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Diabetes Mellitus, Obesity, Lipoprotein Disorders and other Metabolic Diseases
Published in John S. Axford, Chris A. O'Callaghan, Medicine for Finals and Beyond, 2023
When stained with Congo red dye amyloid fibrils show red-green birefringence under polarized light in tissue biopsy histochemistry samples. The type of amyloid fibril is determined by immunohistochemical staining using specific antibodies. Measurement of serum free light chains may point to a diagnosis of amyloidosis. Radiolabelled SAP is used as a nuclear medicine tracer for imaging of amyloid deposits in vivo to provide a whole-body survey and for serial monitoring (Figure 11.25).
Inherited Abnormalities in Thyroid Hormone Transport Proteins
Published in Geraldo Medeiros-Neto, John Bruton Stanbury, Inherited Disorders of the Thyroid System, 2019
Geraldo Medeiros-Neto, John Bruton Stanbury
The variant TTR called type I, associated with FAP, is characterized by the replacement of valine at position 30 by methionine. It is not only present in the amyloid fibril protein but also in the serum of affected individuals. The variant TTR has a reduced affinity for T4. The so-called Indiana variant or type II has a serine for isoleucine replacement at position 84. Types ΠΙ and IV, have other mutations, as shown in Tables 2 and 3. Genetic abnormalities of TTR can be accompanied by altered affinity for T4but the thyroid status of the affected person is normal. Three other mutant TTRs have been identified recently either anoliated with FAP50a,50bor familial amyloid cardiomyopathy.50c
Measurement of Brain Age: Conceptual Issues and Neurobiological Indices
Published in Richard C. Adelman, George S. Roth, Endocrine and Neuroendocrine Mechanisms of Aging, 2017
Congophilic senile plaques have been observed for many years in autopsied brains of elderly humans, particularly in those with senile dementia. In recent years, however, the application of electron microscopic (EM) techniques to brain material from humans, monkeys, and dogs has substantially clarified the underlying nature of these plaques.17,42 It is now clear that these plaques are primarily comprised of clusters of degenerating synaptic terminals and dendritic spines, and are surrounded by reactive glial elements. In later stages, extracellular amyloid fibrils are prominent. The degeneration of the synaptic elements appears to be the initial step in plaque development.45 Plaques have been reported in humans, monkeys, and dogs, and are most common in neocortex and hippocampus.17,43 While found in normal elderly humans, the density of plaques is greatly increased in senile dements.43
Incidence rate of hospitalization and mortality in the first year following initial diagnosis of cardiac amyloidosis in the US claims databases
Published in Current Medical Research and Opinion, 2021
Lu Wang, Joel N. Swerdel, James Weaver, Brendan Weiss, Guohua Pan, Zhong Yuan, Peter M. DiBattiste
Amyloidosis is a group of rare diseases in which amyloid fibrils, composed of low-molecular-weight subunits (5–25 kD) of unrelated proteins, build up in extracellular tissue1. The pathophysiology involves the mis-folding of native proteins resulting from excess production, cleavage, or denaturation of precursor proteins, which eventually form insoluble amyloid fibrils2,3 and disrupt the structure and function of involved organs and tissues4. Systemic amyloidosis are classified into subtypes based on precursor proteins that form the fibril deposits: immunoglobulin light chain amyloidosis (AL), secondary amyloidosis (AA), transthyretin amyloidosis (ATTR) which is divided into a mutant or variant-type (ATTRm) and a wild-type (ATTRwt), and dialysis-related amyloidosis (Aβ2M)5, are among the most common. The prognosis of amyloidosis is generally poor, but varies by the amount of amyloidogenic protein and the extent and the number of organs involved6. Different subtypes of amyloidosis tend to have different natural history. Of the major subtypes, AL and ATTR commonly involve the heart, and the prognoses are worse than other subtypes7.
Emerging role of metabolomics in protein conformational disorders
Published in Expert Review of Proteomics, 2021
Nimisha Gupta, Sreelakshmi Ramakrishnan, Saima Wajid
Cells prevent the formation of toxic aggregates resulting from protein misfolding by degrading misfolded proteins with the help of cellular proteasomes [30]. Undegraded protein aggregates may cause various diseases, including neurodegenerative diseases and systemic amyloidosis [8]. The conformational changes in the protein structure and misfolding take place due to genetic mutations, translational errors, abnormal protein modification, thermal and oxidative stress, leading to insoluble complex formation [10]. However, the fundamental reasons for the development and prevention of these diseases are not well understood and are becoming a major concern for health management. Amyloid fibrils are aggregates of proteins deposited in different cells, tissues, and organs, resulting in the malfunctioning of the organs, such as the kidney, heart, liver, and brain [9]. Organ dysfunction leads to Alzheimer’s, Parkinson’s, Huntington’s, prion disease, systemic amyloidoses such as renal amyloidosis, cardiac amyloidosis, AL amyloidosis, AA amyloidosis, and many others [12].
Fibrinogen alpha amyloidosis: insights from proteomics
Published in Expert Review of Proteomics, 2019
Amyloidoses are a group of diseases that result from the systemic or localized deposition of amyloid fibrils in the extra-cellular spaces of tissues causing organ dysfunction and potentially death. These diseases can affect any organ and are often underdiagnosed. Amyloid fibrils are insoluble protein aggregates that form when a protein becomes misfolded. There are 36 biochemically diverse proteins that are accepted to cause amyloidosis, but the common feature of these proteins is the propensity to form beta-pleated sheets under appropriate conditions (Table 1) [20]. The beta-pleated sheets align in an antiparallel fashion and through hydrogen bond interactions form long protofilaments. Protofilaments interact via their side chains to form fibrils [21]. These rigid fibrils resist proteolysis in the affected tissues and organs [22,23].