Effects of daily versus weekly testing and pre-training on the assessment of neurologic impairment following diffuse traumatic brain injury in rats.

A number of test paradigms have been used to determine acute and chronic motor and cognitive deficits after experimental traumatic brain injury (TBI). Some involve daily testing of either trained or untrained animals whereas others utilize periodic testing over extended time periods. Which test paradigm is the most appropriate for the assessment of motor and cognitive deficits is, however, unclear. In the current study, we have used both daily and weekly testing in trained and untrained animals to ascertain which assessment protocol is most suited for the detection of functional deficits after diffuse TBI in rats. Animals were subjected to severe injury using the impact-acceleration model of diffuse TBI. An equal number of animals were also prepared surgically but not subject to injury (shams). The rotarod device and the Barnes Maze were used for motor and cognitive assessment respectively, with half of the animals being pre-trained on each test for 10 days prior to injury. The open field test was used to assess spontaneous exploratory activity (stress). Following injury, animals were assessed for neurologic deficits either on a daily basis (for 10 days) or a weekly basis (for 4 weeks). In trained animals, the greatest differences in neurologic outcome between injured and sham animals were observed early after injury. In contrast, in untrained animals, greatest differences between injured and sham animals were observed at later time points. Pre-injury training did not improve the rate of cognitive recover, or the rate of motor recovery in the weekly test paradigm, but did improve the rate of motor recovery in the daily assessment paradigm. Daily assessment promoted rapid functional recovery whereas weekly assessments did not significantly affect outcome in injured animals over the 4-week assessment period. Spontaneous exploratory activity was decreased after TBI and was not influenced by task exposure. These studies demonstrate that the functional assessment paradigm needs to be considered when quantifying functional deficits following diffuse TBI in rats.

Magnesium attenuates persistent functional deficits following diffuse traumatic brain injury in rats.

Although a number of studies have demonstrated that magnesium improves acute motor and cognitive outcome after traumatic brain injury, others have failed to show positive effects on cognitive outcome and none have examined persistent functional deficits. The present study shows that severe impact-acceleration induced, diffuse traumatic brain injury in rats produced profound motor and cognitive deficits that persisted for at least 4 weeks after trauma. Intravenous administration of magnesium sulfate (250 micromoles/kg) at 30 min after injury significantly improved rotarod (sensorimotor) and open field (stress/anxiety) performance, and led to a faster rate of recovery in the Barnes maze (learning). We conclude that posttraumatic magnesium administration attenuates long-term motor and cognitive deficits after traumatic brain injury, and that this improvement may include some reduction of post-traumatic stress and anxiety.

Nutrition status of primary school children in Townsville.

OBJECTIVE: Much of the ill health of Australian Indigenous populations can be attributed to diet-related diseases. Many of these diseases and the deleterious dietary choices are thought to begin in early childhood. This project therefore aimed to assess the nutritional health status of children in Townsville. It enabled the Townsville Aboriginal and Islander community to identify and redress nutrition-related issues considered important in improving the overall health status of their community. DESIGN: Baseline urinalysis, anthropometrics, general overall health assessment, dietary and exercise histories were collected. This screening was repeated annually. Diet and exercise histories were recorded biannually. SETTING: Based in three Northern Queensland health region (pre)primary schools with a high proportion of Indigenous children. RESULTS: Baseline results demonstrated that more children are overweight to obese than underweight. There was no significant difference in body mass index between Indigenous and Non-Indigenous children. Indigenous children were shown to consume less vegetable and dairy products and were significantly more likely to suffer from anaemia, iron depletion and eosinophilia than non-Indigenous children. Indigenous children were also twice as likely to have runny noses and are more than three times more likely to have skin sores. CONCLUSION: These results support that the health status of the Indigenous children is poorer than that of non-Indigenous children. They demonstrate an immediate need to implement culturally appropriate nutritional and exercise programs within the school environment to improve dietary habits and overall health. Implementation of nutritional, drinking and exercise programs may significantly improve these children's overall awareness and behaviour concerning nutrition and health.

Magnesium attenuates post-traumatic depression/anxiety following diffuse traumatic brain injury in rats.

OBJECTIVE: Magnesium (Mg) declines after traumatic brain injury (TBI), a decline believed associated with ensuing neuronal cell death and subsequent functional impairment. While Mg's effects on motor and cognitive deficits following TBI have been well studied, few studies have addressed post-traumatic depression as an outcome parameter, despite its being a major clinical problem with an incidence of between 6 and 77%. We investigated the incidence of post-traumatic depression/anxiety in an animal model of diffuse TBI, and explored the use of magnesium sulfate (MgSO(4)) as an interventional treatment. METHODS: Diffuse TBI was induced in 32 anesthetized, adult, male Sprague-Dawley rats, using the 2 m impact-acceleration model of injury. At 30 min after injury, half of the rats received 250 micromol/kg i.v. MgSO(4); the other half served as non-treated controls. Before and for 6 weeks after injury, the open-field, spontaneous activity test was used to determine post-traumatic depression/anxiety relative to pre-injury. In this test, animals are placed in a 1-meter square box with 100 squares marked on the base. The number of squares entered in a 5-min period is recorded. Incidence of post-traumatic depression/anxiety was defined as the number of animals demonstrating a reduction in spontaneous activity to less than 100 squares in 5 min. Prior to injury, rats typically entered a mean of 201 +/- 12 (SEM) squares over a 5 min observation period. RESULTS: At 1 week after injury, non-treated animals had a mean core of 62 +/- 13. The incidence of post-traumatic depression/anxiety in these animals was 61%, which is similar to that observed clinically. In contrast, animals treated with MgSO(4) had a mean activity score of 144 +/- 23 at 1 week after TBI and an incidence of depression/anxiety of less than 30%. The significant difference between groups persisted for the entire 6-week observation period. CONCLUSIONS: The improvement in post-traumatic depression/anxiety conferred by Mg adds further weight to available evidence of Mg's benefit as a neuroprotective agent after TBI.