How Do Plants Defend Themselves From Root-Eating Creatures?

The belowground world is full of creatures that depend on plants as a food source. Belowground plant eaters, or herbivores, feed on roots and can cause considerable damage to plants. Roots are very important because they help plants take up water and nutrients from the soil. These are important resources that plants need for growth. To protect their roots, plants produce chemical defenses. The production of these defenses is costly because nutrients and energy used to make defenses cannot be used for growth or the production of flowers and seeds. Plants, therefore, must be efficient with their defenses. Scientists are very interested in understanding how plants defend themselves efficiently, because this can help us to develop more environmentally friendly ways of growing fruits and vegetables. In this article, we explain how plants defend themselves efficiently, and how plant defenses affect herbivores in the soil

Pharmacokinetics and sputum penetration of azithromycin during once weekly dosing in cystic fibrosis patients

In this study we examined pharmacokinetics, systemic exposure and sputum penetration of azithromycin (AZM) in CF patients on chronic daily AZM therapy after changing to a once weekly dosing scheme. Eight adult CF patients using AZM 500 mg/day were changed to a once weekly dose of 1000 mg during 3 months. Once per month sputum and blood samples were collected. AZM was quantified in blood plasma and polymorphonuclear neutrophils. The cumulative weekly dose was reduced with a factor of 3.5 (7x500 mg vs. 1x1000 mg weekly). This led to a reduction in area under the curve (AUC+/-S.D.) with a factor of 2.5+/-0.8 in plasma, 2.8+/-0.9 in blood, 2.2+/-1.1 in PMNNs and to a reduction in average sputum concentration with a factor of 3.0 (+/-1.5). At 1000 mg once weekly reduced but still substantial concentrations were achieved in PMNNs and in sputum. Although not significant, a tendency towards less than linear reduction was found. In order to calculate and propose an optimal dosing scheme we need to establish a relation between exposure levels and clinical efficacy

The potential impact of CT-MRI matching on tumor volume delineation in advanced head and neck cancer

To study the potential impact of the combined use of CT and MRI scans on the Gross Tumor Volume (GTV) estimation and interobserver variation. Four observers outlined the GTV in six patients with advanced head and neck cancer on CT, axial MRI, and coronal or sagittal MRI. The MRI scans were subsequently matched to the CT scan. The interobserver and interscan set variation were assessed in three dimensions. The mean CT derived volume was a factor of 1.3 larger than the mean axial MRI volume. The range in volumes was larger for the CT than for the axial MRI volumes in five of the six cases. The ratio of the scan set common (i.e., the volume common to all GTVs) and the scan set encompassing volume (i.e., the smallest volume encompassing all GTVs) was closer to one in MRI (0.3-0.6) than in CT (0.1-0.5). The rest volumes (i.e., the volume defined by one observer as GTV in one data set but not in the other data set) were never zero for CT vs. MRI nor for MRI vs. CT. In two cases the craniocaudal border was poorly recognized on the axial MRI but could be delineated with a good agreement between the observers in the coronal/sagittal MRI. MRI-derived GTVs are smaller and have less interobserver variation than CT-derived GTVs. CT and MRI are complementary in delineating the GTV. A coronal or sagittal MRI adds to a better GTV definition in the craniocaudal directio

Flucloxacillin decreases tacrolimus blood trough levels:a single-center retrospective cohort study

PURPOSE: Tacrolimus and everolimus are widely used to prevent allograft rejection. Both are metabolized by the hepatic cytochrome P450 (CYP) enzyme CYP3A4 and are substrate for P-glycoprotein (P-gp). Drugs influencing the activity or expression of CYP enzymes and P-gp can cause clinically relevant changes in the metabolism of immunosuppressants. Several case reports have reported that flucloxacillin appeared to decrease levels of drugs metabolized by CYP3A4 and P-gp. The magnitude of this decrease has not been reported yet. METHODS: In this single-center retrospective cohort study, we compared the tacrolimus and everolimus blood trough levels (corrected for the dose) before, during, and after flucloxacillin treatment in eleven transplant patients (tacrolimus n = 11 patients, everolimus n = 1 patient, flucloxacillin n = 11 patients). RESULTS: The median tacrolimus blood trough level decreased by 37.5% (interquartile range, IQR 26.4-49.7%) during flucloxacillin treatment. After discontinuation of flucloxacillin, the tacrolimus blood trough levels increased by a median of 33.7% (IQR 22.5-51.4%). A Wilcoxon signed-rank test showed statistically significantly lower tacrolimus trough levels during treatment with flucloxacillin compared with before (p = 0.009) and after flucloxacillin treatment (p = 0.010). In the only available case with concomitant everolimus and flucloxacillin treatment, the same pattern was observed. CONCLUSIONS: Flucloxacillin decreases tacrolimus trough levels, possibly through a CYP3A4 and/or P-gp-inducing effect. It is strongly recommended to closely monitor tacrolimus and everolimus trough levels during flucloxacillin treatment and up to 2 weeks after discontinuation of flucloxacillin

Ultra-high throughput dual channel liquid chromatography with tandem mass spectrometry for quantification of four immunosuppressants in whole blood for therapeutic drug monitoring

Liquid chromatography with tandem mass spectrometry (LC-MS/MS) is the golden standard for immunosuppressants analyses, where optimising throughput by parallel chromatography can reduce costs and turnaround time. We aimed to double our system throughput using a dual LC-MS/MS setup. Therefore, two independent UPLC systems were hyphenated to one triple quadrupole MS, with staggered injections from one autosampler on alternating columns. The method simultaneously measured the analytes tacrolimus, sirolimus, everolimus, and cyclosporin A in whole blood using isotope dilution, with a run time of 1.5 min. Using the dual LC-MS/MS system, net run-to-run time improved from 2.3 to 0.98 min per injection, where throughput increased from 26 to 61 injections per hour. For Performance Qualification, 1101 clinical samples were measured on the dual LC-MS/MS system in addition to the standard system, during a period of one month, and the results were compared using Passing Bablok regression and Bland Altman analysis. There was excellent agreement for all four analytes, with regression slopes of 0.98-1.02x and intercepts of -0.11-0.88 µg/L. Minor bias was demonstrated between the systems with mean differences from -0.93 to 1.43%. In conclusion, the throughput was doubled and idle MS time was reduced with good agreement to the standard system. Currently, the method is applied for clinical routine with frequent peak intensities of &gt;180 injections per day.</p

Reducing the risk of non-sterility of aseptic handling in hospital pharmacies, part A:Risk assessment

OBJECTIVES: To determine prospectively the sources of risk of non-sterility during aseptic handling and to quantify the risks of each of these sources. METHODS: A risk assessment (RA) of non-sterility according to Failure Mode and Effect Analysis was executed by a multidisciplinary team of (hospital) pharmacists and technicians, a consultant experienced in aseptic processing and an independent facilitator. The team determined the sources of risk of non-sterility, a 5 point scale for severity, occurrence and detection, and risk acceptance levels. Input about general applied risk reduction was collected by audits in 10 hospital pharmacies. The results of these audits were used for determining the remaining risks. The results, as well as scientific information and the experience of the team members, was used to determine scores for severity, occurrence and detection. RESULTS: Multiplying the scores for severity, occurrence and detection results in the risk prioritisation number (RPN) which is a relative value of the remaining risks of non-sterility for each source. Incorrect disinfection techniques of non-sterile materials and the chances of touching critical spots were estimated as the greatest risks. The risk of non-sterility via the airborne route was low. RPN values were helpful in prioritising measures for additional risk reduction (this will be described in an accompanying article). CONCLUSION: The RA, described here, was a systematic survey related to all sources of risk of non-sterility during aseptic handling. The determined RPN values were helpful in prioritising measures for additional risk reduction

Reducing the risk of non-sterility of aseptic handling in hospital pharmacies, part C:Applying risk assessment and risk control in practice

OBJECTIVES: To describe the application of the model described in part A and part B of this series of articles for risk assessment (RA) and risk control (RC) of non-sterility during aseptic handling. The model was applied in nine hospital pharmacies.METHODS: The starting point was an audit of each hospital pharmacy. The determined risk reduction and remaining risks were entered into a risk assessment model. The corresponding risk prioritisation numbers (RPNs) for each source of risk were calculated and these values were summed up to a cumulative RPN. Subsequently, all hospital pharmacies started an improvement programme, using the risk assessment as input. Results of aseptic process simulation (APS) and microbiological monitoring (MM) were also collected. The participants were informed about their progress of risk reduction and results of APS and MM during the study period. At the end of the study (about 4 years after the start), a final assessment was executed by using a checklist with risk reducing measures for each source of risk. Additional risk reduction and remaining risks were put in an RA and RC template and corresponding RPN values and a new cumulative RPN were determined.RESULTS: At the start of the study differences in cumulative RPN values were relatively small (from 630 to 825). At the end they were relatively great (from 230 to 725), which illustrates a different sense of urgency for reducing the risk of non-sterility. Of all the risk reducing measures, a yearly audit of all operators had the greatest impact on reducing the risk of non-sterility. Except for glove prints, there was no correlation between process improvement (lower cumulative RPN) and results of microbiological controls.CONCLUSION: A systematic and science-based reduction of the risks of non-sterility can be done by using a checklist with risk reducing measures and an RA &amp; RC template. Prospectively, the relevance of each risk reducing measure can be demonstrated by RPN calculations. Microbiological controls are an important part of the overall assurance of product quality. However, the results are less useful for assessing the risk of non-sterility.</p

CD20 and CD40 mediated mitogenic responses in B-lineage acute lymphoblastic leukaemia

Activation of CD20, a cross-membrane ion channel, induces cell cycle progression from G0 to G1 in B lymphocytes. Subsequent activation of CD40, a membrane receptor of the nerve growth factor receptor superfamily, transits the B cells to the S phase. CD40 may also act synergistically in combination with IL-4 (B lymphocytes) or IL-3/IL-7 (B-cell precursors). We investigated the proliferative responses of B-lineage acute lymphoblastic leukaemia (ALL) cells to CD20/CD40 activation. In 18/56 ALL cases, CD20 activation resulted in significant increases in DNA synthesis. Similar, although more moderate, effects were seen of activation of CD40 in 10/44 cases. Responses to CD20 or CD40 activation were independent of co-stimulation with IL-3, IL-4 or IL-7, and various cocktails of the different growth stimuli did not act synergistically