Parkinson’s disease is a neurodegenerative disorder characterized by the loss of motor skills and cognitive impairment. The hallmark of this disease is the presence of Lewy bodies in the substantia nigra of the brain, where the accumulation of alpha-synuclein amyloid fibrils lead to the death of dopaminergic neurons. Understanding the factors influencing AS aggregation and developing effective strategies for its inhibition is of paramount importance for developing potential therapeutic interventions. Previous studies suggest that flavonoids in green and black tea have neuroprotective properties that decrease the fibrillization rate of AS. This thesis investigates the inhibitory effects of two flavonoids coming from green and black tea, namely: EGCG, TFDG, and HSA on AS aggregation, shedding light on their potential as therapeutic candidates. The study employed a combination of biochemical and biophysical experimental techniques to elucidate the inhibitory mechanisms of EGCG, TFDG, and HSA on AS aggregation. Initial experiments involved the characterization of AS fibrillation kinetics using ThT assays, TEM, and CD. Results revealed that flavonoids exhibited similar inhibitory effects on AS aggregation, with more than 90% inhibitory potency. Interestingly, when aggregated AS was exposed to EGCG or TFDG, the amyloid fibrils changed conformation and formed non-toxic amorphous oligomers. The 13C-detected NMR experiments, adapted to probe the AS dynamic conformation and interactions at the atomic level at physiologically relevant conditions, further provided insights into the binding interactions between flavonoids and AS, revealing interaction with hydrophobic residues involved in the inhibition process. Furthermore, the role of HSA, a major protein component of the blood plasma, in modulating α-synuclein aggregation in the presence of tea-derived flavonoids was investigated. The study demonstrated, in line with the previous reports, that HSA can significantly suppress AS fibrillation, and moreover, the presence of HSA further enhances the flavonoids’ inhibitory effect. My findings provide valuable atomic level mechanistic insights into the inhibitory effects of EGCG and TFDG on alpha-synuclein aggregation. The comprehensive spectroscopic and biophysical investigation provides a solid foundation for further developing flavonoid-based inhibitors, subsequently drug candidates blocking the AS toxic oligomers formation and aggregation.

Electrochemical biosensors have been used to detect biomarkers sensitively at low limits of detection. The organic electrochemical transistor (OECT) is a special class of electrochemical biosensors characteristically known for its intrinsic amplification abilities. Nevertheless, if the biosensor is to be used with real clinical samples a strategy aiming to increase the specificity of the device other than the dependance on the respective biorecognition unit is necessary to minimize, if not eliminate, interference from foulants in complex biological media. In this work we test the antifouling performance of several Poly(ethylene glycol) based SAMs using Electrochemical impedance spectroscopy (EIS). We also evaluate the overall performance of the device and its ability to detect total α-synuclein, its aggregate and phosphorylated forms spiked in heat-inactivated human serum. Limits of detection in the fM and aM ranges were achieved.

No description available.

Objective: The purpose of this project was to develop evidence‐based clinical practice guidelines (CPGs) for the management of oral health (OH) for patients with Parkinson’s disease (PD). Background: Individuals with PD have significantly poorer OH than the general population. Poor OH is a risk factor for systemic diseases, including cardiovascular disease, diabetes, and respiratory infections. Materials and Methods: After an extensive literature review was completed, available evidence was evaluated for inclusion in the initial draft of the guidelines. The draft was then reviewed for content validity by experts in the areas of dentistry, dental hygiene and neurology using the Delphi method. After consensus among the content experts, final guidelines were completed. The final CPG was presented to individuals with PD and their caregivers at a support group. Participants were asked to review the information in the guidelines for 2 weeks and then submit a survey regarding the usefulness of the CPG. The CPG was also evaluated by practicing nurse practitioners (NPs) and dental hygienists using the AGREE II tool. Results: Twenty people from the PD support group participated in the educational intervention, and surveys were received from 14 participants. Overall, participants agreed or strongly agreed with each statement related to the applicability and usefulness of the guidelines. The CPG was evaluated using the AGREE II tool, and scores were >80% in all domains with an overall score of 97.1%. Conclusion: Development of these guidelines represent an initial step in improving the oral health and overall health of individuals with PD.

Parkinson's disease, a disorder involving the excitatory-inhibitory functions of the basal ganglia, develops to a stage where the muscles used for respiration, phonation and articulation in speech appear affected by a decreased range of motion. Parkinson speech is characterized by reduced intensity, monoloudness, weak overall effort and reduced intraoral pressures. Reports also indicate that reduced vocal intensity is a deterrent to oral communication in patients with Parkinson's disease. The study sought to examine the effects of singing "stimulative" and "sedative" songs to ascertain if different types of music affect articulatory precision in persons with Parkinson's disease. Articulatory precision was divided into six categories: rate, rhythm, initial consonants, final consonants, continuity, and intelligibility. Eighteen individuals with Parkinson's disease whose ages ranged from 52 to 84 years, who demonstrated limited range of movement of oral and facial muscles and possessed normal hearing, participated in this study. Participants were asked to sing two short, familiar songs a cappella. One song was of a sedative nature (slow and soft). The other was of a stimulative nature (fast and loud). One paragraph of The Rainbow Passage was read before and after the sedative song for each participant and again before and after the stimulative song. The data in one category was significant and most of the speech samples were affected by the music conditions. Statistically significant scores were found when comparing the post-test scores for initial consonants after the slow and fast songs. Finding a significant difference in scores under these parameters shows the effects music has on speech and the possibilities for future studies. The two categories of articulatory precision that remained the same from pre-test to post-test, intelligibility and final consonants, did so after different treatments and mean post-test scores for rate was not affected by the treatments.

Research has documented the positive effects of physical therapy as a treatment for limb motor symptoms associated with Parkinson's disease (PD). Previous studies have shown that speech and voice measures can be reflective of overall cardiovascular health and fitness in young, middle-aged, and older adults. In healthy individuals, increased respiratory drive has been found to influence vocal function and speech articulation. The rationale for the present study was that improved lower limb function might lead to improvements in overall fitness, which then may influence speech in individuals with Parkinson's disease. To investigate this premise, 10 participants diagnosed with mild to moderate idiopathic PD were involved in an intensive lower limb training program called Resistance Exercise via Negative-Eccentric Work (RENEW). The speech of the participants was recorded before and after the RENEW treatment in both medication-on and medication-off conditions. Following treatment there was a statistically significant increase in spirantization of the stop gap in DDK repetition in the medication-on condition and a decrease in diphthong duration in the medication-off condition. After treatment in the medication-on condition there was an increase in spirantization and a reduction in first and second formant transitions for the diphthong /ɔI/ compared to the medication-off condition. These results represented a slight worsening of articulatory precision and movement following treatment in response to PD medication. Overall, the present study found that intensive lower limb training did not influence the acoustic measures of speech articulation examined in the present study.

One of the main characteristics of Parkinson's disease (PD) is an exaggerated oscillatory activity in the beta band (12-30 Hz). This activity has been linked to the rise of symptoms such as bradykinesia and akinesia. Even if dopamine replacement therapy (oral intake of dopamine pro-drug levodopa) reverses these symptoms, the effect of the treatment on the beta band activity has still not been completely understood. Therefore, here the temporal dynamics of beta band activity in human patients affected by PD were characterized with and without levodopa treatment. Local-field-potential (LFP) recordings from five patients undergoing dopamine replacement therapy were used. From the LFPs, the extracted beta epochs with significantly higher power than expected from a comparable noisy signal were analyzed. This analysis showed that beta band activity occurred in bursts meaning that high amplitude oscillation alternated with silenced periods. The pathological state also distinguished itself for longer epochs and with power that increased with the length of the epoch. The administration of levodopa reduced the duration of bursts and decreased the overall mean power of the beta band activity. Finally, epochs with the same number of cycles were compared. The Coefficient of Variation prior such epochs suggested that the ongoing activity might lock into a synchronization process prior the burst. These results provide important information to better understand how levodopa alleviates some of the symptoms of PD and pave the way to develop better computational models for the emergence of beta oscillations.

京都大学 / 新制・論文博士 / 博士(医学) / 乙第13525号 / 論医博第2271号 / 新制||医||1062(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 井上 治久, 教授 大森 孝一, 教授 古川 壽亮 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

Parkinson’s disease (PD) is a neurological disorder characterized by the lack of functional dopaminergic neurons in the nigrostriatal pathway in the brain. Current therapeutic strategies for the disease provide temporary symptomatic relief. Gene therapy has the potential to improve dopamine production in Parkinson’s disease patients. Adeno-associated viruses (AAV) are the vectors of choice in gene therapy for PD, due to their well-characterized safety and efficacy profiles, with all primary receptors being glycans. The problem with using AAV in PD gene therapy is that the aged brain is resistant to transduction of the virus, while PD primarily occurs with age. Thus, in Aim 1 we characterize the age-related changes in glycan receptors in the nigrostriatal pathway as a baseline to address current challenges in gene delivery in Parkinson’s disease. To make these measurements from specific regions of tissue, we develop a platform that incorporates on-slide digestion followed by LC-MS/MS for integrated glycomics and proteomics. Further, we apply this to understand aging- and PD-related changes in the human pre-frontal cortex in Aims 2 and 3, to understand normal and pathological aging processes as well as integrate this information with transcriptomics data, to assess risk factors that may contribute to Parkinson’s disease. Finally, we also apply the method to investigate cancer premalignancy and heterogeneity. Our on-slide method, used herein to study aging, Parkinson’s disease and cancer, can be applied to any precious biopsy specimens to enable glycomic and proteomic profiling in diverse diseases, and thus may have a broad impact on biomedical research.

Few biological systems are as ubiquitous as the circadian rhythm, a distributed yet inter-connected “system of systems” that coordinates the timing of physiological processes via a self-regulating, flexible network present at every level of biological organization, from cells to cities. Its functional role as the interface between time-dependent internal processes and external environmental cues exposes the circadian rhythm to disruption if these drift out of synchrony. This is especially common in industrialized human societies, where the abun-dance of resources – in combination with the fact that anthropogenic calendars have largely supplanted the sun as the primary determinant of our daily cycles of rest, activity, and sleep – disrupts the circadian rhythm’s ability to synchronize biological processes with each other and the geophysical solar day. Humans are now beholden to two increasingly disconnected clocks, and the ever-accelerating curve of human progress suggests our biological and so-cial times will only grow more disconnected. Longitudinal “out-of-clinic” monitoring is an ecologically valid alternative to well-controlled laboratory studies that can provide insight into how human circadian and behav-ioral rhythms exist in day-to-day life, and so has great potential to provide contextual data for translating chronobiological science into clinical intervention. However, methodological diversity, inconsistent terminology, insufficient reporting, and the sheer number of potential factors has slowed progress. Herein is presented scientific work focused on detecting and quantifying some of these factors, particularly “sociogenic” determinants such as the seven-day week. Through rhythmometric analysis of longitudinal in-home actigraphy, weekly be-havioral patterns were observed in both young adult males (n = 24, mean age = 23.46 years) and older adults with Parkinson’s disease (n = 13 [7 male], mean age = 60.62 years, mean Hoehn & Yahr Stage = 2.31) that evince a seven-day “circaseptan” rhythm of circadi-an and sleep disruption. This is hypothesized to be dependent upon the seven-day calendar week, particularly the regular and abrupt shifts in timing between work and rest days. These perturbations vary by chronotype in young adults, and by disease severity in Parkin-son’s disease. Collectively, these results contribute to the growing evidence that our daily rhythms are shaped by sociogenic factors in addition to well-documented environmental and biological mechanisms. Moreover, the study of these subtle infradian patterns presents serious – yet surmountable – methodological challenges that must be overcome in order to accurately monitor, quantify, analyze, report, and apply findings from observational studies of naturalistic human behavior to scientific and clinical problems.