Natural history of blood glucose within the first 48 hours after ischemic stroke.

BACKGROUND: Despite suggestions that glucose levels rise after stroke before falling within a few hours, the natural history and determinants of this phenomenon remain unclear. We aimed to better characterize the time course of changes in glucose levels after ischemic stroke and to identify factors that affect poststroke glycemia. METHODS: Patients with ischemic stroke without previously diagnosed diabetes had blood glucose measured at least 4-hourly until 48 hours poststroke. The relationship between baseline factors, such as the NIH Stroke Scale, and blood glucose was assessed with mixed-effects models. The behavior of glucose over time was modeled in the whole cohort, and for the cohort partitioned into two around an admission glucose of 6.0 mmol/L. RESULTS: In the cohort of 124 patients the mean glucose was 6.6 mmol/L throughout the period of monitoring, with no change over time. Mixed-effects models identified more severe stroke and glucose-lowering therapy to be associated with higher poststroke glucose levels. When the cohort was partitioned, the mean glucose of those below 6.0 mmol/L at admission increased and the mean glucose of those above 6.0 mmol/L at admission decreased to the overall mean. CONCLUSIONS: Mean glucose levels remain static in patients with ischemic stroke without diabetes until at least 48 hours poststroke. Serial glucose levels are higher in patients with more severe stroke. Initially high or low mean glucose recordings exhibit regression to the mean over time, a change which may merely be a statistical phenomenon without necessarily indicating resolution of abnormal glycemia.

Visual detection, pattern discrimination and visual acuity in 14 strains of mice.

Based on the procedure of Prusky et al. (2000, Vision Research, 40, 2201-2209), we used a computer-based, two-alternative swim task to evaluate visual detection, pattern discrimination and visual acuity in 14 strains of mice from priority groups A and B of the JAX phenome project (129S1/SvImJ, A/J, AKR/J, BALB/cByJ, BALB/cJ, C3H/HeJ, C57BL/6J, CAST/Ei, DBA/2J, FVB/NJ, MOLF/Ei, SJL/J, SM/J and SPRET/Ei). Each mouse was tested for eight trials/day for 8 days on each of the three tests. There was a significant strain difference in visual ability in all three tests. Mice with reported normal vision (129S1/SvImJ, C57BL/6J and DBA/2J) and one albino strain (AKR/J) performed very well in these tasks. The other albino strains (A/J, BALB/cByJ and BALB/cJ) took longer to learn the tasks than mice with normal vision and did not reach the criterion of 70% correct. Mice with retinal degeneration (C3H/HeJ, FVB/NJ, MOLF/Ei and SJL/J) performed only at chance levels as did the three strains with unknown visual abilities (CAST/Ei, SM/J and SPRET/Ei). Because many behavioral tasks for rodents rely on visual cues, we suggest that the visual abilities of mice should be evaluated before they are tested in commonly used visuo-spatial learning and memory tasks.