Radiosynthesis of Stable 198Au-Nanoparticles by Neutron Activation of αvβ3-Specific AuNPs for Therapy of Tumor Angiogenesis

This paper reports on the development of stable tumor-specific gold nanoparticles (AuNPs) activated by neutron irradiation as a therapeutic option for the treatment of cancer with high tumor angiogenesis. The AuNPs were designed with different mono- or dithiol-ligands and decorated with different amounts of Arg-Gly-Asp (RGD) peptides as a tumor-targeting vector for αvβ3 integrin, which is overexpressed in tissues with high tumor angiogenesis. The AuNPs were evaluated for avidity in vitro and showed favorable properties with respect to tumor cell accumulation. Furthermore, the therapeutic properties of the [198Au]AuNPs were evaluated in vitro on U87MG cells in terms of cell survival, suggesting that these [198Au]AuNPs are a useful basis for future therapeutic concepts.

Metallacages with 2,6-dipicolinoylbis(N,N-dialkylthioureas) as novel platforms in nuclear medicine for 68Ga, 177Lu and 198Au

BACKGROUND

Heterometallic gold metallacages are of great interest for the incorporation of several cations. Especially in nuclear medicine, those metallacages can serve as a platform for radionuclides relevant for imaging or therapy (e.g. 68Ga or 177Lu). Moreover, the radionuclide 198Au is an attractive beta emitter, for potential application in nuclear medicine. Here, we aim to synthesize a new set of gold metallacages and to study their ability to coordinate to 68Ga, 177Lu and 198Au.

RESULTS

New heterometallic gold metallacages of composition [M{Au(Lmorph-κS)}3] (M = La3+, Tb3+, Lu3+ or Y3+) and [Ga{Au(Lmorph-κS)}2]NO3 have been synthesized from 2,6-dipicolinoylbis(N,N-morpholinylthiourea) (H2Lmorph) with [AuCl(THT)] and the target M3+ metal ions in yields ranging from 33 (Lu) to 62% (Tb). The characterization of the compounds bases on ESI-MS, 1H NMR, IR, EA and single-crystal X-ray diffraction techniques (all except the Ga derivative). Selected gold cages derived from H2Lmorph were compared to previously reported gold cages that were derived from 2,6-dipicolinoylbis(N,N-diethylthiourea) (H2Ldiethyl). The tested metallacages show similar IC50 values close to that of auranofin in four different cancer cell lines (MCF-7, PC-3, U383, U343), e.g. 4.5 ± 0.7 µM for [Ga{Au(Ldiethyl)}2]NO3 on PC-3. The radiolabeling experiments thereof show high radiochemical purities with 68Ga and 198Au and low radiochemical purity with 177Lu.

CONCLUSIONS

The results indicate that these gold metallacages could serve as a novel platform for inclusion of different (radio)nuclides with potential theranostic applications in nuclear medicine.

Reactor activations to constrain astrophysically relevant cross sections

The determination of astrophysically relevant neutron-induced cross sections is particularly difficult when the involved isotopes are radioactive or the cross sections are very small. Activation experiments at reactors offer the possibility to overcome these limitations with high neutron fluxes. The flux determination is typically based on the activation of two monitors with known cross sections to separate the different flux components. The usually applied cadmium difference method allows a distinction between the thermal and the epithermal part. By a combination of two linear functions representing both monitors the neutron flux components can be determined. However, if more than two monitors are used, the linear system of equations is overdetermined, which allows the identification of a probability distribution. In this proceeding, the feasibility and relevance of this method is demonstrated.

A new Collinear Apparatus for Laser Spectroscopy and Applied Science (COALA)

We present a new collinear laser spectroscopy setup that has been designed to overcome systematic uncertainty limits arising from high-voltage and frequency measurements, beam superposition, and collisions with residual gas that are present in other installations utilizing this technique. The applied methods and experimental realizations are described, including an active stabilization of the ion-source potential, new types of ion sources that have not been used for collinear laser spectroscopy so far, dedicated installations for pump-and-probe measurements, and a versatile laser system referenced to a frequency comb. The advanced setup enables us to routinely determine transition frequencies, which was so far demonstrated only for a few cases and with lower accuracy at other facilities. It has also been designed to perform accurate high-voltage measurements for metrological applications. Demonstration and performance measurements were carried out with Ca⁺ and In⁺ ions.

The research reactor TRIGA Mainz – a strong and versatile neutron source for science and education

The TRIGA Mark II-reactor at the Johannes Gutenberg University Mainz (JGU) is one of three research reactors in Germany. The TRIGA Mainz became first critical on August 3rd, 1965. It can be operated in the steady state mode with a maximum power of 100 kWth and in the pulse mode with a peak power of 250 MWth and a pulse length of 30 ms. The TRIGA Mainz is equipped with a central thimble, a rotary specimen rack, three pneumatic transfer systems, four beam tubes, and a graphite thermal column. The TRIGA Mainz is intensively used both for basic and applied research in nuclear chemistry and nuclear physics. Two sources for ultra-cold neutrons (UCN) are operational at two beam ports. At a third beam port a Penning-Trap for highly precise mass measurements of exotic nuclides is installed. Education and training is another main field of activity. Here, various courses in nuclear and radiochemistry, reactor operation and reactor physics are held for scientists, advanced students, engineers, and technicians utilizing the TRIGA Mainz reactor.

New Nuclear Magnetic Moment of ^{209}Bi: Resolving the Bismuth Hyperfine Puzzle

A recent measurement of the hyperfine splitting in the ground state of Li-like ^{208}Bi^{80+} has established a "hyperfine puzzle"-the experimental result exhibits a 7σ deviation from the theoretical prediction [J. Ullmann et al., Nat. Commun. 8, 15484 (2017)NCAOBW2041-172310.1038/ncomms15484; J. P. Karr, Nat. Phys. 13, 533 (2017)NPAHAX1745-247310.1038/nphys4159]. We provide evidence that the discrepancy is caused by an inaccurate value of the tabulated nuclear magnetic moment (μ_{I}) of ^{209}Bi. We perform relativistic density functional theory and relativistic coupled cluster calculations of the shielding constant that should be used to extract the value of μ_{I}(^{209}Bi) and combine it with nuclear magnetic resonance measurements of Bi(NO_{3})_{3} in nitric acid solutions and of the hexafluoridobismuthate(V) BiF_{6}^{-} ion in acetonitrile. The result clearly reveals that μ_{I}(^{209}Bi) is much smaller than the tabulated value used previously. Applying the new magnetic moment shifts the theoretical prediction into agreement with experiment and resolves the hyperfine puzzle.

Precision Test of Many-Body QED in the Be+ 2p Fine Structure Doublet Using Short-Lived Isotopes

Absolute transition frequencies of the 2s 2S{1/2}→2p2P{1/2,3/2} transitions in Be^{+} were measured for the isotopes ^{7,9-12}Be. The fine structure splitting of the 2p state and its isotope dependence are extracted and compared to results of ab initio calculations using explicitly correlated basis functions, including relativistic and quantum electrodynamics effects at the order of mα(6) and mα(7) ⁢ln α. Accuracy has been improved in both the theory and experiment by 2 orders of magnitude, and good agreement is observed. This represents one of the most accurate tests of quantum electrodynamics for many-electron systems, being insensitive to nuclear uncertainties.

Test of time dilation using stored Li+ ions as clocks at relativistic speed

We present the concluding result from an Ives-Stilwell-type time dilation experiment using 7Li+ ions confined at a velocity of β=v/c=0.338 in the storage ring ESR at Darmstadt. A Λ-type three-level system within the hyperfine structure of the 7Li+3S1 →3P2 line is driven by two laser beams aligned parallel and antiparallel relative to the ion beam. The lasers' Doppler shifted frequencies required for resonance are measured with an accuracy of <4×10(-9) using optical-optical double resonance spectroscopy. This allows us to verify the special relativity relation between the time dilation factor γ and the velocity β, γ√1-β2=1 to within ±2.3×10(-9) at this velocity. The result, which is singled out by a high boost velocity β, is also interpreted within Lorentz invariance violating test theories.

Diffusion-weighted MR imaging of benign and malignant breast lesions before and after contrast enhancement

PURPOSE

Many publications describe the use of diffusion-weighted imaging (DWI) in breast MRI. This article addresses the question of when to apply the DWI sequence in the course of the scan protocol. The effect of T1-shortening contrast media (CM) on the ADC values of breast lesions is investigated.

MATERIALS AND METHODS

Data were acquired on a 1.5 T scanner. 60 patients with 79 lesions (20 benign, 59 malignant) were included. The DWI sequence (4 mm slice thickness, b-values: 50, 400, 800) was applied before and after CM administration. Before calculating the ADC map, the b50, b400 and b800 series were analyzed concerning lesion displacement. ADC values before and after CM application were compared.

RESULTS

The mean lesion size was 1.5 ± 0.8 cm. On the basis of the b50 and b400 measurements, the mean ADC value of benign lesions was 1.89 ± 0.30 × 10-3 mm2/s before and 1.85 ± 0.28 ×10-3 mm2/s after CM administration. The consecutive values for two pure mucinous carcinomas were 1.88 × 10-3 mm2/s and 1.81 × 103 mm2/s and for the remaining malignant lesions 1.00 ± 0.18 × 10-3 mm2/s and 0.88 ± 0.21 × 10-3 mm2. On the basis of the b50, b400 and b800 measurements, the mean ADC value of benign lesions was 1.99 ± 0.37 × 10-3 mm2/s before and 1.97 ± 0.30 × 10-3 mm2/s after CM application, whereas the mean ADC value of the malignant lesions was 0.90 ± 0.14 × 10-3 mm2/s before and 0.80 ± 0.14 × 10-3 mm2/s after CM application. While there was no significant change for benign lesions, the ADC value decrease in post-contrast malignant lesions was highly significant.

CONCLUSION

DWI after CM is possible and even leads to slightly better lesion discrimination between benign and malignant. However, further studies need to be performed to verify this. Citation Format: • Janka R, Hammon M, Geppert C et al. Diffusion-Weighted MR Imaging of Benign and Malignant Breast Lesions Before and After Contrast Enhancement. Fortschr Röntgenstr 2014; 186: 130 - 135.

Nuclear spins and moments of Ga isotopes reveal sudden structural changes between N=40 and N=50

Collinear laser spectroscopy was performed on Ga (Z=31) isotopes at ISOLDE, CERN. A gas-filled linear Paul trap (ISCOOL) was used to extend measurements towards very neutron-rich isotopes (N=36-50). A ground state (g.s.) spin I=1/2 is measured for 73Ga, being near degenerate with a 3/2{-} isomer (75  eV≲E{ex}≲1  keV). The 79Ga g.s., with I=3/2, is dominated by protons in the πf{5/2} orbital and in 81Ga the 5/2{-} level becomes the g.s. The data are compared to shell-model calculations in the f{5/2}pg{9/2} model space, calling for further theoretical developments and new experiments.

Labeling the human skeleton with 41Ca to assess changes in bone calcium metabolism

Bone research is limited by the methods available for detecting changes in bone metabolism. While dual X-ray absorptiometry is rather insensitive, biochemical markers are subject to significant intra-individual variation. In the study presented here, we evaluated the isotopic labeling of bone using 41Ca, a long-lived radiotracer, as an alternative approach. After successful labeling of the skeleton, changes in the systematics of urinary 41Ca excretion are expected to directly reflect changes in bone Ca metabolism. A minute amount of 41Ca (100 nCi) was administered orally to 22 postmenopausal women. Kinetics of tracer excretion were assessed by monitoring changes in urinary 41Ca/40Ca isotope ratios up to 700 days post-dosing using accelerator mass spectrometry and resonance ionization mass spectrometry. Isotopic labeling of the skeleton was evaluated by two different approaches: (i) urinary 41Ca data were fitted to an established function consisting of an exponential term and a power law term for each individual; (ii) 41Ca data were analyzed by population pharmacokinetic (NONMEM) analysis to identify a compartmental model that describes urinary 41Ca tracer kinetics. A linear three-compartment model with a central compartment and two sequential peripheral compartments was found to best fit the 41Ca data. Fits based on the use of the combined exponential/power law function describing urinary tracer excretion showed substantially higher deviations between predicted and measured values than fits based on the compartmental modeling approach. By establishing the urinary 41Ca excretion pattern using data points up to day 500 and extrapolating these curves up to day 700, it was found that the calculated 41Ca/40Ca isotope ratios in urine were significantly lower than the observed 41Ca/40Ca isotope ratios for both techniques. Compartmental analysis can overcome this limitation. By identifying relative changes in transfer rates between compartments in response to an intervention, inaccuracies in the underlying model cancel out. Changes in tracer distribution between compartments were modeled based on identified kinetic parameters. While changes in bone formation and resorption can, in principle, be assessed by monitoring urinary 41Ca excretion over the first few weeks post-dosing, assessment of an intervention effect is more reliable approximately 150 days post-dosing when excreted tracer originates mainly from bone.

Precision branching ratio measurement for the superallowed beta+ emitter 62Ga and isospin-symmetry-breaking corrections in A>or=62 nuclei

A high-precision branching ratio measurement for the superallowed beta+ decay of 62Ga was performed at the Isotope Separator and Accelerator radioactive ion beam facility. Nineteen gamma rays emitted following beta+ decay of 62Ga were identified, establishing the dominant superallowed branching ratio to be (99.861+/-0.011)%. Combined with recent half-life and Q-value measurements, this branching ratio yields a superallowed ft value of 3075.6+/-1.4 s for 62Ga decay. These results demonstrate the feasibility of high-precision superallowed branching ratio measurements in the A>or=62 mass region and provide the first stringent tests of the large isospin-symmetry-breaking effects predicted for these decays.

Five-year results of laparoscopic Toupet fundoplication as the primary surgical repair in GERD patients: is it durable?

INTRODUCTION

Most surgeons operate on gastroesophageal reflux disease (GERD) patients using the concept of "tailored approach," which depends on esophageal motility. We have abandoned this concept and performed laparoscopic Toupet fundoplication in all patients suffering from GERD, independent of their esophageal motility.

METHODS

In a prospective trial we have assessed and evaluated our 5-year results of the first 100 consecutive patients treated with laparoscopic Toupet fundoplication. All patients were evaluated preoperatively by endoscopy and 24-h pH manometry. The patients were followed up clinically 1, 2, 6, 12 and 60 months postoperatively. The course of clinical DeMeester score, appearance and treatment of wrap-related side-effects as well as long-term outcome and patient satisfaction were evaluated.

RESULTS

The 5-year follow-up rate was 87%. Laparoscopic Toupet fundoplication achieved a 5-year healing rate of GERD in 85%. Of all operated patients, 3.5% had to be reinstalled on a regular PPI treatment because of postoperative GERD reappearance. The median clinical DeMeester score decreased from 4.27 +/- 1.5 points preoperatively to 0.47 +/- 0.9 points 5 years postoperatively (p < 0.0005). Because of persistent postoperative dysphagia, 5% of the patients required endoscopic dilatation therapy. Persistent postoperative gas-bloat syndrome occurred in 1.1%. Wrap dislocation was identified in 3.4% of patients. Reoperation rate was 5%. Total morbidity rate was 19.5% and operative related mortality rate was 0%. Overall, 96.6% of patients were pleased with their outcome at late follow-up, and 95.4% of patients stated they would consider undergoing laparoscopic fundoplication again if necessary.

CONCLUSION

Our long-term results showing a low recurrence and morbidity rate of laparoscopic Toupet fundoplication encourage us to continue to perform this procedure as the primary surgical repair in all GERD patients, independent of their esophageal motility. Laparoscopic Toupet fundoplication has proven to be a safe and successful therapeutic option in GERD patients.

Novel photoreception system in sponges? Unique transmission properties of the stalk spicules from the hexactinellid Hyalonemasieboldi

Sponges (phylum Porifera) of the classes Hexactinellida and Demospongiae possess a skeleton composed of siliceous spicules, which are synthesized enzymatically. The longest spicules are found among the Hexactinellida, with the stalk spicules (length: 30 cm; diameter: 300 microm) of Hyalonema sieboldi as prominent examples. These spicules are constructed around a central axial filament, which is formed by approximately 40 siliceous layers. The stratified spicules function as optical glass fibers with unique properties. If free-spaced coupled with a white light source (WLS), the entire fiber is illuminated. Special features of the light transmission: (i) only wavelengths between 615 and 1310 nm can pass through the fibers and (ii) light below wavelengths of 615 nm and above 1310 nm is completely cut-off. The transmission efficiency is around 60% (measured at 1080-1100 nm [length of the fiber: 5 cm]). The spicules acts as sharp high- and low-pass filters, suggesting that these silica-based fibers might be involved in a photoreception system. This assumption is supported by the finding that sponges are provided with a bioluminescent system. It is hypothesized that the spicules/siliceous fibers might be involved in a photoreception system in these animals.

Trace determination of gadolinium in biomedical samples by diode laser-based multi-step resonance ionization mass spectrometry

The application of high-resolution multi-step resonance ionization mass spectrometry (RIMS) to the trace determination of the rare earth element gadolinium is described. Utilizing three-step resonant excitation into an autoionizing level, both isobaric and isotopic selectivity of >10(7) were attained. An overall detection efficiency of approximately 10(-7) and an isotope specific detection limit of 1.5 x 10(9) atoms have been demonstrated. When targeting the major isotope (158)Gd, this corresponds to a total Gd detection limit of 1.6 pg. Additionally, linear response has been demonstrated over a dynamic range of six orders of magnitude. The method has been used to determine the Gd content in various normal and tumor tissue samples, taken from a laboratory mouse shortly after injection of gadolinium diethylenetriaminepentaacetic acid dimeglumine (Gd-DTPA), which is used as a contrast agent for magnetic resonance imaging (MRI). The RIMS results show Gd concentrations that vary by more than two orders of magnitude (0.07-11.5 microg mL(-1)) depending on the tissue type. This variability is similar to that observed in MRI scans that depict Gd-DTPA content in the mouse prior to dissection, and illustrates the potential for quantitative trace analysis in microsamples of biomedical materials.

An invitation for medical educators to focus on ethical and policy issues in research and scholarly practice

Medical education research and medical education practice both involve being methodical, innovative, self-observing, forward-looking, and open to peer review, and both are scholarly activities. For these reasons, distinguishing between these two activities is often difficult. There are three important reasons to clarify the distinctions: the moral difference between education research and education practice; federal regulations governing education research that require more safeguards than often exist in education practice; and the fact that student participants in research have characteristics in common with members of special populations. The authors explain why attention to issues of safeguards in education research and practice is likely to grow at academic health centers, yet maintain that these issues are neglected in the medical education literature. They demonstrate this with findings from their review of 424 education research reports published in 1988 and 1989 and in 1998 and 1999 in two major medical education journals. Each article was evaluated for documentation of six ethically important safeguards and features (e.g., informed consent). The rates of reporting the six features and safeguards were relatively low (3-27%). Nearly half (47%) of the empirical reports offered no indication of ethically important safeguards or features, and no article mentioned all six. Furthermore, those rates did not increase substantially after ten years. The authors discuss a number of implications of their findings for faculty, training institutions, students, and editors and peer reviewers, and conclude with the hope that their findings will raise awareness of these neglected issues in medical education and will stimulate all those involved to reflect upon the issues and set standards on the ethical aspects of research and scholarly practice.

Uncertainty and opposition of medical students toward assisted death practices

To explore medical students' views of assisted death practices in patient cases that describe different degrees and types of physical and mental suffering, an anonymous survey was administered to all students at one medical school. Respondents were asked about the acceptability of assisted death activities in five patient vignettes and withdrawal of life support in a sixth vignette. In the vignettes, actions were performed by four possible agents: the medical student personally; a referral physician; physicians in general; or non-physicians. Of 306 medical students, 166 (54%) participated. Respondents expressed opposition or uncertainty about assisted death practices in the five patient cases that illustrated severe forms of suffering which were secondary to amyotrophic lateral sclerosis, treatment-resistant depressive and somatoform disorders, antisocial and sexually violent behavior, or AIDS. Students supported the withdrawal of life support in the sixth vignette depicting exceptional futility secondary to AIDS. Students were especially opposed to their own involvement and to the participation of non-physicians in assisted death activities. Differences in views related to sex, religious beliefs, and personal philosophy were found. Medical students do not embrace assisted death practices, although they exhibit tolerance regarding the choices of medical colleagues. How these attributes of medical students will translate into future behaviors toward patients and peers remains uncertain. Medical educators must strive to understand the perspectives of physicians-in-training. Expanded, empirically informed education that is attuned to the attitudes of medical students may be helpful in fulfilling the responsibility of imparting optimal clinical care skills.

41Ca ultratrace determination with isotopic selectivity > 10(12) by diode-laser-based RIMS

41Ca ultratrace determination by diode-laser-based resonance ionization mass spectrometry with extremely high isotopic selectivity is presented. Application to environmental dosimetry of nuclear reactor components, to cosmochemical investigations of production cross sections, and biomedical isotope-tracer studies of human calcium kinetics are discussed. Future investigations are possible use in 41Ca-radiodating. Depending on the application, 41Ca isotopic abundances in the range of 10(-9) to 10(-15) relative to the dominant stable isotope 40Ca must be determined. Either double- or triple-resonance optical excitation with narrow-band extended cavity diode lasers and subsequent non-resonant photoionization of calcium in a collimated atomic beam were used. The resulting photoions are detected with a quadrupole mass spectrometer optimized for background reduction and neighboring mass suppression. Applying the full triple-resonance scheme provides a selectivity of approximately 5 x 10(12) in the suppression of neighboring isotopes and > 10(8) for isobars, together with an overall detection efficiency of approximately 5 x 10(-5). Measurements on a variety of sample types are discussed; the accuracy and reproducibility of the resulting 41Ca/40Ca isotope ratios was better than 5%.

Placebos and paradoxes in psychiatric research: an ethics perspective

The use of placebos in clinical trials, particularly in research with mentally ill people, has emerged as a subject of considerable controversy. We first outline ethical aspects of the primary scientific arguments for and against placebo use in research. Three examples of paradoxical aspects of the ethical use of placebos are discussed: involvement of relatively more vulnerable populations, use of apparently "less than standard" therapy, and the omission of information in placebo comparisons. In the current scientific and regulatory context, placebo use in psychiatric research may be necessary for scientific reasons, and when certain conditions are present, it may be justified on ethical grounds. Four key recommendations to facilitate the ethical use of placebos in research trials are presented. We conclude that placebo trials should be undertaken only after careful evaluation of alternative scientific strategies and, as with all human research, with great respect and genuine consideration for the individuals who choose to participate in these protocols.