Vammaiset lapset keskiajalla

Kirjallisuusarvostelu

Evaluation of two experimental models of hepatic encephalopathy in rats

The serious neuropsychological repercussions of hepatic encephalopathy have led to the creation of several experimental models in order to better understand the pathogenesis of the disease. In the present investigation, two possible causes of hepatic encephalopathy, cholestasis and portal hypertension, were chosen to study the behavioral impairments caused by the disease using an object recognition task. This working memory test is based on a paradigm of spontaneous delayed non-matching to sample and was performed 60 days after surgery. Male Wistar rats (225-250 g) were divided into three groups: two experimental groups, microsurgical cholestasis (N = 20) and extrahepatic portal hypertension (N = 20), and a control group (N = 20). A mild alteration of the recognition memory occurred in rats with cholestasis compared to control rats and portal hypertensive rats. The latter group showed the poorest performance on the basis of the behavioral indexes tested. In particular, only the control group spent significantly more time exploring novel objects compared to familiar ones (P < 0.001). In addition, the portal hypertension group spent the shortest time exploring both the novel and familiar objects (P < 0.001). These results suggest that the existence of portosystemic collateral circulation per se may be responsible for subclinical encephalopathy.

Changes in tau phosphorylation levels in the hippocampus and frontal cortex following chronic stress

Studies have indicated that early-life or early-onset depression is associated with a 2- to 4-fold increased risk of developing Alzheimers disease (AD). In AD, aggregation of an abnormally phosphorylated form of the tau protein may be a key pathological event. Tau is known to play a major role in promoting microtubule assembly and stabilization, and in maintaining the normal morphology of neurons. Several studies have reported that stress may induce tau phosphorylation. The main aim of the present study was to investigate possible alterations in the tau protein in the hippocampus and frontal cortex of 32 male Sprague-Dawley rats exposed to chronic unpredictable mild stress (CUMS) and then re-exposed to CUMS to mimic depression and the recurrence of depression, respectively, in humans. We evaluated the effects of CUMS, fluoxetine, and CUMS re-exposure on tau and phospho-tau. Our results showed that a single exposure to CUMS caused a significant reduction in sucrose preference, indicating a state of anhedonia. The change in behavior was accompanied by specific alterations in phospho-tau protein levels, but fluoxetine treatment reversed the CUMS-induced impairments. Moreover, changes in sucrose preference and phospho-tau were more pronounced in rats re-exposed to CUMS than in those subjected to a single exposure. Our results suggest that changes in tau phosphorylation may contribute to the link between depression and AD.

IFRS 9 – standardiuudistus Big Four -tilintarkastusyhteisöjen näkökulmasta – kommenttikirjeiden empiirinen analyysi

Since 2008, One of the International Accounting Standards Board’s (IASB) objective has been to replace the old IAS 39 – Financial Instruments standard. IASB achieved this objective in July 2014 when they published the new IFRS 9 – Financial Instruments after many phases. In this study, the main purpose was to find out how the Big Four – audit entities have welcomed the different reforms which IFRS 9 brings to the treatment of financial instruments in the financial statements. Alongside with this, the study presents a short overview to the common attitude towards the new standard. The study proceeds so that the most siginificant reforms have been divided into three main categories and inside of these more precisely to single reforms. This study is based on the qualitative research method. The empirical data of the study consists of comment letters by the Big Four – entities, which have been sent to the IASB regarding Exposure Drafts (ED) of IFRS 9. In total IASB received 757 comment letters regarding to the specific EDs. In this study the population were restricted to 16 comment letters sent by the Big Four – entities. The data is available at IFRS Foundation’s website. According to the research results Big Four – entities think that the reforms which IFRS 9 brings are mainly welcome. In its entirety Big Four – entities consider IFRS 9 better than its predecessor IAS 39. There were differnces in opinions towards IFRS 9 and specific reforms among the Big Four - entities. According to the findings the best reforms were related to the efficiency demands of hedge accounting and to impairments and the valuation of credit losses. The least popular reforms were the reforms regarding the measurement of financial assets and liabilities; more specifically fair value option and the reforms concerning equity instruments were viewed as most challenging.

Natural born weight gainers: The mechanisms of obesity in transgenic mice overexpressing neuropeptide Y

Neuropeptide Y (NPY) is a neurotransmitter promoting energy storage by activating Y-receptors and thus affecting food intake, thermogenesis and adipose tissue metabolism. NPY is expressed both in the central and sympathetic nervous system. Hypothalamic NPY is known to stimulate feeding, but the effects of noradrenergic neuron NPY are more ambiguous. Chronic stress stimulates fat accumulation via NPY release from noradrenergic neurons. Furthermore, polymorphism in the human Npy gene has been associated with metabolic disturbances and increased NPY secretion after sympathetic stimulation. The main objective of this study was to clarify the mechanisms of noradrenergic neuron NPY in the development of obesity. The metabolic phenotype of a homozygous mouse overexpressing NPY in the brain noradrenergic neurons and sympathetic nervous system (OE-NPYDβH mouse) was characterized. OE-NPYDβH mice had an increased fat mass and body weight, which caused impairments of glucose metabolism and hyperinsulinaemia with age. There were no differences in energy intake or expenditure, but the sympathetic tone was down-regulated and the endocannabinoid system activated. Furthermore, peripheral Y2-receptors in energy-rich conditions played an important role in mediating the fat-accumulating effect of NPY. These results indicate that noradrenergic neuron NPY promotes obesity via direct effects in the periphery and by modulating the sympatho-adrenal and endocannabinoid systems. Additionally, NPY in the central noradrenergic neurons is believed to possess many important roles. The phenotype of the OE-NPYDβH mouse resembles the situations of chronic stress and Npy gene polymorphism and thus these mice may be exploited in testing novel drug candidates for the treatment of obesity.

Electrophysiological and behavioural correlates of facial identity and expression perception deficits following a closed head injury /

A large variety of social signals, such as facial expression and body language, are conveyed in everyday interactions and an accurate perception and interpretation of these social cues is necessary in order for reciprocal social interactions to take place successfully and efficiently. The present study was conducted to determine whether impairments in social functioning that are commonly observed following a closed head injury, could at least be partially attributable to disruption in the ability to appreciate social cues. More specifically, an attempt was made to determine whether face processing deficits following a closed head injury (CHI) coincide with changes in electrophysiological responsivity to the presentation of facial stimuli. A number of event-related potentials (ERPs) that have been linked specifically to various aspects of visual processing were examined. These included the N170, an index of structural encoding ability, the N400, an index of the ability to detect differences in serially presented stimuli, and the Late Positivity (LP), an index of the sensitivity to affective content in visually-presented stimuli. Electrophysiological responses were recorded while participants with and without a closed head injury were presented with pairs of faces delivered in a rapid sequence and asked to compare them on the basis of whether they matched with respect to identity or emotion. Other behavioural measures of identity and emotion recognition were also employed, along with a small battery of standard neuropsychological tests used to determine general levels of cognitive impairment. Participants in the CHI group were impaired in a number of cognitive domains that are commonly affected following a brain injury. These impairments included reduced efficiency in various aspects of encoding verbal information into memory, general slower rate of information processing, decreased sensitivity to smell, and greater difficulty in the regulation of emotion and a limited awareness of this impairment. Impairments in face and emotion processing were clearly evident in the CHI group. However, despite these impairments in face processing, there were no significant differences between groups in the electrophysiological components examined. The only exception was a trend indicating delayed N170 peak latencies in the CHI group (p = .09), which may reflect inefficient structural encoding processes. In addition, group differences were noted in the region of the N100, thought to reflect very early selective attention. It is possible, then, that facial expression and identity processing deficits following CHI are secondary to (or exacerbated by) an underlying disruption of very early attentional processes. Alternately the difficulty may arise in the later cognitive stages involved in the interpretation of the relevant visual information. However, the present data do not allow these alternatives to be distinguished. Nonetheless, it was clearly evident that individuals with CHI are more likely than controls to make face processing errors, particularly for the more difficult to discriminate negative emotions. Those working with individuals who have sustained a head injury should be alerted to this potential source of social monitoring difficulties which is often observed as part of the sequelae following a CHI.

An assessment of autism knowledge in the medical field

Once thought to be rare, pervasive developmental disorders (PDDs) are now recognized as the most common neurological disorders affecting children and one of the most common developmental disabilities (DD) in Canada (Autism Society of Canada, 2006). Recent reports indicate that PDDs currently affect 1 in 150 children (Centre for Disease Control and Prevention, 2007). The purpose of this research was to provide an understanding of medical resident and practicing physicians' basic knowledge regarding PDDs. With a population of children with PDDs who present with varying symptoms, the ability for medical professionals to provide general information, diagnosis, appropriate referrals, and medical care can be quite complex. A basic knowledge of the disorder is only a first step in providing adequate medical care to individuals with autism and their families. An updated version of Stone's (1987) Autism survey was administered to medical residents at four medical schools in Canada and currently practicing physicians at three medical schools and one community health network. As well, a group of professionals specializing in the field ofPDDs, participating in research and clinical practice, were surveyed as an 'expert' group to act as a control measure. Expert responses were consistent with current research in the field. General findings indicated few differences in overall knowledge between residents and physicians, with misconceptions evident in areas such as the nature of the disorder, qualitative characteristics of autism, and effective interventions. Results were also examined by specialty and, while pediatricians demonstrated additional accurate 11 knowledge regarding the nature of the disorder and select qualitative impairments, both residents and practicing physicians demonstrated misconceptions about PDDs. This preliminary study replicated the findings of Stone (1987) and Heidgerken (2005) concerning several misconceptions of PDDs held by residents and practicing physicians. Future research should focus on additional replications with validated measures as well as the gathering of qualitative information, in order to inform the medical profession of the need for education in PDDs at training and professional levels.

The role of physical activity and perceived adequacy on cardiorespiratory fitness in children with developmental coordination disorder

Evidence suggests that children with developmental coordination disorder (DCD) have lower levels of cardiorespiratory fitness (CRF) compared to children without the condition. However, these studies were restricted to field-based methods in order to predict V02 peak in the determination of CRF. Such field tests have been criticised for their ability to provide a valid prediction of V02 peak and vulnerability to psychological aspects in children with DCD, such as low perceived adequacy toward physical activity. Moreover, the contribution of physical activity to the variance in V02 peak between the two groups is unknown. The purpose of our study was to determine the mediating role of physical activity and perceived adequacy towards physical activity on V02 peak in children with significant motor impairments. This prospective case-control design involved 122 (age 12-13 years) children with significant motor impairments (n=61) and healthy matched controls (n=61) based on age, gender and school location. Participants had been previously assessed for motor proficiency and classified as a probable DCD (p-DCD) or healthy control using the movement ABC test. V02 peak was measured by a progressive exercise test on a cycle ergometer. Perceived adequacy was measured using a 7 -item subscale from Children's Selfperception of Adequacy and Predilection for Physical Activity scale. Physical activity was monitored for seven days with the Actical® accelerometer. Children with p-DCD had significantly lower V02 peak (48.76±7.2 ml/ffm/min; p:50.05) compared to controls (53.12±8.2 ml/ffm/min), even after correcting for fat free mass. Regression analysis demonstrated that perceived adequacy and physical activity were significant mediators in the relationship between p-DCD and V02 peak. In conclusion, using a stringent laboratory assessment, the results of the current study verify the findings of earlier studies, adding low CRF to the list of health consequences associated with DCD. It seems that when testing for CRF in this population, there is a need to consider the psychological barriers associated with their condition. Moreover, strategies to increase physical activity in children with DCD may result in improvement in their CRF.

Using fuction-based CBT with parent involvement to treat OCD in two school-age children with high-functioning autism

Obsessive Compulsive Disorder (OCD) involves excessive worry coupled with engaging in rituals that are believed to help alleviate the worry. Pervasive Developmental Disorders (PODs) are characterized by impairments in social interaction, communication, and the presence of repetitive and/or restrictive behaviours (American Psychiatric Association, 2000). Research suggests that as many as 81% of children with a POD also meet criteria for a diagnosis ofOCD. Currently, only a handful of studies have investigated the use of Cognitive Behavioural Therapy (CBT) in treating OCD in children with autism (Reaven & Hepburn, 2003 ; Sze & Wood, 2007; Lehmkuhl, Storch, Bodtish & Geflken, 2008). In these case studies. the use of a multi-modal CBT treatment package was successful in alleviating OCD behaviours. The current study used function-based CBT with parent involvement and behavioural supplements to treat 2 children with POD and OCD. Using a multiple baseline design across behaviours and participants, parents reported that their child 's anxiety was alleviated and these gains were maintained at 6-month follow-up. According to results of the Children 's Yale-Brown Obsessive Compulsive Scale (Goodman, Price, Rasmussen, Riddle, & Rapoport, 1986) from preto post-test, OCD behaviours of the children decreased II"om the severe to the mild range. In addition, the parents rated the family's level of interference related to their child 's OCD as substantially lower. Last, the CBT treatment received high ratings of consumer satisfaction.

The effects of upper extremity functional electrically stimulated (FES) exercise training on upper limb function in individuals with tetraplegia

Functional Electrically Stimulated (FES) ami cycle ergometry is a relatively new technique for exercise in individuals with impairments of the upper limbs. The purpose of this study was to determine the effects of 12 weeks of FES arm cycle ergometry on upper limb function and cardiovascular fitness in individuals with tetraplegia. F!ve subjects (4M/1F; mean age 43.8 ± 15.4 years) with a spinal cord injury of the cervical spine (C3- C7; ASIA B-D) participated in 12 weeks of3 times per week FES arm cycle ergometry training. Exercise performance measures (time to fatigue, distance to fatigue, work rate) were taken at baseline, 6 weeks, and following 12 weeks of training. Cardiovascular measures (MAP, resting HR, average and peak HR during exercise, cardiovascular efficiency) and self reported upper limb function (as determined by the CUE, sf-QIF, SCI-SET questionnaires) were taken at baseline and following 12 weeks of training. Increases were found in time to fatigue (84.4%), distance to fatigue (111.7%), and work rate (51.3%). These changes were non-significant. There was a significant decrease in MAP (91.1 ± 13.9 vs. 87.7 ± 14.7 mmHg) following 12 weeks ofFES arm cycle ergometry. There was no significant change in resting HR or average and peak HR during exercise. Cardiovascular efficiency showed an increase following the 12 weeks ofFES training (142.9%), which was non-significant. There were no significant changes in the measures of upper limb function and spasticity. Overall, FES arm cycle ergometry is an effective method of cardiovascular exercise for individuals with tetraplegia, as evidenced by a significant decrease in MAP, however it is unclear whether 12 weeks of thrice weekly FES arm cycle ergometry may effectively improve upper limb function in all individuals with a cervical SCI.

Closing the summer learning gap for vulnerable junior kindergarten students

Under current academic calendars across North America, summer vacation creates a significant gap in the learning cycle. I t has been argued that this gap actually decreases student achievement levels over the course of the summer. In a synthesis of 39 studies Cooper, Nye, Charlton, Lindsay, & Greathouse (1996) indicated that summer learning loss equaled at least one month of instruction as measured by grade level equivalents on standardized test scores whereby children's test scores were at least one month lower when they returned to school in the fall than scores were when students left in the summer. Specifically, Cooper et aI., (1996) found that the summer learning loss phenomena may be particularly troublesome for less advantaged children including those with speech and language delays, children at-risk for reading disabilities, children from lower socio-economic backgrounds, and children learning English as a second language. In general, research illustrated clearly that the summer learning gap can be particularly problematic for vulnerable children and furthermore, that literacy skills may be the area of achievement that is most affected. A foundational pillar to this research project is including primary caregivers as authentic partners in a summer literacy program designed to support their children's literacy needs. This pillar led the research team to use the Learning Begins at Home: A Research-Based Family Literacy Program Curriculum designed by Antoinette Doyle, Kathleen Hipfner-Boucher, and Janette Pelletier from the Ontario Institute for the Studies of Education. The LBH program is designed to be flexibly adapted to suit the needs of each individual participating family. As indicated by Timmons (2008) literacy interventions are most powerful when they include authentic family involvement. Based on this research, a requirement for participating in the summer literacy program was involvement of a child and one of their primary caregivers. The participating caregiver was integrally involved in the program, participating in workshop activities prior to and following hands-on literacy work with their child. By including primary caregivers as authentic partners, the research team encouraged a paradigmatic shift in the family whereby literacy activities become routine within their household. 5 Participants in this study were 14 children from junior kindergarten classrooms within the Niagara Catholic District School Board. As children were referred to the program, they were assessed by a trained emergent literacy specialist (from Speech Services Niagara) to identify whether they met the eligibility requirements for participation in the summer program. To be eligible to participate, children demonstrated significant literacy needs (i.e. below 25%ile on the Test of Preschool Early Literacy described below). Children with low incidence disabilities (i.e. profound sensory impairments, severe intellectual impairments, developmental disabilities, etc) were excluded as participants. The research team used a standard pre- and posttest design whereby all participating children were assessed with the Test of Preschool Early Literacy (Lonigan et aI., 2007), and a standard measure of letter names and sounds. Pretests were administered two weeks prior to the commencement of the program and the first set of posttests was administered immediately following the program. A second set of posttests was administered in December 2009 to measure the sustainability of the program. As a result of the program, all children scored statistically significantly higher on their literacy scores at the post-program assessment point immediately following the program and also at the Dec-post-program assessment point. These results in general indicated that the summer family literacy program made an immediate impact on the emergent literacy skills of participating children. All participating children demonstrated significant increases in print and phonological awareness as well as their letter sound understanding.

Sleep and information processing in individuals who have sustained a traumatic brain injury

Individuals who have sustained a traumatic brain injury (TBI) often complain of t roubl e sleeping and daytime fatigue but little is known about the neurophysiological underpinnings of the s e sleep difficulties. The fragile sleep of thos e with a TBI was predicted to be characterized by impairments in gating, hyperarousal and a breakdown in sleep homeostatic mechanisms. To test these hypotheses, 20 individuals with a TBI (18- 64 years old, 10 men) and 20 age-matched controls (18-61 years old, 9 men) took part in a comprehensive investigation of their sleep. While TBI participants were not recruited based on sleep complaint, the fmal sample was comprised of individuals with a variety of sleep complaints, across a range of injury severities. Rigorous screening procedures were used to reduce potential confounds (e.g., medication). Sleep and waking data were recorded with a 20-channel montage on three consecutive nights. Results showed dysregulation in sleep/wake mechanisms. The sleep of individuals with a TBI was less efficient than that of controls, as measured by sleep architecture variables. There was a clear breakdown in both spontaneous and evoked K-complexes in those with a TBI. Greater injury severities were associated with reductions in spindle density, though sleep spindles in slow wave sleep were longer for individuals with TBI than controls. Quantitative EEG revealed an impairment in sleep homeostatic mechanisms during sleep in the TBI group. As well, results showed the presence of hyper arousal based on quantitative EEG during sleep. In wakefulness, quantitative EEG showed a clear dissociation in arousal level between TBls with complaints of insomnia and TBls with daytime fatigue. In addition, ERPs indicated that the experience of hyper arousal in persons with a TBI was supported by neural evidence, particularly in wakefulness and Stage 2 sleep, and especially for those with insomnia symptoms. ERPs during sleep suggested that individuals with a TBI experienced impairments in information processing and sensory gating. Whereas neuropsychological testing and subjective data confirmed predicted deficits in the waking function of those with a TBI, particularly for those with more severe injuries, there were few group differences on laboratory computer-based tasks. Finally, the use of correlation analyses confirmed distinct sleep-wake relationships for each group. In sum, the mechanisms contributing to sleep disruption in TBI are particular to this condition, and unique neurobiological mechanisms predict the experience of insomnia versus daytime fatigue following a TBI. An understanding of how sleep becomes disrupted after a TBI is important to directing future research and neurorehabilitation.

Frontal Lobe Function and Performance Monitoring following Total Sleep Deprivation

Imaging studies have shown reduced frontal lobe resources following total sleep deprivation (TSD). The anterior cingulate cortex (ACC) in the frontal region plays a role in performance monitoring and cognitive control; both error detection and response inhibition are impaired following sleep loss. Event-related potentials (ERPs) are an electrophysiological tool used to index the brain's response to stimuli and information processing. In the Flanker task, the error-related negativity (ERN) and error positivity (Pe) ERPs are elicited after erroneous button presses. In a Go/NoGo task, NoGo-N2 and NoGo-P3 ERPs are elicited during high conflict stimulus processing. Research investigating the impact of sleep loss on ERPs during performance monitoring is equivocal, possibly due to task differences, sample size differences and varying degrees of sleep loss. Based on the effects of sleep loss on frontal function and prior research, it was expected that the sleep deprivation group would have lower accuracy, slower reaction time and impaired remediation on performance monitoring tasks, along with attenuated and delayed stimulus- and response-locked ERPs. In the current study, 49 young adults (24 male) were screened to be healthy good sleepers and then randomly assigned to a sleep deprived (n = 24) or rested control (n = 25) group. Participants slept in the laboratory on a baseline night, followed by a second night of sleep or wake. Flanker and Go/NoGo tasks were administered in a battery at 1O:30am (i.e., 27 hours awake for the sleep deprivation group) to measure performance monitoring. On the Flanker task, the sleep deprivation group was significantly slower than controls (p's <.05), but groups did not differ on accuracy. No group differences were observed in post-error slowing, but a trend was observed for less remedial accuracy in the sleep deprived group compared to controls (p = .09), suggesting impairment in the ability to take remedial action following TSD. Delayed P300s were observed in the sleep deprived group on congruent and incongruent Flanker trials combined (p = .001). On the Go/NoGo task, the hit rate (i.e., Go accuracy) was significantly lower in the sleep deprived group compared to controls (p <.001), but no differences were found on false alarm rates (i.e., NoGo Accuracy). For the sleep deprived group, the Go-P3 was significantly smaller (p = .045) and there was a trend for a smaller NoGo-N2 compared to controls (p = .08). The ERN amplitude was reduced in the TSD group compared to controls in both the Flanker and Go/NoGo tasks. Error rate was significantly correlated with the amplitude of response-locked ERNs in control (r = -.55, p=.005) and sleep deprived groups (r = -.46, p = .021); error rate was also correlated with Pe amplitude in controls (r = .46, p=.022) and a trend was found in the sleep deprived participants (r = .39, p =. 052). An exploratory analysis showed significantly larger Pe mean amplitudes (p = .025) in the sleep deprived group compared to controls for participants who made more than 40+ errors on the Flanker task. Altered stimulus processing as indexed by delayed P3 latency during the Flanker task and smaller amplitude Go-P3s during the Go/NoGo task indicate impairment in stimulus evaluation and / or context updating during frontal lobe tasks. ERN and NoGoN2 reductions in the sleep deprived group confirm impairments in the monitoring system. These data add to a body of evidence showing that the frontal brain region is particularly vulnerable to sleep loss. Understanding the neural basis of these deficits in performance monitoring abilities is particularly important for our increasingly sleep deprived society and for safety and productivity in situations like driving and sustained operations.

Investigating the Biological Effects of Rosemary (Rosmarinus officinalis L.) Extract on Skeletal Muscle Glucose Uptake

Skeletal muscle (SKM) is the most important tissue in maintaining glucose homeostasis and impairments in this tissue leads to insulin resistance (IR). Activation of 5’ AMP-activated kinase (AMPK) is viewed as a targeted approach to counteract IR. Rosemary extract (RE) has been reported to decrease blood glucose levels but its effects on SKM are not known. We hypothesized that RE acts directly on SKM to increase glucose uptake (GU). We found an increase in GU (184±5.07% of control, p<0.001) in L6 myotubes by RE to levels similar to insulin and metformin. Carnosic acid (CA) and rosmarinic acid (RA), major polyphenols found in RE, increased GU. RE, CA, and RA significantly increased AMPK phosphorylation and their effects on GU was reduced by an AMPK inhibitor. Our study is the first to show a direct effect of RE, CA and RA on SKM GU by a mechanism that involves AMPK activation.

Intrahemispheric dysfunction in primary motor cortex without corpus callosum: a transcranial magnetic stimulation study

Affiliation: Département de Psychologie, Université de Montréal