Radiolabeling and Preliminary Evaluation of Ga-68 Labeled NODAGA-Ubiquicidin Fragments for Prospective Infection Imaging

Purpose

The present work was aimed at the development of prospective positron emission tomography (PET) agents for infection imaging. Towards this aim, ubiquicidin (UBI) fragments conjugated with the macrocyclic NODAGA chelator were radiolabeled with Ga-68 and evaluated.

Procedures

Conformations of custom synthesized NODAGA-UBI (29–41) and NODAGA-UBI (31–38) conjugates were compared with UBI (29–41) by circular dichroism (CD) spectroscopy. Optimization of labeling of NODAGA conjugates of UBI peptides with Ga-68 was performed and quality control analysis was carried out by chromatography techniques. In vitro uptake of [⁶⁸Ga] NODAGA-UBI (29–41) and [⁶⁸Ga]NODAGA-UBI (31–38) was studied in Staphylococcus aureus cells. In vivo distribution of [⁶⁸Ga]GaCl₃ and [⁶⁸Ga]NODAGA-UBI complexes was performed in normal Swiss mice.

Results

Conformations of NODAGA-UBI (29–41) and NODAGA-UBI (31–38) conjugates were found to be similar to UBI (29–41). NODAGA-UBI conjugates could be consistently labeled with Ga-68 in high radiochemical yields (>95 %) with high radiochemical purity (>95 %). [⁶⁸Ga]NODAGA-UBI (29–41) and [⁶⁸Ga]NODAGA-UBI (31–38) complexes showed retention time of 14 and 14.5 min, respectively, by HPLC radiochromatogram. Specific uptake of [⁶⁸Ga]NODAGA-UBI fragments was observed in S.aureus cells. Greater than 64 % of the injected dose was cleared via the renal route at 1 h post injection, and no significant uptake in vital organs of mice was observed with both the agents.

Conclusion

This is the first report on Ga-68 labeled NODAGA-UBI fragments for infection imaging and the agents hold tremendous prospect in PET imaging.

     

<Emphasis Type="Italic">In Vitro</Emphasis> and <Emphasis Type="Italic">In Vivo</Emphasis> Comparison of Selected Ga-68 and Zr-89 Labelled Siderophores

Purpose

Some [⁶⁸Ga]siderophores show promise in specific and sensitive imaging of infection. Here, we compare the in vitro and in vivo behaviour of selected Ga-68 and Zr-89 labelled siderophores.

Procedures

Radiolabelling was performed in HEPES or sodium acetate buffer systems. Radiochemical purity of labelled siderophores was determined using chromatography. Partition coefficients, in vitro stability and protein binding affinities were determined. Ex vivo biodistribution and animal imaging was studied in mice.

Results

Certain differences among studied siderophores were observed in labelling efficiency. Protein binding and stability tests showed highest stabilities and lowest protein binding affinities for Ga-68 and [⁸⁹Zr]triacetylfusarinine C (TAFC). All studied Ga-68 and [⁸⁹Zr]siderophores exhibited a similar biodistribution and pharmacokinetics in mice with the exception of [⁸⁹Zr]ferrioxamine E (FOXE).

Conclusions

Zr-89 and [⁶⁸Ga]siderophores showed analogous in vitro and in vivo behaviour. Tested [⁸⁹Zr]siderophores could be applied for longitudinal positron emission tomography (PET) studies of fungal infections and especially TAFC for the development of novel bioconjugates.

     

Tumor Targeting <Emphasis Type="Italic">via</Emphasis> Sialic Acid: [<Superscript>68</Superscript>Ga]DOTA-en-pba as a New Tool for Molecular Imaging of Cancer with PET

Purpose

The aim of this study was to demonstrate the potential of Ga-68-labeled macrocycle (DOTA-en-pba) conjugated with phenylboronic vector for tumor recognition by positron emission tomography (PET), based on targeting of the overexpressed sialic acid (Sia).

Procedures

The imaging reporter DOTA-en-pba was synthesized and labeled with Ga-68 at high efficiency. Cell binding assay on Mel-C and B16-F10 melanoma cells was used to evaluate melanin production and Sia overexpression to determine the best model for demonstrating the capability of [⁶⁸Ga]DOTA-en-pba to recognize tumors. The in vivo PET imaging was done with B16-F10 tumor-bearing SCID mice injected with [⁶⁸Ga]DOTA-en-pba intravenously. Tumor, blood, and urine metabolites were assessed to evaluate the presence of a targeting agent.

Results

The affinity of [⁶⁸Ga]DOTA-en-pba to Sia was demonstrated on B16-F10 melanoma cells, after the production of melanin as well as Sia overexpression was proved to be up to four times higher in this cell line compared to that in Mel-C cells. Biodistribution studies in B16-F10 tumor-bearing SCID mice showed blood clearance at the time points studied, while uptake in the tumor peaked at 60 min post-injection (6.36?±?2.41 % ID/g). The acquired PET images were in accordance with the ex vivo biodistribution results. Metabolite assessment on tumor, blood, and urine samples showed that [⁶⁸Ga]DOTA-en-pba remains unmetabolized up to at least 60 min post-injection.

Conclusions

Our work is the first attempt for in vivo imaging of cancer by targeting overexpression of sialic acid on cancer cells with a radiotracer in PET.

     

Comparison of Ga-68-Labeled Fusarinine C-Based Multivalent RGD Conjugates and [<Superscript>68</Superscript>Ga]NODAGA-RGD—<Emphasis Type="Italic">In Vivo</Emphasis> Imaging Studies in Human Xenograft Tumors

Purpose

Multimeric arginine-glycine-aspartic acid (RGD) peptides have advantages for imaging integrin α_vβ₃ expression. Here, we compared the in vitro and in vivo behavior of three different Ga-68-labeled multimeric Fusarinine C-RGD (FSC-RGD) conjugates, whereby RGD was coupled directly, via a succinic acid or PEG linker (FSC(RGDfE)₃, FSC(succ-RGD)₃, FSC(Mal-RGD)₃). The positron emission tomography/X-ray computed tomography (PET/CT) imaging properties were further compared using [⁶⁸Ga]FSC(succ-RGD)₃ with the monomeric [⁶⁸Ga]NODAGA-RGD in a murine tumor model.

Procedure

FSC-RGD conjugates were labeled with Ga-68, and stability properties were studied. For in vitro characterization, the partition coefficient, integrin α_vβ₃ binding affinity, and cell uptake were determined. To characterize the in vivo properties, biodistribution studies and microPET/CT were carried out using mice bearing either human M21/M21-L melanoma or human U87MG glioblastoma tumor xenografts.

Results

All FSC-RGD conjugates were quantitatively labeled with Ga-68 within 10 min at RT. The [⁶⁸Ga]FSC-RGD conjugates exhibited high stability and hydrophilic character, with only minor differences between the different conjugates. In vitro and in vivo studies showed enhanced integrin α_vβ₃ binding affinity, receptor-selective tumor uptake, and rapid renal excretion resulting in good imaging properties.

Conclusions

The type of linker between FSC and RGD had no pronounced effect on targeting properties of [⁶⁸Ga]FSC-RGD trimers. In particular, [⁶⁸Ga]FSC(succ-RGD)₃ exhibited improved properties compared to [⁶⁸Ga]NODAGA-RGD, making it an alternative for imaging integrin α_vβ₃ expression.

     

Evaluation of Cu-64 and Ga-68 Radiolabeled Glucagon-Like Peptide-1 Receptor Agonists as PET Tracers for Pancreatic β cell Imaging

Purpose

Copper-64 (Cu-64) and Galium-68 (Ga-68) radiolabeled DO3A and NODA conjugates of exendin-4 were used for preclinical imaging of pancreatic β cells via targeting of glucagon-like peptide-1 receptor (GLP-1R).

Procedures

DO3A-VS- and NODA-VS-tagged Cys⁴⁰exendin-4 (DO3A-VS-Cys⁴⁰-exendin-4 and NODA-VS-Cys⁴⁰-exendin-4, respectively) were labeled with Cu-64 and Ga-68 using standard techniques. Biodistribution and dynamic positron emission tomography (PET) were carried out in normal Sprague–Dawley (SD) rats. Ex vivo autoradiography imaging was conducted with freshly frozen pancreatic thin sections.

Results

DO3A-VS- and NODA-VS-Cys⁴⁰-exendin-4 analogues were labeled with Cu-64 and Ga-68 to a specific activity of 518.7?±?3.7 Ci/mmol (19.19?±?0.14 TBq/mmol) and radiochemical yield above 98 %. Biodistribution data demonstrated pancreatic uptake of 0.11?±?0.02 %ID/g for [⁶⁴Cu]DO3A-VS-, 0.14?±?0.02 %ID/g for [⁶⁴Cu]NODA-VS-, 0.11?±?0.03 for [⁶⁸Ga]DO3A-VS-, and 0.26?±?0.03 for [⁶⁸Ga]NODA-VS-Cys⁴⁰-exendin-4. Excess exendin-4 and exendin-(9–39)-amide displaced all four Cu-64 and Ga-68 labeled exendin-4 derivatives in blocking studies.

Conclusions

[⁶⁴Cu]/[⁶⁸Ga]DO3A-VS-Cys⁴⁰- and [⁶⁴Cu]/[⁶⁸Ga]NODA-VS-Cys⁴⁰-exendin-4 can be used as PET imaging agents specific for GLP-1R expressed on β cells. Here, we report the first evidence of pancreatic uptake visualized with exendin-4 derivative in a rat animal model via in vivo dynamic PET imaging.

     

Phage Display Selection, <Emphasis Type="Italic">In Vitro</Emphasis> Characterization,and Correlative PET Imaging of a Novel HER3 Peptide

Purpose

HER3 (ERBB3) is a receptor tyrosine kinase that is implicated in treatment resistance across multiple cancers, including those of the breast, lung, and prostate. Overexpression of HER3 following targeted therapy can occur rapidly and heterogeneously both within a single lesion and across sites of metastasis, making protein quantification by biopsy highly challenging. A global, non-invasive methodology such as positron emission tomography (PET) imaging can permit serial quantification of HER3, providing a useful approach to monitor HER3 expression across the entire tumor burden both prior to and following treatment. PET imaging of HER3 expression may permit a more personalized approach to targeted therapy by allowing for detection of HER3-mediated resistance, in addition to informing clinical trial patient selection for novel therapies targeting HER3.

Procedures

Phage display selection targeting the HER3 extracellular domain was performed in order to develop a peptide with optimal blood clearance and highly accurate HER3 quantification.

Results

The selection converged to a consensus peptide sequence that was subsequently found to bind HER3 with an affinity of 270 ± 151 nM. The peptide, termed HER3P1, was bound with high selectivity to HER3 over other similar receptor tyrosine kinases such as EGFR and HER2. Furthermore, HER3P1 was able to distinguish between high and low HER3-expressing cells in vitro. The peptide was radiolabeled with Ga-68 and demonstrated to specifically bind HER3 by in vivo PET imaging. Uptake of [⁶⁸Ga]HER3P1 was highly specific for HER3-positive tumors, with tumor-to-background ratios ranging from 1.59–3.32, compared to those of HER3-negative tumors, ranging from 0.84–0.93. The uptake of [⁶⁸Ga]HER3P1 also demonstrated high (P < 0.001) correlation with protein expression as quantified by Western blot and confirmed by biodistribution.

Conclusions

HER3P1 accurately quantifies expression of HER3 by PET imaging and has potential utility as a clinical imaging agent.

     

Correlation between the combination of apparent integrated backscatter–spectral centroid shift and bone mineral density

Purpose

To introduce a new diagnostic parameter: the linear combination of apparent integrated backscatter and spectral centroid shift.

Methods

Ultrasonic backscatter measurements were performed at the calcanei of 1262 volunteers in vivo. The hip and spine bone mineral densities of the volunteers were measured using dual X-ray absorptiometry. The apparent integrated backscatter and spectral centroid shift were calculated. A new diagnostic parameter, i.e., the linear combination of apparent integrated backscatter and spectral centroid shift, was introduced and its correlation to bone mineral density was analyzed.

Results

The results show that the combination of apparent integrated backscatter and spectral centroid shift is significantly correlated to bone mineral density (R = 0.73–0.84, n = 1262, p < 0.05), and that this correlation is more significant than the correlation between the apparent integrated backscatter and bone mineral density or the correlation between spectral centroid shift and bone mineral density (R = 0.48–0.69, p < 0.05).

Conclusion

The combination of apparent integrated backscatter and spectral centroid shift can provide the complementary information of attenuation of the two parameters and predict more information about cancellous bone, and may be employed to assess cancellous bone status.

     

A Randomized Trial Investigating the Pharmacokinetics,Pharmacodynamics, and Safety of Subcutaneous Semaglutide Once-Weekly in Healthy Male Japanese and Caucasian Subjects

Introduction

Semaglutide is a glucagon-like peptide-1 analogue for once-weekly subcutaneous treatment of type 2 diabetes. This trial compared the pharmacokinetics, pharmacodynamics, and safety of semaglutide in Japanese and Caucasian subjects.

Methods

In this single-center, double-blind, parallel-group, 13-week trial, 44 healthy male subjects (22 Japanese, 22 Caucasian) were randomized within each race to semaglutide 0.5 mg (n = 8), 1.0 mg (n = 8), placebo 0.5 mg (n = 3) or 1.0 mg (n = 3). The primary endpoint was semaglutide exposure at steady state [area under the curve (AUC_0–168h)].

Results

Steady-state exposure of semaglutide was similar for both populations: AUC_0–168h estimated race ratio (ERR), Japanese/Caucasian: 0.5 mg, 1.06; 1.0 mg, 0.99; maximum concentration (C_max) ERR: 0.5 mg, 1.06; 1.0 mg, 1.02. Exposure after the first dose (0.25 mg) was slightly higher in Japanese versus Caucasian subjects (AUC_0–168h ERR 1.11; C_max ERR 1.14). Dose-dependent increases in AUC_0–168h and C_max occurred in both populations. Accumulation was as expected, based on the half-life (t_1/2, ~ 1 week) and dosing interval of semaglutide. Significant body weight reductions were observed with semaglutide 0.5 mg and 1.0 mg in Japanese (both p ≤ 0.05) and Caucasian (both p ≤ 0.05) subjects versus placebo. No new safety issues were identified.

Conclusions

The pharmacokinetic, pharmacodynamic, and safety profiles of semaglutide were similar in Japanese and Caucasian subjects, suggesting that no dose adjustment is required for the clinical use of semaglutide in Japanese subjects.

Funding

Novo Nordisk A/S, Denmark.

Trial registration

ClinicalTrials.gov identifier NCT02146079. Japanese trial registration number JapicCTI-142550.

     

Reactive Oxygen Species Imaging in a Mouse Model of Inflammatory Bowel Disease

Purpose

Reactive oxygen species (ROS) are important contributors to inflammatory bowel disease (IBD); however, there are insufficient tools for their in vivo evaluation.

Procedures

To determine if a chemiluminescent ROS reporter, coelenterazine, would be a useful tool for the detection of immune cell activation, the macrophage cell line (RAW 264.7) was treated with phorbol myristate acetate (PMA). Additionally, coelenterazine was used to monitor the changes in ROS production over time in a mouse model of IBD.

Results

In vitro, coelenterazine enabled the dynamic monitoring of the RAW 264.7 cell oxidative burst. In vivo, there were early, preclinical, changes in the localization and magnitude of coelenterazine chemiluminescent foci.

Conclusions

Coelenterazine offers a high-throughput method for assessing immune cell activation in culture and provides a means for the in vivo detection and localization of ROS during IBD disease progression.

     

Bioluminescence Imaging to Monitor the Effects of the Hsp90 Inhibitor NVP-AUY922 on NF-κB Pathway in Endometrial Cancer

Purpose

In this study, we first aimed to evaluate the effects in vitro and in vivo, of the Hsp90 inhibitor NVP-AUY922, in endometrial cancer (EC). We also aimed to track nuclear factor kappa B (NF-κB) signalling, a key pathway involved in endometrial carcinogenesis and to check whether NVP-AUY922 treatment modulates it both in vitro and in vivo.

Procedures

I n vitro effects of NVP-AUY922 on EC cell growth and the signalling pathways were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), clonogenic assays, Western Blot and luciferase assay. NVP-AUY922 effect on Ishikawa (IK) xenograft growth was evaluated in vivo, and NF-κB activity was monitored using bioluminescence imaging.

Results

NVP-AUY922 inhibited the growth of three endometrial cell lines tested in vitro. In vivo, NVP-AUY922 reduced tumour growth of 47 % (p?=?0.042) compared to control condition. Moreover, the bioluminescence signal of the tumours harbouring IK NF-κB-LUC cells was significantly reduced in NVP-AUY922-treated animals compared to untreated ones.

Conclusions

NVP-AUY922 reduced EC tumour growth and NF-κB signalling both in vitro and in vivo. As therapeutic resistance of EC remains a challenge for oncologists nowadays, we think that NVP-AUY922 represents a valid alternative to conventional chemotherapy, and we believe that this approach for assessing and tracking the activation of NF-κB pathway may be of therapeutic benefit.

     

Factors and Regional Differences Associated with Endometriosis: A Multi-Country,Case–Control Study

Introduction

The present study aimed to investigate clinical, lifestyle, and environmental factors associated with endometrioma (OMA) and/or deep infiltrating endometriosis (DIE) as determined by case–control comparison [women with superficial peritoneal endometriosis (SUP) or no endometriosis], and compare differences between factor associated with endometriosis at a national level.

Methods

This was three countries (China, Russia, and France), case–control study in 1008 patients. Patients were identified and enrolled during their first routine appointment with their physician post-surgery for a benign gynecologic indication, excluding pregnancy. Retrospective information on symptoms and previous medical history was collected via face-to-face interviews; patients also completed a questionnaire to provide information on current habits. For every DIE patient recruited (n = 143), two women without endometriosis (n = 288), two SUP patients (n = 288), and two OMA patients (n = 288) were recruited.

Results

For the overall population, factors significantly associated (P ≤ 0.05) with DIE or OMA [Odds ratio (OR) >1] were: previous use of hormonal treatment for endometriosis [OR 6.66; 95% confidence interval (CI) 4.05–10.93]; previous surgery for endometriosis (OR 1.95; 95% CI 1.11–3.43); and living or working in a city or by a busy area (OR 1.66; 95% CI 1.09–2.52). Differences between regions with regard to the diagnosis, symptomatology, and treatment of endometriosis exist.

Conclusion

The findings provide insight into potential risk factors for endometriosis and differences between regions in terms of endometriosis management and symptomatology. Further investigations are required to confirm the associations found in this study.

Trial registration

ClinicalTrials.gov identifier, NCT01351051.

Funding

Ipsen.

     

Characterization of Magneto-Endosymbionts as MRI Cell Labeling and Tracking Agents

Purpose

Magneto-endosymbionts (MEs) show promise as living magnetic resonance imaging (MRI) contrast agents for in vivo cell tracking. Here we characterize the biomedical imaging properties of ME contrast agents, in vitro and in vivo.

Procedures

By adapting and engineering magnetotactic bacteria to the intracellular niche, we are creating magneto-endosymbionts (MEs) that offer advantages relative to passive iron-based contrast agents (superparamagnetic iron oxides, SPIOs) for cell tracking. This work presents a biomedical imaging characterization of MEs including: MRI transverse relaxivity (r ₂) for MEs and ME-labeled cells (compared to a commercially available iron oxide nanoparticle); microscopic validation of labeling efficiency and subcellular locations; and in vivo imaging of a MDA-MB-231BR (231BR) human breast cancer cells in a mouse brain.

Results

At 7T, r ₂ relaxivity of bare MEs was higher (250 s^?1 mM^?1) than that of conventional SPIO (178 s^?1 mM^?1). Optimized in vitro loading of MEs into 231BR cells yielded 1–4 pg iron/cell (compared to 5–10 pg iron/cell for conventional SPIO). r ₂ relaxivity dropped by a factor of ~3 upon loading into cells, and was on the same order of magnitude for ME-loaded cells compared to SPIO-loaded cells. In vivo, ME-labeled cells exhibited strong MR contrast, allowing as few as 100 cells to be detected in mice using an optimized 3D SPGR gradient-echo sequence.

Conclusions

Our results demonstrate the potential of magneto-endosymbionts as living MR contrast agents. They have r ₂ relaxivity values comparable to traditional iron oxide nanoparticle contrast agents, and provide strong MR contrast when loaded into cells and implanted in tissue.

     

Bioluminescence Imaging of Colonization and Clearance Dynamics of <Emphasis Type="Italic">Brucella Suis</Emphasis> Vaccine Strain S2 in Mice and Guinea Pigs

Purpose

The goal of this study was to develop a plasmid-based lux bio-reporter for use to obtain in vivo images of Brucella suis vaccine strain 2 (B.suis S2) infection with high resolution and good definition.

Procedures

The pBBR-lux (pBBR1MCS-2-lxCDABE) plasmid that carries the luxCDABE operon was introduced into B. suis S2 by electroporation yielding B. suis S2-lux. The spatial and temporal transit of B. suis S2 in mice and guinea pigs was monitored by bioluminescence imaging.

Results

The plasmid pBBR-lux is stable in vivo and does not appear to impact the virulence or growth of bacteria. This sensitive luciferase reporter could represent B. suis S2 survival in real time. B. suis S2 mainly colonized the lungs, liver, spleen, and uterus in mice and guinea pigs as demonstrated by bioluminescence imaging.

Conclusion

The plasmid-based lux bioreporter strategy can be used to obtain high resolution in vivo images of B. suis S2 infection in mice and guinea pigs.

     

Optimization of a Labeling and Kit Preparation Method for Ga-68 Labeled DOTATATE,Using Cation Exchange Resin Purified Ga-68 Eluates Obtained from a Tin Dioxide <Superscript>68</Superscript>Ge/<Superscript>68</Superscript>Ga Generator

Purpose

The aim of this study was to optimize a radiolabeling method using cationic processed Ga-68 eluates from a SnO₂-based ⁶⁸Ge/⁶⁸Ga generator, followed by the development of DOTA-Tyr³-Thre⁸-octreotide (DOTATATE) kits.

Procedures

Diluted generator eluates were adsorbed on a SCX resin and desorbed with acidified 5 M NaCl solution. Optimized labeling conditions were determined by variation of pH, using 35 μg DOTATATE and sodium acetate buffer. DOTATATE kits were developed based on optimized radiolabeling conditions, were labeled, and evaluated.

Results

Optimized labeling conditions resulted in a radiolabeling efficiency of around 99 % and radiochemical yield of almost 85 %. Different kit preparation methods did not significantly influence the radiolabeling results. Kits were found to be stable over 3 months.

Conclusion

A labeling method using SCX-processed Ga-68 eluates was optimized. DOTATATE kits specifically for these SCX-processed Ga-68 eluates were successfully formulated. A post-labeling Sep-Pak C18 purification should be optional.

     

Reproducibility of Contrast-Enhanced Ultrasound in Mice with Controlled Injection

Purpose

Sensitivity of contrast-enhanced ultrasound (CEUS) to microvascular flow modifications can be limited by intra-injection variability (injected dose, rate, volume).

Procedures

To evaluate the effect of injection variability on microvascular flow evaluation, CEUS was compared between controlled and manual injections where enhancement was assessed in vitro within a flow phantom, in normal murine kidney (N?=?12) and in murine ectopic tumors (N?=?10).

Results

For both in vitro and in vivo measurements in the renal cortex, controlled injections significantly improved reproducibility of functional parameter estimation. Their coefficient of variation (CV) in the renal cortex ranged from 4 to 19 % for controlled injection vs. 5 to 43 % for manual injections. For measurements in tumors, controlled injection only decreased the CV significantly for the mean transit time. In tumors, multiple injections of contrast agent with a 15-min delay between each were shown to strongly modify contrast uptake by facilitating penetration of microbubbles.

Conclusion

Improved reproducibility of CEUS assessments in murine models should provide more robust quantification of flow parameters and more sensitive evaluation of tumor modifications in therapeutic models.

     

Effect of synbiotic therapy on the incidence of ventilator associated pneumonia in critically ill patients: a randomised,double-blind,placebo-controlled trial

Objective

To investigate the effect of enteral Synbiotic 2000 FORTE^® (a mixture of lactic acid bacteria and fibre) on the incidence of ventilator associated pneumonia (VAP) in critically ill patients.

Design

Prospective, randomised, double blind, placebo controlled trial.

Setting

Tertiary referral centre, general Adult Intensive Care Unit (ICU).

Patients and participants

259 enterally fed patients requiring mechanical ventilation for 48 h or more were enrolled.

Intervention

All patients were enterally fed as per a standard protocol and randomly assigned to receive either synbiotic 2000 FORTE^® (twice a day) or a cellulose-based placebo for a maximum of 28 days.

Measurements and results

Treatment group (n = 130) was well matched with placebo group (n = 129) for age (mean 49.5 and 50 years, respectively) and APACHE II score (median 17 for both). Oropharyngeal microbial flora and colonisation rates were unaffected by synbiotics. The overall incidence of VAP was lower than anticipated (11.2%) and no statistical difference was demonstrated between groups receiving synbiotic and placebo in the incidence of VAP (9 and 13%, P = 0.42), VAP rate per 1,000 ventilator days (13 and 14.6, P = 0.91) or hospital mortality (27 and 33%, P = 0.39), respectively.

Conclusions

Enteral administration of Synbiotic 2000 FORTE^® has no statistically significant impact on the incidence of VAP in critically ill patients.

     

A Single-Dose,Crossover-Design Bioequivalence Study Comparing Two Nicotine Gum Formulations in Healthy Subjects

Introduction

Nicotine replacement therapy (NRT) benefits smokers who wish to quit; nicotine gum represents one NRT. New formulations of nicotine gum have been developed to consider consumer preferences and needs. A new mint-flavored nicotine gum with a different texture was developed that may provide a more appealing taste and chewing experience. This study evaluated this new nicotine gum (2 and 4 mg strengths) for bioequivalence versus the original flavor sugar-free nicotine gum at corresponding dosages.

Methods

All subjects randomized in this crossover study received a single dose of all treatments, i.e., 2 and 4 mg doses of test and reference gums, separated by 2–7 days of washout between treatments. Subjects’ maximal plasma nicotine concentration (C_max) and extent of nicotine absorption (AUC_0–t) following the administration of each treatment were calculated from plasma nicotine concentrations. Ratios of test/reference for C_max and AUC_0–t were calculated to evaluate bioequivalence between the two products.

Results

Both 2 and 4 mg doses of the new mint-flavored nicotine gum were bioequivalent to the dose-matched reference product as determined by the ratio of the geometric means and their 90% confidence intervals for C_max and AUC_0–t as well as secondary pharmacokinetic parameters. The safety profiles of the test and reference gums were similar; all treatments were well tolerated.

Conclusions

A new mint-flavored nicotine gum with modified taste and texture is bioequivalent to the original flavor sugar-free nicotine gum at both the 2 and 4 mg dosage strengths and has a similar safety profile.

Funding

GlaxoSmithKline.

Trial Registration

ClinicalTrials.gov identifier NCT01847443.

     

Efficacy of the echo pattern classification of ovarian tumors 2000 in conjunction with transvaginal ultrasonography for diagnosis of ovarian masses

Purpose

Because of the need for rapid, accurate clinical differentiation between malignant and benign ovarian masses, we investigated the diagnostic efficacy of the echo pattern classification used together with transvaginal ultrasound.

Methods

We classified, on the basis of six echo pattern types, transvaginal ultrasound images of 405 ovarian masses treated surgically between January 2011 and December 2012. We compared the resulting classifications to the postoperative histopathologic diagnoses and computed the diagnostic sensitivity and specificity of the echo pattern-based classification for malignancy.

Results

Our review yielded the following echo patterns: type I, n = 61; type II; n = 154; type III, n = 82; type IV, n = 61; type V, n = 34; and type VI, n = 13. Histopathologically, there were 75 borderline malignant/malignant tumors and 330 benign tumors. Diagnostic sensitivity was 80.0 % and specificity was 85.5 % when echo types I–III were categorized as benign and types IV–VI were categorized as malignant. Further, with respect to benign tumors: sensitivity and specificity for chocolate cysts were 85.5 and 88.4 %, respectively, and for dermoid cysts were 67.2 and 97.9 %, respectively.

Conclusions

With the echo pattern classification, ovarian masses can be diagnosed easily and accurately upon transvaginal ultrasound.

     

Assessing Glomerular Filtration in Small Animals Using [<Superscript>68</Superscript>Ga]DTPA and [<Superscript>68</Superscript>Ga]EDTA with PET Imaging

Purpose

Determining the glomerular filtration rate (GFR) is essential for clinical medicine but also for pre-clinical animal studies. Functional imaging using positron emission tomography (PET) allows repetitive almost non-invasive measurements. The aim of the study was the development and evaluation of easily synthesizable PET tracers for GFR measurements in small animals.

Procedures

Diethylenetriaminepentaacetic acid (DTPA) and ethylenediaminetetraacetic acid (EDTA) were labeled with Ga-68. The binding to blood cells and plasma proteins was tested in vitro. The distribution of the tracers in rats was analyzed by PET imaging and ex vivo measurements. From the time-activity-curve of the blood compartment (heart) and the total tracer mass excreted by the kidney, the GFR was calculated. These values were compared directly with the inulin clearance in the same animals.

Results

Both tracers did not bind to blood cells. [⁶⁸Ga]DPTA but not [⁶⁸Ga]EDTA showed strong binding to plasma proteins. For this reason, [⁶⁸Ga]DPTA stayed much longer in the blood and only 30 % of the injected dose was eliminated by the kidney within 60 min whereas the excretion of [⁶⁸Ga]EDTA was 89 ± 1 %. The calculated GFR using [⁶⁸Ga]EDTA was comparable to the measured inulin clearance in the same animal. Using [⁶⁸Ga]-DPTA, the measurements led to values which were 80 % below the normal GFR. The results also revealed that definition of the volume of interest for the blood compartment affects the calculation and may lead to a slight overestimation of the GFR.

Conclusions

[⁶⁸Ga]EDTA is a suitable tracer for GFR calculation from PET imaging in small animals. It is easy to be labeled, and the results are in good accordance with the inulin clearance. [⁶⁸Ga]DTPA led to a marked underestimation of GFR due to its strong binding to plasma proteins and is therefore not an appropriate tracer for GFR measurements.

     

Multimodal Genetic Approach for Molecular Imaging of Vasculature in a Mouse Model of Melanoma

Purpose

In this study, we evaluated a genetic approach for in vivo multimodal molecular imaging of vasculature in a mouse model of melanoma.

Procedures

We used a novel transgenic mouse, Ts-Biotag, that genetically biotinylates vascular endothelial cells. After inoculating these mice with B16 melanoma cells, we selectively targeted endothelial cells with (strept)avidinated contrast agents to achieve multimodal contrast enhancement of Tie2-expressing blood vessels during tumor progression.

Results

This genetic targeting system provided selective labeling of tumor vasculature and showed in vivo binding of avidinated probes with high specificity and sensitivity using microscopy, near infrared, ultrasound, and magnetic resonance imaging. We further demonstrated the feasibility of conducting longitudinal three-dimensional (3D) targeted imaging studies to dynamically assess changes in vascular Tie2 from early to advanced tumor stages.

Conclusions

Our results validated the Ts-Biotag mouse as a multimodal targeted imaging system with the potential to provide spatio-temporal information about dynamic changes in vasculature during tumor progression.