We tested its adaptation for platelets to monitor vasodilator-stimulated phosphoprotein (VASP) phosphorylation, which is the basis of a currently used test for the assessment of the pharmacological response to P2Y12 antagonists (PLT VASP/P2Y12). The PerFix EXPOSE kit was compared to the PLT VASP/P2Y12 kit by using blood samples drawn at 24 h post clopidogrel dose from 19 patients hospitalized for a non-cardio-embolic ischemic stroke and treated with clopidogrel monotherapy for at least five days in an observational study. The platelet PerFix method was based on adaptation of the volume of the sample, the centrifugation speed and the incubation temperature. Poor agreement between prevention by adenosine diphosphate (ADP) of PGE₁-induced cAMP-mediated VASP phosphorylation and ADP induced aggregation assessed by Light Transmittance Aggregometry was found. We found a significant correlation between the PLT VASP/P2Y12 kit and the PerFix EXPOSE kit. The PerFix EXPOSE kit may also be helpful to monitor adverse effects of second-generation tyrosine kinase inhibitors on platelets.

Influence of environmental and anthropogenic factors on the composition, concentration and spatial distribution of microplastics: A case study of the Bay of Brest (Brittany, France)

The concentration and spatial distribution of microplastics in the Bay of Brest (Brittany, France) was investigated in two surveys. Surface water and sediment were sampled at nine locations in areas characterized by contrasting anthropic pressures, riverine influences or water mixing. Microplastics were categorized by their polymer type and size class. Microplastic contamination in surface water and sediment was dominated by polyethylene fragments (PE, 53-67%) followed by polypropylene (PP, 16-30%) and polystyrene (PS, 16-17%) microparticles. The presence of buoyant microplastics (PE, PP and PS) in sediment suggests the existence of physical and/or biological processes leading to vertical transfer of lightweight microplastics in the bay. In sediment (upper 5 cm), the percentage of particles identified by Raman micro-spectroscopy was lower (41%) than in surface water (79%) and may explain the apparent low concentration observed in this matrix (0.97 ± 2.08 MP kg^-1 dry sediment). Mean microplastic concentration was 0.24 ± 0.35 MP m^-3 in surface water. We suggest that the observed spatial MP distribution is related to proximity to urbanized areas and to hydrodynamics in the bay. A particle dispersal model was used to study the influence of hydrodynamics on surface microplastic distribution. The outputs of the model showed the presence of a transitional convergence zone in the centre of the bay during flood tide, where floating debris coming from the northern and southern parts of the bay tends to accumulate before being expelled from the bay. Further modelling work and observations integrating (i) the complex vertical motion of microplastics, and (ii) their point sources is required to better understand the fate of microplastics in such a complex coastal ecosystem.

Smokers and Postcessation Weight Gain After Acute Coronary Syndrome

Background

Smoking cessation and weight management are recommended after acute coronary syndrome (ACS); however, little is known about the effects of smoking cessation on weight change after ACS. We aimed to assess the effect of smoking cessation after ACS on weight over a 12‐month follow‐up period.

Methods and Results

Data were prospectively collected from the EVITA (Evaluation of Varenicline in Smoking Cessation for Patients Post‐Acute Coronary Syndrome) trial. Weight change was compared among 3 groups of patients: those who were completely abstinent (n=70), those who smoked intermittently (n=68), and those who smoked persistently (n=34). Patients' mean baseline weight was 83.9 kg (SD 17.7) with a mean body mass index of 28.5 (SD 5.4). Patients smoked a mean of 37.7 years (SD 17.7) and a mean of 21.0 cigarettes (SD 9.0) per day prior to their ACS. Weight change varied across groups, with abstainers gaining a mean of 4.8 kg (SD 8.6), intermittent smokers gaining a mean of 2.0 kg (SD 8.9) and persistent smokers losing a mean of 0.7 kg (SD 7.4). At 52 weeks, abstainers were more likely to gain weight than persistent smokers (difference in means 5.5 kg; 95% CI 2.3–8.8). This weight gain was not associated with an increase in the use of antihypertensive or antidiabetic medications.

Conclusions

Following an ACS, significant weight is gained by patients who quit smoking. Weight‐management interventions among smokers who quit after ACS should be a focus of investigation in future research so that the cardiovascular benefits achieved by smoking cessation are not offset by weight gain in this high‐risk population.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00794573.

New tools in cytometry

Cytometry aims to analyze cells, of any type, using dedicated instruments. The quantitative aspect makes flow cytometry (FCM) a good complementary tool for morphology. Most of the identification tools are based on immunostaining of cell structure details and more and more tools are available in terms of specificities and labels. FCM is under exponential development thanks to technical, immunological and data analysis progresses. Actual generations are now routinely using 6 to 10 simultaneous immuno-labeling on 20 to 100,000 cells, at high speed and short sample preparation and can easily detect rare events at frequency below 10^-4 cells. Data interpretation is complex and requires expertise. Mathematical tools are available to support analysis and classification of cells based. Cells from tissues can also be analyzed by FCM after mechanical and or enzymatic separation, but in situ cells can also be analyzed with the help of cytometry. Very new instruments bring spectral analysis, image in flow and mass spectrometry. Medical applications are very broad, notably in hemopathies, immunology, solid tumors, but also microbiology, toxicology, drug discovery, food and environmental industry. But, the limit of FCM is its dependence on operator from sample preparation, instrument settings up to data analysis and a strong effort is now under progress for standardization and constitution of international data bank for references and education.

GOSPEL 2 - Colchicine for the treatment of gout flares in France - a GOSPEL survey subgroup analysis. Doses used in common practices regardless of renal impairment and age

OBJECTIVES

The objective of this sub-study was to assess the use of colchicine for the treatment of gout flares in real life conditions in the GOSPEL cohort following the 2006 EULAR recommendations for gout management.

METHODS

This national cross-sectional epidemiologic survey included outpatients with gout suffering from acute flare followed by randomly selected primary care physicians (n=398) and private practice rheumatologists (n=109) between October 2008 and September 2009 in France. Data regarding patient characteristics and treatment prescription was collected by each physician. Glomerular filtration rate (eGFR) was estimated using the Cockroft-Gault formula. Patients included in the survey for a gout flare filled in a specific self-questionnaire including colchicine effective intake and pain relief (numeric scale).

RESULTS

This analysis focused on the 349 patients presenting with gout flare and treated with colchicine. Mean (±SD) prescribed dose of colchicine was 2.8 (±0.7) mg within the first 24hours and the cumulative dose over the first three days of treatment was 6.9 (±1.8) mg. Patients with mild decline in eGFR (eDFG 60-80mL/min) were prescribed an average initial dose of 2.8mg (±0.8) mg (n=58), 2.7 (±0.8) mg in chronic kidney disease (CKD) stage 3 (n=43) and 2.5 (±0.7) mg in CKD stage 4 (n=2). Cumulative doses of colchicine did not take into account either renal impairment or age.

CONCLUSIONS

This study draws attention to some misuse of colchicine in daily practice and the prescription of excessive doses especially in case of renal impairment. eGFR should be enforced in daily practice.

Prospective Phase II Trial of Once-weekly Hypofractionated Radiation Therapy for Low-risk Adenocarcinoma of the Prostate: Late Toxicities and Outcomes

AIMS

To report the long-term toxicities and sexual quality of life of a once-weekly hypofractionated radiation therapy schedule for low-risk prostate cancer.

MATERIALS AND METHODS

A multi-institutional phase II trial was conducted, using a three-dimensional conformal radiation therapy (3D-CRT) approach for low-risk prostate cancer (T1a-T2a, Gleason ≤ 6 and prostate-specific antigen ≤ 10 ng/ml). Forty-five Gray (Gy) were delivered in nine fractions of 5 Gy given on a weekly basis. Acute and late genitourinary and gastrointestinal toxicities were graded according to the Radiation Therapy Oncology Group toxicity scale. Sexual function and sexual bother were assessed with the Expanded Prostate Cancer Index Composite (EPIC) questionnaire.

RESULTS

Between March 2006 and August 2008, 80 patients were treated, with a median age of 69 years (interquartile range 64-72). The median follow-up was 83 months (interquartile range 73-85 months). At 7 years, overall survival was 88%. No patients died of prostate cancer. Cumulative grade ≥2 genitourinary and gastrointestinal late toxicity was reported for 31.3% and 30% of our patients, respectively. Cumulative grade ≥3 genitourinary and gastrointestinal late toxicity was seen in 3.8% and 12.5% of cases, respectively. Late genitourinary grade 2 toxicity was correlated with the occurrence of acute genitourinary grade 2 toxicity (P = 0.006). The occurrence of late gastrointestinal toxicity was not correlated with acute gastrointestinal toxicity. Pre-treatment EPIC sexual function was low (37.5%) and the mean EPIC sexual function score at 7 years after treatment was 14%. On the other hand, pre-treatment EPIC sexual bother reached 80.5%, meaning little bother, and remained stable during follow-up.

CONCLUSIONS

Once-weekly 3D-CRT leads to excellent biochemical disease-free survival and acceptable toxicities. Pre-treatment EPIC sexual function dropped by 42% at 5 years of follow-up. This functional deficit did not bother patients, possibly due to the already low sexual function at baseline.