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Background: Wild‐type transthyretin (ATTRwt) amyloidosis is the most common systemic amyloidosis in Western countries and manifests mainly as progressive restrictive cardiomyopathy. Objective: To study the prevalence of ATTR deposits in ligament tissue in patients undergoing surgery for lumbar spinal stenosis and to assess whether these deposits are associated with cardiac amyloidosis. Materials and methods: A total of 250 patients, aged 50–89 (57% women), none with known cardiovascular disease, were included. Ligaments were investigated microscopically for amyloid. ATTR type was determined by immunohistochemistry and fibril type by Western blot. The amount of amyloid was graded 0‐4. All patients with grade 3‐4 ATTR deposits were offered cardiac investigation including ECG, cardiac ultrasound, plasma NT‐proBNP and cardiac magnetic resonance (CMR), including modern tissue characterization. Results: Amyloid was identified in 221 of the samples (88.4%). ATTR appeared in 93 samples (37%) of whom 42 (17 women and 25 men) were graded 3‐4; all had fibril type A (mixture of full‐length TTR and fragmented TTR). Twenty‐nine of 42 patients with grade 3‐4 ATTR deposits accepted cardiovascular investigations; none of them had definite signs of cardiac amyloidosis, but five men had a history of carpal tunnel syndrome. Conclusions: The prevalence of ATTR deposits in ligamentum flavum in patients with lumbar spinal stenosis was high but not associated with manifest ATTR cardiac amyloidosis. However, the findings of fibril type A, the prevalence of previous carpal tunnel syndrome and ATTR amyloid in surrounding adipose and vascular tissue indicate that amyloid deposits in ligamentum flavum may be an early manifestation of systemic ATTR disease.

Background: Wild‐type transthyretin (ATTRwt) amyloidosis is the most common systemic amyloidosis in Western countries and manifests mainly as progressive restrictive cardiomyopathy. Objective: To study the prevalence of ATTR deposits in ligament tissue in patients undergoing surgery for lumbar spinal stenosis and to assess whether these deposits are associated with cardiac amyloidosis. Materials and methods: A total of 250 patients, aged 50–89 (57% women), none with known cardiovascular disease, were included. Ligaments were investigated microscopically for amyloid. ATTR type was determined by immunohistochemistry and fibril type by Western blot. The amount of amyloid was graded 0‐4. All patients with grade 3‐4 ATTR deposits were offered cardiac investigation including ECG, cardiac ultrasound, plasma NT‐proBNP and cardiac magnetic resonance (CMR), including modern tissue characterization. Results: Amyloid was identified in 221 of the samples (88.4%). ATTR appeared in 93 samples (37%) of whom 42 (17 women and 25 men) were graded 3‐4; all had fibril type A (mixture of full‐length TTR and fragmented TTR). Twenty‐nine of 42 patients with grade 3‐4 ATTR deposits accepted cardiovascular investigations; none of them had definite signs of cardiac amyloidosis, but five men had a history of carpal tunnel syndrome. Conclusions: The prevalence of ATTR deposits in ligamentum flavum in patients with lumbar spinal stenosis was high but not associated with manifest ATTR cardiac amyloidosis. However, the findings of fibril type A, the prevalence of previous carpal tunnel syndrome and ATTR amyloid in surrounding adipose and vascular tissue indicate that amyloid deposits in ligamentum flavum may be an early manifestation of systemic ATTR disease.

Background: Wild‐type transthyretin (ATTRwt) amyloidosis is the most common systemic amyloidosis in Western countries and manifests mainly as progressive restrictive cardiomyopathy. Objective: To study the prevalence of ATTR deposits in ligament tissue in patients undergoing surgery for lumbar spinal stenosis and to assess whether these deposits are associated with cardiac amyloidosis. Materials and methods: A total of 250 patients, aged 50–89 (57% women), none with known cardiovascular disease, were included. Ligaments were investigated microscopically for amyloid. ATTR type was determined by immunohistochemistry and fibril type by Western blot. The amount of amyloid was graded 0‐4. All patients with grade 3‐4 ATTR deposits were offered cardiac investigation including ECG, cardiac ultrasound, plasma NT‐proBNP and cardiac magnetic resonance (CMR), including modern tissue characterization. Results: Amyloid was identified in 221 of the samples (88.4%). ATTR appeared in 93 samples (37%) of whom 42 (17 women and 25 men) were graded 3‐4; all had fibril type A (mixture of full‐length TTR and fragmented TTR). Twenty‐nine of 42 patients with grade 3‐4 ATTR deposits accepted cardiovascular investigations; none of them had definite signs of cardiac amyloidosis, but five men had a history of carpal tunnel syndrome. Conclusions: The prevalence of ATTR deposits in ligamentum flavum in patients with lumbar spinal stenosis was high but not associated with manifest ATTR cardiac amyloidosis. However, the findings of fibril type A, the prevalence of previous carpal tunnel syndrome and ATTR amyloid in surrounding adipose and vascular tissue indicate that amyloid deposits in ligamentum flavum may be an early manifestation of systemic ATTR disease.

Background: Wild‐type transthyretin (ATTRwt) amyloidosis is the most common systemic amyloidosis in Western countries and manifests mainly as progressive restrictive cardiomyopathy. Objective: To study the prevalence of ATTR deposits in ligament tissue in patients undergoing surgery for lumbar spinal stenosis and to assess whether these deposits are associated with cardiac amyloidosis. Materials and methods: A total of 250 patients, aged 50–89 (57% women), none with known cardiovascular disease, were included. Ligaments were investigated microscopically for amyloid. ATTR type was determined by immunohistochemistry and fibril type by Western blot. The amount of amyloid was graded 0‐4. All patients with grade 3‐4 ATTR deposits were offered cardiac investigation including ECG, cardiac ultrasound, plasma NT‐proBNP and cardiac magnetic resonance (CMR), including modern tissue characterization. Results: Amyloid was identified in 221 of the samples (88.4%). ATTR appeared in 93 samples (37%) of whom 42 (17 women and 25 men) were graded 3‐4; all had fibril type A (mixture of full‐length TTR and fragmented TTR). Twenty‐nine of 42 patients with grade 3‐4 ATTR deposits accepted cardiovascular investigations; none of them had definite signs of cardiac amyloidosis, but five men had a history of carpal tunnel syndrome. Conclusions: The prevalence of ATTR deposits in ligamentum flavum in patients with lumbar spinal stenosis was high but not associated with manifest ATTR cardiac amyloidosis. However, the findings of fibril type A, the prevalence of previous carpal tunnel syndrome and ATTR amyloid in surrounding adipose and vascular tissue indicate that amyloid deposits in ligamentum flavum may be an early manifestation of systemic ATTR disease.

Background: Wild‐type transthyretin (ATTRwt) amyloidosis is the most common systemic amyloidosis in Western countries and manifests mainly as progressive restrictive cardiomyopathy. Objective: To study the prevalence of ATTR deposits in ligament tissue in patients undergoing surgery for lumbar spinal stenosis and to assess whether these deposits are associated with cardiac amyloidosis. Materials and methods: A total of 250 patients, aged 50–89 (57% women), none with known cardiovascular disease, were included. Ligaments were investigated microscopically for amyloid. ATTR type was determined by immunohistochemistry and fibril type by Western blot. The amount of amyloid was graded 0‐4. All patients with grade 3‐4 ATTR deposits were offered cardiac investigation including ECG, cardiac ultrasound, plasma NT‐proBNP and cardiac magnetic resonance (CMR), including modern tissue characterization. Results: Amyloid was identified in 221 of the samples (88.4%). ATTR appeared in 93 samples (37%) of whom 42 (17 women and 25 men) were graded 3‐4; all had fibril type A (mixture of full‐length TTR and fragmented TTR). Twenty‐nine of 42 patients with grade 3‐4 ATTR deposits accepted cardiovascular investigations; none of them had definite signs of cardiac amyloidosis, but five men had a history of carpal tunnel syndrome. Conclusions: The prevalence of ATTR deposits in ligamentum flavum in patients with lumbar spinal stenosis was high but not associated with manifest ATTR cardiac amyloidosis. However, the findings of fibril type A, the prevalence of previous carpal tunnel syndrome and ATTR amyloid in surrounding adipose and vascular tissue indicate that amyloid deposits in ligamentum flavum may be an early manifestation of systemic ATTR disease.

Although hereditary transthyretin (h-ATTR) amyloidosis is a monogenetic disease, a large variation in its phenotype has been observed. The common hypothesis of amyloid fibril formation involves dissociation of the transthyretin (TTR) tetramer into monomers that after misfolding reassemble into amyloid fibrils. This notion is partly challenged by the finding of two distinct types of amyloid fibrils. One of these, type A, consists of C-terminal ATTR fragments and full-length TTR, whereas the other, type B, consists only of full-length TTR. All organs of an individual patient contain ATTR deposits of either type A or type B fibrils, and the composition in each individual remains unchanged over time. The finding of two distinct types of ATTR fibrils suggests that there are at least two different pathways in operation for ATTR fibril formation. For the most common European mutation, TTR Val30Met, ATTR fibril composition is related to the outcome of liver transplantation, which is the first successful treatment for the disease, and the penetrance of the trait. In addition, the presence of C-terminal ATTR fragments has an impact on the affinity for various tracers used for noninvasive imaging of amyloid depositions such as 99 m-technetium-diphosphono-propanodicarboxylic acid scintigraphy and positron emission tomography utilizing Pittsburgh component B, and even for the gold standard diagnostic procedure, tissue biopsy stained by Congo red and examined under polarized light. The importance of amyloid fibril composition needs to be taken into consideration when designing clinical trials of treatment modalities, and also in the evaluation of diagnostic methods such as imaging techniques.

Supplement: 1, Special Issue: SI, Meeting Abstract: P300

Genetic defects of surfactant metabolism are associated with a broad range of clinical manifestations, from neonatal respiratory distress syndrome to adult interstitial lung disease. Early therapies may improve symptoms but diagnosis is often delayed owing to phenotype and genotype variability. Our objective was to characterize the cellular/ultrastructural correlates of surfactant protein C (SP-C) mutations in children with idiopathic diffuse lung diseases. We sequenced SFTPC-the gene encoding SP-C-SFTPB and ABCA3, and analyzed morphology, ultrastructure and SP expression in lung tissue when available. We identified eight subjects who were heterozygous for SP-C mutations. Median age at onset and clinical course were variable. None of the mutations were located in the mature peptide-encoding region, but were either in the pro-protein BRICHOS or linker C-terminal domains. Although lung morphology was similar to other genetic surfactant metabolism disorders, electron microscopy studies showed specific anomalies, suggesting surfactant homeostasis disruption, plus trafficking defects in the four subjects with linker domain mutation and protein misfolding in the single BRICHOS mutation carrier in whom material was available. Immunolabeling studies showed increased proSP-C staining in all cases. In two cases, amyloid deposits could be identified. Immunochemistry and ultrastructural studies may be useful for diagnostic purposes and for genotype interpretation.

Genetic defects of surfactant metabolism are associated with a broad range of clinical manifestations, from neonatal respiratory distress syndrome to adult interstitial lung disease. Early therapies may improve symptoms but diagnosis is often delayed owing to phenotype and genotype variability. Our objective was to characterize the cellular/ultrastructural correlates of surfactant protein C (SP-C) mutations in children with idiopathic diffuse lung diseases. We sequenced SFTPC-the gene encoding SP-C-SFTPB and ABCA3, and analyzed morphology, ultrastructure and SP expression in lung tissue when available. We identified eight subjects who were heterozygous for SP-C mutations. Median age at onset and clinical course were variable. None of the mutations were located in the mature peptide-encoding region, but were either in the pro-protein BRICHOS or linker C-terminal domains. Although lung morphology was similar to other genetic surfactant metabolism disorders, electron microscopy studies showed specific anomalies, suggesting surfactant homeostasis disruption, plus trafficking defects in the four subjects with linker domain mutation and protein misfolding in the single BRICHOS mutation carrier in whom material was available. Immunolabeling studies showed increased proSP-C staining in all cases. In two cases, amyloid deposits could be identified. Immunochemistry and ultrastructural studies may be useful for diagnostic purposes and for genotype interpretation.

The alkaline Congo red staining method has, for almost half a century, been the gold standard of amyloid diagnosis. Unfortunately, the method is both laborious and requires great skill to achieve proper diagnosis. In this study we are presenting an alternative method that is compatible with immunofluorescence typing. We used a novel dye, h-FTAA, designed and synthesized by us. The dye belongs to the novel class of conformation sensitive dyes known as Luminescent conjugated oligothiophenes (LCOs). We examined 37 different cases of systemic amyloidoses from various tissues. It was found that h-FTAA binds to amyloid with higher sensitivity and greater selectivity than Congo red, as was determined by both fluorescence- and light polarization microscopy. Due to the methods ease of use and performance compared to Congo red, it is concluded that h-FTAA is a better first choice for screening of systemic amyloidoses.

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Background: Mouse AA-amyloidosis is a transmissible disease by a prion-like mechanism where amyloid fibrils act by seeding. Synthetic peptides with no amyloid relationship can assemble into amyloid-like fibrils and these may have seeding capacity for amyloid proteins. Principal Findings: Several synthetic peptides, designed for nanotechnology, have been examined for their ability to produce fibrils with Congo red affinity and concomitant green birefringence, affinity for thioflavin S and to accelerate AA-amyloidosis in mice. It is shown that some amphiphilic fibril-forming peptides not only produced Congo red birefringence and showed affinity for thioflavin S, but they also shortened the lag phase for systemic AA-amyloidosis in mice when they were given intravenously at the time of inflammatory induction with silver nitride. Peptides, not forming amyloid-like fibrils, did not have such properties. Conclusions: These observations should caution researchers and those who work with synthetic peptides and their derivatives to be aware of the potential health concerns. © 2009 Westermark et al., Original Publication:P. Westermark, Katarzyna Lundmark and Gunilla Westermark, Fibrils from designed non-amyloid-related synthetic peptides induce AA-amyloidosis during inflammation in an animal model, 2009, PLoS ONE, (4), 6, e6041.http://dx.doi.org/10.1371/journal.pone.0006041

Background: Mouse AA-amyloidosis is a transmissible disease by a prion-like mechanism where amyloid fibrils act by seeding. Synthetic peptides with no amyloid relationship can assemble into amyloid-like fibrils and these may have seeding capacity for amyloid proteins. Principal Findings: Several synthetic peptides, designed for nanotechnology, have been examined for their ability to produce fibrils with Congo red affinity and concomitant green birefringence, affinity for thioflavin S and to accelerate AA-amyloidosis in mice. It is shown that some amphiphilic fibril-forming peptides not only produced Congo red birefringence and showed affinity for thioflavin S, but they also shortened the lag phase for systemic AA-amyloidosis in mice when they were given intravenously at the time of inflammatory induction with silver nitride. Peptides, not forming amyloid-like fibrils, did not have such properties. Conclusions: These observations should caution researchers and those who work with synthetic peptides and their derivatives to be aware of the potential health concerns. © 2009 Westermark et al., Original Publication:P. Westermark, Katarzyna Lundmark and Gunilla Westermark, Fibrils from designed non-amyloid-related synthetic peptides induce AA-amyloidosis during inflammation in an animal model, 2009, PLoS ONE, (4), 6, e6041.http://dx.doi.org/10.1371/journal.pone.0006041

Background: Mouse AA-amyloidosis is a transmissible disease by a prion-like mechanism where amyloid fibrils act by seeding. Synthetic peptides with no amyloid relationship can assemble into amyloid-like fibrils and these may have seeding capacity for amyloid proteins. Principal Findings: Several synthetic peptides, designed for nanotechnology, have been examined for their ability to produce fibrils with Congo red affinity and concomitant green birefringence, affinity for thioflavin S and to accelerate AA-amyloidosis in mice. It is shown that some amphiphilic fibril-forming peptides not only produced Congo red birefringence and showed affinity for thioflavin S, but they also shortened the lag phase for systemic AA-amyloidosis in mice when they were given intravenously at the time of inflammatory induction with silver nitride. Peptides, not forming amyloid-like fibrils, did not have such properties. Conclusions: These observations should caution researchers and those who work with synthetic peptides and their derivatives to be aware of the potential health concerns. © 2009 Westermark et al., Original Publication:P. Westermark, Katarzyna Lundmark and Gunilla Westermark, Fibrils from designed non-amyloid-related synthetic peptides induce AA-amyloidosis during inflammation in an animal model, 2009, PLoS ONE, (4), 6, e6041.http://dx.doi.org/10.1371/journal.pone.0006041

Background: Mouse AA-amyloidosis is a transmissible disease by a prion-like mechanism where amyloid fibrils act by seeding. Synthetic peptides with no amyloid relationship can assemble into amyloid-like fibrils and these may have seeding capacity for amyloid proteins. Principal Findings: Several synthetic peptides, designed for nanotechnology, have been examined for their ability to produce fibrils with Congo red affinity and concomitant green birefringence, affinity for thioflavin S and to accelerate AA-amyloidosis in mice. It is shown that some amphiphilic fibril-forming peptides not only produced Congo red birefringence and showed affinity for thioflavin S, but they also shortened the lag phase for systemic AA-amyloidosis in mice when they were given intravenously at the time of inflammatory induction with silver nitride. Peptides, not forming amyloid-like fibrils, did not have such properties. Conclusions: These observations should caution researchers and those who work with synthetic peptides and their derivatives to be aware of the potential health concerns. © 2009 Westermark et al., Original Publication:P. Westermark, Katarzyna Lundmark and Gunilla Westermark, Fibrils from designed non-amyloid-related synthetic peptides induce AA-amyloidosis during inflammation in an animal model, 2009, PLoS ONE, (4), 6, e6041.http://dx.doi.org/10.1371/journal.pone.0006041

Background: Mouse AA-amyloidosis is a transmissible disease by a prion-like mechanism where amyloid fibrils act by seeding. Synthetic peptides with no amyloid relationship can assemble into amyloid-like fibrils and these may have seeding capacity for amyloid proteins. Principal Findings: Several synthetic peptides, designed for nanotechnology, have been examined for their ability to produce fibrils with Congo red affinity and concomitant green birefringence, affinity for thioflavin S and to accelerate AA-amyloidosis in mice. It is shown that some amphiphilic fibril-forming peptides not only produced Congo red birefringence and showed affinity for thioflavin S, but they also shortened the lag phase for systemic AA-amyloidosis in mice when they were given intravenously at the time of inflammatory induction with silver nitride. Peptides, not forming amyloid-like fibrils, did not have such properties. Conclusions: These observations should caution researchers and those who work with synthetic peptides and their derivatives to be aware of the potential health concerns. © 2009 Westermark et al., Original Publication:P. Westermark, Katarzyna Lundmark and Gunilla Westermark, Fibrils from designed non-amyloid-related synthetic peptides induce AA-amyloidosis during inflammation in an animal model, 2009, PLoS ONE, (4), 6, e6041.http://dx.doi.org/10.1371/journal.pone.0006041

Background: Mouse AA-amyloidosis is a transmissible disease by a prion-like mechanism where amyloid fibrils act by seeding. Synthetic peptides with no amyloid relationship can assemble into amyloid-like fibrils and these may have seeding capacity for amyloid proteins. Principal Findings: Several synthetic peptides, designed for nanotechnology, have been examined for their ability to produce fibrils with Congo red affinity and concomitant green birefringence, affinity for thioflavin S and to accelerate AA-amyloidosis in mice. It is shown that some amphiphilic fibril-forming peptides not only produced Congo red birefringence and showed affinity for thioflavin S, but they also shortened the lag phase for systemic AA-amyloidosis in mice when they were given intravenously at the time of inflammatory induction with silver nitride. Peptides, not forming amyloid-like fibrils, did not have such properties. Conclusions: These observations should caution researchers and those who work with synthetic peptides and their derivatives to be aware of the potential health concerns. © 2009 Westermark et al., Original Publication:P. Westermark, Katarzyna Lundmark and Gunilla Westermark, Fibrils from designed non-amyloid-related synthetic peptides induce AA-amyloidosis during inflammation in an animal model, 2009, PLoS ONE, (4), 6, e6041.http://dx.doi.org/10.1371/journal.pone.0006041

Systemic AA-amyloidosis is a complication of chronic inflammatory diseases and the fibril protein AA derives from the acute phase reactant serum AA. AA-amyloidosis can be induced in mice by an inflammatory challenge. The lag phase before amyloid develops can be dramatically shortened by administration of a small amount of amyloid fibrils. Systemic AA-amyloidosis is transmissible in mice and may be so in humans. Since transmission can cross species barriers it is possible that AA-amyloidosis can be induced by amyloid in food, e.g. foie gras. In mice, development of AA-amyloidosis can also be accelerated by other components with amyloid-like properties. A new possible risk factor may appear with synthetically made fibrils from short peptides, constructed for tissue repair.

Swedish familial systemic amyloidosis with polyneuropathy (FAP) depends on a mutation leading to a methionine-for-valine substitution in transthyretin. The disease appears with different clinical manifestations, including age of onset and involvement of the heart. Liver transplantation is currently the only curative treatment, but progressive cardiomyopathy may occur post-transplant. Two amyloid deposition patterns have previously been described in the heart. In one, the amyloid consists partially of transthyretin fragments and is weakly stainable by Congo red, while in the other, only full-length molecules are found and the fibrils have a strong affinity for Congo red. The present study aimed to see whether these morphological and biochemical variations have clinical implications. Subcutaneous adipose tissue biopsies were taken from 33 patients with Val30Met FAP and examined by microscopy, electrophoresis and western blot. Clinical data included age, sex, duration of disease and echocardiographic determination of the interventricular septum (IVS) thickness. It was found that fibrils composed of only full-length transthyretin were associated with early age of onset (44.8 +/- 12.9 years), no clinical cardiac involvement and a strong affinity for Congo red. In contrast, presence of transthyretin fragments in the amyloid was associated with late age of onset (67.3 +/- 7.0 years), signs of cardiac involvement and weak Congo red staining. For each individual, the same molecular type of amyloid was found in different organs. This is the first report showing that variations in clinical appearance of familial ATTR amyloidosis are associated with specific structural differences in the amyloid fibrils, and therefore may have a molecular cause. The molecular type of amyloid can be determined from a subcutaneous fat tissue biopsy.

Swedish familial systemic amyloidosis with polyneuropathy (FAP) depends on a mutation leading to a methionine‐for‐valine substitution in transthyretin. The disease appears with different clinical manifestations, including age of onset and involvement of the heart. Liver transplantation is currently the only curative treatment, but progressive cardiomyopathy may occur post‐transplant. Two amyloid deposition patterns have previously been described in the heart. In one, the amyloid consists partially of transthyretin fragments and is weakly stainable by Congo red, while in the other, only full‐length molecules are found and the fibrils have a strong affinity for Congo red. The present study aimed to see whether these morphological and biochemical variations have clinical implications. Subcutaneous adipose tissue biopsies were taken from 33 patients with Val30Met FAP and examined by microscopy, electrophoresis and western blot. Clinical data included age, sex, duration of disease and echocardiographic determination of the interventricular septum (IVS) thickness. It was found that fibrils composed of only full‐length transthyretin were associated with early age of onset (44.8 ± 12.9 years), no clinical cardiac involvement and a strong affinity for Congo red. In contrast, presence of transthyretin fragments in the amyloid was associated with late age of onset (67.3 ± 7.0 years), signs of cardiac involvement and weak Congo red staining. For each individual, the same molecular type of amyloid was found in different organs. This is the first report showing that variations in clinical appearance of familial ATTR amyloidosis are associated with specific structural differences in the amyloid fibrils, and therefore may have a molecular cause. The molecular type of amyloid can be determined from a subcutaneous fat tissue biopsy.

[No abstract available]

The human cerebral and systemic amyloidoses and prion-associated spongiform encephalopathies are acquired or inherited protein folding disorders in which normally soluble proteins or peptides are converted into fibrillar aggregates. This is a nucleation-dependent process that can be initiated or accelerated by fibril seeds formed from homologous or heterologous amyloidogenic precursors that serve as an amyloid enhancing factor (AEF) and has pathogenic significance in that disease may be transmitted by oral ingestion or parenteral administration of these conformationally altered components. Except for infected brain tissue, specific dietary sources of AEF have not been identified. Here we report that commercially available duck- or goose-derived foie gras contains birefringent congophilic fibrillar material composed of serum amyloid A-related protein that acted as a potent AEF in a transgenic murine model of secondary (amyloid A protein) amyloidosis. When such mice were injected with or fed amyloid extracted from foie gras, the animals developed extensive systemic pathological deposits. These experimental data provide evidence that an amyloid-containing food product hastened the development of amyloid protein A amyloidosis in a susceptible population. On this basis, we posit that this and perhaps other forms of amyloidosis may be transmissible, akin to the infectious nature of prion-related illnesses. © 2007 by The National Academy of Sciences of the USA.

Aims/hypothesis: Islet amyloid is a frequent finding in the islets of Langerhans of individuals with type 2 diabetes. The main amyloid constituent is the beta cell-derived polypeptide hormone islet amyloid polypeptide (IAPP). In general, amyloid refers to an extracellular deposit of a congophilic material, but intracellular amyloid is seen in some beta cells of transgenic mice expressing the gene for human IAPP and in human islets transplanted into nude mice. The aim of this study was to immunohistochemically characterise the intracellular amyloid. Methods: Antisera against the N- and C-terminal processing sites of proIAPP (which were therefore specific for proIAPP), the C-terminal flanking peptide and mature IAPP were used for immunoelectron microscopy. Results: Fibrillar aggregates were seen in the halo region of the secretory granules in some beta cells in human IAPP transgenic mice. These aggregates were labelled with proIAPP-specific antisera. Also, proIAPP reactivity was more widespread in the intracellular amyloid-like aggregates in beta cells of transgenic mice than in human islet transplants, in which the intracellular amyloid-like deposits were larger, but the proIAPP labelling was restricted to small spots within the amyloid deposits. Conclusions/ interpretation: We suggest that proIAPP forms the first amyloid fibrils and that this can occur already in the secretory granules of the beta cells. The proIAPP-derived fibrils can act as seed for further amyloid formation, now made up by IAPP. The observed difference between human islet transplants and human IAPP transgenic animals may reflect differences in stages of amyloid development. © Springer-Verlag 2006.

OBJECTIVE - To evaluate whether treatment with insulin in recently diagnosed type 2 diabetes is advantageous compared with glibenclamide treatment. RESEARCH DESIGN AND METHODS - ▀-Cell function, glycemic control, and quality of life were monitored over 2 years in 39 patients with islet cell antibody-negative type 2 diabetes diagnosed 0-2 years before inclusion in a Swedish multicenter randomized clinical trial. Patients were randomized to either two daily injections of premixed 30% soluble and 70% NPH insulin or glibenclamide (3.5-10.5 mg daily). C-peptide-glucagon tests were performed yearly in duplicate after 2-3 days of temporary withdrawal of treatment. RESULTS - After 1 year the glucagon-stimulated C-peptide response was increased in the insulin-treated group by 0.14 ▒ 0.08 nmol/l, whereas it was decreased by 0.12 ▒ 0.08 nmol/l in the glibenclamide group, P < 0.02 for difference between groups. After 2 years, fasting insulin levels were higher after treatment withdrawal in the insulin-treated versus the glibenclamide-treated group (P = 0.02). HbA1c levels decreased significantly during the first year in both groups, however, at the end of the second year, HbA1c had deteriorated in the glibenclamide group (P < 0.01), but not in the insulin-treated group. The difference in evolution of HbA1c during the second year was significant between groups, P < 0.02 A questionnaire indicated no difference in well-being related to treatment. CONCLUSIONS - Early insulin versus glibenclamide treatment in type 2 diabetes temporarily prolongs endogenous insulin secretion and promotes better metabolic control.

In previous studies we have shown that apparently normal human islets, transplanted under the renal capsule of nude mice, frequently and rapidly develop amyloid deposits derived from the ▀-cell hormone islet amyloid polypeptide (IAPP). In the present study, we show for the first time that human islets, transplanted into the liver or spleen of nude mice, also develop islet amyloid rapidly. Ultrastructural studies of such islets showed that the first aggregation of IAPP takes place within the ▀-cells and that extracellular deposits show up later in the amyloid formation process. We also found that the amount of amyloid formed in human islet grafts placed under the kidney capsule increased with extended (26 weeks) observation time. Moreover, prolonged in vitro culture (14 days) prior to the implantation under the renal capsule seemed to enhance the formation of amyloid in the grafted islets. Since aggregated IAPP has been shown to be toxic to ▀-cells, the finding of amyloid deposits in transplanted islets offers a possible explanation to the frequent loss of function of islets transplanted into diabetic patients.

Calcifying epithelial odontogenic tumors (CEOTs), also known as Pindborg tumors, are characterized by the presence of squamous-cell proliferation, calcification, and, notably, amyloid deposits. On the basis of immunohistochemical analyses, the amyloidogenic component had heretofore been deemed to consist of cytokeratin-related or other molecules, however, its chemical composition had never been elucidated. We have used our microanalytic techniques to characterize the protein nature of CEOT-associated amyloid isolated from specimens obtained from 3 patients. As evidenced by the results of amino-acid sequencing and mass spectrometry, the fibrils were found to be composed of a polypeptide of approximately 46 mer. This component was identical in sequence to the N-terminal portion of a hypothetical 153-residue protein encoded by the FLJ20513 gene cloned from the human KATO III cell line. That the amyloid protein was derived from this larger molecule was demonstrated by reverse transcription-polymerase chain reaction amplification of tumor-cell RNA where a full-length FLJ20513 transcript was found. Furthermore, immunohistochemical analyses revealed that the amyloid within the CEOTs immunostained with antibodies prepared against a synthetic FLJ20513-related dodecapeptide. Out studies provide unequivocal evidence that CEOT-associated amyloid consists of a unique and previously undescribed protein that we provisionally designate APin.

Fine-needle aspiration (FNA) cytology is a rapid and inexpensive technique used extensively in the diagnosis of breast disease. To remove diagnostic subjectivity, a diagnostic decision support system (DDSS) called CytoInform© has been developed, based on a Bayesian belief network (BBN) for the diagnosis of breast FNAs. In addition to acting as a DDSS, the system implements a computer-based training (CBT) system, providing a novel approach to breast cytology training. The system guides the trainee cytopathologist through the diagnostic process, allowing the user to grade each diagnostic feature using a set of on-screen reference images as visual clues. The trainee positions a slider on a spectrum relative to these images, reflecting the similarity between the reference image and the microscope image. From this, an evidence vector is generated, allowing the current diagnostic probability to be updated by the BBN. As the trainee assesses each clue, the evidence entered is compared with that of the expert through the use of a defined teaching file. This file records the relative severity of each clue and a tolerance band within which the trainee must position the slider. When all clues in the teaching case have been completed, the system informs the user of inaccuracies and offers the ability to reassess problematic features. In trials with two pathologists of different experience and a series of ten cases, the system provided an effective tool in conveying diagnostic evidence and protocols to trainees. This is evident from the fact that each pathologist only misinterpreted one case and a total of 86%/88% (experienced/inexperienced) of all clues assessed were interpreted correctly. Significantly, in all cases that produced the correct final diagnostic probability, the route taken to that solution was consistent with the expert's solution. Copyright © 2001 John Wiley & Sons, Ltd.

Islet amyloid polypeptide (IAPP, "amylin") is the amyloid-fibril-forming polypeptide in the islets of Langerhans associated with type 2 diabetes mellitus. A missense mutation in the IAPP gene associated with early-onset type 2 diabetes has been identified in the Japanese population. This mutation results in a glycine for serine substitution at position 20 of the mature IAPP molecule. Whether or not formation of islet amyloid with resulting destruction of islet tissue is the cause of this diabetes is yet not known. The present in vitro study was performed in order to investigate any influence of the amino acid substitution on the fibril formation capacity. Synthetic full-length wild type (IAPPwt) and mutant (IAPPS20G) as well as corresponding truncated peptides (position 18-29) were dissolved in dimethylsulfoxide (DMSO) or in 10% acetic acid at a concentration of 10 mg/mL and their fibril forming capacity was checked by Congo red staining, electron microscopy, a Congo red affinity assay and Thioflavine Tfluorometric assay. It was found that full-length and truncated IAPPS20G both formed more amyloid-like fibrils and did this faster compared to IAPPwt. The fibril morphology differed slightly between the preparations. Conclusion: The amino acid substitution (S20G) is situated close to the region of the IAPP molecule implicated in the IAPP fibrillogenesis. The significantly increased formation of amyloid-like fibrils by IAPPS20G is highly interesting and may be associated with an increased islet amyloid formation in vivo and of fundamental importance in the pathogenesis of this specific form of diabetes.