Publications by authors named "Schmeichel A"

Article Synopsis
  • α-synucleinopathies, like Parkinson's disease, involve the misfolding and clumping of α-synuclein proteins, which can be difficult to detect in common samples like blood due to inhibitors.
  • * Recent advancements in a technique called Nanoparticle-enhanced Quaking-induced Conversion (Nano-QuIC) have shown that it can speed up detection of misfolded α-synuclein and improve sensitivity by 100 times compared to traditional methods.
  • * Nano-QuIC has demonstrated effectiveness in identifying low concentrations of misfolded proteins in blood samples from Parkinson's patients, paving the way for noninvasive blood tests that could lead to earlier diagnosis and better disease management.
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Purpose: To quantify sweat gland nerve fiber density in adolescents with diabetes. Additionally, to investigate associations between sudomotor innervation, sweat responses, and possible risk factors for sudomotor neuropathy.

Methods: Cross-sectional study where 60 adolescents with type 1 diabetes (duration > 5 years) and 23 control subjects were included.

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Purpose: There is a critical need for reliable diagnostic biomarkers as well as surrogate markers of disease progression in multiple system atrophy (MSA). Neurofilament light chain (NfL) has been reported to potentially meet those needs. We therefore sought to explore the value of NfL in plasma (NfL-p) in contrast to cerebrospinal fluid (NfL-c) as a diagnostic marker of MSA, and to assess NfL-p and NfL-c as markers of clinical disease progression.

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Purpose There is a critical need for reliable diagnostic biomarkers as well as surrogate markers of disease progression in multiple system atrophy (MSA). Neurofilament light chain (NfL) has been reported to potentially meet those needs. We therefore sought to explore the value of NfL in plasma (NfL-p) in contrast to CSF (NfL-c) as diagnostic marker of MSA, and to assess NfL-p and NfL-c as markers of clinical disease progression.

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Accumulation of amyloid-beta (Aβ) into amyloid plaques and hyperphosphorylated tau into neurofibrillary tangles (NFTs) are pathological hallmarks of Alzheimer's disease (AD). There is a significant intra- and inter-individual variability in the morphology and conformation of Aβ aggregates, which may account in part for the extensive clinical and pathophysiological heterogeneity observed in AD. In this study, we sought to identify an array of fluorescent dyes to specifically probe Aβ aggregates, in an effort to address their diversity.

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Spinal cord injury (SCI) results in cell death, demyelination, and axonal loss. The spinal cord has a limited ability to regenerate, and current clinical therapies for SCI are not effective in helping promote neurologic recovery. We have developed a novel scaffold biomaterial that is fabricated from the biodegradable hydrogel oligo(poly(ethylene glycol)fumarate) (OPF).

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Objective: To explore the role of alpha-synuclein (αSyn) oligomers and neurofilament light chain (NfL) in cerebrospinal fluid (CSF) of patients with pure autonomic failure (PAF) as markers of future phenoconversion to multiple system atrophy (MSA).

Methods: Well-characterized patients with PAF (n = 32) were enrolled between June 2016 and February 2019 at Mayo Clinic Rochester and followed prospectively with annual visits to determine future phenoconversion to MSA, Parkinson's disease (PD), or dementia with Lewy bodies (DLB). ELISA was utilized to measure NfL and protein misfolding cyclic amplification (PMCA) to detect αSyn oligomers in CSF collected at baseline.

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Positively charged oligo(poly(ethylene glycol) fumarate) (OPF+) hydrogel scaffolds, implanted into a complete transection spinal cord injury (SCI), facilitate a permissive regenerative environment and provide a platform for controlled observation of repair mechanisms. Axonal regeneration after SCI is critically dependent upon nutrients and oxygen from a newly formed blood supply. Our objective was to investigate fundamental characteristics of revascularization in association with the ingrowth of axons into hydrogel scaffolds, thereby defining spatial relationships between axons and the neovasculature.

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Study Objectives: Multiple system atrophy (MSA) is associated with disturbances in cardiovascular, sleep and respiratory control. The lateral paragigantocellular nucleus (LPGi) in the ventrolateral medulla (VLM) contains GABAergic neurons that participate in control of rapid eye movement (REM) sleep and cardiovagal responses. We sought to determine whether there was loss of putative GABAergic neurons in the LPGi and adjacent regions in MSA.

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Objective: To explore the role of alpha-synuclein (αSyn) oligomers and neurofilament light chain (NFL) in cerebrospinal fluid (CSF) as markers of early multiple system atrophy (MSA) and to contrast findings with Lewy body synucleinopathies.

Methods: In a discovery cohort of well-characterized early MSA patients (n = 24) and matched healthy controls (CON, n = 14), we utilized enzyme-linked immunosorbent assay to measure NFL and protein misfolding cyclic amplification (PMCA) to detect αSyn oligomers in CSF. We confirmed findings in a separate prospectively enrolled cohort of patients with early MSA (n = 38), Parkinson disease (PD, n = 16), and dementia with Lewy bodies (DLB, n = 13), and CON subjects (n = 15).

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Mechano growth factor (MGF) is an alternatively spliced form of insulin-like growth factor-1 (IGF-1) that has shown to be neuroprotective against 6-hydroxydopamine toxicity and ischemic injury in the brain. MGF also induces neural stem cell proliferation in the hippocampus and preserves olfactory function in aging mice. Cisplatin is a chemotherapy drug that induces peripheral neuropathy in 30-40% of treated patients.

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Synucleinopathies are neurodegenerative diseases that are associated with the misfolding and aggregation of α-synuclein, including Parkinson's disease, dementia with Lewy bodies and multiple system atrophy. Clinically, it is challenging to differentiate Parkinson's disease and multiple system atrophy, especially at the early stages of disease. Aggregates of α-synuclein in distinct synucleinopathies have been proposed to represent different conformational strains of α-synuclein that can self-propagate and spread from cell to cell.

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Article Synopsis
  • This study aimed to investigate the safety and efficacy of intrathecal mesenchymal stem cells (MSCs) as a treatment for multiple system atrophy (MSA) in patients at an early stage of the disease.
  • Twenty-four patients received varying doses of adipose-derived autologous MSCs, showing that the treatment was generally safe but caused some low back pain in a few cases, especially at higher doses.
  • The results indicated that the rate of disease progression in patients treated with MSCs was significantly lower than a control group, suggesting potential benefits that warrant further research in a placebo-controlled trial.
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Skin biopsies have gained increasing popularity as a tool to evaluate disorders affecting small nerve fibers. While reports on sweat gland nerve fiber density (SGNFD) to quantitate sudomotor innervation have been promising, methodologies vary significantly. Although conventional stereology is commonly used, no standard technique has been established.

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Hydrogel scaffolds provide a beneficial microenvironment in transected rat spinal cord. A combinatorial biomaterials-based strategy provided a microenvironment that facilitated regeneration while reducing foreign body reaction to the three-dimensional spinal cord construct. We used poly lactic-co-glycolic acid microspheres to provide sustained release of rapamycin from Schwann cell (SC)-loaded, positively charged oligo-polyethylene glycol fumarate scaffolds.

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Background: Accumulation of α-synuclein in multiple system atrophy (MSA) affects medullary autonomic and respiratory control areas, including the rostral ventrolateral medulla and raphe nuclei. Relative neuronal vulnerability and its relationship to α-synuclein accumulation in these areas are unknown. The aim of this study was to determine the extent of loss of adrenergic neurons in the rostral ventrolateral medulla and serotonergic neurons in the ventrolateral medulla and raphe nuclei and its relationship with α-synuclein accumulation.

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Background: Histaminergic neurons of the tuberomammillary nucleus are critical for maintenance of wakefulness and participate in basal ganglia modulation and sympathoexcitation. All of these functions are affected in multiple system atrophy and dementia with Lewy bodies.

Objectives: To determine the involvement of histaminergic neurons in these synucleinopathies.

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Multiple system atrophy is a sporadic alpha-synucleinopathy that typically affects patients in their sixth decade of life and beyond. The defining clinical features of the disease include progressive autonomic failure, parkinsonism, and cerebellar ataxia leading to significant disability. Pathologically, multiple system atrophy is characterized by glial cytoplasmic inclusions containing filamentous alpha-synuclein.

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Positively charged oligo[poly(ethylene glycol) fumarate] (OPF+) scaffolds loaded with Schwann cells bridge spinal cord injury (SCI) lesions and support axonal regeneration in rat. The regeneration achieved is not sufficient for inducing functional recovery. Attempts to increase regeneration would benefit from understanding the effects of the scaffold and transplanted cells on lesion environment.

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We used double immunocytochemistry for α-synuclein and markers of sympathoexcitatory neurons, oligodendrocytes, iron metabolism, and autophagy to study putative neuropathological interactions in multiple system atrophy. We focused in the rostral ventrolateral medulla as a prototype vulnerable region. We found that loss of C1 neurons and oligodendrocytes related to glial cytoplasmic inclusion accumulation, downregulation of iron transport, and upregulation of autophagy and ferritin expression in these area.

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Background Context: Traumatic injuries occurring at the conus medullaris of the spinal cord cause permanent damage both to the central nervous system and to the cauda equina nerve roots.

Purpose: This proof-of-concept study was to determine whether implanting the nerve roots into a biodegradable scaffold would improve regeneration after injury.

Methods: All experimental works involving rats were performed according to the approved guidelines by the Mayo Clinic Institutional Animal Care and Use Committee.

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Background: Respiratory dysfunction, including sleep disordered breathing, is characteristic of multiple system atrophy (MSA) and may reflect degeneration of brainstem respiratory nuclei involved in respiratory rhythmogenesis and chemosensitivity, including the pre-Bötzinger complex (preBötC), nucleus raphe pallidus (RPa), and nucleus raphe obscurus (ROb). However, impaired ventilatory responses to hypercapnia have also been reported in dementia with Lewy bodies (DLB), suggesting that these nuclei may also be affected in DLB.

Objectives: To determine whether there is involvement of the preBötC, RPa, and ROb in DLB.

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Unlabelled: Multiple system atrophy (MSA) is associated with respiratory dysfunction, including sleep apnea, respiratory dysrhythmia, and laryngeal stridor. Neurons of the parabrachial nucleus (PBN) control respiratory rhythmogenesis and airway resistance.

Objectives: The objective of this study is to determine whether there was involvement of putative respiratory regions of the PBN in MSA.

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Objective: To determine the pathologic substrates in patients with rapid eye movement (REM) sleep behavior disorder (RBD) with or without a coexisting neurologic disorder.

Methods: The clinical and neuropathologic findings were analyzed on all autopsied cases from one of the collaborating sites in North America and Europe, were evaluated from January 1990 to March 2012, and were diagnosed with polysomnogram (PSG)-proven or probable RBD with or without a coexisting neurologic disorder. The clinical and neuropathologic diagnoses were based on published criteria.

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Background: Multiple system atrophy (MSA) is a sporadic progressive neurodegenerative disorder characterised by autonomic failure, manifested as orthostatic hypotension or urogenital dysfunction, with combinations of parkinsonism that is poorly responsive to levodopa, cerebellar ataxia and corticospinal dysfunction. Published autopsy confirmed cases have provided reasonable neurological characterisation but have lacked adequate autonomic function testing.

Objectives: To retrospectively evaluate if the autonomic characterisation of MSA is accurate in autopsy confirmed MSA and if consensus criteria are validated by autopsy confirmation.

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