846 research outputs found
Development of a high-throughput drug screening platform for oligodendrocyte myelination (for progressive multiple sclerosis)
Aim
As part of the broad strategy in Edinburgh and beyond to discover new treatments for
progressive Multiple Sclerosis (MS), the aims for my PhD project were: (1) to address the lack
of an in vitro phenotypic drug screening platform that is able to fully recapitulate myelin
sheath formation, with the long-term goal being to enhance the discovery of pro
remyelination therapies in progressive MS, and target the poor drug discovery rates in brain
disorders which is partially due to poor disease modelling, and (2) the exploration of non
linear optical imaging microscopy techniques that targets both the resolution and speed to
study myelination.
Background
In multiple sclerosis, an inflammatory autoimmune process destroys the oligodendrocytes
that provide neuronal support by forming multi-layered compact myelin sheaths around
axons, leading to neurodegeneration. Although there are drugs available to suppress the
inflammatory attack to limit the formation of demyelinated lesions, no treatments currently
exist to promote the regeneration of these myelin sheaths once the damage has occurred.
Cell based screens have formed an important part of the strategy used to discover such
regenerative drugs. The majority of published cell-based phenotypic drug screens to target
repair have focused on the differentiation of oligodendrocyte precursor cells into
oligodendrocytes rather than their ability to form mature protective myelin sheaths.
However, in many MS lesions, pre-myelinating oligodendrocytes are present, and studies on
oligodendrocyte biology show that differentiation and myelination are regulated by distinct
mechanisms. There is therefore a need for novel drug screens that target the later
myelinating stages of oligodendrocyte development.
Results
Using a 3D microfibre system for in vitro myelin sheath formation (described by Bechler,
Byrne and ffrench-Constant (2015)), I first asked whether compounds that had been
v
identified as increasing differentiation in conventional 2D culture systems enhanced
myelination in the 3D cultures. While Benztropine and Clemastine showed an increase in the
number of MBP+ (differentiated) oligodendrocytes in the 2D system, consistent with
previous publications, no increase in myelin sheath formation was seen with any of the drugs
in the 3D system, highlighting the potentially important differences between differentiation
and myelin sheath formation for drug discovery.
Next I developed a multiwell plate based assay to allow 3D myelination assays to be used for
drug screening. Using electrospinning to produce PLA microfibres, I was able to develop and
optimise a technique to insert and suspend the fibres across the bottom of a 96-well plate
that can be incorporated into an automated pipeline for high-throughput drug screening. The
3D myelin sheaths could be imaged using the Leica SP8 confocal system with the
MatrixScreener extension and the Opera Phenix high-content screening system.
Finally, I addressed the problem of imaging myelin in such screens. CARS was shown to be
able to preferentially detect myelin sheaths in fixed and live slices in regions and time-points
of varying myelin densities. As the development of new myelin sheaths requires the
formation of lipid and therefore the incorporation of hydrogen, the consumption of D2O (heavy water) with a 2H atom allowed the non-invasive labelling and detection of myelin
sheaths using SRS. Future experiments will allow us to confirm whether this deuterium
detection is preferential and/or specific to new myelin sheaths.
Significance
With only about 10% of drugs that enter Phase I trials successfully launching into clinics, there
is an important need for more effective drug screens that better model disease-relevant
processes and so reduce late-stage failures. The high-throughput-compatible 96-well plate
with suspended PLA microfibres that combines the recent progresses in 3D cellular model
systems with bioengineering and the recent advances in high content imaging systems may
give us the opportunity to more accurately model these disease-relevant structures in vitro,
and therefore improve drug discovery for regenerative therapies in multiple sclerosis and
other myelin diseases.
The research on Raman-based label-free imaging of myelin sheaths is not only applicable for
imaging myelin sheaths in the context of drug validation, but could be important for live imaging of brain slices and detection of newly-formed myelin sheaths without the need for
complex and expensive transgenic animals
Efficacy of Anticholinergics for Chronic Prostatitis/Chronic Pelvic Pain Syndrome in Young and Middle-Aged Patients: A Single-Blinded, Prospective, Multi-Center Study
Purpose Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) exhibits variable lower urinary tract symptoms (LUTS). The aim of this study was to evaluate the incidence of LUTS and the efficacy of an anticholinergic agent in young and middle-aged CP/CPPS patients. Methods Ninety-six men with CP/CPPS were randomly assigned in a single-blind fashion and received either ciprofloxacin (group 1, 49 patients) or ciprofloxacin and solifenacin (5 mg/day; group 2, 47 patients) for 8 weeks. The National Institutes of Health chronic prostatitis symptom index (NIH-CPSI), the International Prostate Symptom Score (IPSS), and the International Index of Erectile Function-5 (IIEF-5) were used to grade the patients' symptoms and the quality of life impact at the start of the study, and at 4 and 8 weeks from the initiation of the study. Results There was no significant difference between groups 1 and 2 with respect to age, duration of disease, or sub-domains of the IPSS, NIH-CPSI, or IIEF-5 at baseline. Of these patients, 67.4% had LUTS. Statistically significant differences were determined via the NIH-CPSI for total score and the pain and urinary domain scores. Statistically significant differences were determined via the IPSS for total score and the storage domain score. The total score of the IIEF-5 increased, but the change was not significant. There was no statistically significant difference in residual urine. Conclusions Many CP/CPPS patients had LUTS. Solifenacin in CP/CPPS demonstrated improvements in the NIH-CPSI and the IPSS total score and storage score. Storage factors significantly improved via the NIH-CPSI and IPSS assessments in the solifenacin treatment group
Disentangled representation learning for multilingual speaker recognition
The goal of this paper is to learn robust speaker representation for
bilingual speaking scenario. The majority of the world's population speak at
least two languages; however, most speaker recognition systems fail to
recognise the same speaker when speaking in different languages.
Popular speaker recognition evaluation sets do not consider the bilingual
scenario, making it difficult to analyse the effect of bilingual speakers on
speaker recognition performance. In this paper, we publish a large-scale
evaluation set named VoxCeleb1-B derived from VoxCeleb that considers bilingual
scenarios.
We introduce an effective disentanglement learning strategy that combines
adversarial and metric learning-based methods. This approach addresses the
bilingual situation by disentangling language-related information from speaker
representation while ensuring stable speaker representation learning. Our
language-disentangled learning method only uses language pseudo-labels without
manual information.Comment: Interspeech 202
Disentangled dimensionality reduction for noise-robust speaker diarisation
The objective of this work is to train noise-robust speaker embeddings
adapted for speaker diarisation. Speaker embeddings play a crucial role in the
performance of diarisation systems, but they often capture spurious information
such as noise and reverberation, adversely affecting performance. Our previous
work has proposed an auto-encoder-based dimensionality reduction module to help
remove the redundant information. However, they do not explicitly separate such
information and have also been found to be sensitive to hyper-parameter values.
To this end, we propose two contributions to overcome these issues: (i) a novel
dimensionality reduction framework that can disentangle spurious information
from the speaker embeddings; (ii) the use of a speech/non-speech indicator to
prevent the speaker code from representing the background noise. Through a
range of experiments conducted on four different datasets, our approach
consistently demonstrates the state-of-the-art performance among models without
system fusion.Comment: This paper was submitted to Interspeech202
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