Imaging of Magnetic Nanoparticles With Permeability Tomography.

Magnetic nanoparticles are being increasingly used in numerous biomedical applications for diagnosis and therapy. During the course of these applications nanoparticle biodegradation and body clearance may occur. In this context, a portable, non-invasive, non-destructive and contactless imaging device can be relevant to trace the nanoparticle distribution before and after the medical procedure. We present a method for in vivo imaging the nanoparticles based on the magnetic induction technique, and we show how to properly tune it for magnetic permeability tomography, maximizing the permeability selectivity. A tomograph prototype was designed and built to demonstrate the feasibility of the proposed method. It includes data collection, signal processing and image reconstruction. Useful selectivity and resolution are achieved on phantoms and animals, proving that the device can be used to monitor the presence of magnetic nanoparticles without requiring any particular sample preparation. By this way, we show that magnetic permeability tomography may become a powerful technique to assist medical procedures.

Small-angle X-ray scattering to quantify the incorporation and analyze the disposition of magnetic nanoparticles inside cells.

Access to detailed information on cells loaded with nanoparticles with nanoscale precision is of a long-standing interest in many areas of nanomedicine. In this context, designing a single experiment able to provide statistical mean data from a large number of living unsectioned cells concerning information on the nanoparticle size and aggregation inside cell endosomes and accurate nanoparticle cell up-take is of paramount importance. Small-angle X-ray scattering (SAXS) is presented here as a tool to achieve such relevant data. Experiments were carried out in cultures of B16F0 murine melanoma and A549 human lung adenocarcinoma cell lines loaded with various iron oxide nanostructures displaying distinctive structural characteristics. Five systems of water-dispersible magnetic nanoparticles (MNP) of different size, polydispersity and morphology were analyzed, namely, nearly monodisperse MNP with 11 and 13 nm mean size coated with meso-2,3-dimercaptosuccinic acid, more polydisperse 6 nm colloids coated with citric acid and two nanoflowers (NF) systems of 24 and 27 nm in size resulting from the aggregation of 8 nm MNP. Up-take was determined for each system using B16F0 cells. Here we show that SAXS pattern provides high resolution information on nanoparticles disposition inside endosomes of the cytoplasm through the structure factor analysis, on nanoparticles size and dispersity after their incorporation by the cell and on up-take quantification from the extrapolation of the intensity in absolute scale to null scattering vector. We also report on the cell culture preparation to reach sensitivity for the observation of MNP inside cell endosomes using high brightness SAXS synchrotron source. Our results show that SAXS can become a valuable tool for analyzing MNP in cells and tissues.

Co-expression of transcription factor AP-2beta (TFAP2B) and GATA3 in human mammary epithelial cells with intense, apicobasal immunoreactivity for CK8/18.

AP-2ß is a new mammary epithelial differentiation marker and its expression is preferentially retained and enhanced in lobular carcinoma in situ and invasive lobular breast cancer. In normal breast epithelium AP-2ß is expressed in a scattered subpopulation of luminal cells. So far, these cells have not been further characterized. Co-expression of AP-2ß protein and luminal epithelium markers (GATA3, CK8/18), hormone receptors [estrogen receptor (ER), androgen receptor (AR)] and candidate stem cells markers (CK5/14, CD44) were assessed by double-immunofluorescence staining in normal mammary gland epithelium. The subpopulation of AP-2ß-positive mammary epithelial cells showed an almost complete, superimposable co-expression with GATA3 and a peculiar intense, ring-like appearing immunoreactivity for CK8/18. Confocal immunofluorescence microscopy revealed an apicobasal staining for CK8/18 in AP-2ß-positive cells, which was not seen in in AP-2ß-negative cells. Furthermore, AP-2ß-positive displayed a partial co-expression with ER and AR, but lacked expression of candidate stem cell markers CK5/14 and CD44. In summary, AP-2ß is a new luminal mammary epithelial differentiation marker, which is expressed in the GATA3-positive subpopulation of luminal epithelial cells. These AP-2ß-positive/GATA3-positive cells also show a peculiar CK8/18-expression which may indicate a previously unknown functionally specialized mammary epithelial cell population.

Nanoclusters of crystallographically aligned nanoparticles for magnetic thermotherapy: aqueous ferrofluid, agarose phantoms and ex vivo melanoma tumour assessment.

Magnetic hyperthermia is an oncological therapy where magnetic nanostructures, under a radiofrequency field, act as heat transducers increasing tumour temperature and killing cancerous cells. Nanostructure heating efficiency depends both on the field conditions and on the nanostructure properties and mobility inside the tumour. Such nanostructures are often incorrectly bench-marketed in the colloidal state and using field settings far off from the recommended therapeutic values. Here, we prepared nanoclusters composed of iron oxide magnetite nanoparticles crystallographically aligned and their specific absorption rate (SAR) values were calorimetrically determined in physiological fluids, agarose-gel-phantoms and ex vivo tumours extracted from mice challenged with B16-F0 melanoma cells. A portable, multipurpose applicator using medical field settings; 100 kHz and 9.3 kA m-1, was developed and the results were fully analysed in terms of nanoclusters' structural and magnetic properties. A careful evaluation of the nanoclusters' heating capacity in the three milieus clearly indicates that the SAR values of fluid suspensions or agarose-gel-phantoms are not adequate to predict the real tissue temperature increase or the dosage needed to heat a tumour. Our results show that besides nanostructure mobility, perfusion and local thermoregulation, the nanostructure distribution inside the tumour plays a key role in effective heating. A suppression of the magnetic material effective heating efficiency appears in tumour tissue. In fact, dosage had to be increased considerably, from the SAR values predicted from fluid or agarose, to achieve the desired temperature increase. These results represent an important contribution towards the design of more efficient nanostructures and towards the clinical translation of hyperthermia.

Quality assurance trials for Ki67 assessment in pathology.

Ki67 is a broadly used proliferation marker in surgical pathology with an obvious need for standardization to improve reproducibility of assessment. Here, we present results of the so far only existing round robin tests on Ki67, organized annually in Germany, Austria, and Switzerland from 2010 to 2015 with up to 160 participating laboratories (QuIP). In each quality assessment trial, eight probes from each breast cancer, neuroendocrine tumor, and malignant lymphoma were compiled on a tissue microarray (TMA). TMAs were stained in the participants' laboratories with antibodies and procedures also applied in their daily routine. Participating pathologists were expected to assign Ki67 values to one of four different categories for each tumor type. All local stainings and evaluations were reassessed by the organizing panel and compared to a preset standard. On average, 95% of participants reached the benchmark of over 80% concordance rates with the Ki67 category pre-established by the panel. Automatization and type of antibody did not affect the success rate. Concordance rates differed between tumor entities being highest in each tumor type with either very high or very low labeling indices. Lower rates were seen for intermediate Ki67 levels. Staining quality improved during the observation period as did inter-observer concordance with 85% of participants achieving excellent agreement (kappa > 0.8) in the first year and over 95% in 2015. In conclusion, regular external quality assurance trials have been established as a tool to improve the reproducibility and reliability of the prognostic and predictive proliferation marker Ki67.

Anticipating hyperthermic efficiency of magnetic colloids using a semi-empirical model: a tool to help medical decisions.

Magnetic hyperthermia, a modality that uses radio frequency heating assisted with single-domain magnetic nanoparticles, is becoming established as a powerful oncological therapy. Much improvement in nanomaterials development, to enhance their heating efficiency by tuning the magnetic colloidal properties, has been achieved. However, methodological standardization to accurately and univocally determine the colloidal properties required to numerically reproduce a specific heating efficiency using analytical expressions still holds. Thus, anticipating the hyperthermic performances of magnetic colloids entails high complexity due to polydispersity, aggregation and dipolar interactions always present in real materials to a greater or lesser degree. Here, by numerically simulating the experimental results and using real biomedical aqueous colloids, we analyse and compare several approaches to reproduce experimental specific absorption rate values. Then, we show that the relaxation time, determined using a representative mean activation energy consistently derived from four independent experiments accurately reproduces experimental heating efficiencies. Moreover, the so-derived relaxation time can be used to extrapolate the heating performance of the magnetic nanoparticles to the other field conditions within the framework of the linear response theory. We thus present a practical tool that may truly aid the design of medical decisions.

Measuring the noble metal and iodine composition of extracted noble metal phase from spent nuclear fuel using instrumental neutron activation analysis.

Masses of noble metal and iodine nuclides in the metallic noble metal phase extracted from spent fuel are measured using instrumental neutron activation analysis. Nuclide presence is predicted using fission yield analysis, and radionuclides are identified and the masses quantified using neutron activation analysis. The nuclide compositions of noble metal phase derived from two dissolution methods, UO2 fuel dissolved in nitric acid and UO2 fuel dissolved in ammonium-carbonate and hydrogen-peroxide solution, are compared.

[Notched-noise-BERA: methods and diagnostic use]. / Methodik und diagnostischer Stellenwert der Notched-Noise-BERA.

BACKGROUND: As Picton demonstrated with case reports in 1978, thresholds of click-evoked potentials do not match to pure tone thresholds if hearing loss differs across the test frequencies. Thus, he developed a stimulation with brief tone pips masked by a notched noise that over the years became the standard method for frequency specific threshold estimation. Currently, new technologies like auditory steady-state responses and Chirp-evoked potentials promise to overcome some disadvantages of the NN-BERA. METHODS: Thus, a systematic review about the NN-BERA was needed to further compare the competitive technologies. Literature research was performed according to the present guidelines for evidence based medicine. It was found that a meta-analysis with data pooling was impossible because of massive discrepancies of methods and subjects across the retrieved publications. RESULTS: The differences of means between pure tone thresholds and NN-BERA-thresholds were up to 12 dB. Standard deviations were 2 to 16 dB and generally higher at 0.5 und 1 kHz compared to 2 and 4 kHz. Correlations were r = 0.84 to r = 0.97. CONCLUSIONS: The NN-BERA faces a growing competition by auditory steady state potentials, chirp-evoked potentials, and distortion product otoacoustic emissions but serves still as the standard for an objective threshold estimation since it's accuracy is well evaluated and the interpretation is independent from statistical tests which accuracy is not sufficiently evaluated at present.

[The management of dysphagia -- part 2: therapy]. / Chronische Schluckstörungen. Teil 2: Therapie.

In the first part of the article we described diagnostic methods aiming to resolve the individual underlying pathomechanism of chronic swallowing disorders (dysphagia). From these, we deducted different therapeutic measures that can be applied either alone or in combination. Weakening of the upper esophageal sphincter with botulinum toxin is reserved for patients with structural stenosis or a relative hyperfunction of the sphincter. It can be tried to use the "Passy-Muir Valve" for tracheostomized patients that aspirate. Most cases benefit from a therapy that consists of specific exercises. "Restitution" relies on exercises to practice new movement patterns as well as improvement of muscle strength. "Compensation" is based on exercises to counteract structural and/or functional deficits. Through "adaptation" residual, therapy resistant disease can be alleviated through dietary planning of consistency, temperature, and nutrient content of food. In many cases it is necessary to combine "restitution", "compensation", and "adaptation".

A preclinical model for experimental chemotherapy of human head and neck cancer.

We developed a mouse model in a representative human derived head and neck cancer cell line for preclinical studies to evaluate antitumor response, tumor-free survival and host toxicity of alkylating agents, antimetabolites, platinum analogs and taxanes alone or in combination. Ninety athymic NMRI mice were inoculated with human derived oral squamous cell carcinoma cells growing on the hind paw to an average volume of 180 +/- 80 mm3. Animals were stratified according to tumor volume into 10 groups (n=6-10) and treated with ifosfamide (65 mg/kg b.w.), docetaxel (24 mg/kg b.w.), cisplatin (2 mg/kg b.w.), carboplatin (6 or 10 mg/kg b.w.), methotrexate (1 mg/kg b.w.), and fluorouracil (15 mg/kg b.w.) intravenously in single agent or combination (ifosfamide plus docetaxel or ifosfamide plus carboplatin) treatment schedules or controls. Tumor volume was measured 3 times per week for 60 days. The average tumor volume, the overall survival time and the response rates (CR, PR) of the treated animals were compared with the data obtained from untreated controls and statistically evaluated. Untreated tumors showed rapid and exponential tumor growth. Single agent therapies with ifosfamide, cisplatinum, and docetaxel lead to significant tumor regression and improved overall survival. Low dose carboplatin monotherapy induced significant tumor growth delay, but not significant tumor regression. Most impressive tumor-free survival was achieved by combination treatment with ifosfamide and docetaxel. This preclinical study demonstrates an animal model capable of differentiating various chemotherapy regimens.

Differences in chain length distribution of inulin from Cynara scolymus and Helianthus tuberosus are reflected in a transient plant expression system using the respective 1-FFT cDNAs.

A newly isolated cDNA clone, Cy3, encoding the fructan fructan 1-fructosyltransferase (1-FFT) from artichoke was expressed using tobacco protoplasts as expression system. Analysis of the inulin molecules synthesized upon incubation of protoplast extracts with a mixture of oligofructans (DP3-5) shows the production of inulins with a degree of polymerization (DP) of up to 23, whereas parallel experiments performed using a 1-FFT cDNA from Jerusalem artichoke led to the production of fructans with a DP of up to only 12. The results of in vitro fructan synthesis catalyzed by transiently expressed enzymes therefore reflect the difference of in vivo fructan composition of Jerusalem artichoke (M(DP) = 8-10) and artichoke (M(DP) = 65). These data suggest that the fructan pattern in a given species is mainly defined by the enzymatic characteristics of 1-FFT.