Thesis (Master's Degree (Medical Technology)-- Cape Technikon, Cape Town, 1997 / There is, at present, no recognised diagnostic biochemical marker of Alzheimer's Disease (AD). Recently, Gunnerson and Haley, (1992), reported that the presence of glutamine synthetase (GS) in cerebrospinal fluid (CSF) samples showed a 97% correlation with patients diagnosed as having AD. GS was detected by photolabelling with [y32P]2-azido-ATP or [y32P]8azido- ATP and visualisation following sodium dodecyl sulphate polyacrylamide gel electrophoresis (SOS-PAGE) and autoradiography. This study set out to reproduce Gunnerson and Haley's methodology for labelling sheep GS in CSF using [y32P]8-azidoATP, to develop this assay or possibly another, using a fluorescent probe of ATP binding sites, into a robust procedure suitable for a routine diagnostic laboratory, and finally to assess whether the presence of GS in CSF is indeed a marker of AD.

Indiana University-Purdue University Indianapolis (IUPUI) / Hydrocephalus is a disease characterized by an increase in cerebrospinal fluid (CSF) in the ventricles of the brain. This manifests as a result of either overproduction or underabsorption of CSF leading to increases in pressure, swelling and loss of brain matter. Current treatments for this disease include surgical interventions via the introduction of shunts or endoscopic third ventriculostomy, both of which aim to redirect flow of CSF in to another cavity for absorption. Limited pharmacotherapies are available in the treatment of hydrocephalus, and there exists a clinical need for drug therapies, which can ameliorate the pathophysiology associated with hydrocephalus and ventriculomegaly. CSF is produced primarily by the choroid plexus (CP), found in the ventricles of the brain. Composed of a high resistance epithelium surrounding a capillary network, the CP epithelium acts as a barrier, regulating ion transport between the CSF and blood. Transient Receptor Potential Vanilloid-4 (TRPV4) is a nonselective Ca2+-permeable cation channel expressed in the CP which is being investigated for its role in CSF production. To study hydrocephalus, we utilize two model systems; the TMEM67-/- Wpk rat, and the PCP-R cell line. The Wpk rat model is used to study the effects of drug intervention on the development and progression of hydrocephalus. The PCP-R cell line is utilized for studies which aim to understand the mechanisms by which CSF is produced. Using Ussing chamber electrophysiology, we are able to study the role of specific channels, transporters and modulators in driving epithelial ion flux across the CP. This research aims to establish a role for TRPV4 in production and regulation of CSF, and to interrogate a mechanism by which this ion transport occurs. The chapters that follow describe components of the pathway by which TRPV4 is activated and ion flux is stimulated.

No description available.

A variety of neurologic illnesses including peripheral and cranial neuropathies, central vestibular disease, seizures and coma have been associated with hypothyroidism in dogs. Repeated studies have shown that there is loss of blood brain barrier (BBB) integrity in these animals. Current research has also shown the development cerebrospinal fluid abnormalities in neurologically normal hypothyroid dogs; a finding that is related to BBB degradation. This derangement may be secondary to atherosclerosis and vascular accidents. One possible mediator of vasospasm and ischemic brain injury is endothelin-1 (ET-1). Another group of mediators of vascular dysfunction that has been found in CSF of dogs with various other CNS diseases is matrix metalloproteinases (MMP). The purpose of this study was to assay molecular markers that may contribute to disruption in the blood brain barrier in chronically hypothyroid canines. We hypothesized that BBB disruption in hypothyroidism is mediated by ET-1 and MMPs, as evidenced by increased concentrations of these proteins in CSF compared to controls. Cerebrospinal fluid (CSF) previously collected from 9 control and 9 experimentally induced hypothyroid dogs was used. Administration of I-131 was used to create the experimental model. CSF from time points 0, 6, 12, and 18 months post-induction were evaluated using an ELISA kit for endothelin-1. CSF from each time point was also evaluated using gelatinase zymography to detect MMP-2,9, and 14. The endothelin assay was able to detect ET-1 in CSF as determined by a spike and recovery method. However, ET-1 was undetectable in CSF of control and hypothyroid dogs at all time points. Constitutively expressed MMP-2 was detectable in all dogs at all time points. No other MMPs were detectable in CSF. ET-1 and gelatinase MMP,-9, and -14 are not primary mediators of BBB damage in chronically hypothyroid dogs. They could be involved secondarily and may be better evaluated with different assays or in temporal association with the development of clinical signs of neurologic dysfunction. Additional research is needed to confirm this finding and to evaluate biomarkers of non-vascular components of the BBB. / Master of Science

No description available.

Delirium, or “acute confusion” is a common and serious acute neuropsychiatric syndrome mainly affecting older people. It is associated with multiple adverse outcomes, including an increased risk of developing dementia and increased mortality. The underlying mechanisms of delirium are poorly understood, and there are currently no specific treatments. This thesis investigated the roles of the hypothalamic-pituitary adrenal axis and inflammation in the pathophysiology of delirium, persistent delirium and cognitive decline following delirium. It investigated whether levels of cortisol in blood and cerebrospinal fluid (CSF) are elevated in delirium, with elevated pro-inflammatory and reduced anti-inflammatory cytokines. It also investigated whether there is loss of cortisol diurnal rhythm (in saliva) with elevated afternoon cortisol levels. The thesis investigated whether any hypercortisolaemia was sustained during the year after delirium, and whether this was associated with deterioration in cognition during the year after hip fracture. Finally, it also tested whether there are high levels of a marker of central nervous system damage (S100B) and of a dementia marker (tau) in CSF in delirium. A prospective observational cohort study was conducted in N=108 patients aged over 60 who had sustained a hip fracture, in whom 40% developed delirium. Participants gave informed consent or if they lacked capacity to give informed consent, this was given by their next of kin. Participants were assessed regularly for delirium, according to DSM IV criteria, during the two weeks after hip fracture. A sample of CSF was collected during the spinal anaesthetic performed for the operation to repair their fracture. Samples of blood and saliva were collected during the two weeks after the hip fracture operation. Participants were visited three, six and twelve months after their hip fracture for further delirium assessment, and a cognitive test battery was completed. Further samples of blood and saliva were collected at these visits. The study found evidence of high levels of cortisol and of S100B in CSF in those with active delirium, but there were no differences in levels of tau or cytokines in CSF. Those with delirium had elevated serum cortisol during the perioperative period, and elevated afternoon salivary cortisol, suggesting flattening of cortisol diurnal rhythm with failure to reach the normal diurnal nadir. After adjusting for confounders in a multivariate logistic regression analysis, serum cortisol was still predictive of delirium, but salivary cortisol AM:PM ratio had a trend towards significance. Those who had persistent delirium features in the months after hip fracture had significantly higher serum cortisol three months after hip fracture. There was a change in serum inflammatory profile in those with delirium, with a shift towards a pro-inflammatory state. Testing the study hypotheses surrounding cognition after delirium was very challenging, due to patient attrition and other factors. Some participants showed a trajectory of cognitive improvement, which was probably due to resolution of delirium during the year after hip fracture. Those with resolved delirium had deficits in verbal and visual memory. This study has improved understanding of the mechanisms of delirium, suggested further avenues for research and identified possible new therapeutic targets.

This dissertation is a critical examination of the relationship between sleep problems and/or disorders, particularly Obstructive Sleep Apnea (OSA) and Alzheimer Disease (AD). First, I conducted an exhaustive systematic review of existing literature, and identified gaps in research that led to specific research aims. For the first aim, I conducted the first ever-published meta-analysis examining sleep, cognitive decline and AD, providing an aggregate effect of sleep on AD. Second, focusing on OSA, I conducted a study examining OSA’s effect on longitudinal changes on AD biomarkers in cognitive normal, MCI and AD subjects, using data from the Alzheimer Disease Neuroimaging Initiative (ADNI). Lastly, I conducted a review, integrating over 3 decades of research examining OSA and cognition; OSA and subsequent cognitive decline; and OSA and AD; with particular focus in appreciating the heterogeneity of OSA and its outcomes in distinct age groups. Results and implications from my research indicate that ample evidence exists linking sleep impairments and circadian regulating mechanisms directly to clinical symptoms in AD. Sleep problems and/or disorders increases your risk of cognitive decline and AD. OSA is associated with increased AD biomarker burden over time, and effects longitudinal changes in these biomarkers, such that OSA subjects progress faster than non-OSA subjects do. OSA may be age-dependent in older adults (60 – 70 years old) and the elderly (70 years and above) and is associated with neurodegenerative diseases particularly, cognitive decline and AD. Intermittent hypoxia and sleep fragmentation are two main processes by which OSA induces neurodegenerative changes. Therefore, clinical interventions aimed at OSA, such as treatment with CPAP or dental appliances, in cognitive normal and MCI patients, could possibly slow the progression of cognitive impairment to AD.

Thesis (M.Dip.Tech.-Medical Tech)--Cape Technikon, 1997. / Bibliography: leaf. 59-62. Also available online.

Thesis (M.Tech.-Medical Technology)--Cape Technikon, 1997. / Bibliography: leaf 96-114. Also available online.

The design and construction of an electrochemical detector with two working electrodes located on the opposite walls of a thin-layer cell and its use as a detector for High Pressure Liquid Chromatography (HPLC) in the analysis of catecholamines in human cerebrospinal fluid are described. The location of the electrodes in this manner permits an electrochemically reversible or quasireversible couple to be electrolized more than once as it passes through the detector. If one electrode is held at a potential where oxidation takes place and the second electrode at a potential where reduction of this oxidized form back to the starting material occurs, then the current produced increases proportionately to the number of conversions that take place. A comparison of this cell in the dual-working-electrode and single-working-electrode mode shows an improvement in the signal-to-noise ratio by a factor of six. This HPLC system with electrochemical detection has been used for the first time to detect norephinephrine (141 pg/mL) and dopamine (262 pg/mL) in human cerebrospinal fluid.