Pitfalls and potential of high-throughput plant phenotyping platforms.

Automated high-throughput plant phenotyping (HTPP) enables non-invasive, fast and standardized evaluations of a large number of plants for size, development, and certain physiological variables. Many research groups recognize the potential of HTPP and have made significant investments in HTPP infrastructure, or are considering doing so. To make optimal use of limited resources, it is important to plan and use these facilities prudently and to interpret the results carefully. Here we present a number of points that users should consider before purchasing, building or utilizing such equipment. They relate to (1) the financial and time investment for acquisition, operation, and maintenance, (2) the constraints associated with such machines in terms of flexibility and growth conditions, (3) the pros and cons of frequent non-destructive measurements, (4) the level of information provided by proxy traits, and (5) the utilization of calibration curves. Using data from an Arabidopsis experiment, we demonstrate how diurnal changes in leaf angle can impact plant size estimates from top-view cameras, causing deviations of more than 20% over the day. Growth analysis data from another rosette species showed that there was a curvilinear relationship between total and projected leaf area. Neglecting this curvilinearity resulted in linear calibration curves that, although having a high r2 (> 0.92), also exhibited large relative errors. Another important consideration we discussed is the frequency at which calibration curves need to be generated and whether different treatments, seasons, or genotypes require distinct calibration curves. In conclusion, HTPP systems have become a valuable addition to the toolbox of plant biologists, provided that these systems are tailored to the research questions of interest, and users are aware of both the possible pitfalls and potential involved.

Handheld device quantifies breath acetone for real-life metabolic health monitoring.

Non-invasive breath analysis with mobile health devices bears tremendous potential to guide therapeutic treatment and personalize lifestyle changes. Of particular interest is the breath volatile acetone, a biomarker for fat burning, that could help in understanding and treating metabolic diseases. Here, we report a hand-held (6 × 10 × 19.5 cm3), light-weight (490 g), and simple device for rapid acetone detection in breath. It comprises a tailor-made end-tidal breath sampling unit, connected to a sensor and a pump for on-demand breath sampling, all operated using a Raspberry Pi microcontroller connected with a HDMI touchscreen. Accurate acetone detection is enabled by introducing a catalytic filter and a separation column, which remove and separate undesired interferents from acetone upstream of the sensor. This way, acetone is detected selectively even in complex gas mixtures containing highly concentrated interferents. This device accurately tracks breath acetone concentrations in the exhaled breath of five volunteers during a ketogenic diet, being as high as 26.3 ppm. Most importantly, it can differentiate small acetone changes during a baseline visit as well as before and after an exercise stimulus, being as low as 0.5 ppm. It is stable for at least four months (122 days), and features excellent bias and precision of 0.03 and 0.6 ppm at concentrations below 5 ppm, as validated by proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS). Hence, this detector is highly promising for simple-in-use, non-invasive, and routine monitoring of acetone to guide therapeutic treatment and track lifestyle changes.

Accuracy of gradient diffusion method for susceptibility testing of dalbavancin and comparators.

OBJECTIVES: This multicenter study aimed to assess the performances of gradient diffusion (GD) method in comparison to broth microdilution (BMD) method for susceptibility testing of dalbavancin, daptomycin, vancomycin, and teicoplanin. METHODS: Minimum Inhibitory Concentrations (MICs) were retrospectively determined concomitantly by BMD and GD methods, for 93 staphylococci and enterococci isolated from clinical samples. BMD was considered as the gold standard. Essential (EA) and categorical agreements (CA) were calculated. Discordant categorical results were categorized as major (ME) and very major errors (VME). RESULTS: EA and CA were 95.7% and 96.8%, 82.8% and 100%, 97.8% and 96.8%, and 94.6% and 95.7% for dalbavancin, daptomycin, vancomycin, and teicoplanin respectively. Concerning dalbavancin, 3 ME without any VME were observed and discrepancies were low (≤ to 2 two-fold dilutions) between both methods. VME were noted in 1 and 3 cases for vancomycin and teicoplanin, respectively, and resulted from 1 two-fold dilution discrepancy in each case. EA was lower for daptomycin. When they were discrepant, BMD MICs were systematically higher than GD ones. Nevertheless, no categorical discrepancy was noted. CONCLUSIONS: GD appears as an acceptable and convenient alternative for dalbavancin, vancomycin, and teicoplanin MICs determination. Our study also emphasizes how achieving accurate daptomycin MICs remains challenging.

Should we reconsider cefazolin for treating staphylococcal meningitis? A retrospective analysis of cefazolin and cloxacillin cerebrospinal fluid levels in patients treated for staphylococcal meningitis.

OBJECTIVES: To assess the meningeal penetration of cefazolin and cloxacillin in individuals treated for methicillin-susceptible staphylococcal meningitis. METHODS: We retrospectively identified individuals treated for Staphylococcus meningitis with measurements of cefazolin or cloxacillin concentrations in cerebrospinal fluid (CSF) using a validated assay of liquid chromatography coupled with mass spectrometry at the Nantes University Hospital between January 2009 and October 2019. Staphylococcus meningitis was defined by a compatible clinical presentation and a microbiological confirmation (positive CSF culture or positive specific PCR). Medical charts were retrospectively reviewed to collect microbiological and clinical data, and to assess therapeutic success. RESULTS: Among the 17 included individuals, eight (47%) were treated with cefazolin and nine (53%) with cloxacillin. Median daily dosages of cefazolin and cloxacillin were 8 g (range 6-12 g) and 12 g (range 10-13 g), respectively. Cefazolin and cloxacillin were mainly administered by continuous infusion. Eleven individuals (65%) were men, median (interquartile range (IQR)) age was 54 years (50; 70), 14 (82%) had postoperative meningitis and 3 (18%) had haematogenous meningitis. Median (IQR) antibiotic CSF concentrations were 2.8 mg/L (2.1; 5.2) and 0.66 mg/L (0.5; 0.9) for cefazolin and cloxacillin groups, respectively. Cloxacillin was discontinued in two individuals for therapeutic failure. CONCLUSIONS: Patients with staphylococcal meningitis treated with high-dose continuous intravenous infusion of cefazolin achieved therapeutic concentrations in CSF. Cefazolin appears to be a therapeutic candidate that should be properly evaluated in this indication.

PK/PD targets of amikacin and gentamicin in ICU patients.

OBJECTIVES: We aimed to evaluate the probability to achieve PK-PD targets in patients with sepsis hospitalized in the intensive care unit (ICU) after a single dose of 30mg/kg of amikacin or 8mg/kg of gentamicin. PATIENTS AND METHODS: This single-center prospective study included 138 ICU patients with severe sepsis or septic shock with an indication for intravenous amikacin (N=89) or gentamicin (N=49). Maximum concentration (Cmax) was measured 30 minutes after infusion completion. PK/PD objectives were respectively Cmax≥60mg/L and ≥30mg/L for amikacin and gentamicin for empirical therapy, and a Cmax/MIC ratio≥8, as per French guidelines. RESULTS: The median Simplified Acute Physiology Score II was 43 and ICU case fatality rate was 34.8%. A causative bacterial agent was identified in 94 patients (68.1%). Three pathogens had acquired aminoglycoside resistance and 15 were naturally resistant. The targeted Cmax for the first dose was achieved in 53 patients (59.6%) receiving amikacin, and one (2.2%) patient receiving gentamicin. Cmax/MIC ratio≥8 was obtained in all patients infected with susceptible pathogens (N=72). Factors associated with Cmax≥60mg/L of amikacin in multivariate analysis were dose per kg of adapted body weight (OR=1.39, P<0.001) and renal clearance estimated with CKD-EPI formula (OR=0.98, P=0.003). CONCLUSIONS: Despite high doses, amikacin and gentamicin first Cmax remain dramatically low in ICU patients. However, an adequate Cmax/MIC ratio was reached in all patients.

Switching from abacavir/lamivudine plus nevirapine to abacavir/lamivudine/dolutegravir in virologically controlled HIV-infected adults (SWAD study).

INTRODUCTION: The metabolic pathways of dolutegravir suggest a potential predator effect of nevirapine on dolutegravir pharmacokinetics and switching from a nevirapine- to a dolutegravir-containing regimen could lead to a lower and suboptimal exposure to dolutegravir several weeks after the switch in case of persistent inducer effect. PATIENTS AND METHOD: Prospective, pilot, single-arm, open-label, non-comparative, bicentric study to evaluate the pharmacokinetics, virologic outcomes, safety, and patient satisfaction of switching from abacavir/lamivudine and nevirapine to a single tablet of abacavir/lamivudine/dolutegravir. The primary endpoint was the maintenance of virologic suppression (HIV-1 RNA<50 copies/mL) at week 12. Secondary endpoints were virologic suppression at week 48, safety and tolerability, patient satisfaction, and pharmacokinetic interaction between nevirapine and dolutegravir. Fifty-three adults on stable abacavir/lamivudine and nevirapine regimen for a median duration of 6years and virologically suppressed for 9.6years were included. RESULTS: Dolutegravir reached steady state by week 4/week 12 when expected by day 5/day 10. All subjects maintained plasma HIV-RNA˂50 copies/mL at week 12 and week 48. Abacavir/lamivudine/dolutegravir was well-tolerated, with two cases of serious adverse events deemed unrelated to study drugs (coronary syndrome in both cases), and one discontinuation for renal impairment at week 24 with a slight improvement after dolutegravir discontinuation. Level of treatment satisfaction remained high after the switch. CONCLUSION: The transient predator effect of nevirapine on dolutegravir had no clinical consequences after switching from nevirapine to dolutegravir, neither on safety nor maintenance of virologic suppression. It also had no consequences on patient satisfaction.

Cefazolin tissue concentrations with a prophylactic dose administered before sleeve gastrectomy in obese patients: a single centre study in 116 patients.

BACKGROUND: In obese patients undergoing sleeve gastrectomy, the blood and fatty-tissue concentrations of cefazolin required for adequate antibiotic prophylaxis are uncertain. METHODS: This was a single centre prospective study in obese (Group A: 40≤ BMI ≤50 kg m-2) and severely obese (Group B: 50< BMI ≤65 kg m-2) patients undergoing bariatric surgery. Blood and fatty-tissue samples were collected after a cefazolin 4 g i.v. injection. The primary aim was to compare cefazolin concentrations in subcutaneous fatty tissue with a targeted tissue concentration of 4 µg g-1 according to Staphylococcus aureus resistance breakpoint. RESULTS: One hundred and sixteen patients were included: 79 in Group A and 37 in Group B. At the beginning of the surgery, cefazolin concentration in subcutaneous fatty tissue was 12.2 (5.4) µg g-1 in Group A and 12 (6.1) µg g-1 in Group B (P=0.7). At the end, cefazolin concentrations in subcutaneous fatty tissue were 9.0 (4.9) and 7.8 (4.2) µg g-1 in Groups A and B, respectively (P=0.2). The plasma concentration of free cefazolin during surgery was higher in Group A than in Group B (P<0.0001). Fatty-tissue concentrations of 95% and 83% patients in Groups A and B, respectively, were above S. aureus resistance breakpoint. CONCLUSIONS: After a 4 g dose, the concentrations of cefazolin in fatty tissue were above the 4 µg g-1 tissue concentration target, providing adequate antibiotic tissue concentrations during bariatric surgery. As cefazolin concentration in fatty tissue is a surrogate endpoint, the results should be considered in conjunction with the results on free cefazolin concentrations in subcutaneous tissue. CLINICAL TRIAL REGISTRATION: NCT01537380.

Systematic review: human gut dysbiosis induced by non-antibiotic prescription medications.

BACKGROUND: Global prescription drug use has been increasing continuously for decades. The gut microbiome, a key contributor to health status, can be altered by prescription drug use, as antibiotics have been repeatedly described to have both short-term and long-standing effects on the intestinal microbiome. AIM: To summarise current findings on non-antibiotic prescription-induced gut microbiome changes, focusing on the most frequently prescribed therapeutic drug categories. METHODS: We conducted a systematic review by first searching in online databases for indexed articles and abstracts in accordance with PRISMA guidelines. Studies assessing the intestinal microbiome alterations associated with proton pump inhibitors (PPIs), metformin, nonsteroidal anti-inflammatory drugs (NSAIDs), opioids, statins and antipsychotics were included. We only included studies using culture-independent molecular techniques. RESULTS: Proton pump inhibitors and antipsychotic medications are associated with a decrease in α diversity in the gut microbiome, whereas opioids were associated with an increase in α diversity. Metformin and NSAIDs were not associated with significant changes in α diversity. ß diversity was found to be significantly altered with all drugs, except for NSAIDs. PPI use was linked to a decrease in Clotridiales and increase in Actinomycetales, Micrococcaceae and Streptococcaceae, which are changes previously implicated in dysbiosis and increased susceptibility to Clostridium difficile infection. Consistent results showed that PPIs, metformin, NSAIDs, opioids and antipsychotics were either associated with increases in members of class Gammaproteobacteria (including Enterobacter, Escherichia, Klebsiella and Citrobacter), or members of family Enterococcaceae, which are often pathogens isolated from bloodstream infections in critically ill patients. We also found that antipsychotic treatment, usually associated with an increase in body mass index, was marked by a decreased ratio of Bacteroidetes:Firmicutes in the gut microbiome, resembling trends seen in obese patients. CONCLUSIONS: Non-antibiotic prescription drugs have a notable impact on the overall architecture of the intestinal microbiome. Further explorations should seek to define biomarkers of dysbiosis induced by specific drugs, and potentially tailor live biotherapeutics to counter this drug-induced dysbiosis. Many other frequently prescribed drugs should also be investigated to better understand the link between these drugs, the microbiome and health status.

Binary zero-order diffractive and anti-reflective optical elements in silicon for the mid-infrared.

We propose a novel method for the design of binary two-level diffractive optical elements that provide an efficient diffractive function while reducing the reflectivity of a high-index interface. The structure can be fabricated with a single patterning step and is particularly useful for the mid-infrared spectral range. The concept is based on zero-order transmission gratings using subwavelength microstructures. To demonstrate the concept a Dammann grating has been realized in silicon and characterized in the mid-infrared by scanning the far-field intensity distribution.

Repeated exposure to others' pain reduces vicarious pain intensity estimation.

BACKGROUND: Pain perception in others can be influenced by different contextual factors. In clinical settings, the repeated exposure to others' pain has been proposed as a factor that could explain underestimation of patients' pain by health care providers. Previous research supported this idea by showing that repeated exposure to persons in pain biases the subsequent willingness to impute pain in others. However, it remains unclear if the effect of repeated exposure on the detection of pain extends to deliberate pain estimation of stimuli presented for a longer period. METHOD: Therefore, in a first experiment, healthy participants were either exposed to clips of facial expressions of intense pain or neutral expressions before estimating the intensity of other individuals' pain expressions. To test the specificity of this effect with regard to the pain content, a second study was conducted with healthy adults, which compared the effect of exposure to fear, pain and neutral videos on subsequent pain assessment in others. RESULTS: Results from the first experiment indicated that repeated exposure to others' pain diminished the subsequent estimation of the intensity of pain in others. Results from the second experiment suggested that exposure to fear could bias pain estimation in a similar manner. However, the absence of difference in ratings between the exposure to fear and neutral groups warrants caution in the interpretation of these findings. CONCLUSION: By demonstrating that repeated exposure to others' pain diminished subsequent pain estimation in others, this study adds relevant information on the factors that could contribute to pain underestimation in health care professionals. WHAT DOES THIS STUDY ADD?: Repeated exposure to facial expressions of intense pain not only biases pain detection, but also pain estimation in others. Prior exposure to facial expressions of pain compared to exposure to neutral ones leads to a reduced estimation of others' pain. This effect is not specific to pain as exposure to another negative emotion (fear) also biases subsequent pain estimation. These results support the interpretation that the underestimation of patients' pain by health care professionals could be related to repeated exposure to other's pain.

[Cathinones use in Paris]. / Usage de cathinones à Paris.

BACKGROUND: The pattern of recreational drug use has changed over the last decade and now includes a multitude of substances sold as "research chemicals" or new psychoactive substances, "NPS". In France, synthetic cathinones emerged in 2008 (while first mentioned by the French police force in 2007 first alerts among users appeared in 2008) and have grown to be popular drugs of abuse. Under the Official Journal dated 11th June 2010, only mephedrone has been listed as narcotics but "designer drugs" have synthesized new substitute cathinones in order to avoid anti-drug laws. However, since July 2012, in France, all synthetic drugs from the cathinones family have been banned and listed as narcotics following the example of United Kingdom. Despite their recent classification and inclusion on narcotic list, they are readily available on Internet and used widely. Paris Addictovigilance Centre observed a signal of derivate cathinones abuse (21 cases over a two-year period). OBJECTIVE: Paris Addictovigilance Centre and Marmottan Hospital wanted to describe the use of cathinones in the Paris area and alert the health care community about the abuse identification and risk assessment problems of these compounds. After a review of derivated cathinone's chemical structure, pharmacology and toxicology, this article seeks to provide patricians with a clinical description and treatment's modality. RESULTS: Most users of synthetic cathinones will experience euphoria, increased energy, talkativeness, openness and increased sexual arousal. Signs and symptoms of toxicity are consistent with a sympathomimetic toxidrome. The main reasons for care access are psychiatric (hallucinations, psychotic symptoms, agitation) and addiction disorders. Somatic complications were described with various patterns of symptoms such as headache, tachycardia, confusional states, rhabdomyolysis with renal failure or serotonin syndrome. The most important fact is the apparition of the "slam" phenomenon among men who have sex with men (MSM). The "slam" is a compound of three characteristic elements: injection, sexual party and psychostimulant drug. According to users, "slam" is convenient for group sex and is used it to put them into a good mood and a disinhibition state. These compounds cause fast dependence syndrome with strong craving and prolonged psychiatric symptoms and increase infectious risk (HIV, VHC, VHB…). The cathinones family is not detected in conventional urine drug screenings. We point out the lack of confirmatory analytic testing data which remains the only way to determine the actual etiology of the clinical effects observed since drug users do not always know exactly what they took. These substances can be identified by special analyses using gas chromatography or liquid chromatography and mass spectroscopy technology. CONCLUSION: This injection drug is used in order to increase sexual desire, delay orgasm and decrease sexual inhibition and is prevalent in many studies on MSM samples. Cathinones would popularize the "slam". Harm reduction policy requires specific MSM interventions on both sexual and drug addiction networks.

Simultaneous determination of ceftaroline, daptomycin, linezolid and rifampicin concentrations in human plasma by on-line solid phase extraction coupled to high-performance liquid chromatography-tandem mass spectrometry.

Methicillin-resistant Staphylococcus aureus infection is a serious clinical problem worldwide. Ceftaroline, daptomycin, linezolid in combination with rifampicin are particularly used in this indication. To allow monitoring of these antibiotics, an on-line solid phase extraction coupled to high-performance liquid chromatography-tandem mass spectrometry assay requiring a 100 µL aliquot of human plasma has been developed. Besides, significance of 25-O-desacetylrifampicin concentrations was evaluated. Sample pre-treatment is limited to protein precipitation with methanol. After centrifugation 10 µL of supernatant are injected into the chromatographic system, which consists of an on-line solid phase extraction followed by a separation on a phenyl-hexyl column and detected by a tandem mass spectrometer. Plasma drug concentrations were determined by multiple reaction monitoring in positive ion mode, and assay performance was evaluated. 25-O-Desacetylrifampicin activity, was compared to rifampicin using a microbiological method. Sample preparation using methanol precipitation followed by solid-phase extraction yielded good recovery and ionization efficiency, with chromatographic separation achieved within 3 min per sample. Within-run and between-run precisions ranged respectively from 1.22% to 9.35% and from 1.61% to 9.36%. Lower limits of quantification were 0.04 mg/L for linezolid, 0.1mg/L for rifampicin, 0.2mg/L for ceftaroline and 0.5mg/L for daptomycin. It appears that 25-O-desacetylrifampicin displays a substantial intrinsic bactericidal activity against S. aureus. This assay provides simple, rapid, sensitive and accurate quantification of the four antibiotic drugs and one metabolite and can be routinely used to monitor drug concentration in methicillin-resistant S. aureus infected patients.

Radiosynthesis, In Vivo Biological Evaluation, and Imaging of Brain Lesions with [123I]-CLINME, a New SPECT Tracer for the Translocator Protein.

The high affinity translocator protein (TSPO) ligand 6-chloro-2-(4'-iodophenyl)-3-(N,N-methylethyl)imidazo[1,2-a]pyridine-3-acetamide (CLINME) was radiolabelled with iodine-123 and assessed for its sensitivity for the TSPO in rodents. Moreover neuroinflammatory changes on a unilateral excitotoxic lesion rat model were detected using SPECT imaging. [(123)I]-CLINME was prepared in 70-80% radiochemical yield. The uptake of [(123)I]-CLINME was evaluated in rats by biodistribution, competition, and metabolite studies. The unilateral excitotoxic lesion was performed by injection of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid unilaterally into the striatum. The striatum lesion was confirmed and correlated with TSPO expression in astrocytes and activated microglia by immunohistochemistry and autoradiography. In vivo studies with [(123)I]-CLINME indicated a biodistribution pattern consistent with TPSO distribution and the competition studies with PK11195 and Ro 5-4864 showed that [(123)I]-CLINME is selective for this site. The metabolite study showed that the extractable radioactivity was unchanged [(123)I]-CLINME in organs which expresses TSPO. SPECT/CT imaging on the unilateral excitotoxic lesion indicated that the mean ratio uptake in striatum (lesion:nonlesion) was 2.2. Moreover, TSPO changes observed by SPECT imaging were confirmed by immunofluorescence, immunochemistry, and autoradiography. These results indicated that [(123)I]-CLINME is a promising candidate for the quantification and visualization of TPSO expression in activated astroglia using SPECT.

Comparison of in vivo binding properties of the 18-kDa translocator protein (TSPO) ligands [(18)F]PBR102 and [ (18)F]PBR111 in a model of excitotoxin-induced neuroinflammation.

PURPOSE: The in vivo binding parameters of the novel imidazopyridine TSPO ligand [(18)F]PBR102 were assessed and compared with those of [(18)F]PBR111 in a rodent model of neuroinflammation. The validity of the key assumptions of the simplified reference tissue model (SRTM) for estimation of binding potential (BP) was determined, with validation against a two-tissue compartment model (2TC). METHODS: Acute neuroinflammation was assessed 7 days after unilateral stereotaxic administration of (R,S)-α-amino-3-hydroxy-5-methyl-4-isoxazolopropionique (AMPA) in anaesthetized adult Wistar rats. Anaesthetized rats were implanted with a femoral arterial cannula then injected with a low mass of [(18)F]PBR102 or [(18)F]PBR111 and dynamic images were acquired over 60 min using an INVEON PET/CT camera. Another population of rats underwent the same PET protocol after pretreatment with a presaturating mass of the same unlabelled tracer (1 mg/kg) to assess the validity of the reference region for SRTM analysis. Arterial blood was sampled during imaging, allowing pharmacokinetic determination of radiotracer concentrations. Plasma activity concentration-time curves were corrected for unchanged tracer based on metabolic characterization experiments in a separate cohort of Wistar rats. The stability of neuroinflammation in both imaging cohorts was assessed by [(125)I] CLINDE TSPO quantitative autoradiography, OX42/GFAP immunohistochemistry, Fluoro-Jade C histology, and elemental mapping using microparticle-induced x-ray emission spectroscopy. The BP of each ligand were assessed in the two cohorts of lesioned animals using both SRTM and a 2TC with arterial parent compound concentration, coupled with the results from the presaturation cohort for comparison and validation of the SRTM. RESULTS: The BPs of [(18)F]PBR102 [(18)F]PBR111 were equivalent, with improved signal-to-noise ratio and sensitivity compared with [(11)C]PK11195. The presaturation study showed differences in the volume of distribution between the ipsilateral striatum and the striatum contralateral to the injury (0.7) indicating that an assumption of the SRTM was not met. The modelling indicated that the BPs were consistent for both ligands. Between the SRTM and 2TC model, the BPs were highly correlated, but there was a bias in BP. CONCLUSION: [(18)F]PBR102 and [(18)F]PBR111 have equivalent binding properties in vivo, displaying significantly greater BPs with lower signal-to-noise ratio than [(11)C]PK11195. While an assumption of the SRTM was not met, this modelling approach was validated against 2TC modelling for both ligands, facilitating future use in longitudinal PET imaging of neuroinflammation.

Leaf wounding or simulated herbivory in young N. attenuata plants reduces carbon delivery to roots and root tips.

MAIN CONCLUSION: In Nicotiana attenuata seedlings, simulated herbivo ry by the specialist Manduca sexta decreases root growth and partitioning of recent photoassimilates to roots in contrast to increased partitioning reported for older plants. Root elongation rate in Nicotiana attenuata has been shown to decrease after leaf herbivory, despite reports of an increased proportion of recently mobilized photoassimilate being delivered towards the root system in many species after similar treatments. To study this apparent contradiction, we measured the distribution of recent photoassimilate within root tissues after wounding or simulated herbivory of N. attenuata leaves. We found no contradiction: herbivory reduced carbon delivery to root tips. However, the speed of phloem transport in both shoot and root, and the delivery of recently assimilated carbon to the entire root system, declined after wounding or simulated herbivory, in contrast with the often-reported increase in root partitioning. We conclude that the herbivory response in N. attenuata seedlings is to favor the shoot and not bunker carbon in the root system.

A liquid chromatography-tandem mass spectrometry assay for quantification of rilpivirine and dolutegravir in human plasma.

A liquid chromatography-tandem mass spectrometry assay requiring a 100µL aliquot of human plasma for simultaneous determination of rilpivirine, a second generation non-nucleoside reverse transcriptase inhibitors of HIV and dolutegravir, a novel integrase stand transfer inhibitors of HIV concentrations has been developed. Sample pre-treatment is limited to protein precipitation with a mixture of methanol and zinc sulfate. After centrifugation the supernatant is injected in the chromatographic system, which consists of on-line solid phase extraction followed by separation on a phenyl-hexyl column. This 2.5min method, with its simple sample preparation provides sensitive (the limit of quantitation is 25ng/mL for each compound), accurate and precise (the intra-day and inter-day imprecision and inaccuracy are lower than 15%) quantification of the plasma concentration of these drugs and can be used for therapeutic drug monitoring in patients infected with HIV.

Increased Th17/Treg ratio in chronic liver GVHD.

The contribution of Th17 cells to chronic GVHD (cGVHD) has been demonstrated in cGVHD mouse models. However, their contribution to human liver cGVHD remains unclear. We evaluated Th17 cells in biopsies from a cohort of 17 patients with liver cGVHD. We observed a significant increase in Th17 cells in the liver of patients with cGVHD, as demonstrated by an increase in CCR6+, CD161+ and RORγt+ T cells (P=0.03, P=0.0001 and P=0.03, respectively). We also assessed the presence of Th1 and regulatory (Treg) T cells: the numbers of Th1 and Treg cells were very low, with no difference between the two groups (P=0.88 and P=0.12, respectively). Furthermore, Th17/Th1 and Th17/Treg ratios were significantly increased in the liver of patients with liver cGVHD (P=0.005 and P=0.002, respectively). This study provides evidence for an infiltration by Th17 cells in the liver of patients with cGVHD and an increased Th17/Treg ratio, suggesting a defect in the regulatory mechanism driven by Treg cells or an inappropriate activation of effectors cells, especially Th17 cells, or both mechanisms, in human liver cGVHD.

NEMA NU 4-2008 validation and applications of the PET-SORTEO Monte Carlo simulations platform for the geometry of the Inveon PET preclinical scanner.

Monte Carlo-based simulation of positron emission tomography (PET) data plays a key role in the design and optimization of data correction and processing methods. Our first aim was to adapt and configure the PET-SORTEO Monte Carlo simulation program for the geometry of the widely distributed Inveon PET preclinical scanner manufactured by Siemens Preclinical Solutions. The validation was carried out against actual measurements performed on the Inveon PET scanner at the Australian Nuclear Science and Technology Organisation in Australia and at the Brain & Mind Research Institute and by strictly following the NEMA NU 4-2008 standard. The comparison of simulated and experimental performance measurements included spatial resolution, sensitivity, scatter fraction and count rates, image quality and Derenzo phantom studies. Results showed that PET-SORTEO reliably reproduces the performances of this Inveon preclinical system. In addition, imaging studies showed that the PET-SORTEO simulation program provides raw data for the Inveon scanner that can be fully corrected and reconstructed using the same programs as for the actual data. All correction techniques (attenuation, scatter, randoms, dead-time, and normalization) can be applied on the simulated data leading to fully quantitative reconstructed images. In the second part of the study, we demonstrated its ability to generate fast and realistic biological studies. PET-SORTEO is a workable and reliable tool that can be used, in a classical way, to validate and/or optimize a single PET data processing step such as a reconstruction method. However, we demonstrated that by combining a realistic simulated biological study ([(11)C]Raclopride here) involving different condition groups, simulation allows one also to assess and optimize the data correction, reconstruction and data processing line flow as a whole, specifically for each biological study, which is our ultimate intent.