Abstract
Background
Death certificate (DC) errors are common. At our institution, all deaths have a preliminary death certificate (PDC) written by a clinician and then revised by a pathologist prior ...to the clinician signing the final death certificate (FDC). In autopsy cases, the FDC is signed by the pathologist who performs the autopsy.
Methods
A total of 100 in-hospital deaths (50 with autopsy and 50 without) occurred in 2020 were arbitrarily selected from a tertiary care center. All PDCs and FDCs were compared to identify/classify errors as major (incorrect cause of death (COD) or significant contributing factors) or minor (abbreviations, inappropriate non-essential contributing factors, immediate/intermediate COD errors). Frequency of PDC errors was compared by autopsy status, duration of hospital stay and PDC author.
Results
Ninety percent of cases had at least one PDC error and 39% had a major error. Major errors were more common in autopsy cases (50% versus 28%, P = 0.035), although minor/overall errors were not. Error rates did not significantly differ for the other variables assessed.
Conclusions
There is significance of having a pathologist review and revise DCs before they are signed. The increased frequency in major errors in cases with autopsy suggests that autopsy findings provided additional information to elucidate COD.
Amyloid-β (Aβ) fibrils in neuritic plaques are a hallmark of Alzheimer’s disease (AD). Since the 42-residue Aβ (Aβ42) fibril is the most pathogenic among different Aβ species, its structural ...characterization is crucial to our understanding of AD. While several polymorphs have been reported for Aβ40, previous studies of Aβ42 fibrils prepared at neutral pH detected essentially only one structure, with an S-shaped β-sheet arrangement (e.g., Xiao et al. Nat. Struct. Mol. Biol. 2015, 22, 499 ). Herein, we demonstrate the feasibility of characterizing the structure of trace amounts of brain-derived and synthetic amyloid fibrils by sensitivity-enhanced 1H-detected solid-state NMR (SSNMR) under ultrafast magic angle spinning. By taking advantage of the high sensitivity of this technique, we first demonstrate its applicability for the high-throughput screening of trace amounts of selectively 13C- and 15N-labeled Aβ42 fibril prepared with ∼0.01% patient-derived amyloid (ca. 4 pmol) as a seed. The comparison of 2D 13C/1H SSNMR data revealed marked structural differences between AD-derived Aβ42 (∼40 nmol or ∼200 μg) and synthetic fibrils in less than 10 min, confirming the feasibility of assessing the fibril structure from ∼1 pmol of brain amyloid seed in ∼2.5 h. We also present the first structural characterization of synthetic fully protonated Aβ42 fibril by 1H-detected 3D and 4D SSNMR. With procedures assisted by automated assignments, main-chain resonance assignments were completed for trace amounts (∼42 nmol) of a fully protonated amyloid fibril in the 1H-detection approach. The results suggest that this Aβ42 fibril exhibits a novel fold or polymorph structure.
Human presequence protease (hPreP) is an M16 metalloprotease localized in mitochondria. There, hPreP facilitates proteostasis by utilizing an ∼13,300-Å3 catalytic chamber to degrade a diverse array ...of potentially toxic peptides, including mitochondrial presequences and β-amyloid (Aβ), the latter of which contributes to Alzheimer disease pathogenesis. Here, we report crystal structures for hPreP alone and in complex with Aβ, which show that hPreP uses size exclusion and charge complementation for substrate recognition. These structures also reveal hPreP-specific features that permit a diverse array of peptides, with distinct distributions of charged and hydrophobic residues, to be specifically captured, cleaved, and have their amyloidogenic features destroyed. SAXS analysis demonstrates that hPreP in solution exists in dynamic equilibrium between closed and open states, with the former being preferred. Furthermore, Aβ binding induces the closed state and hPreP dimerization. Together, these data reveal the molecular basis for flexible yet specific substrate recognition and degradation by hPreP.
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•We report crystal structures for human presequence protease alone and in complex with Aβ•HPreP substrates are selected by size, shape, and charge distribution•The hPreP catalytic chamber recognizes and destroys Aβ amyloidogenicity•SAXS reveals hPreP open states and substrate binding dynamics
Human presequence protease is a mitochondrial Aβ-degrading enzyme whose molecular operating logic is largely uknown. King et al. reveal how this enzyme undergoes a closed-to-open transition to capture substrates, followed by specific recognition and destruction of peptide amyloidogenicity.
Alzheimer's disease is characterized by neuritic plaques, the main protein components of which are β-amyloid (Aβ) peptides deposited as β-sheet-rich amyloid fibrils. Cerebral Amyloid Angiopathy (CAA) ...consists of cerebrovascular deposits of Aβ peptides; it usually accompanies Alzheimer's disease, though it sometimes occurs in the absence of neuritic plaques, as AD also occurs without accompanying CAA. Although neuritic plaques and vascular deposits have similar protein compositions, one of the characteristic features of amyloids is polymorphism, i.e., the ability of a single pure peptide to adopt multiple conformations in fibrils, depending on fibrillization conditions. For this reason, we asked whether the Aβ fibrils in neuritic plaques differed structurally from those in cerebral blood vessels. To address this question, we used seeding techniques, starting with amyloid-enriched material from either brain parenchyma or cerebral blood vessels (using meninges as the source). These amyloid-enriched preparations were then added to fresh, disaggregated solutions of Aβ to make replicate fibrils, as described elsewhere. Such fibrils were then studied by solid-state NMR, fiber X-ray diffraction, and other biophysical techniques. We observed chemical shift differences between parenchymal vs. vascular-seeded replicate fibrils in select sites (in particular, Ala2, Phe4, Val12, and Gln15 side chains) in two-dimensional
C-
C correlation solid-state NMR spectra, strongly indicating structural differences at these sites. X-ray diffraction studies also indicated that vascular-seeded fibrils displayed greater order than parenchyma-seeded fibrils in the "side-chain dimension" (~ 10 Å reflection), though the "hydrogen-bond dimensions" (~ 5 Å reflection) were alike. These results indicate that the different nucleation conditions at two sites in the brain, parenchyma and blood vessels, affect the fibril products that get formed at each site, possibly leading to distinct pathophysiological outcomes.
Abstract
Limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC) is a dementia-related proteinopathy common in the elderly population. LATE-NC stages 2 or 3 are ...consistently associated with cognitive impairment. A condensed protocol (CP) for the assessment of Alzheimer disease neuropathologic change and other disorders associated with cognitive impairment, recommended sampling of small brain portions from specific neuroanatomic regions that were consolidated, resulting in significant cost reduction. Formal evaluation of the CP for LATE-NC staging was not previously performed. Here, we determined the ability of the CP to identify LATE-NC stages 2 or 3. Forty brains donated to the University of Washington BioRepository and Integrated Neuropathology laboratory with known LATE-NC status were resampled. Slides containing brain regions required for LATE-NC staging were immunostained for phospho-TDP-43 and reviewed by 6 neuropathologists blinded to original LATE-NC diagnosis. Overall group performance distinguishing between LATE-NC stages 0–1 and 2–3 was 85% (confidence interval CI: 75%–92%). We also used the CP to evaluate LATE-NC in a hospital autopsy cohort, in which LATE-NC was more common in individuals with a history of cognitive impairment, older age, and/or comorbid hippocampal sclerosis. This study shows that the CP can effectively discriminate higher stages of LATE-NC from low or no LATE-NC and that it can be successfully applied in clinical practice using a single tissue block and immunostain.
Diffuse midline glioma, H3 K27-altered (DMG-H3 K27) is an aggressive group of diffuse gliomas that predominantly occurs in pediatric patients, involves midline structures, and displays loss of H3 ...p.K28me3 (K27me3) expression by immunohistochemistry and characteristic genetic/epigenetic profile. Rare examples of a diffuse glioma with an H3 p.K28M (K27M) mutation and without involvement of the midline structures, so-called "diffuse hemispheric glioma with H3 p.K28M (K27M) mutation" (DHG-H3 K27), have been reported. Herein, we describe 2 additional cases of radiologically confirmed DHG-H3 K27 and summarize previously reported cases. We performed histological, immunohistochemical, molecular, and DNA methylation analysis and provided clinical follow-up in both cases. Overall, DHG-H3 K27 is an unusual group of diffuse gliomas that shows similar clinical, histopathological, genomic, and epigenetic features to DMG-H3 K27 as well as enrichment for activating alterations in MAPK pathway genes. These findings suggest that DHG-H3 K27 is closely related to DMG-H3 K27 and may represent an unusual presentation of DMG-H3 K27 without apparent midline involvement and with frequent MAPK pathway activation. Detailed reports of additional cases with clinical follow-up will be important to expand our understanding of this unusual group of diffuse gliomas and to better define the clinical outcome and how to classify DHG-H3 K27.
The coronavirus disease 19 (COVID-19) pandemic is placing unparalleled burdens on regional and institutional resources in medical facilities across the globe. This disruption is causing unprecedented ...downstream effects to traditionally established channels of patient care delivery, including those of essential anatomic pathology services. With Washington state being the initial North American COVID-19 epicenter, the University of Washington in Seattle has been at the forefront of conceptualizing and implementing innovative solutions in order to provide uninterrupted quality patient care amidst this growing crisis.
To conduct a rapid validation study assessing our ability to reliably provide diagnostic neuropathology services via a whole slide imaging (WSI) platform as part of our departmental COVID-19 planning response.
This retrospective study assessed diagnostic concordance of neuropathologic diagnoses rendered via WSI as compared to those originally established via traditional histopathology in a cohort of 30 cases encompassing a broad range of neurosurgical and neuromuscular entities. This study included the digitalization of 93 slide preparations, which were independently examined by groups of board-certified neuropathologists and neuropathology fellows.
There were no major or minor diagnostic discrepancies identified in either the attending neuropathologist or neuropathology trainee groups for either the neurosurgical or neuromuscular case cohorts.
Our study demonstrates that accuracy of neuropathologic diagnoses and interpretation of ancillary preparations via WSI are not inferior to those generated via traditional microscopy. This study provides a framework for rapid subspecialty validation and deployment of WSI for diagnostic purposes during a pandemic event.
Pineal anlage tumor is a rare pediatric tumor with clinical and histological features overlapping with pineoblastoma. Two patients with pineal anlage tumor, a 13‐month‐old female and an 11‐month‐old ...male, underwent subtotal resection, high‐dose chemotherapy with autologous stem cell rescue, and radiation. Neither had tumor progression 50 months after diagnosis. The tumors underwent next‐generation sequencing on a panel of 340 genes. Chromosomal copy gains and losses were present and differed between the tumors. No mutations or amplifications, including none specific to pineoblastoma, were identified.
Seeding of amyloid fibrils into fresh solutions of the same peptide or protein in disaggregated form leads to the formation of replicate fibrils, with close structural similarity or identity to the ...original fibrillar seeds. Here we describe procedures for isolating fibrils composed mainly of β-amyloid (Aβ) from human brain and from leptomeninges, a source of cerebral blood vessels, for investigating Alzheimer's disease and cerebral amyloid angiopathy. We also describe methods for seeding isotopically labeled, disaggregated Aβ peptide solutions for study using solid-state NMR and other techniques. These methods should be applicable to other types of amyloid fibrils, to Aβ fibrils from mice or other species, tissues other than brain, and to some non-fibrillar aggregates. These procedures allow for the examination of authentic amyloid fibrils and other protein aggregates from biological tissues without the need for labeling the tissue.
A 47-year-old man who presented with subacute binocular diplopia and a left head turn was found to have a right sixth nerve palsy and right optic disc edema. Radiologic imaging revealed a non-lytic ...right greater sphenoid wing mass with a dural tail, suggestive of a sphenoid wing meningioma. The patient underwent an orbitotomy with lesion biopsy; histopathologic analysis and subsequent imaging revealed the diagnosis of metastatic clear cell renal cell carcinoma. He developed new metastases despite systemic immunotherapy, and prognosis was guarded at last follow up 3 months after diagnosis. The authors present the first reported case of renal cell carcinoma metastatic to the sphenoid wing without sinus involvement, describing an atypical presentation of an aggressive malignancy that necessitates timely diagnosis for possible survival.
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