Impact of stroke co-morbidities on cortical collateral flow following ischaemic stroke.

Acute hyperglycaemia and chronic hypertension worsen stroke outcome but their impact on collateral perfusion, a determinant of penumbral life span, is poorly understood. Laser-speckle contrast imaging (LSCI) was used to determine the influence of these stroke comorbidities on cortical perfusion after permanent middle cerebral artery occlusion (pMCAO) in spontaneously hypertensive stroke prone rats (SHRSP) and normotensive Wistar rats. Four independent studies were conducted. In animals without pMCAO, cortical perfusion remained stable over 180 min. Following pMCAO, cortical perfusion was markedly reduced at 30 min then gradually increased, via cortical collaterals, over the subsequent 3.5 h. In the contralateral non-ischaemic hemisphere, perfusion did not change over time. Acute hyperglycaemia (in normotensive Wistar) and chronic hypertension (SHRSP) attenuated the restoration of cortical perfusion after pMCAO. Inhaled nitric oxide did not influence cortical perfusion in SHRSP following pMCAO. Thus, hyperglycaemia at the time of arterial occlusion or pre-existing hypertension impaired the dynamic recruitment of cortical collaterals after pMCAO. The impairment of collateral recruitment may contribute to the detrimental effects these comorbidities have on stroke outcome.

Hyperglycaemia does not increase perfusion deficits after focal cerebral ischaemia in male Wistar rats.

BACKGROUND: Hyperglycaemia is associated with a worse outcome in acute ischaemic stroke patients; yet the pathophysiological mechanisms of hyperglycaemia-induced damage are poorly understood. We hypothesised that hyperglycaemia at the time of stroke onset exacerbates ischaemic brain damage by increasing the severity of the blood flow deficit. METHODS: Adult, male Wistar rats were randomly assigned to receive vehicle or glucose solutions prior to permanent middle cerebral artery occlusion. Cerebral blood flow was assessed semi-quantitatively either 1 h after middle cerebral artery occlusion using 99mTc-D, L-hexamethylpropyleneamine oxime (99mTc-HMPAO) autoradiography or, in a separate study, using quantitative pseudo-continuous arterial spin labelling for 4 h after middle cerebral artery occlusion. Diffusion weighted imaging was performed alongside pseudo-continuous arterial spin labelling and acute lesion volumes calculated from apparent diffusion coefficient maps. Infarct volume was measured at 24 h using rapid acquisition with refocused echoes T2-weighted magnetic resonance imaging. RESULTS: Glucose administration had no effect on the severity of ischaemia when assessed by either 99mTc-HMPAO autoradiography or pseudo-continuous arterial spin labelling perfusion imaging. In comparison to the vehicle group, apparent diffusion coefficient-derived lesion volume 2-4 h post-middle cerebral artery occlusion and infarct volume 24 h post-middle cerebral artery occlusion were significantly greater in the glucose group. CONCLUSIONS: Hyperglycaemia increased acute lesion and infarct volumes but there was no evidence that the acute blood flow deficit was exacerbated. The data reinforce the conclusion that the detrimental effects of hyperglycaemia are rapid, and that treatment of post-stroke hyperglycaemia in the acute period is essential but the mechanisms of hyperglycaemia-induced harm remain unclear.

Implementing Resistance Training in Secondary Schools: A Cluster Randomized Controlled Trial.

PURPOSE: Guidelines recommend that young people engage in muscle-strengthening activities on at least 3 d·wk. The purpose of this study was to examine the effect of a school-based intervention focused on resistance training (RT) for adolescents. METHODS: The "Resistance Training for Teens" intervention was evaluated using a cluster-randomized, controlled trial with 607 adolescents (50.1% girls; 14.1 ± 0.5 yr) from 16 secondary schools. Teachers were trained to deliver the intervention, which included the following: (i) an interactive student seminar; (ii) a structured physical activity program, focused on RT; (iii) lunchtime fitness sessions; and (iv) Web-based smartphone apps. The primary outcome was muscular fitness (MF) and secondary outcomes included body mass index, RT skill competency, flexibility, physical activity, self-efficacy, and motivation. Assessments were conducted at baseline, 6 months (postprogram; primary end point), and 12 months (follow-up). Outcomes were assessed using linear mixed models, with three potential moderators tested using interaction terms (and subgroup analyses where appropriate). RESULTS: For the primary outcome (MF), a group-time effect was observed at 6 months for the upper body (2.0 repetitions; 95% confidence interval (CI), 0.8-3.2), but not the lower body (-1.4 cm; 95% CI, -4.7-1.9). At 6 months, there were intervention effects for RT skill competency and self-efficacy, but no other secondary outcomes. Effects for upper body MF and RT skill competency were sustained at 12 months. Despite overall no effect for body mass index, there was a group-time effect at 12 months among students who were overweight/obese at baseline (-0.55 kg·m; 95% CI, -1.01 to -0.08). CONCLUSIONS: The school-based RT intervention resulted in immediate and sustained improvements in upper body MF and RT skill competency, demonstrating an effective and scalable approach to delivering RT within secondary schools.

Chronic photoperiod disruption does not increase vulnerability to focal cerebral ischemia in young normotensive rats.

Photoperiod disruption, which occurs during shift work, is associated with changes in metabolism or physiology (e.g. hypertension and hyperglycaemia) that have the potential to adversely affect stroke outcome. We sought to investigate if photoperiod disruption affects vulnerability to stroke by determining the impact of photoperiod disruption on infarct size following permanent middle cerebral artery occlusion. Adult male Wistar rats (210-290 g) were housed singly under two different light/dark cycle conditions ( n = 12 each). Controls were maintained on a standard 12:12 light/dark cycle for nine weeks. For rats exposed to photoperiod disruption, every three days for nine weeks, the lights were switched on 6 h earlier than in the previous photoperiod. T2-weighted magnetic resonance imaging was performed at 48 h after middle cerebral artery occlusion. Disruption of photoperiod in young healthy rats for nine weeks did not alter key physiological variables that can impact on ischaemic damage, e.g. blood pressure and blood glucose immediately prior to middle cerebral artery occlusion. There was no effect of photoperiod disruption on infarct size after middle cerebral artery occlusion. We conclude that any potentially adverse effect of photoperiod disruption on stroke outcome may require additional factors such as high fat/high sugar diet or pre-existing co-morbidities.

An atypical role for the myeloid receptor Mincle in central nervous system injury.

The C-type lectin Mincle is implicated in innate immune responses to sterile inflammation, but its contribution to associated pathologies is not well understood. Herein, we show that Mincle exacerbates neuronal loss following ischemic but not traumatic spinal cord injury. Loss of Mincle was beneficial in a model of transient middle cerebral artery occlusion but did not alter outcomes following heart or gut ischemia. High functional scores in Mincle KO animals using the focal cerebral ischemia model were accompanied by reduced lesion size, fewer infiltrating leukocytes and less neutrophil-derived cytokine production than isogenic controls. Bone marrow chimera experiments revealed that the presence of Mincle in the central nervous system, rather than recruited immune cells, was the critical regulator of a poor outcome following transient middle cerebral artery occlusion. There was no evidence for a direct role for Mincle in microglia or neural activation, but expression in a subset of macrophages resident in the perivascular niche provided new clues on Mincle's role in ischemic stroke.

A school-based intervention incorporating smartphone technology to improve health-related fitness among adolescents: rationale and study protocol for the NEAT and ATLAS 2.0 cluster randomised controlled trial and dissemination study.

INTRODUCTION: Physical inactivity has been described as a global pandemic. Interventions aimed at developing skills in lifelong physical activities may provide the foundation for an active lifestyle into adulthood. In general, school-based physical activity interventions targeting adolescents have produced modest results and few have been designed to be 'scaled-up' and disseminated. This study aims to: (1) assess the effectiveness of two physical activity promotion programmes (ie, NEAT and ATLAS) that have been modified for scalability; and (2) evaluate the dissemination of these programmes throughout government funded secondary schools. METHODS AND ANALYSIS: The study will be conducted in two phases. In the first phase (cluster randomised controlled trial), 16 schools will be randomly allocated to the intervention or a usual care control condition. In the second phase, the Reach, Effectiveness, Adoption, Implementation and Maintenance (Re-AIM) framework will be used to guide the design and evaluation of programme dissemination throughout New South Wales (NSW), Australia. In both phases, teachers will be trained to deliver the NEAT and ATLAS programmes, which will include: (1) interactive student seminars; (2) structured physical activity programmes; (3) lunch-time fitness sessions; and (4) web-based smartphone apps. In the cluster RCT, study outcomes will be assessed at baseline, 6 months (primary end point) and 12-months. Muscular fitness will be the primary outcome and secondary outcomes will include: objectively measured body composition, cardiorespiratory fitness, flexibility, resistance training skill competency, physical activity, self-reported recreational screen-time, sleep, sugar-sweetened beverage and junk food snack consumption, self-esteem and well-being. ETHICS AND DISSEMINATION: This study has received approval from the University of Newcastle (H-2014-0312) and the NSW Department of Education (SERAP: 2012121) human research ethics committees. This study is funded by the Australian Research Council (FT140100399) and the NSW Department of Education. TRIAL REGISTRATION NUMBER: ACTRN12615000360516; Pre-results.

Correction: Corticospinal and Reticulospinal Contacts on Cervical Commissural and Long Descending Propriospinal Neurons in the Adult Rat Spinal Cord; Evidence for Powerful Reticulospinal Connections.

[This corrects the article DOI: 10.1371/journal.pone.0152094.].

Correction: Is Remodelling of Corticospinal Tract Terminations Originating in the Intact Hemisphere Associated with Recovery following Transient Ischaemic Stroke in the Rat?

[This corrects the article DOI: 10.1371/journal.pone.0152176.].

Is Remodelling of Corticospinal Tract Terminations Originating in the Intact Hemisphere Associated with Recovery following Transient Ischaemic Stroke in the Rat?

Following large strokes that encompass the cerebral cortex, it has been suggested that the corticospinal tract originating from the non-ischaemic hemisphere reorganises its pattern of terminal arborisation within the spinal cord to compensate for loss of function. However many strokes in humans predominantly affect subcortical structures with minimal involvement of the cerebral cortex. The aim of the present study was to determine whether remodelling of corticospinal terminals arising from the non-ischaemic hemisphere was associated with spontaneous recovery in rats with subcortical infarcts. Rats were subjected to transient middle cerebral artery occlusion or sham surgery and 28 days later, when animals exhibited functional recovery, cholera toxin b subunit was injected into the contralesional, intact forelimb motor cortex in order to anterogradely label terminals within cervical spinal cord segments. Infarcts were limited to subcortical structures and resulted in partial loss of corticospinal tract axons from the ischaemic hemisphere. Quantitative analysis revealed there was no significant difference in the numbers of terminals on the contralesional side of the spinal grey matter between ischaemic and sham rats. The results indicate that significant remodelling of the corticospinal tract from the non-ischaemic hemisphere is not associated with functional recovery in animals with subcortical infarcts.

Corticospinal and Reticulospinal Contacts on Cervical Commissural and Long Descending Propriospinal Neurons in the Adult Rat Spinal Cord; Evidence for Powerful Reticulospinal Connections.

Descending systems have a crucial role in the selection of motor output patterns by influencing the activity of interneuronal networks in the spinal cord. Commissural interneurons that project to the contralateral grey matter are key components of such networks as they coordinate left-right motor activity of fore and hind-limbs. The aim of this study was to determine if corticospinal (CST) and reticulospinal (RST) neurons make significant numbers of axonal contacts with cervical commissural interneurons. Two classes of commissural neurons were analysed: 1) local commissural interneurons (LCINs) in segments C4-5; 2) long descending propriospinal neurons (LDPNs) projecting from C4 to the rostral lumbar cord. Commissural interneurons were labelled with Fluorogold and CST and RST axons were labelled by injecting the b subunit of cholera toxin in the forelimb area of the primary somatosensory cortex or the medial longitudinal fasciculus respectively. The results show that LCINs and LDPNs receive few contacts from CST terminals but large numbers of contacts are formed by RST terminals. Use of vesicular glutamate and vesicular GABA transporters revealed that both types of cell received about 80% excitatory and 20% inhibitory RST contacts. Therefore the CST appears to have a minimal influence on LCINs and LDPNs but the RST has a powerful influence. This suggests that left-right activity in the rat spinal cord is not influenced directly via CST systems but is strongly controlled by the RST pathway. Many RST neurons have monosynaptic input from corticobulbar pathways therefore this pathway may provide an indirect route from the cortex to commissural systems. The cortico-reticulospinal-commissural system may also contribute to functional recovery following damage to the CST as it has the capacity to deliver information from the cortex to the spinal cord in the absence of direct CST input.

Preventing obesity among Brazilian adolescent girls: Six-month outcomes of the Healthy Habits, Healthy Girls-Brazil school-based randomized controlled trial.

BACKGROUND: School-based trials to prevent and reduce prevalence of pediatric obesity in low-income countries are necessary. In Brazil, addressing adolescent obesity is a public health priority. OBJECTIVE: To evaluate the impact of a group randomized controlled trial involving a 6-month multicomponent school-based obesity prevention program targeting adolescent girls. METHODS: The Healthy Habits, Healthy Girls-Brazil program recruited participants (n=253; 16.05±0.05 years) from ten eligible public technical schools in São Paulo, Brazil. The program was adapted from an Australian intervention study, which is based on the Social Cognitive Theory. The primary outcome measure was body mass index (BMI), and secondary outcomes included BMI z score, waist circumference, and various sedentary and dietary health-related behaviours. RESULTS: Although changes in BMI were not statistically significant, differences favored the intervention group (adjusted mean difference, -0.26kg/m(2),se SE=0.018, p=0.076). Statistically significant intervention effects were found for waist circumference (-2.28cm; p=, p=0.01), computer screen time on the weekends (0.63h/day, p; p=0.02), total sedentary activities on the weekends (-0.92h/day, p<0.01), and vegetable intake (1.16servings/day, p=0.01). CONCLUSION: These findings provide some evidence for the benefit of a school-based intervention to prevent unhealthy weight gain in adolescent girls living in low-income communities.

Social cognitive mediators of dietary behavior change in adolescent girls.

OBJECTIVES: To examine potential mediators of adolescent girls' dietary behavior change in the Nutrition and Enjoyable Activity for Teen Girls (NEAT Girls) intervention for obesity prevention. METHODS: Participants were 294 adolescent girls attending 12 secondary schools located in low-income communities of New South Wales, Australia. Hypothesized social cognitive mediators of dietary behavior change were assessed using valid and reliable scales. RESULTS: The intervention effects on dietary outcomes and hypothesized mediators were not statistically significant. However, changes in hypothesized mediators were associated with changes in key dietary behaviors. CONCLUSIONS: Continued research is needed to examine effective strategies for improving dietary outcomes in youth, and to explore alternative theoretical mechanisms of dietary behavior change.

A novel 18F-labelled high affinity agent for PET imaging of the translocator protein.

The translocator protein (TSPO) is an important target for imaging focal neuroinflammation in diseases such as brain cancer, stroke and neurodegeneration, but current tracers for non-invasive imaging of TSPO have important limitations. We present the synthesis and evaluation of a novel 3-fluoromethylquinoline-2-carboxamide, AB5186, which was prepared in eight steps using a one-pot two component indium(iii)-catalysed reaction for the rapid and efficient assembly of the 4-phenylquinoline core. Biological assessment and the implementation of a physicochemical study showed AB5186 to have low nanomolar affinity for TSPO, as well as optimal plasma protein binding and membrane permeability properties. Generation of [18F]-AB5186 through 18F incorporation was achieved in good radiochemical yield and subsequent in vitro and ex vivo autoradiography revealed the ability of this compound to bind with specificity to TSPO in mouse glioblastoma xenografts. Initial positron emission tomography imaging of a glioma bearing mouse and a healthy baboon support the potential for [18F]-AB5186 use as a radiotracer for non-invasive TSPO imaging in vivo.

Assessment of [125I]WYE-230949 as a novel histamine H3 receptor radiopharmaceutical.

Histamine H3 receptor therapeutics have been proposed for several diseases such as schizophrenia, attention deficit hyperactivity disorder, Alzheimer's disease and obesity. We set out to evaluate the novel compound, [125I]WYE-230949, as a potential radionuclide imaging agent for the histamine H3 receptor in brain. [125I]WYE-230949 had a high in vitro affinity for the rat histamine H3 receptor (Kd of 6.9 nM). The regional distribution of [125I]WYE-230949 binding sites in rat brain, demonstrated by in vitro autoradiography, was consistent with the known distribution of the histamine H3 receptor. Rat brain uptake of intravenously injected [125I]WYE-230949 was low (0.11 %ID/g) and the ratio of specific: non-specific binding was less than 1.4, as determined by ex vivo autoradiography. In plasma, metabolism of [125I]WYE-230949 into a less lipophilic species occurred, such that less than 38% of the parent compound remained 30 minutes after injection. Brain uptake and metabolism of [125I]WYE-230949 were increased and specific binding was reduced in anaesthetised compared to conscious rats. [125I]WYE230949 is not a potential radiotracer for imaging rat histamine H3 receptors in vivo due to low brain uptake, in vivo metabolism of the parent compound and low specific binding.

Amyloid imaging with carbon 11-labeled Pittsburgh compound B for traumatic brain injury.

OBJECTIVES: To image amyloid deposition in patients with traumatic brain injury (TBI) using carbon 11-labeled Pittsburgh Compound B ([11C]PiB) positron emission tomography (PET) and to validate these findings using tritium-labeled PiB ([3H]PiB) autoradiography and immunocytochemistry in autopsy-acquired tissue. DESIGN, SETTING, AND PARTICIPANTS: In vivo PET at tertiary neuroscience referral center and ex vivo immunocytochemistry of autopsy-acquired brain tissue from a neuropathology archive. [11C]PiB PET was used to image amyloid deposition in 11 controls (median [range] age, 35 [24-60] years) and in 15 patients (median [range] age, 33 [21-50] years) between 1 and 361 days after a TBI. [3H]PiB autoradiography and immunocytochemistry for ß-amyloid (Aß) and ß-amyloid precursor protein in brain tissue were obtained from separate cohorts of 16 patients (median [range] age, 46 [21-70] years) who died between 3 hours and 56 days after a TBI and 7 controls (median [range] age, 61 [29-71] years) who died of other causes. MAIN OUTCOMES AND MEASURES: We quantified the [11C]PiB distribution volume ratio and standardized uptake value ratio in PET images. The distribution volume ratio and the standardized uptake value ratio were measured in cortical gray matter, white matter, and multiple cortical and white matter regions of interest, as well as in striatal and thalamic regions of interest. We examined [3H]PiB binding and Aß and ß-amyloid precursor protein immunocytochemistry in autopsy-acquired brain tissue. RESULTS: Compared with the controls, the patients with TBI showed significantly increased [11C]PiB distribution volume ratios in cortical gray matter and the striatum (corrected P < .05 for both), but not in the thalamus or white matter. Increases in [11C]PiB distribution volume ratios in patients with TBI were seen across most cortical subregions, were replicated using comparisons of standardized uptake value ratios, and could not be accounted for by methodological confounders. Autoradiography revealed [3H]PiB binding in neocortical gray matter, in regions where amyloid deposition was demonstrated by immunocytochemistry; white matter showed Aß and ß-amyloid precursor protein by immunocytochemistry, but no [3H]PiB binding. No plaque-associated amyloid immunoreactivity or [3H]PiB binding was seen in cerebellar gray matter in autopsy-acquired tissue from either controls or patients with TBI, although 1 sample of cerebellar tissue from a patient with TBI showed amyloid angiopathy in meningeal vessels. CONCLUSIONS AND RELEVANCE: [11C]PiB shows increased binding following TBI. The specificity of this binding is supported by neocortical [3H]PiB binding in regions of amyloid deposition in the postmortem tissue of patients with TBI. [11C]PiB PET could be valuable in imaging amyloid deposition following TBI.

12 month changes in dietary intake of adolescent girls attending schools in low-income communities following the NEAT Girls cluster randomized controlled trial.

Poor dietary habits and obesity are more prevalent in lower socio-economic status (SES) communities. The NEAT Girls cluster randomized controlled trial was a school-based obesity prevention program targeting adolescent girls in low SES schools in NSW, Australia. The aim was to evaluate the 12-month impact of key nutrition program messages on dietary intake and food behaviors. Diet was assessed using a validated semi-quantitative food frequency questionnaire (FFQ). Individual foods were categorized into nutrient-dense or energy-dense, nutrient-poor food groups and the percentage contribution to total energy intake calculated. Participants were aged 13.2±0.5years (n=330). There were no statistically significant group-by-time effects for dietary intake or food related behaviors, with 12-month trends suggesting more intervention group girls had improved water intakes (59% consuming⩽three glasses per day to 54% at 12 months vs. 50% to 61% in controls, p=0.052), with a greater proportion consuming < one sweetened beverage per day (24-41% vs. 34-37% in controls, p=0.057). Further research including more intensive nutrition intervention strategies are required to evaluate whether dietary intake in adolescent girls attending schools in low SES communities can be optimized.

Exploring changes in physical activity, sedentary behaviors and hypothesized mediators in the NEAT girls group randomized controlled trial.

OBJECTIVE: To evaluate the impact of a 12-month school-based multi-component program on adolescent girls' physical activity and sedentary behaviors, and hypothesized mediators of physical activity behavior change. DESIGN: Group randomized controlled trial with 12-month follow-up. METHODS: The intervention, guided by Social Cognitive Theory, involved 357 adolescent girls (13.2 ± 0.5 years) from 12 secondary schools (6 intervention schools, 6 control schools) in low-income communities in the Hunter and Central Coast regions of New South Wales, Australia. The intervention included enhanced school sport, lunchtime physical activity sessions, interactive seminars, student handbooks, nutrition workshops, pedometers, parent newsletters and text messages to encourage physical activity and healthy eating, and a decrease in sedentary behavior. Outcomes were assessed at baseline and 12-months and included: physical activity (accelerometers), sedentary behaviors (questionnaire and accelerometers), and social-cognitive mediators of physical activity (questionnaire). RESULTS: There were significant between group differences in favor of the intervention group for self-reported recreational computer use (-26.0 min; 95% CI, -46.9 to -5.1), and sedentary activities summed (-56.4 min; 95% CI, -110.1 to -2.7), however objective sedentary behavior showed no differences. There were no group-by-time effects for any of the physical activity outcomes or hypothesized mediators. CONCLUSIONS: A school-based intervention tailored for adolescent girls from schools located in low-income communities significantly reduced time spent in sedentary activities. However, improvements in physical activity and hypothesized mediators of physical activity behavior were not observed. Future studies are encouraged to explore alternative mechanisms of behavior change derived from integrated and socio-ecological theories.

The nutrition and enjoyable activity for teen girls study: a cluster randomized controlled trial.

BACKGROUND: Obesity prevention among youth of low SES is a public health priority given the higher prevalence of youth obesity in this population subgroup. PURPOSE: To evaluate the 24-month impact of a school-based obesity prevention program among adolescent girls living in low-income communities. DESIGN: The study was a school-based group RCT, the Nutrition and Enjoyable Activity for Teen Girls (NEAT Girls) intervention. SETTING/PARTICIPANTS: The study involved 12 secondary schools located in low-income communities in New South Wales, Australia. Participants were 357 adolescent girls (aged 13.2 ± 0.5 years). INTERVENTION: The 12-month multicomponent intervention was guided by social cognitive theory and involved strategies to promote physical activity, reduce sedentary behaviors, and improve dietary outcomes. MAIN OUTCOME MEASURES: The primary outcome was BMI, and secondary outcomes were BMI z-score; percentage body fat (bioelectrical impedance analysis); physical activity (accelerometers); dietary intake; and recreational screen-time (self-report). Data were collected in 2010-2012 and analyzed in 2012. RESULTS: After 24 months, there were no intervention effects on BMI (adjusted mean difference -0.33, 95% CI= -0.97, 0.28, p=0.353) and BMI z-score (-0.12, 95% CI= -0.27, 0.04, p=0.178). However, there was a group-by-time interaction for percentage body fat (-1.96%, 95% CI= -3.02, -0.89, p=0.006). Intervention effects for physical activity, screen time, and dietary intake were not significant. CONCLUSIONS: The NEAT Girls intervention did not result in effects on the primary outcome. Further study of youth who are "at risk" of obesity should focus on strategies to improve retention and adherence in prevention programs. TRIAL REGISTRATION: This study is registered at Australian New Zealand Clinical Trials ACTRN1261000033004.

Hyperglycemia accelerates apparent diffusion coefficient-defined lesion growth after focal cerebral ischemia in rats with and without features of metabolic syndrome.

Poststroke hyperglycemia is associated with a poor outcome yet clinical management is inadequately informed. We sought to determine whether clinically relevant levels of hyperglycemia exert detrimental effects on the early evolution of focal ischemic brain damage, as determined by magnetic resonance imaging, in normal rats and in those modeling the 'metabolic syndrome'. Wistar Kyoto (WKY) or fructose-fed spontaneously hypertensive stroke-prone (ffSHRSP) rats were randomly allocated to groups for glucose or vehicle administration before permanent middle cerebral artery occlusion. Diffusion-weighted imaging was carried out over the first 4 hours after middle cerebral artery occlusion and lesion volume calculated from apparent diffusion coefficient maps. Infarct volume and immunostaining for markers of oxidative stress were measured in the fixed brain sections at 24 hours. Hyperglycemia rapidly exacerbated early ischemic damage in both WKY and ffSHRSP rats but increased infarct volume only in WKY rats. There was only limited evidence of oxidative stress in hyperglycemic animals. Acute hyperglycemia, at clinically relevant levels, exacerbates early ischemic damage in both normal and metabolic syndrome rats. Management of hyperglycemia may have greatest benefit when performed in the acute phase after stroke in the absence or presence of comorbidities.

Testing social-cognitive theory to explain physical activity change in adolescent girls from low-income communities.

PURPOSE: The aim of this study was to test the hypothesized structural paths in Bandura's social-cognitive theory (SCT) model on adolescent girls' physical activity following a 12-month physical activity and dietary intervention to prevent obesity. METHOD: We conducted a 12-month follow-up study of 235 adolescent girls (M(age) = 13.2 years, SD = 0.4) from 12 secondary schools located in low-income communities. At baseline, participants completed SCT scales related to physical activity (i.e., self-efficacy, intention, parental support, and outcome expectations). At baseline and 12-month follow-up (postintervention), participants wore accelerometers for 7 days. Structural equation modeling was used to determine if Time 1 measures predicted physical activity at 12-month follow-up after adjusting for baseline activity. RESULTS: The model explained 28% and 34% of the variance in physical activity and intention, respectively. Model fit indexes indicated the data were a good fit to the model; however, only self-efficacy was associated with physical activity at 12 months. There was no support for intention or outcome expectations as proximal determinants of behavior. Self-efficacy was associated with outcome expectations and parental support; however, only outcome expectations predicted intention. CONCLUSIONS: Current findings indicate a large proportion of the variance for physical activity and intention remains unexplained and that the proposed pathways in the SCT model were not fully supported. Future model testing may need to consider augmentation or integration of theoretical models, which may include ecological components if we are to advance our understanding of physical activity behavior in this subgroup of the adolescent population.