Mechanisms of impaired functional recovery in diabetic mice following stroke

Diabetics are two to four times more likely than non-diabetics to suffer a stroke during their lifetime, and their prognosis for recovery from stroke is poor. Diabetes is known to negatively affect blood vessels throughout the body, including the eye, heart, kidney, and limbs, leading to a heightened risk of stroke in diabetics. Poor circulation and peripheral nerve damage can lead to blindness, hearing loss, foot injury and amputation. High blood pressure is common in diabetics and increases the risk of heart disease and stroke. However, little is known about how the vascular changes associated with diabetes affect the brain and contribute to poorer recovery of function following stroke.

Dr. Kelly Tennant's research will determine why diabetics suffer from greater impairments following strokes. She will monitor changes in neurons and blood vessels over time following a stroke in diabetic mice and assess the relationship between these changes and recovered use of the forelimb. Dr. Tennant will employ cutting edge in vivo imaging technologies such as intrinsic optical signal, two-photon, and voltage sensitive dye imaging, combined with behavioural testing of forelimb function.

These experiments will shed light on how neurons and blood vessels of diabetics respond differently to ischemic stroke and how these differences contribute to poor behavioural recovery in diabetic stroke survivors. This research will aid understanding of the greater impairment caused by stroke in diabetic patients and lead towards development of treatments that ameliorate the negative effects of diabetes on the brain.

Mitigation of hippocampal dysfunction and cognitive deficits in early-symptomatic YAC128 transgenic mice for Huntington’s disease

Huntington's disease is a devastating neurodegenerative disorder affecting between three and 10 individuals per 100,000 in the Western world. It is caused by a mutation in the huntingtin gene, which results in the accumulation of mutated huntingtin protein in the brain and the eventual degeneration of certain types of brain cells. The disease is primarily characterized by the onset of motor deficits; this develops when the striatum region deep within the brain begins to degenerate. However, Huntington’s disease patients commonly show cognitive impairments decades before the onset of the motor symptoms. The hippocampus is a brain region known to be involved both in cognitive (i.e. learning and memory) and emotional (i.e. depression) processes.

Dr. Joana Gil-Mohapel is investigating whether the hippocampus is involved in the early cognitive impairments in Huntington’s disease. She is working with a mouse model of Huntington’s disease, which closely mimics the human condition. These mice demonstrate profound structural and functional deficits in this region; significantly, as seen in Huntington’s disease patients, these deficits can be detected when the animals are still in an early-symptomatic stage, before the onset of motor symptoms. Therefore, the goal of the present research is to gain a better understanding of how this structure is affected in this mouse model.

Dr. Gil-Mohapel will investigate whether relevant cellular pathways are altered in this brain region and whether therapies aimed at promoting hippocampal function can reverse these deficits and be of therapeutic value for Huntington’s disease. She hopes her research will help elucidate novel targets for the mitigation of the cognitive deficits characteristic of early-stage Huntington’s disease patients.

Evaluation of the Residential Program Care Delivery Model

CDM was launched in Fraser Health in July 2010, with plans to implement the model across all residential care beds in the Health Authority. The model consists of three inter-related aspects: staff mix, funding methodology and direct care hours. CDM sets a goal of reaching 3.36 direct care hours per resident per day across Fraser Health by targeting residents, their families and staff in residential care programs in FH-operated facilities. The evaluation project will examine Phase 1 of the implementation of CDM (July 2010 to January 2011) and will include monitoring funding indicators as well as quality of care indicators.

Impacts of a Palliative Approach for Nursing (IPAN)

This practice-relevant nursing health services research initiative will address the questions:

  1. How and in which contexts can a palliative approach better meet the needs of patients with a life-limiting illness and their family members?
  2. How can a palliative approach guide the development of innovations in health care delivery systems to better support nursing practice and the health system in British Columbia?

Continue reading “Impacts of a Palliative Approach for Nursing (IPAN)”

Evaluation of the Integration of Nurse Practitioners into the BC Healthcare System

The nurse practitioner (NP) role is new to BC and its impact has yet to be evaluated. The proposed multi-year study will evaluate a practice innovation – the integration of NPs into the BC healthcare system, and will establish a framework for sustainable ongoing evaluation of the impact of NP practice on those they serve and the health care system. The study process will be divided into three parts addressing the following broad questions:

  1. What changes result for patients, and what are the implications for the health care system when NPs become part of the care process?
  2. What is the impact of adding a NP to the functioning of collaborative health care teams?
  3. What are the practice settings and scope of practice of NPs working in BC?

The final work of the project team will be to use the study findings to develop an ongoing evaluation method for future data collection and evaluation of NPs’ practice and impact.

Small molecules with affinity for S100A7, a tumorigenic protein in breast cancer

Biochemical events in humans are influenced and triggered by cell signalling pathways and their associated feedback loops. Changes and mutations to members of these signalling pathways can cause cancer to develop. Trouble can also occur when alternative pathways are triggered or when built-in negative feedback (“”shut off””), loops are not triggered. In the case of cancer, the observed uncontrolled cell growth results in tumours that can eventually metastasize and send diseased cells throughout the body resulting in an aggressive, invasive cancer. Before the aggressive stage of cancer is reached, the disease often goes through stages of progressively worsening cancers. In breast cancer, Ductal Carcinoma In Situ (DCIS), is one such stage prior to invasive disease. With DCIS, the cancer is contained to a duct and has not yet spread to other areas of the breast or body. Research at the BC Cancer Agency’s Deeley Research Centre has revealed two proteins, S100A7 and Jab1, involved in a pathway associated with the transition from DCIS to invasive breast cancer. There is compelling evidence to suggest that if the interaction between S100A7 and Jab1 were prevented or disrupted, the critical signalling pathways would not be triggered and the progress of invasive breast cancer would be stopped. Amanda Whiting is researching the effects of blocking the interactions between S100A7 and Jab1 by using small, drug-like molecules. In particular, Ms. Whiting’s research uses the molecule 2,6-ANS, as the basis for modifications to improve binding to S100A7 and decrease binding to other important body proteins. Her research will provide an expanded understanding of small molecule binding requirements and, in turn, allow for appropriate modifications to the compounds. Moreover, her work explores a potential new target for breast cancer therapy using small molecule inhibitors to disrupt a cancer-associated protein-protein interaction.

Evaluation of Neurogenesis and Synaptic Plasticity in the YAC128 Transgenic Mouse Model of Huntington's Disease

Currently, there are no therapeutic options available to help regenerate lost brain tissue in patients with Huntington’s disease (HD). However, a large body of evidence suggests that the adult brain retains a limited ability to generate new neurons (a process called neurogenesis), and that adult neuronal stem cells that underlie this process may be a possible endogenous source of healthy neurons for the treatment of certain neurodegenerative diseases including HD. Significant strides are being made in understanding how neural stem cells could be used in regenerative transplant therapies in a number of pathologies. However, whether a “”diseased”” brain has the capacity to sustain regenerative therapy remains unclear. Jessica Simpson is studying how HD affects two populations of endogenously active neuronal stem cells. These stem cells normally give rise to new neurons through out life, so they offer an endogenous indicator of how HD is affecting the brains capacity to regenerate. In addition, she will be testing whether non-invasive therapies aimed at restoring adult neurogenesis and synaptic plasticity (i.e. voluntary physical exercise), might be beneficial in reversing some of the cognitive as well as neuropathological and motor deficits seen in HD mouse models. Adult neurogenesis and synaptic plasticity are thought to be involved in cognitive function, namely learning and memory, in the normal adult brain. Her studies will improve our existing knowledge of how adult neurogenesis and synaptic plasticity are affected in the HD brain and thereby improve our knowledge of the pathogenic mechanisms triggered by HD at the neuronal level. Ms. Simpson’s research may lead to the development of restorative therapeutic strategies that recruit endogenous stem cells into degenerated areas of the brain. Such strategies might also be useful for the treatment of other neurodegenerative diseases characterized by the loss of specific neuronal populations such as Parkinson’s disease. Moreover, the results from this study could potentially contribute to the growing body of evidence suggesting that the use of non-invasive therapeutic strategies, such as voluntary physical exercise and environmental enrichment, provide benefit in the treatment of neurodegenerative conditions such as Alzheimer’s disease.

A structure-function analysis of the exo-beta-D-N-acetylglucosaminidase StrH, an important Streptococcus pneumoniae virulence factor.

Streptococcus pneumoniae is a common bacterium that can cause serious infections like acute respiratory disease (pneumonia), infections of the brain and central nervous system (meningitis), blood infections (septicaemia, sometimes leading to sepsis), and ear infections (otitis media). This organism is one of the leading causes of death from infectious disease across the globe. In addition to showing a lethal synergism with the influenza virus, many strains of S. pneumoniae are rapidly becoming resistant to antibiotics and some strains have even been dubbed “”superbugs. From the practical perspective of combating S. pneumonia, there is a clear need to better understand how it makes us sick. Numerous studies have revealed that the ability of this germ to cause disease strongly depends on it attacking the sugars present in its host’s tissues. Dr. Pluvinage’s work focuses on one protein that performs this type of function, a large enzyme called StrH, which is necessary for S. pneumoniae to infect its most commonly targeted human organs, the lungs and the ears. StrH is responsible for removing an abundant sugar (N-acetylglucosamine) from the surface of host cells and the protective sugar layers found in mucus. Though the activity of StrH is known, precisely how it performs its job is not. Consequently, Dr. Pluvinage is working to characterize the protein’s complex, three-dimensional structure in order to better understand the protein’s function. The results of this research will provide a foundation for generating new small molecular inhibitors that might allow for the effective treatment of infections caused by S. pneumoniae “superbugs”.

Neural Mechanisms of Reward Learning and Cognitive Control in Children with Attention Deficit Hyperactivity Disorder

Attention Deficit Hyperactivity Disorder (ADHD), is characterized by its behavioural manifestations including difficulties with attention, hyperactivity and impulsivity. It is one of the most common childhood disorders with a prevalence rate of three to seven percent of school-aged children. ADHD carries a significant impact not only on children diagnosed with this disorder, but also on their families, schools, communities and the health care system. Numerous theories of ADHD have focused on deficits in executive functions, specifically cognitive control and the inability to inhibit inappropriate behaviours. Neuropsychological and neuroimaging studies in children with ADHD support a theory of frontal-subcortical dysfunction: specifically, a dysfunction in the midbrain dopamine (DA) system that may result in an impaired midbrain DA system and reinforcement learning, or the ability to learn to modify behaviour on the basis of rewarding and punishing stimuli in the environment. Furthermore, recent developments in reinforcement learning theory indicate that the midbrain DA system carries Reward Prediction Error (RPE) signals. Carmen Lukie is investigating how a midbrain DA system for reinforcement learning may be impaired in children with ADHD. This study follows on from her earlier research which showed that children with ADHD are particularly sensitive to the saliency of rewards. Specifically, she found that RPE signals in children with ADHD are modulated by the context in which feedback is given, and differs from what is observed in typically developing children. The current study will replicate this finding, while correcting for the limitations of the earlier study. Ultimately, the results of this research could lead to the development of novel, more effective behavioural and pharmacological treatments. Further, the research may expand to include individuals with substance abuse, pathological gambling, conduct and borderline personality disorders.

Towards a better understanding of adolescent depression: the roles of relational victimization and emotional support

The onset of depression in many individuals can be traced back to adolescence. Up to one-third of 12- to 16-year-olds report “feeling depressed,” and clinical depression among adolescents is associated with numerous adverse consequences, including increased risk for recurrent depression, suicide, hospitalization and general maladjustment. Adolescent depression has been identified as a chronic, continuous disorder that is in need of increased research attention. The prevalence of depression increases dramatically as children transition into adolescence. This is also consistent with increases in relational aggression, such as gossiping, name calling, and social exclusion. Interestingly, striking gender differences in the rates of depression also emerge at this time: adolescent girls’ rates increase more rapidly than boys’ rates of depression, and depression remains more prevalent in women than men. Researchers have suggested that interpersonal orientation is one of the most consistent psychological differences between males and females, and that females may be more psychologically vulnerable to peer victimization because they view their strong emotional attachments with others as central to their self-concept. At the same time, however, aspects of interpersonal relationships may serve to protect girls’ emotional reactions to relational aggression. Tracy Desjardins is examining the effects of peer and parental emotional support on adolescents’ emotional reactions to peer victimization, investigating whether they may be contributors to gender differences in emotional maladjustment. Her primary goal is to help dismantle the precise mechanisms by which certain interpersonal risk factors interact to produce depression at differential rates in males and females. Desjardins’ findings will contribute to increased knowledge about the origins of adolescent depression. Ultimately, this work could lead to more targeted treatment interventions and prevention strategies that consider differential gender processes.