Submitted in fulfilment of the requirements of Master's Degree in Chemistry, Durban University of Technology, 2017. / DNA damage plays a pivotal role in the pathogenesis of Alzheimer’s disease (AD) therefore, an innovative ss-DNA/dopamine/TiO2/FTO electrode strategy was developed to detect the genotoxicity upon photocatalytic reactions. This study involves a computational and electrochemical investigation towards the direct measurement of DNA damage. Computational chemistry was useful to resolve the intricate chemistry problems behind electrode constructions. The computational protocols were simultaneously carried out comprising of density functional theory (DFT) calculations, Metropolis Monte Carlo (MC) adsorption studies, and molecular dynamics (MD) simulations. The DFT calculations elucidated the structural, electronics, and vibrational properties of the electrode components resulting in a good agreement with the experimental parameters. The MC simulations carried out using simulated annealing predicted the adsorption process within layer-by-layer electrode as well generating reliable inputs prior to MD simulations. A 100 ns MD simulations were performed using a canonical ensemble provided information on the thermodynamics parameters such as total energy, temperature, and potential energy profiles, including radius of gyrations and atomic density profiles. Binding energies calculated from the MD trajectories revealed increasing interaction energies for the layer-by-layer electrode, in agreement with the electrochemical characterization studies (i.e. gradual decrease of cyclic voltammogram (CV) as well as increasing diameter of electrochemical impedance spectroscopy (EIS) semicircle upon electrode modification). The higher binding energies may lead to smaller changes in the electrochemical polarizability which directly affect to the decreasing of redox peak current and charge transfer resistance enhancement. Instead, HOMO-LUMO DFT levels are also taken into account to explain electron transfer phenomena within layer construction leading to the alteration of CV behaviours. Experimentally, the ss-DNA was electronically linked to TiO2/FTO surface through dopamine as a molecular anchor. Electrochemical measurements using cyclic voltammetry and EIS were employed to characterize the electrode modifications. The square wave voltammetry was subsequently used to measure the DNA damage and the potency of antioxidant treatment using ascorbic acid (AA) due to its ability in protecting the DNA from the damages. The presence of AA significantly protected the DNA from the damage, therefore was able to be used as a potential treatment in AD. Theoretically, guanine residues predicted by DFT as the most reactive sites of the ss-DNA involved in the genotoxic reactions. Overall, the theoretical studies successfully validated the experimental study as well as providing the molecular basis of interaction phenomena towards electrode constructions. Our results highlight the potential application of this methodology to screen the genotoxicity in Alzheimer’s, suggesting the important role of theoretical studies to predict the molecular interaction and validation of the DNA-based sensors and bioelectronics. / M

Alzheimer's disease is a devastating neurodegenerative disease eventually leading to dementia. An effective treatment does not yet exist. Here we show that oral application of the compound anle138b restores hippocampal synaptic and transcriptional plasticity as well as spatial memory in a mouse model for Alzheimer's disease, when given orally before or after the onset of pathology. At the mechanistic level, we provide evidence that anle138b blocks the activity of conducting Ab pores without changing the membrane embedded A beta-oligomer structure. In conclusion, our data suggest that anle138b is a novel and promising compound to treat AD-related pathology that should be investigated further.

There is an urgent need for the development of new therapeutic strategies for Alzheimer's disease (AD). The dual-specificity tyrosine phosphorylation-regulated kinase-1A (Dyrk1a) is a protein kinase that phosphorylates the amyloid precursor protein (APP) and tau and thus represents a link between two key proteins involved in AD pathogenesis. Furthermore, Dyrk1a is upregulated in postmortem human brains, and high levels of Dyrk1a are associated with mental retardation. Here, we sought to determine the effects of Dyrk1 inhibition on AD-like pathology developed by 3xTg-AD mice, a widely used animal model of AD. We dosed 10-month-old 3xTg-AD and nontransgenic (NonTg) mice with a Dyrk1 inhibitor (Dyrk1-inh) or vehicle for eight weeks. During the last three weeks of treatment, we tested the mice in a battery of behavioral tests. The brains were then analyzed for the pathological markers of AD. We found that chronic Dyrk1 inhibition reversed cognitive deficits in 3xTg-AD mice. These effects were associated with a reduction in amyloid-beta (Ab) and tau pathology. Mechanistically, Dyrk1 inhibition reduced APP and insoluble tau phosphorylation. The reduction in APP phosphorylation increased its turnover and decreased Ab levels. These results suggest that targeting Dyrk1 could represent a new viable therapeutic approach for AD.

Alzheimer´s disease (AD) is an age-related, irreversible and progressive neurodegenerative pathology that deteriorates cognitive function including learning and memory. AD is characterised neuropathologically by the presence of neuritic plaques (Aβ), neurofibrillary tangles (NFTs), synaptic loss and neuronal death. AD affects specific brain regions involved in mnestic function such as the neocortex and the hippocampus. The dorsal (DR) and the median raphe (MR) nuclei give rise to serotonergic (5-HT) projections that innervate multiple brain regions including the cortex and the hippocampus, playing an important role in learning and memory processes. For a long time the degeneration of cholinergic (ACh) system was considered as the main neurochemical changes in AD brains, however, more recent studies highlight the involvement of other neurotransmitter systems including 5-HT. This thesis entitled “Altered serotonergic neurotransmission as a main player in the pathophysiology of Alzheimer’s disease: structural and ultrastructural studies in a triple transgenic mouse model of the disease” demonstrates that there exist specific alterations in the serotonergic projections of the hippocampus during the progression of AD using the triple transgenic (3xTg-AD) mouse model of the disease, which closely resemble human AD. Mr. Harun N. Noristani is submitting this thesis to the University of Manchester for the degree of PhD in the Faculty of Life Science. The results obtained in this thesis show for the first time a biphasic increase in serotonergic fibre sprouting in the 3xTg-AD mouse model of AD that occurs in parallel with evident intraneuronal/extracellular Aβ deposition in the hippocampus (Chapter 3). In addition, serotonergic fibre sprouting correlated with reduced perforated synapses in the hippocampus, suggesting a structural remodeling process to maintain hippocampal connectivity (Chapter 4). Increased 5-HT neurotransmission (via high dietary intake of tryptophan, 5-HT precursor) reduced intraneuronal Aβ accumulation in the hippocampus, suggesting a direct role of 5-HT neurotransmission in modifying AD neuropathology (Chapter 5). Given the protective role of increased 5-HT neurotransmission, treatment with 5-HT enhancing drugs may be beneficial in reducing the underlying pathology as well as improving the behavioural and cognitive abnormalities associated with AD. Nevertheless, the role of specific 5-HT receptors responsible for such neuro-protective effect of 5-HT in AD awaits further research.

Inledning: År 2030 uppskattas det vara ungefär 230 000 stycken människor i Sverige somhar drabbats av någon typ av demenssjukdom. Sjukdomens stadier delas in i begynnande,mild, måttlig och svår demens. Där första symtomen i den begynnande fasen brukar vara attden drabbade inte kommer ihåg vart den lagt sina saker. I den svåra fasen av sjukdomen ärpatienten förmodligen beroende av dygnet runt vård, patienten brukar även ha svårt attprata, enstaka ord eller meningar brukar upprepas. Beteendemässiga och psykiska symtom(BPSD) hos demenssjuka är symtom som kan orsaka lidande hos patienten och dessanhöriga. Symtomen delas in i fyra undergrupper affektiva, psykossymtom, hyperaktivitetoch apati. Riskfaktorn med högst evidens är Apolipoprotein E (ApoE), ApoEε4-allelen.Riskfaktorer med lägre evidensgrad är t.ex. låg utbildning och släktskap. Sjukdomen orsakas av att nervcellerna i hjärnan dör, framförallt i delen av hjärnan därminnet sitter. En röntgen av hjärnan visar onormala proteininlagringar, amyloida plack.Amyloidhypotesen påstår att det blir en överproduktion av amyloid-beta proteinet vilken trosvara den patologiska händelsen vid Alzheimers sjukdom. Tauproteinet hyperfosfyleras till enisoform som är tre gånger större än i en frisk hjärna, om överproduktion av tau på specifikaställen eller hela hjärnan orsakar sjukdomen har forskarna inte kommit fram till ännu. Mildtill måttlig Alzheimers sjukdom behandlas med acetylkolinesterashämmarna donepezil,rivastagmin och galantamin. Svår Alzheimers sjukdom behandlas med en NMDAreceptoragonist,memantin. Syfte: Att undersöka om acetylkolinesterashämmare eller neuroleptika fungerar bäst vidsymtom som uppkommer vid BPSD, samt undersöka vilka biverkningar som är vanligast. Metod: PubMed har använts för att hitta studier som stämmer in på inklusionskriterierna.Studier som exkluderas är de som undersökt fel substans, fel indikation eller fel preparat t.ex.omega-3. Resultat: De vanligaste biverkningarna som rapporterats hos acetylkolinesterashämmarnaär bland annat illamående och kräkningar. Av neuroleptika preparaten verkar det varasömnighet som är den mest rapporterade biverkningen. Studierna som undersökteneuroleptika kom fram till ungefär samma sak, att preparaten kan förbättra symtomen. Av destudier som undersökte acetylkolinesterashämmarna var det tre studier som drog slutsatsenatt de kan ha effekt. En studie säger att det inte sågs någon skillnad mellan donepezil ochplacebo vid dessa typer av symtom. Diskussion: Då de olika studierna som använts i arbetet har undersökt olika effektmått hardet varit svårt att göra en rättvis bedömning om läkemedlen fungerar eller ej. Då i de flestafall bara gått och jämföra ett effektmått från studierna. Hade jag bestämt vilka effektmåttsom fick finnas i varje studie redan från början och sedan gjort en exkludering utifrån det,hade det varit enklare att jämföra studierna och därefter kommit fram till en bra slutsats. Viden jämförelse mellan de olika substanserna ur neuroleptikagruppen, är sömnighet denvanligaste biverkningen i tre av fyra grupper. Viktökning är också en av de vanligastebiverkningarna i två av grupperna där ungefär 32% drabbades av just denna biverkning.Varför patienterna ökat i vikt framgår inte i studierna. Slutsats: Acetylkolinesterashämmare och neuroleptika kan ha effekt vid symtom somuppkommer vid BPSD. Acetylkolinesterashämmarna bör provas i första hand om intebehandlingen redan är insatt.

This thesis presents a study exploring the lived experience of becoming cared for from the perspective of women with Alzheimer's disease (AD). The objectives of the study were to reveal the experience of receiving assistance with instrumental activities of daily living (IADL's) from the perspective of women with AD, to explore the care relationship between women and their spouses and to examine the changing role and identity of those women. Interpretative Phenomenological Analysis (IPA) was used as the methodology to explore the meaning given to becoming cared for. This methodology promotes the recognition of the unique ways individuals experience the world and is regularly used to better understand how illness affects behaviour and lifestyles. Eight women with AD took part in two semi-structured interviews and their transcripts were analysed individually, before exploring convergences and divergences across cases. Three key experiences emerged from the final analysis; 'It's a togetherness', 'Me being me' and 'Seeing cobwebs'. The findings identify becoming cared for as a relational phenomenon for the women, influenced by their experience of ongoing connections with their husbands. Some participants attempted to maintain their sense of self and womanhood in relation to completing IADL's, comparing their past selves to the present. However, this experience was often negatively affected by how others treated them. Other women viewed the changes they experienced in a more positive way, accepting becoming cared for as a part of life. There was a clear sense of contentment in their evolving lives, seeing beauty where they had not seen it before. This adds an alternative view to current literature, as some women appear to embrace the change in themselves when becoming cared for, rather than experiencing a loss of identity. Humanisation theory provides a conceptual framework to aid change in healthcare professional's practice, by encouraging them to regard women with AD as holistic human beings. Whilst change may be viewed by healthcare professionals as a negative symptom of AD, it should be considered that becoming cared for may be experienced as a positive transition in life.

The present study examined the concurrent validity of several proposed measures of premorbid IQ, present ability measures, and demographic variables at predicting intellectual, verbal memory, and language performance in a sample of 98 normal elderly Canadians (mean age = 71.9 years). Predictive regression equations were developed to estimate performance on criterion measures in each cognitive domain including general intellectual ability (i.e. Wechsler Adult Intelligence Scale-Revised Verbal IQ: WAIS-R VIQ), verbal memory (i.e. California Verbal Learning Test long delayed free recall: CVLTLDFR), and language domains (i.e. Boston Naming Test: BNT). These new regression equations utilized a combination of measures of premorbid VIQ and present ability measures to account for 63%, 32% and 54% of the variance in WAIS-R VIQ, CVLTLDFR, and BNT performance, respectively. The utility of these new equations for detecting impaired performance and cognitive decline in clinical samples was evaluated by calculation of sensitivity scores for each equation based on the method proposed by Graves, Carswell & Snow (in press). The results indicated that performance would have to decline by approximately 15 points for WAIS-R VIQ, 6 points for CVLTLDFR, and 6 points for BNT scores, to be reliably detected 80% of the time. The implications of the sensitivity of each of these equations was discussed with regard to the clinical application of these equations for predicting premorbid cognition in early Alzheimer's disease. The current study was also the first study to develop predictive regression equations utilizing measures of premorbid VIQ and present ability measures to estimate verbal memory and language performance in a healthy elderly sample. / Graduate

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Magister Pharmaceuticae - MPharm / The cascade of neurotoxic events involved in the pathogenesis of Alzheimer's disease may explain the inefficacy of currently available treatment based on acetylcholinesterase inhibitors (AChEI - donepezil, galantamine, rivastigmine) and N-methyl-D-aspartate (NMDA) antagonists (memantine). These drugs were designed based on the "one-moleculeone- target" paradigm and only address a single target. Conversely, the multi-target drug design strategy increasingly gains recognition. Based on the versatile biological activities of tacrine, trolox and β-carboline derivatives, the attention they have received as lead structures for the design of multifunctional drugs for the treatment of Alzheimer's disease, and the topology of the active site of AChE, we have designed tacrine-trolox and tacrine-tryptoline hybrids with various linker chain lengths. The aim with these hybrids was to provide additive or synergistic therapeutic effects that might help overcome the limitation of current anti Alzheimer's disease drugs. All synthesized compounds were designed from lead structures (tacrine, tryptoline and trolox) to obtain cholinesterase (ChE) multisite binders and multifunctional AD agents. The study was rationalized by docking all structures in the active site of TcAChE using Molecular Operating Environment (MOE) software before proceeding with the synthesis. ChE inhibition was assessed in a UV enzyme inhibition assay using Ellman's method. Antioxidant activities were assessed using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH.) absorbance assay. The hybrids containing the trolox moiety (compounds 8a-e) showed moderate to high AChE inhibitory activity in the nano to micro molar range (IC₅₀: 17.37 - 2200 nM), BuChE inhibition was observed in the same range (IC₅₀: 3.16 – 128.82 nM), and free radical scavenging activities in micro molar range (IC50: 11.48 – 49.23 µM). These are comparable or slightly higher than their reference compounds donepezil (AChE IC₅₀ = 220 nM), tacrine (BuChE IC₅₀: 14.12 nM), and trolox (DPPH IC₅₀: 17.57 µM). The hybrids with longer linker chain lengths, 6 and 8 carbons (8d and 8e), showed better ChE inhibitory activity than the shorter ones, 2, 3, and 4 carbons (8a-c respectively). This correlates well with literature. Free radical scavenging activities, however, seems not to be significantly affected by varying linker chain lengths. The hybrid compound (14) containing the tryptoline moiety linked with a 7 carbon spacer displayed the best AChE and BuChE inhibitory activity (IC₅₀ = 17.37 and 3.16 nM) but poor free radical scavenging activity. Novel anti-Alzheimer's disease drugs with multi-target neuroprotective activities were thus obtained and hybrid molecules that exhibit good ChE inhibition (8d, 8e and 14) and anti-oxidant (8d and 8e) activity were identified as suitable candidates for further investigation. / National Research Foundation (NRF)