SEARCH · PubMed Health

Results for “AMYLOID”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources

PubMed1993

Morphological evaluation of amyloid-laden arteries in leptomeninges, cortices and subcortices in cerebral amyloid angiopathy with subcortical hemorrhage.

To investigate the relationship between cerebral amyloid angiopathy and subcortical (lobar) hemorrhage, we examined the severity of amyloid deposition in the leptomeningeal, cortical and subcortical arteries in 28 autopsied elderly patients with cerebral amyloid angiopathy with subcortical hemorrhage, deep cerebral hemorrhage or without hemorrhage. The severity was evaluated in terms of the frequency of amyloid-laden arteries and the degree of amyloid deposition within the arteries. The frequency of amyloid-laden arteries, especially among arteries over 200 microns in diameter, was higher in subcortical hemorrhage group than in the deep hemorrhage group and the non-hemorrhage group, and when the degree of amyloid deposition in the arteries was divided into four grades (none, mild, moderate or severe), the severity was higher in the subcortical hemorrhage group than in the deep cerebral hemorrhage group and the non-hemorrhage group. These results suggest that severe cerebral amyloid angiopathy is related to non-traumatic subcortical hemorrhage in elderly persons.

Aged↗

PubMed1992

Detection of autoantibodies against islet amyloid polypeptide in human serum. Lack of association with type 1 (insulin-dependent) diabetes mellitus, or with conditions favouring amyloid deposition in islets. The Belgian Diabetes Registry.

A radiobinding assay for the detection of autoantibodies against islet amyloid polypeptide was developed, analytically validated, and--in parallel with a similar assay for the detection of autoantibodies against insulin--applied to sera from recent-onset Type 1 (insulin-dependent) diabetic patients and from age- and sex-matched control subjects. There was no difference in islet amyloid polypeptide autoantibody titres between patient groups and matched control subjects, nor within subject groups according to age. At onset of Type 1 diabetes, elevated islet amyloid polypeptide-autoantibody levels (> 97th percentile of control subjects) were only detected in 1 of 30 patients aged 0-19 years and in 2 of 35 patients aged 20-39 years. By contrast, insulin autoantibodies were frequently demonstrated, in particular at onset of diabetes under age 20 (0-19 years: 18 of 30 patients; 20-39 years: 10 of 35 patients; p < 0.01 vs matched control subjects). Islet amyloid polypeptide autoantibodies were not detectable in 3 insulinoma patients nor in 37 patients (aged 33-70 years) with Type 2 diabetes (vs 1 of 40 in matched control subjects). In positive serum, adsorption onto protein A-Sepharose removed islet amyloid polypeptide binding activity, hereby confirming its antibody nature. In conclusion, Type 1 diabetes is associated with an age-dependent autoantibody reaction against insulin but not against islet amyloid polypeptide. Conditions associated with amyloid deposition in islets (Type 2 diabetes, insulinoma and ageing) do not favour the formation of autoantibodies against islet amyloid polypeptide.

Adolescent↗

PubMed1999

Cytoskeletal pathology in familial cerebral amyloid angiopathy (British type) with non-neuritic amyloid plaque formation.

The histological features of familial cerebral amyloid angiopathy (British type) with non-neuritic amyloid plaque formation (FAB) include deposition of amyloid, (supposedly associated with the C-terminal fragments of both alpha- and beta-tubulin), in small cerebral and spinal arteries, hippocampal amyloid plaques and neurofibrillary tangles (NFTs) as well as ischaemic white matter changes. In the present study we report on the cytoskeletal pathology that occurs in association with FAB. Sections from the hippocampus and cerebellum of three cases from three unrelated families were stained with silver impregnation methods and antibodies to antigens including tau, neurofilaments, ubiquitin and glial fibrillary acidic protein. Electron microscopic examination of the hippocampus was carried out in one case. All hippocampal subregions contained large numbers of NFTs and neuropil threads (NT), which were stained with both phosphorylation-dependent and phosphorylation-independent tau antibodies and ultrastructurally were found to be composed of paired helical filaments (PHFs). Although the majority of the amyloid plaques were of the non-neuritic type, distended PHF-containing and tau-positive neurites were seen in close proximity of a minority of the hippocampal plaques. The perivascular amyloid deposits of the cerebellum contained numerous ubiquitin-positive granular elements similar to those seen in cerebellar A beta amyloid plaques in Alzheimer's disease. In FAB severe cytoskeletal pathology is present in areas most affected by amyloid plaque deposits, thus suggesting a localised neurotoxic effect of the poorly characterised amyloidogenic peptide characteristic of this condition.

Biomarkers↗

PubMed2001

Expression and distribution of beta amyloid precursor protein and beta amyloid peptide in reactive astrocytes after transient middle cerebral artery occlusion.

BACKGROUND: In the brains of Alzheimer's disease patients, beta amyloid protein is the major component of senile plaque. In ischemic stress, beta amyloid precursor protein (APP) and beta amyloid peptide are reported to be upregulated. METHOD: Using Male Wistar-ST rats, expression and distribution of APP and beta amyloid peptide were examined immunohistochemically after transient ischemia induced by a 2-h middle cerebral artery occlusion (MCAO). After reperfusion for 3, 7, 14, 30 and 60 days, brains were removed and immunostaining was performed. FINDINGS: The reactive astrocytes with APP were observed in the periphery of infarct from 3 days to 60 days post-occlusion. The immunoreactivity of beta amyloid peptide was also localized in the reactive astrocytes in the peripheral zone of infarct at 7, 14, and 30 days post-occlusion. However, beta amyloid expression was not identified at 3 days or 60 days post MCAO. Transient ischemia temporarily induced beta amyloid peptide expression in reactive astrocytes, but this expression peaked at 30 days and disappeared at 60 days. INTERPRETATION: These findings suggested that beta amyloid peptide was derived from the processing of APP produced in the same reactive astrocytes and the production of the peptide stopped within 60 days after the ischemic stress.

Alzheimer Disease↗

PubMed1990

Formation of amyloid-like fibrils in COS cells overexpressing part of the Alzheimer amyloid protein precursor.

A pathological hallmark of Alzheimer's disease is the deposition of amyloid fibrils in the brain. The principal component of the amyloid fibril is beta/A4 protein, which is derived from a large membrane-bound glycoprotein, Alzheimer amyloid protein precursor (APP). Although the deposition of amyloid is thought to result from the aberrant processing of APP, the detailed molecular mechanisms of amyloidogenesis remain unclear. A C-terminal fragment of APP which spans the beta/A4 and cytoplasmic domains has a tendency to self-aggregate. In an attempt to establish a cultured-cell model for amyloid fibril formation, we have transfected COS-1 cells with complementary DNA encoding the C-terminal 100 residues of APP. In the perinuclear regions of a small population of DNA-transfected cells, we observed inclusion-like deposits which showed a strong immunohistochemical reaction towards an anti-C-terminal APP antibody or an anti-beta/A4 amyloid core-specific antibody. Electron microscope observations of the inclusion-carrying cells revealed an accumulation of amyloid-like fibrils of 8-22 nm diameter near and on the nuclear membrane. The fibrils showed a beaded or helical structure, and reacted positively with the anti-C-terminus antibody by immunoelectron microscopy. These results suggest that the formation of amyloid fibrils is an inherent characteristic of the C-terminal peptide of APP. The present system provides a suitable model for the molecular dissection of the process of brain amyloidogenesis.

Alzheimer Disease↗

PubMed1999

Neuronal overexpression of mutant amyloid precursor protein results in prominent deposition of cerebrovascular amyloid.

Transgenic mice that overexpress mutant human amyloid precursor protein (APP) exhibit one hallmark of Alzheimer's disease pathology, namely the extracellular deposition of amyloid plaques. Here, we describe significant deposition of amyloid beta (Abeta) in the cerebral vasculature [cerebral amyloid angiopathy (CAA)] in aging APP23 mice that had striking similarities to that observed in human aging and Alzheimer's disease. Amyloid deposition occurred preferentially in arterioles and capillaries and within individual vessels showed a wide heterogeneity (ranging from a thin ring of amyloid in the vessel wall to large plaque-like extrusions into the neuropil). CAA was associated with local neuron loss, synaptic abnormalities, microglial activation, and microhemorrhage. Although several factors may contribute to CAA in humans, the neuronal origin of transgenic APP, high levels of Abeta in cerebrospinal fluid, and regional localization of CAA in APP23 mice suggest transport and drainage pathways rather than local production or blood uptake of Abeta as a primary mechanism underlying cerebrovascular amyloid formation. APP23 mice on an App-null background developed a similar degree of both plaques and CAA, providing further evidence that a neuronal source of APP/Abeta is sufficient to induce cerebrovascular amyloid and associated neurodegeneration.

Aging↗

PubMed2004

Non-fibrillar components of amyloid deposits mediate the self-association and tangling of amyloid fibrils.

Amyloid deposits are proteinaceous extra-cellular aggregates associated with a diverse range of disease states. These deposits are composed predominantly of amyloid fibrils, the unbranched, beta-sheet rich structures that result from the misfolding and subsequent aggregation of many proteins. In addition, amyloid deposits contain a number of non-fibrillar components that interact with amyloid fibrils and are incorporated into the deposits in their native folded state. The influence of a number of the non-fibrillar components in amyloid-related diseases is well established; however, the mechanisms underlying these effects are poorly understood. Here we describe the effect of two of the most important non-fibrillar components, serum amyloid P component and apolipoprotein E, upon the solution behavior of amyloid fibrils in an in vitro model system. Using analytical ultracentrifugation, electron microscopy, and rheological measurements, we demonstrate that these non-fibrillar components cause soluble fibrils to condense into localized fibrillar aggregates with a greatly enhanced local density of fibril entanglements. These results suggest a possible mechanism for the observed role of non-fibrillar components as mediators of amyloid deposition and deposit stability.

Amyloid↗

PubMed1999

Ischemic rats as a model in the study of the neurobiological role of human beta-amyloid peptide. Time-dependent disappearing diffuse amyloid plaques in brain.

Brains from patients with Alzheimer's disease contain diffuse and senile amyloid plaques. Using an experimental model, we have addressed the issue whether diffuse plaques of amyloid persist, develop with time, or both, in rats injected with human beta-amyloid-(1-42)-peptide for 3 and 12 mon after brain ischemia. Rats receiving beta-amyloid peptide for 3 months after brain ischemia demonstrated widespread diffuse amyloid plaques in hippocampus and cerebral cortex. Neuronal, glial, ependymal, endothelial and pericyte cell bodies were observed filled with beta-amyloid peptide. No staining was observed in control brains. In the group alive 1 year no deposition of human beta-amyloid peptide was observed, too. Direct evidence that diffuse amyloid plaques can disappear in the brain is thus provided for the first time.

Alzheimer Disease↗

PubMed1994

AA glomerular amyloid. An ultrastructural immunogold study of the colocalization of heparan sulphate proteoglycan and P component with amyloid fibrils together with changes in distribution of type IV collagen and fibronectin.

An ultrastructural investigation was undertaken on paraformaldehyde-fixed Lowicryl resin-embedded human kidneys of three patients with AA amyloidosis to investigate the association of various basement membrane components with amyloid fibrils. An immunogold technique was used and antibodies to serum amyloid A, heparan sulphate proteoglycan, type IV collagen, P component, and fibronectin were applied to human normal and amyloid glomeruli. The amyloid was identified as AA, and P component was shown to be intimately associated with the fibrils. In addition, heparan sulphate proteoglycan was associated with amyloid in all subendothelial, subepithelial and intramembranous glomerular basement membrane deposits, and those throughout the mesangial matrix. This contrasted with the distribution of the proteoglycan in the normal glomerulus where it was found predominantly on the epithelial aspect of the basement membrane and only in the more peripheral regions of the mesangium. The accumulation of heparan sulphate proteoglycan with amyloid resulted in a marked increase in its amount in the glomeruli. The amyloid deposits contained little or no type IV collagen or fibronectin. These findings demonstrate a strong association of heparan sulphate proteoglycan with amyloid and suggest different roles for the various glomerular basement membrane components in amyloidogenesis.

Amyloidosis↗

PubMed1999

Two novel immortal pancreatic beta-cell lines expressing and secreting human islet amyloid polypeptide do not spontaneously develop islet amyloid.

Type 2 diabetes is characterized by islet amyloid deposits, which are primarily composed of the amyloidogenic human form of islet amyloid polypeptide (IAPP, amylin). The mechanism of islet amyloido-genesis is not known, but other products (e.g., apolipoprotein E and perlecan) contained within islet amyloid may be necessary. Because rodent IAPP does not form islet amyloid, the currently available beta-cell lines are not useful for studying processes involved in amyloid formation. To develop a suitable in vitro cell system for the study of islet amyloid formation, we generated two new beta-cell lines that express the amyloidogenic human IAPP. We did this by crossbreeding human IAPP transgenic mice with RIP-Tag mice that develop islet tumors and then culturing one of these islet tumors from two separate offspring of this cross. The resultant 2350-2C0 and 2511 cell lines produce human as well as mouse IAPP-like immunoreactivity (IAPP-LI) and immunoreactive insulin (IRI). Incubation of both these cell lines with 16.7 mmol/l glucose resulted in a two- to fourfold increase in human IAPP-LI, mouse IAPP-LI, and IRI secretion compared with 1.67 mmol/l glucose and the combination of 16.7 mmol/l glucose and 10 mmol/l arginine, 0.1 mmol/l 3-isobutyl-1-methylxanthine (IBMX), and 5 micromol/l carbachol induced a >50-fold increase in the release of these peptides. The omission of calcium from the above secretagogue cocktail reduced secretion of all three peptides to only two- to sixfold higher than the 16.7 mmol/l glucose condition. Perifusion with 16.7 mmol/l glucose plus 0.1 mmol/l IBMX caused a biphasic secretion of human IAPP-LI and mouse IAPP-LI, as well as IRI, in both cell lines, with the peak of the first phase being five- to sixfold higher than the prestimulated 1.67 mmol/l glucose condition. Immunoelectron microscopic inspection of both 2350-2C0 and 2511 cells after 7 days of culture did not reveal the presence of amyloid fibrils, suggesting the need for other critical components. We conclude that we have established two novel beta-cell lines that produce and secrete human IAPP in a regulated manner. These cell lines will be a useful tool to investigate the secretion of human IAPP as well as the necessity of other components for islet amyloid formation.

Amyloid↗

PubMed2001

Homozygous serum amyloid P component-deficiency does not enhance regression of AA amyloid deposits.

Serum amyloid P component (SAP) is a common protein constituent of all types of amyloid deposits. Using SAP-deficient mice generated through gene targeting, we and others have shown that SAP significantly promotes amyloid deposition. It has been speculated that SAP protects amyloid fibrils from degradation by coating their exterior surface. To assess potential ways of treating individuals with amyloidosis, we examined the persistence of splenic AA amyloid fibrils in SAP-deficient and wild-type mice. No enhancement in the rate of regression of splenic AA amyloid was observed in the SAP-deficient mice relative to wild-type mice. These results present, for the first time, evidence that lack of SAP in AA amyloid deposits does not enhance regression of the deposits in vivo and suggest that dissociation of bound SAP from AA amyloid deposits would not significantly accelerate regression of the deposits in vivo.

Amyloidosis↗

PubMed2002

Effects of free fatty acid on polymerization of islet amyloid polypeptide (IAPP) in vitro and on amyloid fibril formation in cultivated isolated islets of transgenic mice overexpressing human IAPP.

BACKGROUND: Islet amyloid polypeptide (IAPP) is deposited as amyloid in the islets of Langerhans in type 2 diabetes. The mechanism behind the formation of the cytotoxic fibrils is unknown. Islet amyloid develops in a mouse IAPP null mouse strain that expresses human IAPP (+hIAPP/-mIAPP) after 9 months on a high-fat diet. Herein we investigate the effect that individual free fatty acids (FFAs) exert on formation of amyloid-like fibrils from synthetic IAPP and the effects of FFAs on IAPP polymerization in +hIAPP/-mIAPP islets cultivated in vitro. MATERIALS AND METHODS: In the study myristic acid, palmitic acid, stearic acid, oleic acid, and linoleic acid were used together with albumin. Thioflavin T (Th T) assay was used for quantification of amyloid-like fibrils. Islets were isolated from the +hIAPP/-mIAPP transgenic strain and cultured in the presence of the FFAs for 2 days. Immuno-electron microscopy was used for evaluation. RESULTS: The Th T assay showed that all studied FFAs potentiated fibril formation but that myristic acid revealed the highest capacity. In some cells from cultured islets, intragranular aggregates were present. These aggregates had a filamentous appearance and labeled with antibodies against IAPP. In some cells cultured in the presence of linoleic acid, large amounts of intracellular amyloid were present. Earlier, this has not been observed after such a short incubation period. CONCLUSIONS: Our studies suggest that FFAs can potentiate amyloid formation in vitro, probably without being integrated in the fibril. Cultivation of +hIAPP/-mIAPP transgenic mouse islets with FFAs results in altered morphology of the secretory granules with appearance of IAPP- immunoreactive fibrillar material. We suggest that such fibrillar material may seed extracellular amyloid formation after exocytosis.

Amyloid↗

PubMed1987

Brain amyloid in normal aging and cerebral amyloid angiopathy is antigenically related to Alzheimer's disease beta-protein.

Amyloid deposition is a prominent feature of a number of brain disorders, in which amyloid fibrils are found within blood vessel walls, the neuropil (neuritic plaques), neurons (neurofibrillary tangles). These include Alzheimer's disease (AD), AD changes associated with Down's syndrome, neurologically asymptomatic amyloidosis, Parkinson dementia of Guam, hereditary cerebral hemorrhage with amyloidosis of Icelandic origin (HCHWA-I), hereditary cerebral hemorrhage with amyloidosis of Dutch origin (HCHWA-D), and sporadic cerebral amyloid angiopathy (SCAA). Recently it was shown that the amyloid deposits in AD, Parkinson dementia of Guam, and HCHWA-D are formed by a similar 4-kd polypeptide called beta-protein. Because the nature of the amyloid deposits in other types of cerebral amyloidosis is not known, we have conducted immunocytochemical studies on brains from autopsy cases of AD, HCHWA-D, SCAA and neurologically asymptomatic elderly individuals. Brains from two subjects without neurologic involvement were used as controls. Sections from these specimens were incubated with rabbit polyclonal antibodies against 1) a synthetic peptide of 28 residues (anti-SP28), homologous to the NH2-terminal sequence of the beta-protein, 2) the main amyloid component of the HCHWA-I, a variant of cystatin C, and 3) purified fraction of neurofibrillary tangles. In all cases, anti-SP28 antibody specifically stained amyloid deposits in leptomeningeal and cortical vessels and neuritic plaques. These findings demonstrate that the amyloid deposits of SCAA and aged brains are composed of a protein antigenically similar to AD, HCHWA-D, and Parkinson dementia of Guam beta-protein, suggesting that all of these clinically and etiologically different morbid conditions are pathogenetically related. On this basis, they can be tentatively grouped as beta-protein deposition diseases. In addition, we found that HCHWA-D and SCAA vessels were mainly affected, while in AD parenchymal involvement predominates. These differences in the localization and extent of beta-protein deposits may account from the predominance of vascular complications in HCHWA-D and SCAA and of dementia in AD.

Aging↗

PubMedDate not supplied

Colocalization of different types of amyloid in the walls of cerebral blood vessels of patients suffering from cerebral amyloid angiopathy and spontaneous intracranial hemorrhage: a report of 5 cases.

Four cases of spontaneous intracranial hemorrhage (ICH) are described in which the diagnosis of a cerebral amyloid angiopathy (CAA) was made in the biopsy specimens. In one further case CAA was detected on autopsy after intracranial hemorrhage (ICH). Amyloidotic degeneration of the vessel walls appeared to be the most likely reason for the ICH which in these cases especially involved superficial neocortical regions. In all cases, co-deposition of A4beta-amyloid and ALlambda-amyloid was found in diseased leptomeningeal and cortical vessels. Besides CAA, all 5 patients suffered from other diseases which had affected the blood vessel walls such as atherosclerosis, diabetes mellitus or arterial hypertension. However, no signs of systemic amyloidosis could be detected in these cases. It is suggested that the observed co-deposition of 2 amyloid subtypes is based on the combination of 2 different diseases, one of which results in a local production of A4beta-amyloid in the tunica media of cerebral blood vessels and another one, e.g. arterial hypertension, which impairs the permeability of the blood vessels by affection of the tunica intima allowing for the pathological penetration of circulating immunoglobulin lambda-light chains into the vessel wall. Subsequently, the preexisting A4beta-amyloid might have induced the polymerization of the lambda-light chains to ALlambda-amyloid in the media of the vessels and could have aggravated the amyloidotic degeneration of the vessel walls.

Adult↗

PubMed1996

Ultrastructural immunolabelling of amyloid fibrils in acquired and hereditary amyloid neuropathies.

Both acquired and familial amyloid neuropathies carry a poor prognosis. In addition, amyloid is sometimes difficult to visualise in nerve biopsy specimens, and the pathogenesis of nerve lesions is still a matter of controversy. In order to learn more on the subject, we studied nerve specimens from seven patients with proven amyloid neuropathy by ultrastructural immunocytochemistry in order to better understand their pathogeny and to evaluate the reliability of the method for detection of amyloid antigens in the endoneurium. An indirect immunolabelling technique using protein A-gold complex (pA-g) was applied. Polyclonal antisera against human IgG, IgM, lambda and kappa light chains and prealbumin were assayed. Amyloid fibrils were labelled in six of seven cases: in four cases with anti-transthyretin (TTR) antibodies and in two with anti-lambda light chain antibodies. The type of immunolabelling correlated with the biochemical type of the amyloidosis as defined by TTR gene analysis and serum immunoelectrophoresis. The amyloid fibrils and gold labelling were always located in the endoneurial space. No intracellular deposit or labelling was found. The immunolabelling was highly specific, gold particles being detected only near to amyloid fibrils with no background gold labelling. Ultrastructural immunolabelling with pA-g could be used for detection of amyloid in progressive axonal neuropathy of unknown origin, with important therapeutic implications.

Adult↗

PubMed1990

Amyloid in intervertebral discs of surgery and autopsy material. A new class of amyloid?

Intervertebral discs from 82 consecutive operations on herniation and 59 autopsies (one case with generalized amyloidosis) were studied. Amyloid deposits observed in surgical and autopsy specimens increased with age in both series. Degenerative changes were related to age and to amyloid deposits in autopsy, but not in surgical cases. Calcium pyrophosphate dihydrate deposits (often in proximity to amyloid deposits) were found in autopsy discs of six patients and in surgical specimens of three patients with previous operations on herniated discs. Antisera against amyloid fibril proteins of different types including AA-, A lambda-, A kappa, AF- and AB-types showed no reaction with disc amyloid. In one case with generalized A lambda-amyloidosis the disc amyloid was not of the A lambda-type. Based on our results, we suppose that disc amyloid is a form of localized senile amyloidosis - possibly representing a new class of amyloid limited to cartilage tissue.

Adult↗

PubMed1986

The induction of accelerated murine amyloid with human splenic extract. Probable role of amyloid enhancing factor.

Amyloid enhancing factor (AEF) is derived from the tissues of pre-amyloidotic and amyloidotic animals and, when transferred, greatly accelerates amyloid induction in the recipient murine models. It has also been reported that similarly accelerated amyloid induction can be achieved in mice by injection of human splenic homogenates from patients with amyloidosis. The present study has attempted to characterize further the mechanism of this "heterologous transfer of amyloid". Treatment of mice with the "tissue homogenate" or the "AEF extract" of AA-, AL- and A prealbumin-laden human spleens followed by daily subcutaneous casein injections induced amyloidosis in an accelerated fashion. The resultant amyloid deposits in mice had strongly positive immunohistochemical reactions with anti-mouse AA, and negative reaction with anti-human AA or anti-human prealbumin. The results lend support to the idea that accelerated amyloid induction in the recipient mice is unlikely to be due to transfer of human amyloid substance, but rather to formation of "native" murine amyloid under the influence of a human AEF factor similar to or identical with AEF described in mouse-to mouse transfer models.

Amyloid↗

PubMed1990

Amyloid elastosis: analysis of the role of amyloid P component.

We report the second case of amyloid elastosis. Our patient had an underlying primary systemic amyloidosis with lambda light chain paraproteinemia. Salient clinical features included a sclerodermatous facial appearance, cordlike thickening of superficial blood vessels, neck skin resembling that in pseudoxanthoma elasticum, livedo reticularis-like changes on the trunk, Raynaud's phenomenon, arterial and venous thromboses, and the nephrotic syndrome. Amyloid deposits were present in the dermis, around appendages, in blood vessel walls, and in a striking distribution surrounding individual elastic fibers, that appeared shortened and fragmented. Immunofluorescence, electron microscopic, and immunoultrastructural studies with antibodies to lambda light chain, localized the amyloid deposits to the region of the elastic fiber microfibrils, with which amyloid P component (AP) is invariably associated in normal tissues. Because AP binds amyloid fibrils, codistribution of amyloid deposits and AP in amyloid elastosis strongly supports the theory that elastic fiber-associated AP may act as a nidus for amyloid deposition.

Amyloidosis↗