Sensitivity of the early life stages of a mayfly to fine sediment and orthophosphate levels

The ecological effects of interacting stressors within lotic ecosystems have been widely acknowledged. In particular, the ecological effects of elevated fine sediment inputs and phosphate have been identified as key factors influencing faunal community structure and composition. However, while knowledge regarding adult and larval life stage responses to environmental stressors has grown, there has been very limited research on their eggs. In this study, the eggs of the mayfly Serratella ignita (Ephemerellidae: Ephemeroptera) were collected and incubated in laboratory aquaria to hatching under differing concentrations of inert suspended sediment (SS) and orthophosphate (OP), individually and in combination. Results indicate that SS and OP have greater effects on egg hatching in combination than when either were considered in isolation. SS displayed a greater effect on egg survival than OP in isolation or when OP was added to elevated SS treatments. Egg mortality in control treatments was around 6% compared to 45% in treatments with 25 mg 1⁻¹ SS and 52% in 0.3 mg 1⁻¹ OP treatments. Even relatively modest levels of each stressor (10 mg 1⁻¹ SS; 0.1 mg 1⁻¹ OP), below national legal thresholds, had significant effects on egg survival to hatching. The results support calls for legal levels of SS to be reassessed and suggest that more research is required to assess the impacts of pollution on invertebrate egg development given their different sensitivity and exposure pathways compared to other life stages

Resuscitation of Traumatic Brain Injury and Hemorrhagic Shock with Polynitroxylated Albumin, Hextend, Hypertonic Saline, and Lactated Ringer's: Effects on Acute Hemodynamics, Survival, and Neuronal Death in Mice

Outcome after traumatic brain injury (TBI) is worsened by hemorrhagic shock (HS), but the optimal resuscitation approach is unclear. In particular, treatment of TBI patients with colloids remains controversial. We hypothesized that resuscitation with the colloids polynitroxylated albumin (PNA) or Hextend (HEX) is equal or superior to resuscitation with the crystalloids hypertonic (3%) saline (HTS) or lactated Ringer's solution (LR) after TBI plus HS in mice. C57/BL6 mice (n = 30) underwent controlled cortical impact (CCI) and 90 min of volume-controlled HS (2 mL/100 g). The mice were randomized to resuscitation with LR, HEX, HTS, or PNA, followed by 30 min of test fluid administration targeting a mean arterial pressure (MAP) of >50 mm Hg. Shed blood was re-infused to target a MAP >70 mm Hg. At 7 days post-insult, hippocampal neuron counts were assessed in hematoxylin and eosin–stained sections to quantify neuronal damage. Prehospital MAP was higher, and prehospital and total fluid requirements were lower in the PNA and HEX groups (p < 0.05 versus HTS or LR). Also, 7-day survival was highest in the PNA group, but was not significantly different than the other groups. Ipsilateral hippocampal CA1 and CA3 neuron loss did not differ between groups. We conclude that the colloids PNA and HEX exhibited more favorable effects on acute resuscitation parameters than HTS or LR, and did not increase hippocampal neuronal death in this model