Axillary Lymph Node Uptake on 18F-FDG PET/CT after COVID-19 Vaccination: A Direct Comparison Study with Influenza Vaccination.

Objectives: To compare vaccinated-side axillary lymph node uptake on 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) after coronavirus disease-2019 (COVID-19) and influenza vaccination. Methods: We retrospectively analyzed 177 patients who underwent 18F-FDG PET/CT after COVID-19 or influenza vaccination. We compared the uptake of the vaccinated-side axillary lymph nodes of 109 COVID-19 vaccinated patients with those of a lot of influenza-vaccinated patients. We also compared the uptake between 66 patients who received the first COVID-19 vaccination with 43 who received the second COVID-19 vaccination. Results: 18F-FDG-avid axillary lymph nodes on the vaccinated side were significantly more frequently observed in the COVID-19 group (45%) than in the influenza group (19%) (p<0.001). When the interval between vaccination to PET/CT was within 7 days, there was no significant difference in the frequency of 18F-FDG-avid vaccinated-side axillary lymph nodes between the groups (COVID-19 group: 41% vs. influenza group: 45%, p=0.724). When the interval was over 7 days, 18F-FDG-avid lymph nodes were much more frequent in the COVID-19 group (47%) than in the influenza group (7%) (p<0.001). Comparing the first and second COVID-19 groups, 18F-FDG-avid lymph nodes were more frequent in the second vaccination group than in the first vaccination group, but the difference was not significant. Conclusion: 18F-FDG-avid vaccinated-side axillary lymph nodes were more frequently observed in the COVID-19 group than in the influenza group. In the case of the COVID-19 vaccine, a delay of 18F-FDG PET/CT examination is recommended by a longer interval from vaccination than in the influenza vaccine.

A novel cytoskeletal action of xylosides.

Proteoglycan glycosaminoglycan (GAG) chains are attached to a serine residue in the protein through a linkage series of sugars, the first of which is xylose. Xylosides are chemicals which compete with the xylose at the enzyme xylosyl transferase to prevent the attachment of GAG chains to proteins. These compounds have been employed at concentrations in the millimolar range as tools to study the role of GAG chains in proteoglycan function. In the course of our studies with xylosides, we conducted a dose-response curve for xyloside actions on neural cells. To our surprise, we found that concentrations of xylosides in the nanomolar to micromolar range had major effects on cell morphology of hippocampal neurons as well as of Neuro2a cells, affecting both actin and tubulin cytoskeletal dynamics. Such effects/morphological changes were not observed with higher xyloside concentrations. We found a dose-dependent alteration of GAG secretion by Neuro2a cells; however, concentrations of xylosides which were effective in altering neuronal morphology did not cause a large change in the rate of GAG chain secretion. In contrast, both low and high concentrations of xylosides altered HS and CS composition. RNAseq of treated cells demonstrated alterations in gene expression only after treatment with millimolar concentration of xylosides that had no effect on cell morphology. These observations support a novel action of xylosides on neuronal cells.

Brain abnormalities in children with attention-deficit/hyperactivity disorder assessed by multi-delay arterial spin labeling perfusion and voxel-based morphometry.

PURPOSE: To obtain an understanding of the correlation between hemodynamic differences and morphological changes as well as potential sex differences in children with ADHD using multi-delay pseudo-continuous arterial spin labeling (pCASL) imaging and voxel-based morphometry (VBM), especially given that previous findings are limited for girls. MATERIALS AND METHODS: We recruited 23 children with ADHD (mean age, 8.3 years; 19 boys; 4 girls) and 24 children without ADHD (mean age, 9.1 years; 13 boys; 11 girls) as controls. All participants underwent 3D multi-delay pCASL and T1-weighted imaging. The voxel-based statistical parameter mapping (SPM) method was used for group-wise comparisons. RESULTS: Compared with controls, children with ADHD exhibited decreased regional cerebral blood flow (rCBF) and gray matter volume (GMV) in the left middle frontal gyrus and left postcentral gyrus. Analysis by sex revealed reduced rCBF and GMV in the left lingual gyrus and left inferior occipital gyrus in boys with ADHD versus controls and increased rCBF and GMV in the left superior frontal gyrus in girls with ADHD. CONCLUSION: Although our results are preliminary because of small sample sizes, several brain regions exhibit changes in both cerebral perfusion and GMV in the same direction in patients with ADHD, with boys with ADHD showing decreased activity and girls with ADHD displaying increased activity in the fronto-parietal cortices.