Calorimetric determination of polymerization enthalpy for bacterial flagellin (Salmonella)

The polymerization of bacterial flagellin protein (Salmonella strain SJ814) into flagellar filaments has been found by direct calorimetric measurement to be $\text{exothermic}$ at 25° in .15M KCl, pH 6.8 with a ΔH of ?12.7 ± 0.6 kcal per mole of monomer polymerized. The calorimetric result at 25° contrasts sharply with the endothermic ΔH of +38 kcal/mole inferred from temperature dependence of the critical monomer concentration near 40°C. Comparison between these two values implies that unless a different mechanism of polymerization prevails at the two temperatures the heat capacity change for flagellin polymerization may be as large as 3.3 kcal/mole deg.     

Effect of monomer treatment and polymerisation methods on the bond strength of resin teeth to denture base material

Background: The fracture between acrylic denture base material and artificial teeth is a common clinical occurrence in dental prosthodontic practice. Objective: To evaluate the bond strength between acrylic resins and resin denture teeth when submitted by two protocols of monomer liquid application on the tooth surface and using different polymerisation methods. Material and methods: Microwave‐polymerised (Onda‐Cryl), heat‐polymerised (Clássico) and autopolymerising (Jet) acrylic resins and a brand of resin denture teeth (Biotone) were used. The acrylic resins were polymerised according to the cycles: (A) microwave – fast cycle, Onda‐Cryl; (B) microwave – long cycle, Onda‐Cryl; (C) microwave – manufacturer’s cycle, Onda‐Cryl; (T) water bath – long cycle, Clássico and (Q) bench polymerisation cycle, Jet. Thirty specimens were prepared for each polymerisation method; 10 were packed with acrylic resin after 60 s of monomer liquid application on the tooth surface, 10 after 180 s and 10 without any monomer liquid application. For the purpose of the study, a shear test was used. anova and Tukey tests were performed to identify significant differences (α = 0.05). Results: The highest bond strength values were found for monomer surface treatments, regardless of the polymerisation cycles. The highest significant values were found for cycles B (15.4 ± 1.8 MPa), C (11.9 ± 4.9 MPa) and T (15.4 ± 2.6 MPa) for non‐treated and 60 s methylmethacrylate treated groups. Comparing the monomer liquid treatment, they did not differ significantly (p > 0.05), except for cycle A (p < 0.05). Conclusion: Chemical treatment using monomer on the tooth surface prior to the acrylic resin packing improved the bond strength between resin denture tooth and acrylic resin, regardless of monomer liquid treatment protocols. The microwavable resin, polymerised by fast cycle and autopolymerising resin should be avoided for processing denture and denture repairs, respectively.     

Measuring the dose in bone for spine stereotactic body radiotherapy

PurposeCurrent quality assurance of radiotherapy involving bony regions generally utilises homogeneous phantoms and dose calculations, ignoring the challenges of heterogeneities with dosimetry problems likely occurring around bone. Anthropomorphic phantoms with synthetic bony materials enable realistic end-to-end testing in clinical scenarios. This work reports on measurements and calculated corrections required to directly report dose in bony materials in the context of comprehensive end-to-end dosimetry audit measurements (63 plans, 6 planning systems).Materials and methodsRadiochromic film and microDiamond measurements were performed in an anthropomorphic spine phantom containing bone equivalent materials. Medium dependent correction factors, k_med, were established using 6 MV and 10 MV Linear Accelerator Monte Carlo simulations to account for the detectors being calibrated in water, but measuring in regions of bony material. Both cortical and trabecular bony material were investigated for verification of dose calculations in dose-to-medium (D_m,m) and dose-to-water (D_w,w) scenarios.ResultsFor D_m,m calculations, modelled correction factors for cortical and trabecular bone in film measurements, and for trabecular bone in microDiamond measurements were 0.875(±0.1%), 0.953(±0.3%) and 0.962(±0.4%), respectively. For D_w,w calculations, the corrections were 0.920(±0.1%), 0.982(±0.3%) and 0.993(±0.4%), respectively. In the audit, application of the correction factors improves the mean agreement between treatment plans and measured microDiamond dose from −2.4%(±3.9%) to 0.4%(±3.7%).ConclusionMonte Carlo simulations provide a method for correcting the dose measured in bony materials allowing more accurate comparison with treatment planning system doses. In verification measurements, algorithm specific correction factors should be applied to account for variations in bony material for calculations based on D_m,m and D_w,w.     

Quantification of residual dose estimation error on log file-based patient dose calculation

PurposeThe log file-based patient dose estimation includes a residual dose estimation error caused by leaf miscalibration, which cannot be reflected on the estimated dose. The purpose of this study is to determine this residual dose estimation error.Methods and materialsModified log files for seven head-and-neck and prostate volumetric modulated arc therapy (VMAT) plans simulating leaf miscalibration were generated by shifting both leaf banks (systematic leaf gap errors: ±2.0, ±1.0, and ±0.5 mm in opposite directions and systematic leaf shifts: ±1.0 mm in the same direction) using MATLAB-based (MathWorks, Natick, MA) in-house software. The generated modified and non-modified log files were imported back into the treatment planning system and recalculated. Subsequently, the generalized equivalent uniform dose (gEUD) was quantified for the definition of the planning target volume (PTV) and organs at risks.ResultsFor MLC leaves calibrated within ±0.5 mm, the quantified residual dose estimation errors that obtained from the slope of the linear regression of gEUD changes between non- and modified log file doses per leaf gap are in head-and-neck plans 1.32 ± 0.27% and 0.82 ± 0.17 Gy for PTV and spinal cord, respectively, and in prostate plans 1.22 ± 0.36%, 0.95 ± 0.14 Gy, and 0.45 ± 0.08 Gy for PTV, rectum, and bladder, respectively.ConclusionsIn this work, we determine the residual dose estimation errors for VMAT delivery using the log file-based patient dose calculation according to the MLC calibration accuracy.     

Can different Catphan phantoms be used in a multi-centre audit of radiotherapy CT image quality?

PurposeTo determine the variation between Catphan image quality CT phantoms, specifically for use in a future multi-centre image quality audit.Method14 Catphan phantoms (models 503, 504 and 604) were scanned on a Canon Aquilion Prime CT scanner using a single scan protocol. Measurements were made of noise in the uniformity section, visibility of low contrast targets and contrast, x-ray attenuation and CT number for 5 materials in the sensitometry section. Scans were also acquired using one phantom and varying reconstruction field of view, image slice thickness, effective tube-current-time product and iterative reconstruction settings to determine how the degree of inter-phantom variability compared with the magnitude of changes from scan parameter alteration.ResultsAcross all phantoms the mean CT value in the uniformity section was 7.0 (SD 0.9) range: 4.9–8.1 HU. For the different materials the CT numbers were air: −1004 ± 5, Polymethylpentene: −190 ± 2, Polystyrene: −42 ± 2, Delrin: 321 ± 5 and Teflon: 898 ± 8 HU. Consistency of low contrast targets through visual scoring was good. Measured contrast was lower (p < 0.001) with more variability for 504 versus 604 models. All phantoms produced identical tube current settings with x-ray tube current modulation, indicating no x-ray attenuation differences. The degree of change in image quality metrics between phantoms was small compared with results when scan parameters were varied.ConclusionCatphan phantoms model 604 showed minimal differences and will be used for multi-centre inter-comparison work, with the consistency between phantoms appropriate for measuring possible variations in image quality.     

El lavado de la aguja aumenta la rentabilidad diagnóstica de la punción-aspiración con aguja fina de tiroides

Background and objectiveNodular thyroid disease is a common condition in our clinical practice, and fine needle aspiration biopsy (FNAB) is the diagnostic procedure of choice. Its main limitation is the number of non-diagnostic samples. Since the Bethesda criteria were implemented in 2007 (a consensus document on the morphologic criteria and diagnostic terminology for interpretation of thyroid cytological samples), a higher prevalence of non-diagnostic FNAB was shown. In addition to the standard technique, we decided to collect and centrifuge the material remaining in puncture needles by washing them in a ThinPrep^® solution, and to assess the increase in the diagnostic yield of FNAB after this change.Patients and methodsSystematic sampling of 168 patients who underwent FNAB at the Nutrition and Endocrinology Department of the Xeral-Cies Hospital (Vigo, Spain) from January 2010 to November 2011. Patients were classified into 2 groups: 75 patients in whom the residual material in the needle was not collected (non-washing group) and 93 patients in whom the material was collected (washing-group). All FNABs were performed by the same endocrinologist. Data are shown as percentage (± standard error) for ordinal variables or as mean (± standard deviation) for quantitative variables. A Chi-square test was used for statistical analysis of comparisons between percentages, and a Student's t test for comparisons between quantitative variables. A value of p < 0.05 was considered statistically significant.ResultsNo significant differences were found between the groups in age, sex, plasma TSH levels or nodule size. The rate of non-diagnostic FNABs was 44% (± 0.06) in the non-washing group and 17.2% (± 0.04%) in the washing group, with a significant difference (p < 0.01).DiscussionCollection and subsequent processing of the residual material in the needle after FNAB significantly decreased the prevalence of non-diagnostic punctures in our patients. Collection of the residual material in the needle in this way is strongly recommended.     

Radiological properties of 3D printed materials in kilovoltage and megavoltage photon beams

PurposeThis study evaluates the radiological properties of different 3D printing materials for a range of photon energies, including kV and MV CT imaging and MV radiotherapy beams.MethodsThe CT values of a number of materials were measured on an Aquilion One CT scanner at 80 kVp, 120 kVp and a Tomotherapy Hi Art MVCT imaging beam. Attenuation of the materials in a 6 MV radiotherapy beam was investigated.ResultsPlastic filaments printed with various infill densities have CT values of −743 ± 4, −580 ± 1 and −113 ± 3 in 120 kVp CT images which approximate the CT values of low-density lung, high-density lung and soft tissue respectively. Metal-infused plastic filaments printed with a 90% infill density have CT values of 658 ± 1 and 739 ± 6 in MVCT images which approximate the attenuation of cortical bone. The effective relative electron density RED_eff is used to describe the attenuation of a megavoltage treatment beam, taking into account effects relating to the atomic number and mass density of the material. Plastic filaments printed with a 90% infill density have RED_eff values of 1.02 ± 0.03 and 0.94 ± 0.02 which approximate the relative electron density RED of soft tissue. Printed resins have RED_eff values of 1.11 ± 0.03 and 1.09 ± 0.03 which approximate the RED of bone mineral.Conclusions3D printers can model a variety of body tissues which can be used to create phantoms useful for both imaging and dosimetric studies.     

Initial Characterization of Micafungin Pulmonary Delivery via Two Different Nebulizers and Multivariate Data Analysis of Aerosol Mass Distribution Profiles

Pharmaceutical aerosols have been targeted to the lungs for the treatment of asthma and pulmonary infectious diseases successfully. Micafungin (Astellas Pharma US, Deerfield, IL, USA) has been shown to be an effective antifungal agent when administrated intravenously. Pulmonary delivery of micafungin has not previously been reported. In the present pilot study, we characterize the performance of two nebulizers and their potential for delivering micafungin to the lungs as well as the use of multivariate data analysis for mass distribution profile comparison. The concentration of micafungin sodium increased by 21% when delivered by the Acorn II nebulizer and by 20% when delivered by the LC Plus nebulizer, respectively, from the first to the second sampling period. The Acorn II nebulizer delivered a fine particle fraction FPF_5.8 (%<5.8 μm) of 92.5 ± 0.8 and FPF_3.3 (%<3.3 μm) of 82.3 ± 2.1 during the first sampling period. For the LC Plus nebulizer, FPF_5.8 was 92.3 ± 0.1 and FPF_3.3 was 67.0 ± 0.7 during the first sampling period. The mass median aerodynamic diameter (MMAD) increased from 1.67 ± 0.05 to 1.77 ± 0.04 μm (Acorn II nebulizer) and from 2.09 ± 0.01 to 2.20 ± 0.01 μm (Pari LC Plus nebulizer) from the first to the second sampling periods. These changes in MMAD were statistically significant by paired t test. Multivariate data analysis showed that this could be explained systematically by greater drug deposition on stages with larger cutoff sizes and reduced drug deposition on stages with smaller cutoff sizes rather than multimodal deposition or other anomalies in size distribution.     

Cytotoxic activity of anti-mucin 1 chimeric antigen receptor T cells expressing PD-1-CD28 switch receptor against cholangiocarcinoma cells

Background aimsCholangiocarcinoma (CCA) is a lethal bile-duct cancer that is difficult to treat by current standard procedures. This drawback has prompted us to develop adoptive T-cell therapy for CCA, which requires an appropriate target antigen for binding of chimeric antigen receptor (CAR) T cells. Mucin 1 (MUC1), an overexpressed protein in CCA cells, is a potential target antigen for the CAR T-cell development. However, MUC1 overexpression also is associated with the upregulation of programmed death-ligand 1 (PD-L1), an immune checkpoint protein that prohibits anti-tumor functions of T cells, probably causing poor overall survival of patients with CCA.MethodsTo overcome this problem, we developed anti-MUC1-CAR T cells containing PD-1-CD28 switch receptor (SR), namely αM.CAR/SR T cells, to target MUC1 and switch on the inhibitory signal of PD-1/PD-L1 interaction to activate CD28 signaling. Our lentiviral construct contains the sequences that encode anti-MUC1-single chain variable fragment, CD137 and CD3ζ, linked with P2A, PD-1 and CD28.ResultsInitially, the upregulations of MUC1 and PD-L1 proteins were confirmed in CCA cell lines. αM.CAR and SR were co-expressed in 53.53 ± 13.89% of transduced T cells, mainly CD8⁺ T cells (85.7 ± 0.75%, P<0.0001) with the effector memory phenotype (59.22 ± 16.31%, P < 0.01). αM.CAR/SR T cells produced high levels of intracellular tumor necrosis factor-α and interferon-γ in response to the activation by CCA cells expressing MUC1, including KKU-055 (27.18 ± 4.38% and 27.33 ± 5.55%, respectively, P < 0.05) and KKU-213A (47.37 ± 12.67% and 54.55 ± 8.66%, respectively, P < 0.01). Remarkably, the cytotoxic function of αM.CAR/SR T cells against KKU-213A cells expressing PD-L1 was significantly enhanced compared with the αM.CAR T cells (70.69 ± 14.38% versus 47.15 ± 8.413%, respectively; P = 0.0301), correlated with increased granzyme B production (60.6 ± 9.89% versus 43.2 ± 8.95%, respectively; P = 0.0402). Moreover, the significantly enhanced disruption of KKU-213A spheroids by αM.CAR/SR T cells (P = 0.0027), compared with αM.CAR T cells, was also observed.ConclusionTaken together, the cytotoxic function of αM.CAR/SR T cells was enhanced over the αM.CAR T cells, which are potential to be further tested for CCA treatment.     

In situ evaluation of surface roughness and micromorphology of temporary soft denture liner materials at different time intervals

Objective

To perform an in situ evaluation of surface roughness and micromorphology of two soft liner materials for dentures at different time intervals.

Background

The surface roughness of materials may influence the adhesion of micro‐organisms and inflammation of the mucosal tissues. The in situ evaluation of surface roughness and the micromorphology of soft liner materials over the course of time may present results different from those of in vitro studies, considering the constant presence of saliva and food, the changes in temperature and the pH level in the oral cavity.

Materials and methods

Forty‐eight rectangular specimens of each of the two soft liner materials were fabricated: a silicone‐based material (Mucopren Soft) and an acrylic resin‐based material (Trusoft). The specimens were placed in the dentures of 12 participants (n = 12), and the materials were evaluated for surface roughness and micromorphology at different time intervals: 0, 7, 30 and 60 days. Roughness (Ra) was evaluated by means of a roughness tester. Surface micromorphology was evaluated by scanning electron microscopy.

Results

Analysis of variance for randomised block design and Tukey's test showed that surface roughness values were lower in the groups using the silicone‐based material at all the time intervals (P < .0001). The average surface roughness was higher at time interval 0 than at the other intervals, for both materials (P < .0001). The surface micromorphology showed that the silicone material presented a more regular and smoother surface than the acrylic resin‐based material.

Conclusion

The surface roughness of acrylic resin‐based and silicone‐based denture soft liner materials decreased after 7 days of evaluation, leading to a smoother surface over time. The silicone‐based material showed lower roughness values and a smoother surface than the acrylic resin‐based material, thereby making it preferred when selecting more appropriate material, due its tendency to promote less biofilm build‐up.     

3D-printed patient-specific pelvis phantom for dosimetry measurements for prostate stereotactic radiotherapy with dominant intraprostatic lesion boost

AimDeveloping and assessing the feasibility of using a three-dimensional (3D) printed patient-specific anthropomorphic pelvis phantom for dose calculation and verification for stereotactic ablative radiation therapy (SABR) with dose escalation to the dominant intraprostatic lesions.Material and methodsA 3D-printed pelvis phantom, including bone-mimicking material, was fabricated based on the computed tomography (CT) images of a prostate cancer patient. To compare the extent to which patient and phantom body and bones overlapped, the similarity Dice coefficient was calculated. Modular cylindrical inserts were created to encapsulate radiochromic films and ionization chamber for absolute dosimetry measurements at the location of prostate and at the boost region. Gamma analysis evaluation with 2%/2mm criteria was performed to compare treatment planning system calculations and measured dose when delivering a 10 flattening filter free (FFF) SABR plan and a 10FFF boost SABR plan.ResultsDice coefficients of 0.98 and 0.91 were measured for body and bones, respectively, demonstrating agreement between patient and phantom outlines. For the boost plans the gamma analysis yielded 97.0% of pixels passing 2%/2mm criteria and these results were supported by the chamber average dose difference of 0.47 ± 0.03%. These results were further improved when overriding the bone relative electron density: 97.3% for the 2%/2mm gamma analysis, and 0.05 ± 0.03% for the ionization chamber average dose difference.ConclusionsThe modular patient-specific 3D-printed pelvis phantom has proven to be a highly attractive and versatile tool to validate prostate SABR boost plans using multiple detectors.     

Evaluation of the Block Matching deformable registration algorithm in the field of head-and-neck adaptive radiotherapy

Background and purposeTo compare the accuracy of the Block Matching deformable registration (DIR) against rigid image registration (RIR) for head-and-neck multi-modal images CT to cone-beam CT (CBCT) registration.Material and methodsPlanning-CT and weekly CBCT of 10 patients were used for this study. Several volumes, including medullary canal (MC), thyroid cartilage (TC), hyoid bone (HB) and submandibular gland (SMG) were transposed from CT to CBCT images using either DIR or RIR. Transposed volumes were compared with the manual delineation of these volumes on every CBCT. The parameters of similarity used for analysis were: Dice Similarity Index (DSI), 95%-Hausdorff Distance (95%-HD) and difference of volumes (cc).ResultsWith DIR, the major mean difference of volumes was −1.4 cc for MC, revealing limited under-segmentation. DIR limited variability of DSI and 95%-HD. It significantly improved DSI for TC and HB and 95%-HD for all structures but SMG. With DIR, mean 95%-HD (mm) was 3.01 ± 0.80, 5.33 ± 2.51, 4.99 ± 1.69, 3.07 ± 1.31 for MC, TC, HB and SMG, respectively. With RIR, it was 3.92 ± 1.86, 6.94 ± 3.98, 6.44 ± 3.37 and 3.41 ± 2.25, respectively.ConclusionBlock Matching is a valid algorithm for deformable multi-modal CT to CBCT registration. Values of 95%-HD are useful for ongoing development of its application to the cumulative dose calculation.     

Susceptibility of <Emphasis Type="Italic">Candida</Emphasis> biofilms to histatin 5 and fluconazole

Candida-associated denture stomatitis has a high rate of recurrence. Candida biofilms formed on denture acrylic are more resistant to antifungals than planktonic yeasts. Histatins, a family of basic peptides secreted by the major salivary glands in humans, especially histatin 5, possess significant antifungal properties. We examined antifungal activities of histatin 5 against planktonic or biofilm Candida albicans and Candida glabrata. Candida biofilms were developed on poly(methyl methacrylate) discs and treated with histatin 5 (0.01–100 μM) or fluconazole (1–200 μM). The metabolic activity of the biofilms was measured by the XTT reduction assay. The fungicidal activity of histatin 5 against planktonic Candida was tested by microdilution plate assay. Biofilm and planktonic C. albicans GDH18, UTR-14 and 6122/06 were highly susceptible to histatin 5, with 50% RMA (concentration of the agent causing 50% reduction in the metabolic activity; biofilm) of 4.6 ± 2.2, 6.9 ± 3.7 and 1.7 ± 1.5 μM, and IC₅₀ (planktonic cells) of 3.0 ± 0.5, 2.6 ± 0.1 and 4.8 ± 0.5, respectively. Biofilms of C. glabrata GDH1407 and 6115/06 were less susceptible to histatin 5, with 50% RMA of 31.2 ± 4.8 and 62.5 ± 0.7 μM, respectively. Planktonic C. glabrata was insensitive to histatin 5 (IC₅₀ > 100 μM). Biofilm-associated Candida was highly resistant to fluconazole in the range 1–200 μM; e.g. at 100 μM only ~20% inhibition was observed for C. albicans, and ~30% inhibition for C. glabrata. These results indicate that histatin 5 exhibits antifungal activity against biofilms of C. albicans and C. glabrata developed on denture acrylic. C. glabrata is significantly less sensitive to histatin 5 than C. albicans.     

Pauta óptima de administración de insulina detemir en sujetos diabéticos tipo 1 con mal control metabólico

AimTo compare different administration times of insulin detemir (IDet) in patients with type 1 diabetes and poor metabolic control.Material and MethodsThis 24-week open study included 39 people with type 1 diabetes mellitus (DM) randomized to one injection of IDet before lunch (mean 14.24 ± 00.36 (± SD) h) or at bedtime (23.19 ± 0.42 h). Whenever target glycemia levels were not reached, the regimen was switched to insulin therapy with two injections (IDet-12 h). Insulin aspart was used before main meals.ResultsAt week 24, only 12.2% of patients remained in the IDet bedtime group and 30.3% in the IDet before lunch group. The remaining 57.5% joined the IDet-12 h group. There were no differences between the IDet before lunch and IDet bedtime groups. A subanalysis including the three groups demonstrated better metabolic control in the IDet before lunch group (glycosylated hemoglobin (HbA1c) 7.1 ± 0.2 vs. 7.6 ± 0.4 and 8.1 ± 0.2% in IDet before-lunch, IDet bedtime and IDet-12 h, respectively; p<0.05). An HbA1c value below 7% was achieved in 30.3% of the patients: 15.2% in the IDet before-lunch group, 3.3% in the IDet bedtime group and 12.2% in IDet-12 h group. Quality of life did not differ among treatment groups.ConclusionsOne injection of IDet administered before lunch could improve metabolic control. However, most patients required two injections of IDet.     

Characterization of a thermostable and solvent-tolerant laccase produced by Streptomyces sp. LAO

Objectives

Decaying wood samples were collected, and actinomycetes were isolated and screened for laccase production. The identity of the efficient laccase-producing isolate was confirmed by using a molecular approach. Fermentation conditions for laccase production were optimized, and laccase biochemical properties were studied.

Results

Based on the 16S rRNA gene sequencing and phylogenetic analysis, the isolate coded as HWP₃ was identified as Streptomyces sp. LAO. The time-course study showed that the isolate optimally produced laccase at 84 h with 40.58?±?2.35 U/mL activity. The optimized physicochemical conditions consisted of pH 5.0, ferulic acid (0.04%; v/v), pine back (0.2 g/L), urea (1.0 g/L), and lactose (1 g/L). Streptomyces sp. LAO laccase was optimally active at pH and temperature of 8.0 and 90 °C, respectively, with remarkable pH and thermal stability. Furthermore, the enzyme had a sufficient tolerance for organic solvents after 16 h of preincubation, with laccase activity?>?70%. Additionally, the laccase maintained considerable residual activity after pretreatment with 100 mM of chemical agents, including sodium dodecyl sulphate (69.93?±?0.89%), ethylenediaminetetraacetic acid (93.1?±?7.85%), NaN₃ (96.28?±?3.34%) and urea (106.03?±?10.72%).

Conclusion

The laccase's pH and thermal stability; and robust catalytic efficiency in the presence of organic solvents suggest its industrial and biotechnological application potentials for the sustainable development of green chemistry.

     

Assessment of daily dose accumulation for robustly optimized intensity modulated proton therapy treatment of prostate cancer

PurposeTo implement a daily CBCT based dose accumulation technique in order to assess ideal robust optimization (RO) parameters for IMPT treatment of prostate cancer.MethodsTen prostate cancer patients previously treated with VMAT and having daily CBCT were included. First, RO-IMPT plans were created with ± 3 mm and ± 5 mm patient setup and ± 3% proton range uncertainties, respectively. Second, the planning CT (pCT) was deformably registered to the CBCT to create a synthetic CT (sCT). Both daily and weekly sampling strategies were employed to determine optimal dose accumulation frequency. Doses were recalculated on sCTs for both ± 3 mm/±3% and ± 5 mm/±3% uncertainties and were accumulated back to the pCT. Accumulated doses generated from ± 3 mm/±3% and ± 5 mm/±3% RO-IMPT plans were evaluated using the clinical dose volume constraints for CTV, bladder, and rectum.ResultsDaily accumulated dose based on both ± 3mm/±3% and ±5 mm/±3% uncertainties for RO-IMPT plans resulted in satisfactory CTV coverage (RO-IMPT_3mm/3% CTV_V95 = 99.01 ± 0.87% vs. RO-IMPT_5mm/3% CTV_V95 = 99.81 ± 0.2%, P = 0.002). However, the accumulated dose based on ± 3 mm/3% RO-IMPT plans consistently provided greater OAR sparing than ±5 mm/±3% RO-IMPT plans (RO-IMPT_3mm/3% rectum_V65Gy = 2.93 ± 2.39% vs. RO-IMPT_5mm/3% rectum_V65Gy = 4.38 ± 3%, P < 0.01; RO-IMPT_3mm/3% bladder_V65Gy = 5.2 ± 7.12% vs. RO-IMPT_5mm/3% bladder_V65Gy = 7.12 ± 9.59%, P < 0.01). The gamma analysis showed high dosimetric agreement between weekly and daily accumulated dose distributions.ConclusionsThis study demonstrated that for RO-IMPT optimization, ±3mm/±3% uncertainty is sufficient to create plans that meet desired CTV coverage while achieving superior sparing to OARs when compared with ± 5 mm/±3% uncertainty. Furthermore, weekly dose accumulation can accurately estimate the overall dose delivered to prostate cancer patients.     

Cytotoxic effects of stem bark extracts and pure compounds from Margaritaria discoidea on human ovarian cancer cell lines

Margaritaria discoidea (Baill.) G. L. Webster (Euphorbiaceae) is a well-known medicinal plant in Africa used for the treatment of various diseases. So far, no cytotoxic effects of plant extracts on cancer cell lines have been reported.Aim of the studyTo evaluate the cytotoxicity against human ovarian cancer cells of extracts of M. discoidea and characterize the major bioactive compounds.MethodsBoth organic and aqueous extracts of this plant were obtained by maceration. The sulforhodamine B cell proliferation assay was used for evaluation of their cytotoxic activities and the potential bioactive compounds were characterized by gas chromatography–mass spectrometry.ResultsThe organic extract of M. discoidea showed stronger cytotoxicity than the aqueous extract with IC₅₀ values of 14.4 ± 3.0, 14.2 ± 1.2 and 34.7 ± 0.5 µg/ml on OVCAR-8, A2780 and cisplatin-resistant A2780cis ovarian cancer cells, respectively. The organic extract was further subjected to bioassay-guided fractionation by partitioning with n-hexane, ethyl acetate, and n-butanol in water. The ethyl acetate fraction was the most potent on the three ovarian cancer cell lines. A GC–MS analysis of trimethylsilyl derivatives of this fraction indicated the presence of phenolic compounds such as gallic acid and the alkaloid securinine. The IC₅₀ values of these two compounds were determined to be in the range of 3–16 µM, which indicated that they could contribute to the cytotoxic activity of the extract of M. discoidea.ConclusionsThis study has evaluated the cytotoxicity of stem bark extracts of M. discoidea against ovarian cancer cells and provided a basis of further development of this plant for the treatment of ovarian cancer.     

Near real-time magnetic particle imaging for visual assessment of vascular stenosis in a phantom model

PurposeThis study aimed to investigate the potential of magnetic particle imaging (MPI) to quantify artificial stenoses in vessel phantoms in near real-time.MethodsCustom-made stenosis phantoms with different degrees of stenosis (0%, 25%, 50%, 75%, and 100%; length 40 mm, inner diameter 8 mm, Polyoxymethylene) were filled with diluted Ferucarbotran (superparamagnetic iron-oxide nanoparticle (SPION) tracer agent, 500 mmol (Fe)/l). A traveling wave MPI scanner (spatial resolution ~ 2 mm, gradient strength ~ 1.5 T/m, field of view: 65 mm length and 29 mm diameter, frequencies f₁ = 1050 Hz and f₂ = 12150 Hz) was used to acquire images of the phantoms (200 ms total acquisition time per image, 10 averages). Standardized grey scaling was used for comparability. All measured stenoses (n = 80) were graded manually using a dedicated software tool.ResultsMPI allowed for accurate visualization of stenoses at a frame rate of 5 frames per second. Less severe stenoses were detected more precisely than higher-grade stenoses and came with smaller standard deviations. In particular, the 0%, 25%, 50%, 75%, and 100% stenosis phantom were measured as 3.7 ± 2.7% (mean ± standard deviation), 18.6 ± 1.8%, 52.8 ± 3.7%, 77.8 ± 14.8% and 100 ± 0%. Geometrical distortions occurred around the center of the high-grade stenosis and led to higher standard deviations compared to lower grade stenoses. In the frame of this study the MPI signal depended linearly on the SPION concentration down to 0.05 mmol (Fe)/l.ConclusionNear real-time MPI accurately visualized and quantified different stenosis grades in vascular phantoms.     

Clinical Use of Liraglutide in Type 2 Diabetes and its Effects on Cardiovascular Risk Factors

ObjectiveTo assess whether liraglutide, a glucagonlike peptide-1 receptor agonist, has cardioprotective properties in addition to its glycemic effects.MethodsWe performed a retrospective analysis of medical records of 110 obese patients with type 2 diabetes mellitus treated with liraglutide for at least 6 months between March 2010 and April 2011 at our tertiary care referral center. The variables analyzed were body mass index, hemoglobin A_1c (A1C), systolic blood pressure (SBP), plasma C-reactive protein (CRP) concentrations, and serum lipids.ResultsIn our overall study cohort, we noted a reduction in mean weight from 120 ± 5 kg to 115 ± 3 kg and a decrease in mean A1C from 7.8% ± 0.6% to 7.2% ± 0.2%. The mean triglyceride concentration decreased from 173 ± 19 mg/dL to 151 ± 15 mg/dL, the mean SBP was reduced from 132 ± 6 mm Hg to 125 ± 4 mm Hg, and the mean CRP concentration declined from 4.7 ± 0.8 mg/L to 3.2 ± 0.4 mg/L after treatment with liraglutide for a minimal duration of 6 months and a mean duration of 7.5 months (for all the foregoing changes, P < .05).These variables decreased whether these patients were previously treated with orally administered hypoglycemic agents alone or in combination with insulin or exenatide.ConclusionOur findings in a clinical practice show that liraglutide is a potent antidiabetes drug, whether given in combination with orally administered agents or insulin or as a substitution for exenatide. It lowers body weight, A1C levels, SBP, and CRP and triglyceride concentrations. (Endocr Pract. 2012;18:140-145)     

Influencia del inmunoensayo empleado en la determinación de vitamina D sérica

IntroductionSerum 25-hydroxyvitamin D [25(OH)D] levels are the best indicator of vitamin D levels in the body. Precision, reproducibility, and lack of standardization are the main problems in such measurements. The aim of this study was to compare the 25(OH)D levels measured using Elecsys Vitamin D Total (Roche) and ADVIA Centaur Vitamin D Total (Siemens).Material and methods25(OH)D levels were tested in 166 patients using both methods. Patients were subsequently divided into two groups: a «supplemented group» consisting of patients receiving vitamin D supplements, and an «untreated group» consisting of the rest of patients.Results25(OH)D mean levels measured by the Roche and Siemens methods in the overall group were 33.6 ± 16.0 and 19.8 ± 12.4 ng/mL respectively. 54.2% of patients were receiving vitamin D supplements. In this group, mean 25(OH)D levels measured by the Roche and Siemens methods were 40.6 ± 14.5 and 25.4 ± 13.1 ng/mL respectively. In the untreated group, the respective values were 24.9 ± 13.2 and 12.8 ± 6.6 ng/mL. Prevalence of vitamin D deficiency (serum 25(OH)D levels less than 20 ng/mL) was higher in samples analyzed using the Siemens method (60.2%) as compared to those tested using the Roche method (23.5%).ConclusionThe assays evaluated are not comparable to each other. Laboratory specialists should inform clinicians of the features of the method used for measuring 25(OH)D because this will have a direct impact on interpretation of the results and medical decisions.