935 research outputs found
Senile Systemic Amyloidosis: Clinical Features at Presentation and Outcome
Background Cardiac amyloidosis is a fatal disease whose prognosis and treatment rely on identification of the amyloid type. In our aging population transthyretin amyloidosis (ATTRwt) is common and must be differentiated from other amyloid types. We report the clinical presentation, natural history, and prognostic features of ATTRwt compared with cardiacâisolated AL amyloidosis and calculate the probability of disease diagnosis of ATTRwt from baseline factors.
Methods and Results All patients with biopsyâproven ATTRwt (102 cases) and isolated cardiac AL (36 cases) seen from 2002 to 2011 at the UK National Amyloidosis Center were included. Median survival from the onset of symptoms was 6.07 years in the ATTRwt group and 1.7 years in the AL group. Positive troponin, a pacemaker, and increasing New York Heart Association (NYHA) class were associated with worse survival in ATTRwt patients on univariate analysis. All patients with isolated cardiac AL and 24.1% of patients with ATTRwt had evidence of a plasma cell dyscrasia. Older age and lower Nâterminal proâBâtype natriuretic peptide (NT proâBNP) were factors significantly associated with ATTRwt. Patients aged 70 years and younger with an NT proâBNP <183 pmol/L were more likely to have ATTRwt, as were patients older than 70 years with an NT proâBNP <1420 pmol/L.
Conclusions Factors at baseline associated with a worse outcome in ATTRwt are positive troponin T, a pacemaker, and NYHA class IV symptoms. The age of the patient at diagnosis and NT proâBNP level can aid in distinguishing ATTRwt from AL amyloidosis
The complementary role of histology and proteomics for diagnosis and typing of systemic amyloidosis
The tissue diagnosis of amyloidosis and confirmation of fibril protein type, which are crucial for clinical management, have traditionally relied on Congo red (CR) staining followed by immunohistochemistry (IHC) using fibril protein specific antibodies. However, amyloid IHC is qualitative, non-standardised, requires operator expertise, and not infrequently fails to produce definitive results. More recently, laser dissection mass spectrometry (LDMS) has been developed as an alternative method to characterise amyloid in tissue sections. We sought to compare these techniques in a real world setting. During 2017, we performed LDMS on 640 formalin-fixed biopsies containing amyloid (CR+ve) comprising all 320 cases that could not be typed by IHC (IHCâve) and 320 randomly selected CR+ve samples that had been typed (IHC+ve). In addition, we studied 60 biopsies from patients in whom there was a strong suspicion of amyloidosis, but in whom histology was non-diagnostic (CRâve). Comprehensive clinical assessments were conducted in 532 (76%) of cases. Among the 640 CR+ve samples, 602 (94%) contained â„2 of 3 amyloid signature proteins (ASPs) on LDMS (ASP+ve) supporting the presence of amyloid. A total of 49 of the 60 CR-ve samples were ASPâve; 7 of 11 that were ASP+ve were glomerular. The amyloid fibril protein was identified by LDMS in 255 of 320 (80%) of the IHCâve samples and in a total of 545 of 640 (85%) cases overall. The LDMS and IHC techniques yielded discordant results in only 7 of 320 (2%) cases. CR histology and LDMS are corroborative for diagnosis of amyloid, but LDMS is superior to IHC for confirming amyloid type
Clinical ApoA-IV amyloid is associated with fibrillogenic signal sequence
Apolipoprotein A-IV amyloidosis is an uncommon form of the disease normally resulting in renal and cardiac dysfunction. ApoA-IV amyloidosis was identified in 16 patients attending the National Amyloidosis Centre and in eight clinical samples received for histology review. Unexpectedly, proteomics identified the presence of ApoA-IV signal sequence residues (p.18-43 to p.20-43) in 16/24 trypsin-digested amyloid deposits but in only 1/266 non-ApoA-IV amyloid samples examined. These additional signal residues were also detected in the cardiac sample from the Swedish patient in which ApoA-IV amyloid was first described, and in plasma from a single cardiac ApoA-IV amyloidosis patient. The most common signal-containing peptide observed in ApoA-IV amyloid, p.20-43, and to a far lesser extent the N-terminal peptide, p.21-43, were fibrillogenic in vitro at physiological pH, generating Congo red-positive fibrils. The addition of a single signal-derived alanine residue to the N-terminus has resulted in markedly increased fibrillogenesis. If this effect translates to the mature circulating protein in vivo, then the presence of signal may result in preferential deposition as amyloid, perhaps acting as seed for the main circulating native form of the protein; it may also influence other ApoA-IV-associated pathologies. \ua9 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland
cIMPACTâNOW update 7: advancing the molecular classification of ependymal tumors
Advances in our understanding of the biological basis and molecular characteristics of ependymal tumors since the latest iteration of the World Health Organization (WHO) classification of CNS tumors (2016) have prompted the cIMPACTâNOW group to recommend a new classification. Separation of ependymal tumors by anatomic site is an important principle of the new classification and was prompted by methylome profiling data to indicate that molecular groups of ependymal tumors in the posterior fossa and supratentorial and spinal compartments are distinct. Common recurrent genetic or epigenetic alterations found in tumors belonging to the main molecular groups have been used to define tumor types at intracranial sites; C11orf95 and YAP1 fusion genes for supratentorial tumors and two types of posterior fossa ependymoma defined by methylation group, PFA and PFB. A recently described type of aggressive spinal ependymoma with MYCN amplification has also been included. Myxopapillary ependymoma and subependymoma have been retained as histopathologically defined tumor types, but the classification has dropped the distinction between classic and anaplastic ependymoma. While the cIMPACTâNOW group considered that data to inform assignment of grade to molecularly defined ependymomas are insufficiently mature, it recommends assigning WHO grade 2 to myxopapillary ependymoma and allows grade 2 or grade 3 to be assigned to ependymomas not defined by molecular status.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162791/2/bpa12866_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162791/1/bpa12866.pd
Diagnosis, pathogenesis and outcome in leucocyte chemotactic factor 2 (ALECT2) amyloidosis
Introduction:
Renal biopsy series from North America suggest that leucocyte chemotactic factor 2 (ALECT2) amyloid is the third most common type of renal amyloid. We report the first case series from a European Centre of prevalence, clinical presentation and diagnostic findings in ALECT2 amyloidosis and report long-term patient and renal outcomes for the first time.
Methods:
We studied the clinical features, diagnostic investigations and the outcome of all patients with ALECT2 amyloidosis followed systematically at the UK National Amyloidosis Centre (NAC) between 1994 and 2015.
Results:
Twenty-four patients, all non-Caucasian, were diagnosed with ALECT2 amyloidosis representing 1.3% of all patients referred to the NAC with biopsy-proved renal amyloid. Diagnosis was made at median age of 62 years, usually from renal histology; immunohistochemical staining was definitive for ALECT2 fibril type. Median estimated glomerular filtration rate (GFR) at diagnosis was 33 mL/min/1.73 m2 and median proteinuria was 0.5 g/24 h. Hepatic amyloid was evident on serum amyloid P component (SAP) scintigraphy in 11/24 cases but was not associated with significant derangement of liver function. No patient had evidence of cardiac amyloidosis or amyloid neuropathy. Median follow-up was 4.8 (range 0.5â15.2) years, during which four patients died and four progressed to end-stage renal disease. The mean rate of GFR loss was 4.2 (range 0.5â9.6) mL/min/year and median estimated renal survival from diagnosis was 8.2 years. Serial SAP scans revealed little or no change in total body amyloid burden.
Conclusions:
ALECT2 amyloidosis is a relatively benign type of renal amyloid, associated with a slow GFR decline, which is reliably diagnosed on renal histology. Neither the molecular basis nor the factors underlying the apparent restriction of ALECT2 amyloidosis to non-Caucasian populations have been determined
Zero-field spin-splitting and spin lifetime in n-InSb/In1-xAlxSb asymmetric quantum well heterostructures
The spin-orbit (SO) coupling parameters for lowest conduction subband due to
structural (SIA) and bulk (BIA) inversion asymmetry are calculated for a range
of carrier densities in [001]-grown delta-doped n-type InSb/In1-xAlxSb
asymmetric quantum wells using the established 8 band k.p formalism [PRB 59,8
R5312 (1999)]. We present calculations for conditions of zero bias at 10 K. It
is shown that both the SIA and BIA parameters scale approximately linearly with
carrier density, and exhibit a marked dependence on well width when alloy
composition is adjusted to allow maximum upper barrier height for a given well
width. In contrast to other material systems the BIA contribution to spin
splitting is found to be of significant and comparable value to the SIA
mechanism in these structures. We calculate the spin lifetime for spins
oriented along [11-0] based on D'yakonov-Perel mechanism using both the theory
of Averkiev et al. [J. Phys.:Condens. Matter 14 (2002)] and also the rate of
precession of spins about the effective magnetic field, taking into account all
three SO couplings, showing good agreement.Spin lifeime for this direction is
largest in the narrow wells over the range of moderate carrier densities
considered, which is attributed to the reduced magnitude of the k-cubic BIA
parameter in narrow wells. The inherently large BIA induced SO coupling in
these systems is shown to have considerable effect on the spin lifetime, which
exhibits significant reduction in the maximum spin lifetime compared to
previous studies which consider systems with relatively weak BIA induced SO
coupling. The relaxation rate of spins oriented in the [001] direction is
dominated by the k-linear SIA and BIA coupling parameters and at least an order
of magnitude greater than in the [11-0] direction.Comment: 18 pages 12 figure
The experience of hereditary apolipoprotein A-I amyloidosis at the UK National Amyloidosis Centre
INTRODUCTION: Hereditary apolipoprotein A-I (AApoAI) amyloidosis is a rare heterogeneous disease with variable age of onset and organ involvement. There are few series detailing the natural history and outcomes of solid organ transplantation across a range of causative APOA1 gene mutations. METHODS: We identified all patients with AApoAI amyloidosis who presented to the National Amyloidosis Centre (NAC) between 1986 and 2019. RESULTS: In total, 57 patients with 14 different APOA1 mutations were identified including 18 patients who underwent renal transplantation (5 combined liver-kidney (LKT) and 2 combined heart-kidney (HKT) transplants). Median age of presentation was 43âyears and median time from presentation to referral was 3 (0-31âyears). Involvement of the kidneys, liver and heart by amyloid was detected in 81%, 67% and 28% of patients, respectively. Renal amyloidosis was universal in association with the most commonly identified variant (Gly26Arg, nâ=â28). Across all variants, patients with renal amyloidosis had a median creatinine of 159â”mol/L and median urinary protein of 0.3âg/24âh at the time of diagnosis of AApoAI amyloidosis and median time from diagnosis to end-stage renal disease was 15.0 (95% CI: 10.0-20.0) years. Post-renal transplantation, median allograft survival was 22.0 (13.0-31.0) years. There was one early death following transplantation (infection-related at 2âmonths post-renal transplant) and no episodes of early rejection leading to graft failure. Liver transplantation led to regression of amyloid in all four cases in whom serial 123I-SAP scintigraphy was performed. CONCLUSIONS: AApoAI amyloidosis is a slowly progressive disease that is challenging to diagnose. The outcomes of transplantation are encouraging and graft survival is excellent
What is food without love? The micro-politics of food practices in South Asians in Britain, India and Pakistan
This article draws on Morganâs theorisation of family life as consisting of political, moral, and emotional economies to examine the interplay of womenâs control over resources, gender norms, and expectations of intimacy in the context of household food consumption. The research that informs the article focuses on findings from 84 interviews with two South Asian groups: Pakistani Muslim and Gujarati Hindu women with at least one dependent child and from a variety of occupations and household compositions. In examining everyday food consumption, the research demonstrates how gender hierarchies are reproduced by parallel, mutually reinforcing, political, moral, and emotional economies. The women in the study sometimes struggled to subvert gender oppression and negotiate more powerful positions within the household through food management and/or employing manipulative and deceptive tactics. The article argues that, while access to economic resources is important if women are to achieve desirable food and nutritional outcomes, it is not in itself sufficient to meet this aim. Instead, the interplay of resources, gender norms, and conjugal relations are central to household food consumption
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