Multisystem inflammatory syndrome in children characterized by enhanced antigen-specific T-cell expression of cytokines and its reversal following recovery.

Background: Multisystem inflammatory syndrome (MIS) in children is considered to be a post-infectious complication of COVID-19. T-cell responses in children with this condition have not been well-studied. Methods: We aimed to study the immune responses in children with MIS in comparison to children with acute COVID-19 and children with other infections. Whole blood was stimulated with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-specific antigens and flow cytometry was performed to examine CD4+ and CD8+ T-cell responses. Results: Children with MIS had higher frequencies of CD4+ and CD8+ T cells expressing cytokines at baseline and upon SARS-CoV-2 antigen-specific stimulation in comparison to children with COVID-19 and/or other infections. Children with COVID-19 also exhibited higher frequencies of CD4+ and CD8+ T cells expressing cytokines at baseline and upon SARS-CoV-2 antigen-specific stimulation in comparison to children with other infections. At 6-9 months following treatment and recovery, this enhanced response against SARS-CoV-2 antigens was down modulated in children with MIS. Conclusion: Our study, therefore, provides evidence of enhanced activation of CD4+ and CD8+ T-cell responses in children with MIS and reversal following recovery.

Motor performance and functional mobility in children with specific learning disabilities.

INTRODUCTION: Limitations in motor performances among children with specific learning disabilities (SLD) can lead to impaired functional skills. Thus, this study aimed to determine the level of motor performances and functional mobility, and the influence of motor performances on the functional mobility in children with SLD. METHODS: A cross-sectional study was conducted among 148 children with SLD and their caregivers. The evaluation consisted of the Movement Assessment Battery for Children-2 (MABC-2) and the Functional Mobility domain from Pediatric Evaluation of Disability Inventory-Computer Adaptive Test (PEDI-CAT). The level of motor performances and functional mobility were determined. A linear regression was then conducted to assess the influence of motor performances that could be accounted for functional mobility scores. RESULTS: More than half of the children with SLD showed motor performance difficulty in manual dexterity subscale (54.7%). For functional mobility, the mean standard T-score indicated an average level of capability (49.49±15.96). A regression analysis revealed that both manual dexterity and balance were significant predictors for functional mobility. According to the regression coefficients, manual dexterity (B=1.37, ß=0.303, sr2=0.077) was found to be a stronger predictor compared to balance (B=0.85, ß=0.178, sr2=0.028). CONCLUSION: Manual dexterity was found to influence functional mobility among children with SLD. Therefore, fine motor skills intervention for children with SLD should emphasize on manual dexterity training. Future studies that involve dual tasks and inclusion of typical children would give useful additional information on motor performances issues in children with SLD.

Durable sensitization of hormone receptors during differentiation in regenerating planarians by treatment with homologous or analogous hormone molecules.

Hormonal (dopamine, epinephrine) treatment of planarians during total regeneration (sensitizing treatment) resulted in amplification of the receptors, which accounted for an increased response to later hormone exposure (provocative treatment). While not presensitized specimens showed an identical increase of glucose uptake upon provocative treatment with either hormone, dopamine proved to be more active than epinephrine regardless of homologous or analogous presensitization. The glucose-uptake-enhancing effect of dopamine was independent of the presensitizing dose level, whereas that of epinephrine was not, having increased as the presensitizer concentration was elevated. The experimental observations indicate that the hormone receptors may become modified, i.e. durably amplified, during the differentiation stage and that exposure of the differentiating receptor to a structurally dissimilar, analogous molecule may result not only in deformation, but also in amplification of the receptor.

The effect of sympathicomimetic agents on carbohydrate metabolism of planaria.

Epinephrine, ephedrine, dopamine and isoproterenol considerably influence carbohydrate utilization in planaria. Dopamine alone and in combination is the most potent, while ephedrine the least effective in this respect. The finding of increased responses to combined treatment supports the view of the existence of different receptor sites for the sympathicomimetic drugs. The results substantiate conclusions concerning the phylogenesis of hormone receptors.

Analysis of the progress of hormone-receptor amplification during differentiation in regenerating planarians.

Planarians developing from isolated regenerates, when pretreated with epinephrine at different periods of their second regeneration, show a higher rate of sugar uptake than the controls, which were not treated with epinephrine. The hormone receptor development can be influenced most effectively by pretreatments performed during the 1--3 and 6--9 day periods, though some effect can be evoked at any time in the course of the second regeneration. The head regenerates developing from the anterior end of the original midpiece (and regenerating tails the second time, B1) were found to be most sensitive, while the similar regenerates developing from the hindpiece of the original planarian (C) showed the weakest reactivity. The experiments provide further evidence that the hormone receptors' activity can be amplified in the course of regenerative development, leading thus--at a later stage--to a more intense sugar uptake response of the cells.

Effects of epinephrine, glucagon and insulin on glucose metabolism of planaria.

Epinephrine and insulin increased glucose uptake in Planaria, but epinephrine did so to a much grater extent. Glucagon proved to be without effect. The experiments support earlier results according to which in unicellular and invertebrate organisms membrane patterns can be found, which are similar to those of higher organisms and behave like receptors.