BackgroundRecently, 177Lu-dotatate therapy for neuroendocrine tumours has received regulatory approval. Dosimetry can be used to optimize treatment on an individual basis, but there is no international consensus as to how it should be done.The aim of this study is to determine a feasible and accurate dosimetry method to guide individualized peptide receptor radionuclide therapy (PRRT) for patients with neuroendocrine tumours.As part of a clinical trial on 177Lu-dotatate therapy, renal dosimetry was performed for all patients in each treatment cycle, using a hybrid planar-SPECT/CT method. In the present study, we use the image data acquired from 22 patients and 119 cycles and define a set of alternative treatment planning strategies, each representing a simplification in terms of image acquisition and dosimetric calculations. The results from the simplified strategies are compared to the results from the protocol-prescribed hybrid planar-SPECT/CT-based method by analysing differences both in per-cycle and total cumulative absorbed dose (AD) analyses.ResultsIn general, the SPECT-based methods gave results that were largely consistent with the protocol-specified hybrid method, both in the per-cycle and cumulative AD analyses. Notably, performing one SPECT/CT per cycle at 96 h yielded ADs that were very similar to the protocol method. The methods using planar dosimetry resulted in larger variations, as expected, while giving 4 cycles to all patients resulted in the largest inter-individual differences in cumulative AD.ConclusionsPerforming one SPECT/CT at 96 h in every treatment cycle gives sufficiently reliable dosimetric results to base individualized treatment planning on, with a reasonable demand on resources.Electronic supplementary materialThe online version of this article (10.1186/s40658-018-0210-2) contains supplementary material, which is available to authorized users.

Intranasal drug delivery is a promising approach for the delivery of drugs to the CNS, but too heterogenous, unprecise delivery methods without standardization decrease the quality of many studies in rodents. Thus, the lack of a precise and region-specific application technique for mice is a major drawback. In this study, a previously developed catheter-based refined technique was validated against the conventional pipette-based method and used to specifically reach the olfactory or the respiratory nasal regions. This study successfully demonstrated region-specific administration at the olfactory mucosa resulting in over 20% of the administered fluorescein dose in the olfactory bulbs, and no peripheral bioactivity of insulin detemir and Fc-dependent uptake of two murine IgG1 (11C7 and P3X) along the olfactory pathway to cortex and hippocampus. An scFv of 11C7 showed hardly any uptake to the CNS. Elimination was dependent on the presence of the IgG’s antigen. In summary, it was successfully demonstrated that region-specific intranasal administration via the olfactory region resulted in improved brain targeting and reduced peripheral targeting in mice. The data are discussed with regard to their clinical potential.

Strict regulation of T cell function is imperative to control adaptive immunity, and dysregulation of T cell activation can contribute to infectious and autoimmune diseases. Vasoactive intestinal peptide receptor-1 (VPAC-1), an anti-inflammatory G-protein coupled receptor, has been reported to be downregulated during T cell activation. However, the regulatory mechanisms controlling the expression of VPAC-1 in T cells are not well understood. Therefore, mouse splenic CD4 T cells were treated in complete media+/-anti-CD3 for 24h, total RNA isolated and VPAC-1 levels measured by qPCR. Surprisingly, we discovered that T cells incubated in complete media steadily upregulated VPAC-1 mRNA levels over time (24h). Importantly, CD4 T cells isolated from blood also showed elevated VPAC-1 expression compared to splenic T cells. Collectively, these data support that the vascular environment positively influences VPAC-1 mRNA expression that is negatively regulated by TCR signaling. This research was supported by a national service award (1KO1 DK064828) to G.D., the Center for Protease Research (2P20RR015566), and INBRE (P20 RR016741).

Zinc oxide nanoparticles (nZnO) are one of the most highly produced nanomaterials and are used in numerous applications including cosmetics and sunscreens despite reports demonstrating their cytotoxicity. Dissolution is viewed as one of the main sources of nanoparticle (NP) toxicity, however dissolution studies can be time-intensive to perform and complicated by issues such as particle separation from solution. Our work attempts to overcome some of these challenges by utilizing new methods using UV/vis and fluorescence spectroscopy to quantitatively assess nZnO dissolution in various biologically relevant solutions. All biological buffers tested induce rapid dissolution of nZnO. These buffers, including HEPES, MOPS, and PIPES, are commonly used in cell culture media, cellular imaging solutions and to maintain physiological pH. Additional studies using X-ray diffraction, FT-IR, X-ray photoelectron spectroscopy, ICP-MS and TEM were performed to understand how the inclusion of these non-essential media components impacts the behavior of nZnO in RPMI media. From these assessments, we demonstrate that HEPES causes increased dissolution kinetics, boosts the conversion of nZnO into zinc phosphate/carbonate and, interestingly, alters the structural morphology of the complex precipitates formed with nZnO in cell culture conditions. Cell viability experiments demonstrated that the inclusion of these buffers significantly decreases the viability of Jurkat leukemic cells when challenged with nZnO. This work demonstrates that biologically relevant buffering systems dramatically impact the dynamics of nZnO including dissolution kinetics, morphology, complex precipitate formation, and toxicity profiles.

Staphylococcus aureus causes a chronic, contagious disease of the udder, or mastitis, in dairy cows. This infection is often refractory to antibiotic treatment, and has a significant economic impact on milk production worldwide. An effective vaccine to prevent S. aureus mastitis would improve animal health, reduce antibiotic dependence and inform human vaccine approaches. The iron-regulated surface determinant A (IsdA) and clumping factor A (ClfA) are conserved S. aureus extracellular-matrix adhesins and target vaccine antigens. Here we report the results of two bovine immunogenicity trials using purified IsdA and ClfA-cholera toxin A/B chimeras (IsdA-CTA/B and ClfA-CTA/B). Cows were intranasally inoculated with IsdA-CTA/B + ClfA-CTA/B at dry off and followed for 70 days. Trial 1 utilized three groups with one or two booster doses at a total concentration of 600 or 900 μg. Trial 2 utilized two groups with one booster at a total concentration of 1200 μg. Humoral immune responses in serum and milk were examined by ELISA. Responses in serum were significant between groups and provide evidence of antigen-specific IgG induction after vaccination in both trials. Cellular proliferation was detected by flow cytometry using antigen-stimulated PBMCs from day 60 of Trial 2 and revealed an increase in CD4+ T cells from vaccinated cows. IsdA and ClfA stimulation induced IL-4 expression, but not IFN-γ or IL-17, in PBMCs from day 60 as determined by cytokine expression analysis. Opsonophagocytosis of S. aureus confirmed the functional in vitro activity of anti-IsdA antibodies from Trial 2 serum and milk. The vaccine was well tolerated and safe, and results support the potential of mucosally-delivered CTA/B chimeras to protect cows from mastitis caused by S. aureus.