School attendance and sport participation amongst children with chronic kidney disease: a cross-sectional analysis from the Kids with CKD (KCAD) study.

BACKGROUND: School attendance and life participation, particularly sport, is a high priority for children with chronic kidney disease (CKD). This study is aimed at assessing the association between CKD stage, sports participation, and school absences in children with CKD. METHODS: Using data from the binational Kids with CKD study (ages 6-18 years, n = 377), we performed multivariable regression to evaluate the association between CKD stage, school absences, and sports participation. RESULTS: Overall, 62% of participants played sport with the most frequent sport activities engaged in being swimming (17%) and soccer (17%). Compared to children with CKD 1-2, the incidence rate ratios (IRR) (95% CI) for sports participation amongst children with CKD 3-5, dialysis, or transplant were 0.84 (0.64-1.09), 0.59 (0.39-0.90), and 0.75 (0.58-0.96), respectively. The median (IQR) days of school absences within a four-week period were 1 day (0-1), with children on dialysis reporting the highest number of school absences (9 days (5-15)), followed by transplant recipients (2 days (1-7)), children with CKD 3-5 (1 day (0-3)), and with CKD 1-2 (1 day (0-3)). Duration of CKD modified the association between CKD stage and school absences, with children with a transplant experiencing a higher number of missed school days with increasing duration of CKD, but not in children with CKD 1-5 or on dialysis (p-interaction < 0.01). CONCLUSIONS: Children receiving dialysis and with a kidney transplant had greater school absences and played fewer sports compared to children with CKD stages 1-2. Innovative strategies to improve school attendance and sport participation are needed to improve life participation of children with CKD.

Evidence of humans in North America during the Last Glacial Maximum.

Archaeologists and researchers in allied fields have long sought to understand human colonization of North America. Questions remain about when and how people migrated, where they originated, and how their arrival affected the established fauna and landscape. Here, we present evidence from excavated surfaces in White Sands National Park (New Mexico, United States), where multiple in situ human footprints are stratigraphically constrained and bracketed by seed layers that yield calibrated radiocarbon ages between ~23 and 21 thousand years ago. These findings confirm the presence of humans in North America during the Last Glacial Maximum, adding evidence to the antiquity of human colonization of the Americas and providing a temporal range extension for the coexistence of early inhabitants and Pleistocene megafauna.

North-south dipole in winter hydroclimate in the western United States during the last deglaciation.

During the termination of the last glacial period the western U.S. experienced exceptionally wet conditions, driven by changes in location and strength of the mid-latitude winter storm track. The distribution of modern winter precipitation is frequently characterized by a north-south wet/dry dipole pattern, controlled by interaction of the storm track with ocean-atmosphere conditions over the Pacific and Atlantic Oceans. Here we show that a dipole pattern of similar geographic extent persisted and switched sign during millennial-scale abrupt climate changes of the last deglaciation, based on a new lake level reconstruction for pluvial Lake Chewaucan (northwestern U.S.), and a compilation of regional paleoclimate records. This suggests the dipole pattern is robust, and one mode may be favored for centuries, thereby creating persistent contrasting wet/dry conditions across the western U.S. The TraCE-21k climate model simulation shows an equatorward enhancement of winter storm track activity in the northeastern Pacific, favoring wet conditions in southwestern U.S. during the second half of Heinrich Stadial 1 (16.1-14.6 ka) and consistent with paleoclimate evidence. During the Bølling/Allerød (14.6-12.8 ka), the northeastern Pacific storm track contracted poleward, consistent with wetter conditions concentrated poleward toward the northwest U.S.

An oxytocin-dependent social interaction between larvae and adult C. elegans.

Oxytocin has a conserved role in regulating animal social behaviour including parental-offspring interactions. Recently an oxytocin-like neuropeptide, nematocin, and its cognate receptors have been identified in the nematode Caenorhabditis elegans. We provide evidence for a pheromone signal produced by C. elegans larvae that modifies the behaviour of adult animals in an oxytocin-dependent manner increasing their probability of leaving a food patch which the larvae are populating. This increase is positively correlated to the size of the larval population but cannot be explained by food depletion nor is it modulated by biogenic amines, which suggest it is not an aversive behaviour. Moreover, the food-leaving behaviour is conspecific and pheromone dependent: C. elegans adults respond more strongly to C. elegans larvae compared to other nematode species and this effect is absent in C. elegans daf-22 larvae which are pheromone deficient. Neurotransmitter receptors previously implicated in C. elegans foraging decisions NPR-1 and TYRA-3, for NPY-like neuropeptides and tyramine respectively, do not appear to be involved in oxytocin-dependent adult food-leaving. We conclude oxytocin signals within a novel neural circuit that regulates parental-offspring social behaviour in C. elegans and that this provides evidence for evolutionary conservation of molecular components of a parental decision making behaviour.

Evaluation of a novel delayed-type hypersensitivity assay to Candida albicans in adult and neonatal rats.

Delayed-type hypersensitivity (DTH) is a T-cell-mediated immune response that may be used for immunotoxicity testing in non-clinical species. However, in some cases DTH assays using T-dependent antigens may be confounded by the production of antibodies to the antigen. The authors have previously modified a DTH assay, initially validated in the mouse, for use in juvenile rats to assess the effect of immunosuppressive drugs on the developing rat immune system. The assay measures footpad swelling induced by subcutaneous footpad injection of Candida albicans (C. albicans) derived-chitosan in rats previously sensitized with C. albicans. Antibodies to chitosan are not produced in this model. However, considerable inter-animal variability inherent in the footpad swelling assay can make it difficult to precisely quantify the magnitude of the immune response and inhibition by immunosuppressants, particularly if complete suppression is not observed. This report describes the development of an ex vivo assay to assess DTH in rats using interferon (IFN)-γ production by splenocytes, obtained from rats sensitized with C. albicans, as the quantifiable measure of the DTH response. Adult and neonatal rats administered dexamethasone (DEX), a known immunosuppressant, exhibited immunosuppression as evidenced by a reduction in ex vivo IFNγ production from splenocytes challenged with C. albicans-derived chitosan. Current data indicate that the ex vivo based DTH assay is more sensitive than the conventional footpad swelling assay due to a lower background response and the ability to detect a response as early as post-natal day (PND) 12. The ex vivo based rat DTH assay offers a highly sensitive and quantitative alternative to the footpad swelling assay for the assessment of the immunotoxic potential of drugs. The increased sensitivity of the ex vivo DTH assay may be useful for identifying smaller changes in response to immunotoxic drugs, as well as detecting responses earlier in animal development.